Dipsas variegata - the 44th species of snake reported from Trinidad

A comparison of Dipsas trinitatis (A 

and c) and Dipsas variegata (B and D).

Thirty six species of the snail-eating snakes in the genus Dipsas are currently recognized. One species, Dipsas trinitatis Parker is known only from Trinidad. The original description of Dipsas trinitatis (Parker, 1926) was based upon a single male specimen from the Trinity Hills and a second specimen without locality data. Parker recognized its close relationship to the mainland South American Dipsas variegata and distinguished the two species using the presence/absence of a preocular, the number of upper labials, and differences in color pattern, characters now known to be variable in both taxa. In an overall review of dipsadine snakes Peters (1960) relegated D. trinitatis to a subspecies of D. variegata based on color differences from the mainland populations. Emsley (1977), Murphy (1997) and Boos (2001) followed this recommendation and discussed this snake as D. v. trinitatis.

Until now, all references to Dipsas on Trinidad have referred to Dipsas trinitatis Parker. Murphy and Rutherford (2014) have now report the presence of Dipsas variegata on Trinidad. Its presence is based upon a single female specimen, identified as Dipsas trinitatis, was found in the collection of The National Museum and Art Gallery of Trinidad & Tobago and now stored in The University of the West Indies Zoology Museum (UWIZM). Its large size (796 mm total length, 607 mm SVL), bulky head, tall upper labials, an eye diameter that is about equal to the eye-mouth distance readily distinguish it from its congener, Dipsas trinitatis. The specimen agrees well with all 16 diagnostic characters for the species listed by Harvey and Embert (2008).

Collection data accompanying the specimen reports it locality as Macqueripe Bay on the north coast of the Chaguaramas Peninsula and adjacent to Tucker Valley.

The smaller head in D. trinitatis has been noted previously, but placed side-by-side the size difference is dramatic and it appears Dipsas variegata is macrocephalic, while D. trinitatis is microcephalic. Microcephalism evolved in several sea snakes (Hydrophis, family Elapidae, Hydrophiinae) that specialize in hunting snake eels in crevices. The smaller head allows the snake to probe holes and crevices to extract the fish. Since Dipsas feeds on snails and extracts them from their shells it seems probable that the difference in head size is adaptive for a specific type of prey, or a specific foraging strategy (possibly removing snail bodies from shells of different sizes or extracting snails from crevices). Feeding behavior and diet in these snakes is poorly known it is unclear as to how head size relates to diet or foraging.

Dipsas variegata is the 44^th species of snake reported from Trinidad and the second species of Dipsas from the island. In addition there is a third species of snake specialized for feeding on gastropods from Trinidad – Sibon nebulata.

Citation

Murphy JC, Rutherford, MG. 2014. The snail-eating snake Dipsas variegata (Duméril, Bibron and Duméril) on Trinidad, and its relationship to the microcephalic Dipsas trinitatis Parker (Squamata, Dipsadidae). Herpetology Notes, 7: 757-760. 

Hyla goughi Boulenger resurrected for the Trinidad & Tobago Dendropsophus minutus population

Dendropsophus goughi Boulenger

In the Neotropics, nominal taxa such as the toad Rhinella margaritifera (Bufonidae), the thin-toed frog Leptodactylus fuscus (Leptodactylidae), and the tree frog Scinax ruber (Hylidae) are prominent examples of anuran species once considered to occur across nearly the entire tropical lowlands of South America. Evidence has accumulated that many such putatively widespread species could in fact be complexes of cryptic taxa. However, given limited genetic sampling and the difficulty in reviewing material from all countries hosting populations, their relationships and systematics remain in many cases as unclear as they were decades ago.

Dendropsophus minutus (Peters, 1872) is a small hylid frog, 21–28 mm snout-vent length, distributed in Cis-Andean South America, including the Andean slopes, the Amazon Basin, the Guiana Shield, down to the Atlantic Forests of southeastern Brazil, with an elevational record from near sea level up to 2,000 m. Variation in coloration, osteology, advertisement calls and larval morphology, along with molecular data from limited parts of the species' distribution suggest the nominal D. minutus might represent a species complex. However, the sheer size of its supposed geographical range along with nomenclatural and taxonomic complexity (six junior synonyms) and unresolved relationships in the D. minutus species group have so far made these frogs inaccessible to revision.

