The Herpetological Journal

pp.137-146 

Authors: Roger Meek

Abstract: Observations were made on the thermoregulatory behaviour and activity patterns of Physignathus cocincinus in a simulated tropical environment. P. cocincinus is a sit-and-wait predator with movement restricted to a maximum of 9 or 10 bursts of activity per day. Both terrestrial and aquatic activity were temperature dependent, and were greatest in hot, sunny weather. When the weather was overcast, the lizards spent most of their time in open areas and at higher levels in the canopy; increased sunshine induced movement to lower levels, with more time spent in shade. Regression analysis of the relationship between lizard and model temperatures was used to determine thermoregulation. P. cocincinus is basically a thermoconformer, but needs to thermoregulate on sunny days to avoid excessive heat loads. Control of body temperature during hot and intermittent sunshine was principally achieved by seeking shade and partial basking. On cloudy days the animals were thermoconformers, as environmental temperatures were sufficiently high to enable locomotory activity and feeding to take place, but not so high that excessive heat loads became a problem.

Keywords: Physignathus cocincinus, thermoregulation, activity patterns

pp.147-151

Authors: D. J. Harris, E. A. S!nclair , N. L. Mercader , J. C. Marshall And K. A. Crandall

Abstract: Relationships among squamate families have classically been difficult to establish, with morphological characters being interpreted to give many different topologies. Here we combine new C-mos nuclear DNA sequence data with those already published to assess relationships of 19 families within the Squamata. Monophyly of all the families examined is upheld. Many relationships between families are estimated, although it appears there may have been rapid cladogenesis associated with the origins of the Squamata.

Keywords: Phylogeny, squamates, C-mos

pp.153-162

Authors: Peter Lenk And Wolfgang Wüster

Abstract: We used multivariate analysis to study patterns of geographic variation in morphology in the Aesculapian snake, Elaphe longissima, in Italy and other parts of its range, in order to evaluate the status of the southern Italian form, hitherto known as E. I. romana. Although that taxon was previously regarded as weakly differentiated, a recent study based on blood proteins showed a high level of differentiation, similar to that observed between full species of European Elaphe . Fourteen characters relating to external morphology were recorded from 104 adult specimens of Elaphe longissima from 52 localities, and subjected to multivariate analysis. The results show that southern Italian specimens are clearly distinct from those of other populations. The morphological divergence is coupled with a parapatric distribution pattern and a sharp transition at the contact zone in central Italy. We found the distribution limits of the two taxa to be situated about 100 km further south than previously suggested. Parapatry among morphologically clearly distinct forms, and differences in blood plasma suggesting considerable evolutionary divergence, provide reasons for considering the southern Italian form as a separate evolutionary species from E. longissima. The name Coluber romanus Suckow, 1798 is not available for the southern Italian species, for which the oldest available name is Callopeltis longissimus var. lineata Camerano, 1891, in the combination Elaphe lineata.

Keywords: Elaphe, multivariate analysis, taxonomy, morphology, zoogeography

pp.163-167

Authors: Sebastiano Salvidio , Roberto Sindaco And Livio Emanueli

Abstract: The diets of three Corsican amphibians, Discoglossus montalentii, Discoglossus sardus and Euproctus montanus, were studied in the Ospedale region during the breeding season. Adult specimens were collected in or around breeding pools and were stomach flushed in the field. Prey taxa included a large variety of terrestrial and aquatic prey items of variable size, indicating opportunistic predation. All species were able to catch their prey both on land and in water, but varied in the proportions of aquatic and terrestrial prey consumed. E. montanus fed largely upon benthic macroinvertebrates, suggesting predation in deep water; D. sardus mainly captured terrestrial prey; and D. montalentii showed a mixed feeding strategy, preying upon both terrestrial and aquatic prey categories in similar proportions. Discoglossus sardus showed the highest standardized value of niche breadth (D, = 0.769), compared to D. montalentii and E. montanus (D, = 0.544 and D, = 0.523 respectively). When prey size frequency distributions were compared, no specific differences were observed. These results indicated that, at least during the breeding season, trophic segregation among sympatric amphibians was maintained by different foraging strategies, and that the three species exploited contiguous microhabitats in different ways.

Keywords: Corsica, Discoglossus, Euproctus, foraging strategy, sympatry

pp.169-177

Authors: David N .Tarkhni Shvili And Ramaz Gokhelashvili

Abstract: A spatially structured population of the brown frog Rana macrocnemis was studied over seven consecutive years in the valley of a small mountain river. Frogs spawned in numerous temporary pools and puddles situated along the river bed. The overall number of reproductive females varied between 868 and 1146 during the course of study. The population had a 'sourcesink' spatial structure: 88% of all froglets metamorphosed in just a few of the sites. Density dependent mortality of larvae did not significantly affect the overall number of metamorphs. However, the variation in size of the whole population and of one of the two sub-populations was density-dependent. The most important cause of regulation appears to be density-dependent dispersal of juveniles from sources to adjacent sinks. Sinks often had a high number of ' traps' - large well-illuminated pools that frogs prefer for egg deposition but which desiccate during the course of larval development more often than the deep and cold, less attractive breeding sites.

Keywords: Rana macrocnemis, frog populations, spatial ecology