Monday, December 31, 2012

Suizo Report -- Some Summer and Fall Highlights

Happy New Year Herpers,

I'm going to take a minute to try to persuade some of you to step up for the Tucson Herpetological Society. If any of you have a herp-related presentation of any sort that you would like to give us, please let me know. Currently, we have openings from March 2013 through infinity. We normally offer an honorarium, a free year membership, and a T-shirt or hat.

So, if some of you out of town folk are going to be coming this way any how, please try to time your visits for the third Tuesday of any given month. We likely can't afford travel expenses from far off places, but if you're planning to come to town anyway, why not?


My duties with the THS have made it difficult to send out these reports with any kind of regularity. Many cool things happened this year that I didn't get the chance to share with you all. Now I'm taking the time to make it so.

Image 1: Male Crotalus tigris #10, Jeff, 29 July 2012. I'm showing you this image because I think of it as a "classic" color phase for a tiger. Get a load of the next one.
Image 2, by Steve Ressel: What I call the "Silver Phase Tiger" From Sabino Canyon, 18 July 2012. Sweet!
Image 3: Quoting Dennis Caldwell, as he is aiming his camera at something in the Huachuca Mountains. "I got this fat tree lizard on a rock here--and oh, oh, I think she's about to $hit---Oh--and she did!" 8-)
Image 4: The same day that the tree lizard crapped, (22 July 2012), we found a gorgeous short horned lizard.
Image 5: Still the same trip, a DANDY Madrean Alligator Lizard (posed).
Image 6: John Slone and Marty Feldner led us to a land we dare not speak of to show us many wonders. This sweet little Crotalus cerberus was one such wonder.
Image 7: A Grand Canyon Rattlesnake, from John and Marty land. If I told you where it was, they would have to kill all of us.
Image 8: A Wandering Gartersnake, near the north rim of the Grand Canyon.

Image 9: In late August, the Chicago Herp Society was kind enough to fly me out for a presentation. They were also kind enough to take me herping in Carl Koch-land in Southern Wisconsin. They were NOT kind enough to let me find anything, but at least Gery was able to locate the purpose of the trip-- a  hog-nosed snake. This is a very young snake.
Image 10: Our biggest male Crotalus molossus, CM12. 29 September 2012
Image 11: This is the last image that I will ever get of female Crotalus atrox #121, Tracy. While the image is grainy, it clearly depicts how well these things can blend with their surroundings. But in Tracy's case, not good enough! We found her transmitter on the ground a week later. Bummer!
Image 12: My interest with Iron Mine Hill/Suizo Mountains began with lyresnakes. The crevice that this snake is in contained the third-ever lyresnake found there. It was used regularly from 1993-1995, and then only sporadically after. This image was taken on 22 December 2012--a week ago. I'm hoping to see more of this snake in the days and years ahead.
Image 13: What would a Suizo Report be without our beloved fat head "Gus." Here he is in situ on 22 December 2012.
I'm off to join the Suizo gang tomorrow. My last visit was on 22 December, and things are looking up. We've received close to 2 inches of rain the past two weeks. The annuals are starting to pop out of the ground. Three Gila Monsters can now be seen routinely, and we now have two active lyresnake crevices--one of which contains two snakes. Usually, when a few lyresnakes bask for us, several others will as well. We have three tiger rattlesnakes that can be seen regularly, as well as several atrox and a couple tortoises.

Things are looking up!

Here's hoping that our paths will cross again in 2013. Until that time, happy herping!

Best, roger
others do as well. 

Saturday, December 29, 2012

The White-flanked Malagasy Tree Frog, A New Frog from southern Madagascar

Guibemantis tasifotsy

Mantellid frogs comprises the largest radiation of frogs in Madagascar with 200 know species in 12 genera. Within the family, at least three clades have independently adapted to phytotelmic breeding: Blommersia angolafa, Mantella laevigata, and the subgenus Pandanusicola in the genus Guibemantis. Pandanusicola are small frogs with snout–vent lengths between 20–38 mm that typically reproduce in the leaf axils of Pandanus screw pines: their eggs are deposited on leaves near the water-filled axials, and the exotrophic tadpoles develop within these leaf axial pools. This breeding mode applies to all but one species, Guibemantis liber, which deposits its eggs on leaves overhanging ponds and swamps in which its tadpoles develop. Molecular data suggests a high proportion of undescribed species diversity in Guibemantis, and two recently described  lineages were described as new species in 2011. At present, there are eight nominal species included in the subgenus Pandanusicola. The identity and delimitation of most of these species is well understood; however, G. bicalcaratus, G. liber, and G. pulcher still require revision.

One possible species characterized by a strong molecular divergence to other Pandanusicola, is morphologically intermediate between G. liber and G. pulcher. Surprisingly, this species was collected while calling on vegetation over swamps, suggesting it was not using leaf axials as a mode of reproduction as in G. liber Although the molecular data did not indicate close relationships to this species.

Evidence from morphology, bioacoustics, and mitochondrial genes suggest the species is distinctly different from G. liber as well as from G. pulcher, and consequently Lehtinen et al. (2012) describe it as new species, the White-flanked Malagasy Tree Frog, Guibemantis tasifotsy. The new frog is known only from southeastern Madagascar and differs from most Pandanusicola by probably not breeding in leaf axials of Pandanus  but instead probably lays its eggs in open lowland swamps. Newly determined DNA sequences of the cytochrome b gene confirm that G. tasifotsy is genetically highly divergent from all other species of Guibemantis.

Richard M. Lehtinen, Frank Glaw, Franco Andreone, Maciej Pabijan, and Miguel Vences. 2012. A New Species of Putatively Pond Breeding Frog of the Genus Guibemantis from Southeastern Madagascar. Copeia 2012(4):648-662.

Thursday, December 20, 2012

Squamates & the Cretaceous Extinction

The carnivorous lizard Palaeosaniwa stalks a pair of hatchling Edmontosaurus as
 the snake Cerberophis and the lizard Obamadon look on. Obamadon gracilis is
a small polyglyphanodontian named after President Obama. These squamates 
disappeared with the dinosaurs at the Cretaceous extinction.

More than 9,000 living species of snakes and lizards exploit an extraordinary range of ecological niches and habitats. The history of this radiation extends deep into the Mesozoic. After the appearance of crown squamates in the Jurassic, lizards and snakes underwent a Cretaceous radiation, and by the late Cretaceous most major groups had appeared, including iguanians, geckos, skinks, anguids, and platynotans, as well as many lineages of  snakes. The Cretaceous–Paleogene (K-Pg) extinction that ended the Mesozoic and the dinosaurs is considered to have had little effect on squamate evolution with the exception of the marine mosasaurs. And, all major squamate lineages are thought to have survived the end of the Cretaceous. Now a new study by Longrich et al. (2012) suggests otherwise.