Gehara et al. (2014) use D. minutus to understand to what degree a small-sized, tropical anuran has the potential to be continentally widespread with limited genetic structure within its range, as expected for a single species. In addition to conservation concerns, this question has important implications for South American biogeography in general and amphibian systematics and evolution in particular. Evidence is accumulating that body size in amphibians has a positive correlation with range size, but contrary to this trend many Holarctic amphibians occur with little genetic substructure across the vast ranges they colonized after the last glaciation, despite sometimes moderate to small body sizes. Whether such patterns also exist across vast ranges in tropical regions, with their distinct historical climatic dynamics, is an open question. Deciphering possible cryptic diversity within the nominal D. minutus would also help inform conservation assessments which typically use species' geographic distributions as criteria for conservation status.

The phylogenetic tree based on the 16S gene containing all Dendropsophus for which sequences were available recovered the monophyly of the D. minutus species group. Within the group, the clade containing samples representing lineages 19–43 received a maximal posterior probability (1.0) and is defined here as the D. minutus complex, given that lineage 25 contains samples from the type locality of D. minutus.

Most of the mitochondrial lineages containing more than one sample received strong nodal support. The lineages splitting off from basal nodes of the tree (lineages 1–18) are distributed in the Guiana Shield, and in the Andean region of Peru, Ecuador and Colombia, with an eastern extralimital clade assembling disjunct localities in Mato Grosso and Pará.

The remaining lineages are in general more widely distributed in central and eastern South America Lineages are largely allopatric but several cases of sympatry were observed. The uncorrected pairwise distances between lineages for the 16S gene ranged from 0.7 to 13%, while within-lineage p-distances ranged from 0.0 to 1.8%.

Most of the lineages (45%) were found in only one or two localities. Fifty per cent of the lineages were only found in areas smaller than 10 km², and more than 70% have known ranges smaller than 10,000 km². Eight out of the 43 lineages have a distribution larger than 100,000 km2. Largest range sizes were found in northeastern Brazil (Caatinga domain; 997,262 km², lineage 36), eastern Bolivia and western Brazil (Cerrado, Chaco and Dry Forest domains; 293,321 km², lineage 33) and the Guiana Shield (269,741 km², lineage 2).

Among the D. minutus species group members external to the D. minutus complex, lineages 1–6 are Guianan, while 7–18 are primarily distributed along the Andean foothills, and all show well-pronounced molecular differentiation and divergence. Among lineages 1–6, there is moderate genetic differentiation. Considering mitochondrial reciprocal monophyly and GMYC results as criteria, and being taxonomically conservative, one available name, Hyla goughi Boulenger, 1911 (type locality: Trinidad), should likely be removed from the synonymy of D. minutus and allocated to populations comprised by all or some of lineages 1–6. As a conservative estimate, the authors hypothesize that lineages 7–18 comprise seven distinct species, i.e., five named taxa and two undescribed species (lineages 9+10 and 11+12).

Data presented herein provide conclusive evidence for a strong genetic subdivision of the nominal species Dendropsophus minutus as currently understood. Current taxonomy conservatively assumes a putatively widespread species encompassing a vast area of South America (from approximately latitude 11.0°N to 35.0°S), distributed across several biomes. Our results, however, reveal high genetic diversity within D. minutus that would suggest the existence of numerous distinct species, leading to an important increase in number of species. If this hypothesis is confirmed through further studies, the existence of an increased number of species with decreased range sizes would have important consequences for the definition of centers of endemism and for assessing conservation status.

Citation

Gehara M, Crawford AJ, Orrico VGD, Rodríguez A, Lötters S, et al. (2014) High Levels of Diversity Uncovered in a Widespread Nominal Taxon: Continental Phylogeography of the Neotropical Tree Frog Dendropsophus minutus. PLoS ONE 9(9): e103958. doi:10.1371/

2014 Trinidad Bioblitz is fast approaching, herpetology participants please read the following

The third annual T&T Bioblitz, taking place this year in and around Nariva Swamp, is coming up on the 18^th-19^th October. 

On the 18th and 19th October wildlife experts and enthusiasts will be taking part in the third annual T&T Bioblitz. This year it is being held in Nariva Swamp and the plan is to try and record as many different species of plants, animals and other organisms as possible within 24 hours. The event is being organized by Mike Rutherford, the curator of the UWI Zoology Museum, in partnership with the T&T Field Naturalists’ Club, Forestry Division and many other groups. The experts start surveying on Saturday 18th at noon and then work through the night before inviting the public along on the Sunday morning to go on guided tours, see science in action and learn more about the local wildlife. Come along and join in!

