INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
Presence of the extinct Lizard Paradracaena (Teiidae) in the Middle Miocene of the Peruvian Amazon
FRANÇOIS, PUJOS; ADRIANA M., ALBINO; PATRICE, BABY; JEAN-LOUP, GUYOT
JOURNAL OF VERTEBRATE PALEONTOLOGY
The Society of Vertebrate Paleontology
Lugar: Lawrence; Año: 2009 p. 594 - 594
In October 2004, a unique multidisciplinary scientific mission, organized by the Hybam program and comprising geophysicists, hydrologists, and naturalists (geologists, paleontologists and botanists), explored the 900km of the Napo River between the cities of Coca (Ecuador) and Iquitos (Peru). The aim of this mission was to obtain new information on Amazonian geodynamics through a better understanding of hydrologic and geologic factors. The geological-paleontological team inspected 87 outcrops of which only ten were found to include fossil vertebrate remains. In Ecuador, fossiliferous sites of Colhuehuapian SALMA in age (Lower Miocene) are located between the towns of Misahualli and Pantoja and have principally yielded chelonian remains. In Peru, vertebrate remains, from the Pebas Formation, are more abundant, especially near the city of Iquitos. One fossiliferous site (Na069, Fig. 1) preserves an abundant, middle Miocene (Laventan SALMA) vertebrate fauna (Antoine et al. 2006) including terrestrial and aquatic vertebrates. Fishes are represented by abundant teeth and caudal spines of Chondrichthyes Myliobatiformes Potamotrygonidae, isolated teeth of the Sarcopterygii Lepidosiren sp. and a Characiform Serrasalmidae, several spines and vertebrae of various siluriformes Bagridae and a rib of a manatee Trichechidae. The reptilian fauna is constituted by teeth and post-cranial elements of two crocodiles, the gigantic alligateroid Purussaurus sp. and the gavialid Gryposuchus sp., abundant fragmentary scute osteoderms and skeletal elements of chelonians (cf. Podocnemis sp.), an indeterminate snake vertebra, and a dentary of the large teiid lizard Paradracaena sp., which is the focus of this report. Lizards are represented since the Cretaceous in South America, mostly by fragmentary remains. Within the Teiidae, the genus Tupinambis, known since the Lower Miocene of Patagonia, is the oldest member in South America (Brizuela and Albino, 2004). Nowadays, the Teiidae constitute a clade of Neotropical lizards, with an important geographical distribution in South America, Central America, and Islands, and relatively few species signaled in North America (Uetz and Hallerman, 2007). The ten modern genera that constitute this clade are distributed in the Teiinae and Tupinambinae. Four modern genera, Callopistes, Crocodilurus, Dracaena, and Tupinambis, and the extinct Paradracaena, compose the Tupinambinae. In 1961, Estes described the extinct species Dracaena colombiana from the Middle Miocene of the Magdalena River valley (Colombia) and allocated other teiid specimens from the same locality and age to the extant Tupinambis cf. T. teguixin. Later, based on these last remains, Estes (1983) described the new species T. huilensis. Additional specimens from the Villavieja and La Victoria Formations, in the Colombian localities of La Venta and Coyaima, have permitted to round up all these remains in a new tupinambine genus and species, Paradracaena colombiana (Sullivan and Estes, 1997). The mammalian fauna of these formations is characteristic of the Middle Miocene Laventan SALMA. The Colombian Miocene teiids from La Victoria Formation also include a single specimen of Tupinambis sp. (Sullivan and Estes, 1997). In this work, we describe a dentary assigned to the teiid lizard Paradracaena, exhumed from Middle Miocene sediments in the Napo River (Peru).