A revision of fossil squamates from the Maastrichtian and Paleocene of North America shows that lizards and snakes suffered a devastating mass extinction coinciding with the Chicxulub asteroid impact. Species-level extinction was 83%, and the K-Pg event resulted in the elimination of many groups of lizard groups and a dramatic decrease in morphological disparity. Survival was associated with small body size and perhaps large geographic range. The recovery was longed with diversity not approach Cretaceous levels for 10 million years after the extinction, and it resulted in a dramatic change in faunal composition. 

Nicholas R. Longrich, Bhart-Anjan S. Bhullar, and Jacques A. Gauthier. 2012. Mass extinction of lizards and snakes at the Cretaceous–Paleogene boundary PNAS 2012 ; published ahead of print December 10, 2012, doi:10.1073/pnas.1211526110

The First Known Freshwater Mosasauroid

An artist's drawing of the Pannoniasaurus inexpectatus 
that lived 84 million years ago in freshwater floodplains.
 (Image: Tibor Pecsics)
Until now, mosasauroids have been considered exclusively marine. However, László Makádi from the Hungarian Natural History Museum, and colleagues from the University of Alberta, Canada and MTA-ELTE Lendület Dinosaur Research Group, in Hungary report the discovery and describe Pannoniasaurus a new species having unsuspected adaptations to freshwater ecosystems.

The new mosasaur discovered in Hungary is the first known example of this group of squamate reptiles to have lived in freshwater river environments similar to modern freshwater dolphins.

The species lived about 84 million years ago, the largest specimens reached about 20 feet in length, and belongs to a family called 'mosasaurs', conventionally thought of as gigantic finned marine lizards, similar and perhaps even related to present day monitor lizards. The researchers discovered several fossils of the new species, ranging from small juveniles to large adults that suggest that this species had limbs like a terrestrial lizard, a flattened, crocodile-like skull, and a tail unlike other known members of the mosasaur family.

The fossils were recovered from an open-pit mine in the Bakony Hills of Western Hungary, which were once flood-plains. According to the study, this is the first known mosasaur that lived in freshwater, and only the second specimen of a mosasaur to have been found in rocks that were not once deposited in the ocean. Makadi says, "The evidence we provide here makes it clear that similar to some lineages of cetaceans, mosasaurs quickly adapted to a variety of aquatic environments, with some groups re- invading available niches in freshwater habitats. The size of Pannoniasaurus makes it the largest known predator in the waters of this paleo-environment."

Whether or not Pannoniasaurus was restricted to freshwater environments, or perhaps instead was a seasonal, opportunistic migrant and consumer in these habitats, remains uncertain. Sedimentological, taphonomical, morphological and geochemical evidences suggest the former. In association with the facies analysis and depositional environment interpretations, the collected evidence indicates that Pannoniasaurus is best interpreted as an inhabitant of freshwater ecosystems. Currently, among derived pythonomorphs, Pannoniasaurus, whether being an obligatory freshwater animal or a seasonal or opportunistic migrant, remains the first and only know river-dwelling member of the clade including aigialosaurs and mosasaurs.

Even in the modern world, squamate reptiles in the aquatic world are extremely rare. Only a few species live in the water, and even fewer, like marine iguanas and sea kraits, live in the oceans. The new species described here probably adapted to freshwater environments similarly to river dolphins, such as those now inhabiting the Amazon, Ganges and Yangtze rivers.

The evidence we provide here makes it clear that similar to some lineages of cetaceans, mosasauroids quickly radiated into a variety of aquatic environments, with some groups reinvading available niches in freshwater habitats, and becoming highly specialized within those ecosystems.

László Makádi, Michael W. Caldwell, Attila Ősi. The First Freshwater Mosasauroid (Upper Cretaceous, Hungary) and a New Clade of Basal Mosasauroids. PLoS ONE, 2012; 7 (12): e51781 DOI: 10.1371/journal.pone.0051781

Wednesday, December 19, 2012

Length–mass allometry in snakes

Arboreal, burrowing, and aquatic boids.
Clue's to an animals life style (aquatic or terrestrial, burrowing or arboreal) are related to its body size and mass. Body size and body shape are closely correlated to an animal’s physiology, ecology and life history, and, therefore, play a major role in understanding ecological and evolutionary phenomena. Since many species are known from relatively few specimens or difficult to observe direct observations is not always possible. But, because organisms often have different shapes, only a uniform proxy, such as mass, may be suitable for comparisons between taxa. Snake masses are rarely reported in the literature. On the basis of 423 species of snakes in 10 families, Feldman and Meiri (2013) developed clade-specific equations for the estimation of snake masses from snout–vent lengths and total lengths. They found that snout–vent lengths predict masses better than total lengths. By examining the effects of phylogeny, as well as ecological and life history traits on the relationship between mass and length, they found that viviparous species are heavier than oviparous species, and diurnal species are heavier than nocturnal species. Furthermore, microhabitat preferences profoundly influence body shape: arboreal snakes are lighter than terrestrial snakes, whereas aquatic snakes are heavier than terrestrial snakes of a similar length.

Feldman, A. and S. Meiri. 2013. Length–mass allometry in snakes. Biological Journal of the Linnean Society 108:161-172.

Sunday, December 16, 2012

No evidence for erycine boas in North America before the Miocene

Extant erycine boas: An African  Exyx colubrinus, and the North American  Lichanura, and Charina
The central Rocky Mountain Interior has long been a focus of study for late Eocene early Oligocene fossils in North America. The Medicine Pole Hills of North Dakota has preserved abundant late Eocene fossils which provide a glimpse of the central North American fauna prior to the earliest Oligocene cooling. In a forthcoming article, Smith (2012) reports on the fossil snakes of this locality using 179 isolated vertebrae from all parts of the vertebral column as well as cranial elements. The assemblage comprises four species: (1) a primitive burrowing snake (“anilioid”); (2) a small boid related to Ungaliophiinae (dwarf boas); (3) a mid-sized booid related to Loxocemus (Mexican Burrowing Python); and (4) a colubrid. The dwarf boa, Calamagras weigeli, is conservatively regarded as the earliest secure representative of the clade Ungaliophiinae, but the history of this clade may stretch considerably further back. The loxocemid, Ogmophis compactus, is the second reported fossil from that clade. The colubrid is one of the earliest known and could represent the first appearance of colubrine “racers” in North America; it may have had an elongate tail, implying that it was arboreal, but this is not yet clear. Full-column analysis and cranial elements prove crucial for the accurate higher-level identification of snake clades from which these isolated elements derive.

This paper is of most interest because it clarifies the previous idea that Erycinae boas were common in the Paleogene of North America. Today in North America erycines are represented by the rosy boas (Lichanura) and the rubber boas (Charina). In the past many authors assigned most North American Paleogene snake taxa to the Erycinae (sand boas) Smith reports that there is no well-founded record of an erycine boa in North America prior to the Miocene. The mistake apparently resulted from the similarity of mid-body vertebrae in the extant North American Erycinae and the Paleogene snakes. Thus the Eocene North American snake fauna had small booid snakes, but they were in fact members of the loxocemid and ungaliophid clades, not the Eastern Hemisphere sand boas, the Erycinae.

