Thursday, May 16, 2013

Suzio Report April 6

Howdy Herpers,                                                        

About 20 miles north of the center of Tucson lies a mountain range called the Tortolita Mountains. While the Tortolitas are rather vast in the area that they cover, they don’t exactly tower majestically above the flat landscape that surrounds them. At a distance, they are rather drab in appearance, mundane, not eye-catchers by any stretch of the imagination. I would venture that over half the people in Tucson, (the environmentally brain dead half), have never even noticed them, let alone know them by name.

Back in the early 1980s, this range was remote, and well outside the perimeter of civilization. When we wanted to get into the true wilds of Arizona, we’d drive down a two-track as far as we could along the southern edge, and then bushwhack in. We’d find lots of relics from the ancient ones. Arrow heads, pottery shards, petroglyphs. The Southern Tortolitas were a little known treasure, with steep, boulder infested hillsides that were in turn studded with dense Saguaro forests.

There is a road called Tangerine Road that flanks the southern edge of the range. This was a paved road even in the 80s, but traffic was near nil. It was a great road to cruise for herps. Back in 1983, I got my first glimpse of a wild Gila Monster on that road. Right where it makes the big bend, about a half kilometer from I-10. It was a DOR, but very fresh, with vibrant colors, and in pristine shape. I pried open its snappers, and marveled at the sharp, hooked teeth, and forked tongue. I was understandably excited with the find, and even picked it up off the road and put it in my vehicle. Off I drove with it lying on the floorboard on the passenger side of my Nissan. I was going to take it home to show my family and friends. But then, the laws being what they are, I freaked out, and took it back to where I found it. I lovingly placed it several paces off the road. I couldn’t bear to put it back on the road as found. It somehow seemed more dignified to have its final resting place under a creosote, than to leave it on the road as miniature speed bump.

In May of 1985, I was barreling down 1-10 with a buddy of mine. We were heading to the Chiricahua Mountains for a hike in the monument. About the time that we hit the Spanish Trail exit, I saw a Gila Monster traveling south across the freeway. It was just starting to cross the road. My poor hiking buddy will never understand what happened next, for John was not a herper. (In other words, he was “normal.” They’re all around us.)

I locked up the brakes, veered right, and managed to come to scorching stop about 100 meters past the point where the monster had been first spotted. Without a word, I swung open the door, (not bothering to close it), and wind-sprinted back through the smoldering black smoke that is synonymous with 20,000 miles of brake lining and tire rubber being erased from the respective life-expectancy of each.

These were the days when I could wind-sprint. I was lean, I was fast, I was strong­and MAN was I ever jacked up to catch that Gila Monster! I’ll never forget the jostling view of that monster entering the left lane as the ground evaporated beneath the rapidly rhythmic thudding of feet. By the time I pulled within 20 meters of the monster, despite the speed of my approach, and despite the determination and adrenaline flow, I began to see that this was going to end badly. Now the monster was on the centerline, with an 18 wheeler bearing down on it like there was no tomorrow. I cut in front of the semi, head on, and tried to wave him over into the left lane while I closed the final distance between the monster and I. The plan in my mind was clear. The trucker would see me gunning for the Gila Monster, and then being the “knight of the road” that truckers are reputed to be, he would yield to the oncoming geek charge. But Mr. Trucker had other ideas. His remedy for the situation was to lay on his air horn, whilst staying his course. When I was a scant five meters from the monster, and perhaps 20 meters from the oncoming semi, I saw the hopelessness of it all. As I sprinted in front of the barreling semi to get to the left lane and out of his way, I tossed a “deer-in-the headlights” look his way. The burly, bearded sunovabitch was not attempting to slow down. If anything, he was speeding up! The last look I had of him was at very close range. And I swear to God he was laughing! And then came the dwindling Doppler effect of the air horn roaring past, lessening in intensity as distance overcame sound, and the swirling road dust sand-blasting my being. Far worse than that was the sight of my second-ever wild Gila Monster plastered to the pavement like a bloody road Frisbee. Ten years of my life were lost in the bellicose cussing that followed. What an asshole!  

I moved to Tucson in 1981. In selecting a place to settle down, finding a wild Gila Monster weighed in as a heavy factor in the relocation process. In 1983, the dead one on Tangerine Road came my way. Then, in 1985, it was literally “east bound and down” with the second. It was not until April of 1989 that I saw my next wild Gila Monster. And FINALLY that one was alive. I went 7 years and 11 months to consummate my dream of seeing a living Gila Monster in the wild.

Tangerine Road is no longer a quaint little paved road suitable for road cruising. It is now mostly a 15 mile stretch of four lane super highway. There are still a few patches of wild Sonoran Desert flanking it, but that ain’t much. And that is surely going to fall soon. Many developments such as Dove Mountain, Stone Canyon, and too many others to enumerate here have engulfed the best of what the southern Tortolitas used to be. Tiger Woods swings his driver where we used to herp.

But the north side of the range is still good. And it was here, in a vast canyon that some of us know as April Canyon, that I saw my first wild Gila Monster. The story of this find is a long one, so I will save it. Said story has already been documented. It can be found on the Tucson Herpetological Society website. Go for “Publications,” “Collected Papers,” and find page 163.

The experience of seeing that first wild Gila Monster was one of reverence for this herper. It is only natural that I would hold the ground on which it was found with the same regard. Once a year, I go back to April Canyon. Twenty-four years later, it still remains largely unchanged from the day I saw my first Gila.

This year, it was on 6 April 2013 that I revisited my Heloderma Alma Mata. Marty Feldner, Karla Moeller, Megan Morgan and I met at 0805 that morning. We were supposed to meet at 0800, but Marty was late by 5 minutes. As there was no sense whatsoever in being prompt if Marty was going to be late, I arrived just after he did. There was more than the usual flandickery in preparing to drive to our final destination. Marty had scooped a young male DOR Mojave Rattlesnake off the road enroute in, and no small amount of time was spent fondling and admiring that. Then, in order to make room for everybody, I had to unload 20 tons of camping gear into Karla’s war wagon. But all that was eventually behind us. Chivalry died back in the 90s, when women started to demand equal rights. Hence, we put the women in the back of the bus, Marty promptly settled into the shotgun seat, and I took the wheel of my White Knight. Bap! We were heading eastward to April Canyon.

There was a brief moment of excitement when Marty spotted an average-sized male diamondback rattlesnake on the right side of the quad trail that we were negotiating. The White Night regurgitated its vehicular contents, and we all encircled the snake to commune with him for a few minutes. We left him none the worse for the wear, and he was no doubt happy to see us go.

We arrived at April Canyon at precisely 0900. The air temp was 22C, it was cloudless. My trusty Kestrel indicated there was 20% humidity, and a 0-3 mile-per-hour breeze. We were at 3400 feet in elevation. I’m the only one of the group who knows these things, as I was the only one to take the time to document it all. The other three left me behind like a soiled hanky while I did so.

I showed Karla this place because she needs to fully process ten different adult Gila Monsters in April, and ten again in June. April Canyon is a place where that is possible. To reveal any more of the purpose for being there is not ethical. Karla’s work needs to be done in a quiet manner. It is hoped that we will learn something about the physiological effects of drought on Gila Monsters. If in the process, we free Tibet, we won’t complain. And my purpose for being there was to see herps. Any Gila Monsters would be a bonus.

By the time I had finished all the documentation, my three companions were out of sight. At this point, April Canyon is a wide open sandy wash that narrows as one ascends up canyon. Both sides of the canyon are flanked with lush desert vegetation. The mesquites grow tall and mighty here, and dense thickets of hackberry and nasty catclaw abound. I was able to see where the group did not walk, and started my route up in that direction. I immediately found an adult female diamondback stretched out in the sand, heading across the wash in westerly fashion. I tried snapping some undisturbed images, but she drew into a semi-defensive posture, and began pedaling away from me, with head held high and rattles singing. About the time this one was found, Marty found another. His was a male.

At 0925, I caught up with the group. They were all huddled together in wash center. They had found their first Gila Monster. It was an adult female that Marty had found in the center of the wash. She was found with snout in the sand, and had been digging. She was processed and released to get on with her life. Shortly after this experience, Megan was pointing to something chest high in the trees and murmuring in her soft voice. This eventually brought us all to her side.

Thrust upon a horizontal branch of a mesquite tree was the head and neck of a diamondback rattlesnake. A CRAT-sickle! It was fairly fresh, as the eyes were still in the sockets, and the black tongue still dangled out of its gaping mouth. It served as grotesque  reminder that all who enter April Canyon are not nature lovers. It is this kind of crap that causes us to hate so many people who abuse the sanctity of our wild places. We grow ever-tired of the ignorance of those who invade nature under the guise of appreciating her, only to be offended when she comes calling. (Or, in this case, “comes crawling”). It is impossible to fathom the blatant and consistent lack of respect for living organisms that is shown for some of our wildlife. What assholes!

