Beak deviations in the skull of Franciscana dolphins Pontoporia blainvillei from Argentina.

The Franciscana dolphin Pontoporia blainvillei is characterized by a long rostrum, a feature that is shared with the families formerly classified as river dolphins (Pontoporiidae, Platanistidae, Iniidae, Lipotidae). Although there are occasional reports on the existence of beak deformations, very little published information exists describing this process. The object of the present study was to describe and quantify the beak anomalies of Franciscana dolphins from the coastal waters of Argentina. Of 239 skulls analyzed 12% showed beak deviations (BD), affecting the premaxillary-maxillary and dentary bones to different extents. The occurrence of BD in the dentary bone represented 58%, whereas premaxillary-maxillary BDs were observed in 14% of the studied specimens, while the complete rostrum (dentary, premaxillary and maxillary) was affected in 28% of the skulls. Dorsoventral axis BD was more frequent than lateral BD (48 and 38%, respectively), and double BD was only observed in the dentary bone. Most of the BD observed in this study could be classified as mild/moderate, and we assume that it did not affect the feeding activities of individuals; however, 2 specimens (<1%) showed a severe and complex curvature that probably did affect them. The cause of these anomalies (natural or anthropogenic origins) is unknown but may be related to important parasite loads, heavy metal and organic contaminants and plastic ingestion that could affect the coastal dolphin in different ways. A more detailed and thorough study of these cranial anomalies is necessary.

First record of an anomalously colored franciscana dolphin, Pontoporia blainvillei.

On October 2011, a newborn franciscana dolphin with an anomalously coloration was sighted in Babitonga Bay, southern Brazil. The calf was totally white. Besides the potential mother and newborn, the group also had the presence of another adult, who always was swimming behind the pair. Both adults had the typical coloration of the species, with the back in grayish brown. The group, composed by the white franciscana calf, his pontential mother and one more adult, was reported in five occasions. The group was always in the same area where it was first recorded and showed the same position during swimming. Between first and last sighting of the white calf (113 days) the color has not changed. This is the first case of a white franciscana dolphin. This coloration has never been reported despite the high number of dead franciscanas recovered each year along the distribution of the species, resulting from accidental capture in fishing nets. This fact leads us to believe that this is a very rare characteristic for this species. We considered the possibility that this franciscana could be an albino dolphin.

Case report of flipper anatomic anomaly of Sotalia guianensis from Sepetiba Bay, Rio de Janeiro.

The cetacean flipper consists of a soft tissue that encases most of the forelimb containing humerus, radius, ulna, carpals, metacarpals, and phalanges. Several studies have documented the typical cetacean's flipper anatomy, but only a few described digital anomalies and the most common are fusions and supernumerary such as polydactily and polyphalangy. The flippers of the Guiana dolphin, Sotalia guianensis have a falciform general aspect showing individual differences and marks produced by individual contact in social interactions that mainly occur on the posterior border. Here, we report for the first time a case of flippers with anatomical anomalies of loss of digits and deviation of radius of an adult S. guianensis from Baía de Sepetiba (22°54'-23°04', 43°36'-44°02'W), Rio de Janeiro, Southeastern Brazil.

Preenchendo lacunas em saúde de ecossistemas: estudo morfológico e de contaminantes nos botos-cinza (Sotalia guianensis, VAN BENÉDEN 1864) da costa norte do Brasil / Filling gaps in health ecosystems: morphological study and contaminants in estuarine dolphin (COSTERO, Van Beneden 1864) of the northern coast of Brazil

