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In this study, the live cell imaging microscopy of an old word cyprinodontiform fish, the Shirini toothcarp Esmaeilius shirini during its embryogenesis, is described and illustrated for the first time through the detailed morphological description and chronology of the events of all developmental stages (from fertilization to hatching). External fertilization of transparent, spherical, sticky and macrolecithal eggs bearing adhesive filaments with an average diameter of 0.83–1 mm is the first step in the ontogenesis of E. shirini. Embryogenesis continued with a process of meroblastic cleavage (approximately 2 and half h post‐fertilization, hpf), formation of blastula (blastulation), gastrula (gastrulation), neurulation, somatogenesis, organ formation (organogenesis) and pre‐hatching. The development continued with hatching (a stage between the embryonic and larval periods) at approximately 131 haf (at 24 ± 1°C). The new larvae were about 3.9–5.8 mm in length with distinct fin rays and pigmentation on the head, body and fins. Basic data from this study can be used in forthcoming investigations on the reproduction processes, breeding, behaviour and conservation of E. shirini. Fish development comprises an integrated, ordered and well‐mapped sequence of early life‐history events controlled by intrinsic and extrinsic factors. Knowledge of fish developmental stages during embryogenesis/ontogeny is essential for a better understanding of their biology, breeding criteria, phylogenetic relationships, dietary requirements, conservation plans, environmental requirements and ecological preferences. [ABSTRACT FROM AUTHOR]

The Arabian goby, Cryptocentroides arabicus (Gobiidae: Gobiinae), is a significant species in marine and brackish water ecosystems. However, limited information is available about the reproductive biology and the early life history of this species. This study aimed to understand the embryonic and pre‐larval development of C. arabicus under controlled laboratory conditions using light microscopy. Ten fish pairs were placed in five 70‐L glass aquaria, and environmental parameters were carefully monitored. After 4 months, spawning began, with each event yielding between 700 and 1500 eggs, totaling 10 spawning events. The elliptical‐shaped eggs, measuring 3.9 ± 0.1 mm in length and 1.6 mm in maximum width, hatched after 7 days and 4 h at a water temperature of 28°C. This process resulted in the identification of eight distinct larval developmental stages. Parental care by both the male and female was observed during the incubation period. Documenting the morphological changes during incubation contributes to a better understanding of the reproductive behaviour and early life history of C. arabicus. This is essential for the conservation management of marine and brackish water environments. [ABSTRACT FROM AUTHOR]

To evaluate scale morphological variability (shape, size, topological macro‐ and microstructures, ornamentation patterns) of cyprinid fishes, nine species of the genus Garra were selected and their scales from five different body regions were studied by using light and scanning electron microscopy. The scales of the examined species were thin with a central or antero–centrally positioned focus, with no cteni in the posterior part. In addition to these typical characteristics, some morphological variation was observed in the overall shape (irregular round, true oval, round‐triangular, irregular pentagonal, hexagonal, irregular hexagonal, pentagonal, ovoid), and the focus shape. These variations were mainly dependent on the fish lengths and the flank region. Morphological analysis clustered the examined species into two distinct groups. Group I consisted of G. amirhosseini and G. gymnothorax, while Group II has three subgroups, which include G. persica and G. mondica (subgroup I), G. meymehensis, G. rossica, G. nudiventris, G. hormuzensis (subgroup II), and G. rufa (subgroup III). The grouping of the studied Garra species based on the current scale morphological characters and the molecular data was only consistent for G. rossica and G. nudiventris. In addition, in the phylogenetic tree, G. persica, G. mondica, G. amirhosseini, and G. hormuzensis formed a distinct clade. However, these species did not represent close relationships in the dendrogram obtained from the scale morphology. A possible explanation why the grouping of the studied Garra species based on their scale morphological characters does not match their phylogenetic relationships is that most of the scale morphological traits vary depending on the fish size and the location of the scales on the flank. Therefore, except for some traits, that is, central or antero–centrally positioned focus, having no cteni, a specific sectioned form so called "tetra‐sectioned" type, the other examined variables are not useful enough to be used in the taxonomic study of the examined cyprinid fishes. Therefore, scale morphological characters should be used carefully for taxonomic purposes. Research Highlights: Shape, size, topological macro‐ and microstructures, and ornamentation patterns of nine species of the genus Garra were studied by using light and scanning electron microscopy.The scales were thin with a central or antero–centrally positioned focus, with no cteni in the posterior part.Morphological variation was observed in the overall shape (irregular round, true oval, round‐triangular, irregular pentagonal, hexagonal, irregular hexagonal, pentagonal, and ovoid), and the focus shape.The grouping of Garra species based on the current scale morphological characters and the molecular data was only consistent for G. rossica and G. nudiventris. [ABSTRACT FROM AUTHOR]

