TY - JOUR
T1 - The cuban crocodile (crocodylus rhombifer) from late quaternary underwater cave deposits in the Dominican cny DOM
AU - Morgan, Gary S.
AU - Albury, Nancy A.
AU - Rímoli, Renato
AU - Lehman, Phillip
AU - Rosenberger, Alfred L.
AU - Cooke, Siobhán B.
N1 - Funding Information:
We are grateful to the members of the Dominican Republic Speleological Society, in particular, Victoria Alexandrova, Cristian Pittaro, and Dave Pratt, who have worked closely with Phillip Lehman, one of the coauthors of this paper, to collect large samples of vertebrate fossils from underwater caves in the Dominican Republic, which are now permanently housed in the Museo del Hombre Dominicano (MHD). Phillip Lehman, together with Cristian Pittaro, collected most of the crocodile fossils described here. Oleg Shevchuk discovered Oleg’s Bat Cave (= Oleg’s Bat House). G.S.M. and N.A.A. thank Stephan Oldenburg for showing them Oleg’s Bat Cave, and Victoria Alexandrova (with P.L.) for helping to arrange their trip to the cave. The owners of the property, Frank and Jack Guerrero Herrera, gave us permission to visit the cave. Christian Martinez, director of the MHD, and Renato Rímoli made arrangements for G.S.M. and N.A.A. to visit the collections of the museum to study the crocodile fossils described here. Juan Almonte provided access to an important sample of modern skulls of the American crocodile from the Dominican Republic in the Museo Nacional de Historia Natural República Dominicana, Professor Eugenio Jesus Marcano. Mary Ann Joca assisted with cataloging crocodile fossils in the MHD. Brian Albury helped with computer graphics. Alexander Hastings and David Steadman provided helpful comments on the manuscript. This research was funded in part by a Waitt grant from the National Geographic Society to A.L.R. and an Exploration Fund Award from the Explorers Club to S.B.C.
Publisher Copyright:
© American Museum of Natural History 2018.
PY - 2018/12
Y1 - 2018/12
N2 - Late Quaternary fossils representing a locally extinct population of the Cuban crocodile (Crocodylus rhombifer) are reported from two underwater caves in the Dominican cny DOM A large fossil sample of C. rhombifer, from Oleg's Bat Cave near Bavaro in the southeastern Dominican cny DOM, consists of four nearly complete skulls, numerous isolated cranial elements and mandibles, and more than 100 postcranial bones representing most of the skeleton. These fossils were collected from a completely submerged portion of the cave at a depth of 11 m and about 100 m from the nearest entrance. A skull, mandibles, and two vertebrae of a Cuban crocodile were also found in a second cave called Ni-Rahu, northeast of Santo Domingo. We identify the fossil crocodile skulls from the Dominican cny DOM as Crocodylus rhombifer because they share the following characters with modern skulls of C. rhombifer from Cuba (as well as fossil skulls from Cuba, the Bahamas, and Cayman Islands): Short, broad, and deep rostrum; large orbits; convex nasals along the midline (midrostral boss); prominent swelling on the lacrimals anterior and medial to the orbits; low but obvious ridges extending anteriorly from the lacrimals to the nasals and posteriorly from the lacrimals to the prefrontals and frontals, outlining a distinct diamond- or rhomboid-shaped structure; strongly concave interorbital region and cranial roof; high, narrow ridges on the internal margins of the orbits, extending from the prefrontals to the frontals and posteriorly to the postorbitals; prominent ridges along the lateral margins of the cranial roof on the postorbitals and squamosals, terminating as noticeable protuberances on the posterolateral corners of the squamosals; premaxillary/maxillary suture on the palate essentially horizontal or transverse to the long axis of the skull at the level of the first maxillary tooth; 13 teeth in the maxilla. Certain aspects of the ecology and anatomy of living Crocodylus rhombifer in Cuba, and carbon isotope data from fossil crocodile bones from both the Dominican cny DOM and the Bahamas, indicate that the Cuban crocodile is a terrestrially adapted predator. The fossil deposits in Oleg's Bat Cave and other underwater caves in the Dominican cny DOM lack freshwater vertebrates, such as fish and turtles, but contain abundant samples of hystricognath rodents, small ground sloths, and other terrestrial vertebrates, including large land tortoises, that apparently were the primary prey of the crocodiles. Bats are abundant in the fossil deposits in Oleg's Bat Cave, and may have been an additional food source. Bone collagen from a tibia of C. rhombifer from Oleg's Bat Cave yielded an AMS radiocarbon date of 6460 ±30 ryrBP (equivalent to 7320 to 7430 cal yrBP). The chronology for the local extinction of C. rhombifer in Hispaniola is currently unknown, except to document the presence of this species in the eastern Dominican cny DOM in the early Holocene. Radiocarbon dates and historical records confirm that Cuban crocodiles survived into the period of European colonization (post-1492) in the Bahamas and on Grand Cayman. The only species of crocodile currently found in Hispaniola, the American crocodile (C. acutus), occurs in coastal marine habitats and in two inland brackishwater lakes: Lago Enriquillo in the Dominican cny DOM and the nearby Etang Saumâtre in Haiti. C. acutus has no fossil record in Hispaniola or elsewhere in the West Indies, suggesting that this species may be a very recent (late Holocene) immigrant in the Antillean region. Crocodylus rhombifer has one of the most limited geographic ranges of any living crocodylian species, known only from freshwater swamps in south-central Cuba and the Isla de Juventud (Isla de Pinos) off the southwestern coast of Cuba. Locally extinct or extirpated populations of C. rhombifer from fossil deposits in the Dominican cny DOM, Grand Cayman, and the Bahamas document a considerably wider distribution for this species during the Late Quaternary.
