Late Quaternary Fossil Mammals from the Cayman Islands, West Indies

Abstract

Abundant fossils of nesophontid lipotyphlan insectivores and capromyid rodents have been collected from late Quaternary deposits on the Cayman Islands, an island group separated by a major marine barrier from other Caribbean landmasses and isolated from anthropogenic impacts until the arrival of Columbus in 1503 CE. These collections have not previously been formally described. Using morphological and ancient DNA approaches, we document three new taxa of extinct endemic terrestrial mammals from this island group: Nesophontes hemicingulus (Grand Cayman and Cayman Brac), Capromys pilorides lewisi (Grand Cayman, Little Cayman, and Cayman Brac), and Geocapromys caymanensis (Grand Cayman and Cayman Brac). Morphometric comparisons with other extinct and living West Indian mammals indicate that the biogeographic origins of all three new taxa are from source populations on Cuba. Ancient DNA data indicate very low sequence divergence of Capromys pilorides lewisi from mainland Cuban C. pilorides (only 0.5% across the entire mitogenome). Using probabilistic analysis of existing and new radiometric dates, we calculate an estimated extinction date of 1700 CE (95% confidence interval = 1632-1774 CE) for the Cayman Brac Capromys population. This result suggests that at least one endemic Cayman terrestrial mammal population survived for well over a century following first European arrival in the Cayman Islands. The West Indies lost nearly all its species-rich late Quaternary land mammal fauna during the late Holocene due to direct or indirect human impacts, and this study provides a new baseline to understand the magnitude of human-caused mammal extinctions during the recent past. FIG. 1. Cayman Islands, showing geographical position and paleontological localities on Grand Cayman, Cayman Brac, and Little Cayman.

Ancient DNA and high-resolution chronometry reveal a long-term human role in the historical diversity and biogeography of the Bahamian hutia

“…When late Quaternary fossils and extinct/extirpated species are considered, the similarities expand to include such species as a crocodile (Crocodylus rhombifer), caracara (Caracara creightoni), barn owl (Tyto pollens), woodpecker (Xiphidiopicus percussus), kingbird (Tyrannus cubensis), and others. Cuba is the center of extinct and extant capromyine diversity, whether for Capromys or Geocapromys 26,27 . Morphological data suggest that G. ingrahami and two extinct species, G. columbianus from Cuba and G. caymanensis from Cayman Brac and Grand Cayman, form a group within Geocapromys, distinct from G. brownii of Jamaica and the recently extinct Swan Island hutia G. thoracatus 27,54 .…”

“…Cuba is the center of extinct and extant capromyine diversity, whether for Capromys or Geocapromys 26,27 . Morphological data suggest that G. ingrahami and two extinct species, G. columbianus from Cuba and G. caymanensis from Cayman Brac and Grand Cayman, form a group within Geocapromys, distinct from G. brownii of Jamaica and the recently extinct Swan Island hutia G. thoracatus 27,54 . It is likely that the most recent common ancestor between Cuban Geocapromys sp.…”

<b>Nuevo registro de parto séxtuple de jutía conga</b> <i>Capromys pilorides</i><b> (RODENTIA: CAPROMYIDAE) en Cuba</b>

“…Allen, 1911, de Isla de la Juventud; C. p. doceleguas Varona, 1980, del archipiélago Jardines de la Reina; y C. p. gundlachianus Varona, 1983, del archipiélago de Sabana (Upham y Borroto-Páez, 2017;Woods et al, 2001). No está amenazada de extinción y, como las seis especies restantes de jutías de Cuba, es endémica (Amaro-Valdés, 2012; Berovides-Álvarez y Comas- González, 1991;Soy y Silva, 2008;Turvey et al, 2017); sin embargo, su endemismo podría ser cuestionable con la descripción reciente de una subespecie fósil, C. p. lewisi, que habitó en las Islas Caimán (Morgan et al, 2019). Esta especie constituye la jutía de mayor plasticidad ecológica y de la que existe más información sobre su biología, tanto en condiciones naturales como en cautiverio, en particular sobre su reproducción (Silva-Taboada et al, 2007), lo que contradice el calificativo de "roedor poco conocido" dado por Tolson y Petersen (2008).…”

Collagen Sequence Analysis Reveals Evolutionary History of Extinct West Indies Nesophontes (Island-Shrews)

“…2005 ), or as many as five species from Cuba (additionally including N. longirostris Anthony 1918 , 1919 ), N. superstes ( Fischer 1977 ) and N. submicrus ( Arredondo 1970 ) depending on the author ( Silva et al. 2007 ), and three species from Hispaniola ( N. paramicrus , N. hypomicrus , and N. zamicrus ; Miller 1929), along with one recently described species recorded from the Cayman Islands ( N. hemicingulus , Morgan et al. 2019 ), present on both Cayman Brac and Grand Cayman.The Cayman Island species has been considered as being derived from one of the Cuban species, but “probably N. micrus , based on several shared dental features” ( Morgan 1994 ).…”