Cyclorana

Abstract: The spermatozoa of four fossorial (Litoria alboguttata, Cyclorana brevipes, Cyclorana novaehollandiae and Cyclorana cryptotis) and two non-fossorial australian hylid frogs (Litoria aurea and Litoria moorei) together with previously examined Litoria (Hylidae: Anura) are compared In spermatozoal ultrastructure (in particular the structure of the sperm tail) Cyclorana includes species which appear derived (apomorphic) relative to non-fossorial species of Litoria while the fossorial L alboguttata groups with Cyclorana All hylid species examined here are united by the bufonoid synapomorphy of a conical subacrosomal cone consisting of separate sheaves and the eubufonoid synapomorphy of a mitochondrial sheath or collar separated by a cytoplasmic canal from the centriolar region and tail Spermatozoal symplesiomorphies for the Eubufonoidea, seen in Litoria (with the exception of L alboguttata), are the well developed thin undulating membrane with juxta-axonemal and axial fibre L alboguttata, C novaehollandiae and C brevipes appear monophyletic in the apomorphic modification of the undulating membrane as a thick, dense structure In L alboguttata and C novaehollandiae this structure retains a swelling, at the free edge, homologized with the axial rod C brevipes has a further apomorphy as the undulating membrane forms a parallel-sided dense structure with no separate differentiation of an axial fibre C cryptotis, however, retains the plesiomorphic sperm tail with a thin undulating membrane, juxta-axonemal and axial fibre That these differences in spermatozoal ultrastructure have phylogenetic significance is endorsed by the similarity of the fertilization biology of the species examined On the basis of sperm ultrastructure three separate lineages are discerned within Cyclorana s lat: 1) C cryptotis; 2) L alboguttata and C novaehollandiae; and 3) C brevipes The evidence of sperm ultrastructure, supported by previously published molecular, morphological and karyological data, clearly places Litoria alboguttata within the genus Cyclorana

Abstract: Serum albumins were compared in 17 species of Australian frogs by the quantitative micro-complement fixation technique. On the basis of albumin comparisons, all species of Cyclorana studied are phylogenetically closer to the L. aurea species-group than are other non-L. aurea group Litoria. Additionally, L. alboguttata is genetically closer to Cyclorana australis than any other frog tested (except for C. novaehollandiae) and clusters with the Cyclorana species, not with Litoria. By use of albumin as a molecular clock, it is estimated that the lineage leading to Cyclorana and the L. aurea species-group diverged in the Late Eocene from lineages leading to other Litoria. The lineages leading to the L. aurea group and to Cyclorana separated in the Oligocene. Eastern and western members of the L. aurea group diverged from each other in the Early Pliocene to Late Miocene, and not in the Pleistocene as is generally presumed.

Abstract: The outcomes of host-parasite interactions depend heavily on the host's immune response, which, in turn, is governed by previous interactions between the host and parasite, both over the host's life time and over evolutionary time. In the case of species introductions, such as the cane toad (Bufo marinus) to Australia, parasites that are benign to native species of the introduced range may present a major challenge to the introduced species. Stomachs of introduced cane toads and seven species of sympatric native frogs were examined for parasites, and their pathology and biology were compared. Cane toads were host to eight species of third-stage spirurid larvae, six of which also occurred in the stomach wall of four native frog species. In general, encysted nematode larvae attained higher prevalence and species richness in introduced cane toads than in sympatric native frogs. This trend was largely explained by differences in body sizes: larger anurans were more likely to possess infections, and cane toads are inherently larger than native frogs. Encysted larvae in cane toad stomachs provoked a marked pathologic response. All larvae (physalopterine and Physocephalus spp.) were surrounded by concentric layers of dense, fibrous tissue, with considerable cellular infiltration characterized by lymphocytes and polymorphs. Many cysts were invaded by cells and exudate, which, in more advanced cases, became calcified. Some larvae appeared viable; most were in various stages of destruction, and some smaller Physocephalus spp. were mummified. Conversely, pathologic response observed in native frogs was minimal, with little fibrotic reaction surrounding the cysts, and no cellular infiltration. Presumably, the contrast in pathology between introduced and native hosts reflects the long evolutionary association between these nematode larvae and native frogs, whereas the recent exposure of introduced toads to these helminths provokes a severe reaction.