Os cetáceos odontocetos são predadores de topo na cadeia alimentar e algumas espécies, como o boto-cinza (Sotalia guianensis), apresentam um padrão de residência e fidelidade ao sítio. Ao longo da vida, por meio da alimentação, podem acumular elevadas concentrações de poluentes nos seus tecidos pelos processos de bioacumulação e biomagnificação. Essas características sustentam o potencial de S. guianensis como sentinela de saúde de ecossistemas costeiros. Os estudos sobre as populações do boto-cinza na norte do Brasil se iniciaram muito recentemente, o que acarretou uma lacuna de conhecimento nesta região. O objetivo deste estudo é caracterizar os estoques populacionais dos botos-cinza da costa norte do Brasil por meio de dados de morfometria craniana e cargas de contaminantes, adicionando informações para uma avaliação ampla do boto-cinza como sentinela de saúde de ecossistemas costeiros. (...) As análises de metais e organoclorados foram realizadas no Laboratório de Toxicologia da Seção de Meio Ambiente do Instituto Evandro Chagas em Belém-PA. Apesar da distribuição aparentemente contínua do boto-cinza na costa do Brasil, foi possível diferenciar as populações do estado do Pará daquelas do Maranhão, Piauí e Rio de Janeiro, por meio do estudo das medidas nos crânios. Por meio da análise de discriminantes, verificou-se que a população do Pará se separa completamente das populações do Rio de Janeiro, e parcialmente das populações do Maranhão e Piauí, com um padrão clinal no crescimento dos crânios no sentido norte/sul da distribuição. As concentrações de DDT em botos-cinza dos estuários da Costa Norte do Brasil são baixas em comparação com os outros estudos conduzidos no Brasil. As concentrações registradas, principalmente na região sudeste e sul, são mais de vinte vezes maiores que as observadas neste estudo. Estudos futuros poderão fazer uso do boto-cinza como um indicador para avaliar a saúde dos ecossistemas costeiros e o desenvolvimento de medidas de conservação, reduzindo o impacto antrópico sobre a espécie e o ambiente costeiro.

Some cetaceans are top predators in food chain and some species, such as the Guiana dolphin (Sotalia guianensis), show a pattern of residence and site fidelity. Throughout food, may accumulate great concentrations of pollutants in their tissues through bioaccumulation and biomagnification processes. These characteristics support the potential of S. guianensis as sentinel health of coastal ecosystems. Studies on populations of the estuarine dolphin in northern Brazil have started very recently, led to a knowledge gap in this region. The aim of this study is to characterize the population of Guiana dolphin of northern coast of Brazil, through cranial morphometric data and levels of contaminants, adding information to a broad assessment of the Guiana dolphin as a sentinel health of coastal ecosystems. (...) Analyses of metals and organochlorines were performed at the Laboratory of Toxicology, Environment Section of Instituto Evandro Chagas in Belém-PA. Despite the apparently continuous distribution of the Guiana dolphin off the coast of Brazil, it was possible to differentiate populations from those of the state of Pará, Maranhão, Piauí and Rio de Janeiro, through the study of measures on the skulls. Through discriminant analysis, it was found that the population of Pará is completely separates the population of Rio de Janeiro, and partly of Maranhão and Piauí, with a clinal pattern in the growth of skulls in a north/south distribution. Levels of THg and MeHg on the north coast of Brazil are small compared to the concentrations previously reported for the species throughout its distribution. DDT concentrations in harbor porpoises, gray estuaries of the northern coast of Brazil are low compared with other studies conducted in Brazil. The concentrations recorded, mainly in southeastern and south, are more than twenty times higher than those observed in this study. Future studies may make use of the Guiana dolphin as a tool to assess the health of coastal ecosystems and the development of conservation measures, reducing the human impact on the species and the coastal environment.

True hermaphroditism: first evidence of an ovotestis in a cetacean species.

An immature unilateral hermaphrodite common dolphin (Delphinus delphis) was found stranded on the southwest coast of the UK. The external phenotype was that of a female, but internally there was one ovotestis, containing both ovarian follicles and testicular tubular elements, and a contralateral ovary. Ovarian portions of the ovotestis appeared normal and demonstrated follicular development, whereas the testicular tissue exhibited hypoplasia and degeneration. This is the first reported case of an ovotestis in a cetacean species.

Anomalias ósseas congênitas em sotalia guianensis (mammalia, cetacea, delphinidae) da costa centro-norte do estado do Rio de Janeiro / Congenital bone defects in guiana dolphin, sotalia guianensis (mammalia, cetacea, delphinidae) in the northcentral coast of Rio de Janeiro state, Brazil

