Cranial asymmetry in odontocetes: a facilitator of sonic exploration?

Directional cranial asymmetry is an intriguing condition that has evolved in all odontocetes which has mostly been associated with sound production for echolocation. In this study, we investigated how cranial asymmetry varies across odontocete species both in terms of quality (i.e., shape), and quantity (magnitude of deviation from symmetry). We investigated 72 species across all ten families of Odontoceti using two-dimensional geometric morphometrics. The average asymmetric shape was largely consistent across odontocetes - the rostral tip, maxillae, antorbital notches and braincase, as well as the suture crest between the frontal and interparietal bones were displaced to the right, whereas the nasal septum and premaxillae showed leftward shifts, in concert with an enlargement of the right premaxilla and maxilla. A clear phylogenetic signal related to asymmetric shape variation was identified across odontocetes using squared-change parsimony. The magnitude of asymmetry was widely variable across Odontoceti, with greatest asymmetry in Kogiidae, Monodontidae and Globicephalinae, followed by Physeteridae, Platanistidae and Lipotidae, while the asymmetry was lowest in Lissodelphininae, Phocoenidae, Iniidae and Pontoporiidae. Ziphiidae presented a wide spectrum of asymmetry. Generalized linear models explaining magnitude of asymmetry found associations with click source level while accounting for cranial size. Using phylogenetic generalized least squares, we reconfirm that source level and centroid size significantly predict the level of cranial asymmetry, with more asymmetric marine taxa generally consisting of bigger species emitting higher output sonar signal, i.e. louder sounds. Both characteristics theoretically support foraging at depth, the former by allowing extended diving and the latter being adaptive for prey detection at longer distances. Thus, cranial asymmetry seems to be an evolutionary pathway that allows odontocetes to devote more space for sound-generating structures associated with echolocation and thus increases biosonar search range and foraging efficiency beyond simple phylogenetic scaling predictions.

Osteochondromatosis (multiple cartilaginous exostoses) in an immature killer whale Orcinus orca.

An immature killer whale Orcinus orca found dead on the southeastern Brazilian coast had multiple bone proliferations: on the skull, vertebrae, hemal arches, and ribs. The bony formations were characterized as multiple osteochondromas, as defined by osteochondromatosis. The diagnosis was based on macroscopic and radiographic observations. These benign osseocartilaginous tumors affect young individuals and grow until skeletal maturity is achieved. Case reports of this condition, besides humans, include other mammals, with most reports for pets and domestic mammals such as cattle, and a report in a fossil canid (Hesperocyon) from the Oligocene. The etiology, diagnosis, developmental characteristics, and occurrence of osteochondromas are distinct among different species. This report describes the first case of multiple osteochondromas in a wild cetacean.

Pathology in the appendicular bones of southern tamandua, Tamandua tetradactyla (Xenarthra, Pilosa): injuries to the locomotor system and first case report of osteomyelitis in anteaters.

BACKGROUND: The southern tamandua, Tamandua tetradactyla (Linnaeus, 1758), is the most common species of anteater. Even though much is known about its ecology, behavior, and parasites, there is very limited information about bone diseases in Tamandua and other anteaters. Here, we examined postcranial skeletons of 64 T. tetradactyla museum specimens covering most of the material available in Brazilian collections. RESULTS: The following bone diseases were identified for the first time in Tamandua and other extant and fossil vermilinguans: osteophytes, osteitis, osteoarthritis, periostitis, exostoses, enthesopathies, and a severe chronic pyogenic osteomyelitis associated with fistulae, cloacae (pus), bone loss, and neoformation processes. Musculoskeletal reconstruction revealed that an old specimen was restricted to terrestrial locomotion due to osteopathological processes that impaired its climbing. CONCLUSIONS: New osteopathological informations are presented for T. tetradactyla, favoring a better understanding of the expression of some bone diseases in wild animals. In addition, the diagnosis of these bone diseases in living anteaters provides useful information for studies on animal health and welfare, as well as contributing to the more effective recognition of paleodiseases in fossil xenarthrans.