Otolith morphology in the toothcarps of the family Aphaniidae is an important source of taxonomic information. However, little is known about the ontogenetic variation in otolith morphology. In this study, the development of otolith morphology in different life stages of Aphaniops kruppi, an endemic toothcarp of the Arabian Peninsula, is described and discussed. The results reveal (i) a significant correlation between standard length and otolith size (length) in larval and early juvenile stages, (ii) clear differences in otolith morphology between larvae/early juveniles and adults, and (iii) a temporal link between the appearance of the sulcus on the otolith's inner face and lifestyles, that is demersal in larvae and early juveniles, and pelagic in adults. Moreover, our new data on otoliths of Ap. kruppi propose that otoliths of larvae or early juveniles of Ap. kruppi can be recognized by adults not only because of their small size but also based on their short and rounded rostrum and antirostrum and shallow, wide excisura. As the above-mentioned characteristics are also found in the otoliths of juveniles and larvae of several other studied aphaniids, it can be concluded that otoliths are not diagnostic at the species level in Ap. kruppi, and this holds for other closely related species. [ABSTRACT FROM AUTHOR]

Secondary sexual dimorphism is an interesting and stupendous subject of research study due to the fact that it is a result of sexual selection, mostly attributed to either female mate choice or male-male competition. This study aims to investigate the microscopic characterization of scales and fin rays in several aphaniids (Cyprinodontiformes: Aphaniidae) to find out the possibility of using these structures as secondary sexual dimorphism traits and discuss their taxonomic and evolutionary significance. Herein, the results reveal that (i) male individuals of aphaniid species of the genera Aphanius, Aphaniops and Paraphanius present contact organs in the forms of ctenus-like structure (in posterior margin of the scales) and spicule-like structure (in anal fin rays) that show sexual dimorphism of scales and fins; (ii) number, position, size and shape of contact organs provide taxonomic signal to distinguish members of the genus Aphaniops from two other genera; (iii) females of Aphaniops ginaonis also represent contact organs in scales but fewer than males and (iv) as the sexual dimorphism results from different sexual selection pressures acting on males and females, it provides evolutionary signals. [ABSTRACT FROM AUTHOR]

This paper presents the conclusions of a comparative analysis of six osteological features: the Structure of the vertebral column, the morphology of the predorsal bones, the vertebral column regionalization, the pterygiophore interdigitation with neural spines of dorsal fin, the pterygiophores interdigitation of with the haemal spines of the anal fin, and the intermuscular bones (IMB) and hypomerals (HM) of 12 clupeid species of the families Alosidae, Dorosomatidae, Dussumieridae and Ehiravidae. Conceivable taxonomically beneficial osteological features are nominated and utilized to discrete the clupeid species explored. Formulae for the structure of the vertebral column, the dorsal‐ and anal‐fin pterygiophores' interdigitation with the neural and haemal spines of the vertebrae are established. These morphological descriptive traits disclose a morphotype that may be related to the mode of swimming of the species searched. The morphological study of the vertebral column of the species in question permits the division of this bony structure into six morphologically different regions. This regionalization is more intricate than the classical division in abdominal and caudal parts only. [ABSTRACT FROM AUTHOR]

