Monday, November 25, 2013

New species of Neotropical Treerunners in the genus Plica

Treerunners are diurnal, medium sized lizards that sit in the open on vertical surfaces, and are often in small colonies that include adults of both sexes and juveniles. The sounds they make scurrying on the bark of trees or rock outcrops draws attention to their presence and thus, they are common in museum collections.

The tropidurid lizard genus Plica (treerunners) currently contains four species restricted to South America east of the Andes. Two of these are relatively widespread (Plica plica and P. umbra). The other two species are associated with Pantepuis. Plica lumaria is known only from southern Venezuela’s Guaiquinima Tepui, and P. pansticta  from the Yutaj√©–Corocoro massif of Amazonas, Venezuela.

 Etheridge (1970) restricted the type locality for Lacerta plica Linnaeus to the vicinity of Paramaribo, Suriname, designating NRM.112 as the lectotype. Hoogmoed (1973) further restricted the locality to the confluence of the Cottica River and Perica Creek, Suriname. However, the collared treerunner, Plica plica, is known from the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname, and Venezuela, as well as the islands of Trinidad and Tobago, and including the Bocas Island group Additionally, two specimens collected in the 19th century in the British Museum with the locality data “Grenada.”

Of the four species of Plica currently recognized only P. umbra lacks tufts of spines on the neck; and it has 43–69 scales around mid-body. Plica lumaria is black, the superciliaries are directed laterally, it lacks clusters of spines on the fold below the auditory meatus, and it has 141–156 rows of scales around mid-body and 27–33 lamellae under the fourth toe. Plica pansticta has 143–164 scales around mid-body and 31–39 lamellae under the fourth toe. However, P. plica (sensu Etheridge 1970) has 92–202 scales around mid-body; 21–35 lamellae on the fourth finger and 28–45 lamellae on the fourth toe. The polytypic P. plica has been the subject of ecological, morphological, and phylogenetic studies.

Murphy and Jowers (2013) took another look at Plica plica and uncovered multiple species that have been overlooked. While they focused their work on noethern South America, they did examine specimens from across the distyribution of Plica plica and estimate it contains at least 10 species, four of which are described in the new paper published in ZooKeys.

Caption. (a) Plica caribena sp. n. named for its Caribbean coastal distribution. Photo JCM; (b) Plica rayi named in honor of Ray Pawley for his life long work and interest in herpetology. Photo Zelimir Cernelic; (c) Plica plica. Photo Cesar Barrio Amoros; (d) Plica medemi named after Colombian herpetologist and collector of the specimen Fredico Medem. Photo JCM (e) Plica kathleenae named in honor of Kathleen Kelly, Division of Reptiles, Field Museum. Photo JCM.
The allopatric species described in the paper are associated with northern South American geography. Plica plica is associated with the Guiana Shield (Suriname, Guyana and Venezuela). A second species, P. caribeana sp. n. is associated with the Caribbean Coastal Range of Venezuela including Trinidad and Tobago. A third, very distinctive species, P. rayi sp. n. is associated with the Middle Orinoco at the eastern edge of the Guiana Shield.  Two other species, P. kathleenae sp. n. and P. medemi sp. n., are each based upon a single specimen, one from the Sierra Acarai Mountains of Guyana, and the other from southern Meta, Colombia. In addition to the morphological analyses, they sequenced 12S and 16S rDNA gene fragments from one Plica plica from Trinidad to assess its relationship and taxonomy to other mainland Plica. The results suggest Plica caribeana sp. n. likely diverged prior to the separation of Trinidad from Northern Venezuela. Isolation in the Caribbean Coastal Range during its rapid uplift in the late Miocene, combined with a marine incursion into northern Venezuela may have contributed to their genetic divergence from other populations.

Murphy JC, Jowers M. 2013. Treerunners, cryptic lizards of the Plica plica group (Squamata, Sauria, Tropiduridae) of northern South America. ZooKeys

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