AB - Late Quaternary fossils representing a locally extinct population of the Cuban crocodile (Crocodylus rhombifer) are reported from two underwater caves in the Dominican cny DOM A large fossil sample of C. rhombifer, from Oleg's Bat Cave near Bavaro in the southeastern Dominican cny DOM, consists of four nearly complete skulls, numerous isolated cranial elements and mandibles, and more than 100 postcranial bones representing most of the skeleton. These fossils were collected from a completely submerged portion of the cave at a depth of 11 m and about 100 m from the nearest entrance. A skull, mandibles, and two vertebrae of a Cuban crocodile were also found in a second cave called Ni-Rahu, northeast of Santo Domingo. We identify the fossil crocodile skulls from the Dominican cny DOM as Crocodylus rhombifer because they share the following characters with modern skulls of C. rhombifer from Cuba (as well as fossil skulls from Cuba, the Bahamas, and Cayman Islands): Short, broad, and deep rostrum; large orbits; convex nasals along the midline (midrostral boss); prominent swelling on the lacrimals anterior and medial to the orbits; low but obvious ridges extending anteriorly from the lacrimals to the nasals and posteriorly from the lacrimals to the prefrontals and frontals, outlining a distinct diamond- or rhomboid-shaped structure; strongly concave interorbital region and cranial roof; high, narrow ridges on the internal margins of the orbits, extending from the prefrontals to the frontals and posteriorly to the postorbitals; prominent ridges along the lateral margins of the cranial roof on the postorbitals and squamosals, terminating as noticeable protuberances on the posterolateral corners of the squamosals; premaxillary/maxillary suture on the palate essentially horizontal or transverse to the long axis of the skull at the level of the first maxillary tooth; 13 teeth in the maxilla. Certain aspects of the ecology and anatomy of living Crocodylus rhombifer in Cuba, and carbon isotope data from fossil crocodile bones from both the Dominican cny DOM and the Bahamas, indicate that the Cuban crocodile is a terrestrially adapted predator. The fossil deposits in Oleg's Bat Cave and other underwater caves in the Dominican cny DOM lack freshwater vertebrates, such as fish and turtles, but contain abundant samples of hystricognath rodents, small ground sloths, and other terrestrial vertebrates, including large land tortoises, that apparently were the primary prey of the crocodiles. Bats are abundant in the fossil deposits in Oleg's Bat Cave, and may have been an additional food source. Bone collagen from a tibia of C. rhombifer from Oleg's Bat Cave yielded an AMS radiocarbon date of 6460 ±30 ryrBP (equivalent to 7320 to 7430 cal yrBP). The chronology for the local extinction of C. rhombifer in Hispaniola is currently unknown, except to document the presence of this species in the eastern Dominican cny DOM in the early Holocene. Radiocarbon dates and historical records confirm that Cuban crocodiles survived into the period of European colonization (post-1492) in the Bahamas and on Grand Cayman. The only species of crocodile currently found in Hispaniola, the American crocodile (C. acutus), occurs in coastal marine habitats and in two inland brackishwater lakes: Lago Enriquillo in the Dominican cny DOM and the nearby Etang Saumâtre in Haiti. C. acutus has no fossil record in Hispaniola or elsewhere in the West Indies, suggesting that this species may be a very recent (late Holocene) immigrant in the Antillean region. Crocodylus rhombifer has one of the most limited geographic ranges of any living crocodylian species, known only from freshwater swamps in south-central Cuba and the Isla de Juventud (Isla de Pinos) off the southwestern coast of Cuba. Locally extinct or extirpated populations of C. rhombifer from fossil deposits in the Dominican cny DOM, Grand Cayman, and the Bahamas document a considerably wider distribution for this species during the Late Quaternary.
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U2 - 10.1206/3916.1
DO - 10.1206/3916.1
M3 - Review article
AN - SCOPUS:85059386614
SN - 0003-0082
VL - 2018-December
SP - 1
EP - 56
JO - American Museum Novitates
JF - American Museum Novitates
IS - 3916
ER -