Freshwater fishes are facing considerable threats in the Arabian Peninsula which is considered as a highly stressed region in the Middle East. It is predicted that northern Oman is likely to face decreasing rainfall and increasing temperature in coming decades. In this study, we focused on an endemic cyprinid fish Cyprinion muscatense, as a model to investigate impacts of climate change on the mountain fishes inhibiting in this arid region. This species is expected to be strongly affected by climate change because of its limited distribution range in a montane area surrounded by lowlands and sea, limiting the species in shift to other areas. We used an ensemble approach by considering two regressions‐based species distribution modeling (SDM) algorithms: generalized linear models (GLM), and generalized additive models (GAM) to model the species habitat suitability and predict the impacts of climate change on the species habitat suitability. Based on the distribution models, the montane area located in northeastern Oman was identified as the most suitable habitat for this species. Our results indicate that, even under the minimum greenhouse gas emissions scenario (RCP 2.6), climate change will produce a high reduction in its potential future habitats. According to the results of percent contribution, elevation and annual minimum temperature were the most important variables in predicting the species suitable habitats. Results also showed that only a small percentage of suitable habitats for the species within boundaries of protected areas. Therefore, the impact of climate change on the species appears particularly alarming. Although our study was restricted to a single cyprinid freshwater species, decreases in potential habitats are likely predicted for other cyprinid fish species restricted to the mountains of this region, suggesting severe consideration is needed for aquatic systems in future conservation planning, especially for endemic freshwater fishes. [ABSTRACT FROM AUTHOR]

Members of the genus Cyprinion (Cypriniformes: Cyprinidae) are found in the Indus River basin west to the Arabian Peninsula and the Tigris‐Euphrates River drainages (Persian Gulf basin). The taxonomic status of Cyprinion including Cyprinion muscatense is poorly understood when compared to other cyprinid genera. C. muscatense has been considered as a member of the Cyprinion watsoni‐microphthalmum group and a valid species endemic to the Arabian Peninsula. Here, we redescribe C. muscatense based on an integrative morphological and molecular approach and freshly sampled material from several localities in the Oman Mountains ecoregion. The results showed that C. muscatense is distinguished from the other Cyprinion species in the Arabian Peninsula by having a short, thin, and slightly serrated last unbranched dorsal fin ray; the lower number of circumpeduncular scales; lateral line scales; and also scales between the lateral line and the dorsal‐fin origin. Subterminal mouth, presence of one pair of small barbels at the mouth corner, 3–4 unbranched and 9½–10½ dorsal‐fin branched rays, 12–14 pectoral‐fin rays, 7–8 pelvic‐fin rays, 2–3 unbranched and 6½–7½ branched anal‐fin rays, and 37–40 lateral line scales are other morphological characteristics of C. muscatense. C. muscatense is also well distinguished by molecular characters among its congeners. The first molecular phylogenetic analysis of the genus, covering all currently recognized Cyprinion species except for C. watsoni, is also presented. C. muscatense is resolved as the sister species to another endemic fish of the Arabian Peninsula Cyprinion mhalense, with a Kimura‐2‐Parameter model distance of 5.3%. [ABSTRACT FROM AUTHOR]

The investigation of secondary sexual dimorphism is a significant and exciting research topic since it has to do with sexual selection, which is connected to selecting a mate and male competitiveness. The purpose of this study was to investigate the microscopic characteristics of scales in several body parts and anal‐fin rays of nine species of the old world cyprinodontiform fishes belonging to the genera Anatolichthys and Paraphanius to find out possible secondary sexual dimorphic traits and their importance in aphaniid taxonomy. Both light and scanning microscopy revealed that scales show general characteristics of aphaniid species and present large cycloid scales of several subtype forms including cycloid‐true circular, cycloid‐chordate, oval‐reversed ovoid, polygonal‐pentagonal, quadrilateral‐square, oval‐ovoid and oval‐oblong in different body parts of fishes. Both genera had sexual dimorphism: (i) male individuals of all nine investigated species presented contact organs in the forms of ctenus‐like structure in the posterior margin of the scales and spicule‐like structure in the anal‐fin rays; (ii) caudal‐fin rays of both sexes lacked contact organs; (iii) the number, position, size and form of contact organs provided a taxonomic signal to identify the two genera; (iv) contact organs can be thought of as functional structures that keep male and female individuals in physical contact during courtship and display behaviour throughout the active phase of reproduction; (v) it can provide evolutionary signals because sexual dimorphism would come from various sexual selection pressures acting on both sexes. [ABSTRACT FROM AUTHOR]