Smith, K. T. 2012. New constraints on the evolution of the snake clades Ungaliophiinae, Loxocemidae and Colubridae (Serpentes), with comments on the fossil history of erycine boids in North America. Zoologischer Anzeiger - A Journal of Comparative Zoology,

Capuchin monkeys learn to respond or not respond to snakes

Photo credit: Steven G. Johnson
Primates have evolved antipredator behaviors for many potential predators including snakes, crocodiles, caimans, felids, canids, raptors, and other primates. Antipredator behavior includes avoidance, mobbing, alarm calls, vigilance, evasive maneuver/fleeing/seeking refuge, and aggressive behavior based on level of risk.
Young animals are smaller and less experienced than adults and thus may be susceptible to a wider range of predators. This risk should lead to strong selection for the evolution of innate predator recognition yet examples of false alarming (alarming at nonpredators) by young primates suggest that this facet of antipredator behavior likely involves experiential refinement of the predator-recognition process. Studies of vervet monkeys, spectral tarsiers, and white-faced capuchin monkeys show that younger individuals alarm call at a wide range of harmless animals, a behavior rarely found in adults. As the individuals age, they become more selective and restrict alarm calling mainly to dangerous predators.

Meno et al. (2012) examined the influence of the social environment on antipredator behavior in infant, juvenile, and adult wild white-faced capuchin monkeys (Cebus capucinus) at Lomas Barbudal Biological Reserve in Costa Rica. Different species of model snakes and novel models. were presented to the capuchins and the authors examined: (a) the alarm calling behavior of the focal animal when alone versus in the vicinity of conspecific alarm callers and (b) the latency of conspecifics to alarm call once the focal animal alarm called. Focal animals alarm called more when alone than after hearing a conspecific alarm call. No reliable differences were found in the latencies of conspecifics to alarm call based on age or model type. Conspecifics were more likely to alarm call when focal individuals alarm called at snake models than when they alarm called at novel models. Results indicate (a) that alarm calling may serve to attract others to the predator’s location and (b) that learning about specific predators may begin with a generalized response to a wide variety of species, including some nonthreatening ones, that is winnowed down via Pavlovian conditioned inhibition into a response directed toward specific dangerous species. This study reveals that conspecifics play a role in the development of antipredator behavior in white-faced

MENO, W., COSS, R. G. and PERRY, S. (2012), Development of Snake-Directed Antipredator Behavior by Wild White-Faced Capuchin Monkeys: II. Influence of the Social Environment. Am. J. Primatol.. doi: 10.1002/ajp.22109

Monday, December 10, 2012

Origins of the North American Desert Fauna

The Rosy Boa, Lichanura trivirgata.
Phylogeographic studies of the southwestern deserts of North America have suggested diverse historical processes, with two hypotheses posed as most important for shaping genetic structure: climate fluctuations in the Pleistocene and pre-Pleistocene vicariance. Support for the climate fluctuation hypotheses emerged from a historical understanding of Pleistocene vegetation patterns within North American deserts and from the perception that desert floras were relatively young. Environmental reconstructions, based largely on analysis of packrat middens, have suggested that present distributions of the Mojave and northern Sonoran Desert biomes were largely comprised of mesic woodlands during the Last Glacial Maximum (LGM: 18,000−20,000 years ago. Furthermore, these deserts only recently reached their current extents in the present interglacial period Presumably, recent biotic responses of desert habitats to climatic change have also occurred during the repeated glacial/interglacial cycling throughout the Pleistocene (especially over the last 700,000 years. As such, several studies have posited that arid-adapted species spanning multiple deserts would have been limited to isolated refugia within the Mojave and Sonoran Deserts during glacial periods, assuming that niche requirements remained the same over time. Repeated displacement and fragmentation of habitats during climatic fluctuations should have resulted in genetic lineage diversification between refugial populations. Similarly, evidence of demographic expansion within lineages should coincide with the end of the LGM, as desert habitats expanded to maximum distributions.

Wood et al. (2012) investigate the phylogeographic history of the Mojave and Sonoran Deserts using a comparative approach. They examining spatial and temporal patterns of DNA sequence variation in 12 species, and evaluate the concordance of phylogeographic breaks and lineage diversification for both Pleistocene climate fluctuation hypotheses and pre-Pleistocene vicariance hypotheses. And, they used visualization methods to assess the spatial pattern of genetic diversity and divergence across species and identify regional evolutionary hotspots.

In seven of the 12 species, lineage divergence substantially predated the Pleistocene. Historical population expansion was found in eight species, but expansion events postdated the Last Glacial Maximum in only four lineages. For all species assessed, six hotspots of high genetic divergence and diversity were concentrated in the Colorado Desert, along the Colorado River and in the Mojave/Sonoran ecotone. At least some proportion of the land within each recovered hotspot was categorized as protected, yet four of the six also overlapped with major areas of human development.

Eight of the 12 species used were members of the herpetofauna (the red spotted toad, Anaxyrus punctatus the shovel-nosed snake, Chionactus occipitalis; the collared lizard, Crotaphytus bicinctores; the sidewinder, Crotalus cerastes; the rosy boa, Licanura trivirgata; and the horned lizard, Phryanosoma platyrhinos; the spiny lizard, Scleroporus magister; and the night lizard, Xantusia vigilis).

Most of the species examined in this study diversified into distinct Mojave and Sonoran lineages prior to the LGM – supporting the older diversification hypotheses. Several evolutionary hotspots were recovered but are not strategically paired with areas of protected land. Long-term preservation of species-level biodiversity would entail selecting areas for protection in Mojave and Sonoran deeserts to retain divergent genetic diversity and ensure connectedness across environmental gradients.

The entire article is available on-line.

The Beaked Sea Snake, Two Cryptic Species

The deadliest sea snakes in the world can be found from the Arabian Peninsula to Australia. They like to live in estuaries and lagoons near the shore and have been known to get tangled in fishermen's nets and inflict fatal bites. Their venom is extremely toxic, more potent than that of a cobra.

But the deadliest sea snake has a secret — it is actually two sea snake species.
Scientists once thought that snakes in Australia and Asia were the same species, Enhydrina schistosa. The snakes from these regions do look similar, with beaklike mouths that have a notch between the lower jaws.

However, when University of Queensland researcher Bryan Fry and colleagues tested the serpentine DNA, the results showed that they were separate species, and not even close relatives, as noted by the publication Asian Scientist.

This is a case of convergent evolution, wherein different species evolve independently but end up looking quite similar, according to the study, published recently in the journal Molecular Phylogenetics & Evolution. Or, as Yong put it, convergent evolution is "when different species turn up at life's party wearing the same clothes."

