Sunday, September 29, 2013

Evidence for a Triassic origin for Lepidosauria


Top: Vellberg jaw. Bottom: restoration image.
 Illustration Credit: Marc Jones.
Two new fossil jaws discovered in Vellberg, Germany provide the first direct evidence that the ancestors of lizards, snakes and tuatara (known collectively as lepidosaurs) were alive during the Middle Triassic period -- around 240 million years ago.

The new fossil finds predate all other lepidosaur records by 12 million years. The findings are published in BMC Evolutionary Biology.

The international team of scientists who dated the fossil jaws have provided evidence that lepidosaurs first appeared after the end-Permian mass extinction event, a period when fauna began to recover and thrive in the more humid climate.

Lead author Dr Marc Jones, who conducted the research at UCL, explained: "The Middle Triassic represents a time when the world has recovered from the Permian mass extinction but is not yet dominated by dinosaurs. This is also when familiar groups, such as frogs and lizards, may have first appeared."
The small teeth and lightly built jaws suggest that the extinct animal preyed on small insects. The new fossils are most closely related to the tuatara, a lizard-like reptile.

Tuatara can be found on 35 islands lying off the coast of New Zealand and were recently reintroduced to the mainland. However, they are the sole survivors of a group that was once as globally widespread as lizards are today. Tuatara feed on beetles, spiders, crickets and small lizards, also enjoying the occasional sea bird.
Today, there are over 9,000 species of lizards, snakes and tuatara. Knowing when the common ancestor of this grouping first appeared is crucial for understanding the ecological context in which it first evolved as well as its subsequent diversification.

To establish the age of the fossil remains, biologists use a dating technique known as a "molecular clock." This method compares the amount of genetic divergence between living animals, caused by changes in their DNA sequences that have accumulated since they split from a common ancestor. These mutations occur fairly regularly, ticking along at a clock-like rate. However, for the clock to convert genetic differences into geological time, it has to be calibrated using one or more fossils of known relationship and time.

Molecular clocks have been used by biologists to answer questions as important as when the first modern humans emerged, and when humans and chimpanzees shared a common ancestor. The new fossil jaws can improve molecular dating estimates of when reptiles began to diversify into snakes, lizard and tuatara, and when the first modern lizards inhabited the earth. Previous estimates have varied over a range of 64 million years and the team are keen to help narrow this down.

"Some previous estimates based on molecular data suggested that lizards first evolved 290 million years ago," said second author Cajsa Lisa Anderson, University of Gothenburg. "To a palaeontologist this seems way too old and our revised molecular analysis agrees with the fossils."

Revised molecular dating in light of this new fossil find now suggests lizards began to diversify into most of the modern groups we recognize today, such as geckos and skinks, less than 150 million years ago in the Cretaceous period, following continental fragmentation.

The specimens were collected and initially identified by Professor Rainer Schoch from the Staatliches Museum für Naturkunde in Stuttgart, where the specimens are now registered.

Scientists anticipate that the Vellberg site will yield yet more fossil discoveries in the future, broadening our knowledge of the vertebrate fossil record.

Co-Author Professor Susan Evans, from the UCL Department of Cell and Developmental Biology, said: "The fossil record of small animals such as lizards and frogs is very patchy. Hopefully, this new fossil site in Germany will eventually give us a broader understanding of what was going on at this time."

Citation

Jones MEA, Aderson L, Hipsley CA, Müller J, Evans SE,  Schoch RR. 2013. Integration of molecules and new fossils supports a Triassic origin for Lepidosauria (lizards, snakes, and tuatara). BMC Evolutionary Biology, 13 (1): 208 DOI: 10.1186/1471-2148-13-208

The Second Trinidad Buioblitz

The second annual Trinidad Bioblitz has come and gone.  This year it was held in the very biodiverese Arima Valley, with the base camp at the Asa Wright Nature Center. The preliminary tally of species was - Vertebrates 139, Invertebrates 247, Fungus 30, Diatoms 7, Plants 317 for a grand total of 740 species!

Teams include: Mammals, Freshwater (Fish, Aquatic Insects, Crustaceans), Amphibia and Reptilia, Birds, Molluscs, Spiders and other Arachnids, Butterflies and Moths, Social Insects, Myriapods millipedes/ centipedes) and Worms, Flowering Plants, Ferns, Lichens, Orchids and Fungi.

The Arima Valley has been the crown jewel for Trinidad's biodiversity for centuries, the site has been the geographical location for much of the scientific research that has occurred on Trinidad including classic studies of bats, guppies, and the herpetofauna as well as many other higher taxa. However, active quarrying operations threaten the habitat, and the activity of bush meat hunters threaten larger animal populations. But, perhaps the most significant sign that the valley is under development - the installation of sidewalks along the road.

