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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]

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]

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]

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]

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 South Caspian Sea sub-basin, owing to its complex paleogeographic history and habitat diversity, represents a center of endemism and a high-priority conservation area for the gobiid genus Ponticola. However, very little is currently known about most biological aspects of these species in general, and this sub-basin is highly threatened by anthropogenic activities. Here we examined the phylogeographic patterns, genetic diversity, and population structure of the endemic Caspian Sea species P. gorlap, in this evolutionary distinctive and ecologically threatened Caspian sub-basin. Mitochondrial DNA control region sequences and otolith shape variations were analyzed from 472 individuals at seven South Caspian localities. Results showed: (i) two shared and eight private haplotypes, distinguished by shallow divergences, (ii) pairwise ΦST values among locations, ranging from − 0.052 to 1.00; with most of the highest between Sefidroud/Kaboudval and the other samples, (iii) genetic diversity was generally low, smaller at Kaboudval/Nekaroud, and highest at Babolroud, (iv) non-unimodal mismatch distribution and neutrality tests both rejected a recent demographic expansion scenario, (v) otolith shape analysis revealed significant differences among samples, the highest between Sefidroud/Kaboudval and the others, and (vi) Mantel tests confirmed that both pairwise ΦST and otolith shape differences were more correlated to each other than with geographic distances. Different scenarios are discussed to explain the observed patterns of genetic and otolith shape variations and population structure of P. gorlap, including possible roles of euryhalinity, and presence of migratory and resident forms. [ABSTRACT FROM AUTHOR]

Freshwater habitats of the Caucasus biodiversity hotspot represent a center of endemism for the gobiid genus Ponticola Iljin, 1927. Hitherto, large‐scale molecular studies, owing to restricted taxon and geographical sampling, have failed to give an elaborate picture of diversity and evolutionary history of these species. Here, to contribute to filling this gap, we assessed taxonomic diversity, phylogeography and evolutionary history for the south Caspian populations of Ponticola presently classified as P. iranicus and P. patimari, using an integrative taxonomic approach comprising an entire geographic range sampling, and analyses of mitochondrial DNA haplotypes, the head lateral line system, otolith shape, and meristic and morphometric variation. All freshwater samples of the P. syrman group belong to a monophyletic clade with two main subclades: a small subclade confined to the upper Sefidroud sub‐basin including the type locality of P. iranicus and a large subclade with three geographically constrained haplogroups (Hg1, Hg2, and Hg3), comprising the rest of the distribution. Hg1 showed an eastern distribution including the type locality of P. patimari, while Hg2 and Hg3 are sister groups with central and western‐central distributions, respectively. The freshwater clade diverged from P. syrman during the Tyurkyanian low stand (~150 m b.s.l. lasting ~0.1 Myr), while the divergence of P. iranicus and P. patimari and radiations within P. patimari took place during the Bakunian high stand (up to 50 m a.s.l. lasting ~378–480 kya). Species delimitation analyses indicated two distinct species, corresponding to each main subclade. Although the otolith shape and lateral line analyses did not reflect with phylogeographic pattern, PCA and DFA plots of meristic and morphometric data showed a clear separation of the two major subclades corresponding to P. iranicus and P. patimari, suggesting the presence of significant morphological variation meriting formal taxonomic recognition. Overall, our findings (i) reveal the presence of two freshwater endemic species in the P. syrman group, and pending further investigation, hypothesize the presence of a third cryptic species; (ii) revise and document a narrow distributional range and low diversity for P. iranicus, in contrast to a wider distributional range and high diversity for P. patimari; (iii) suggest that the climatic oscillations of the Pleistocene were associated with the cladogenesis within the P. syrman group; and (iv) allowed for the recognition of conservation units and proposition of management measures. [ABSTRACT FROM AUTHOR]