Considering that these animals are responsible for the majority of deaths caused by sea snakes, it's important to know the identity of the different species. Luckily, however, the antivenin used to treat bites from the Australian and Asian version of this "species" works on both, according to the study.

Both sea snakes feed almost exclusively on spiny catfish and puffer fishes, which requires the snake to open its jaws very wide. The scientists suggest this is one reason for their similar appearance; the notched jaw allows them to swallow these creatures whole.

The researchers have proposed new names for the sea snakes that will better reflect their evolutionary history. The Asian serpent should retain the name Enhydrina schistosa, they suggest, while the Australian species could be dubbed Enhydrina zweifeli.

Ukuwela, K.D.B., de Silva, A., Mumpuni, Fry, B.G., Lee, M.S.Y., Sanders, K.L., Molecular
evidence that the deadliest sea snake Enhydrina schistosa (Elapidae: Hydrophiinae) consists of two convergent species, Molecular Phylogenetics and Evolution (2012), doi:

Saturday, December 8, 2012

Suizo Report -- 1,834

I find myself in the midst of my own man-made purgatory. We speak of going through my notes and assembling data. Since the year 2000, I find that I have logged over 20,000 lizards. That number seems unbelievable.  But I did something today that makes this number seem trivial by comparison.

I decided to count vehicles on my way to work this morning. This nearly got me killed--twice. So let me pass on some important safety tips to you all. Don't tug on Superman's cape, don't piss in the wind, and don't EVER count vehicles on your way to work.

My daily commute is 25 miles in. I did my counting between 0630 and 0700. I only counted the cars that were coming at me. This despite the fact that the heaviest traffic was going my way.

And how many vehicles did I count? See the number in the subject box.
That's right: One thousand
eight hundred and thirty four. We can easily double that, because as already stated, I didn't count the cars going my way. And it wasn't even close to rush hour yet!

We can conservatively say that 4 thousand people were doing the same thing as I, within a half-hour time span. In five days of driving one way, 1/2 hour per day, I equal my lizard counts over the past 12 years. 2.5 hours driving = 20,000 people. Over 10,000 hours of field work = 20,000 lizards.

I'm a LOT more comfortable with my lizard count now............

As you local herpers know, we're being basted by above average temperatures of late. Surprisingly, the D'backs and tigers all went to their hibernacula a couple of weeks early, and haven't done anything to speak of since.

Not so with the black-tailed rattlesnakes. Most continued to move throughout November, and two appear to be still actively hunting. We go to pictures for the rest of the story:

Image 1: Female CM17, "Ms. Gus," as viewed on 23 November 2012. She is posed under a dead prickly pear umbrella, a spindly hackberry and trixis above her. While this is a protective little cove, it is not a rock structure in any way, shape or form. There is, however, a cliff about 2 meters behind her, with many crevices and tortoise-like burrows for her to retreat.
Image 2: Here is CM17 again, on 4 December 2012. She has only moved about 15 cm from this photo to the previous. It is entirely possible that she is going in and out of one of the openings in the cliff behind her. It is also possible that she is just staying there--which sets up the scenario of a rattlesnake enduring VERY cold nights--close to freezing.

Image 3: Male CM11, "Gus." This image was also taken on 4 December. Note the rat scat around him. I do believe they are still hunting!
I wish we had stayed with black-tails back when we started with them in 2001. But I sure am glad that we finally saw the light, and started tracking them again. I am in awe of these desert molossus!

Changing subjects, snakes unhinging their jaws in order to eat large prey items is a common misconception. In the past, when I was asked about this myth, I was never able to explain it all properly.

Harry Greene was recently filmed explaining the "how" of it all when it comes to feeding snakes. The film is only 8 minutes long, and I HIGHLY recommend that you take the time to watch it. The way he works the kids in this film is exemplary, and the way those kids worked together to bring Harry's lesson to light at the end of it all is downright hysterical!

Click on the link below, and see for yourself. Nice work, Harry!

Best to all, roger

Friday, November 30, 2012

Suizo Report -- Late October and November 2012

Howdy Herpers,                                                                                               11/28/12

The last Suizo rattlesnake roundup to occur in 2011 was a dandy. The effort, which happened in September, brought three very cool snakes into the fold. The first was male Crotalus tigris #11, (CT11) "Steven."  The second was female Crotalus molossus #10, (CM10) "Susan," and male CM11 "Gus." (Although at that point in time, Gus got the PIT tag and ye old unceremonious release. And he was nameless at that point in time. Yes, we were "Gus-less," and had no idea what we were missing. He was recaptured in summer 2012, and did not get off as lightly).

While images of Susan and Gus are contained in this report, today's REAL pre-image soliloquy centers around Steven, and his girlfriend CT12, "Ellie." (Ellie is not her real name--yet. But for the sake of this report, we shall call her that.)

Well--shoot! now I gotta explain how Ellie comes into the story.
These pre-image soliloquies are SO exhausting!

Back in the day before Marty Feldner was performing the actual tracking, he would dog my tracking path and be the PERFECT guest. A perfect guest actually tries to find new herps while others track the known ones. I believe that it was around midnight on a Mid-June night that Marty found Ellie while I was doing a write up on Patti the Gila Monster. Ellie was captured fairly close to Steven's capture spot, but we had not yet figured out how close the bond may be between these two.

But as soon as Ellie was in the game, her first move was to slip into a spot that Steven had occupied about two months previous. That's when I began to sense something cool was going to happen between the two of them. By July, both snakes has shotgunned well out into the bajada south of Iron Mine Hill (IMH). They began to occupy the same sites--but never were both together at the same time. Sometimes, it seemed she was dogging him. At other times, he seemed to be following her. They were seldom more than 20 meters apart. Keeping in mind that we only actually spend about 15 minutes a week on each snake, it is possible-to-likely that they had been together more than once last summer, but we didn't see it.

And then, on the evening of 20 October, by far the coolest tracking incident of the year (where I was the one holding the magic wand) occurred. As I blundered my way up the east slope of IMH, it became clear that the two were once again quite close to each other. But Ellie was the closer of the two. When I tracked her down, it was noted that she was in the EXACT same crevice that Steven had occupied EXACTLY one year before. Cool stuff!

I completed the write up on her, and switched to Steven. The signal indicated that I was now VERY close to him. I had not yet even packed my gear to move when I saw him barrel across the crevice that contained Ellie, and dove in to join her! It is most fortunate that my camera was out for the occasion. For once, I was blessed with the luck of Marty Feldner. To see this pairing as it happened is one thing, to get some hasty images of it happening is the other, and the fact that the pair has remained together since is downright serendipity!

Image 1: Steven jets past me. Bad image, but lucky to have it.

