159
Meyer, E., Jamieson, B.G.M. and
Scheltinga, D.M.
1997f. Sperm ultrastructure of six Australian hylid frogs from two
genera (Litoria and Cyclorana): phylogenetic
implications. Journal of Submicroscopic Cytology and Pathology
29, 443-451.
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. AR 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.
novaehollandiaeand 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.