Climate change is expected to affect freshwater water bodies worldwide, especially those located in semiarid and arid regions, including the Arabian Peninsula. Species distribution modeling has been widely used to predict the effects of climate changes on aquatic species. Occurrence records of the cichlid fish Nile tilapia, Oreochromis niloticus, were geographically mapped, followed by the implementation of species distribution models to delineate its range within the sensitive inland water system of the southeastern Arabian Peninsula. The analysis encompassed the examination of species presence data in the context of environmental variables, leading to the development of an ensemble model for habitat suitability, combining four distinct species distribution models. The findings indicated that the mean diurnal range and precipitation seasonality emerged as the most influential factors in predicting the suitability of habitats for O. niloticus. The response curve analysis indicated that the presence probability of O. niloticus decreased with increasing mean diurnal range and decreasing precipitation seasonality. The suitable distribution ranges for O. niloticus in the studied area were mainly distributed in the northeast of this region, where native/endemic fish diversity is high. The ensemble model results specified a significant impact of climate change on O. niloticus distribution, so highly suitable areas for this species will be reduced, while areas with low to moderate suitability increase slightly or remain unchanged. While O. niloticus is anticipated to display resilience and prosper under the influence of climate change, it remains paradoxical that its habitats are at risk of being compromised by climate-induced alterations. Consequently, even this resilient species stands susceptible to the repercussions of climate change. Due to the worldwide severe impacts of Nile tilapia, regular monitoring of freshwater ecosystems and fish fauna—especially in the northeast of the Arabian Peninsula, which has currently been invaded by this alien species—and protecting the region from key anthropogenic stressors are recommended to successfully conserve the freshwater fishes, which include about 22 recognized fish species in 16 genera, 10 families, 7 orders, and a class including 20 natives (7 endemic) species, out of which 13 species co-occur in sympatricity with O. niloticus. [ABSTRACT FROM AUTHOR]

The optical light microscopy and scanning electron microscopy techniques have proven to play a key and noteworthy role in the advancement of morphological studies in general, and in investigating fish scale morphology in particular. These techniques have illustrated several hidden architectural structures in scales that contribute effectively to fish identification and classification. The scale morphological and topological characters such as type, size, shape, lateral surface, focus position, circuli appearance, radii type, lepidonts, and posterior and anterior margin shapes were obtained using macro‐ and microscopic analysis in six body regions for three size classes of Garra sharq, a cyprinid endemic fish of the Arabian Peninsula. The general scale type in the studied G. sharq species was a basal elasmoid cycloid and a sectioned type. As a protective structure, the scales display several specific characteristics including firm attachment to the fish body, overlapping, and thin structure with a high surface area and high strength. These characteristics improve scale resistance to penetration, increase protection against mechanical injury and microbial infection, enhance scale flexibility, reduce fish weight (reduce friction drag), and increase scale transparency. The scales demonstrate plasticity in focus shape, size, and position in the six fish body parts and fish size groups. The examined scales displayed narrow or wide grooves (radii) in three types including primary, secondary, and tertiary present in all four scale fields (anterior, posterior, and laterals), thus a tetra‐sectioned type that is almost specific to the genus Garra. This characteristic also increases scale flexibility. The rostral margin of scales was characterized by the presence of waved and striate types. The lepidont shape and size varied being blunt, flat, pointed, tiny, sharp, short, and long. Some of these scale characters and their morphologies could be used as an alternative tool for identification, classification, and phylogenetic interpretation among the different freshwater fish species and genera. [ABSTRACT FROM AUTHOR]

In the present work, the morphological characteristics of sagitta were described and analysed for 10 species of combtooth blennies (Blenniidae) inhabiting the intertidal region of the Persian Gulf and Makran zone of Oman Sea to see the taxonomic usefulness of otoliths, especially their hidden characters for species identification. Based on the obtained results, sagitta morphology could be considered as diagnostic characters distinguishing the genera Alticus, Antennablennius, Istiblennius, Omobranchus and Parablennius showing differences related to general shape, that is, elliptic/oval to triangular; shape of antirostrum and its degree of development; the degrees of convexity of ventral and dorsal margins, and shape of ostium. The common/general otolith characters shared in the all studied combtooth blennies, is the heterosulcoid condition, which is a shared character with Perciformes and Gobiiformes. The type of sulcus is ostial, and it can be considered as a plesiomorph character shared with a basal group of actinopterygian fishes. The obtained results could be useful in taxonomical, paleontological, ecological and food and feeding habits studies. [ABSTRACT FROM AUTHOR]

