The bird snakes (Pseustes & Spilotes) rearranged

The genus Pseustes Fitzinger, 1843 is composed of three known species, Pseustes poecilonotus, P. shropshirei and P. sulphureus. Pseuestes sulphureus may be the largest sized colubrid snake in the New World, although Drymarchon corias has a similar or possible greater size. But, both species may exceed 3 meters in total length. Pseustes has been classified as belonging to numerous other genera, over the years, including: Ahaetulla, Chironius, Coluber, Dipsas, Herpetodryas, Natrix, Phrynonax, Spilotes, Synchalinus, Thamnobius and Tropidodipsas. Pyron et al. (2013) found support that Pseustes sulphureus is the sister taxon to Spilotes pullatus, both members of the Colubrinae. However, the estimated phylogenetic position of this species was only based on a single 12S gene fragment as part of a large study. The study, used genes from 4161 species of squamates.  

In a forthcoming paper, Jaden et al. used multiple individuals of Pseustes across Central and South America and they analyzed the genus to infer the phylogenetic position of Pseustes within the Colubrinae, assess the relationship between Spilotes and Pseustes, and determine whether species of the genus Pseustes form a monophyletic group, infer phylogenetic relationships within Pseustes, and species-level diversity to resolve historical taxonomic debates. 

The authors examined four species from multiple specimens across their distribution and analysed one nuclear and two mitochondrial genes to determine the phylogenetic placement of the genus and infer relationships among Pseustes lineages. They found strong support for the paraphyly of Pseustes with respect to the monotypic genus Spilotes, both of which are nested within a clade of at least 23 other New World Colubrinae genera. 

The results produced a new view of the genera Psuestes and Spillotes. The authors resurrected the taxon P. polylepis for populations of P. poecilonotus from South America and moved P. sulphureus to the genus Spilotes which renders both genera monophyletic. Psuestes sulphureus is the type species of the genus Pseustes, and moving it to the genus Spilotes requires the allocation of the senior synonym Phrynonax be considered for the remaining Pseustes taxa.

Citation
Jadin RC., Burbrink FT, Rivas GA, Vitt LJ, Barrio‐Amorós CL, and; Guralnick RP. (2013). Finding arboreal snakes in an evolutionary tree: phylogenetic placement and systematic revision of the Neotropical birdsnakes. Journal of Zoological Systematics and Evolutionary Research. DOI: 10.1111/jzs.12055

New Version of the Herpetology of Trinidad & Tobago Web Site Now On-line

Today the next generation website for the Herpetofauna of T&T was put on-line. I am hoping the new web site and this blog will act to generate interest in the Field Guide. Please look it over and let me know if you encounter problems - with content or web access. Any account lacking accompanying photos means that we need photos for that species. JCM

The Trinidad Plica is now Plica caribeana

The lowland tropics were once though filled with widespread species, while moderate and higher elevations were thought to contain species with more restricted distributions. That idea is turning out to be partially incorrect. Widespread species now appear to be the exception, instead of the rule. A new study describes four species once considered to be the collared treerunner, a lizard known to the scientific community as Plica plica. The study was published in the open access journal ZooKeys.

The Trinidad Plica, is now Plica caribeana

The collared treerunner was originally described in 1758 and has been the subject of many biological, ecological, and behavioral studies in recent years. A new ZooKeys paper by John C. Murphy, Field Museum (Chicago) and Michael J. Jowers, Estación Biológica de Doñana (Sevilla, Spain) describe four new species formerly thought to be one.

“The collard treerunner was considered a single species ranging from Trinidad and Tobago and northern Venezuela southward into the Amazon Basin, south of the Amazon River.” Murphy said.” The Treerunners ancestor diverged about 25-30 million years ago, and throughout this time the South American continent has undergone dramatic remodeling, including the rise of the Andes, rising and falling sea levels, and changing climates that isolated populations for long periods of time, allowing them to become new species. Treerunners live on vertical surfaces, such as tree trunks, rock walls, and even buildings and they eat a variety of insects.

