The frog Leptodactylus nesiotus is no longer endemic to Trinidad

Leptodactylus nesiotus from Trinidad. Photo by Renoir Auguste.

As of 2014, the island of Trinidad was known to have four species of endemic frogs: Trinidad stream frog Mannophryne trinitatis, Urich's litter frog Pristimantis urichi, Golden tree frog Phytotriades auratus and Trinidad thin-toed frog Leptodactylus nesiotus. 

In 2015, there were now three endemic species after the discovery of the Golden tree frog (Phytotriades auratus) in Venezuela (Rivas and de Freitas 2015). Now, at the end of 2018, the number of endemic frog species is down to two after Leptodactylus nesiotus were discovered in the Guianas (Guyana, Suriname and French Guiana), South America.

The Trinidad thin-toed frog (Leptodactylus nesiotus) is a member of the Leptodactylus melanotus group. They are known from swampy areas in south west Trinidad and also from the Nariva Swamp. Jairam and Fouquet (2018) reported on specimens occurring along coastal savannas and swamps on mainland South America, along the Guianas. Given the very wide distribution and continuity of habitat, the authors suggest that specimens of L. nesiotus may have been mistaken for L. validus or other species of the L. melanotus group. They also suggest that specimens are also likely to occur in Venezuela and may even occur in Colombia and Brazil. 

Little is known about the biology of the species from Trinidad and prior to its discovery in South America, it was given the IUCN Red List Status of Vulnerable. With an extension of greater than 1000 km, perhaps the status of Vulnerable now needs to be reassessed to Least Concern. 

It is unsurprising that L. nesiotus is not an island endemic to Trinidad, especially given its main population in south western Trinidad is less than 20 km from Venezuela. Also, in Trinidad, the species has been observed to live alongside L. validus. Perhaps further investigations of other endemics may reveal a much wider distribution, which further highlights the biogeographical link to the Trinidad and South America fauna.

Literature Cited

Rivas, G. and de Freitas,M. 2015. Discovery of the critically endangered Golden tree frog Phytotriades auratus (Boulenger, 1917), in eastern Venezuela, with comments on its distribution, conservation, and biogeography. Herpetological Review 46: 153-157.

Jairam, R. and Fouquet, A. 2018. First records of Leptodactylus nesiotus (Anura: Leptodactylidae) for Guyana, Suriname and French Guiana. Herpetology Notes 11: 997-999.