Embryonic development of the monitor lizard, Varanus indicus

Abstract

Describing the stages of normal development ofVaranus indicus, the present paper provides the first developmental data on Varanidae. The incubation period is relatively long (180 days at 28°C) and without any diapause. The development is rather slow during the first 50 days, after which a considerable acceleration can be observed. The stage of accelerated growth terminates at app. 100 days when all essential specificities of adult organisation (prolonged narial region with vomeronasal organ, eyes, claws, large heart and robust body and limbs) are established. The remaining period of the embryonic development is characterized by continuation of the respective trends, i.e., enlarging body, prolongation of rostrum, enlarging teeth and claws, keratinisation of claws and scales etc. In short, the second half of the embryonic development ofVaranusis devoted to refining the structures supporting its adaptations for active predation.

Embryonic development of a parthenogenetic vertebrate, the mourning gecko (Lepidodactylus lugubris)

“…However, L. lugubris exhibit deviations from the other three gecko‐specific character states. Paired hemiphallic bulges of L. lugubris appear at stage 32, which is later than the gecko P. picta , the same timing as some pleurodonts, acrodonts, and gymnophthalmids, but earlier than anguimorphs, and later than other pleurodonts and lacertids . All three podial elements appear in the forelimbs at L. lugubris stage 32, which matches the timing of most geckos, gymnophthalmids, lacertids, some acrodonts, and anguimorphs, but is earlier than other acrodonts and pleurodonts, and later than other pleurodonts.…”

“…Paired hemiphallic bulges of L. lugubris appear at stage 32, which is later than the gecko P. picta, the same timing as some pleurodonts, acrodonts, and gymnophthalmids, but earlier than anguimorphs, and later than other pleurodonts and lacertids. 6,50,60,85,[87][88][89][90] All three podial elements appear in the forelimbs at L. lugubris stage 32, which matches the timing of most geckos, gymnophthalmids, lacertids, some acrodonts, and anguimorphs, but is earlier than other acrodonts and pleurodonts, and later than other pleurodonts. Finally, fusion of the facial primordia occurs at stage 33 which is the same timing as other geckos, some acrodonts, and anguimorphs, but earlier than lacertids, other acrodonts, and pleurodonts, and later than gymnophthalmids.…”

HNK‐1 in Morphological Study of Development of the Cardiac Conduction System in Selected Groups of Sauropsida

“…Serial sections of the C. niloticus embryos stained with HNK‐1 and hematoxylin from previous studies (Kundrat, ; Kundrat, ) were used for the crocodile model. Hearts of V. indicus were isolated from embryos originating in the collection assembled previously for the staging purposes (Gregorovicova et al, ). Hearts from the other species were extracted from the embryos submerged in a cold buffer optimized for reptiles (Jensen et al, ), or Tyrode's for the avian species ( G. gallus and C. japonica ) after rapid recording of their external appearance for documentation and staging purposes, fixed overnight in 4% paraformaldehyde solution in phosphate buffered saline (PBS) on ice with gentle rocking.…”

“…The material is derived from study by Kundrat (2008). Selected samples originating from a larger collection assembled by Gregorovicova et al (2012). and C. japonica) after rapid recording of their external appearance for documentation and staging purposes, fixed overnight in 4% paraformaldehyde solution in phosphate buffered saline (PBS) on ice with gentle rocking.…”

Bony skull development in the Argus monitor (Squamata, Varanidae, Varanus panoptes) with comments on developmental timing and adult anatomy

“…Studies on the development of Varanidae are, however, very scarce (Gregorovicova et al, 2012) and there is only a small amount of descriptive literature dealing with the skeletogenesis of the skull (Shrivastava, 1964a,b). The large body size and tropical distribution of varanids has made them less easy to obtain and maintain in laboratories.…”