The new paper focuses on populations of this lizard in northern South America, but in an overall survey the authors examined specimens from across the Amazon basin and suspect there may be at least another five to seven undescribed species in what is currently considered the collared treerunner. The treerunners from Trinidad and northern Venezuela were 4.5% genetically different from those in southern Venezuela, and more than 5% different from those in Brazil. For comparison purposes humans and chimpanzees are less than 2% genetically different.

While some species may form by genetic divergence without showing any morphological differences from their ancestor, other often show subtle or obvious morphological differences that may be quite easy to detect. The latter is the case with the collard treerunners.

Some had as few as 92 scales around the body while others had 202 scales around the body. Some adult males have yellow heads while other have red heads, some have distinctive patterns of spots while others have transverse bands.

Unraveling cryptic species is important for a more complete understanding of biodiversity, evolution, and for long term conservation efforts.

The take home message here is that there are many more species of squamate reptiles (lizards and snakes) in the world than previously thought, and it is likely many species have and will disappeared before science is even aware of them. Cutting forests and draining swamps undoubtedly causes extinctions of the species depending upon those habitats. While none of the treerunners described in this paper are likely to be threatened with extinction this discovery and many other similar recent discoveries suggest our knowledge of biodiversity is lacking.

Citation
Murphy JC, Jowers MJ (2013) Treerunners, cryptic lizards of the Plica plica group (Squamata, Sauria, Tropiduridae) of northern South America. ZooKeys 355: 49–77. doi:10.3897/zookeys.355.5868

A new snake species from Tobago

Until now two snake species of the genus Leptophis (parrot snakes) have been known to  inhabit Trinidad and Tobago. One, L. stimsoni, is endemic to Trinidad’s Northern Range and known from relatively few specimens. The second is the diurnal, arboreal, brightly colored parrot snake Leptophis coeruleodorsus.

The genus Leptophis was first reported in Trinidad and Tobago by Reinhardt & Lütken (1862), and while it appeared on lists, no natural history information was reported until Mole (1924) described its diet. Oliver described the Trinidad & Tobago populations of Leptophis as  L. coeruleodorsus in 1942, and in 1948 re-classified it as a subspecies of L. ahaetulla. Oliver viewed Leptophis ahaetulla as a species with 147–183 ventrals, 135–185 subcaudals, 18–28 maxillary teeth, and a distribution extending from about 22º N latitude to 35ºS latitude (a straight line north-south distance of about 7500 km). Oliver’s 13 subspecies were based primarily on coloration, as well as ventral and subcaudal counts and he viewed much of the morphological variation as clinal.

The second known species of Leptophis on Trinidad is Leptophis stimsoni Harding, a Northern Range endemic and a member of the L. riveti Group. The first specimen was collected by Sanderson in 1937 from the summit of Mt. Aripo (Cerro del Aripo), and was considered to be L. riveti  by Emsley (1977). No other specimens were known until 1987 when two specimens, one from the Arima Valley and another from Cumaca Cave were collected. Harding (1995) described L. stimsoni as distinct from L. riveti.

Murphy et al. (2013) compared 11 specimens of the L. ahaetulla Group using DNA sequences from two mitochondrial genes (cytochrome b and 16S, 1,383 bp total) from island and mainland populations, reported on the variation in the morphology of 54 museum specimens of Leptophis a. coeruleodorsus; restrict the type locality of L. coeruleodorsus to Mt. St. Benedict; and they describe a new species of Leptophis from the island of Tobago that can be distinguished from L. coeruleodorsus on the basis of snout shape, upper labial architecture, elongated prefrontal scales, and ventral scale counts.

Leptophis haileyi is the only Tobago Leptophis to have a subacuminate snout in profile; the rostral is barely visible from above; the primary temporal is in contact with three or four upper labials, including the last; prefrontal scale is long, it has a high ventral count (173) and it is a male, with a tail/SVL ratio that falls with in the range of female L. coeruelodorsus.   All L. coeruleodorsus examined have two upper labials contacting primary temporal with last upper labial excluded from contact with primary temporal.