Image 2: Steven sets up shop. Ellie is behind him, and will be impossible to photo without a special burrow camera.
Image 3: A double-tiger crevice, taken November 10. If you look carefully, you will see Steven's flank in crevice center.(This would make a great "Where's Waldo," but I simply don't have the time to play anymore!)
Images 4-6: This is CM10, Susan, found out basking on early in the morning on 10 November. It was a very cold day, but these molossus are showing us great indifference to cold weather. The last image of Susan shows her on the move. By 17 November, she had moved into her hibernaculum of last year.

Image 7: Good old CM11, Gus. Gus is the latest member of the Kilometer Club, having moved off IMH and traveling to the south-center slope of Suizo Mountains proper. As suggested on the file extension, this image was taken on 17 November. He has since relocated to another boulder nearby.
Image 8: Female CM15, site 13. She is also now hanging out on the southwestern slope of the Suizo Mountains. This image was also taken on 17 November.
Image 9: This is the first in situ image (since the transmitter was implanted) to be shared with you all of female CM17, "Ms. Gus." Death from above! She is in a hunt posture, ~200mm above a rodent run. Pity any rat or mouse foolish enough to run beneath THOSE snappers!
While Dale DeNardo did the surgery on Ms. Gus, one of his students, Megan by name, asked where we found her. Without hesitation, I replied "At the end of Gus's wanger." No lies were told, but I did kind of hear about crude language and students a little later.

Note the large head on this wench. It is always great fun to read Marty's write ups on the datasheet. One such entry on Ms. Gus read "Not visible. The only obvious entrance appears too narrow for her to squeeze her fat head in."

As of 25 November, Ms. Gus still had not committed to a hibernating site. She is approaching the Kilometer Club herself, now deep into Tim Canyon, which is the first slot canyon north of the front range of Suizo Mountains.

Image 10: As much as I HATE to end with plants, does anybody know what this vine is? In nearly 12 years of working the Suizos, we have never seen it before. Thanks!
That's not nearly everything, but it will have to do. Duty calls!

Best to all, roger

Thursday, November 29, 2012

The Boa Constrictor in Puerto Rico

MAYAGÜEZ, Puerto Rico— Non-native boa constrictors, which can exceed 10 feet and 75 pounds, have established a breeding population in Puerto Rico, one that appears to be spreading, according to research published in the journal Biological Invasions.

While boa constrictors and two species of pythons have established invasive populations in Florida, this research is the first to document a large constrictor species established in the United States or its territories outside of Florida. The new population appears to be spreading from its likely point of origin in the western part of the island around the city of Mayagüez. In the last year alone, more than 150 boas have been found in the wild on the island.

The established boa constrictor population likely originated with the pet trade. Genetic studies conducted by the researchers indicate that individual boas on the island are highly related and that the population probably originated with a small number of snakes. First-hand accounts from local officials suggest that newborn boas were released in Mayagüez in the early 1990s.

"Experience has shown that island ecosystems are particularly vulnerable to snake invasions, and unfortunately Puerto Rico has no natural predators that can keep the numbers of these prolific, snakes in check," said USGS Director Marcia McNutt. "Humans were responsible for introducing this scourge to the island, and are the only hope for mitigating the problem before it is too late for the native species."

Two snakes found some distance from the expanding Mayagüez population share genetic markers with that population, suggesting that people might be intentionally or unintentionally moving the snakes around the island. Such movement could potentially increase the rate of spread of this invasive snake. Because the snakes are secretive and difficult to spot, the researchers suspect the population size is large.

“We’ve learned from dealing with other invasive snakes that understanding the source of these populations and preventing spread as soon as possible is important to protect ecosystems," said USGS scientist and study co-author Bob Reed. "Once non-native snakes become established across a large area, especially in densely forested areas, they become much more difficult to find and almost impossible to eradicate."

Private ownership of boa constrictors and most other snake species is prohibited in Puerto Rico because of fears of non-native snakes becoming established.

Reynolds, R.G., A. R. Puente-Rolon, R. N. Reed, & L. J. Revell. 2012. Genetic analysis of a novel invasion of Puerto Rico by an exotic constricting snake. Biological Invasions 1-7.

Wednesday, November 28, 2012

Tropical Lizard Adapts to Florida Winter

The Puerto Rican lizard Anolis cristatellus 
pictured above has adapted to the cooler winters 
of Miami. Credit: Manuel Leal, Duke.
DURHAM, NC - One tropical lizard's tolerance to cold is stiffer than scientists had suspected.

A new study shows that the Puerto Rican lizard Anolis cristatellus has adapted to the cooler winters of Miami. The results also suggest that this lizard may be able to tolerate temperature variations caused by climate change.

"We are not saying that climate change is not a problem for lizards. It is a major problem. However, these findings indicate that the thermal physiology of tropical lizards is more easily altered than previously proposed," said Duke biologist Manuel Leal, co-author of the study, which appears in the Dec. 6 issue of The American Naturalist.

Scientists previously proposed that because lizards were cold-blooded, they wouldn't be able to tolerate or adapt to cooler temperatures.

Humans, however, introduced Puerto Rican native A. cristatellus to Miami around 1975. In Miami, the average temperature is about 10 degrees Celsius cooler in winter than in Puerto Rico. The average summer temperatures are similar.

Leal and his graduate student Alex Gunderson captured A. cristatellus from Miami's Pinecrest area and also from northeastern Puerto Rico. They brought the animals back to their North Carolina lab, slid a thermometer in each lizard's cloaca and chilled the air to a series of cooler temperatures. The scientists then watched how easy it was for the lizards to right themselves after they had been flipped on their backs.

The lizards from Miami flipped themselves over in temperatures that were 3 degrees Celsius cooler than the lizards from Puerto Rico. Animals that flip over at lower temperatures have higher tolerances for cold temperatures, which is likely advantageous when air temperatures drop, Leal said.

"It is very easy for the lizards to flip themselves over when they are not cold or not over-heating. It becomes harder for them to flip over as they get colder, down to the point at which they are unable to do so," he said.

At that point, called the critical temperature minimum, the lizards aren't dead. They've just lost control of their coordination. "It is like a human that is suffering from hypothermia and is beginning to lose his or her balance or is not capable of walking. It is basically the same problem. The body temperature is too cold for muscles to work properly," he said.

Leal explained that a difference of 3 degrees Celsius is "relatively large and when we take into account that it has occurred in approximately 35 generations, it is even more impressive." Most evolutionary change happens on the time scale of a few hundred, thousands or millions of years. Thirty-five years is a time scale that happens during a human lifetime, so we can witness this evolutionary change, he said.

The lizards' cold tolerance also "provides a glimpse of hope for some tropical species," Leal added, cautioning that at present scientists don't know how quickly tolerance to high temperatures -- another important consequence of climate change -- can evolve.

He and Gunderson are now working on the heat-tolerance experiments, along with tests to study whether other lizard species can adjust to colder temperatures.