Alterações e lesões dentárias em muriquis (Brachyteles, Spix 1823), (Atelidae - Primates): ambiente, dieta e condições de vida / Changes and dental injuries in spider monkeys (Brachyteles, Spix 1823), (Atelidae - Primates): environment, diet and living conditions

O presente trabalho foi realizado com primatas do gênero Brachyteles que se distribuem pelo bioma da Mata Atlântica, e tem suas espécies ameaçadas de extinção. Foram analisadas as condições dentárias de espécimes esqueletonizados levando em consideração a dieta e suas condições de vida nos ambientes de origem, devido à estreita relação que a saúde da boca e dos dentes guarda com a saúde do indivíduo de uma forma geral. As séries estudadas foram provenientes do Departamento de Vertebrados do Museu Nacional / Universidade Federal do Rio de Janeiro e do Museu de Primatologia do Centro de Primatologia do Rio de Janeiro. Os registros das alterações e lesões dentárias foram feitos por representações gráficas em odontograma específico para o gênero Brachyteles, através de observações macro e microscópicas. Não foram observadas em ambas as séries variação de número de dentes, persistência de decíduo e lesões de cárie. Alterações / lesões sugestivas de hipoplasias e crazing foram observadas, mas seus diagnósticos não foram conclusivos. Entre as alterações observadas temos a variação de posição ocorrendo em 23,08 por cento dos espécimes da série do Museu Nacional, frente aos 33,33 por cento dos espécimes da série do Centro de Primatologia. A deposição de cálculo dentário atingiu consideravelmente os espécimes do Centro de Primatologia, com 66,67 por cento apresentando esta alteração, enquanto que no Museu Nacional foram atingidos apenas 7,69 por cento dos espécimes. Dentre as lesões traumáticas, levando em consideração a quantidade de espécimes atingidos e o grau de severidade das lesões, no Centro de Primatologia também foram mais frequentes e severas as lesões, com 100 por cento dos espécimes apresentando lesões de microfraturas e fissuras, 83,33 por cento apresentando fratura no esmalte e 16,67 por cento apresentando fratura com exposição da câmara pulpar. Nos espécimes do Museu Nacional, as lesões de microfraturas, fissuras, fratura de esmalte, fratura de coroa sem e com exposição da câmara pulpar, ocorreram respectivamente, em 84,62 por cento, 46,15 por cento, 80,77 por cento, 3,85 por cento e 3,85 por cento dos espécimes. As lesões de desgaste no esmalte e na dentina acometeram todos os espécimes de ambas as séries, entretanto a frequência de dentes atingidos foi maior no Museu Nacional, e o desgaste que alcançou a câmara pulpar, ocorreu apenas nesta série, em 7,69 por cento dos espécimes, os quais são provenientes de vida livre, diferente da série do Centro de Primatologia, que é composta por exemplares de vida livre e exemplares que viveram parte ou toda a vida no cativeiro. As alterações e lesões encontradas nas séries foram abordadas a partir dos seus aspectos de comportamento e dieta nos ambientes em que viveram.

This study was conducted with primates of the genus Brachyteles that are distributed by the Mata Atlântica biome, and has its endangered species. Dental conditions of skeletons were analyzed considering the diet and living conditions in their original environments, due to the close relationship that the health of the mouth and teeth has with one's health in general. The series studied were from the Department of Vertebrate of the Museu Nacional / Universidade Federal do Rio de Janeiro and the Museu de Primatologia of the Centro de Primatologia do Rio de Janeiro. The records of the changes and dental lesions were made by graphical representations in specific odontogram to the genus Brachyteles through macro and microscopic observations. Were not observed in both series variation in number of teeth, persistence of deciduous and caries lesions. Alterations / lesions suggestive of hypoplasia and crazing were observed, but their diagnoses were inconclusive. Among the alterations we observed the change of position occurred in 23,08 por cent of specimens from the Museu Nacional of the series, compared to 50 por cent of the specimens of series Centro de Primatologia. The deposition of dental calculus considerably specimens reached the de Primatologia, 66,67 por cent with this alteration, while the Museu National were only achieved 7,69 por cent of specimens. Among the traumatic injuries, taking into consideration the amount of affected specimens and the severity of injuries, in the Centro de Primatologia the injuries were also more frequent and severe, with 100 por cent of specimens showing lesions of microfractures and fissures, 83,33 por cent presenting fractured in the enamel and 16,67 por cent with crown fracture exposing of the pulp chamber. Specimens in the Museu Nacional, injuries of microfractures, fissures, enamel fracture, crown fracture with and without exposing of the pulp chamber, occurred respectively, in 84,62 per cent, 46,15 per cent, 80,77 per cent, 3,85 per cent and 3,85 per cent of the specimens. The lesions of wear to enamel and in the dentin attack all specimens of both series, however the frequency of affected teeth was higher in the Museu Nacional, and the wear that has reached the pulp chamber, occurred only in this series, in 7,69 per cent of specimens, which are from free life, different from the series of the Centro de Primatologia, which consists of free-living specimens and specimens that lived part or whole life in captivity. The changes and lesions found in the series were discussed from aspects of their behavior and diet in the environments in which they lived.

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.