ABSTRACT. The taxonomic identification of micromammals might be complicated when the study material is fragmented, as it is the case with pellets and fossil material. On the other hand, tooth morphology generally provides accurate information for species identification. Teeth preserve notably well, retaining their original morphology, unlike skulls and mandibles, which can get crushed or have missing parts. Here, we explored a geometric morphometrics approach (GM) to identify fragmented specimens of two sympatric Calomys Waterhouse, 1837 species -Calomys tener (Winge, 1888) and Calomys expulsus (Lund, 1841) -using the morphology of intact molars as the basis for identification. Furthermore, we included some specimens of uncertain taxonomic identification to test their affinities and the utility of the shape of the molar to identify incomplete specimens. We evaluated the variations in the shape of the first upper molar (M1) among 46 owl pellets specimens of Calomys, including C. expulsus (n = 15), C. tener (n = 15), and unidentified specimens treated as Calomys sp. (n = 16) through GM analysis using 17 landmarks. The data was explored using PCA, PERMANOVA, and Discriminant analyses over the Procrustes residuals matrix were applied to evaluate inter-and intraspecific shape differences. Also, we evaluated whether allometric shape differences could impact the data, but found no evidence of a correlation between size and shape. Our results support that shape differences in the M1 are effective for discriminating between C. tener and C. expulsus. Moreover, the unidentified specimens do not represent a third shape but could be identified with confidence either as C. tener or C. expulsus. Our results show that even with fragmentary materials, GM is a feasible and useful tool for exploring inter-specific shape differences and assisting in taxonomic identification as a complement to traditional qualitative description of diagnostic features in poorly preserved specimens.
Abstract.-Litopterna is represented in the Pleistocene of the Brazilian Intertropical Region by a monospecific genus of Macraucheniidae, Xenorhinotherium. Although most of the knowledge about this family is derived from the dentition, some dental features still remain unknown. This study describes the eruption sequence of permanent dentition and classifies the hypsodonty status of X. bahiense. The specimens studied are from Toca dos Ossos, a limestone cave located in Bahia State. We perform qualitative macroscopic analysis to describe the eruption dental sequence. Additionally, we perform quantitative analysis to determine the hypsodonty index. The dental eruption sequence of the juvenile specimen is M1, M2, I1, I2, M3, I3, P1, P2, P3, and P4. In addition, the analysis of tooth wear in adult specimens provides similar results. The hypsodonty index assigns a mesodont tooth crown for X. bahiense. The dental eruption sequence is most similar to a rapid-growth extant mammal. Moreover, our results do not support afrotherian-like delayed dental eruption to Litopterna. The hypsodonty index can be related to data on vegetation of the Brazilian Intertropical Region and the shape of the premaxilla of X. bahiense, both of which suggest a browsing diet for this macraucheniid.
The COVID‑19 pandemic imposes the biggest restrictions on access to morphological information housed in scientific collections, compromising the progress of scientific research. Even though it is not the first event to impose restrictions on access, it is undoubtedly the most global in range. Based on this, we discuss the barriers to access information and we show 3D technology as an important tool to create routes to mitigate the effects of future restrictions. In a global sphere, there are initiatives of inter-institutional integration and international networks focused on facilitating and disseminate the implementation of digitization tools and techniques to facilitate access to diverse biological information. Notwithstanding, when we speak in 3D technology in Latin American countries, as is well noted in Brazil, this type of progress is lacking, with only isolated initiatives from some laboratories and research centers that implement 3D digitization tools, but often as experimental uses. Moreover, recent events, such as the Museu Naciona fire and the mobility restriction imposed by the COVID‑19 pandemic, reinforce the need and urgency to discuss the virtualization of natural history collections in the national territory. In this sense, we recommend photogrammetry as a more accessible and versatile technology, which could be quickly implemented in curatorial procedures. We, also, have defined criteria to establish priorities for virtualizing the collection. The virtualization of the type specimens is an inevitable and necessary task to ensure their access and expansion of their safe preservation, as established by the ICZN, and should therefore be considered as a high priority, followed by reference specimens, which are frequently accessed. Finally, to ensure Latin America advances to levels similar to those observed in other continents, it is important to establish a collaborative network of museums and other research institutions.
-LATE PLEISTOCENE MEGAFAUNA FROM MATINA, BAHIA, BRAZIL: SYSTEMATIC, CHRONOLOGY AND PALEOECOLOGY. Fossils of Pleistocene mammals are well-represented in all Northeastern Brazil. In Bahia State these are found in caves and tanks fossiliferous outcrops. This paper focuses on the study of fossil mammals from the tank known as "Sítio Novo", in the municipality of Matina, Bahia. The research identifi ed seven taxa: Megatheriidae (Megatheriinae, Eremotherium laurillardi), Mylodontidae, Glyptodontidae, Macraucheniidae (Macraucheninae, Xenorhinotherium bahiense), Toxodontidae, Gomphotheriidae (Notiomastodon platensis) e Camelidae. This locality has one of the most diverse records of extinct mammalian fauna until now among the tanks found in Bahia. Based on the studied assemblage and dates of the same taxa from this and others assemblages, we suggest that the local fauna lived during the late Pleistocene.Key words: megafauna, mammals, paleoecology, chronology, late Pleistocene, Bahia.RESUMO -Os fósseis de mamíferos pleistocênicos são bem representados em todo o Nordeste do Brasil. No Estado da Bahia são encontrados em depósitos de cavernas e tanques. O presente trabalho tem como foco o estudo de fósseis de mamíferos provenientes do tanque "Sítio Novo", Município de Matina, Bahia. Foram identifi cados sete táxons: Megatheriidae (Megatheriinae, Eremotherium laurillardi), Mylodontidae, Glyptodontidae, Macrauchenidade (Macraucheninae, Xenorhinotherium bahiense), Toxodontidae, Gomphotheriidade (Notiomastodon platensis) e Camelidae. Este depósito é um dos mais diversos registros de mastofauna extinta, conhecido até o momento, para tanques da Bahia. Com base na assembleia estudada e em datações dos mesmos táxons desta e de outras localidades, pode-se sugerir que esta fauna viveu durante o Pleistoceno fi nal.
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