Carcaças de botos-cinza Sotalia guianensis (van Bénéden, 1864) foram recuperadas entre 20 de agosto de 2001 e 13 de fevereiro de 2006, na costa centro-norte fluminense. A maior parte delas (85 por cento) entre Barra de São João (22º35'S 41º59'W) e Quissamã (22º06'S 41º28'W). Foram estudadas as colunas vertebrais dos 20 exemplares que apresentavam mais de 60 por cento das vértebras presentes. A coleção é formada por 75 por cento de animais imaturos, e todos os esqueletos mostram alterações tafonômicas mínimas. Duas categorias de anomalias congênitas foram diagnosticadas, ambas relacionadas ao desenvolvimento do mesoderma paraxial. A sétima vértebra cervical (C7) foi a única afetada, as costelas cervicais e o não fechamento do arco neural atingiram 15 (75 por cento) dos indivíduos analisados, dos quais três (15 por cento) apresentam ambas as anomalias. Nove (45 por cento) indivíduos apresentaram costelas cervicais uni ou bilateral, e nove (45 por cento) indivíduos apresentaram não fechamento do arco neural; em todos os casos as vértebras contíguas eram normais. A ocorrência de anomalias nesta série do Rio de Janeiro é maior do que as referidas na literatura brasileira para outras séries de Sotalia do Amazonas, Ceará e Santa Catarina. A série de Sotalia descrita vem de uma região do litoral muito limitada e provavelmente representa uma população local. As costelas cervicais são geneticamente determinadas e podem estar concentradas por uma condição de grande proximidade biológica entre os animais; o não fechamento do arco pode ter também um componente ambiental, a ser investigado futuramente.

Carcasses of Guiana dolphins, Sotalia guianensis (van Bénéden, 1864) were recovered from August 20, 2001 to February 13, 2006 along the north-central coast of Rio de Janeiro state. Most of the animals (85 percent) were found between Barra de São João (22º35'S 41º59'W) and Quissamã (22º06'S 41º28'W). We studied the vertebral columns of all the 20 specimens that had more than 60 percent of the vertebrae preserved. The series has 75 percent of immature animals and all skeletons displayed a minimum of taphonomic changes. Two categories of congenital anomalies were diagnosed, both related to the development of the paraxial mesoderm. The seventh cervical vertebra (C7) was the only affected; the cervical ribs and the cleft neural arches were present in 15 (75 percent) of the individuals, three (15 percent) of which had both anomalies. Nine (45 percent) individuals had unilateral or bilateral cervical ribs, and nine (45 percent) individuals had cleft neural arches; the contiguous vertebrae were normal in every case. The frequency of these anomalies was higher in that Rio de Janeiro series than in other Sotalia series previously reported in the Brazilian literature for Amazonas, Ceará and Santa Catarina States. The present Sotalia series here described comes from a very limited coastal region probably representing a local population. The cervical ribs are genetically defined and may be concentrated because of a condition of close biological proximity among the animals; the cleft arch could also be determined by environmental factors, to be investigated in the future.

First confirmed record of Feresa attenuata (Delphinidae) for the Northern Brazilian Coast / Primeiro registro confirmado de Feresa attenuata (Delphinidae) para o litoral norte do Brasil

In Brazil only one confirmed stranding is known from an emaciated specimen collected along the southeastern coast. The aim of this work is to report a recent record of a pygmy killer whale from the coast of Maranhão State, northern Brazil. On 22 October 2005, through regular surveys conducted by Projeto Cetáceos do Maranhão team, a beach-worn skull of a pygmy killer whale was found on the Mangue Seco beach, at Caju Island, Maranhão State. The specimen was identified through peculiar features, such as a short beak, 11 teeth per row in the maxile and the distance between the anterorbital notch and the end of the toothrow. This stranding suggests that pygmy killer whales may use oceanic waters close to Maranhão continental shelf. This is the second confirmed stranding of F. attenuata for the Brazilian Coast and the first along the northern coast. The present record increases our poor knowledge on the cetacean fauna of the northern Brazilian coast.

No Brasil somente um exemplar de Feresa attenuata foi coletado ao longo da costa sudeste. O objetivo deste trabalho é registrar o recente encalhe da orca-pigméia para a costa do Maranhão, litoral norte do Brasil. Em 22 de outubro de 2005, através de monitoramentos regulares conduzidos pelo Projeto Cetáceos do Maranhão, um crânio do exemplar de F. attenuata foi encontrado na praia do Mangue Seco, na Ilha do Caju, Estado do Maranhão, Brasil. O espécime foi identificado através de características peculiares, como o rostro curto, 11 pares de dentes na maxila e pela distancia entre o anterorbital e o término dos alvéolos dentares. Este encalhe sugere que a orca-pigméia pode usar águas oceânicas próximas à plataforma continental do Maranhão. Este é o segundo registro de encalhe confirmado para F. attenuata para a costa brasileira e o primeiro para a costa norte. O presente estudo contribui com o pouco conhecimento sobre os cetáceos na costa norte do Brasil.