The next round of excitement occurred when Marty spotted a mid-sized gophersnake sprawled lengthwise at the west edge of the wash. At first, the snake remained motionless, and we tried to move in for some pictures. Then, it began slithering slowly eastward across the wash in front of us. Megan had fallen behind us in the search effort, so we called her up for a look. Karla was on the slope above us, to the east of the action. She asked of us if it was worth her coming down to view the snake, and we replied that it was nothing spectacular. It was just shy of a meter long, just a scrawny “nuthin’ special” sort of gophersnake. (How dare I say that a gophersnake is “nothin’ special!” They’re all special, but not when the focus is on other things. Were it a five-foot long hefty beauty, Karla would have been severely berated if she even hesitated to come down for a look). Moments later, the nuthin’ special snake slid into some overhanging roots of a mesquite on the east berm of the wash. It was at this point that nuthin’ special morphed into “sumthin’ special,” for within the framework of those mesquite roots was a Gila Monster!

“NOW you need to come down, Karla!”

We waited patiently before moving in to process this second monster, in hopes that maybe the gophersnake would attempt to interact with it. But by this time, both animals were aware of our presence, spooked to the max, and there was to be no excitement save for that of having two cool species of herp occupy the same patch of ground. The gophersnake was left to get on with its life. The Gila Monster did not get off quite that easily, but the processing went smoothly. This one was a dandy of a male. His mass was 591 grams, and he was 553mm (21.77 inches) in total length. Certainly not a record length or mass by any means, but he was a healthy monster by Sonoran Desert standards.

Earlier in this narrative, the first glimmers of Gila Monsters in my life were mentioned. By the time that first April Canyon Gila Monster was discovered, I had a friendly association with one of the early monster masters in our region. We speak of Brent Martin. By the late 1980s, Brent claimed that he had found over 200 of them. He was also quick to point out that this impressive total was accumulated through decades of seeking them. While I believed Brent, that number of 200 seemed astronomical. It was a record that I could never even approach. A careful search of my records indicates that our nuthin’ special gophersnake led us to wild Gila Monster number 305. The simple number of 305 just doesn’t look right when spelled out numerically. That ain’t saying it proper. Let’s put that number in writing. THREE HUNDRED FIVE Gila Monsters! Yeah, baby! And there wasn’t even a ticker-tape parade to honor the event……..

We left number 3-oh-5 to get on with his life. And the search for number 306 was on. It was ascertained that it was time to head back down the canyon. A short while later, Marty sounded off, “Monster!” This one was found sprawled in a dense thicket of catclaw, on the east berm of the wash. It was a vividly-colored juvenile, which unfortunately was of no use to Karla. However, as a DNA sample, it was useful to those who Marty and I serve. Mother Repp never raised a child so foolish as to plunge into a catclaw thicket after a monster that he didn’t even find. Marty found the darn thing, let him be the hero! Yeah! Let Marty do it! Go get her, boy! By the time Marty had her, the harsh shrubbery was gaily festooned with strips of Marty bacon. Let that be a lesson to the lad about finding things among pernicious plant parts……….

This monster turned out to be a female, we would estimate entering the fourth year of her sweet young life. We all took turns taking pictures, and Karla drew a little blood for the DeNardo lab. Once we were done having our way with her, we simply let her go to see what she would do. What she did proved to be the highlight of the day. At the point where we turned her loose, she was roughly 20 meters up wash from her capture spot. Rather than heading in that direction, she bolted for the cover on the east berm. She approached a burly, vertical scaly trunk of a massive mesquite, and began deftly crawling up it. She stopped her ascent when she was about two meters above the ground. She was a sitting duck for the photographs that followed.

This is only the second time that I have witnessed a monster go arboreal. This puny N of 2 not only takes into consideration the 306 different wild Gila Monsters observed over the past 25 years, but also includes well over a thousand observations on telemetered animals as well. The first time we witnessed this happening was with our telemetered Gila Monster #15. He earned the name “Tarzan” as a result of his climb. In both cases, there is evidence that escape from human interlopers was the possible motive. And just recently, Marty has sent along an image of a third monster that he saw start up a mesquite, again possibly to avoid capture. Unlike their cousins the Beaded Lizards, which are avid tree climbers, it appears that this behavior is only rarely encountered with Gila Monsters.

Getting back to 6 April, whilst going off on a paragraph of bygone days, we left our juvy Gila clinging tenaciously two meters above ground on the trunk of a mesquite tree. There was some discussion amongst the fab four about leaving her there like so much painted fruit. But our desire to feed the local raptors was minimal, and she was snatched from her moorings and released into the briar patch from whence she came. It is hoped that she was able to snack on some of the Marty bacon that was so generously hung for her.

It was 12:30 when we got back to the White Knight. I was a half hour late for my first beer of the day. Those who bottle Dos Equis were on high alert, and the workers were fearful of lengthy furloughs. The world’s most interesting man grew boring, developed a stutter, and began picking his nose in public. On a more personal note, by the time I got the cap off the bottle, little pink elephants were swirling about, and closing in on me in a most menacing manner. Disaster was narrowly avoided here.

Speaking of disasters, lunch came next. Marty and I are not accustomed to the field fare that the folk in DeNardo’s lab subsist upon. Instead of steak and lobster, these kids serve blobs of brown and red sticky substances slathered on wonder bread. And they think they are walking in tall cotton by doing so. The temptation to hike back for some strips of Marty bacon was strong, and we began eyeing the maggots in the abundant drying cowpies as potential side dishes. This is what you get when you let KIDS lead the charge! When left to our own devices, every meal is a banquet. The next time we are in Rome, we will not do as the Romans do!        

By 2 PM, we were just sitting around looking at each other. Marty began to talk about eating people. Cannibalism is a favored topic of his, especially when he is feeling malnourished. I expect Marty to talk about eating people when he is hungry, so there was no problem thus far. When the ladies wholeheartedly joined in Marty’s conversation, things got a little scary. Talk of cannibalism often results when the troops in the field are underfed and bored. The idle mind is the devil’s workshop, and it was time to think of something to do. (Lest one of us wind up in the cooking pot). My suggestion that we take a road cruise to 96 Hills in order to just keep moving was met with universal acceptance. Marty and I are old hands at counting lizards, and there were plenty to count on this hot spring afternoon. Soon, the boredom overtook the ladies, and they joined right in there to help.

“There are 2, no 3, no 4, 5-6-7, 9! 12! 14!” We were all singing out from all sides of the White Knight. Every 50 feet or so, we would jump the Zebra-tailed Lizards. When all was said and done with our otherwise pointless road cruise, we had racked up 237 of them! We also scored 10 Side-blotched Lizards, 4 Clark’s Spiny Lizards, 5 Desert Spiny Lizards, 18 Greater Earless Lizards, 6 Whiptails, 3 Tree Lizards, and 2 Leopard Lizards. The capper of the drive occurred at 1610 in the afternoon. I saw a smallish lizard waddle off to the side of the road into some tall grass. I stopped the vehicle, and was all sorts of insistent that we had just seen a Regal Horned Lizard. Others protested this not to be true.  I resisted the urge to get aggressive in my assertions, as I really wasn’t that sure. But we kept looking anyhow, and sure enough, Karla fished the horny toad out of the shrubbery. The crowd went wild! By the time that dusk rolled around, and the lizard activity stopped, we had racked up 289 lizards, with ten different species represented. That ought to help with my lizard count for the year of 2013. The numbers of Zebra-tailed lizards have been rather lackluster of late. It was one hell of a lizard day!

Just after the horned lizard, there was some universal lamenting about the lack of snakes on this road cruise. Just as soon as the grousing started, as if on queue, a meter long all black Coachwhip was observed in the center of the dusty road. It was one very jacked up snake. The ground-hugging greased lightning zipped to the side of the road, and evaporated, leaving a little black vapor trail in its wake. Despite further effort, that was to be the last good find of the day.

In closing this epic journey about a good herping day, perhaps a reminder to those of us who are blessed to live in Arizona is in order. We live in a place that epitomizes freedom. We can roam at will through a variety of habitats that range from sand dunes to above timberline. We should never take our public lands for granted, for it is these places that allow escape from the rat race of daily living. We can travel dirt roads, find a hill to climb, stand alone, and take back something worth remembering. And best of all, we live in a place where at any given moment, a gaudy orange and black hefty lizard can lumber across our path, and make our day.

This here is Roger Repp, signing off from Southern Arizona, where the turtles are strong, the snakes are handsome, and the lizards are all above average.