The Bioblitz in Nariva provides an opportunity to confirm the presence of some interesting animals.

At the top of the list is the matamata turtle. There has been considerable speculation about an established population on Trinidad. Finding one in Nariva would support that idea, but they are very difficult to see and totally aquatic – so the freshwater group may want to keep an eye out for them also. It’s more likely one will turn up in a seine while looking for fish, than someone will actually see one in the water. Other turtles are also of interest and I would encourage people who find them to hang on to them long enough to get positive IDs and photos.

Similarly, it is likely the herp group or the freshwater group will find the totally aquatic frog Pipa pipa. I have not seen these recently, but saw them in abundance in the 1980’s in the southwest portion of the island. Museum and literature records support their presence in Nariva. Collecting one for photos and tissue would be valuable.

Another high priority species is the semi-aquatic lizard, Kentropyx striata, they are present in the Nariva area, I saw one 2012. But they are buggers to catch. When approached they quickly dive into the water, but you will see them sitting in bushes and on logs. Again, collecting one for photos and tissue would be very valuable. Note they look very much like a Cnemidophorus, but Cnemidophorus do not go into the water.

Other high priority species for photos, specimens, and tissues: Polychrus marmoratus (one specimen from Bush-Bush looks quite distinct from those of the Northern Range), Tupinambis teguixin, Hydrops triangularis, Erythrolamprus (Liophis) cobellus, Clelia clelia, Drymarchon corais, Spilotes sulphureus and of course any of the worm snakes. And, let’s not forget anoles, skinks and frogs, interesting specimen may turn up.

It is unlikely we will find crocodiles, river turtles or aquatic caecilians but you never know! Seeing an anaconda is likely so keep your camera’s ready.

Oh, yes, don’t forget road kills. Please pick them up, they are great for voucher specimens and DNA even if they are super flat.

You can find more on the T&T Bioblitz Facebook page

A new snake from Trinidad, and its significance to the big picture

There is no doubt that there are many, many more species of amphibians and reptiles than previously thought. Peter Uetz, maintains the Reptile Database website, and he recently announced that in 2014, the number of known reptile species passed the 10,000 mark – and the year has not yet ended. In an email Uetz wrote the number of reptile species is, “10,038 species (including 79 described this year), up from 9,952 in April”. While some of these species are obviously different, many of them are cryptic, and it takes some detailed study of morphology or DNA to sort them out.

Trinidad is a relatively small island – 4800 square kilometers that has had its herpetofauna relatively well studied. The first list of herps was published in 1858, and the work by Mole and Urich at the turn of the 20th century examined the fauna extensively. William Beebe spent the last years of his life at Simla in the Arima Valley and published a fauna list as well as a paper on the ecology of the valley. Garth Underwood and Michael Emsley also studied and wrote about the island’s herpetofauna. Julian Kenny and Hans Boos were also actively working on the Trinidad herpetofauna for decades. And I made five- or six trips to the islands and examined museum specimens in the 1980-90’s for the 1997 book. During those trips, I frequently stayed at Simla and worked extensively in the Arima Valley. In 2010, I decided to take a second look at the fauna and since that date have made eight trips to investigate the herpetofauna of both Trinidad and Tobago. Additionally, I have been working with colleagues to compare museum material from the islands to those from the mainland – the results are startling.

It has become quite obvious to me that the diversity of reptiles on that 4800 sq km, well studied island (as well as the island of Tobago) is much greater than what I (or anybody else) thought it was in 1990.

Within the last few years, we have described Plica caribeana and Leptophis haileyi. The Plica is a Caribbean Coastal Range species, and the Leptophis appears to be a Tobago endemic. There are more species forthcoming – for the most part it is a matter of time and money to get the work done. But, preliminarily we have identified at least ten more species of squamate reptiles currently unrecognized from the islands or masquerading under the name of a widespread species.

In a forthcoming paper in the Journal of South American Herpetology, Teddy Angarita-Sierra describes a new, cryptic species of coffee snake, in the genus Ninia – from Trinidad. It would normally not surprise me, that a small, leaf litter dwelling snake would go un-noticed in the tropics. But, this snake is surprising because the of the type locality – Simla. A location that has to be the most closely examined piece of real estate on the island – in terms of its fauna.

