h.r. esmaeili

Six species of the Ponyfish species (Leiognathidae) from five genera were investigated for osteological phylogeny analysis from coastal marine waters of the Northern Persian Gulf and Oman Sea. Five specimens of each species were cleared and stained for detailed osteological examination. Additionally, Diapterus auratus was selected as an out-group for comparative analysis. The resulting data matrix was analyzed to reconstruct the phylogenetic tree. Through parsimony analysis, the studied species were classified into two main clades. The first clade comprised Nuchequula gerreoides + (Aurigequla fasciata + Karalla daura). The second clade included (Deveximentum mekranense+Deveximentum ruconiu)+in Photopectoralis bindus. Results were congruent with previously reported molecular phylogenetic analysis and underscored the significance of osteological features in distinguishing taxonomic groups within the Leiognathidae family.

For most marine organisms, including fish, species diversity is very high in the Indo-Pacific region, and it reflects how past and present environmental conditions shape a link between biodiversity and ecosystem function. The distribution of a taxon in the region is due to the establishment of morphological, genetic, behavioral, and physiological aspects of species. Despite extensive surveys in the Indo-Pacific region still, there are new species and new records especially in the case of small cryptic species such as blennies. The family Blenniidae including members of the genus Entomacrodus are mostly small fishes of less than 15 cm having an elongate and slender body with a worldwide distribution. Entomacrodus comprises herbivorous combtooth blennies with about 27 species, 7 of which occur in the western Indian Ocean. In this study, the presence, general morphology, otolith shape variation, osteology, distribution, and molecular phylogenetic affinity of the reef margin blenny Entomacrodus striatus have been documented/presented from the westernmost part of the Indo-Pacific region (the Jask Port, Oman Sea). The morphological and meristic characteristics of specimens were well fit with E. striatus. The vertebral column includes 10 abdominal and 23 caudal vertebrae, for a total vertebral count of 33. Corroborating the morphological results, DNA barcoding based on mitochondrial COI confirmed that the specimens collected from the Jask Port area are conspecific with E. striatus from other Indo-Pacific localities. Entomacrodus striatus from the Oman Sea and other Indo-Pacific regions show a distinct clade sister to a clade of E. epalzeocheilos, E. niuafoouensis, and E. randalli with a closest phylogenetic relationship to E. niuafoouensis (0.108 K2P genetic distance). The presence of E. striatus in the coastal area of the Oman Sea in the Jask coastal area represents the first record of this species for the westmost of the northern Indian Ocean and markedly expands its known geographical distribution range.

The evolution of fish populations and adaptation to habitat conditions cause morphological differences between them. This study was conducted to investigate morphological variations between Southern Nase, Chondrostoma regium, populations in the sub-basins of the Persian Gulf basin, including the three-border western sub-basins, Karkheh and Karun, using geometric morphometric techniques. For this purpose, samplings were performed from the rivers of Alvand by 18 specimens, 24 from Behesht-Abad, 18 from Beshar (sub-basin of Karun), 14 from Diverab, and 6 from Homeil during 2018-2020. To extract body shape data, the left side of specimens was photographed, and 15 landmark points were digitized on obtained 2D pictures using tpsDig2. The extracted data were analyzed using multivariate analysis, including canonical variates analysis (MANOVA/CVA) and cluster analysis after GPA superimposition. The results revealed a significant difference between the Southern Nase populations of the studied rivers based on the body shape (P<0.05). The main differences in the body shape between the studied populations were in the head shape and size, body depth, snout position, and pectoral fin base. The results indicate the high phenotypic plasticity of this species in diverse habitats.

The shape diversity among populations of Scartelaos tenuis (Day 1876) from five stations (194 specimens) in the Persian Gulf, Strait of Hormuz (Qeshm Island), and the Sea of Oman were investigated. The shape variation was assessed by geometric morphometrics, using 14 morphological landmarks. The two sexes were not distinguishable by the shape. Fish samples were classified into two distinct groups, the fish from the Persian Gulf (Heleh and Asaluyeh), and the specimens of Qeshm Island and the Sea of Oman (Chahoo, Dargahan and Jask). The Persian Gulf and the Sea of Oman are characterized by specific environmental parameters of surface waters, including temperature and salinity. The shape discrepancies of Scartelaos tenuis specimens from different stations are probably because of ecological parameters of the Persian Gulf and Sea of Oman. Our results suggest that the observed pattern of morphological variation is almost some kind of polyphenism induced by distinct environmental factors.

This study describes the influences of variations in life history traits and developmental patterns of Pelophylax ridibunda. The causes of this variation were investigated by comparing observed patterns of interpopulational differences from geographic variables. The aim of the study was to investigate whether embryos and larvae from different populations of P. ridibunda show the same pattern of development when they are reared in the same conditions in the laboratory and to find out further whether if any differences appearing in the pattern among populations is environmentaly or geneticaly based. Egg masses of P. ridibunda were collected from four sites in Fars Province, Iran and reared in the same conditions. Samples from most of the developmental stages were fixed and clutch parameters were measured at early developmental stages. Morphological characters in embryos and larvae including egg diameter, growing size of embryos and larvae at different stages, external gill, cement gland and mouth parts structures were examined with light and scanning electron microscopy. Statistical analysis showed that the mean diameter of eggs and jelly coats were significantly different (p)