Prepelvic Length Research Articles

SOME BIOLOGICAL ASPECTS OF GENUS CHRYSICHTHYS IN THE EGYPTIAN INLAND WATERS

Meristic and morphometric analyses were used to compare Chrysichthys auratus auratus, Chrysichthys auratus longifilis and Chrysichthys rueppelli from commercial catch of River Nile (Al Minya) and El-Nozha Hydrodrome (Alexandria), A total of twenty-nine separate body measurements and counts were taken from each fish. Significant differences were found between Chrysichthys auratus auratus and Chrysichthys auratus longifilis in 4 out of 29 examined characters. These characters were: maximum dorsal rays height, standard length, prepelvic length and dorsal base length. Specific variations revealed that C. auratus differed from C rueppelli significantly in eighteen out of twenty-nine examined characters. The univariate and multivariate analyses . indicated that C. rueppelli was defined from G auratus as the first has larger standard length, relatively short first dorsal fin ray; larger head width; longer upper and lower jaws lengths and caudal peduncle, pectoral fin and prepelvic lengths are longer than that of C. auratus. Discriminate function analysis showed that the percent correct site allocation were 96% for C. auratus auratus, 61% for C auratus longifilis and 92% for. C. rueppelli. All analyses suggested that Chrysichthys auratus and Chrysichthys rueppelli are distinct species. The relative abundance of these species revealed that C. auratus auratus dominated the catch by number in both regions. Length-weight relationship and condition factor indicated that C auratus auratus and C. auratus longifilis inhabiting El-Nozha Hydrodrome are heavier than those from. River Nile. In addition, the natural mortality coefficient for examined species inhabiting in El-Nozha Hydrodrome was comparatively lower than those from River Nile.

Aulohalaelurus kanakorum n.sp., a new species of Catshark (Carcharhiniformes, Scyliorhinidae, Atelomycterinae) from New Caledonia

A new catshark, Aulohahaelurus kanakorum n.sp., is described from an adult male collected from off south-western New Caledonia. It is the second species in the genus Aulohalaelurus, previously restricted to western Australia. The new species is distinct from its allopatric congener, Aulohalaelurus labiosus (Waite, 1905), mainly by colour pattern, longer interdorsal space, pelvic-anal distance, shorter prepelvic length, morphology of dermal denticles and higher number of diplospondylous vertebrae. A neotype is also designated for A. labiosus (Waite, 1905).

Morphometric characters of carp minnowOsteobrama cotio (Ham.)

The morphometric and meristic characters ofOsteobrama cotio (Ham.) have been studied and the results have been discussed. The change in the relative position of dorsal and pelvic fins at different size groups of this fish has been reported for the first time. Regression of predorsal and prepelvic lengths revealed the origin of dorsal fin in front of pelvic fins below 17·5 mm size groups, whereas in fishes with total length more than 17·5 mm dorsal fin was located behind the pelvic fins. The mathematical relationships of various parameters have been described. The ratios of different body parts with total length and those of head region with head length, have been replaced by percentage values. An attempt has been made to revise the description ofO. cotio (Ham.) for the purpose of identification.