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The Laticauda colubrina complex previously consisted of three species, Laticauda saintgironsi from New Caledonia and the Loyalty Islands, Laticauda frontalis from Vanuatu, and Laticauda colubrina, a widespread species ranging from the Andaman and Nicobar Islands and the Myanmar-Thai-Malaysian peninsula, through the Indonesian archipelago to New Guinea, north to Palau, the Philippines, Taiwan and the Ryukyu Islands, and southeastward along the island-chain of the Solomon Islands, Vanuatu, Fiji and Tonga. Their geographic variation, based on 1515 specimens involving 33 characters of coloration and scutellation, was analyzed in two different ways: (1) an hierarchical analysis and (2) an analysis of principal components and discriminant function. Sexual dimorphism occurred in many characters and for those, females and males were analyzed separately.
The results confirmed the distinctiveness of the three original species. Within L. colubrina different characters displayed slightly different geographic patterns of variation, but overall five general groupings of populations could be discerned: (1) a north-south axis from Sabah, north through the Philippines to Taiwan and the Ryukyus, (2) an east-west axis encompassing localities from the Andaman and Nicobar Islands in the west through New Guinea and the Solomon Islands in the east, (3) the eastern islands of Vanuatu, Fiji, and Tonga, (4) a partially isolated population in Palau, and finally (5) an isolate in southern Papua. Despite significant differences among these regions, different characters showed slightly different patterns of geographic variation across their boundaries; similarly, within each axis the pattern of variation among islands differed for different characters. Divergence was deemed sufficiently consistent to warrant taxonomic distinction only in the case of the population in southern Papua that was accorded recognition as a new species, Laticauda guineai. In some characters, widely peripheral populations were more similar morphologically to each other than to more central ones, and alternative hypotheses accounting for this are discussed.
The observed distribution and the geographic patterns of variation are attributable to a combination of present and past ecological restrictions, directions of sea currents, and paleogeography.
We studied the ecology of four species of closely related leaf litter geckos, Coleodactylus amazonicus, C. septentrionalis, Lepidoblepharis xanthostigma, and Pseudogonatodes guianensis in tropical rainforests of Brazil and Nicaragua. All are found in leaf litter of undisturbed tropical forest where mean hourly surface temperatures vary from 23.5–29.1 C. Surface temperatures, where individual C. amazonicus were found, averaged 27.4 C and air averaged 29.9 C. Coleodactylus amazonicus was the smallest species and L. xanthostigma was the largest. The latter was the most different morphologically as well. Tail loss rates varied from 45.5–81.8% among species. All four species ate very small prey items, largely springtails, homopterans, termites, small insect larvae, and spiders. Nevertheless, considerable differences existed among species. Some variation existed among populations of C. amazonicus. Prey size was correlated with lizard SVL within and among species. All four species are typically the smallest species in their respective lizard assemblages. Small body size may have consequences for predation. Partially due to small body size, these lizards are vulnerable to extirpation resulting from effects of tree removal on thermal attributes of their leaf litter environment.
Four new species of scincid lizards in the genus Lobulia are described from high elevations (≥2350 m) in New Guinea. Some of the features that may permit these skinks to live at high elevation are: dark color pattern, “tinted” lower eyelids and live-bearing reproductive mode. All of the species may be threatened by global climate warming. The generic concept of Lobulia is discussed and a key to the species provided.
Experimental studies of complex life cycles in plethodontid salamanders are reviewed and evaluated in the context of seven theoretical life-history models that focus on amphibians having biphasic life cycles. Such life cycles are found in the single species of the subfamily Hemidactylinae and in some members of the subfamily Spelerpinae and genus Desmognathus. In general, data on plethodontids provide only limited support for the predictions of the models. Given that the models have been formulated mainly for pond-breeding amphibians, several investigators have suggested that ancestral adaptation to streams in biphasic plethodontids have prescribed different evolutionary trajectories in the metamorphic response of these salamanders, in comparison with pond-breeding frogs and salamanders.
Larval and metamorphic characters tabulated for biphasic plethodontids show that there is considerable inter- and intraspecific variation in larval periods and sizes at metamorphosis. In all lineages, in most species, metamorphosis is concentrated in the late spring and summer. However, spelerpines and desmognathans differ markedly in the phenology of oviposition-nesting. Among spelerpine species, oviposition may occur in any season, whereas in desmognathans oviposition is usually restricted to late spring and summer. This represents another instance of life-history symmetry in desmognathans, and may reflect an effect of genetic and developmental constraints in this lineage.