Lee, M.S.Y. and Jamieson, B.G.M. 1993a. The ultrastructure of the spermatozoa of bufonid and hylid frogs (Anura, Amphibia): implications for phylogeny and fertilization biology. Zoologica Scripta 22, 309-323.
Comparison of the spermatozoa of Bufo marinus, six Australian species of the family Hylidae, and the myobatrachine Adelotus brevis, with those of 41 other species of frogs, in a total of 12 investigated families allows the following phylogenetic inferences: the bufonoids (myobatrachids, leptodactylids, hylids, and bufonids) form a monophyletic assemblage with a single synapomorphy: the presence of a conical subacrosomal perforatorium. This structure is analogous to, rather than homologous with, the perforatorium in archaeobatrachians, which differs notably in being an endonuclear structure. The hylid-leptodactylid-bufonid assemblage is the sister-group of the Myobatrachidae (Australian 'leptodactylids). Myobatrachids are distinguished by two, albeit weak, synapomorphies, the presence of well-defined pericentriolar material, and the extension of the axial rod up the centriolar fossa, the latter condition approached in the bufonid Nectophrynoides. The bufonid, leptodactylid (sensu strictu), and hylid families are united, and separated from myobatrachids, by a single synapomorphy: a thick collar-like cytoplasmic sheath that emanates from the centriolar region, is separated from the flagellum by a cytoplasmic canal. and contains the mitochondria. Litoria fallax, L. gracilenta, and L. lesueuri are associated by a unique synapomorphy, hypermorphosis of the minor fibre (juxta-axonemal fibre), though this is approached in Bufo bufo. However, there is no spermatological evidence supporting the recognition of Australian hylids (pelodryadids) as a group distinct from the remaining eubufonoids and, specifically, from the Hylidae. Evidence is presented in support of the tentative proposal that the Lissamphibia were primitively internally fertilizing.