Images: The images that fall below were carefully arranged to follow the flow of this fabulous day. See text above for explanations. Images by Roger Repp and Marty Feldner.

Monday, May 13, 2013

Cannibalistic Tadpoles

The face of an unfortunate Budgett's frog tadpole
that is being digested inside the stomach of its larger

A carnivorous, cannibalistic tadpole may play a role in understanding the evolution and development of digestive organs, according to research from North Carolina State University. These findings may also shed light on universal rules of organ development that could lead to better diagnosis and prevention of intestinal birth defects.

NC State developmental biologist Nanette Nascone-Yoder, graduate student Stephanie Bloom and postdoc Cris Ledon-Rettig looked at Xenopus laevis (African clawed frog) and Lepidobatrachus laevis (Budgett’s frog) tadpoles. These frog species differ in diet and last shared a common ancestor about 110 million years ago. Like most tadpoles, Xenopus exist primarily on a diet of algae, and their long, simple digestive tracts are not able to process insects or proteins until they become adult frogs. Budgett’s is an aggressive species of frog which is carnivorous – and cannibalistic – in the tadpole stage.

Nascone-Yoder knew that Budgett’s tadpoles had evolved shorter, more complex guts to digest protein much earlier in their development. She and her team exposed Xenopus embryos to molecules that inactivated a variety of genes to see if any might coax Xenopus to develop a more carnivore-like digestive tract. Remarkably, five molecules caused Xenopus tadpoles to develop guts that were closer in appearance to those of the Budgett’s tadpoles. Taking it one step further, Nascone-Yoder exposed Budgett’s frog embryos to molecules with opposite effects, and got tadpole guts that were closer to those of Xenopus.

“Essentially, these molecules are allowing us to tease apart the processes that play a key role in gut development,” Nascone-Yoder says. “Understanding how and why the gut develops different shapes and lengths to adapt to different diets and environments during evolution gives us insight into what types of processes can be altered in the context of human birth defects, another scenario in which the gut also changes its shape and function.”

The researchers’ next steps include finding out whether the changes in these gut tubes were merely cosmetic, or if they also function (digest) differently.

Bloom S,  Ledon-Rettig C, Infante C,  Everly A,   Hanken J, Nascone-Yoder N. (2013) Developmental origins of a novel gut morphology in frogs. Evolution & Development,  15 (3): 213 DOI: 10.1111/ede.12035

Friday, May 10, 2013

The Value of Unexpected Creatures

Recently I did a snake workshop for people who knew little about snakes, but were otherwise very well educated in various fields of endeavor (law, medicine, psychology). While discussing gliding snakes, one participant commented to the effect that we now have to worry about flying snakes. The comment was a reminder that the general public, even the well educated general public, lacks an appreciation for biodiversity.

[To the right: Wallace painted this watercolor of Rhacophorus 
nigropalmatus in 1855. At the time this was an undescribed species. Wallace wrote on the back of the watercolor the frog “descended from a high tree as if flying.” © ALFRED RUSSEL

Appreciation for biodiversity is a core attitude for halting or at least slowing the current extinction event that we are experiencing. A society that understands ecology, evolution and biodiversity - natural history - is less inclined to be deluded by the idea that humans are in charge of the planet, and can act independently from nature and the ecosystem.

Unexpected creature can form the basis for the teachable moment. The moment that a person realizes there is more to the world that the societal myths that keep the masses occupied.  Yandell (2013) commented on the recent discovery of Alfred Russel Wallace's watercolor of the giant flying frog (Rhacophorus nigropalmatus). Wallace did the painting in 1855 shortly after a local Malaysian collected the frog and presented it to Wallace. The watercolor was used to produce the woodcut print in his 1869 book The Malay Archipelago.

Flying frogs and snakes are out of the ordinary, gliding and parachuting behavior is not something expected of amphibians and reptiles. Venomous squamates are also high interest herps that can attract the attention of the modern technological zombie. But there are many other unexpected species that can spark interest in the natural world. The giant Chinese salamander, Andrias davidianus, a completely aquatic, giant amphibian that reaches 1.8 meters in length. The tentacled snake, Erpeton tentaculatus, with a pair of rostral appendages making it the most distinctive serpent on the planet And, the mata mata turtle, Chelus fimbriatus, a bizarre highly aquatic turtle that creates a  vacuum to capture prey.

Whatever your favorite unexpected creature happens to be consider using it to introduce someone else to the world they live in.

Yandell, K. 2013. Flying Frog, 1855. The Scientist.

Thursday, May 9, 2013

Rana iberica's hidden life underground

Do frogs live underground? The answer is yes, some amphibians, such as salamanders and frogs have been often reported to dwell in subterranean habitats, some of them completely adjusted to the life in darkness, and others just spending a phase of their life cycle in an underground shelter. Up until 2010, however, no one suspected that the Mediterranean frog Rana iberica - commonly known as Iberian brown frog and usually found in streams - also participates in underground adventures. A new study published in the open access journal Subterranean Biology confirms the first report of Rana iberica reproduction in a cave-like habitat, with all life stages observed in the galleries.

Serra da Estrela Natural Park is located in north-central Portugal and is the largest protected area and one of the most biodiverse regions in Portugal and the Iberian Peninsula. Several drainage galleries were created for water capture in the 1950s, even before the establishment of the boundaries of the Natural Park. It is namely in these artificial subterranean habitats that the Iberian brown frog was discovered dwelling underground by biologists.

"The unusual sighting of R. iberica motivated a series of subsequent visits that started in 2011 up until December 2012 to understand the use of this artificial subterranean habitat by this species.", explains the lead author of the study Dr. Gonçalo M. Rosa. "All life stages were observed in the gallery during the study period, particularly adults, which were observed every month of the year."

The Iberian brown frog does not only seek refuge in the drainage galleries as a sporadic visitor. During long observations, adults from the species have been noted in the galleries,often standing on the ground or in crevices, swimming underwater or even climbing up the walls. There is evidence of mating activity, and batches of eggs have been found stuck to submerged rocks in the subterranean stream. Recently hatched tadpoles were also observed, initially remaining stationary above the egg mass for about two weeks, then swimming in the streams and feeding on the dead egg mass. The galleries are used by other amphibians as well, and larvae of the fire salamander Salamandra salamandra gallaica have been recorded twice while preying on brown frog tadpoles.

The choice of the artificial drainage gallery for a habitat of the Iberian brown frog may appear odd initially. However, it seems that the animals find a refuge in the cool and humid tunnels, often containing a small stream. These artificial subterranean habitats are in fact often used as a refuge for many species. They are, for example, particularly important for the salamander Chioglossa lusitanica, an Iberian endemic of conservation concern. Scientists express their fear that such preferences for underground habitats might in fact be a sign for the ecological dangers of the dramatic climate changes experienced by the Iberian region. Monitoring the subterranean activity of various species might provide important cues for future conservation efforts. The entire article is available on-line.

Rosa GM, Penado A (2013) Rana iberica (Boulenger, 1879) goes underground: subterranean habitat usage and new insights on natural history. Subterranean Biology 11: 15–29, doi: 10.3897/subtbiol.11.5170

Wednesday, May 8, 2013

Midwest frogs & mammal populations altered by invasive plant

Western Chorus Frogs in amplexus. JCM
The following is a press release from Lincoln Park Zoo.

Researchers at Lincoln Park Zoo and Northern Illinois University have discovered a new culprit contributing to amphibian decline and altered mammal distribution throughout the Midwest region – the invasive plant European buckthorn. This non-native shrub,  which has invaded two-thirds of the United States, has long been known to negatively impact plant community composition and forest structure, but these two innovative studies slated to publish in upcoming editions of the Journal of Herpetology and Natural Areas Journal demonstrate how this shrub negatively impacts native amphibians and affects habitat use by mammals including increased prevalence of coyotes and other carnivores.

Amphibians are facing an extinction crisis worldwide, with 165 species likely having gone extinct in recent years according to the Amphibian Ark, a coalition of conservationists devoted to seeking solutions to the decline. Lincoln Park Zoo Reintroduction Biologist Allison SacerdoteVelat, Ph.D. and Northern Illinois University Professor of Biological Sciences Richard King have identified European buckthorn as a contributor to amphibian decline in the Chicagoland area. The plant releases the chemical compound emodin, which is produced in the leaves, fruit, bark and roots of the plant, into the amphibian breeding pond environment at various times of year. Sacerdote-Velat and King’s research has found that emodin is toxic to amphibian embryos, disrupting their development, preventing hatching.

