ABSTRACT. A detailed analysis of the interactions between Tursiops /runco/us (Montagu, 1821) and the artisanal fishing of mullets (MugU spp.) is presented at two localities in the south of Brazil: Laguna (Santa Catarina) and Imberrramandai (Rio Grande do Sui). Its behavioral strategies and the advantages of their association are re-described and quantified based on the success of the capture and on the selectivity of the prey sizes. The mullets are the main resource involved (92 % to 75%) both at numerical level and as biomass. Twenty individuals of Tursiops /runcollls participated in the interactions in Laguna and 9 in Imberrramandai. The participation and learning of calves is also reported.

Chiroptera is the second largest order of mammals (KALKO 1998). In tropical forests, this group accounts for nearly 40 to 50% of the total mastofauna, thus strongly affecting richness and diversity patterns (ESTRADA & COATES-ESTRADA 2001). Moreover, bats occupy a variety of trophic niches, including frugivore, nectarivore, carnivore, sanguivore, piscivors, and insectivore species (FLEMING et al. 1972). Due to their considerable feeding plasticity, this group interacts with a broad spectrum of organisms (BERNARD & FENTON 2007), playing a fundamental role in the maintenance of ecological processes (KALKO 1998, BERNARD 2001, FALCÃO et al. 2003). Because of the great ecological importance of bat assemblages, several studies have been conducted focusing on their structure (

-We analyzed 63 cases of dental anomalies from 62 specimens of a total sample of 516 specimens of the Atlantic population of South American sea lions, Otaria byronia de Blainville, 1820. The anomalies were represented by 53 cases of missing upper post-canine 6 (second molars), seven cases of maxillary or mandibular extra teeth, two cases of "dentes geminati" and one case of reduced teeth. Considering a phylogenetic framework where all otariid species and basal Pinnipedimorpha are included, missing post-canine 6 could be related to evolutionary trends in Otariidae towards a progressive reduction and loss of teeth (agenesis). The occurrence of the upper post-canine 6 in Otaria Péron, 1816 as in Phocarctos Peters, 1866 is usually regarded as a primitive character. Alternatively, when adopting another cladistic procedure, this could be interpreted as a taxic atavism at the base of Otaria/Phocarctos clade. Extra-mandibular teeth are related to a concrete case of spontaneous atavism in the dentition of Otaria byronia, in retrogression to ancient groups like the Miocene pinnipediform Pteronarctos Barnes, 1989. The other anomalies -maxillary extra teeth, "dentes geminati" and reduced teeth -are caused by some disturbance on the epigenetic system underlying dental morphogenesis leading to duplication, coalescence or duplication and reduction of the dental germ, respectively. Dental formula in Otaria byronia shows a high degree of variability and this variability must be considered in the light of their phylogenetic relationships and their evolutionary history. The ecological approach suggests that dental anomalies do not affect longevity, and are unrelated to dietary items or environmental disturbances, but these points need more careful studies.Resumo -Foram analisadas 63 anomalias dentárias em 62 espécimes de uma amostra total de 516 indivíduos da população Atlântica do leão marinho sul-americano Otaria byronia de Blainville, 1820. As anomalias foram representadas por 53 casos de pós-caninos 6 (segundos molares) ausentes, sete casos de dentes extranumerários maxilares/mandibulares, dois casos de dentes geminados, e um caso de dente reduzido. Considerando um contexto filogenético onde são incluídas todas as espécies de otarídeos e também Pinnipedimorpha basais, a ausência do pós-canino 6 pode estar relacionada às tendências evolutivas de redução e perda desse dente (agênese). A ocorrência dos sextos pós-caninos superiores em Otaria Perón, 1816 e em Phocarctos Peters, 1866 é, usualmente, considerada um caráter primitivo. Alternativamente, adotando-se um procedimento cladístico distinto, isto poderia ser interpretado como um atavismo táxico na base do clado Otaria/Phocarctos. Dentes extranumerários mandibulares são considerados casos concretos de atavismos espontâneos na dentição de Otaria byronia, em retrogressão a grupos ancestrais como o pinipedimorfo do Mioceno Pteronarctos Barnes, 1989. As outras anomalias -dente extranumerário maxilar, dente geminado e dente reduzido -são causadas por algum distúrbio no sis...

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ABSTRACT. Geographica l d istribution and morphological analysis of Artibeus lituratusOlfers andArtibeusfimbriatusGray (Chiroptera, Phyllostom idae) in Rio Grande do Sul, Brazil. A study has been made on the geographical distribution and comparative externa I and cranial morphological analysis ofArlibeus liluratus Olfers, 1818 and Artibeusfimbrialus Gray, 1838 (Chiroptera, Phyllostomidae) in the state of Rio Grande do Sul, Brazil. A. liluralus and A. jill1brialus were found to be sympatric in the state n0l1h to the " Planície Costeira", in the "Depressão Central", in the hillsides of "Serra Geral", and in the northern region ofthe state, areas previously covered by forests . The southernmost point for Artibeus Leach, 1821 distribution is 30° South, and A. liluratus and A. jimbriallls are the two species found more to the south. The two species studied do not show sexual dimorphism as to exte1l1al characteristics. Cranial measurements revealed significant differences between males and fema les of A. liluralus in mandible length, which was significantly 1arger in females(p <5%), and between males and females of A.jimbrialus, in the length ofthe set oflower teeth and in the externa1 width between the cingula of canine teeth, which were significantly larger in males (p<5%). No further morphological cranial differences were found between genders of both species. A. liluralus and A. jimbrialus can be externally distinguished by size, for A. liluralus is larger than A. jimbrialus as concerns ali external dimensions ana!ysed except for the tibia length (p<5%). The two species can also be differentiated by pelage colour, hair length, and facial stripes appearance. ln the skull, a number of difterences were found in rostrum format, in the deveJopmental degree ofsupraorbital and post-orbita! crests and pre-orbita! and post-orbital processes, and in severa! cranial dimensions analysed. KEY WORDS. Phyllostomidae, Arlibeus liluralus, Arlibeus jimbriatus, distribution, morphology, South Brazil Os morcegos do gênero Artibells Leach, 1821 (Phyllostomidae, Stenodermatinae) distribuem-se desde o México até o norte da Argentina e sul do Brasil