Contrasting patterns of preservation in a Jamaican cave

Abstract

AbstractRed Hills Road Cave, Jamaica is a remnant of a karstic feature quarried away during road building. It is the most important site for Late Pleistocene terrestrial palaeontology on the island. The site is c. 30 ka old. Many taxa were washed in during hurricanes and tropical storms, either as dead carcasses or live organisms that drowned as the cave filled with water. The invertebrate fauna includes snails and arthropods; none are obligate cave dwellers. The 62 species of land snails are the most diverse of any Jamaican cave; operculate taxa may be preserved with the operculum in situ. Arthropods include the only fossil millipedes, isopods and insects (fly puparia, beetle elytra) in the Jamaican fossil record, in addition to land crabs. Millipedes and isopods are well preserved because of a diagenetically early coating of calcite cement. The exoskeletons of these groups contain a small, but significant, calcite component not found in insects, spiders and scorpions. The vertebrate fauna remains understudied, but include: a rodent and three species of bat; a flightless ibis and various other birds; and reptile and amphibian remains. In contrast to the arthropods, the vertebrates are invariably disarticulated apart from rare crania, jawbones retaining teeth and bones that are fused in life. A dead millipede could be coated in calcite when floating in the cave immediately after death; a dead vertebrate carcass would have to rot to expose its bones after the cave dried out and would, most likely, disarticulate before or during the next inundation.