(a) Leptophis coeruleodorsus (b) L. haileyi

The new species is currently known from a single specimen from the northeast portion of Tobago in the vicinity of Roxborough and is named in honor of Adrian Hailey for his work on the Trinidad and Tobago herpetofauna. This description raises the number of endemic Tobago amphibians and reptiles to 11 taxa.

Citation
MURPHY, J. C., CHARLES, S. P., LEHTINEN, R. M., & KOELLER, K. L. (2013). A molecular and morphological characterization of Oliver’s parrot snake, Leptophis coeruleodorsus (Squamata: Serpentes: Colubridae) with the description of a new species from Tobago. Zootaxa, 3718(6), 561-574.

Trinidad Sphaerodactylus, I am looking for a banded one!

The dwarf day geckos of the genus Sphaerodactylus are primarily lizards of the Caribbean. The Reptile Database lists 101 currently recognized. Relatively few species are known from mainland Central and South America. Harris (1982 Occas. Pap Mus Zool. Univ Michigam  no. 704) reported five South American  spercies (S. heliconiae, S. lineolatus, S. molei, S. scapularis, and S. notatus). Species described since 1982 have been either Central American or West Indian (mostly Cuba and Hispanolia) and the only species present on Trinidad and Tobago has been thought to be S. molei, a gecko also in coastal Venezuela and Guyana. However, two musuem specimens with the locality data of "Trinidad" have been found that are clearly not S. molei.  I am writing this with the idea that readers will find this lizard. It is distinctive in that the body is transversely banded; and molei has longitudinal stripes. It is possible the locality data is wrong, it is possible the lizards were accidentally introduced from another island, but the specimens are not in great shape and getting scale count data and  other scale characteristics from them is at best problematic. So, should you find a tiny banded lizard, a Sphaerodactylus on Trinidad, send me an email or please take it to the Zoology Museum at UWI so we can identify it. Photos of a juvenile S. molei and one of the banded species are shown below.

The Second Trinidad Bioblitz

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

A 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, 

Generic changes likely for some Trinidad Chironius

Convergent evolution sometimes covers the tracks of genetic lineages, so species can appear to be very similar but have different ancestors. Such appears to be the case with some of the snakes currently in the genus Chironius.  In Trinidad & Tobago, there are three species of Chironius, Machete savane, C. chironius chironius, the long-tailed machete, C. septentrionalis, and the smooth machete C. surrulus (this species is known from only a few specimens on Trinidad).  The sixteen species in the genus tend to have triangular shaped bodies in cross-section, large eyes, 14 or few scale rows at mid body,  they to to actively forage during the day and feed on frogs and lizards. They range from Central America to southern South America and inhabit some of the Lesser Antilles.

In a new study of squamate relationships, Pyron et al. (2013) found Chironius to be polyphyletic, with C, carinatus and C. quadricarinatus forming a clade and with nine other species that were included in the study, forming a second clade. The second clade contains C. septentrionalis and  C. scurrulus.
 Chironius carinatus is the type species of the genus, thus it and quadricarinatus (and whatever other species not included in the study are related to it) will retain the name Chironius. The second, however, will need a new name, and the oldest name available for the clade will likely be Macrops (= large eyes), a genus established by Wagler in 1830 for Linnaeus' species Coluber saturnius, which is now known as Chironius fuscus.

This result demonstrates how little we actually know about the Neotropical Herpetofauna, the prevalence of species that look similar but are genetically distinct, and the problems caused by the polytypic species concept. Sorting out the details of this promises to be challenging because several of the currently recognized species of Chironius have subspecies, including C. carinatus.

Citation
Pyron, RA, Burbrink FT, Wiens JJ. 2013. A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes. BMC Evolutionary Biology 13:93 doi:10.1186/1471-2148-13-93

A night out on Tobago

Walking in the oldest protected forest in the Western Hemisphere at night you expect to see frogs, lizards, and snakes as well as interesting arthropods and the occasional mammal, on Tobago this might be an agouti or an armadillo. What you don't expect are feral dogs. Eight of us were surveying the herpetofauna on Thursday night only to find we had been joined by two dogs. They were friendly enough, and accompanied us along the trail  from the beginning to the end. It was a interesting walk with several of the endemic Trinidad and Tobago frogs calling as well as an Oxybelis aeneus sleeping on a branch above the trail and an Imantodes cenchoa stalking a Pristimantis urichi. We came off the trail at a point that required a hike back to the car. Here we encountered a third dog, it was lying curled in the grass, a necrotic ear, swollen jaw, and visible ribs and its behavior suggested it was dying. Lacking a way to kill it quickly we returned to the cars.

