Authors: R. C. Beattie, R. J. Aston And A. G. P. Milner

Abstract: Limestone was added to two acidic ponds in upland, northern England in an attempt to improve the survival of embryos and larvae of the common frog (Rana temporaria L.). As expected, the addition of limestone to the ponds resulted in a significant increase in both the pH and the dissolved calcium concentration of the pond water. Fertilization success of common frog eggs was approximately 87% in acidic water and increased to I 00% following liming. Embryonic survival in the two acidic ponds increased from 0% and 22% to 69% and 93% respectively following liming. A year after liming, embryonic survival in one pond had decreased significantly from 93% to 79%. It was estimated that at least 2. 1 % of the eggs deposited in a limed pond gave rise to metamorphs. The environmental implications of liming acidic frog breeding ponds are discussed.

Authors: J. R. Downie

Abstract: At 28°C, isolated Physalaemus pusrulosus eggs hatch after approximately 40 hours incubation. However. few tadpoles emerge from foam nests at this time. From nests incubated so that the foam remains moist. emergence occurs progressively over the next day. If the foam is allowed to dry on top, complete emergence takes even longer. Manipulation of the incubation environment shows that emergence is not stimulated by dark or light, nor does it occur at a particular time of day. Since hatching occurs at Gosner stage 21 and the last tadpoles to emerge from foam have reached Gosner stage 23-24, it is suggested that late emergence allows hatchlings to continue development to a more advanced stage in a protected environment: the foam acts as a post-hatching refuge. However, it is also shown that tadpoles emerging early are able to grow to Gosner stage 25 by the time the last tadpoles leave the nest: remaining in the nest therefore bears a cost. In addition. part of the delay in emergence may simply result from the time small tadpoles take to wriggle free from a large mass of cohesive foam.

Authors: Marcio Martins

Abstract: The reproductive behaviour of the Smith Frog, Hyla Jaber, was studied in an artificial permanent pond in southeastern Brazil. Males. built nests at the edges of this pond where eggs were laid. Reproductive activity continued from late October, 1988 through early March, 1989. Twenty five males and 20 females were marked at the pond. There was no sexual dimorphism in size and females did not choose the larger males. Mean male residency was 15.5 nights; only two females were observed for more than one night. Three different vocalizations were emitted during female attraction and courtship. Courtship behaviour was complex and nearly invariable. Male reproductive success varied between 1 -7 matings and was not correlated with male size, but was positively correlated with length of residency. Only one female was observed mating more than once. Except for minor details, the reproductive behaviour of the Smith Frog is very similar to that observed for Hyla rosenbergi, an ecologically and phylogenetically related species.

Authors: John Da Yenport And Colin R. Scott

Abstract: Twelve young green turtles (Chelonia mydas L. ) varied considerably in growth rate when fed satiation rations (mean specific growth rate ranged from 0.01045-0.0l462), but individual animals had constant specific growth rates. The following mean morphometric relationships were found: log y = -3.42 + 2.94 log x (where y = live weight (g) and x = carapace length mm)); log y = 0.069 + 0.93 log x (where y = carapace width (mm) and x = carapace length (mm)); log y = -0. 1 15 + 1 .01 log x (where y = plastron length (mm) and x = carapace length (mm)); log y = -0.417 + 2.04 log x (where y = plastron area (mm2) and x = plastron length (mm)). Growth was isometric throughout the period of study. There was no significant relationship between the allometric coefficients of the individual turtles and their specific growth rates or between carapace length/width ratios and specific growth rates. No turtle shape, or pattern of shape/weight change is associated with high or low rates of specific growth. The plastral scute patterns of green turtles are stable over time and are individually identifiable. Carapace scutes grow asymmetrically, with little posterior or medial growth, most scutal growth taking place anteriorly and laterally. Photocopying of the plastron and scute patterns as a growth/ identity technique was shown to be effective and inexpensive.

Authors: John Davenport And Colin R. Scott

Abstract: Mean appetite and oxygen uptake were highly variable amongst the 12 young green (Chelonia mydas L.) turtles studied. Neither appetite nor oxygen uptake had a statistically significant influence on specific growth rate. Amongst the efficiencies of assimilation of nutrients, there were quite wide individual variations in the rates of assimilation of energy, lipid and dry mass, but protein was assimilated with a uniformly high efficiency. Assimilation efficiencies of lipid and dry mass were significantly and positively correlated with specific growth rate. There were also strong positive correlations between the efficiencies of assimilation of different nutrients. There were weak negative correlations between appetite and the assimilation rates for energy and dry mass. These suggest that turtles compensate for a low efficiency of assimilation of these nutrients by an increased rate of food intake. Lipid assimilation in the turtles was lower than for the other nutrients. It was found that fatty acids are not all absorbed to the same extent. Saturated fatty acids and monounsaturated fatty acids were relatively poorly absorbed by comparison with polyunsaturated fatty acids.

Authors: Donald G. Broadley And Barry Hughes

Abstract: Variation in Lycophidion populations of the southern Sudan, Somalia, Ethiopia, Uganda and Kenya is analysed. Five species occur in this area: L. irroraturn and L. ornaturn are restricted to forests, L. depressirostre and L. taylori sp. nov. inhabit dry savannas, L. capense jacksoni is found in the moister savannas of the highlands and plateau areas, while L. capense loveridgei occurs in both forest and savanna of the coastal strip. L. irroraturn is readily distinguished by the paired apical pits on the dorsal scales. L. depressirostre and L. taylori both have lower ventral and subcaudal counts than the other taxa, but L. depressirostre can be distinguished from all other species by its more numerous maxillary teeth (8 to 9 + 19 to 24 compared with 7 to 8 + 11 to 1 8) and usually one colour pattern. L. taylori is very variable in colouration, but most specimens have a white blotch or collar on the nape and white dorsal stippling may be very extensive. The type series of L. taylori comes from the border between northern Somalia and Ethiopia, but there are isolated specimens from northern Kenya (Turkana District), Chad and Senegal.

Authors: J. Alan Holman

Abstract: The British Quaternary herpetofauna and the modern one are the products of adaptations to several disruptive patterns. These include mass habitat loss due to glaciation, alternating cold and temperate climates, and the development of seaways isolating the British Islands. Fossil herpetofaunas are now known from all of the Middle and Upper Pleistocene stages (except the Beestonian) and from the Flandrian. The cold stages have yielded only Rana temporaria, Lacerta vivipara and Natrix natrix. The temperate stages have been enriched by exotic continental species incuding: Pelobates fuscus, Pelodytes punctatus, Hyla sp., Rana arvalis, Rana esculenta or ridibunda, Rana lessonae, Emys orbicularis, Elaphe longissima, and Natrix maura or tessellata. Middle Pleistocene Cromerian Interglacial faunas collectively have 38.5% exotic species and Middle Pleistocene Hoxnian Interglacial faunas have 46.5% exotic species. Late Pleistocene Ipswichian (Last Interglacial) faunas have 45.5% exotic species. The only exotic species recorded from the Flandrian (Holocene) is Emys orbicularis. The modern British amphibian fauna must have been in place early in the Flandrian (Holocene), as five of the six modern species occur at the Whitemoor Channel Site, East Cheshire, 1 0,000 to 8,500 BP; and there seems no reason to doubt that the modern reptile fauna was also then in place