meristic

The present study was aimed to investigate sexual dimorphism in morphometric and meristic characters of three carangid species Carangoides ferdau, Carangoides malabaricus, and Gnathanodon speciosus from the Red Sea, Egypt. The basic statistics of the morphometric indices (relative to SL or HL) of the three carangid species considered sexual dimorphism in C. ferdau, C. malabaricus, and G. speciosus regarding some indices that are size-free and valid as a discriminating tool between males and females of the examined species. The type of size allometry of males and females of the three studied species was estimated according to the bivariate concept. No sexual dimorphism was observed in the meristics characters. Additional features should be investigated to determine sexual dimorphism to facilitate the identification for conservatory purposes and correct management.

The Sexual dimorphism (SD) in body size is very common among the scorpions. In this study, the SD was investigated in two aspects of size and shape in the genus Odontobuthus Vachon, 1950 as a small genus of the family Buthidae. This genus has six fossorial species of which four are distributed in Iran. For this purpose, 43 morphometric variables, consisting of 38 metric measurements and five meristic characters were digitized in the six species, O. bidentatus, O. doriae, O. tavighiae, O. tirgari, O. sp.1 and O. sp.2. The results show that Sexual Size Dimorphism (SSD) were significant in three species: O. doriae, O. tavighiae and O. sp.2. While O. sp.1 represented a SD for more aspects of shape, O. bidentatus did not show a significant SD for all studied traits. The amount of SD in size and shape were not the same in different species. The results showed that males have larger metasoma than females even when they are pulled to the same size. Having larger metasoma may correspond to a more efficient performance during mating, predation or combat with other males, so it should be under a high sexual selection. Type II ANOVA showed a significant interaction between species and sex for shape, but not for size. It suggests that the evolution of SD for size has been in parallel for all studied species, while it has been in different directions for shape. Among meristic variables, only the number of pectin denticles were sexually dimorphic, with males having more denticles than females in all studied species.

Morphological variation of Alburnus mossulensis (Heckel, 1843) populations in Iran were investigated by collection of 705 specimens from 27 rivers of five basins, including Bushehr, Fars, Karkheh, Karun and tributaries of Tigris (Diyala) basin in Iran in 2010 by a seine net. The specimens were fixed in 10% formalin for further investigation after anesthetizing in 1% clove oil solution. Twenty-two morphometric and 11 meristic characters were examined. Morphometric characters in adjusted form and meristic characters in classified form were used for population comparison. Analysis of morphometric and meristic characters by ANOVA showed significant differences (p<0.05) in all basins for all characters except the number of dorsal and anal fin spines. Classification of meristic characters showed most specimens of all basins have eight soft rays in dorsal fin, 12 soft rays in anal fin, 19 soft rays in caudal fin, 15 soft rays in pectoral fin and nine soft rays in pelvic fin. Discriminant function analysis showed that populations from Fars and Karun Basins were different from each other and from other populations, on the other hand, populations from Diyala, Karkheh and Bushehr basins overlapped. This result may indicate that there are similar conditions in Diyala, Karkheh and Bushehr basins, resulting in more similarity amongst the populations of these basins.