One of our canine companions. 

While we were all sympathetic to the dogs they do not belong there, they cause damage to wildlife populations, as well as being a potential human health problem.

The winding road between Charllottville and Speyside on Tobago can be treacherous for both humans and animals. There are a large number of blind curves and when combined with reckless driving (a very common problem on the island) the results can be lethal. While returning from field work a car with its flashers on had pulled over to the side of the road and the people were standing in the road at a relatively wide spot. We slowed down, and then stopped when we saw the 2.2 m boa in the road. Some of us directed traffic around the snake while others took photographs; all the while being warned by an intoxicated on-looker that the snake would bite us if we got too close. The gravid female was quite tolerant of the flashes and people moving around her.

The 2.2 m boa constrictor.

This was the fifth Boa constrictor we had seen during the week. All of the others were road kill, except one that had been dispatched with a machete. After taking a few photos, we dragged the snake off the road.

Boa constrictors are the largest predators on the island with the exception of humans and could be used to help control feral dogs and cats if people would only leave them alone. An education program for residents that emphasizes not killing snakes and not releasing or dumping household pets, as well as keeping them locked up at night, could go along way toward protecting snakes and the forest as well as solving the feral pet problem.

Aquatic post-escape behavior of the green iguana on Tobago

Green iguanas are well known for diving into streams from arboreal basking sites, but their behavior under water after the escape has to my knowledge not been reported, other than they swim away. While hiking in the Hillsborough River on Tobago on the morning of  7 June a one meter (total length) green iguana (Iguana iguana) dove into the river as we approached. After looking around the area for about 10 minutes I returned to the area where the iguana had been seen. Walking the shoreline the green and black bands of an iguana tail were visible underwater and upon closer inspection the lizard was lying on the bottom of the stream (about 40 cm deep) slightly under the bank and some floating roots. The lizard was less than 15 meters from its original point of entry into the stream. The lizard did not surface or move during  10 minutes  of observation. Several photographs were taken, and then I waded into the water and approached the lizard, for more photographs. During this time the iguana flicked its head several times in response to a crayfish that was touching its nose, but it did not respond to my presence even when I was less than half a meter from it, and bent directly over the lizard for more photographs. When two students approached on land, a leaf had drifted over the lizard's head and so they could also view and photography the lizard I reached into the water within a few centimeters of the head and removed the leaf. Again the lizard did not respond to my presence. Only when one of the students slipped in the stream did the lizard move, and it slowly swam away. Like many cryptically colored species, the green iguana relies on its camouflage to avoid predation underwater, but not in arboreal or terrestrial situations.

The submerged green iguana relying on its coloration to avoid detection. JCM

Close-up of the submerged lizard's crown. JCM

Frogs, ecotourism, and litter

After a day of monsoonal rains the hylid fog Trachycephalus typhonius move to a breeding pond, males start to call, and soon the noise becomes overpowering. Just off the Northside Road in Tobago one of the most spectacular auditory displays in the amphibian world, and in all of nature, could be seen and heard. On June 3rd, we found a chorus than consisted of hundreds of individuals. Males pushed and chased other males away when they came too close. Females were picking males to amplex with, probably based on the qualities of the male's call, but the position of the male within the chorus. An important choice that will influence the success of her genes in the next generation. Satellite males were frequently standing by pairs in amplexus, and males were frequently challenging each other. Other herps nearby included the rattle-voice treefrog, Hypsiboas crepitans and the tungara frog, Eupemphix pustulosus, as well as the slug-eating snake, Sibon nebulata, and the cat-eyed snake, Leptodiera annulata.

