Morphological and Biochemical Systematics of Australian Freashwater and Estuarine Percichthyid Fishes

Abstract

The taxonomy and evolutionary relationships of six Australian species of the family Percichthyidae have been investigated using data obtained from comparative morphological examination of preserved specimens and from electrophoretic detection of variation in proteins extracted from liver tissue.

Members of the genera Maccullochella, Plectroplites, Macquaria and Percalates form a group of generalized percoid species that have presumably colonized Australian fresh waters from marine origins. On morphological grounds the group is here considered to belong in the basal percoid family Percichthyidae rather than in the specialized family Serranidae to which it has been previously assigned. Some doubt remains, however, as to the affinities of the genus Maccullochella.

Evidence from morphological studies, and from electrophoretic analysis of protein variation at 19 genetic loci, indicates that Maccullochella differs extensively from the other genera and that the two subgroups so formed represent separate invasions of fresh waters by already distinct marine ancestors. The Australian genera Plectroplites, Macquaria and Percalates form a closely related monophyletic group which can be assigned to a single genus. The oldest available name for such a genus is Macquavia Cuvier and Valenciennes, 1830.

Morphological and electrophoretic evidence supports the distinction of two species of Maccullochella, but no significant variation was detected between Percalates specimens initially identified as either P. colonorum or P. novemaculeatus.