But, the Bioblitz results suggest the flora and fauna are doing well at least for the moment. Teams of experts and volunteers  searched the valley for 24 hours attempting to identify as many species as possible. But, it can be more than just a list, because the opportunity of natural history observations is under every log and in every fruiting tree.

 Informational displays by various groups including the Trinidad and Tobago Field Naturalist Club, UWI Zoology Museum, Asa Wright Nature Center and Wildlife Division were present to  inform the public. So what about the herpetofauana. Here are some photos of what was found.

An Arima Valley Bothrops cf asper. was sitting in the vegetation close to a
 chorus of Hypsiboans crepitans.
Top: a juvenile Chironius carinatus, bottom Chironius (Macrops)
septentrionalis. Both juveniles and very difficult to distinguish
from each other, but look at the relative size of the eyes

Hypisboans crepitans hiding in the vegetation during the day.

Epictia tenella was found climbing a tree trunk, it was about a meter
off the ground and was probably headed for a rotten liana filled with
termites.

A juvenile Oxyrhopus petolarius

Anolis planiceps sleeping on a leaf.

A male Gonatodoes vittatus perhaps the most common seen
reptile during the Bioblitz
The leaf-nesting frog, Phyllomedusa trinitatus



Friday, September 13, 2013

Suzio Report, Summer Fun

Howdy Herpers,                                                         9/12/13

Well friends, it has been too long since Typing Boy here has addressed you. I trust that the lack of reports lately has not caused too much angst in your lives?

So much has happened since Marty found that little tortoise in the black widow spider web that I hardly know where to begin. I do know that this had better be good, and my face now retains the red marks of a severe bitch-slapping from my own hand. There are 2600 reasons to shine now. Wake up and address these people, Roger! And make it count. Dammit!

As some of you know, the Herp Accountant here has been keeping close tabs on every turtle, snake, and lizard that he encounters. In some cases, the counts go back to 1989. But the common lizard numbers did not begin in earnest until the year 2000. It is that 12 plus year time period, along with the common lizards, that are going to be discussed next.

While every herp found is enshrined in my hallowed herp journal, there are really only six species of lizard that I consider indicators of how good or bad a herp year is. Experience has taught me that these wiggly little suckers, to varying degrees, are the herps that clearly demonstrate how good or bad a year can be.  Without further adieu, these six species are Zebra-tailed Lizards, Side-blotched Lizards, Whiptails, Desert Spiny Lizards, Regal Horned Lizards, and, of course, Gila Monsters. There is another number that plays as a wild card in my judgment of a herp year. That is the total number of lizards encountered.

The same system is used on snakes and turtles. We are not going to talk all that much on these except for one thing: 2013 is heading toward the worst herp year that I’ve ever had for snakes. At the end of August, 160 snakes were logged. My worst snake year ever was 221, and that was in 2002. Unless things pick up mightily, the lamenting in the year-end report for the Tucson Herpetological Society Journal is going to be impressive in both content and duration. (And if you want to see that report, you will have to become a member of the THS. Cough up your 20 bucks, pikers!).

Now that we have discussed what is bad in 2013, can we move on to the good? Great! Let’s mow these lizards down in order. For the Zebra-tailed Lizards, my best year of the century was 1,519. That was in 2008. With two months of possible encounters remaining, (they shut down by early November), the number for 2013 is 1,398. Already, 2013 is the second best year of the century. Will we beat 2008? Time will tell! With the Side-blotched Lizards, unless hordes of them suddenly rain down upon us, we will wind up with only slightly above average numbers. No big deal. Their best use is conversion to Lyresnake mass. Hopefully, that’s where they all went this year. We’re done with the likes of them. With the Whiptails, (several species), we have already broken the record set last year. That number was 453. We are now at 575! In 2008, I encountered 137 Desert Spiny Lizards. The count for these chunky fat heads is currently 108, which is 35 above average over the time period under discussion. Again in 2008, 20 Regal Horned Lizards were found which I crowed mightily about at the time. In 2013, the number now stands at 23, with more incoming expected. This is a record-breaker for one of the lizards that I love most! Last year, a record number of 32 Gila Monsters were encountered. At this point in 2013, we are at 25. We are already at the third best year of the century with these numbers, and again, more incoming is expected. Last, but not least, the wild card. Again, in 2008, the all species of lizard count was 2,978. This year, we are at 3,043! If we did not see one more stinking lizard for the remainder of the year, we are still walking in tall cotton.