Manuel Leal, Alex R. Gunderson. Rapid Change in the Thermal Tolerance of a Tropical Lizard. The American Naturalist, 2012; 180 (6): 815 DOI: 10.1086/668077

European Fashion & the Python Trade

Nearly a half million python skins are exported each year - almost exclusively for use in European fashion - in a massive market with a legal value of more than $1.0 billion, according to the study Trade in South-East Asian Python Skins.

Many of the skins end up as designer handbags, belts, wallets and other accessories. Italy, Germany and France are the biggest importers, while most of the skins come from Indonesia, Malaysia and Vietnam.

The trade of python products is closely controlled by CITES, a UN-linked organisation charged with protecting the endangered species and other animals whose numbers are dwindling.

"Problems of illegality persist in the trade in python skins and... this can threaten the species' survival," Alexander Kasterine of the UN-linked International Trade Centre said in the report.

With supply chains often murky, a huge part of the snakeskin trade may be illegal and unsustainable, said the study, also backed by the International Union for the Conservation of Nature and the wildlife trade monitoring network TRAFFIC.

The extent of the illegal trade is hard to quantify, with many illegal skins going undetected. But the report found the illegal trade was possibly on a par with the legal trade.

Large numbers of wild pythons are slaughtered before they can reproduce, the report found, warning that many skins supposedly from captive-bred snakes were likely poached from the wild.

A lack of oversight meant quotas were easily ignored and illegal skins were being smuggled into shipments of legal items, it found.

The European fashion industry accounts for 96% of the value of the trade. It should push for more transparency in the supply chain, the study said, calling for a "traceability system" so consumers would know if their snakeskin product is from a legitimate source.

The report also recommended "legally binding minimum skin size limits to ensure protection of immature snakes."

Legislation to Regulate Importation of Constrictors

The following story is being carried by The

One of the country’s leading conservation groups wants Congress to ban imports of reticulated pythons, green anacondas, boa constrictors, and two other constrictor snakes that pose a major threat to native wildlife. In a letter sent the U.S. House Resource Committee, American Bird Conservancy says these snakes should be added to the list of “injurious wildlife” regulated by the Lacey Act, one of America’s oldest conservation statutes designed to protect wildlife from illegal trade. The change would make importing or transporting these snakes over state lines a federal offence.

“This bill (H.R. 511 –To Prohibit the Importation of Various Injurious Species of Constrictor Snakes) is necessary to prevent the further spread of these aggressive, invasive predators,” said Darin Schroeder, Vice President for Conservation Advocacy at ABC. “It’s well-established that these snakes are highly adaptable to new environments, and that they consume a wide variety of prey, including mammal, amphibian, lizard, and threatened and endangered bird species.”

Mr. Schroeder says fast-breeding and long-lived constrictor snakes have already done tremendous ecological damage in the state of Florida, where people who originally bought the snakes as pets have released them into the wild. The Burmese python, for example, is now estimated to have a breeding population in Florida in the tens of thousands. In a recent study, scientists collected more than 300 Burmese pythons in Everglades National Park and found that birds, from the five-inch-long House Wren to the four-foot-long Great Blue Heron, accounted for 25 percent of the python’s diet in the Everglades.

Mr. Schroeder adds that wildlife in the Hawaiian Islands could face similar devastation if constrictors or other snakes were to become established there. According to a 2001 study titled, Risk to Hawaii from Snakes by Fred Kraus and Domingo Carvalho, and published in the peer-reviewed journal Pacific Science, there was a yearly average of 24 snake sightings, mostly free-roaming animals that were not recovered, reported state wide between 1990 and 2000. For ABC, that concern is heightened by facts that most of the species recovered feed largely on birds, and by the fact that 70% of all native Hawaiian birds are already either listed as threatened or endangered or of conservation concern. More than one third of all bird species listed under the U.S. Endangered Species Act are Hawaiian.

“If snakes were to reproduce and proliferate, it quickly may be too late to stop them, and as a result, every measure to keep them out of places like Hawaii needs to be taken,” said Mr. Schroder in the letter. ”ABC strongly supports H.R. 511 and urges the full committee to take up and pass this important piece of legislation and send it to the floor of the House for full consideration.”

The best-known example of the damage a non-native snake can do can be found on the island of Guam, where the brown tree snake was accidentally introduced to from its native range of New Guinea and Australia after World War II. The problems caused by those invasive snakes were not limited to the near-total devastation of the island’s bird life: they also include major disruptions of electric power transmission, telephone service, military operations, computers, and tourism. Preying on eggs and birds alike, the brown tree snake has caused the extinction of nine of the eleven native land bird species on Guam.

Orsini Viper's Reproductive Strategy

A female Orsini's viper observed at the end of August 2011. 
This snake is gestating and will give birth to two offspring a
fortnight later. Credit: Thomas Tully. This image is available
 from the CNRS phototheque,

Orsini's viper is a small insectivorous snake that is rare and extremely threatened in France. Since the early 1980s, a population of Orsini's vipers on Mont Ventoux has been the subject of an in-depth monitoring study. In total, 160 females were monitored throughout their lives, revealing that adult specimens (which can live for more than 12 years) regularly alternate between reproductive and non-reproductive years. A mathematical model confirmed that natural selection could induce alternation between reproductive years and years of growth. In this species, adult females reproduce every two years. In the non-reproductive years, snakes build up fat reserves and invest resources in body growth, which is possible throughout their lives and influences their fertility. The larger a female becomes, the more offspring she can produce. In a reproductive year, growth stops and all the acquired resources are committed to reproduction. This means that the reproductive success rate is high and that the immediate physiological impact on the mothers is low. This "strategy" differs radically from the behavior of other viviparous snake species, in which the females appear very thin after they have given birth. Their fat reserves 'melt away", which can threaten their survival. The strategy of Orsini's viper, however, allows a high quality litter to be born without such a "cost" to the parent. Monitoring females before and after reproduction to assess their condition, body growth and survival rate has shed light on the logic behind this particular reproductive behavior, which is not - as generally thought - correlated with environmental fluctuations. The findings of this research could explain many other cases of intermittent reproduction in other species of both animals and plants. They also illustrate the value of long-term individual studies on natural populations for improving knowledge of the ecological and physiological mechanisms that determine species demography.

Baron, J.-P., Le Galliard, J.-F., Ferrière, R., Tully, T. (2012), Intermittent breeding and the dynamics of resource allocation to reproduction, growth and survival. Functional Ecology. doi: 10.1111/1365-2435.12023

Migration Behavior in Giant Tortoises

While Galapagos giant tortoises move very slowly and at a leisurely pace,
they can nevertheless cover great distances. © MPI f. Ornithology
The Galapagos giant tortoise, one of the most fascinating species of the Galapagos archipelago, treks slowly and untiringly across the volcanic slopes. Scientists of the Max Planck Institute for Ornithology in Radolfzell, together with the Charles Darwin Foundation, have used GPS technology and modern 3D acceleration measurements to find out that especially the dominant male tortoise wanders up to 10 kilometers into the highlands of the island. Only the fully grown animals migrate, the young tortoises stay year round in the lowlands. The reason for this and the question of why the animals don't rest during the dry season are not known yet.

