Interpreting character variation in turtles: Araripemys barretoi (Pleurodira: Pelomedusoides) from the Araripe Basin, Early Cretaceous of Northeastern Brazil

Saulo Limaverde; Rodrigo Vargas Pêgas; Rafael Damasceno; Chiara Villa; Gustavo R Oliveira; Niels Bonde; Maria E C Leal

doi:10.7717/peerj.9840

Interpreting character variation in turtles: Araripemys barretoi (Pleurodira: Pelomedusoides) from the Araripe Basin, Early Cretaceous of Northeastern Brazil

PeerJ. 2020 Sep 29:8:e9840. doi: 10.7717/peerj.9840. eCollection 2020.

Authors

Saulo Limaverde^#¹, Rodrigo Vargas Pêgas^#², Rafael Damasceno³, Chiara Villa⁴, Gustavo R Oliveira³, Niels Bonde^{5

6}, Maria E C Leal⁷

Affiliations

¹ Centro de Ciências, Departamento de Geologia, Universidade Federal do Ceará, Fortaleza, Brazil.
² Laboratory of Vertebrate Paleontology and Animal Behaviour, Universidade Federal do ABC, São Bernardo do Campo, São Paulo, Brazil.
³ Laboratório de Paleontologia & Sistemática, Área de Ecologia, Departamento de Biologia, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil.
⁴ Laboratory of Biological Anthropology, Department of Forensic Medicine, Copenhagen University, Copenhagen, Denmark.
⁵ Section Biosystematics, Zoological Museum (SNM, Copenhagen University), Copenhagen, Denmark.
⁶ Fur Museum (Museum Saling), Fur, Denmark.
⁷ Faculty of Health, Aarhus University, Aarhus, Denmark.

^# Contributed equally.

Abstract

The Araripe Basin (Northeastern Brazil) has yielded a rich Cretaceous fossil fauna of both vertebrates and invertebrates found mainly in the Crato and Romualdo Formations, of Aptian and Albian ages respectively. Among the vertebrates, the turtles were found to be quite diverse, with several specimens retrieved and five valid species described to this date for the Romualdo Formation. There were also records of turtles from Ipubi and Crato Formations, mainly fragmentary material which precluded proper specific identification; however, Araripemys barretoi is supposed to occur on both Crato and Romualdo Formations. Here we describe thirteen specimens of A. barretoi-including the first description of an almost complete individual, bearing a skull, from the Crato Formation. We report a great amount of morphological variation, interpreted as being essentially of intraspecific nature, including individual, sexual and ontogenetic variation.

Keywords: Araripe; Araripemys; Cretaceous; Intraspecific variation; Ontogeny; Polymorphism; Sexual dimorphism.

Associated data

figshare/10.6084/m9.figshare.7700138.v1

Grants and funding

This work was supported by Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico (FUNCAP) and CNPq (CNPq/FUNCAP-DCR/305426/2014-1, DCR-0024-01186.01.00/14 and CNPq #131186/2017-5). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.