We will stop with this type of herpetological bean-counter talk here, and move on to the hard-wired snakes under watch in paradise. Before my emailed leg-hump of late, we had 14 different rattlesnakes under watch, and were facing the prospect of cutting some of those out of the game. Thanks to what I am now calling the 2600 club, our N is now 17. And we expect to bump that to 20 by the end of this month. Yes sirs and madams, 20 transmitters will soon be merrily blipping across a swath of remote Sonoran Desert Thornscrub 2 kilometers long by 1 kilometer wide. When we fire up those receivers, we will not know whether to defecate, or go blind. This is called “fun.”  The thrill of mowing down 20 rattlesnakes whilst hoofing through a sticker-infested wonderland is mother’s milk to the few, the proud, the geeks! Thanks guys! And come on out to play with us sometime………

As much as Typing Boy would like to show you each and every snake that we have out there now, that is not possible. Truth be told, some of the newer snakes have yet to reveal themselves for good, in situ images. A case in point is our newest snake, CA134, a young male atrox. We released him on the evening of 31 August. I did not track him for the first time until 7 September. His signal was coming from the center of a flat, heart-shaped slab of gneiss. When I looked into the soil entrance, I saw two large adults looking back out at me. CA134 was behind these two­ no doubt stuck until they decide to leave. Right off the bat, he leads us to a mini aggregation. Sensational!  

Until now, I have made no mention of a little sweetheart of a female molossus that is under watch. She is CM18, as yet un-named. She is just shy of 2 feet long, and her rattle count is basal, 4 segments, and a button. Marty found her hanging out with our pregnant molossus CM17. Mother, daughter? Time will tell, I just hope that the DNA gets processed in my lifetime so that we will know for sure. The first image in this report is of her. We released her on 10 August, and with the first tracking on 14 August, she has scored a meal. Bully for her!

Speaking of scoring meals, Mr. Feldner was blessed to observe, and subsequently photograph, our female tiger CT13 track down and consume a pocket mouse. See image number 2. Following her feast, she moved from the flats to the top of Iron Mine Hill. A fattened female will draw in males quicker than flies on feces. Like a jack rabbit on a hot date, our male tiger, CT11, made a major move of over 300 meters to join her. And on the evening of 7 September, lucky Marty and John Slone found the pair in full coitus. See image 3. While we were blessed to see five pairings last year, this is the first mating event with tigers that we have ever witnessed. We’re moving on up!

I’ve tossed a hodge-podge of images into this report. They’re all labeled, so that you will know who is who and when. Look for a full screen view of a cluster of three barrel cacti. Where’s Waldo? The next image reveals him. Look for two images of a tortoise. The first shows the surreal backdrop of a Sonoran Desert, and the second pulls the rear of the tortoise into view. Look carefully at the rear vertebral scute. That is what is left of a license plate that was affixed to his shell in 2005. It took that rascal eight years to finally wear off. Nice job, Josh! Check out the nice string of rattles on CT14. This snake in particular is still in the game for another year, thanks to the 2600 club. He was on the bubble prior to your generosity. He is probably less grateful than we are about the prospect, but there is no allowance for poop socks on our turf. 

The second to the last image is a teaser for you. You won’t have to look too hard to see that there is more than one snake in that image. By June, despite assurances from Dr. DeNardo that CM10, “Susan,” had six neonates in her ovaries, we had determined that Susan was not pregnant. The night that this photo was taken, I was still under the notion that she was not pregnant. I was correct! It was not until 10 days after this image was taken that the two neonates were discovered.



























Everybody ought to carry a camera. They come in handy sometimes! Our next report will center on matters of fecundity in paradise. For now:

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. It is a place where every meal is a banquet, every sunrise is an event, and every sunset brings the promise of good things lying ahead. 


