BACKGROUND The present-day amphibian and reptile fauna of Western Siberia are the least diverse of the Palaearctic Realm, as a consequence of the unfavourable climatic conditions that predominate in this region. The origin and emergence of these herpetofaunal groups are poorly understood. Aside from the better-explored European Neogene localities yielding amphibian and reptile fossil remains, t...

Herpetological Review has recently featured a series of papers debating the merits of recent developments in the theory and practice of systematic biology, using herpetological examples. In the latest and longest paper in this series, Pritchard (1994) passionately argued against many of these "cladistic" developments. Here I address three issues raised in his paper that bear directly on my own ...

Plasmodium kentropyxi n.sp. is described in the teiid lizard Kentropyx calcarata from north Brazil. Young asexual stages and gametocytes are at first polar in the erythrocyte but with elongation, move to a lateral position. Largest meronts seen contained from 30-40 nuclei and conspicuous greenish-black pigment granules located in a distinct vacuole. With growth the gametocytes eventually assume...

Eimeria carmelinoi n.sp., is described in the teiid lizard Kentropyx calcarata Spix, 1825 from north Brazil. Oocysts subspherical to spherical, averaging 21.25 x 20.15 micro m. Oocyst wall smooth, colourless and devoid of striae or micropyle. No polar body or conspicuous oocystic residuum, but frequently a small number of fine granules in Brownian movement. Sporocysts, averaging 10.1 x 9 microm...

Macroscopic and histological analyses of the ovarian cycle of Crotaphytus col/aris were conducted during 1971 and 1972. The reproductive season extends from April to late June; examination of ovarian h istosections revealed two distinct sets of corpora lutea, indicating that two clutches of eggs are produced per season. The average clutch size was 6.4. Corpora lutea regress into permanent ovari...