Review of thirty-two years of toothed whale strandings in Santa Catarina, southern Brazil (Cetacea: Odontoceti)

Marine mammal strandings provide valuable insights into local biodiversity. Strandings can be caused by both natural and anthropogenic factors. In the state of Santa Catarina, Southern Brazil, organized marine mammal collections started in the 1980s through opportunistic and non-systematic collection efforts, representing a record of over 30 years of marine biodiversity. This study aimed to perform a preliminary review of 32 years of stranding records within this region. The secondary aim was to elucidate the stranding dynamics of the three most commonly recorded species. A total of 460 records were obtained, representing 17 species of odontocetes. The species registered most frequently were the franciscana, Pontoporia blainvillei (Gervais & d' Orbigny, 1844) (n = 173), bottlenose dolphin, Tursiops truncatus (Montagu, 1821) (n = 100), and Guiana dolphin Sotalia guianensis (Van Bénéden, 1864) (n = 97). Most of the stranding records were observed in the second half of the year during the austral winter and spring. The apparent causes of death could not be determined for most of the specimens due to carcass decomposition. For the specimens in which the apparent cause of death could be determined, 27% of the strandings were compatible with anthropogenic interactions. While the focus of this study was a preliminary assessment of stranding data obtained through opportunistic collection, it is evident that future systematic monitoring efforts and stable networks of collaborators will generate more reliable coastal biodiversity inventories and will allow the knowledge of population dynamics of marine mammal species. In particular, for threatened and vulnerable species, or species with poor natural history data, strandings are a fundamental tool for the understanding of marine biodiversity. Ideally, future more refined analyses of stranding data should be used to inform conservation and management policies and to elucidate the biology and ecology of marine and coastal...

Review of thirty-two years of toothed whale strandings in Santa Catarina, southern Brazil (Cetacea: Odontoceti)

Marine mammal strandings provide valuable insights into local biodiversity. Strandings can be caused by both natural and anthropogenic factors. In the state of Santa Catarina, Southern Brazil, organized marine mammal collections started in the 1980s through opportunistic and non-systematic collection efforts, representing a record of over 30 years of marine biodiversity. This study aimed to perform a preliminary review of 32 years of stranding records within this region. The secondary aim was to elucidate the stranding dynamics of the three most commonly recorded species. A total of 460 records were obtained, representing 17 species of odontocetes. The species registered most frequently were the franciscana, Pontoporia blainvillei (Gervais & d' Orbigny, 1844) (n = 173), bottlenose dolphin, Tursiops truncatus (Montagu, 1821) (n = 100), and Guiana dolphin Sotalia guianensis (Van Bénéden, 1864) (n = 97). Most of the stranding records were observed in the second half of the year during the austral winter and spring. The apparent causes of death could not be determined for most of the specimens due to carcass decomposition. For the specimens in which the apparent cause of death could be determined, 27% of the strandings were compatible with anthropogenic interactions. While the focus of this study was a preliminary assessment of stranding data obtained through opportunistic collection, it is evident that future systematic monitoring efforts and stable networks of collaborators will generate more reliable coastal biodiversity inventories and will allow the knowledge of population dynamics of marine mammal species. In particular, for threatened and vulnerable species, or species with poor natural history data, strandings are a fundamental tool for the understanding of marine biodiversity. Ideally, future more refined analyses of stranding data should be used to inform conservation and management policies and to elucidate the biology and ecology of marine and coastal...(AU)

Numerical anomalies in the dentition of southern fur seals and sea lions (Pinnipedia: Otariidae)

Cases of dental agenesis, supernumerary teeth and dental losses are presented in three species of South American Otariids: Arctocephalus australis (Zimmermann, 1783), A. tropicalis (Gray, 1872) and Otaria flavescens (Shaw, 1800). For the first time, congenital and acquired dental anomalies were comparatively diagnosed in skull samples from southern Brazil and nearby areas. The skulls and mandibles were accessed in the scientific collection of mammals of the Federal University of Santa Catarina, southern Brazil. Agenesis was found only among maxillary post-canine teeth, especially the distal ones (PC/6), due to an evolutionary trend towards reduction of the number of post-canine teeth in this family. Maxillary and mandibular supernumerary teeth were found in A. australis and A. tropicalis, but their positioning is unrelated to cases regarding phylogenetic and evolutionary implications. Dental losses were found in all species and different stages of alveolar obliteration suggest that this process is common in Otariids and does not affect their survival. The investigation of congenital and acquired dental anomalies in pinnipeds can provide information on dental formula evolution in Pinnipeds and in the phylogenetic relationships among Carnivora.