"Levels of emodin in the environment are greatest at leaf out, which is occurring right now in early spring. This coincides with breeding activity of several early-breeding Midwestern amphibian species including western chorus frogs and blue-spotted salamanders," explained Sacerdote-Velat. "Several amphibian species exhibit low hatching rates in sites that are heavily infested with European buckthorn."The Chicago Wilderness 2004 Woodland Audit found that in the Chicagoland area alone, more  than 26 million stems of European buckthorn exist with a density of 558 stems per acre. Whilst this study specifically found emodin to detrimentally impact development of two species of frogs, Western chorus frogs and African clawed frog (a common test species for environmental toxicity studies), Sacerdote-Velat and King hypothesize that emodin may impact the reproductive success of other frog species in regions where buckthorn is not native.

“Western chorus frogs are quite common in the Midwest, and people in Illinois who have never seen them have probably heard them in the springtime,” said King, who has continued to conduct research with Sacerdote-Velat after having served as her Ph.D. adviser at NIU. “The new study demonstrates how a shrub that is viewed by many as a decorative plant can become invasive and have unexpected and damaging effects on natural ecosystems.”

Additionally, new research from the zoo’s Urban Wildlife Institute reveals how the presence of the invasive shrub in forest preserves and natural areas correlates to increased prevalence of carnivores. Previous research by Ken Schmidt of Texas Tech University and Chris Whelan of Illinois Natural History Survey documented that these carnivores can prey more easily on native bird eggs and nestlings such as robins when nests are built in buckthorn and honeysuckle compared to nests built in native shrubs or trees.

“The relationship between invasive plants and wildlife is complex. This is the first study of its kind to investigate the association between buckthorn and habitat use by mammal species,” explained Director of the Urban Wildlife Institute Seth Magle, Ph.D. “We know based on prior research that birds which build nests in buckthorn are more susceptible to predation. Our study found that the presence of buckthorn alters wildlife distribution and attracts some carnivore species. We now know that there are significantly more coyotes, raccoons and opossums in buckthorn invaded areas, and significantly fewer white-tailed deer.”

Magle hypothesizes that the carnivores could be drawn to buckthorn areas because birds and their nests are easier to prey upon. He suggests that deer may be avoiding these areas because buckthorn is an undesirable food source, and also due to the increased prevalence of coyotes. Research shows that deer fawns are a relatively common food item for Chicago-area coyotes. Both Magle and Sacerdote-Velat agree that these findings are significant. The studies demonstrate how the high-density prevalence of this non-native plant is shifting population dynamics and negatively impacting a variety of native animal populations. They suggest land owners and managers should consider invasive species management and habitat restoration. In
some areas, like Lake County Forest Preserve District where Sacerdote-Velat works regularly,
ecologists and land managers have been committed to removing buckthorn from the area. "I hope that this new research will encourage other regions and land managers to take swift and decisive action to work to remove this invasive plant," she said.

Tuesday, April 30, 2013

A new squamate phylogeny

This new study finds rubber boas are not erycines but more closely related to Ungaliophis.
Lizards and snakes (living squamates) number about 9,400 known species. Despite Squamata being one of the most diverse and conspicuous radiations of terrestrial vertebrates, no studies have attempted to reconstruct a phylogeny for the group with large-scale taxon sampling. Such an estimate is invaluable for comparative evolutionary studies, and to address their classification. Alexander Pyron and colleagues (2013) present the first large-scale phylogenetic estimate for Squamata.

Their estimated phylogeny contains 4161 species, representing all currently recognized families and subfamilies. The analysis is based on up to 12896 base pairs of sequence data per species (average = 2497 bp) from 12 genes, including seven nuclear loci (BDNF, c-mos, NT3, PDC, R35, RAG-1, and RAG-2), and five mitochondrial genes (12S, 16S, cytochrome b, ND2, and ND4). The tree provides important confirmation for recent estimates of higher-level squamate phylogeny based on molecular data (but with more limited taxon sampling), estimates that are very different from previous morphology-based hypotheses. The tree also includes many relationships that differ from previous molecular estimates and many that differ from traditional taxonomy.

This study provides a phylogenetic estimate for 4161 squamate species, based on a supermatrix approach. The results provide important confirmation for previous studies based on more limited taxon sampling, and reveal new relationships at the level of families, genera, and species. The authors also provide a phylogenetic framework for future comparative studies, with a large-scale tree including a common set of estimated branch lengths. Also provided is a revised classification for squamates based on this tree, including changes in the higher-level taxonomy of gymnophthalmid and scincid lizards and boid, colubrid, and lamprophiid

Some of the more interesting relationships suggested by this work include the following.

(1) The authors found strong support for the basal squamate relationships in the tree. The family Dibamidae is the sister group to all other squamates, and Gekkota is the sister group to all squamates excluding Dibamidae as in some previous studies. The results also corroborate that the New World genus Anelytropsis is nested within the Old World genus Dibamus, but the associated branches are weakly supported.

(2) Within Gekkota, they corroborate both earlier morphological and recent molecular estimates in supporting a clade containing the Australian radiation of "diplodactylid" geckos (Carphodactylidae + Diplodactylidae) and the snakelike pygopodids. As in previous studies, Carphodactylidae is the weakly supported sister group to Pygopodidae, and this strongly supported clade is the sister group to Diplodactylidae. They recover clades within the former Gekkonidae that correspond to the strongly supported families Eublepharidae, Sphaerodactylidae, Phyllodactylidae, and Gekkonidae as in previous studies.

(3) They found find strong support for monophyly of Toxicofera (Anguimorpha, Iguania, and Serpentes), and moderate support for a sister-group relationship between Iguania and Anguimorpha. Relationships among Anguimorpha, Iguania, and they also corroborate previous studies placing Anguimorpha with Iguania.

(4) The more advanced snakes (alethinophidians) showed a mixture of strongly and weakly supported nodes. The authors found strong support for a clade containing Anomochilidae + Cylindrophiidae + Uropeltidae. This clade of three families is strongly supported as the sister taxon to Xenopeltidae + (Loxocemidae + Pythonidae). Together, these six families form a strongly supported clade that is weakly supported as the sister group to the strongly supported clade of Boidae + Calabariidae.

(5) As for the Pythonidae, the genus Python is the sister group to all other genera. Some species traditionally referred to as Python (P. reticulatus and P. timoriensis) are instead sister to an Australasian clade consisting of Antaresia, Apodora, Aspidites, Bothrochilus, Leiopython, Liasis, and Morelia. These taxa (P. reticulatus and P. timoriensis) have been referred to as Broghammerus, a name originating from an act of "taxonomic vandalism" (i.e. an apparently intentional attempt to disrupt stable taxonomy) in a non-peer reviewed organ without data or analyses. The authors suggest this name should be ignored and replaced with a suitable substitute.

(6) Within Boidae this study and other recent studies have converged on estimated relationships that are generally similar to each other but which differ from traditional taxonomy. However, the classification has yet to be modified to reflect this, and we rectify this situation here. The authors found that Calabariidae is nested within Boidae, but this is poorly supported, and contrary to most previous studies. While Calabaria has been classified as an erycine boid in the past, this placement is strongly rejected by this work and other studies. If the current placement of Calabaria is supported in the future, it would require recognition as the subfamily Calabariinae. The Malagasy boine genera Acrantophis and Sanzinia are placed as the sister taxa to a weakly-supported clade containing Calabariidae and a strongly supported clade comprising the currently recognized subfamilies Erycinae, Ungaliophiinae, and other boines . Regardless of the position of Calabariidae, this placement of Malagasy boines renders Boinae paraphyletic. The authors therefore resurrect the subfamily Sanziniinae for Acrantophis and Sanzinia. This subfamily could be recognized as a distinct family if future studies also support placement of this clade as distinct from other Boidae + Calabariidae.

(7) The genera Lichanura and Charina are currently classified as erycines , but are strongly supported as the sister group to Ungaliophiinae, as in previous studies . The authors expand Ungaliophiinae to include these two genera, rather than erect a new subfamily for these taxa. The subfamily Ungaliophiinae is placed as the sister group to a well-supported clade containing the rest of the traditionally recognized Erycinae and Boinae. And, they restrict Erycinae to the Old World genus Eryx.

An early version of the entire article is available on-line.

Pyron, A. R., F. T. Burbrink, & J.J. Wiens, 2013. A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC Evolutionary Biology 2013, 13:93 doi:10.1186/1471-2148-13-93.

