Low incidence of atrial septal defects in nonmammalian vertebrates.

The atrial septum enables efficient oxygen transport by separating the systemic and pulmonary venous blood returning to the heart. Only in placental mammals will the atrial septum form by the coming-together of the septum primum and the septum secundum. In up to one of four placental mammals, this complex morphogenesis is incomplete and yields patent foramen ovale. The incidence of incomplete atrial septum is unknown for groups with the septum primum only, such as birds and reptiles. We found a low incidence of incomplete atrial septum in 11 species of bird (0% of specimens) and 13 species of reptiles (3% of specimens). In reptiles, there was a trabecular interface between the atrial septum and the atrial epicardium which was without a clear boundary between left and right atrial cavities. In developing reptiles (four squamates and one crocodylian), the septum primum initiated as a sheet that acquired perforations and the trabecular interface developed late. We conclude that atrial septation from the septum primum only results in a low incidence of incompleteness. In reptiles, the atrial septum and atrial wall develop a trabecular interface, but previous studies on atrial hemodynamics suggest this interface has a very limited capacity for shunting.

New tomographic contribution to characterizing mesosaurid congenital scoliosis.

The presence of a pathology in the vertebral column of the early Permian mesosaurid specimen ZPAL R VII/1, being one of the oldest amniotic occurrences of congenital scoliosis caused by a hemivertebra, was recently recognized. Here we provide CT data to further characterize the phenomenon. The affected hemivertebra is wedged (incarcerated) between the preceding and succeeding vertebrae. The neural canal is misshapen but continuous and the number of dorsal ribs on each side of the specimen corresponds with the number of the vertebrae, documenting its congenital (homeobox-related) derivation.

Fusion of cervical vertebrae from a basal archosauromorph from the Middle Triassic Denwa Formation, Satpura Gondwana Basin, India.

This report describes two adjacent, longitudinally-fused anterior cervical vertebrae from a basal archosauromorph. The specimen was collected from the Denwa Formation, Satpura Gondwana Basin, India. The differential diagnosis of the fusion includes genetic or environmentally-mediated congenital malformations, nonspecific spondyloarthopathy, and various infectious agents. These observations represent the first published recognition of archosauromorph vertebral pathology from specimens that were discovered in India. The observations affirm that basal archosauromorphs suffered from disorders that have been observed in later dinosaurs and modern-day vertebrates. Considering the process of orderly differential diagnosis is an important aspect of understanding lesions of ancient bones.

Congenital ocular and adnexal disorders in reptiles.

Ocular and adnexal congenital disorders are those that manifest at birth and could involve single or multiple tissues. Several abnormalities have been reported in literature affecting reptilian ocular and/or adnexal tissues. The objectives of this review are: (i) review those disorders previously reported in reptile literature; (ii) present new cases; (iii) provide a basic classification of them according to the moment of occurrence and (iv) indirectly, encourage the clinician dealing with these cases to go further in their diagnosis. The authors consider that categorizing ocular and adnexal congenital disorders could help the clinician to deal with them. The categorization of these disorders required an intense review of cases previously reported in literature and allows the authors suspect that some of them could not have been accurately diagnosed according to the definitions of the anomalies and/or not accurately described. The authors consider that ocular and adnexal congenital disorders could have been underestimated in reptiles and further studies could be helpful to promote the description of new disorders and to expand the knowledge about those previously reported. The review will first describe abnormalities reported during organogenesis (describing possible etiopathogenesis, cases reported, an approach to their diagnosis and recommended therapeutic options).Then a mention of the ocular disorders occurring after organogenesis is made. These disorders are divided when possible in those affecting all or most part of the globe and those affecting only specific tissues (surface ectoderm, neurocrest and mesenchyma and neuroectoderm).

A two-headed reptile from the Cretaceous of China.

