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NEW TORTOISE FOSSILS FROM THE BAHAMIAN ARCHIPELAGO, WITH COMMENTS ON TWO NEW SPECIES OF CHELONOIDIS (TESTUDINIDES: TESTUDINIDAE) FROM ABACO AND GRAND TURK 

This investigation is a collaboration with Nancy Albury (Abaco Friends of the Environment, Abaco, The Bahamas). 

SUMMARY.  More tortoise fossils were collected recently from blue holes, dry caves, beach deposits, and archeological sites on the Little Bahama Bank, Great Bahama Bank, Crooked-Acklins Bank, Mayaguana Bank, Turks Bank, and Caicos Bank in the Bahamian archipelago.  All of these tortoise fossils are placed in the Neotropical genus Chelonoidis and are considered to be closely-related to the recently-described Chelonoidis alburyorum Franz & Franz from Sawmill Sink on Great Abaco on the Little Bahama Bank in the northern Bahamas.  Two of the new fossil populations represent new species. One is a giant form from Lost Reel and other nearby flooded caves on Abaco that has a carapace length about twice the size as C. alburyorum.  It is considered to be much older than the late Holocene C. alburyorum. This large form is probably mid-late Pleistocene in age, although this timing cannot be verified by radiometric dating because of the lack of datable carbon. The second population is a smaller species, about half the size of C. alburyorum, from an archaeological site (GT-4) on Grand Turk in the Turks and Caicos Islands.  This species may have become extinct in the early historic period, based on radiometric dates and its association with human occupation sites.  Fossil tortoises from other banks will be described but not named. With better material and greater scrutiny, some of these populations may eventually prove to represent undescribed taxa.  Because of its array of fossil tortoises, crocodiles, hutias, and birds together with unique living vertebrate assemblages, the Bahamian archipelago is proving to be another island-based, evolutionary hot spot, like the Galapagos Islands.










Above,
 Chelonoidis alburyorum Franz and Franz from the late Holocene of Sawmill Sink, Abaco, The Bahamas



Left,
Working with team at Sawmill Sink