Male Trchycephalus chasing way a competitor, note blue fabric at bottom left. JCM

The Trachycephalus chorus is one of those spectacular events that everyone appreciates when they see it. However, this particular chorus was marred by the fact that the breeding pond was full of bottles, cans, plastic containers and styrofoam trays. Trinidad and Tobago could develop an ecotourism industry around the herpetofauana as they have for birds - chorusing Trachycephalus would be a high interest event that would draw people from all over the world. People who would be staying in hotels, eating in restaurants, and paying tour guides. But, the trash problem needs to be solved first.

Calling male Trachycephalus amid debri. JCM

Whistling frogs synonymized

Leptodactylus validus and tadpoles on Tobago. JCM

The very abundant whistling frog, Leptodactylus validus, has been long considered a Caribbean species, with populations in the Lesser Antilles, Trinidad and Tobago. In 2006, Yanke et al. used molecular data to demonstrate that the South American whistling frog, L. pallidorostris was conspecific with the Caribbean whistling frog. Leptodactylus pallidorostris inhabits Venezuela, Guyana, Suriname, and French Guiana.

In a more recent paper, Heyer and Heyer (2012) compare calls, larval morphology and adult morphology that agree with the molecular results, Leptodactylus validus occurs in in the Lesser Antilles (as far north as Bequia), Trinidad and Tobago, as well as northern South America.

As more molecular and morphological  information on the Trinidad and Tobago herpetofauna becomes available a more detailed and refined biogeographical portrait of the islands will emerge.


Literature Cited
Heyer W.R. and M/ M. Heyer (2012) Systematics, distribution, and bibliography of the frog Leptodactylus validus Garman, 1888 (Amphibia: Leptodactylidae). Proceedings of the Biological Society of Washington, 125:276-294.

Yanek, K., W. R. Heyer, and R. O. de Sa´. 2006. Genetic resolution of the enigmatic Lesser Antillean distribution of the frog Leptodactylus validus (Anura, Leptodactylidae). South American Journal of Herpetology 1:192–201.

Treeboa Phylogeny

A Tobago specimen. JCM

Treeboas of the genus Corallus (subfamily Boinae), had a Gondwanan origin. As noted in the previous post there are eight species  recognized based on morphology and some have been confirmed with molecular data: C. annulatus, C. batesii, C. caninus, C. cookii, C. cropanii, C. grenadensis, C. hortulanus, and C. ruschenbergerii. Four of these species are endemic to South America, including the rare and very poorly known C. cropanii, which is known from four specimens (three existing) and whose taxonomic placement has been of great interest. Two species are distributed in both Central and South America (C. annulatus and C. ruschenbergerii), and two species are endemic to the Lesser Antilles (C. cookii and C. grenadensis). Phylogenetic relationships have been explored using morphology and molecular phylogeographic analyses have been conducted on 115 individuals. However, a time-calibrated phylogeny for all species has not been available.

In a forthcoming paper, Colston et al. (2013) use DNA sequence data from two mitochondrial and three nuclear genes from all species of Corallus to infer their phylogenetic relationships and reconstruct their biogeographic history. The authors find Corallus diversified within mainland South America, and disperse over-water to the Lesser Antilles and Central America, and they used the traditionally recognized Panamanian land bridge. Divergence time estimates reject the South American Caribbean-Track as a general biogeographic model for Corallus and suggest Oligocene and Miocene played a role diversification. These events include marine incursions and the uplift of the Andes. The results also suggest that recognition of the island endemic species, C. grenadensis and C. cookii, is questionable as they are nested within the widely distributed species, C. hortulanus.

The research suggests that Ruschenberg's treeboa C. ruschenbergerii dispersed from South America to Central America during the Pleistocene via the traditionally recognized Panamanian land bridge, although the results also allow for the possibility that C. ruschenbergerii may have arrived in Central America prior to the closure of the Panamanian Isthmus in the middle Miocene.

Citation

Colston, T.J., et al. (2013) Molecular systematics and historical biogeography of tree boas (Corallus spp.). Mol. Phylogenet. Evol., http://dx.doi.org/10.1016/j.ympev.2012.11.027