Even Charles Darwin anticipated that the giant tortoises wandered large distances. In the cool dry season, the highlands of Santa Cruz are engulfed in fog which allows the vegetation to grow despite the lack of rain. In the lowlands, however, there is no thick layer of clouds and the tortoises' vegetation is not available year round. Adults, which can weigh up to 250 kilogram, spend the dry season in the higher regions at an elevation of 400 meters above sea level. However, since the food is not as nutritious there, they trek back to the lower zones where there is succulent vegetation in abundance as soon as the rainy season begins.

In order to study the migratory pattern more closely, Stephen Blake from the Max Planck Institute for Ornithology and his colleague Washington Tapia from the Galapagos National Park secured GPS loggers with 3D acceleration monitors onto 17 adult tortoises. This allowed the scientists to determine the animals' exact position and behavior over a period of two years. In order to gather information on the entire population, the researchers noted the size, sex and location of each tortoise they met on their monthly hikes along the volcanic hillsides. They combined the GPS data with the temperature data and information about availability of vegetation.

The results show that the tortoises have a partial migration system, where not every individual migrates. Only the adult animals wander and only the larger specimens are more likely to move. In June they start their slow, tedious march which can be up to ten kilometers long into the highlands. Adult females remain in the lowlands until they lay their eggs and then they also make their way to the highlands. In contrast, the smaller tortoises stay in the lower elevated areas all year round.

Although giant tortoises are able to survive for up to one year without nourishment, which made them a popular staple for seamen, they nevertheless wander for large distances searching for food as this study shows for the first time. Why don’t they just look for a shelter? The question of why the younger animals don’t migrate hasn’t been answered by the scientists yet. “Either the energy expenditure of this strenuous hike is too high, or there is still enough food available for the smaller animals.” Stephen Blake suspects, “perhaps the younger animals can’t tolerate the wet cold climate of the higher regions.”

In other species, the largest and the most dominant individual does not migrate because it can best defend itself against its competitors. It doesn’t have to leave to survive. However, among the Galapagos tortoises, it’s usually the largest and most dominant individual which takes on this arduous journey.

Future studies on giant tortoise species of the other Galapagos Islands with varying ecological conditions will show how environment influences the migration scheme of these closely related reptiles. The scientists also want to include factors such as age, size, sex and morphology in their studies to see why the behavior changes in different lifetime stages and what the trigger of migration is.

Despite the threat of hunting, invasive species such as goats and rats, and the loss of habitat due to man, the Galapagos Tortoise still shows its original migrating behavior. This and future studies will help to maintain this behavior with the help of effective measures such as establishing corridors, preserving key habitats, keeping tortoise-friendly roads and maintaining less urban development. Based on its importance to the Galapagos Archipelago ecosystem as an herbivore and seed disperser, the annual migration of the tortoise must be preserved. Article available on-line.

A New Blunt-headed Treesnake from Ecuador

Imantodes chocoensis
Blunt-headed tree snakes range from Mexico and Argentina, and are distinct from all other New World snakes because they have an exceptionally thin body, slender neck, big eyes, and a blunt head. The arboreal snakes hunt frogs and lizards at night and their extremely gracile bodies allow them to bridge gaps between branches that most other arboreal snakes cannot. Omar Torres-Carvajal from Museo de Zoología QCAZ and colleagues (2012) have described Imantodes chocoensis, in the journal Zookeys bringing the number of species in the genus to seven. The Chocoan blunt-headed tree snake chocoensis inhabits the Chocoan forests of northwestern Ecuador. DNA data also suggest that I. chocoensis’ closest relative is a species that inhabits the Amazon on the other side of the Andes.

“One possible explanation for the disjunct distribution between the new species and its closest relative is that the uplift of the Andes fragmented an ancestral population into two, each of which evolved into a different species, one in the Chocó region and the other in the Amazon,” Omar Torres-Carvajal from Museo de Zoología QCAZ, who led the study, said in a statement.

Snakes collected as far back as 1994, and deposited in several Ecuadorian and American natural history museums were examined for the study to help determine whether this was a newly discovered species.

The head of the chocoensis is about the size of a penny, and the species slightly exceeds a meter in total length. The Chocoan forests are part of the Tumbes-Chocó-Magdalena hotspot that lies west of the Andes. The full article is available on-line.

Omar Torres-Carvajal, Mario H. Yánez-Muñoz, Diego Quirol, Eric N. Smith, & Ana Almendáriz. 2012. A new species of blunt-headed vine snake (Colubridae, Imantodes) from the Chocó region of Ecuador. ZooKeys 244: 91–110, doi: 10.3897/zookeys.244.3950

Monday, November 26, 2012

Hybrid Salamander Larvae Survive Pesticides

Three types of salamander larvae: native California tiger salamanders 
(Ambystoma californiense), barred tiger salamanders (Ambystoma tigrinum 
mavortium), and the hybrid offspring born when the two species mated. 

Photo Credit: Bruce Delgado, U.S. Bureau of Land Management.

Hybridization among ambystomid salamander species is common. Ambystoma tigrinum mavortum, the barred tiger salamander may have been introduced into California from released pets, or as fishing bait imported from the upper midwest. Whatever their origin, they have bred with the endemic California tiger salamander, Ambystoma californiense, a situation that has been well known for a number of years. In a new study Ryan et al (2012) find that in the intensively farmed Salinas Valley, California, the threatened California tiger salamanders (Ambystoma californiense) have been replaced by hybrids between California tiger salamander and introduced barred tiger salamanders (Ambystoma tigrinum mavortium).The authors conducted an enclosure experiment to examine the effects habitat modification and relative frequency of hybrid and native California tiger salamanders have on recruitment of salamanders and their prey, the Pacific chorus frogs (Pseudacris regilla). They tested whether recruitment differed among genetic classes of tiger salamanders (hybrid or native) and pond hydroperiod (seasonal or perennial). Roughly six weeks into the experiment, 70% of salamander larvae died in four out of six ponds. Native salamanders survived (n = 12) in these ponds only if they had metamorphosed prior to the die-offs. During die-offs, all larvae of native salamanders died, whereas 56% of hybrid larvae died. The authors necropsied native and hybrid salamanders, tested water quality, and queried the California Department of Pesticide Regulation database to investigate possible causes of the die-offs. Salamander die-offs, changes in the abundance of other community members (invertebrates, algae, and cyanobacteria), shifts in salamander sex ratio, and patterns of pesticide application in adjacent fields suggest that pesticide use may have contributed to die-offs. That all survivors were hybrids suggests that environmental stress may promote rapid displacement of native genotypes.

