Análise crânio - dentária dos morcegos (Mammalia , Chiroptera ) em fragmentos florestais da região dos Cocais , Bacabal-MA

Abstract

The bats constitute about 25% of the mammal species, and the order Chiroptera currently has more than 1450 known species of bats. For Brazil, there are 181 species of bats, grouped into 68 genera and 9 families: Emballonuridae, Phyllostomidae, Mormoopidae, Noctilionidae, Furipteridae, Thyropteridae, Natalidae, Molossidae, and Vespertillionidae. The skull of bats is a structure with great phenotypic plasticity, shaped to meet the feeding demands of the species. The cocais region is characterized by the abundance of babassu palms, located at the intersection of the Amazon and Cerrado biomes of Maranhão, considered a characteristic landscape of the state. The order Chiroptera has an important ecological factor, and despite few studies conducted, the presence of several species of this order is notable in the Cocais Region, whether carnivorous, insectivorous, nectarivorous, hematophagous, or frugivorous. The present study aimed to analyze the cranio-dental morphology of bats in forest fragments of the Cocais Region, Bacabal, Maranhão. The collections were carried out in different peri-urban areas of the municipality of Bacabal, in forest fragments of the cocais region, having as a criterion the 4 points regionally known as Sítio dos Padres, Fazendinha, Lacerdão, and Barreirinha, using mist nets. The skull of each specimen was removed by buccal folding and skin cleaning by manual means. After cleaning, the skulls were bleached with 10% hydrogen peroxide, taken to an oven at a temperature of 37°C for drying, and subsequently identified with numbering and individually packaged in clean jars. Eleven cranial measurements were taken for each specimen (mm), using a digital caliper with a precision of 0.01mm.70 specimens distributed in four families were considered: Phyllostomidae (10 species), Emballonuridae (three species), Vespertilionidae (one species), Molossidae (tow species), and Noctilionidae (one species). Carollia affines perspicillata was the most abundant species. The average measurements of Platyrrhinus lineatus, Phyllostomus discolor, Artibeus lituratus and Desmodus rotundus were lower than those described in the literature. These results can be explained by the degradation of the environment where these bats live and the high cranial plasticity. The Total Skull Length (CMC) measurement contributed the most with respect to Dim1, which explains 80.5% of the data variation, followed by Dim2, which contributed 7.7%, totaling 88.2% of the sum of the two dimensions among all related measurements. The Principal Component Analysis (PCA), generated through the data matrix, revealed a delimitation of the species, separating the sample units by trophic guild.