Monday, April 29, 2013

Correlations between habitat use and morphology in sea kraits

Laticauda colubrina. JCM

In a forthcoming article in the Journal of Zoology Wang et al. (2013) report on the variation of characters in three species of Laticauda at Orchid Island, Taiwan. Previous research revealed that the phylogenetic and taxonomic status of the laticaudine sea kraits had been widely discussed in the literature. They found all three species are amphibious, but they differ in their tendency to spend time in marine or terrestrial environments. These sympatric sea kraits are most conspicuous in coastal areas where they tend to be most active at night. Laticauda semifasciata tends to remain submerged in shallow coastal waters; L. laticaudata largely stay above water, but not far from the edge of the sea and L. colubrina exhibit a greater tendency to emerge from water and move farther away from it. Thus, the tendency toward more completely marine habits is highest in L. semifasciata, lowest in L. colubrina and intermediate in L. laticaudata. The authors test the hypothesis that such a species gradient in behavior should be correlated with parallel adjustments in morphological and physiological character states.

All three species move into coastal areas at night. Generally, Laticauda semifasciata remain submerged in sea water, L. laticaudata emerge onto land, but remain not far from the water’s edge, and L. colubrina tend to move farther inland away from the water. They measured parameters of the body shape, vascular lung, saccular lung and hematocrit of sea kraits to investigate possible morphological correlates of their physiology. The most aquatic species, L. semifasciata, had a significantly more laterally flattened body form, larger saccular lung volume and higher hematocrit than the other two species, whereas only few differences were found between the two less aquatic species. L. laticaudata had a significantly higher hematocrit than L. colubrina.

Wang, S., Lillywhite, H. B., Cheng, Y. C. and Tu, M. C. (2013), Variation of traits and habitat use in three species of sea kraits in Taiwan. Journal of Zoology, 290: 19–26. doi: 10.1111/jzo.12012

Saturday, April 27, 2013

Northern Broad-headed snake ecology

Hoplocephalus bungaroides. Photo from Wikipedia

Conservation of highly specialized animals require detailed information on habitat use, dispersal and movement patterns. This kind of data often is often difficult to gather, especially for endangered species because the animals are rare, and because research methods cannot further endanger the species. As a result,  knowledge of many endangered taxa is based on studies performed at only a single site where the species is abundant and easily observed. These kind of sites are atypical of conditions that pertain over most of the species’ range.

One such species is the broad-headed snake (Hoplocephalus bungaroides), an elapid that has drastically declined since European settlement of Australia. Broad-headed snakes rely on  habitat with specific features: they shelter beneath thin, sun-exposed exfoliated rocks on sandstone rock outcrops with western or north-western aspects. These retreat sites allow snakes to thermoregulate during winter and spring. Hoplocephalus bungaroides also exhibit life history traits that render them vulnerable to disturbance: they depend on high rates of adult survival;  breed only every 3 to 4 years; have low fecundity, 3 to 4 offspring per litter; they may take six years to mature; low rates of dispersal; and a small geographic range. All of these traits contribute to the endangered status of broad-headed snake. The habitat of H. bungaroides has become fragmented, and subject to vegetation overgrowth and removal of shelter-sites (exfoliated rock) for landscaping and gardening.

Genetic data show that the intensively-studied southern population belongs to a genetically distinct clade, with another isolated, evolutionarily significant unit identified in the north of the species range. Those two clades diverged approximately 800 000 years ago. Vegetation, temperatures and potential prey species differ between the northern and southern parts of the species’ range.

In a recently published paper, Croak et al. (2013) captured and radio-tracked 9 adult broad-headed snakes at sites in the northern part of the species’ distribution, to evaluate the generality of results from prior studies most of which had been conducted at a southern study site. The authors identify critical habitat components for this northern population. They found snakes spent most of winter beneath sun-warmed rocks then shifted to tree hollows in summer. Thermal regimes within retreat-sites support the hypothesis that this shift is thermally driven. Intervals between successive displacements were longer than in the southern snakes but dispersal distances per move and home ranges were similar. The northern snakes showed non-random preferences both in terms of macrohabitat by avoiding of some vegetation types and selecting microhabitats, that is th  hollow-bearing trees. Despite many consistencies, the ecology of this species differs enough between southern and northern extremes of its range that managers need to incorporate information on local features to most effectively conserve this threatened reptile.

Croak BM, Crowther MS, Webb JK, Shine R (2013) Movements and Habitat Use of an Endangered Snake, Hoplocephalus bungaroides (Elapidae): Implications for Conservation. PLoS ONE 8(4): e61711. doi:10.1371/journal.pone.0061711.

Friday, April 19, 2013

A new cat-eyed snake from India

The nocturnal, arboreal, rear-fanged colubrine snake genus Boiga (the cat-eyed snakes) is represented in Peninsular India by six species:  B. trigonataB. forsteniB. ceylonensisB. nuchalisB. dightoni and B. beddomei. Of these, the last four are characteristic of the wet hill-forest tracts of India’s Western Ghats, and, in the case of B. ceylonensis and B. beddomei, the wet-zone of central, hilly Sri Lanka as well.

Boiga flaviviridis from Kaigal, India. Photo Ashok Captain. 
In a recent paper Vogel and Ganesh (2013) describe a new species of cat snake, related to Boiga beddomei. The new species Boiga flaviviridis from the dry forests of eastern Peninsular India. It occupies a large geographic range from Berhampore, near the River Mahanadi in the northeast to Kaigal near the southern Eastern Ghats in the southwest. Boiga flaviviridis is diagnosed by having 19 dorsal scale rows at mid-body, a high number of ventral scales for the genus Boiga (248–259), a yellowish-green dorsal coloration with numerous faint black bands, an uniform, un-patterned yellow-colored venter and a relatively short tail (18-20% of the total length).

Vogel G. & S.R. Ganesh (2013) A new species of cat snake (Reptilia: Serpentes: Colubridae: Boiga) from dry forests of eastern Peninsular India. Zootaxa 3637:158-168.

Treeboa Ecomorphology

Neotropical treeboas (Corallus) form a monophyletic group of nine species distributed from south-eastern Guatemala to southeastern Brazil They occur on continental and oceanic islands and at elevations between sea level and about 1000 asl. All are moderately sized, with body lengths that are about 1.0–2.0 m, are relatively slender with laterally compressed bodies, thin necks, and large heads. They also have long, recurved teeth on the anterior portions of the maxilla and mandibles. As the common name suggests, they are arboreal and occur in forested habitats ranging from arid Acacia scrub
to primary rainforest, in mangrove swamps, fruit orchards, along gallery forests and riparian zones in Brazilian cerrado and caatinga, as well as urban and suburban situations where they will sometimes seek shelter in human dwellings. Prey is encountered during the night via active and ambush foraging, with some species employing both strategies.

Treeboa diets are largely comprised of lizards, birds, marsupials, rodents, and/or bats; prey is killed by constriction and, like all snakes, they are gape-limited. Several species undergo ontogenetic shifts in diet (e.g. lizards to rodents), some feed on birds and mammals, and others are stenophagic for mammals as adults.

In a forthcoming paper, Henderson et al. (2013) conducted the first study of morphology and diet that considers all nine treeboa species. Using adult specimens from museum collections, they examined several morphometric and meristic variables and their possible relationship to Corallus diets.

They found three basic morphologies within the genus: (1) a short, narrow head and a slender body (C. cookii, C. grenadensis, C. hortulanus, and C. ruschenbergerii), useful for exploiting a wide variety of prey (2) a relatively stout body with a long, wide head (C. batesii, C. caninus, and C. cropanii) associated with feeding on large mammals; and (3) an intermediate morphology, found in C. annulatus and C. blombergii, which may be indicative of endotherm generalists. These morphological and dietary patterns exhibit a strong degree of congruence with a recent molecular phylogeny of Corallus and highlight a heretofore unexamined ecological diversification within Corallus.

Henderson, R. W., M. J. Pauers, and T. J. Colston. 2013. On the congruence of morphology, trophic ecology, and phylogeny in Neotropical treeboas (Squamata: Boidae: Corallus). Biological Journal of the Linnean Society.

Monday, April 15, 2013

A new technology to deal with envenomation

Engineers at the University of California, San Diego have invented
a "nanosponge" capable of safely removing a broad class of 
dangerous toxins from the bloodstream, including toxins produced
 by MRSA, E. Coli, poisonous snakes and bees. The nanosponges 
are made of a biocompatible polymer core wrapped in a natural red
 blood cell membrane. Credit: Zhang Research Lab.
The only effective technology for dealing with envenomation from snakes has been the traditional use of antitoxins produced in a horse or a sheep. This technology was based upon observations made by Henry Sewall, at the University of Michigan in 1887. There now appears to be new technology on the horizon for removing toxins from the blood.