Ninia atrata left, Nina franciscoi sp. n. right. T. Angarita-Sierra

Angarita-Sierra describes Ninia franciscoi, from a single specimen collected at Simla 6 March 1988 by William B. Montgomery and David Resnick. This specimen looks very much like the widespread Ninia atrata (also found at Simla) except for the number of upper labials contacting the primary temporal and most importantly, an unusually shaped hemipensis (see right).

Nina franciscoi sp n.,top, Nina atrata bottom.

After reviewing this paper – I went back and looked at about forty specimens of Ninia atrata from Trinidad and Tobago as well as all of my photographs, looking to see if any of the others had the primary temporal in contact with three upper labials. Some of these specimens were collected at Simla – none showed this trait.

So, what is the significance of this? Below is a power point slide I used in a recent presentation comparing the number of reptile species per 1000 km² in Trinidad & Tobago to Venezuela. The islands are much better studied than the mainland. Trinidad & Tobago have 4.2x more known species of reptiles per 1000 km² than does Venezuela (this is using the numbers from the 1997 book). In other words mainland South America (specifically Venezuela) most likely has a vast number of undescribed reptiles.

As for those undescribed Trinidad and Tobago squamates - one of them is a third species of Ninia. Below is typical Ninia atrata. 

Gymnophthalmus underwoodi on Tobago

The shiny lizard, Gymnophthalmus underwoodi, is one of those reptiles that is widespread and probably common,  but not particularly easy to find. It is small, lives in burrows or under objects, and is active only when the sun is shining - when it can significantly raise its body temperature. Its distribution ranges from Venezuela, the Guyanas, and Brazil northward into the Lesser Antilles. It has been reported as far north as Antigua. Humans may, at least in part, be responsible of its island distribution.The shiny lizard is frequently associated with lawns and gardens and as people transport their favorite plants from palace to place these tiny lizards may move with them. Additionally it is a unisexual species which provides the advantage of not needing a mate. In fact, G. underwoodi is one of four species in a complex of cryptic species (the others are: G. cryptus, G. leucomystax, and G. specious). Kiziran & Cole (1999) found G. cryptus is the ancestor of G. underwoodi.

Hardy (1982) commented on the lack of specimens of Gymnopthalmus underwoodi from Tobago, Cole et al did find find specimens from Tobago, nor did Murphy (1997). Yet some publications and websites have included Tobago in the distribution- the IUCN red list is an excellent example. It presence on Tobago would seem reasonable given its presence in Trinidad and Venezuela and the Antilles. However, a HerpNet search did not show any specimens from Tobago.

On 6 June 2013 Rick Lehtinen collected a single specimen of G. underwoodi in from of the Vegetable King in Castara, Tobago. Thus confirming its presence on the island. The specimen is deposited in the UWIMZ. Since that date the species has become quite abundant on the northeastern end of the island.

Literature

Cole, CJ, et al. Gymnophthalmus (Reptilia Teiidae) in the neotropics: genetics origin and systematics. American Museum Novitates (2994): 1-29

Hardy, J. D. 1982. Biogeography of Tobago, West Indies, with special reference to amphibians and reptiles, a review. Bulletin of the Maryland Herpetological Society 18(2):37–142.

Kizirian DA. Cole CJ. 1999. Origin of the Unisexual Lizard Gymnophthalmus underwoodi (Gymnophthalmidae) Inferred from Mitochondrial DNA Nucleotide Sequences. Molecular Phylogenetics and Evolution 11:394–400.

Murphy, J. C. 1997. Amphibans and reptiles of Trinidad ad Tobago. Krieger Publishing, Malabar, FL.

Is Chironius scurrulus part of the Trinidad herpetofauna?

In 1993 Dixon et al. reported on a specimen of Chironius scurrulus from Trinidad. The specimen, UMMZ 43965 is a juvenile that was collected by E. B. Williamson, an insect collector at the turn of the 20^th century (winter 1912). Wagler’s Sipo as it is sometimes called inhabits Brazil, SE Colombia, N Bolivia, Ecuador, Venezuela, E Peru, Trinidad, Guyana, Surinam, French Guiana according to the Reptile Database website, and probably has a type locality of Rio Japura, Brazil (based on comments in Kornacker 1999). Boos (2001) also reported this species as part of the Trinidad herpetofauna, following the previous authors.