The axial skeleton morphology of eighteen aphaniid species was examined for the first time by X‐ray radiography, a non‐lethal method. The number of total vertebrae in the genus Aphanius is ranged from 26 to 29, in Aphaniops, it is ranged from 24 to 28, and in Paraphanius mento, it is ranged from 26 to 27. The vertebral column in Aphanius was often slightly curved, and it is varied from almost straight (most common) to slightly or strongly curved and straight in two others. The caudal skeleton of the family Aphaniidae is characterized by a single and completely fused hypural plate, and a total number of 9–12 branched segmented soft rays, a single and elongate epural bone. All examined species of the genus Aphanius and Paraphanius mento displayed a straight epural bone in their caudal skeleton, while it was often sinuous‐like and thick in all species of the genus Aphaniops. This study supports the assumption that a sinuous epural is likely the first detected morphological synapomorphy for the "inner" clade of Aphaniops. The family Aphaniidae is closer to Cyprinodontidae, Valenciidae and Fundulidae than other cyprinodontiforms in the caudal skeleton, which is in agreement with the multigene phylogeny of cyprinodontiforms. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are concerning emerging pollutants. Here, MPs in four edible aquatic species of different trophic levels (between ∼2 and 4), including fish species Esox lucius (Esocidae: Esocinae); Cyprinus carpio (Cyprinidae: Cyprininae); and Luciobarbus caspius (Cyprinidae: Barbinae); and the swan mussel Anodonta cygnea (Unionidae), were assessed in the Anzali freshwater ecosystem. It is a listed wetland in the Montreux record. MPs were extracted from gastrointestinal tracts (GI), gills, muscles, and skin. All the studied fish and mussels (n = 33) had MPs. MP fibres, fragments and sheets were detected in every GI examined, however, fibres were the only type of MPs in skins, muscles and gills and were the most abundant MP. The MPs found in the fish and mussels were mainly made of nylon (35% of the total MPs), polypropylene-low density polyethylene (30%), and polycarbonate (25%). The average numbers of MPs found in every fish specimen, expressed per wet body mass, had a moderate negative correlation with the condition factor (K) (MP/g - K: Pearson correlation r = −0.413, p = 0.049), and there was no significant relation with the growth factor (b) (r = −0.376; p = 0.068). Importantly, Luciobarbus caspius (with trophic level 2.7–2.8) bioaccumulated MPs and presented a strong correlation between their MP contamination and age (r = 0.916 p < 0.05). Greater gill mass (or related factors) played an important role in the accumulation of MPs, and there was a strong correlation between these factors for Esox lucius and Cyprinus carpio (r = 0.876; r = 0.846; p < 0.05 respectively). The highest MP/g gills (1.91 ± 2.65) were in the filter feeder Anodonta cygnea inhabiting the benthic zone. Esox lucius (piscivorous, trophic level 4.1) was the most contaminated species overall (a total of 83 MPs in 8 individuals, with 0.92 MP/g fish), and their gills where MPs mainly accumulated. Cyprinus carpio was the most contaminated specimen (MPs in specimens), while the number of MPs per mass unit increased with the trophic level. Their feeding and ecological behavior in the aquatic habitat affected the level of accumulation. This work includes evidence of translocation of MPs within the aquatic organisms. [Display omitted] • Speciments had up to 44 fragment MPs, Cyprinus carpio was the most contaminated by them. • The greatest frequency of MP/g, fibres, was in the gills of Anodonta cygnea. • Luciobarbus caspius bioaccumulated MPs in older individuals. • The number of MPs per gram of wet fish tissue increased with the trophic level. [ABSTRACT FROM AUTHOR]

Clupeiformes (generally known as herrings, shads and sardines) with a synapomorphy of recessus lateralis are globally distributed marine, freshwater and diadromous species classified in seven families including the family Clupeidae. In this study, a comparative analysis of the vertebral column and caudal skeleton of twelve clupeid species was conducted on the basis of X‐ray imaging and usual staining method of bones and cartilages. Several osteological features including number of principal branched caudal rays bearing with hypurals on both lobes of the caudal‐fin; number, length, arrangement and shape of epural bones; shape and length of haemal and neural spines of the penultimate vertebrae 2, 3 and 4; length and shape of parhypural; length and shape of neural arch of the urostyle; distribution of the dorsal and procurrent rays, and fusion of parhypural with preural centrum 1 (PU1) were investigated and a detailed account of these structures were provided. The results reveal that the neural spine of the 2nd, 3rd and 4th penultimate vertebrae (NSPU2, NSPU3 and NSPU4) was generally narrow and broad in lower and pointed at upper part with some variation in the size and position related to the dorsal edge of the body in different taxa. The neural arch of the urostyle (Na) has been observed as spindle, lance‐like or knife‐like. It is usually long (≥1/2 length of the NSPU2) with some modification in the studied species. Two or three curved, straight, cone‐shape or pin‐shaped epurals were found in all species with the same number in congeneric species. Opisthural cartilage (O) lays between HYP6 and PLS anteriorly, located at the tip of PLS or traversed horizontally. The presence of this cartilage made a gap between first (longest) and second unbranched caudal rays in upper part of caudal‐fin. It showed six varied shapes (e.g. fusiform, golf club‐like, horn shape, trapezoid shape, crescent and triangle) with different size in comparison with HYP6. This comparative study revealed that some osteological characters such as shape and position of opisthural cartilage, shape of neural arch of the urostyle, and number of epurals could be used as suitable features for the identification of the studied clupeids at the species and genus levels. The improved knowledge of the skeletal structures provided here, can also facilitate the correct identification of clupeid fossils. [ABSTRACT FROM AUTHOR]