Scale and otolith morphology and morphometry of Indian oil sardine Sardinella longiceps (Clupeidae) were investigated and described using light and scanning electron microscopy from eight different body regions for scales and the right and left otoliths. Scales of the Indian oil sardine show general characteristics of the other studied clupeids sand that are easily distinguishable from other fish groups, by having striae in the posterior field. The studied cycloid scales of S. longiceps were classified into three types based on the overall shape including circular (e.g. true circular and cordate), pentagonal and quadrilateral in the different body regions. The circular shape was the most common shape (87.5%), while the quadrilateral and pentagonal forms constituted 6.25% each. The results also showed that the relative scale size (J‐index) plays a desirable contribution in separating the examined populations. The results showed that the mean (or relative) scale size for all the eight regions in the Oman Sea population is larger than the Arabian Sea population. Also, another scale variable, the scale shape index (Si index), demonstrated variation (a mean of 0.86 to 1.1) in different regions of both populations from the Oman and Arabian Seas. Interestingly, here, we found that scale characters of S. longiceps not only differ from its other congeneric species, but also differ in the populations from both sides of the Oman Sea (Iran and Oman) and the Arabian Sea. It shows a positive signal for the presence of different taxonomic and management unit in the Oman and Arabian Seas. The idea should be approved by using integrated molecular and morphological traits. The otolith morphology of S. longiceps from the Oman and Arabian Seas was more conservative than the scales, which can be due to its function actin primarily as a balance organ and also enhancing hearing. The overall shape of S. longiceps otolith was lanceolate, with an elongated morphology and a well‐developed rostrum, an ostial sulcus acusticus that opens to the anterior/ dorsal margin. These morphological characters are also found in the Iranian population of S. longiceps. However, otolith displayed variation in biometric parameters among two populations and left and right otoliths and the RRL parameter were important characters to discriminate the Oman and Arabian Sea populations. Thus, the structural/biometrical variability of the otoliths may be used for population distinctness, especially in water bodies with various environmental factors, and the otolith has turned out to be a useful tool to track the life history of teleostean fishes in environments with physicochemical gradients. [ABSTRACT FROM AUTHOR]

General morphology, cephalic sensory papillae pattern, postcranial osteology, phylogenetic placement, phylogeographic pattern, and distribution of Eleotris acanthopomus Bleeker, 1853 (Teleostei: Gobiiformes: Eleotridae) from the north-western Indian Ocean (Arabian Sea) are described. The cephalic papillae pattern follows the 'open' opercular pattern, and the cheek pattern '2.4'. The vertebral column includes 10 abdominal and 14–15 caudal vertebrae, for a total vertebral count of 24–25. Corroborating the morphological results, DNA barcoding based on mitochondrial COI confirmed that the specimens collected from the Arabian Sea coastal area are conspecific with E. acanthopomus from other Indo-Pacific localities. Eleotris acanthopomus from the Arabian Sea shows the closest phylogenetic relationship to E. pellegrini (11.9% K2P genetic distance). The presence of E. acanthopomus in the coastal area of the Arabian Sea represents the first record of this genus and species for the northern Indian Ocean and markedly expands its known geographical distribution range. A preliminary phylogeographic analysis of the newly collected E. acanthopomus haplotype from the Arabian Sea and archived haplotypes from other Indo-Pacific localities suggests that extensive dispersal occurs among regional populations, most probably during the pelagic larval stage. [ABSTRACT FROM AUTHOR]

Otoliths (ear stones) of the inner ears of teleost fishes, which develop independently from the skeleton and are functionally associated with hearing and the sense of equilibrium, have significantly contributed to contemporary understanding of teleost fish systematics and evolutionary diversity. The sagittal otolith is of particular interest, since it often possesses distinctive morphological features that differ significantly among species, and have been shown to be species- and genus-specific, making it an informative taxonomic tool for ichthyologists. The otolith morphology of the Caspian Sea gobiids has not been thoroughly studied yet, with data available for only a few species. The aim of the present paper is to examine the qualitative and quantitative taxonomic and phylogenetic information in the sagittal otoliths of these species. A total of 118 otoliths representing 30 gobiid species (including 53.5% of the Caspian gobiofauna) in three gobiid lineages (i.e., Gobius, Pomatoschistus, and Acanthogobius) and 11 genera (i.e., all Ponto-Caspian gobiid genera except Babka) were analysed at taxonomic levels using an integrated descriptive and morphometric approach. The results indicated high taxonomic efficiency of otolith morphology and morphometry at taxonomic levels for the Ponto-Caspian gobiids. Our qualitative and quantitative otolith data also (i) support the monophyly of neogobiin gobies, (ii) along with other morphological and ecological data, offer a new perspective on the systematics of Neogobius bathybius, (iii) suggest the reassignment of Hyrcanogobius bergi to the genus Knipowitschia, and (iv) question the phylogenetic integrity of the four phenotypic groups previously defined in the tadpole-goby genus Benthophilus; however, more studies are needed to complete these evaluations and confirm our otolith study findings. [ABSTRACT FROM AUTHOR]

