Redescription of Tijubina pontei, an Early Cretaceous lizard (Reptilia; Squamata) from the Crato Formation of Brazil

Tiago R Simões

doi:10.1590/s0001-37652012005000001

Abstract

The record of Gondwanan Mesozoic lizards is very poor. Among the few species described for this region there is Tijubina pontei, an Early Cretaceous lizard from the Crato Formation (late Aptian) of northeast Brazil. Its description is very brief and lacks most of its diagnostic characters and clear delimitation from other lizard species. Here, a full redescription of the holotype is provided. T. pontei is demonstrated to be a valid species and a new diagnosis is provided with reference to Olindalacerta brasiliensis, a contemporary species of the Crato Formation. It lacks the posteroventral and posterodorsal processes of the dentary; the tibial/fibular length equals the femoral length and its posterior dentary teeth are robust, cylindrically based, unsculptured and bear no cuspids. The systematic position of T. pontei still needs further clarification, but preliminary analyses indicate that it lies in a rather basal position among the Squamata, similarly to O. brasiliensis.

Highlights

Lizard remains from the Mesozoic of Gondwanan derived continents are extremely rare
The published phylogenetic analyses of the Squamata considered for the systematic positioning of T. pontei within this group were chosen based on two main criteria
In O. brasiliensis the epipodials are 80% of the femoral length, whereas in T. pontei both are almost sized (98.9%)

Summary

Introduction

Lizard remains from the Mesozoic of Gondwanan derived continents are extremely rare. There is a proportionally higher number of snakes relative to lizards taxa in these regions and with a pattern opposite to that seen in Laurasia, where fossil lizards are much more common than fossil snakes (Krause . 2003). Among the few taxa described, there are the species Tikiguana estesi Datta & Ray 2006, from the Late Triassic (Carnian) of India; Bharatagama rebbanensis Evans, Prasad & Manhas 2002, from the Lower-Middle Jurassic of India; Paramacellodus difference is real or represents differential research efforts between areas in the northern and the southern hemisphere is still unknown (Evans 2003) To this day, the only valid species for South America are the four above ones from Brazil. Tijubina pontei was originally described as a teiid (BonfimJúnior and Marques 1997), as a basal Squamate (Bonfim-Júnior and Avilla 2002) and even as a Rhyncocephalia (Martill and Frey 1998) It is a wellpreserved specimen, but T. pontei material remains largely undescribed (Evans 2003); a redescription is necessary. This may allow Tijubina to have a better supported systematic positioning among the squamates and provide more data to future phylogenetic analyses, contributing to an advance in the understanding of the Cretaceous lizard fauna in Brazil

Methods

Findings

Discussion

Conclusion