Sciency Thoughts: Four new species of Treerunner from northern South America.

Thursday, 6 November 2014

Four new species of Treerunner from northern South America.

Treerunners of the genus Plica are Iguanid Lizards found in South America east of the Andes. They are medium sized, conspicuous Lizards that are active in the daytime, living in small colonies on rock outcrops or trees, and therefore are well represented in museum collections, as they tend to attract the attention of collectors. There are four species currently recognized, though two of these are considered to be both widespread and morphologically variable, making it likely that there are a number of cryptic species (species that cannot easily be differentiated from similar species by simple visual examination, but which are nevertheless reproductively isolated) within the group.

In a paper published in the journal ZooKeys on 25 November 2013, John Murphy of the Field Museum of Natural History in Chicago and Michael Jowers of the Departamento de Etología y Conservación de laBiodiversidad at the Estación Biológica de Doñana describe four new species of Treerunner, from populations previously described as Plica plica.

The first new species described is named Plica caribeana, in reference to its distribution, on the Caribbean coast of Venezuela and the islands of Trinidad and Tobago. Plicac aribeana has a lower number of dorsal scale rows than Plica plica, 92-125 as opposed to 126-140, and was confirmed to be a separate species by genetic analysis. It is mottled green and brown in colour, with distinctive black markings, females tend to be slightly larger than the males. The species lives in colonies of 6-15 individuals in forests or forest edges, and is frequently observed on trees, rock-faces, buildings and even in caves. The species is insectivorous, feeding on Ants, Beetles, Spiders, Cicadas and other Arthropods, and itself appears to be a favoured prey item of the Tropical Flat Snake Siphlophis compressus. Females lay clutches of two eggs.

Plica caribeana, from the Arima Valley of Trinidad. Murphy & Jowers (2014).

The second new species is named Plica kathleenae, in honour of the herpetologist Kathleen Kelly of the Division of Amphibians and Reptiles at the Field Museum of Natural History. The species is described from a single male specimen collected by Emmet Reid Blake near the headwaters of the Itabu Creek in the Sierra Acarai Mountains of Guyana, close to the border with Brazil, during the Sewell Avery British Guiana Expedition of 1938. The specimen has 158 dorsal scale rows at mid body (considerably more than Plica plica) and is a dark brown colour with dark and light spots; though this is its colouration preserved in alcohol, and probably differes from the colouration of the living animal.

The head of Plica kathleenae in dorsal view. Murphy & Jowers (2014).

The third new species described is named Plica medemi, in honour of Colombian herpetologist Fredrico Medem, who collected the single known specimen of this species at Cerro de las Pinturas in Colombia in 1957. This species is also described from a single male specimen, with 145 dorsal scale rows at mid body. The specimen is green with dark spots and an orange head; since it is preserved in alcohol it was most likely more strikingly coloured in life.

The head of Plica medemi in dorsal view. Murphy & Jowers (2014).

The final new species described is named Plica rayi, in honour of Ray Pawley the former Curator of Reptiles at Brookfield Zoo, for his lifelong work with Reptiles and Amphibians. This species has 182-202 dorsal scale rows at mid body (considerably more than any other member of the group. The Lizards are a dark brown colour with black and white markings, the males develop red or orange markings on their faces in the breeding season. The species is known from colonies at two sites on the Orinoco River, at Puerto Ayacucho in Venezuela and at Puerto Carreno in Colombia, and has been seen at other sites along the river. The species is found in granitic rainforests (i.e. rainforests standing on granite-derived soils), and favours rocky areas. The breeding season is in May.