Engineers at the University of California, San Diego have invented a "nanosponge" capable of safely removing a broad class of dangerous toxins from the bloodstream – including toxins produced by MRSA, E. coli, poisonous snakes and bees. These nanosponges, which thus far have been studied in mice, can neutralize "pore-forming toxins," which destroy cells by poking holes in their cell membranes. Unlike other anti-toxin platforms that need to be custom synthesized for individual toxin type, the nanosponges can absorb different pore-forming toxins regardless of their molecular structures. In a study against alpha-haemolysin toxin from MRSA, pre-innoculation with nanosponges enabled 89 percent of mice to survive lethal doses. Administering nanosponges after the lethal dose led to 44 percent survival.

The team, led by nanoengineers at the UC San Diego Jacobs School of Engineering, published the findings in Nature Nanotechnology April 14.

"This is a new way to remove toxins from the bloodstream," said Liangfang Zhang, a nanoengineering professor at the UC San Diego Jacobs School of Engineering and the senior author on the study. "Instead of creating specific treatments for individual toxins, we are developing a platform that can neutralize toxins caused by a wide range of pathogens, including MRSA and other antibiotic resistant bacteria," said Zhang. The work could also lead to non-species-specific therapies for venomous snake bites and bee stings, which would make it more likely that health care providers or at-risk individuals will have life-saving treatments available when they need them most.

The researchers are aiming to translate this work into approved therapies. "One of the first applications we are aiming for would be an anti-virulence treatment for MRSA. That's why we studied one of the most virulent toxins from MRSA in our experiments," said "Jack" Che-Ming Hu, the first author on the paper. Hu, now a post-doctoral researcher in Zhang's lab, earned his Ph.D. in bioengineering from UC San Diego in 2011.

Aspects of this work will be presented April 18 at Research Expo, the annual graduate student research and networking event of the UC San Diego Jacobs School of Engineering.

In order to evade the immune system and remain in circulation in the bloodstream, the nanosponges are wrapped in red blood cell membranes. This red blood cell cloaking technology was developed in Liangfang Zhang's lab at UC San Diego. The researchers previously demonstrated that nanoparticles disguised as red blood cells could be used to deliver cancer-fighting drugs directly to a tumor. Zhang also has a faculty appointment at the UC San Diego Moores Cancer Center.

Red blood cells are one of the primary targets of pore-forming toxins. When a group of toxins all puncture the same cell, forming a pore, uncontrolled ions rush in and the cell dies.

The nanosponges look like red blood cells, and therefore serve as red blood cell decoys that collect the toxins. The nanosponges absorb damaging toxins and divert them away from their cellular targets. The nanosponges had a half-life of 40 hours in the researchers' experiments in mice. Eventually the liver safely metabolized both the nanosponges and the sequestered toxins, with the liver incurring no discernible damage.
Each nanosponge has a diameter of approximately 85 nanometers and is made of a biocompatible polymer core wrapped in segments of red blood cells membranes.

Zhang's team separates the red blood cells from a small sample of blood using a centrifuge and then puts the cells into a solution that causes them to swell and burst, releasing hemoglobin and leaving RBC skins behind. The skins are then mixed with the ball-shaped nanoparticles until they are coated with a red blood cell membrane.

Just one red blood cell membrane can make thousands of nanosponges, which are 3,000 times smaller than a red blood cell. With a single dose, this army of nanosponges floods the blood stream, outnumbering red blood cells and intercepting toxins.

Based on test-tube experiments, the number of toxins each nanosponge could absorb depended on the toxin. For example, approximately 85 alpha-haemolysin toxin produced by MRSA, 30 stretpolysin-O toxins and 850 melittin monomoers, which are part of bee venom.

In mice, administering nanosponges and alpha-haemolysin toxin simultaneously at a toxin-to-nanosponge ratio of 70:1 neutralized the toxins and caused no discernible damage.

One next step, the researchers say, is to pursue clinical trials.

Che-Ming J. Hu, Ronnie H. Fang, Jonathan Copp, Brian T. Luk, Liangfang Zhang. A biomimetic nanosponge that absorbs pore-forming toxins. Nature Nanotechnology, 2013; DOI: 10.1038/nnano.2013.54

Sunday, April 14, 2013

Ripples in the ecosystem

Humans have been moving animals around the planet for thousands of years. Hunter and gathers took dogs with them as they migrated, and with the evolution of agriculture soon other domesticated animals were traded between populations. Like all animals, human alter the environments they live-in and so do their commensal species. But humans are special in that they can move quite large animals around unintentionally, bring together species that have not co-evolved and setting the stage for long term changes in ecosystems.

In 2012 Rogers et al. described the first landscape level natural experiment showing the impact of bird loss on the control of their prey, spiders, and the magnitude of effects generated from long-term, landscape-scale bird loss to the effects generated from bird exclusion experiments elsewhere.

They took advantage of the only place in the world where all avian insectivores have been extirpated from the landscape, the Western Pacific island of Guam. The brown tree snake, Boiga irregularis, was introduced to Guam in the mid-1940's. The snakes ate their way through the bird fauna, leading to the extirpation of all native insectivorous bird species from the majority of the island in the mid-1980's. There are only two insectivorous bird species remaining today, in extremely localized populations; the Micronesian Starling has a small population on Andersen Air Force Base at the northern tip of Guam and the Mariana Swiftlet inhabits three caves on the Naval Base in southern Guam. No non-native insectivorous bird species have colonized the forests of Guam, therefore, aside from these two locations on the military bases, the forests are devoid of insectivorous birds.

Rogers and colleagues focused on spiders because experimental studies showed a consistent top-down effect of birds on spiders. They conducted spider web surveys in native forest on Guam and three nearby islands with healthy bird populations. They found spider web densities on Guam were 40 times greater than densities on islands with birds during the wet season, and 2.3 times greater during the dry season.

The results confirm the general trend from manipulative experiments conducted in other systems however, the effect size was much greater in this natural experiment than in most manipulative experiments. In addition, bird loss appears to have removed the seasonality of spider webs and led to larger webs in at least one spider species in the forests of Guam than on nearby islands with birds.The results suggest that effect sizes from smaller-scale experimental studies may significantly underestimate the impact of bird loss on spider density as demonstrated by this large-scale natural experiment.

However, changes in spider populations are not the only impact of bird loss on Guam. Spider-eating birds were decimated by the brown tree snake, but so were fruit eating birds that disperse seeds. McConkey and colleagues (2012) note that seed dispersal interacts decisively with the major drivers of biodiversity change: habitat fragmentation, over-harvesting, biological invasions, and climate change.

So, Guam’s forests are not only exceptionally quiet due to the loss of birds, but they are also thinning out. A four year study planned for this summer will examine the island for 16 tree species, looking at how the loss of seed dispersing birds, is affecting tree distribution.

While the brown tree snakes have been in Guam for almost 75 years, the presence of invasive constrictors in the Florida Everglades is more recent, probably less than 30 years. So, the Everglades, like Guam, will likely become a laboratory for studying the impact of invasive snakes on the ecosystem.

Martin, C. 2013. Where have the trees of Guam gone?

McConkey, K.R., S. Prasad, R. T. Corlett, A. Campos-Arceiz, J. F. Brodie, H. Rogers, & L. Santamaria, 2012. Seed dispersal in changing landscapes, Biological Conservation, 146, 1-13

Rogers H, J. Hille Ris Lambers, R. Miller, & J.J. Tewksbury (2012) ‘Natural experiment’ Demonstrates Top-Down Control of Spiders by Birds on a Landscape Level. PLoS ONE 7(9): e43446. doi:10.1371/journal.pone.0043446

Wednesday, April 10, 2013

Suzio Report Winter-Spring 2013

Howdy Herpers,                             13 April 2013

It is hoped that your inboxes have not been overtly cluttered with Suizo Reports of late?

Truth be told, a few months ago, I got in a bit of hot water at work when a hacker got into my company computer, and merrily bounced about 250,000 messages into cyberspace over the course of 24 hours. This did nothing to endear me to those who mind our server, not to mention those who sign my paycheck. There was no small measure of irritability directed at my person. My patented method of hang dog looks and blatant apologies did little to assuage their verbal onslaughts. And my highly effective foot-kissing technique was thwarted by feet that were doing the river dance. I’m not limber or fast enough to keep up with uncooperative foot apparel.

The whole incident caused a not entirely irrational fear of mass email missives to well up inside of typing boy here. That fear still manifests itself in every fiber of my being. Every time that I pull the trigger, I hear footsteps. They are Gestapo-like footsteps clomping down the hallway to get me.

But dammit, herp studies come, and herp studies go­and there will never be one like that in the Suizos. Who will ever do such a thing again? Twelve continuous years of radio telemetry on multiple species of venomous reptiles on one patch of ground?  Are you kidding me? No way! It has never happened before, and it will never happen again.

