The genus Callionymus from Australian waters is revised. C. ocelligena McCulloch is considered a synonym of C. calcaratus Macleay, C. limiceps sublaevis McCulloch is raised to specific level, C. macdonaldi Ogilhy is redescribed, C. kaianus moretonensis is described as a new subspecies, and C. punctatus Richardson is added to the known callionymid fishes of Australia. Sexual dimorphism and distribution are discussed.
Various aspects of the biology of C. calcaratus, C. k. moretonensis, C. calauropomus Richardson, C. belcheri and C. sublaevis are reported on.
Most of the callionymid fishes studied fed heavily upon penaeid prawns, pelecypods, and polychaetes. C. belcheri eliminated some competition with C. sublaevis during certain periods by feeding on cumaceans, while the latter fed upon prawns from the same locality. Feeding intensity was investigated. Results from a preliminary study of brain pattern suggest that these callionymid fishes are predominantly sight feeders even in deeper waters. Gustatory feeding increased slightly with depth. Great variability in topographic brain pattern was noted at the specific level.
Sex ratios in the samples taken of C. belcheri, C. sublaevis and C. k. moretonensis were close to a 1:1 ratio, while C. calauropomus had a predominance of males. C. calcaratus had a predominance of females, but considerable variation occurred on a seasonal basis.
Although considerable variation was found in spawning times and length of spawning period, the histological changes that occurred in the development of oocytes was similar. C. belcheri had the most restricted spawning period lasting about three months. Most of the species studied appeared to have planktonic larvae. Some evidence is presented suggesting that C. k. moretonensis may have a benthic larval stage, although such a condition is extremely rare among fishes.
Otoliths were found to be satisfactory structures for age and growth determinations in the callionymid fishes studied. Overlap of age groups is reported in all species, and this is mostly attributed to the lengths of spawning periods. Longevity ranged from 3 to 4- years for the species studied. Maturity was usually reached during the second year. No evidence was found to indicate that males suffer a post-spawning mortality as has been shown with C. lyra Linnaeus.
Within Moreton Bay, fishes of the genus Callionymus were preyed upon by species of the family Platycephalidae, but not by fishes of the family Synodontidae.