A new species of extinct Late Quaternary giant tortoise from Hispaniola

Abstract

Insular giant tortoise diversity has been depleted by Late Quaternary extinctions, but the taxonomic status of many extinct populations remains poorly understood due to limited available fossil or subfossil material, hindering our ability to reconstruct Quaternary island biotas and environments. Giant tortoises are absent from current-day insular Caribbean ecosystems, but tortoise remains from Quaternary deposits indicate the former widespread occurrence of these animals across the northern Caribbean. We report new Quaternary giant tortoise material from several cave sites in Pedernales Province, southern Dominican Republic, Hispaniola, representing at least seven individuals, which we describe as Chelonoidis marcanoi sp. nov. Although giant tortoise material was first reported from the Quaternary record of Hispaniola almost 35 years ago, tortoises are absent from most Quaternary deposits on the island, which has been studied extensively over the past century. The surprising abundance of giant tortoise remains in both vertical and horizontal caves in Hispaniola’s semi-arid ecoregion may indicate that this species was adapted to open dry habitats and became restricted to a habitat refugium in southeastern Hispaniola following climatic-driven environmental change at the Pleistocene-Holocene boundary. Hispaniola’s dry forest ecosystem may therefore have been shaped by giant tortoises for much of its evolutionary history.

Fossil Land Tortoises (Testudines: Testudinidae) from the Dominican Republic, West Indies, with a Description of a New Species

“…See tables 1 and 2 for lists of shell and skull measurements. We also examined and compared the tortoise shell fragments and postcranial bones from the Marcano collection reported by Franz and Woods (1983), the Turks and Caicos Islands specimens (Franz et al, 2000) and compared them with the description and images of C. marcanoi (Turvey et al, 2017), C. cubensis (Leidy, 1868) (see images in Williams, 1950), C. sombrerensis (Leidy, 1886), and C. monensis (Williams, 1952). General morphological assessments for South American relatives are available in Franz and Franz (2009 We follow the terminology used in Bramble (1971) and Franz and Franz (2009), for shell measurements and the names for carapacial and plastral bones, sutures, scutes, and sulci.…”

“…Bayaguana (Franz and Woods, 1983); 3. Barahona area (Turvey et al, 2017). Dotted line delineates the border between Haiti and the Dominican Repub¬ lic; the heavy dashed line indicates the Enriquillo-Plantain Garden Fault.…”

“…Chelonoidis marcanoi Sample: A recent description of a giant tortoise, Chelonoidis marcanoi, from the Dominican Republic, by Turvey et al (2017), was based on fragmentary limb bones (6 humeri, 2 femora) and 4 shell fragments (3 epiplastra with evidence of gular scutes, 1 partial hyoplastron or hypoplastron). Their sample represented at least seven individuals from five caves in Pedernales Province, in the southwestern part of the country.…”

“…Anguilla;20. Barbados. A second collection of tortoise fossils is now available from five dry caves on the Barahona Peninsula, Pedernales Province, in the southwestern Dominican Republic, consisting of limb bones and shell fragments; this collection was described as Chelonoidis marcanoi by Turvey et al, (2017). The material is housed in the Museo Nacional de Historia Natural "Prof. Eugenio de Jesus Marcano" (MNHNSD), Santo Domingo, Dominican Republic, and the Natural History Museum (NHMUK), London.…”

The Plight of Reptiles as Ecological Actors in the Tropics

“…We may never know, because these 1.5 m, 36 kg animals are functionally extinct in the wild (Ding et al, 2001). This fate is yet another to be added to the long list of vanished or functionally extinct reptiles already cited in this text, that continues to grow every year (Turvey et al, 2017).…”