Extinct tortoises from the Turks and Caicos Islands

Authors

  • Richard Franz Florida Museum of Natural History
  • Nancy A. Albury National Museum of The Bahamas
  • David W. Steadman Florida Museum of Natural History

DOI:

https://doi.org/10.58782/flmnh.tjmo7621

Keywords:

Turks and Caicos Islands, Bahamas, Lucayan Archipelago, tortoise, Chelonoidis, fossil, zooarchaeology, Holocene, new taxa

Abstract

We report abundant tortoise fossils from the Coralie Archaeological Site on Grand Turk Island (Turks Bank) and the non-cultural site of Indian Cave on Middle Caicos Island (Caicos Bank). These tortoises represent isolated populations of the extinct species Chelonoidis alburyorum, originally described from Abaco, The Bahamas. We describe the new material as two new subspecies, C. a. keegani on Grand Turk, and C. a. sementis on Middle Caicos. All fossil tortoises known thus far from The Bahamas and the Turks and Caicos Islands (= the Lucayan Archipelago) are likely referable to the polymorphic C. alburyorum. Lacking an epiplastral shelf distinguishes C. alburyorum from species of Chelonoidis in mainland South America and the Greater Antilles. Other diagnostic features of C. alburyorum are: extremely thin-shelled carapacial bones; flattened plastra (in presumed females only) or plastral concavities (mature males only), each with a series of horizontal boney ridges (bosses) on the internal surfaces; small to indistinct epiplastral apices; moderately sized to nearly absent xiphiplastral apices; and unique “bird-faced” entoplastral sculptures. A brief discussion follows on the possible sources, dispersal routes, environmental challenges, and ecological roles for the tortoises that colonized the West Indies.

many people working in a dig site

Downloads

Published

2020-08-05

How to Cite

Franz, R., Albury, N., & Steadman, D. (2020). Extinct tortoises from the Turks and Caicos Islands. Bulletin of the Florida Museum of Natural History, 58(1), 1–38. https://doi.org/10.58782/flmnh.tjmo7621

Issue

Section

Articles