It has been noted that caudal autotomy as a way of defending against predators in recent reptiles is characteristic solely of lepidosaurs and is absent in crocodiles and turtles. It was found that, in the order Rhynchocephalia and in representatives of the majority of families of lizards, intravertebral (IntraVB) autotomy is a widespread phenomenon, whereas agamid lizards and some snakes do not have a break plane, and their tails break between adjacent vertebrae (intervertebral (InterVB) autotomy). The frequencies of occurrence of InterVB autotomy and regeneration in six species of agamas of the genus Paralaudakia were analyzed. Six types of regenerate’s characteristic of the studied group and the anatomical structure of the knob -shaped jagged regenerate are described on the basis of the results of computed microtomography (micro-CT). Phenomena of autotomy and regeneration are discussed in the phylogenetic context.

The North American terrapin, the red-eared slider, has globally recognized invasive status. We built a new extensive database using our own original and literature data on the ecology of this reptile, representing information on 1477 water bodies throughout Eurasia over the last 50 years. The analysis reveals regions of earliest introductions and long-term spatio-temporal dynamics of the expansion covering now 68 Eurasian countries, including eight countries reported here for the first time. We established also long-term trends in terms of numbers of terrapins per aquatic site, habitat occupation, and reproduction success. Our investigation has revealed differences in the ecology of the red-eared slider in different parts of Eurasia. The most prominent expression of diverse signs of invasion success (higher portion of inhabited natural water bodies, higher number of individuals per water body, successful overwintering, occurrence of juvenile individuals, successful reproduction, and establishment of populations) are typical for Europe, West Asia and East Asia and tend to be restricted to coastal regions and islands. Reproduction records coincide well with the predicted potential range based on climatic requirements but records of successful wintering have a wider distribution. This invader provides an excellent and possibly unique (among animals) example of wide alien distribution, without the establishment of reproducing populations, but through the recruitment of new individuals to rising pseudopopulations due to additional releases. Therefore, alongside the potential reproduction range, a cost-effective strategy for population control must take in account the geographical area of successful wintering.

We present a review of the data on the intervertebral autotomy and regeneration of agamid lizards based on an analysis of information obtained over a 35-year period after the publication of thorough reviews (Arnold, 1984, 1988 and Bellairs, Bryant, 1985). It is supplemented by our own studies of 869 specimens of agamid lizards (Sauria, Agamidae) stored in the herpetological collections of the Zoological Institute of the Russian Academy of Sciences (St. Petersburg, Russia) and the Zoological Museum of the Moscow State University (Moscow, Russia), represented by 31 species of 16 genera. The manifestations of the ability for autotomy and regeneration in phylogenetic lineages within the family—Leiolepidinae, Amphibolurinae, Agaminae, Draconinae—are considered. A comparative morphological analysis of the structure of the caudal vertebrae was carried out using the Computer Microtomography Methods (micro-CT) in the following ecomorphological types of agama: (1) with developed abilities to caudal autotomy and regeneration, (2) with the ability to caudal autotomy but without regeneration and (3) without the ability to autotomy. The phenomenon of intervertebral autotomy (urotomy) in snakes is considered too. Possible ways of evolution of the ability to caudal autotomy as a defense strategy against predators are discussed in the phylogenetic context.

Osteoderms are bony structures that develop within the dermal layer of the skin in vertebrates and are very often found in different lizard families. Lizard osteoderms are diverse in topography, morphology, and microstructure. Of particular interest are the compound osteoderms of skinks, which are a complex of several bone elements known as osteodermites. We present new data on the development and regeneration of compound osteoderms based on the results of a histological and Computed Microtomography (micro-CT) study of a scincid lizard: Eurylepis taeniolata. The specimens studied are stored in the herpetological collections of the Saint-Petersburg State University and Zoological Institute of the Russian Academy of Sciences located in St. Petersburg, Russia. The topography of osteoderms in the integuments of the original tail area and its regenerated part was studied. A comparative histological description of the original and regenerated osteoderms of Eurylepis taeniolata is presented for the first time. The first description of the development of compound osteoderm microstructure in the process of caudal regeneration is also presented.

Изучены распространение и типы популяционных систем зеленых лягушек (Pelophylax esculentus complex) на северо-западе Волгоградской области. Методом проточной ядерной ДНКцитометрии установлено обитание прудовой лягушки (P. lessonae) в двух пунктах, что позволило сдвинуть известную ранее южную границу ареала вида на 30 км. Более того, новые находки, с зоогеографической точки зрения, выводят распространение вида из пределов лесостепной зоны в зону степей. Выявлены два типа популяционных систем: а) R-тип, или «чистые» популяции P. ridibundus; и б) R-L-тип, т. е. смешанная популяционная система, включающая P. ridibundus и P. lessonae. Гибридогенная P. esculentus не обнаружена. Библиогр. 12 назв. Ил. 1. Табл. 1.

Currently, more than 58 skeletal anomalies and pathologies are known in the recent Squamata reptiles. In this paper, eight pathologies of a complex nature are described in Agamidae and Lacertidae: Paralaudakia caucasia (Eichwald, 1831) and Lacerta agilis Linnaeus, 1758. Description of tail pathologies was carried out based on the analysis of X-ray images and on the results of computer microtomography. In the specimen of P. caucasia (ЗИН 19116.1) complete ablation of the caudal vertebra was revealed, which provoked the detachment of chevron and the proliferation of soft tissues. In some Agamidae, after pseudoautotomy, partial ablation of the caudal vertebra occurs to promote wound healing. Complete ablation of the distal caudal vertebra has not been previously reported in literature. In females of L. agilis, deformation of the right transverse process of the vertebra with “false bifurcation” without the formation of a cartilaginous tube (VOLSU 98.2), scoliosis, hematoma and callus on the cartilaginous tube were noted, as well as the absence of an autotomy plane in the postpygal vertebra (ZIN 31549). An unusual pathology in L. agilis (ZIN 31549) is the absence of an autotomy plane in the postpigal vertebra and of its anterior neural spine. The loss of the plane of autotomy during ontogeny is characteristic of some Iguanidae, but it has not been previously noted in Lacertidae. The described cases of anomalies expand the spectrum of known pathologies in reptiles.