Extreme tadpoles: the morphology of the fossorial megophryid larva, Leptobrachella mjobergi

The bizarre larvae of Leptobrachella mjobergi are fossorial and live in the gravel beds of small streams. These tadpoles are vermiform in body shape. Here we present details on their skeleton and musculature, particularly of the head. The entire cranium and its associated musculature are reconstructed in three dimensions from serial histological sections. The hyobranchial apparatus is highly reduced. The head of the L. mjobergi larva is more mobile than in other anuran species. This mobility can largely be ascribed to the exclusion of the notochord from the cranial base and an articulation of the foramen magnum floor with the atlas of the tadpole. The articulation is unique among anuran species, but design parallels can be drawn to salamanders and the articulation between atlas and axis in mammals. In L. mjobergi , the atlas forms an anterior dens that articulates with the basal plate in an accessory, third occipital articular face. The muscle arrangements deviate from the patterns found in other tadpoles: For instance, epaxial and ventral trunk muscles reach far forward onto the skull. The post-cranial skeleton of L. mjobergi is considerably longer than that of other anurans: it comprises a total of 35 vertebrae, including more than 20 post-sacral perichordal centra. Despite a number of features in cranial and axial morphology of L. mjobergi , which appear to be adaptations to its fossorial mode of life, the species clearly shares other features with its megophryid and pelobatid relatives. r 2005 Elsevier GmbH. All rights reserve

Red Hot Chili Pepper. A New Calluella Stoliczka, 1872 (Lissamphibia: Anura: Microhylidae) from Sarawak, East Malaysia (Borneo)

A new brightly-coloured (olive and red) species of microhylid frog of the genus Calluella Stoliczka 1872 is described from the upper elevations of Gunung Penrissen and the Matang Range, Sarawak, East Malaysia (Borneo). Calluella capsa, new species, is diagnosable in showing the following combination of characters: SVL up to 36.0 mm; dorsum weakly granular; a faint dermal fold across forehead; toe tips obtuse; webbing on toes basal; lateral fringes on toes present; outer metatarsal tubercle present; and dorsum greyish-olive, with red spots; half of venter bright red, the rest with large white and dark areas. The new species is the eighth species of Calluella to be described, and the fourth known from Borneo. A preliminary phylogeny of Calluella and its relatives is presented, and the new taxon compared with congeners from Malaysia and other parts of south-east Asia

From a lost world: an integrative phylogenetic analysis of Ansonia Stoliczka, 1870 (Lissamphibia: Anura: Bufonidae), with the description of a new species

While the island of Borneo is considered a global biodiversity hotspot, the species richness in many groups remains unknown and appears underestimated. During herpetological surveys carried out in the interior of Sarawak, East Malaysia, several individuals of a small species of the genus Ansonia Stoliczka 1870 were collected on the Usun Apau plateau and in the Gunung Hose mountain range (Ansonia sp. Usun Apau). An integrative taxonomic approach comprising phylogenetic (2.4 kb mitochondrial rDNA fragment, Bayesian Inference and Maximum Likelihood, >5.1 % to its closest relative) and morphometric analyses (25 measurements, multivariate ratio analysis and linear discriminant analysis), as well as morphological comparisons support the status of this operational taxonomic unit as a separate taxon at species level. The obtained phylogenetic hypothesis corroborates the two major clades within Ansonia found in previous studies. Within Clade One Ansonia sp. Usun Apau and the enigmatic Ansonia torrentis are part of a monophyletic group of the Bornean species Ansonia hanitschi, Ansonia minuta, Ansonia platysoma, Ansonia spinulifer, Ansonia vidua, and two additional undescribed taxa. This subclade must be considered as the result of an on-island radiation in the complex evolution of Ansonia. The new species is formally described including the identification of diagnostic morphometric traits. Ansonia sp. Usun Apau is endemic to two isolated mountain ridges in central Sarawak and must be considered as a new element of the unique diversity of the Bornean amphibian fauna that is potentially threatened by habitat loss at least in parts of its range

The anatomy and structural connectivity of the abdominal sucker in the tadpoles of Huia cavitympanum, with comparisons to Meristogenys jerboa (Lissamphibia: Anura: Ranidae)

The tadpoles of many anuran amphibians inhabit lotic habitats and evolved oral devices to adhere to the substratum. Although published anatomical descriptions of rheophilous tadpoles exist, little is known about the modifications in gastromyzophorous tadpoles that possess abdominal suckers and live in torrential sections of streams. We describe the gastromyzophorous tadpoles of Huia cavitympanum and Meristogenys jerboa from torrential streams of Borneo, with special attention to the anatomy of their abdominal suckers and their relations to cranial structures and musculature. One cranium of H. cavitympanum and its associated muscles were computer-reconstructed in three dimensions from serial histological sections. The abdominal sucker and oral sucker comprise a set of muscles and ligaments that attach to internal skeletal structures. Some muscles could be identified to attach directly to soft tissue of the abdominal sucker and most likely contribute to suction. Comparing tadpoles of H. cavitympanum to the closely related gastromyzophorous M. jerboa reveals differences in external and internal features, such as cornu trabeculae fusion and jaw details. Because of phylogenetic uncertainties, it is unclear whether or not this structural complex evolved once or several times convergently in ranids