The diagnostic features of otolith morphology were provided for the clupeid fishes of the Iranian brackish and marine resources to be used as diagnostic features for the identification of clupeids diversity in these regions. Fish individuals belong to 20 species belong to 13 genera, and four families were collected from the Caspian Sea, the Persian Gulf and the Makran zone of the Oman Sea. Overall, seven otolith morphotypes were distinguished, that is lanceolated (45%), fusiform (20%), boot‐like (15%) and clamp‐like, pentagonal, elliptic and rectangular (each 5%, respectively). The univariate analysis showed that all variables except shape index [sulcus area (SS)/otolith area (OS)] and ROx (roundness) were significantly different among the clupeid species. The interspecific relationships of the otoliths were analysed based on the data of otolith morphology and otolith shape indices. Both dendrograms showed somehow an obvious separation among the studied species. However, the interspecific relationships in the dendrogram based on the otolith morphology have a better resolution. These phenotypic relationships based on otolith morphology among the studied clupeids are largely consistent with the previous hypothesis on the systematics of these fishes and emphasized that the morphological and morphometric features of the otolith, which are highlighted in this study, could be adequately used as diagnostic features for the identification of clupeids diversity. [ABSTRACT FROM AUTHOR]

Information on early egg and embryogenesis is of critical importance in order to understand the basic biology, phylogenetic affinity, dietary requirement as well as environmental and ecological preference of a particular organism including fishes. Herein, we described and illustrated the life cell imaging microscopy of embryo and early development of larvae in the laboratory‐reared fish, the Kol tooth‐carp Aphanius darabensis. In A. darabensis, like several other teleost fishes, especially aphaniid, development and embryogenesis of the species initiate with external fertilization of sticky, spherical and transparent macrolecithal/telolecithal eggs with a mean diameter of 0.945–1.196 mm, and it continues with meroblastic/radial cleavage, blastulation/blastula formation, gastrulation/gastrula formation (in the result of epibolic cell migration) and organogenesis, leading to a hatched larvae of 4.5–5.2 mm in length with attached yolk sac at approximately 142 hr (at 24 ± 1°C) after fertilization which have been discussed in details. This study provides basic data for further research on reproductive biology, breeding, behaviour and conservation management of this endemic species. [ABSTRACT FROM AUTHOR]

Iran is a major freshwater fish diversity hotspot in the Middle East, and is an important zoogeographical area in west Asia, acting as the crossroads and dispersal corridor between several major biogeographical realms of the world. The topmouth gudgeon, Pseudorasbora parva was first recorded in Iran on 6 May 1991 in the Caspian Sea basin and is now widely distributed across the country. Despite widespread distribution in the Iranian inland waters, its invasion history and genetic background remain unknown. Here, based on the mitochondrial DNA control region (806 bp) sequence variation of 161 P. parva samples collected from 15 Iranian localities and additional sites in Europe and Asia, as well as a cytochrome c oxidase subunit I barcode database 615 bp) including 166 novel and archived sequences, we characterised the pattern of genetic diversity and its colonisation history in Iran. Our results show the presence of three matrilineal haplotypes in Iran belonging to two distinct lineages: (1) a widespread lineage with a common haplotype found throughout the country and one exclusive haplotype confined to the Mashkid basin, whose origin can be traced back to a single introduction of a small number of propagules from Japan and corresponded to the Iranian introduction of P. parva in the late 1980s; (2) a Chinese lineage represented by a single haplotype found in the Shafarood River of the Caspian Sea basin but also translocated to central Iran, penetrated recently to northern Iran through natural dispersal from Azerbaijan as an extension of the European wave of invasion. At the global scale, there is less genetic diversity in west Asia than in Europe and the Asian native range. At the local scale, estimates of genetic diversity in Iranian P. parva populations are extremely low but the Caspian Sea and Esfahan basins gained higher diversities from admixture of highly divergent Japanese and Chinese lineages. Our phylogenetic and species delimitation analyses also suggest the existence of multiple putative species in the native range of P. parva and stress the need of an integrative taxonomical approach based on additional morphological and nuclear DNA data. [ABSTRACT FROM AUTHOR]

The otolith and scale were analysed in the hybrid offsprings between two Aphanius species, that is, A. farsicus and A. sophiae to evaluate if they are suitable to trace hybridization. An artificial reciprocal hybridization was performed between two species. The hybrids of A. farsicus♂ × A. sophiae♀ had otoliths with long and pointed rostrum with a narrow depression in the middle of the ventral rim. The otoliths of hybrids between A. farsicus♀ × A. sophiae♂ were more close to A. sophiae♂. As a result, the otolith contour of the hybrids was intermediate to those of the parents. Therefore, we suggest that some variations observed in the otoliths of Aphanius species may be resulted by hybridization particularly when they are sympatric or has geographic overlap. Also, no remarkable differences were found between the scales of hybrids and parents. This indicated that scale morphology and surface microstructures are not suitable for tracing the hybridization. If these species are sympatric due to possible translocation, it causes the genetic introgression of a native species through hybridization. This must be particularly considered in the conservation programme of endangered A. farsicus because artificial transplantation and consequent hybridization can lead to the extinction of this critically endangered species. [ABSTRACT FROM AUTHOR]

