On Unique Forms of Anomalous Sacral Structure in Tailless Amphibians

E. E. Kovalenko, S. E. Danilevskaya


The unique structural anomalies of spinal column caused by unilateral development of pelvis are described in an adult specimen of Xenopus laevis and 2 larvae of Rana temporaria. In all the specimens the unilateral development of sacrum was observed. The described anomalies support the hypothesis of deforming influence of developing ilium on posteromost presacral segments as well as some assumptions on the factors determining the morphogenetic process in anurans.


Amphibia; Anura; sacral structure; variations; unique forms

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