A malformed embryonic or neonate choristoderan reptile from the Lower Cretaceous Yixian Formation of northeastern China is described. The tiny skeleton exhibits two heads and two necks, with bifurcation at the level of the pectoral girdle. In a fossil, this is the first occurrence of the malformation known as axial bifurcation, which is well known in living reptiles.

Variações anatômicas no aparelho reprodutor masculino de Chaunus ornatus (Wied-Neuwied, 1821) (Anura, Bufonidae) / Anatomical variations in the male reproductive system of Chaunus ornatus (Wied-Neuwied, 1821) (Anura, Bufonidae)

Este trabalho descreve variações morfológicas nos órgãos e estruturas do aparelho reprodutor masculino em Chaunus ornatus, analisados independentemente das alterações promotoras de variações estruturais. Foram utilizados sete exemplares adultos da espécie, coletados no Município de Botucatu (São Paulo, Brazil) na época de atividade reprodutiva. Os espécimes foram dissecados e medidas do comprimento rostro-cloacal, análises anatômicas descritivas e biométricas foram obtidas. Três destes animais foram encaminhados à rotina histológica para a análise da arquitetura testicular e esquematizada em papel vegetal com caneta nanquim. Análises estatísticas (média, desvio-padrão, teste de Shapiro-Wilk, teste t de Student e Regressão Linear Simples) foram empregadas para interpretação dos resultados. Os testículos de C. ornatus são cilíndricos com coloração branco-leitosa e possuem uma estrutura ovariana rudimentar, o órgão de Bidder, em sintopia com a extremidade testicular cranial. O aparelho reprodutor masculino de C. ornatus apresenta conspícuas variações anatômicas intra e interindividuais, especialmente no que concerne à forma e tamanho dos testículos e dos órgãos de Bidder, os quais não apresentaram relação com o tamanho do indivíduo. Quanto à localização, os testículos dispõem-se ventralmente aos rins, mas ocorrem em alturas diferentes, acompanhando diferenças atribuídas à própria posição dos rins. Nos corpos adiposos abdominais, a disposição e número de prolongamentos que o constitui é variável entre os membros do par, e conseqüentemente entre indivíduos. Histologicamente não foram observadas diferenças quanto ao arranjo do epitélio germinativo na constituição do lóculo seminífero, portanto estas características parecem seguir o padrão da descrição para os demais anuros. A heterogeneidade morfológica quanto às variações anatômicas nessa espécie teve uma constatação pouco significativa. Assim, outros estudos ainda são necessários para o...

This work describes morphologic variations in the organs and structures of the male reproductive system in Chaunus ornatus, analyzed independently from the alterations that promote structural variations. Seven adult samples were used, they were collected in Botucatu (São Paulo State, Brazil) during reproductive activity period. The specimens were dissected and rostrum-cloacal length measures were taken. Descriptive and biometrics anatomical analyses were also obtained. Three of these animals were sent to histological routine for the analysis of the testicular architecture, where it was schematized in vegetable paper with pen Indian ink. Statistical analyses (mean, standart deviation, Shapiro-Wilk test, Student's t and Simple Lineal Regression) were used for interpretation of the results. The testes of C. ornatus are cylindrical with white coloration and they possess a rudimentary ovarian structure, the Bidder's organ, in the testicular cranial extremity. The male reproductive system of C. ornatus presents conspicuous anatomical variations intra and interindividuals, especially to the form and size of the testes and of the Bidder's organ, which did not present relationship with the size of individual. As for the location, the testes are disposed ventral to the kidneys, but they are in different levels, accompanying differences attributed to the kidneys levels. The disposition and number of extensions in the abdominal fatty bodies is variable among the pair's members, and consequently among individuals. Histologically differences regarding the germ epithelium arrangement were not observed. The germ epithelium is arranged in seminiferous locule, therefore these characteristics seem to follow the pattern of the description for the other anurans. The morphologic heterogeneity for anatomical variations in that species were few significant. Thus, other studies are still necessary for the establishment of morphologic relations and its phylogenetic...