01733nas a2200157   4500008004100000245006100041210006000102260000900162300001200171490000800183520128500191100002701476700001801503700001901521856003501540       1995                        eng d00aAmphibian sperm: Phylogeny and fertilization environment0 aAmphibian sperm Phylogeny and fertilization environment  c1995  a333-3420 v1663 aSperm characteristics such as the structure and position of the acrosome, the design and ultrastructure of the flagellum, the presence/absence of a neck-piece and several other fine structural details are important diagnostic features which distinguish the three orders, families and species of lissamphibians. These sperm features are also important in phylogenetic inferences. It appears that the axoneme-undulating membrane-axial rod represents a plesiomorphic character. This pattern has been simplified to a single axoneme as a secondary reversal for external fertilization in many anurans or has developed as a double axoneme as in Chiromantis xerampelina. Sperm head and acrosome length are predictive in distinguishing between terrestrial and aquatic anuran fertilizers. Sperm motility is species specific among representatives of seven of the nine South African families and motile sperm which exhibit forward progression are the rule for aquatic fertilizing anurans. In contrast, the sperm of terrestrial fertilizing anurans are immotile in a wide range of physiological/culture media with osmotic concentrations varying from 10 to 300 mOsm/kg. The term ect-terrasperm is suggested as a new terminology for amphibians which exhibit the terrestrial mode of fertilization.1 aVan Der Horst, Gerhard1 aWilson, Brian1 aChanning, Alan  u<Go to ISI>://PREV199698744907