Paleoherpetology and The Anatomical Record

Abstract

The field of paleontology has long been dominated by charismatic species, such as ever-imposing dinosaurs and intriguingly anthropomorphic primates. However, alongside each dinosaur and primate lived a variety of other fossil species, often smaller reptiles, which typically receive dramatically less public and scientific attention. Nevertheless, paleoherpetology, the study of fossil reptiles (typically used to refer to non-dinosaurian fauna), provides an important framework for understanding the broader context of past ecosystems. Over the past several years, paleoherpetological studies have been the subject of a considerable number of articles in The Anatomical Record (AR).

In this special issue of The Anatomical Record, we celebrate paleoherpetology. Specifically, the volume brings together a collection of papers on topics ranging from crocodyliforms to turtles to lizards. The issue has been skillfully Guest Edited by two experts in the field of paleoherpetology, Drs. Adán Pérez-García and Francisco Ortega (Figure 1). Adán is a researcher at the Evolutionary Biology Group of the National University of Distance Education (UNED, Madrid, Spain), and a Senior Lecturer (“Profesor Titular de Universidad”) at the Faculty of Sciences of that University. His main field of research is the evolutionary history of turtles, both European forms and taxa related to them that inhabited other continents, especially Africa. He is currently active in the study of Cenozoic forms of turtles, while he also continues to work with Mesozoic taxa, and in the study of Mesozoic and Cenozoic fossil sites with reptiles. He has participated in several projects that involve the analysis of reptile faunas, especially from the Mesozoic, and is the primary researcher of more than 10 projects, involving researchers from various European countries and other continents. He has been the director of several paleontological excavation campaigns, and the author of more than 150 scientific papers and more than 300 conference presentations. He has described more than 35 new genera and more than 35 new species of reptiles, most of them turtles, but also crocodiles and sauropterygians.

Francisco is a Professor at the Faculty of Sciences of UNED (Madrid) and the Principal Investigator of the Evolutionary Biology Research Group at UNED, focusing on the evolutionary history of Mesozoic reptiles, particularly crocodiles and dinosaurs, along with their ecosystems. He has authored over 100 publications in scientific and technical journals, primarily concentrating on the Upper Jurassic of Portugal, as well as the Lower and Upper Cretaceous and the Paleogene of Spain. Furthermore, he has contributed to the development of museum and museographic projects in Spain. His research efforts extend to various paleontological projects in Spain, Portugal, Niger, and Argentina, involving participation in nearly 100 excavations and more than twenty national and international research projects. We at The Anatomical Record wish to express our sincere thanks to Drs. Pérez-García and Ortega for their excellent work on this issue.

The first true reptiles appeared in the fossil record around 320 million years ago and have since undergone dramatic diversification and evolution. Unique anatomical adaptations allowed turtles and other paleoherp fauna to survive the Cretaceous-Paleogene (K-Pg) extinction event that wiped out the non-avian dinosaurs. Over the years, papers in AR have described many important paleoherpetological findings. This introductory editorial will briefly report some of the most significant prior special volumes and publications on paleoherpetological topics in the AR.

In 2022, AR published its second largest volume ever, “The Age of Crocodilians and their kin: Their anatomy, physiology and evolution” (Holliday & Schachner, 2022; Laitman & Smith, 2022). The Special Issue began with early Triassic crocodylomorphs (Bestwick et al., 2021; Melstrom et al., 2021; Parker et al., 2021; Ruebenstahl et al., 2022; von Baczko et al., 2021) and extended through the radiation of crocodyliforms during the rest of the Mesozoic (Bowman et al., 2021; Cowgill et al., 2021; Dumont Jr. et al., 2020; Fernandez & Herrera, 2021; Nieto et al., 2021; Wilberg et al., 2021). Finally, it concluded by presenting new research into Cenozoic crocs (Brochu et al., 2022; Pochat-Cottilloux et al., 2021).

In 2023, AR published a special volume of papers resulting from the 2022 Turtle Evolution Symposium (TES) (Smith & Laitman, 2023; Sterli & Vlachos, 2023). TES is a regular international conference that brings together researchers studying different aspects of the evolutionary history of turtles, from their origin and early evolution until recent times. Topics relating to fossil turtles ranged from osteohistology (Guerrero & Pérez-García, 2023; Pereyra, 2023) to neuroanatomy (Martín-Jiménez & Pérez-García, 2023; Smith et al., 2023) to descriptions of new species (Brinkman et al., 2023; Gentry et al., 2023; Joyce et al., 2023; Maniel et al., 2023; Pérez-García, 2023; Vlachos et al., 2023) to documenting new fossil turtle occurrences (Boneta Jiménez et al., 2023; Saltsidou et al., 2023).

A recent Special Issue on paleohistology of pseudosuchians yielded a number of exciting papers. Topics have ranged from models to estimate body mass in fossil taxa (Woodward et al., 2024) to a review of paleohistology across Pseudosuchia (Scheyer, 2024).

In addition to Special Issues, AR has also recently published numerous standalone papers on paleoherpetology. Studies have focused on the evolution of amphisbaenian squamates (Salvino et al., 2024), as well as new materials of other fossil lizards (Loreal et al., 2024). New crocodyliform taxa have been described (Noto et al., 2019), along with studies on the ontogeny of baurusuchids (dos Martins Santos et al., 2025). Papers have described anatomical variation in extant turtle morphology with relation to fossil turtle taxa (Evers et al., 2023; Hermanson et al., 2024; Miller et al., 2024) and discussed variation among fossil species (Adrian et al., 2022). Tooth replacement in mesosaurs has been described (Carlisbino et al., 2024). Modern squamates have also been studied as a way to interpret the fossil record (e.g., Allemand, Abdul-Sater, et al., 2023; Allemand, López-Aguirre, et al., 2023; Maliuk et al., 2024).

In all, paleoherpetological studies provide important evolutionary and paleoenvironmental information. They fill in the missing gaps in the fossil ecosystems between the more widely studied taxa, such as non-avian dinosaurs and mammals. We hope you enjoy the volume of exciting papers on paleoherpetology in this Special Issue.

Heather F. Smith: Writing – original draft; investigation; visualization; conceptualization. Jeffrey T. Laitman: Writing – original draft; writing – review and editing.