The adrenal gland of Euproctus (Urodela, Salamandridae): comparison of three species and phylogenetic inferences.

Adrenal glands of three species of Euproctus (E. asper, E. montanus and E. platycephalus) were compared. Differences were observed as regards: (1) the distribution of the adrenal tissue, which is more sparse in E. asper than in the other two species; (2) the amount and size of the adrenal islets: in E. asper, they are numerous and small, in E. platycephalus, they are decreased in number and larger, in E. montanus they are few and very large; (3) the distance of the islets from the medial border of the kidney is variable in E. asper; in E. montanus they are mostly in contact with the medial edge, whereas in E. platycephalus they are distant from it. The adrenals of E. montanus and E. platycephalus are more similar to each other than to that of E. asper; the gland in this species may be considered a more primitive type. Such structural relationships are in agreement with phylogenetic inferences concerning the three species.