Nuevos registros fósiles de vertebrados terrestres para Las Llanadas, Sancti Spíritus, Cuba

Abstract

El depósito paleontológico Las Llanadas es un manantial con sedimento rico en materia orgánica. Estudios del sitio a principios del siglo XX, dieron a conocer materiales fósiles de perezosos, cocodrilos, tortugas terrestres, y jutías. Dos especies de perezosos, Acratocnus antillensis y Neocnus gliriformis, fueron nuevas para la ciencia. En el presente trabajo se dan a conocer nuevos registros fósiles de anuros, un reptil y aves para el depósito: Peltophryne empusus, Osteopilus septentrionalis, Cyclura nubila, Tyto alba, Buteogallus borrasi y Boromys ofella. Huesos recientes de Lithobates catesbeianus y Capromys pilorides se encontraron entre los materiales, lo que indica que el depósito se mantiene activo en la recepción de especímenes. De un total de 2030 piezas solo 3% pudo ser identificado taxonómicamente, debido al alto nivel de fragmentación.

Natural and anthropogenic factors as taphonomic agents in the differential preservation of paleontological remains from the fossil deposit “Las Llanadas”, Central Cuba

“…Torre (1910) mentions the coincident association of sloth remains with crocodile remains (Crocodylus pristinus = Crocodylus rhombifer), as was also observed in Ciego Montero, which made him think of a different environment from the current one. The same association was recently mentioned by Aranda et al (2017), who report 39 remains of crocodiles, among which some well-preserved teeth (Fig. 3n), vs. 698 remains of megalonichids.…”

“…Currently, the number of complete and very well preserved fossil material is limited (see Aranda et al, 2017), except for an almost complete radius of Capromys pilorides (Fig. 3a).…”

“…When considering the faunal composition of the paleontological remains found in "Las Llanadas" deposit (Torres, 1910;Brown, 1913;Matthew, 1931;Barbour, 1945;Matthew and Paula, 1959;Goldberg et al, 2017;Aranda et al, 2017) and the density of materials per zoological group, it is possible to infer the existence, at some point, of a lacustrine environment. Associated remains of crocodiles, chelonians, sloths, and hutias, among others (Torres, 1910, Brown, 1913Aranda et al, 2017) point to very well defined interspecific dynamics. The sea level would have to have been significantly higher than it is today for these conditions to prevail.…”

“…It constitutes, within the historical development of Cuban paleontology, the second most important fossil deposit of vertebrates for Cuban science. The remains extracted from it are referenced in various publications (Torre, 1910;Brown, 1913;Torre and Matthew, 1915;Torre, 1917;Matthew, 1918Matthew, , 1919Matthew, , 1931Matthew and Paula, 1959;Morgan et al, 1993;Arredondo, 1999;Aranda et al, 2017), allowing researchers to identify two of the three new genera of sloths (Torre and Matthew, 1915;Matthew, 1931) proposed at that time: Miocnus and Microcnus, which were subsequently systematically updated (in biological sense) as Acratocnus (Matthew and Paula, 1959) and Neocnus (White and MacPhee, 2001), respectively (see Silva et al, 2007: 12-15). This deposit was re-excavated by the Paleogeography and Paleobiology Group of the National Museum of Natural History of Cuba (MNHNC), in April 2013.…”

“…On the other hand, it is known that the taxonomic composition of the fossil deposit responds to very different past environments (Aranda et al, 2017), for this case, lacustrine type, therefore, assessing the paleogeographic evolution of the area is not a factor to dismiss. Sea level changes recorded between 140 kyr BP and almost the last stage of the Holocene (8-4 kyr BP) can help estimate a chronological period for the origin of the deposit.…”