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Systematics of Neotropical gastropod-eating snakes: the dimidiata group of the genus Sibon, with comments on the nebulata group
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Sibon dimidiata and S. sanniola comprise the dimidiata group of Sibon, and S. nebulata and S. dunni the nebulata group. The species within each group are more closely related to each other than to any other species of Sibon. S. annulata, S. argus and S. longifrenis are placed in the synonymy of S. dimidiata, with no basis for recognition of the nominal subspecies S. dimidiata grandoculis. S. sanniola has two subspecies, the nominate form and S. sanniola neilli. The dimidiata group is distinguished by the shared characteristics of: (1) non-cylindrical body (laterally compressed or bread-loaf shape in cross section); (2) head distinctly wider than neck; (3) protruding eyes of large diameter; (4) vertebral and paravertebral scales not or only scarcely wider than other dorsals; (5) 11-20 maxillary teeth; (6) 20-27 dentary teeth; and (7) 1 or 2 postmental scales. The nebulata group is distinguished by the shared characteristics of: (1) laterally compressed body; (2) head distinctly wider than neck; (3) vertebral scales 1 1/4 -1 1/2 times wider than other dorsals; (4) about 12-17 maxillary teeth; (5) about 18-24 dentary teeth; and (6) absence of a postmental scale.
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Bidder's organs: Bufonid by-products of the evolutionary loss of hyperfecundity
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Bidder's organs in both male and female bufonids are hypothesized to represent a transitory state in an evolutionary transformation from extensive, hyperfecund ovaries to smaller, less fecund ones-a transformation that other families of anurans experienced in forms now long extinct. Some members of the genus Bufo retain considerable hyperfecundity, but in derived species of Bufo and genera of Bufonidae a spectrum of ovarian reduction exists. In those groups, Bidder's organs normally persist, always in males and often in females, as an undifferentiated ovaroid or ovary in a non-functional transition between the ancestral state and modification as part of the fat body. The organs are gynomorphs in males and highly variable as vestigial structures, but may well have endocrinogenic functions in both sexes although gametogenic functions in nature have been lost in males. Presence of Bidder's organs is a derived condition in the context of anurans as a whole, but primitive within the family Bufonidae.
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Disponibilidad y uso de recursos tróficos por Lacerta schreiberi y Podarcis bocagei en simpatría en una localidad de la Cordillera Cantábrica, España
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Food availability and diet composition were examined in sympatric populations of Lacerta schreiberi and Podarcis bocagei at a locality in the Cantabrian mountains (province of León, Spain). Neither species uses trophic resources in proportion to their relative abundance. Extensive overlap in diet composition has been found between P. bocagei and juvenile L. schreiberi. Although both species feed mainly on spiders, juvenile L. schreiberi eat the most abundant and P. bocagei select larger prey sizes. Subadult and adult L. schreiberi select beetles and grasshoppers.
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Non-random mating by size in the midwife toad Alytes obstetricans: Bigger males carry more eggs
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The European midwife toad Alytes obstetricans is unusual because the males exhibit parental care. The male carries eggs (possibly from several females) wrapped around his hind limbs until they are ready to hatch. The mating pattern of this species is not random; a significant correlation was found between male snout-vent length and dorsal egg count. Bigger males have larger broods and therefore father more offspring. Because brood size does not appear to affect egg hatching success, larger males may enjoy higher fitness. This non-random pattern of mating may be achieved by male intra-sexual competition, and both male and female mate choice.
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Amphibien als Transporteure limnischer Muschelkrebse: Ein Parameter zur Analyse der Verteilung von Bombina variegata 1
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Phoresis of the ostracod species Cyclocypris ovum on yellow-bellied toads (Bombina variegata) was studied in an area of temporary pools in northeastern Austria. Based on the assumption that infested toads have been staying in areas of high ostracod abundance, the high percentage of toads with attached ostracods (18.9%) made it possible to use the phenomenon to analyse the dispersal of toads to aquatic sites. Males had a significantly higher attachment rate. A lower percentage infestation of paired toads (9.3 %) could be interpreted as due to change in microhabitat during breeding activity. The highest rate of infestation was registered for males at high levels in the pools, showing that males have a tendency to crowd at peripheral areas of shallow water.
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Is there a direct link between the ophidian tongue and Jacobson's organ?
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An analysis of the interaction between the tongue and Jacobson's organ was conducted using x-ray cinematography and two experimental procedures. The results failed to support the traditional hypothesis of a direct linkage between the tongue and Jacobson's organ since the tongue was never observed to enter the lumen of Jacobson's organ. Conversely, the results presented provide strong support for the role of elevation of the anterior lingual processes as the mechanism for stimulus transfer.
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Reproduction of yellow-bellied toads Bombina variegata in a man-made habitat
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A breeding population of Bombina variegata-a prolonged breeder, spawning predominantly in temporary pools-was studied in a Swiss gravel-pit in 1985. During the study, the number of pools and ponds varied from 10 to 23, as a result of drought and exploitation. No significant loss of tadpoles because of pool drying was found. Spawning was observed from 6 May to 9 August. No distinct calling or spawning periods were found, although the activities varied markedly among breeding pools. There was a turnover in males and females during the whole breeding season. Mate choice was not size-selective, and in several pools there was no correlation between calling and mating. The results contrast with observations in other Bombina variegata populations. It is concluded that in populations living in artificial habitats, essential behavioral adaptations to a temporary environment may not be expressed.
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Vipera albizona, a new mountain viper from central Turkey, with comments on isolating effects of the Anatolian "Diagonal"
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The Anatolian "Diagonal" divides Turkish Anatolia into two major zoo- and phytogeographical regions. Along this "Diagonal" a series of closely related species of vipers are distributed: Vipera bornmuelleri, Vipera bulgardaghica, and Vipera wagneri. To this series a new species, Vipera albazona sp. n. is added. The importance of this "Diagonal" as a mechanism for dispersal and speciation is also discussed.
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Field body temperatures of the lizard Anguis fragilis
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The presence of a Musculus Retractor Cloacae in female caecilians (Amphibia: Gymnophiona)
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On hibernation sites in the tree frog Hyla arborea
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SEH News
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