Cingulados do Quaternário da Gruta da Lapinha, Iramaia, BA. Morfologia, Paleoecologia e Paleopatologia

Abstract

Xenarthra is one of the major clades of placental mammals; this superorder is subdivided into two orders, Cingulata and Pilosa. Although the cingulates are the oldest recorded xenarthrans and the most diverse group, intraordinal phylogenetic relationships are matter of discussion, especially when fossil species are considered. Recently, studies related to the Phylogeny, Morphology, Ontogeny, Paleopathology and Paleoecology have contibuted to the understanding of these animals that were more diverse taxonomically and morphologically during the Pleistocene and the early Holocene. Two families of herbivore cingulates differed during that time, Pampatheriidae and Glyptodontidae, due to the large size as well as the peculiar feeding habit that was herbivore grazer, in contrast to the living species. In Lapinha Cave, Iramaia, Bahia, Brazil, during an expedition in 2012 and 2014, remains of glyptodonts and pampatheres were found and collected. They are material of study in the present work that aimed: 1) to describe and compare the cingulate specimens from Lapinha Cave; 2) to analyze the developmental stages of the specimens; 3) to analyze the marks found on the osteoderms of the Holmesina specimens; 4) to perform the material dating; 5) to infer the paleoecological implications. Then the results and considerations were: 1) owning to the integrity of pampatheres from Lapinha Cave, new elements of the endoskeleton of this family are described, such as the hyoid apparatus, the complete axial skeleton and the pelvis. One of the results was the total axial length of the specimens (2.2 m), which is less than that that was estimated for other pampatheres. Also, with this work, a new species of Pampatheriidae is described for the Quartenary: Holmesina cryptae sp. nov.; 1.1) Holmesina cryptae and other pampatheres present co-ossifications in the post-cranial axial skeleton that are observed in other cingulates as well. It was also observed that the pampatheres possess the smallest number of lumbar vertebrae (only one) among the cingulates, however, show a number of iliac synsacral vertebrae greater than most xernathrans. 2) the number of vertebrae in these co-ossifications vary according to the developmental stage of these pampatheres; 2.1) Regarding the Glyptodontinae juveniles, when analyzing the material and comparing to which is in the literature is possible to identify them as very young Glyptotherium specimens, and new endoskeletal elements are described. The individuals that present teeth with pyramidal crown are indication of very young specimens that apparently still depended on parental care. 3) The causes of the marks found in Holmesina osteoderms are discussed in this work, and it is concluded that the main causes of the lesions present in various osteoderms of the three individuals analyzed occurred ante mortem and they were caused by ectoparasites as tungids and other dermatites, what is another evidence of this type of interation during the Quaternary in the Brazilian Intertropical Region. 4) By the radiocarbon dating of bioapatite method, the age of circa 21 ka was obtained which coincides with the SALMA Lujanian (Upper Pleistocene) and agrees with relative dating of H. paulacoutoi in Bahia, Brazil and Holmesina, Pampatherium and Tonnicinctus in the South of the continent. 5) The H. cryptae specimens lived in a time with a recurrent dry climate in Northeasern Brazil, possibly they represent declining populations. The search for water may have been the reason why the pampatheres entered in Lapinha Cave. 5.1) Iramaia, as well as the Chapada Diamantina region has a diversity of the species of animals from the Quaternary related to Brazilian Intertropical Region (BIR). The presence of more than one pampatheriid taxon in the same region, H. paulacoutoi, H. cryptae sp. nov. and Pampatherium humboldtii does not necessarily mean that they co-occurred contemporaneously in sympatry; it could represent uncontemporary expansion and contraction of species ranges due to climatic and environmental changes during the late Pleistocene.