Thursday, September 12, 2013

Rhacophorid frog phylogeny on Borneo

Kurixalus appendiculatus
Rhacophoridae is a major clade of Afro-Asian tree frogs, that has radiated into many different niches. Rhacophorids contribute significantly to the high species richness and reproductive diversity of Sundaland vertebrates. Nonetheless, rhacophorid evolution, especially on Borneo, has not been studied within a phylogenetic context. In a new study Hertwig et al. examine the phylogenetic relationships of 38 (of 41 known) Bornean  rhacophorid frogs, in combination with data from previous phylogenetic studies. In the final super matrix of 91 species, they analyse sequence data from two mitochondrial and three nuclear genes. The results show the genus Rhacophorus as a paraphyletic  assemblage. Consequently they transfer Rhacophorus appendiculatus and R. kajau to two other genera and propose the new phylogeny-based combinations- Kurixalus appendiculatus and Feihyla kajau, respectively. Surprisingly they also found Theloderma moloch, a northeast Indian species, is an independent lineage of frogs within the  rhacphorid clade, separate from the other species of Theloderma (asperum, corticale, and rhododiscus) in the study. They also use their phylogenetic hypotheses to reconstruct the evolution of reproductive modes in rhacophorid tree frogs. Direct development to the exclusion of a free larval stage evolved twice independently, once in an ancestor of the Pseudophilautus + Raorchestes clade in India and Sri Lanka, and once within Philautus in Southeast Asia. The deposition of egg clutches covered by a layer of jelly in Feihyla is also present in F. kajau and thus confirms its generic reassignment. The remarkably high diversity of rhacophorid tree frogs on Borneo is the outcome of a complex pattern of repeated vicariance and dispersal events caused by past changes in the climatic and geological history of the Sunda shelf. The authors also identified geographic clades of closely related endemic species within Rhacophorus and Philautus, which result from local island radiations on Borneo.

Citation
Hertwig ST,  Schweizer M, Das I, Haas A. 2013. Diversification in a biodiversity hotspot – The evolution of Southeast Asian rhacophorid tree frogs on Borneo (Amphibia: Anura: Rhacophoridae). Molecular Phylogenetics and Evolution 68: 567–581.

Tuesday, September 3, 2013

The record-sized alligator


The major news outlets are carrying the story of Dustin Brockman of Vicksburg, Mississippi who, with his brother and friend, killed a 727-pound record breaking alligator that was 13 feet, 4.5 inches long. The previous weight record was 697.5 pounds, according to a Mississippi Department of Wildlife, Fisheries, program coordinator.

Brockman is quoted as saying, “We chased him for about two hours, ...Then we got a shot on him.” The alligator was shot with a crossbow before they could shoot it with a shotgun. It took four hours to get the gator into the boat, it was too heavy for the three men to handle so they just waited in the middle of the river for the sun to rise. At 6:30 (a.m.) Brockman called three or four more guys to help load the alligator into the boat.

Just an hour prior to the Brockman catch, another hunting party led by Beth Trammell of Madison, Mississippi hooked a 13-foot, 5.5-inch alligator near Redwood. The Trammell party's alligator broke the previous weight record with their 723.5-pound catch until Brockman broke it 60 minutes later.

According to the media the current length record  has yet to be broken, is 13 feet, 6.5 inches. That alligator was captured on the Pascagoula River in 2008, according to the Mississippi Wildlife, Fisheries and Parks department.

Now, these are certain large animals. But neither qualifies as the record size alligator. In fact, neither iseven close to being the record sized alligator. Edward Avery Mc lLHenny's 1935 book, The Alligator's Life History is a natural history classic. Mc lLHenny's  describes the alligator's voice, hibernation habits, den construction, feeding habits, reproduction, growth, predation and other aspects of alligator life history in great detail.  All of which has been subsequently verified by 20th century crocodilian biologists. Mc lLHenny's  lived on Avery Island, Louisiana and became a prominent conservationist and wildlife advocate. 

On page 59 of his book, Mc lLHenny's  writes,


"There is plenty of evidence in the written record of long past observers that alligators in Louisiana attain an extreme length of, at least eighteen or twenty feet. To my certain knowledge, there has been taken in the vicinity of Avery island, three alligators exceeding eighteen feet in length. One of these was an alligator known to we boys as "Monsurat," killed by Mr. Robert Mooney at Avery Island in 1879, which was measured by my father. This alligator was eighteen feet, three inches in length. The next large one that I remember seeing measured, was killed by Robert Dell, our plantation overseer, in October, 1882, at the junction of the road across the marsh joining Avery Island with the mainland, at the Avery Island end. Dell was coming in over the road and saw this alligator crossing the road. He had a pistol with him, and shot the alligator from his horse, killing it. On his describing its size to my father and uncles, a four-mule team and wagon was sent to bring it to our house. This alligator measured eighteen feet, five and one-half inches."

He continues with a description of an alligator he killed and measured on January 2, 1890  in a small bayou that connected lake Cock with Vermilion Bay (LA). The animal measured 19 feet 2 inches. This is the record generally accepted by herpetologists for the largest Alligator mississippiensis.

Citation
MclLHenny, E. A. 1935. The Alligator's Life History.The Christopher Publishing House, Boston. 117 pp.