RYAN, M. E., JOHNSON, J. R., FITZPATRICK, B. M., LOWENSTINE, L. J., PICCO, A. M. and SHAFFER, H. B. (2012), Lethal Effects of Water Quality on Threatened California Salamanders but Not on Co-Occurring Hybrid Salamanders. Conservation Biology. doi: 10.1111/j.1523-1739.2012.01955.x

Saturday, November 24, 2012

Squamate Body Elongation & Climate

Gymnopthalmus underwoodi, a species not included in this study.

The evolution of elongated body shapes in squamate vertebrates has intrigued biologists for decades. Grizante et al. (2012) suggest several factors may explain how the environment influences the evolution of body elongation, and note climate needs to be incorporated in this scenario to evaluate how it contributes to morphological evolution. Climatic parameters include temperature and precipitation, two variables that likely influence environmental characteristics, including soil texture and substrate coverage, which may define the selective pressures acting during the evolution of morphology. GIS (geographic information system) techniques are now available and can now be included in evolutionary biology studies. Grizante et al used GIS in present study to test for associations between variation in body shape and climate in the tropical lizard family Gymnophthalmidae. They first investigated how the morphological traits that define body shape are correlated in these lizards and then tested for associations between a descriptor of body elongation and climate. Their analyses revealed that the evolution of body elongation in Gymnophthalmidae involved concomitant changes in different morphological traits: trunk elongation was coupled with limb shortening and a reduction in body diameter, and the gradual variation along this axis was illustrated by less-elongated morphologies exhibiting shorter trunks and longer limbs. The variation identified in Gymnophthalmidae body shape was associated with climate, with the species from more arid environments usually being more elongated. Aridity is associated with high temperatures and low precipitation, which affect additional environmental features, including the habitat structure. This feature may influence the evolution of body shape because contrasting environments likely impose distinct demands for organismal performance in several activities, such as locomotion and thermoregulation. The authors establishes a connection between morphology and a broader natural component, climate, and introduces new questions about the spatial distribution of morphological variation among squamates.

Grizante MB, Brandt R, Kohlsdorf T (2012) Evolution of Body Elongation in Gymnophthalmid Lizards: Relationships with Climate. PLoS ONE 7(11): e49772. doi:10.1371/journal.pone.0049772

New Report of a Rare Bothrops

Murici Lancehead, Photo Frank Stemitz

Bothrops muriciensis was described more than a decade ago by Ferrarezi & Freire (2001) from Brazil's Atlantic Forest on the basis of three specimens. Freitas et al.(2012) report on six more specimens collected in the Murici region of Alagoas, Brazil. They increase the number of localities the snake has been found at, note that it is terrestrial, and found about 400 m in elevation. And, they suggest the IUCN should consider the species Critically Endangered. Its survival is probably dependent on the Murici Ecological Station, while the forest around it is being removed. The new specimens records include juveniles and adults that were close to streams. The full article can be found on-line.

Freitas, M. A. et al. 2012. Notes on the conservation status, geographic distribution and ecology of Bothrops muriciensis Ferrarezzi & Freire, 2001 (Serpentes, Viperidae).  NORTH-WESTERN JOURNAL OF ZOOLOGY 8 (2): 338-343.

Friday, November 23, 2012

Herps of the Tucker Valley Bioblitz

The first BioBlitz in Trinidad and Tobago was held in Tucker Valley in Chaguaramas on November 17 & 18. The idea behind a BioBlitz is to identify as many species as possible in a chosen area within 24 hours, provided science with some information and raise awareness of biodiversity within the general public. Tucker Valley includes a variety of forest types and has an adjacent marine environment that includes a coral reef and sea grass beds. Tucker Valley was chosen as the site for the country's first-ever BioBlitz because of its wide range of habitats, including four different types of forest, freshwater rivers and streams; seagrass beds at the southern end in Williams Bay; and coral reef at the northern end in Macqueripe Bay.
The event was well attended by the general public and media.
Mike Rutherford at work.
Probably the second most likely frog species to be found
 the tungara frog, Engystomops pustulosus.

The least likely snake to be found, Lachesis muta.
Forty-one species of herps (frogs, turtles, lizards, and snakes) had been previously reported from the valley, so how many could be found in 24 hours? My unofficial count was 25 species  (10 frogs, 1 turtle, 1 crocodilian, 8 lizards, and 5 snakes) or about 61% of the known fauna. Perhaps the biggest surprise was a 2 meter bushmaster found DOR by the birding group. Lachesis muta had not been previously reported from the valley.

Saturday, November 10, 2012

Steroids & Temperature Influence Sex Determination in Gekko japonicus

Sex determination is a developmental process altering undifferentiated gonads into testes or ovaries. Vertebrates have two types of sex determination: genotypic sex determination (GSD), in which offspring sex is determined at the time of fertilization by genetic factors and environmental sex determination (ESD), where environmental factors act after fertilization at a critical time in embryonic development to determine offspring sex. 

Temperature dependent sex determination (TSD) is one form of ESD. TSD is widespread in reptiles including all crocodilians, tuataras, many turtles and some lizards. The discovery that in TSD species temperature is not the only factor influencing sex determination suggests that other factors, especially maternal influences via yolk steroid hormone deposition, can influence the end result of the sexual differentiation process, although the influence (direction and/or magnitude) of a given steroid hormone may be species-specific. For example, eggs with elevated levels of corticosterone are more likely to produce daughters in the Jacky dragon, Amphibolurus muricatus, and sons in the three-lined skink, Bassiana duperreyi.

Ding et al. (2012) incubated eggs of the Japanese gecko Gekko japonicus at three temperatures, and measured yolk testosterone (T) and 17β-estradiol (E2) levels at three time points in embryonic development (oviposition, 1/3 of incubation, and 2/3 of incubation), to examine whether maternal influence on offspring sex via yolk steroid hormone deposition is significant in the species. Eggs incubated at 24 °C and 32 °C produced mostly females, and eggs incubated at 28 °C almost a 50:50 sex ratio of hatchlings. Female-producing eggs were larger than male-producing eggs. Clutches in which eggs were incubated at the same temperature produced mostly same-sex siblings. Yolk T level at laying was negatively related to eggs mass, and yolk E2/T ratio was positively related to egg mass. Their data in G. japonicus show that maternal influence on offspring sex via yolk steroid hormone deposition is significant; incubation temperature affects the dynamics of developmental changes in yolk steroid hormones; influences of yolk steroid hormones on offspring sex are secondary relative to incubation temperature effects; and offspring sex correlates with an interaction between incubation temperature and yolk steroid hormones.

Ding G-H, Yang J,  Wang J, Ji X. 2012. Offspring sex in a TSD gecko correlates with an interaction between incubation temperature and yolk steroid hormones. Naturwissenschaften 1-8,