The complex architecture of fish scale has been investigated for several decades to show an existing link between scale morphology/microstructure and systematic/evolutionary relationships of fishes. In the present study, the surface architecture structure associated with the scales of a hill stream cyprinid fish Garra shamal restricted to the Hajar Mountains of the Arabian Peninsula was examined by optical light and scanning electron microscopy; (i) to describe the whole morphology, architectural design and hidden microstructures of scales in an endemic fish of the Arabian Peninsula, G. shamal, (ii) to investigate the phenotypic plasticity of scales in six selected regions of the fish body, (iii) to show an ontogenetic pattern of scale morphology in different size classes, and (iv) to study morphometric parameters for scales, and determine the most valuable indices for differentiating the scales of different body regions and the different size groups of studied species. For this purpose, scales were removed from six body regions of three size classes. The scale of G. shamal, as an ossified platelet and hard structure covering the outer part of fish in different body parts and size groups, demonstrated numerous hidden morphological and structural characteristics, and sculptural design, for example, type, shape, and size in general term, and circuli (thickness, arrangement, and relative spacing of circuli around the focus), radii (number, shape, its origin from focus), lepidonts (the texture, shape, size, orientation, and type of its attachment), and granules (shape, size, number, and configurations) in a specific term, that can contribute efficiently in fish identification and classification at the genus and species levels. Position of focus, presence of radii in all four fields of scales (anterior, posterior, and laterals) and thus tetra‐sectioned type, presence of specific tubercle arrangement on the posterior region, and some scale indices can be used as a taxonomic tool in Garra identification. Moreover, scales in G. shamal demonstrated plasticity in different fish size classes, and the origin of scales on the fish body, revealing a kind of ontogenetic variation, and the importance of key scales (scales below the dorsal fin) in the lepidological studies. The quantitative and qualitative traits described here based on the optical light microscopy and electron scanning microscopy can be implemented along with other morphological and molecular characteristics to have a better taxonomic resolution of the genus Garra. Research Highlights: The optical light microscopy (LM) and scanning electron microscopy (SEM) techniques enhanced our knowledge of scale morphology in a cyprinid fish restricted to the Arabian Peninsula.The scale of G. shamal, in different body parts and size groups, demonstrated numerous hidden morphological and structural characteristics, and sculptural design that can contribute efficiently in fish identification and classification at the genus and species levels.Tetra‐sectioned cycloid type, position of focus, presence of specific tubercle arrangement on the posterior region, and some scale indices can be used as a taxonomic tool for identification of the genus Garra.The scales showed plasticity in different fish size classes, and the origin of scales on the fish body, revealing a kind of ontogenetic variation. [ABSTRACT FROM AUTHOR]

The Glyptothorax species from the Middle East are taxonomically revised based on extensive geographic range and taxon sampling, tree topologies from mitochondrial COI and Cyt b and nuclear RAG2 markers (2532 bps), molecular species delimitation and genetic distance analyses of DNA sequences against morphometric and morphological characters. A majority-rule consensus based on conceptually different molecular species delimitation analyses combined with the Bayesian and maximum likelihood tree topologies considered all the name-bearing Iranian endemic clades of Glyptothorax, except for G. pallens (i.e., G. alidaeii, G. galaxias, G. hosseinpanahii, G. shapuri and G. silviae) as a single molecular entity. We also lent our years of experience to the morphology of Iranian Glyptothorax populations and tried to perceive consistent morphological differences, but without success. Therefore, based on this integrated molecular and morphological study, we treat G. alidaeii, G. galaxias, G. hosseinpanahii and G. shapuri as conspecific with G. silviae. Furthermore, our molecular and morphological results confirmed the first record of G. cous in Iranian waters. The species G. armeniacus, G. cous, G. daemon, G. kurdistanicus, G. pallens, G. silviae and G. steindachneri are considered as valid species. [ABSTRACT FROM AUTHOR]