BIMONTHLY BULLETIN of the DEPARTMENT of ENVIRONMENT ‘S TERRESTRIAL RESOURCES UNIT FOSSIL VERTEBRATES FROM THE CAYMAN ISLANDS

By: Gary Morgan, New Mexico Museum of Natural History

The Cayman Islands are a hot spot for The first person to discover vertebrate paleontology. Specifically, the Caymans fossils in the Cayman Islands was Lord are known for vertebrate fossils, Moyne, who found fossils of a large including crocodiles, , and rodent in a cave at Stake Bay on Cayman mammals, dating to about the last Brac in 1937. The next year, Bernard 15,000 years, or the Pleistocene (also Lewis from the Institute of Jamaica, a known as the Ice Age) and Holocene member of the legendary Oxford epochs in geological terms. Fossils have University Biological Expedition to the been found in two types of deposits in Cayman Islands, collected additional the Caymans; loose sediments in caves fossils of a large rodent in a cave on on Cayman Brac and and Cayman Brac. In 1964, Thomas Patton mangrove peat deposits and “cow from the Florida State Museum (now wells” on Grand Cayman. Only a few the Florida Museum of Natural History) fossils have been recovered from small at the University of Florida explored caves on . Cayman Brac in search of fossil vertebrates.

The author (left) and Greg McDonald (right) excavate fossils from a cave on Grand Cayman in 1976.

Flicker Bulletin # 29 – FEB / MAR 2017 He discovered large samples of fossil Until the late 1970s, all vertebrate reptiles, birds, and mammals in two fossils from the Cayman Islands had caves on Cayman Brac, since named been recovered from caves on Cayman Patton’s Fissure and Pollard Bay Cave. Brac and Grand Cayman. That changed dramatically with two important As a beginning graduate student at the discoveries on Grand Cayman. In 1979, University of Florida (UF) in 1975, I was Edward and Robert Materne found a recruited by Patton to study the fossil large number of darkly stained bones vertebrates from the Cayman Islands for protruding from piles of organic my Masters Thesis. Having grown up in sediment (peat) excavated from a a small town in Ohio, I was thrilled with mosquito control canal in a mangrove the opportunity to do field work and swamp north of George Town. Later research on a tropical island group in that same year, the Maternes took the . My first field trip to the those bones to the U. S. National Cayman Islands was in 1976, with fellow Museum of Natural History, part of the UF students Greg McDonald and Nina Smithsonian Institution in Washington, Thanz, which began a 20 year DC, where I was working at the time. paleontological odyssey that included Much to my surprise, almost their entire four more trips to the Caymans to sample of fossils belonged to crocodiles, collect fossils in 1979, 1980, 1986, and including a nearly complete skull –see 1993. below.

Fossil skull of the Cuban crocodile (Crocodylus rhombifer) from the Crocodile Canal site, Grand Cayman. Dorsal (top) view on left, ventral (bottom) view on right.

Flicker Bulletin # 29 – FEB / MAR 2017 This site has since been named the The Ice Age fossil vertebrates from the Crocodile Canal. Also in the late 1970s, Cayman Islands represent an interesting Grand Cayman residents Rolin Chisholm mix of that still occur in the and Ira Thompson collected a second islands, including frogs, lizards, snakes, large sample of crocodile bones, from birds, and bats, together with crocodiles dark organic sediments removed from a and numerous species of birds and cow well on Chisholm’s property near mammals no longer found in the North Side (see below). Cow wells are Caymans. Some of these species are small, water-filled depressions in the completely extinct, while others are lime