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Members of the snake subfamily Aparallactinae occur in various habitats throughout sub-Saharan Africa. The monophyly of aparallactine snakes is well established, but relationships within the subfamily are poorly known. We sampled 158 individuals from six of eight aparallactine genera in sub-Saharan Africa. We employed concatenated gene-tree analyses, divergence dating approaches, and ancestral-area reconstructions to infer phylogenies and biogeographic patterns with a multi-locus data set consisting of three mitochondrial (16S, cyt b, and ND4) and two nuclear genes (c-mos and RAG1). As a result, we uncover several cryptic lineages and elevate a lineage of Polemon to full species status. Diversification occurred predominantly during the Miocene, with a few speciation events occurring subsequently in the Pliocene and Pleistocene. Biogeographic analyses suggested that the Zambezian biogeographic region, comprising grasslands and woodlands, facilitated radiations, vicariance, and dispersal for many aparallactines. Moreover, the geographic distributions of many forest species were fragmented during xeric and cooler conditions, which likely led to diversification events. Biogeographic patterns of aparallactine snakes are consistent with previous studies of other sub-Saharan herpetofauna., (Copyright © 2018. Published by Elsevier Inc.)

Acrochordus is a species-poor but highly distinctive aquatic snake genus currently distributed from India to the western edge of the Pacific. We provide the first phylogeny for the three extant species using Bayesian and parsimony analyses of one mitochondrial and two nuclear gene sequences. Acrochordus javanicus is strongly recovered as sister to A. arafurae+A. granulatus, counter to expectations from superficial ecology, external phenotype and former taxonomy. We review and revise key fossil calibrations for dating snake divergences. Bayesian relaxed-clock analysis of the two nuclear loci yields deep interspecific divergences among extant species that occurred during the Miocene approximately 16 and approximately 20Mya (million years ago), pre-dating at least two of the three other living marine snake lineages. New morphological data for A. arafurae, and our molecular timescale, provide support for the placement of fossil taxon A. dehmi within the Acrochordus crown group, as sister to A. javanicus among nominate species. Finally, Acrochordus phylogeny provides an improved basis for taxon selection and character polarization in higher snake phylogenetics. Our study highlights the three Acrochordus species as old and highly distinct lineages that comprise an important component of the threatened Indo-Australian biodiversity., (Crown Copyright 2010. Published by Elsevier Inc. All rights reserved.)

The distributions of tyrosine hydroxylase (TH), protein gene product (PGP) 9.5, calcitonin gene-related peptide (CGRP), and peptide histidine isoleucine (PHI) have been examined immunohistochemically in the adrenal gland of the snake Waglerophis merremii. The morphology of chromaffin cells and the presence of ganglionic neurons in the gland revealed by means of the glutaraldehyde-silver technique and electron microscopy are also described. Two distinct types of TH-immunoreactive (-IR) cells are present in the dorsal noradrenergic ribbon: small chromaffin cells and a larger type identified as ganglionic neurons. Small, mostly round or fusiform cells often displayed long processes. Ganglionic cells, arranged in patches, had long processes entering the cortex of the gland. Chromaffin adrenergic cells, forming small groups of 4-7 cells, were scattered within the interrenal tissue and had a wide variety of shapes with processes that appeared to contact other chromaffin cells. Bundles of PGP 9.5-IR fibers occurred in the subcapsular zone of the adrenal gland with fibers entering the cortex and dorsal noradrenergic ribbon of the gland. Thick and thin TH-IR fibers were seen. Thick TH-IR fibers were nonvaricose and appeared to originate mainly in ganglionic neurons. Thin TH-IR fibers with small varicosities were numerous in the interrenal tissue and were frequently seen between clusters of adrenergic cells in close apposition to cortical cells and vessels. CGRP-IR fibers were present throughout the entire adrenal gland, whereas PHI-IR fibers had a preferential distribution in the interrenal tissue. Both CGRP- and PHI-IR fibers were closely associated with vessels and cortical cells.

The structure and function of the parathyroid glands of freshwater snake, Natrix piscator, were studied. N. piscator has two pairs of parathyroid glands which are composed of cell cords of typical endocrine appearance, and follicles are absent. Parathyroidectomy was followed by significant (P less than 0.001) hypocalcemia and hyperphosphatemia throughout the 5th week of experimental period. Following parathyroidectomy, calcium and phosphate concentrations in bone were significantly (P less than 0.05) increased after 5 weeks; however, these values in muscle were not significantly changed. Tetany was also observed in parathyroidectomized snakes. Histological structure and function of the glands do not appear to vary seasonally. Administration of parathyroid gland extract of this ophidian reptile into rats caused significant (P less than 0.05) elevation of serum calcium.

Eryx johnii and E. conicus possess two pairs of parathyroid glands (PTG) and one pair of ultimobranchial glands (UBG). The PTG is composed of cell cords and follicles, and is well vascularized. The presence of large vesicles with ciliated and glandular epithelium is the most striking feature of the PTG in E. johnii. Accessory PTG tissues are present. The unique feature of equal sized UBGs in Eryx is their location, i.e., bilaterally parallel and rostrally away from the thyrothymic region. The UBG is composed of follicles and cell aggregates, which are interspersed in a vascularized connective tissue stroma; ciliated and goblet cells are frequently present. The UBG of Eryx shows aging variation, but not seasonal changes; seasonal histological variations are observed in the PTG.