And now that spring is upon us, it’s showtime! For the herps, and for those of us who love them. Let’s rock!

The best place to start anew with these reports is January of this year. Normally, when discussing herp activity in January of any given year, there isn’t much to say. But there were two events that astonished even me.

The first event was one of our tiger rattlesnakes--a male, CT11, “Steven” to be specific. In late October of 2012, Steven moved into a north facing crevice and joined his lady tiger, one that he had dogged all summer long. His crack mate was CT12, “Ellie.” They both remained visible in the crevice throughout the fall of 2012 and early winter of 2013. He was always up front, but shifting around some, while she remained motionless about 300mm behind him­as if glued in place. On 19 January, Steven was viewed and photographed stretched out lengthwise in front of the crevice. Even though he was less than 300mm away from Ellie, his body temperature was 6 degrees C warmer than hers. That apparently was enough to set him motion, for he moved over 50 meters during the next week, implanting himself in the same major boulder stack where he had spent the winter of 2011-2012. We haven’t seen him since, and it may be another month before we do. A 50 meter move by a winter-dormant species like a tiger rattlesnake? Why did he leave his girlfriend behind? Was she a bitch, or what?

The second cool event to occur in January involved a black-tailed rattlesnake pairing­in the dead of winter. In this case, it was CM10, “Susan,” and our as yet un-named big guy, CM12. Susan moved into the same site that she had occupied during the winter of 2011-2012 in November of 2012. Fidelity to hibernacula is old news with Crotalids, so there was nothing new there. But she up and moved ~15 meters between 27 January and 2 February. She crawled under the same boulder that CM12 was occupying. In other words­she joined him! If we’ve learned anything with our study through the past 12 years, it is that it isn’t always the males that do the chasing.

While we’re on the subject of Susan joining our big guy, it should be reported that she has been dogging him this spring. Like our tiger Steven, he seems to be trying to get away from his girlfriend as well. And she keeps popping at sites that he has occupied the week before. What’s up with that? On top of all that, Susan went through a transmitter change recently. During the process, Dale DeNardo detected six follicles in her ovary. She is quite pregnant. She was visited by three different males that we know of last summer/fall, but CM12 was with her the longest. Is “papa” truly trying to get away from her, or leading her to food sources? We can only speculate.

We had a very peculiar winter weather-wise. In both January and February, we would set record lows one week, and record highs the next. Even during the warm weeks, the nights were cold. We have received an estimated 3.0 inches of rain thus far this year. There has been but a limited flower show out our way, for the rains came too late to set up anything spectacular. The strange weather has also set up a leisurely egress with our study animals.

We began the year with 14 rattlesnakes with transmitters. We have one female western diamond-backed rattlesnake (Crotalus atrox), CA133.  We have six tiger rattlesnakes (Crotalus tigris), 3 males (CT10, CT11, and CT14), and 3 females (CT8, CT12, and CT13). And we have seven black-tailed rattlesnakes, 4 males (CM11, CM12, CM14 and CM16) and 3 females (CM10, CM15 and CM17).

We can easily start mowing down what the animals are doing by zeroing in on the tiger rattlesnakes first. Other than Steven’s escape from Ellie, they haven’t done much this year. As reported last fall, male CT14, AKA “Rhino K12,” jetted to the third highest peak of the Suizo Mountains proper, and has remained buried in a vertical cliff face ever since. We hope for movement, but I’ll bet he stays there until May. CT10, “Jeff,” has buried himself under a big gneiss boulder, not so much as a glimpse of him yet. Our longest running tiger, female CT8 “Zona” overwintered in the same rock shelf that she spent the winter of 2009-2010. She has just now begun to bask at the entrance. Ellie must have tired of her own bitching reverberating around her lonely crevice, and has made two minor moves. And female CT13, no name yet, has slipped from her caprock hibernaculum and dropped downslope about 5 meters. Tigers are very boring snakes in the winter, but we did have the benefit of seeing two of them all winter long.

Our lone atrox, CA133, affectionately dubbed “Slone’s bitch,” finally moved from her hibernaculum of a man-made boulder pile at the top of the front range of the Suizos proper. She was last tracked at the base of the same front range, and I expect she will be in Suizo Wash with the next tracking episode. She gave birth the previous two consecutive years­six young in 2011, and four in 2012. It is my extreme hope that she can skip a year, and regain some mass.

It was an off year for all nine of the atrox dens on our hill. We have been keeping our hands off these dens for two years now, in hopes that our lack of attention will benefit them. The short story is that only two atrox were viewed at AD1, four at AD7, and only one at AD8. This is the first year in the history of our study that dens AD4 and AD5 were unoccupied. The same story can be told for atrox dens on other hills under my watch. Thus far this year, I have racked up the pathetic total of 15 atrox. In years past, I’d routinely see twice that many--in one day! I’m not sure what to make of this­except to express the hopes that the downturn is temporary. It is worth mentioning that 2012 as a whole was a down year for this species of snake as well.

The black-tailed rattlesnakes have been nothing short of spectacular. This will be our first year ever of watching this species with any sort of N to back our observations. We are in awe of these impressive beasts, and hope to get some more into the study. The best way to tackle them on an individual basis is to lump them by the vast geographical differences of the terrain they have chosen to occupy. All seven were found near or on Iron Mine Hill, but only three of them remained there for the winter.

CM10, Susan, and her boyfriend CM12, the big guy, both remained on Iron Mine Hill. The only other molossus to remain on the hill this winter was CM16­a young male that “volunteered” for our study last fall. Since CM10 and CM12 each have a full year of observations on them, we know what to expect. But CM16 is new to us. The most remarkable feat he has done thus far is to find a hibernaculum that kept him consistently anywhere from 10 to 15 degrees C warmer than the all 13 snakes under watch. I wonder if there are any breaths of hot air under our little hill? (There are certainly plenty above it!) It is also possible that his transmitter is blipping off inaccurate readings.

Taking the remaining four molossus by number, we first discuss our male CM11, “Gus.” Gus does not let any grass grow under his belly. He is always on the move, and was viewed basking in direct sun several times this winter­the only snake to do this consistently this year. He over-wintered 2 kilometers away from some of his summer haunts, and is now bombing back toward Iron Mine Hill. The term “over wintered” was deliberately used here­as I don’t believe that he actually hibernated. Gus is a shaker!

Next is male CM14, “Marty the prick.” He earned his inappropriate moniker by first being named after his captor, and then constantly shifting from one side of Iron Mine Hill to the other during the summer. This can cause endless consternation and cussing when trying to set up tracking routes. And then he also took off for distant parts last fall. But unlike Gus, he did indeed hibernate­or at least stayed put for three months. He is now also on the move, and I almost dread where he will take us next.

Despite being a hard guy to stay on top of, in late August of 2012, Marty the prick led us to one of the delights of our plot­female CM15. With big, beautiful black doll eyes, and stunning greens and cream pattern, she is the prettiest molossus on our plot. Thus far under our watch, she hung around the eastern slopes of Iron Mine Hill, and then jetted over to the Suizo Mountains proper to hibernate. She emerged in mid-March, only to stake out under the escarpment of a small, flat rock for the next three weeks.  It is expected she will start slipping back toward Suizo Wash soon.

Good old Gus led us to the last, and possibly most-likely-to-succeed molossus on our plot. Female CM17, “Ms. Gus,” was found in love’s embrace with Gus by Marty on 5 October 2012. Being the hopeless romantics that we are, we let them spend the night together, and captured Ms. Gus the next morning. She is one fat, healthy snake, and we expect that Gus is quite the potent dude. We expect Ms. Gus to drop some kids for us this year. We have not had the chance to gather much data on her yet, but I expect she will be another east side of Iron Mine Hill to Suizo Mountains proper kind of snake.

This spring has brought several other thrills our way. Our trips to the Suizo Mountains proper have thus far netted us two juvenile collared lizards. They are only rarely seen on Iron Mine Hill, but seem to have a good population in the Suizos proper. We hope to catch some adult action with them with our tracking duties ahead. We have also seen two young regal horned lizards, and six Gila Monsters. A highlight related to them occurred on 30 March. I looked into their communal denning hole, and came face-to-face with a ringtail. Thus far, our communal Gila Hole has been utilized by 12 Gila Monsters, 2 atrox, a tortoise, and now, the ringtail. I sure do wish that I had attempted a photo of that!

My apologies for the length of this report. I considered those readers who actually pay attention to these writings (both of you) in the preparation. Future reports will contain info on any or all of these rattlesnakes, and you may wish to keep this report to refer back to better understand who is who. From this point on, you will all just be getting numbers and names.

And, with future reports, I’m going to start making fun of people again. Ineptness on my part or that of others will be dealt with mercilessly.

