Descrição morfológica e variações crânio-dentárias das espécies de morcegos do gênero Artibeus (Chiroptera: Phyllostomidae) depositadas na coleção de quiropterofauna da Universidade Estadual do Maranhão, campus Bacabal

Abstract

Bats of the family Phyllostomidae represent one of the most diverse groups within the order Chiroptera, currently comprising 61 genera and 230 species worldwide, with Brazil accounting for 43 genera and 96 species. The genus Artibeus Leach (1821), belonging to the subfamily Stemodermatinae, stands out for its wide distribution and high diversity in the Neotropical region, where this distribution is attributed to the genus individuals’ ability to adapt to different habitat types, as well as to their varied sizes. The Artibeus also presents taxonomic challenges, traditionally categorized into two groups: small and large Artibeus. Currently, ten species are recognized, distributed into three subgenera: Artibeus, Dermanura, and Koopmania, although there are divergences in the literature regarding this classification. These bats exhibit remarkable patterns of cranio-dental diversification, closely associated with dietary specializations, reflecting their versatility in resource exploitation. This study aimed to carry out morphological descriptions and analyze cranio-dental variations in specimens of the genus Artibeus, of the family Phyllostomidae, establishing relationships between these variations and habitat fragmentation processes in the Cocais Region, Maranhão, Brazil. Seventy specimens from the Morcegos dos Cocais collection were analyzed, with records of three recurrent species in the region: Artibeus lituratus (45), Artibeus planirostris (12) and Artibeus cinereus (13). Morphological and cranio-dental data were measured using a dynamometer and a caliper and subsequently organized in spreadsheets. Morphological differences among the species were observed. Morphometric measurements revealed that the body weight of Artibeus cinereus and Artibeus planirostris was lower than values reported in the literature. Cranio-dental analyses indicated important patterns for species delimitation on cranial parameters, based on nineteen characters submitted to Principal Component Analysis (PCA). The results showed relevant contributions between Dim1 - CMC = 10.8% and Dim2 - CCB = 10.8%, allowing the differentiation of species in the resulting graph. It was noted that A. cinereus occupied a more recessed position, indicating a smaller cranial dimension compared to A. lituratus and A. planirostris, which exhibited larger cranial proportions. This distinction highlights the importance of cranial size as a discriminating morphological characteristic between species, as well as specific differences in the postorbital constriction between A. lituratus and A. planirostris, and the presence or absence of the third molar in some individuals. The morphological and craniometric analyses provided valuable insights into the morphological variation and differentiation among species of the genus Artibeus in the Cocais Region.