Tuesday, August 19, 2014

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

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