It is now time to go to images. Refer to the text above if you want the long story.

Image01, Feldner: Male CT11 “Steven,” getting ready to leave CT12, Ellie, 19 January 2013

Image02, Feldner: Female CT8, “Zona” basking in front of her hibernaculum. 29 March 2013

Image03, Feldner: Female CM10, “Susan.” Our first good look at her this year. Note the heft toward the rear. 3 March 2013.

Image04, Feldner: Male CM12, Susan’s hibernating buddy. 11 March 2013.

Image05, Feldner: Male CM11 “Gus” basking in sun, 2 March 2013.

Image06, Feldner: Female CM15 emerging from her hibernaculum, 2 March 2013.

Image07, Feldner: Young male CM16, also just coming out of hibernation, 30 March 2013.

Image08, Feldner: Female CM17, “Ms. Gus.” Note the heft toward the rear. Two pregnant molossus? 29 March 2013.

Image09, Repp: Unknown atrox basking on the apron of AD1. 17 March 2013.

Image 10,Feldner: One of two young regal horned lizards seen thus far this year. 30 March 2013.

Image11, Repp: Female HS21, processed, pit tagged, and released 30 March 2013. She kind of stands out like goat turds in the milking pail, doesn’t she?

Image 12, Repp: Female HS21, close up. Fat, ain’t she? 30 March 2013.

Image 13, Feldner: Nice shot Marty! One of two collared lizards observed in the Suizo Mountains proper this year. 13 March 2013.

Image14, Feldner: We take what happens after the tracking much more serious than the tracking itself. This image will give you a small taste of what it is I’m talking about.

Many thanks to all of you who have made this all possible, both with your monetary contributions, and your sweat equity. We earnestly look forward to whatever comes next.

This here is Roger Repp, signing off from Southern Arizona, where the turtles are strong, the snakes are handsome, and the lizards are all above average.

Organic matter recovered from Early Jurassic dinosaur

Semitransparent flesh reconstruction of embryonic dinosaur
 inside egg, with skeleton (artwork by D. Mazierski).
A 190-million-year-old dinosaur bone bed near the city of Lufeng, in Yunnan, China has revealed for the first time how dinosaur embryos grew and developed in their eggs.

The great age of the embryos is unusual because almost all known dinosaur embryos are from the Cretaceous Period. The Cretaceous ended some 125 million years after the bones at the Lufeng site were buried and fossilized.

Led by University of Toronto Mississauga paleontologist Robert Reisz, an international team of scientists from Canada, Taiwan, the People’s Republic of China, Australia and Germany excavated and analyzed over 200 bones from individuals at different stages of embryonic development.

“We are opening a new window into the lives of dinosaurs,” says Reisz. “This is the first time we’ve been able to track the growth of embryonic dinosaurs as they developed. Our findings will have a major impact on our understanding of the biology of these animals.”

The bones represent about 20 embryonic individuals of the long-necked sauropodomorph Lufengosaurus, the most common dinosaur in the region during the Early Jurassic period. An adult Lufengosaurus was approximately eight metres long.

The disarticulated bones probably came from several nests containing dinosaurs at various embryonic stages, giving Reisz’s team the rare opportunity to study ongoing growth patterns. Dinosaur embryos are more commonly found in single nests or partial nests, which offer only a snapshot of one developmental stage.

To investigate the dinosaurs’ development, the team concentrated on the largest embryonic bone, the femur. This bone showed a consistently rapid growth rate, doubling in length from 12 to 24 mm as the dinosaurs grew inside their eggs. Reisz says this very fast growth may indicate that sauropodomorphs like Lufengosaurus had a short incubation period.

Reisz’s team found that the femurs were being reshaped even as they were in the egg. Examination of the bones’ anatomy and internal structure showed that as they contracted and pulled on the hard bone tissue, the dinosaurs’ muscles played an active role in changing the shape of the developing femur. “This suggests that dinosaurs, like modern birds, moved around inside their eggs,” says Reisz. “It represents the first evidence of such movement in a dinosaur.”

The Taiwanese members of the team also discovered organic material inside the embryonic bones. Using precisely targeted infrared spectroscopy, they conducted chemical analyses of the dinosaur bone and found evidence of what Reisz says may be collagen fibres. Collagen is a protein characteristically found in bone.

“The bones of ancient animals are transformed to rock during the fossilization process,” says Reisz. “To find remnants of proteins in the embryos is really remarkable, particularly since these specimens are over 100 million years older than other fossils containing similar organic material.”

Only about one square metre of the bone bed has been excavated to date, but this small area also yielded pieces of eggshell, the oldest known for any terrestrial vertebrate. Reisz says this is the first time that even fragments of such delicate dinosaur eggshells, less than 100 microns thick, have been found in good condition.

“A find such as the Lufeng bone bed is extraordinarily rare in the fossil record, and is valuable for both its great age and the opportunity it offers to study dinosaur embryology,” says Reisz. “It greatly enhances our knowledge of how these remarkable animals from the beginning of the Age of Dinosaurs grew.”

Reisz, R.T., T. D. Huang, E. M. Roberts, S.R.Peng, C. Sullivan, K. Stein, A. R. H. LeBlanc, D.B. Shieh, R.S. Chang, C.C. Chiang, C. Yang, S. Zhong. 2013. Embryology of Early Jurassic dinosaur from China with evidence of preserved organic remains. Nature, 496 (7444): 210 DOI: 10.1038/nature11978

Saturday, April 6, 2013

Venom evolution in lizards & snakes

Python bites can produce false positives when
using venom detection kits. JCM

In 2005 it became apparent that venom  first evolved in the ancestor of the the Iguiana Lizards, Anguingmoprh lizards and the snakes. These three clades form a larger clade now known as Toxicofera. In a forthcoming paper Fry et al. (2013)  examine the oral glands in both the upper and lower jaws of the toxicoferans and find they are all involved in making the various molecules found in venom. Even the poorly known rictal glands of snakes make a variety of molecules that are venom components.  Rictal glands were investigated in two studies about 100 years ago. The secretions were shown to be highly toxic to birds but  no  investigations followed up on these glands, until now. Fry and colleagues show the rictal glands are in fact derived from the well-studied venom glands.Suggesting that the secretion of venom by snakes is much more complex than previously thought.

Several other interesting pieces of evidence regarding the evolution of venom were found during this study. Pythons have a novel, low-molecular weight disulphide bridged peptide class. This is the first evidence that pythons are still carrying at least some of the genetic material to make venom, and transcribing those genes. Iguanian lizards maybe using their venom molecules to control microbes. And,  proteins with hemotoxic or neurotoxic activity at low levels occur in iguanian and anguimorph lizards and caenophidian snakes. Even the ‘basal’ snakes (like Cylindrophis) surprisingly were found to express the 3-finger toxin and lectin toxins as the dominant transcripts. Also, in the constricting pythonid and boid snakes, where the glands are predominantly mucous-secreting, low-levels of toxin transcripts can be detected. Venom  appears to play a minimal role in the feeding behavior of most iguanian lizards and constricting snakes, and the low levels of expression argue against a defensive role.

Doctors in Australia rely on the venom detection kit to aid in diagnosis of snake bite. False-positives could lead to patients getting very expensive antivenom they don’t need and  possibly triggering life-threatening allergies and reducing the supply for patients who actually need it. This paper shows a surprising potential source of false-positives: pythons. A previous study showed that pythons cross-react in the Snake Venom Detection Kit (sVDK) but this curious result was dismissed as an anomaly. Fry et al. show that even though python oral glands overwhelmingly secrete mucus to lubricate prey for swallowing, there is still a trace of venom in their oral secretions. The venom is not enough to harm a human or  kill  prey, but enough to confuse an extremely sensitive diagnostic tool like the sVDK. While this poses a problem for doctors and snakebite victims it also provides an opportunity. The low level of ancient venom still secreted in these glands contained novel compounds that were quite different than those from the  well-studied front-fanged snakes like rattlesnakes and  mambas. These novel molecules therefore represent an untapped resource for biodiscovery.

Bryan G. Fry, Eivind A.B. Undheim, Syed A. Ali1, Jordan Debono, Holger Scheib, Tim Ruder, Timothy N. W. Jackson, David Morgenstern, Luke Cadwallader, Darryl Whitehead, Rob Nabuurs, Louise van der Weerd, Nicolas Vidal, Kim Roelants, Iwan Hendrikx, Sandy Pineda Gonzalez, Alun Jones, Glenn F. King, Agostinho Antunes, Kartik Sunagar. 2013. Squeezers and leaf-cutters: differential diversification and degeneration of the venom system in toxicoferan reptiles. Molecular & Cellular Proteomics In press. M112.023143