Numerical anomalies in the dentition of southern fur seals and sea lions (Pinnipedia: Otariidae)

Cases of dental agenesis, supernumerary teeth and dental losses are presented in three species of South American Otariids: Arctocephalus australis (Zimmermann, 1783), A. tropicalis (Gray, 1872) and Otaria flavescens (Shaw, 1800). For the first time, congenital and acquired dental anomalies were comparatively diagnosed in skull samples from southern Brazil and nearby areas. The skulls and mandibles were accessed in the scientific collection of mammals of the Federal University of Santa Catarina, southern Brazil. Agenesis was found only among maxillary post-canine teeth, especially the distal ones (PC/6), due to an evolutionary trend towards reduction of the number of post-canine teeth in this family. Maxillary and mandibular supernumerary teeth were found in A. australis and A. tropicalis, but their positioning is unrelated to cases regarding phylogenetic and evolutionary implications. Dental losses were found in all species and different stages of alveolar obliteration suggest that this process is common in Otariids and does not affect their survival. The investigation of congenital and acquired dental anomalies in pinnipeds can provide information on dental formula evolution in Pinnipeds and in the phylogenetic relationships among Carnivora.

Numerical anomalies in the dentition of southern fur seals and sea lions (Pinnipedia: Otariidae)

Cases of dental agenesis, supernumerary teeth and dental losses are presented in three species of South American Otariids: Arctocephalus australis (Zimmermann, 1783), A. tropicalis (Gray, 1872) and Otaria flavescens (Shaw, 1800). For the first time, congenital and acquired dental anomalies were comparatively diagnosed in skull samples from southern Brazil and nearby areas. The skulls and mandibles were accessed in the scientific collection of mammals of the Federal University of Santa Catarina, southern Brazil. Agenesis was found only among maxillary post-canine teeth, especially the distal ones (PC/6), due to an evolutionary trend towards reduction of the number of post-canine teeth in this family. Maxillary and mandibular supernumerary teeth were found in A. australis and A. tropicalis, but their positioning is unrelated to cases regarding phylogenetic and evolutionary implications. Dental losses were found in all species and different stages of alveolar obliteration suggest that this process is common in Otariids and does not affect their survival. The investigation of congenital and acquired dental anomalies in pinnipeds can provide information on dental formula evolution in Pinnipeds and in the phylogenetic relationships among Carnivora.

Numerical anomalies in the dentition of southern fur seals and sea lions (Pinnipedia: Otariidae)

Cases of dental agenesis, supernumerary teeth and dental losses are presented in three species of South American Otariids: Arctocephalus australis (Zimmermann, 1783), A. tropicalis (Gray, 1872) and Otaria flavescens (Shaw, 1800). For the first time, congenital and acquired dental anomalies were comparatively diagnosed in skull samples from southern Brazil and nearby areas. The skulls and mandibles were accessed in the scientific collection of mammals of the Federal University of Santa Catarina, southern Brazil. Agenesis was found only among maxillary post-canine teeth, especially the distal ones (PC/6), due to an evolutionary trend towards reduction of the number of post-canine teeth in this family. Maxillary and mandibular supernumerary teeth were found in A. australis and A. tropicalis, but their positioning is unrelated to cases regarding phylogenetic and evolutionary implications. Dental losses were found in all species and different stages of alveolar obliteration suggest that this process is common in Otariids and does not affect their survival. The investigation of congenital and acquired dental anomalies in pinnipeds can provide information on dental formula evolution in Pinnipeds and in the phylogenetic relationships among Carnivora.

Numerical anomalies in the dentition of southern fur seals and sea lions (Pinnipedia: Otariidae)

Cases of dental agenesis, supernumerary teeth and dental losses are presented in three species of South American Otariids: Arctocephalus australis (Zimmermann, 1783), A. tropicalis (Gray, 1872) and Otaria flavescens (Shaw, 1800). For the first time, congenital and acquired dental anomalies were comparatively diagnosed in skull samples from southern Brazil and nearby areas. The skulls and mandibles were accessed in the scientific collection of mammals of the Federal University of Santa Catarina, southern Brazil. Agenesis was found only among maxillary post-canine teeth, especially the distal ones (PC/6), due to an evolutionary trend towards reduction of the number of post-canine teeth in this family. Maxillary and mandibular supernumerary teeth were found in A. australis and A. tropicalis, but their positioning is unrelated to cases regarding phylogenetic and evolutionary implications. Dental losses were found in all species and different stages of alveolar obliteration suggest that this process is common in Otariids and does not affect their survival. The investigation of congenital and acquired dental anomalies in pinnipeds can provide information on dental formula evolution in Pinnipeds and in the phylogenetic relationships among Carnivora.