A New Matamata Species. Now there are two

The bizarre Matamata from South America was always thought of as one species, Chelus fimbriata. It did though seem odd that the one species is present in both the Amazon and in the separate river drainages in northern South America. In the 1990s some morphological differences were found in specimens from these distinct geographical regions. Now it has been established using both mitochondrial and nuclear DNA that the two populations separated about 12.7 million years ago, the time the Orinoco Basin in the north was formed. Matamatas living in the Orinoco and Rio Negro Basins and in the Essequibo drainage are morphologically and genetically distinct from those in the Amazon Basin and the Mahury drainage. The authors of the new paper have, therefore, split the old species into two: Chelus orinocensis from the former with C. fimbriata retained for the latter.

I have only seen one Matamata, other than those in zoos, and that was in the semi-wild state. During our trip to Guyana in 2006 we stayed for a couple of days at Rock View, a lodge in Annai on the Rupununi River, a tributary of the Essequibo. There in a large concrete tank lived a large Matamata which had been collected locally. The woman who looked after it climbed into the tank and lifted it out so that we could see and photograph it. This magnificent chelonian, which feeds  by sucking its prey into its mouth by a rapid expansion of the pharynx, was obviously of the newly described species, Chelus orinocensis.

Showing the location of Annai in Guyana. The Essequibo River reached the Atlantic to the north

  

Vargas-Ramírez M, Caballero S, Morales-Betancourt MA, Lasso CA, Amaya L, Martínez JG, Viana MS, Vogt RC, Farias IP, Hrbek T, Campbell PD, Fritz U. 2020. Genomic analyses reveal two species of the matamata (Testudines: Chelidae: Chelus spp.) and clarify their phylogeography, Molecular Phylogenetics and Evolution148, doi.org/10.1016/j.ympev.2020.106823.

Sánchez-Villagra MR, Pritchard PCH, Paolillo A, Linares OJ. 1995. Geographic Variation in the Matamata Turtle, Chelus fimbriatus, with Observations on its Shell Morphology and Morphometry. Chelonian Conservation and Biology 1, 294-300.

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Peter Dunn

I started to write this article a couple of days ago. That evening I found from Tim Melling a tribute on Flickr to Peter Dunn, the co-leader of that Naturetrek trip to Guyana, who had died earlier that day. Peter, a retired policeman from Scarborough, was well-known to birders in Yorkshire was well as to Naturetrek clients both as a leader and as compiler of those essential checklists. Our abiding memory is of Peter walking along a baking hot track wearing the Wellington Boots he had, after experience leading trips in Belize, wisely brought with him. With Flowers of Sulphur applied liberally to his thick socks he avoided the dreaded chiggers; the rest of the party did not.

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