The UMMZ specimen of Chironius scurrulus said to be from Trinidad

Recently I visited the UMMZ and examined the specimen of Chironius scurrulus, it is undoubtedly that species, but there is evidence to suggest it did not come from Trinidad.  Also collected by Williamson that winter on Trinidad were some Rhinella marina, Hypsiboas crepitans, Mannophryne trinitatis, and several specimens of the stream toad, Atelopus hoogmoedi. The last species is of course unknown from Trinidad – but it is known from Guyana, the other country visited by Williamson during the winter of 1912. Given the low probability of picking up the only known specimen of Chironius scurrulus and the only known specimens of Atelopus hoogmoedi from Trinidad on one trip, it seems likely that the specimens were instead collected in Guyana and at some point mislabeled as to their origins.

I would like to thank Greg Schneider at the UMMZ for searching the archives for information on these specimens, and to César Luis Barrio-Amorós, J. Roger Downie, and Joanna Smith for their perspectives into these records.

Citations

Boos, H.E.A. 2001. The snakes of Trinidad and Tobago. Texas A&M University Press, 270 pp.

Dixon, J. R., Wiest Jr, J. A., & Cei, J. M. 1993. Revision of the neotropical snake genus Chironius Fitzinger Serpentes, Colubridae. Torino: Museo regionale di scienze naturali.

Photos needed for the next Trinidad & Tobago Field Guide

We are making progress on the Trinidad and Tobago Field Guide and the goal to to have it ready for copy editing by the end of 2014. The extended dry season of 2014 has made it difficult to find animals and we still are looking for photos of  species we don't have represented. While it is improbable we will find live specimens of species known from a single specimen or just a few specimens we are looking for the best photography we can find. We are also looking for the best photography of Trinidad and Tobago specimens - that is we would rather have photos of specimens from the islands than from the mainland or other islands if at all possible.

So the following is a list of species we still need, or we need better photos than the ones we have. If you have photos that you are willing to let us use - send me (JCM) an email at: serpentresearch@gmail.com

Leptodactylus nesiotus, Pristimantis turpinorum, Mesoclemmys gibba, Anolis extremus, Anolis trinitatis, Anolis wattsi, Kentropyx striata, Drymarchon corais, Leptophis stimsoni,, Tantilla melanocephala Erythrolamprus cobella, Erythrolamprus ocellatus, Hydrops triangularis, Thamnodynastes ramonriveroi, Micrurus circinalis, Micrurus lemniscatus diutius, Lachesis muta. 

If you have great photos of other species we are interested. 

Bush Maco Trinidad & Tobago and a new Wildlife Policy for T&T

The following announcement  comes from the Bush Maco website. A new effort to document, track and share your Trinidad &  Tobago nature sightings. Bush Maco is just starting out, so they need your support and feedback. Many people can document much more than just one or two can. This is the power of citizen science. Your observations will be used to track the natural cycles of animal and plant species.

Fantastic news for wildlife in Trinidad and Tobago....the Wildlife Policy has been approved by Cabinet! Well done to the hardworking team who wrote it and to all the members of public who contributed to improving this policy through the public consultations!The National Wildlife Policy was formally approved by Cabinet in December, 2013. A Draft Wildlife Policy was developed for Trinidad and Tobago by a Cabinet-appointed Technical Committee and was made available to the general public for comment and public consultations were held during the period January to March, 2013 throughout Trinidad and in Tobago. Additionally, The Ministry of the Environment and Water Resources facilitated special meetings for major stakeholders to elicit views and recommendations on the Draft Policy.

These comments were then reviewed and used to revise the Draft by the Technical Advisory Committee. Once final adjustments were made, the Draft Policy was sent to Cabinet for consideration and on December 19, 2013 Cabinet adopted the National Wildlife Policy for Trinidad and Tobago.

The Ministry of the Environment and Water Resources, the Forest Division and the Tobago House of Assembly express gratitude to all those who participated and contributed to the process of finalising the Policy and as such, enhancing the policy framework for the sustainable management of wildlife resources of the country.  Development of an appropriate legislation and administrative framework for the implementation of the Wildlife Policy is currently underway.

Summary of the National Wildlife Policy

The Wildlife Policy provides guidance on the sustainable management of undomesticated animals and plants, whether introduced, resident or migratory, their parts or derivatives, and their habitats. It addresses issues related to endangerment and provides guidance on the management of threatened species. It also addresses key policy issues on the management of game species, wildlife habitat and the engagement of civil society in the management of wildlife.

Bush Maco is also on Facebook