Here, we combined archived mitochondrial sequences for Ponto-Caspian gobiids with new sequences from the south Caspian basin to assess and evaluate its gobioid diversity and taxonomy, and to provide a first mitochondrial-based phylogenetic and phylogeographic framework. We demonstrate that: (i) Proterorhinus nasalis is the tubenose goby taxon in the saline waters of the southern Caspian Sea, whereas the name Pr. semipellucidus for the Azov/northern Caspian Sea/Volga River populations is likely be resurrected depending on the outcome of an integrative taxonomical approach; (ii) the deep-water goby Ponticola bathybius should be re-assigned to the genus Neogobius, as it is the sistergroup of N. melanostomus; (iii) specimens previously identified as Po. cyrius and Po. iljini from the south Caspian basin appear conspecific with Po. iranicus and Po. gorlap, respectively, and should be omitted from the checklist of Iranian and south Caspian freshwater fishes; (iv) the low stand of the Caspian Sea during the Tyurkyanian regression is inferred to have led to the isolation and evolution of Po. iranicus; and (v) similarities in genetic background, and invasion history of Rhinogobius sp. and Pseudorasbora parva in Iran and Turkmenistan indicate that the initial introduction of both species into the region possibly originated from Japan in the 1980s. [ABSTRACT FROM AUTHOR]

The Persian Gulf and Oman Sea are characterized by an interesting paleoclimatic history and different ecological settings, and offer a unique study area to investigate the genetic structure of marine organisms including fishes. The Ornate goby Istigobius ornatus is widely distributed throughout the tropical Indo‐West Pacific including the Persian Gulf and Oman Sea. Here, we present the population structure, genetic diversity, and demographic history of four populations of I. ornatus from the latter two regions using the D‐loop marker of mitochondrial DNA. The results reveal a shallow genealogy, a star‐like haplotype network, significance of neutrality tests, and unimodal mismatch distribution. This is concordant with a recent demographic expansion of I. ornatus in the Persian Gulf and Oman Sea at about 63,000–14,000 years ago, which appears to be related to Late Pleistocene sea level fall and rise. The results of the pairwise Fst estimates imply high gene flow along the coast of the Persian Gulf, which is probably due to larval dispersion, whereas the Oman Sea population clearly differs from all Persian Gulf populations. The AMOVA result indicates that 7.74% of the variation is related to differences among ecoregions, while inter‐ and intra‐population differences explained −3.20% and 95.47% of the variation, respectively. The haplotype network depicts two groups of haplotypes, most of them were specific to the Persian Gulf. No further evidence for geographic lineage substructuring was evident. The Mantel test result indicates that isolation by distance is not the main mechanism that promoted the genetic differentiation among the studied populations of I. ornatus. We suggest that cumulative effects of ecological and geographic barriers such as salinity, oceanographic conditions, and the presence of the Strait of Hormuz have shaped the genetic structure of I. ornatus in the Persian Gulf and Oman Sea. [ABSTRACT FROM AUTHOR]

To evaluate the specific validity of the Caspian pipefish Syngnathus caspius, we used a comparative molecular species delimitation method on a COI barcode library of Syngnathus, as well as principles of genealogical concordance. Comparative species delimitation allowed us to delineate putative species without a priori assignment of individuals to nominal species, while genealogical concordance extended our species delimitation results to multiple genes, multiple codistributed species, and comparisons with biogeographic evidence. All species delimitation analyses including two topology‐based, one network‐based, and one distance‐based analysis showed genetically isolated lineages of pipefish in the Black and Caspian Sea, corresponding to S. abaster and S. caspius, respectively. Mean evolutionary divergence between the two lineages (0.029) was within the range separating species of Syngnathus (0.024–0.217). The interclade/intraclade ratio of variation was comparable to the operational criterion of divergence between clades greater or equal to 10 × the level within clades to recognize separate species. Our argument on taxonomic validity of S. caspius is also supported by the principles of genealogical concordance as a conceptual basis for recognition of biological species. As a second objective, using a limited number of S. caspius specimens from two semi‐confined water bodies along the Caspian Sea south coastal zone (i.e., Anzali Wetland in the west and Gorgan Bay in the east), we searched for a possible matrilineal structure. The retrieved phylogeographic pattern was characterized by a shallow genealogy and lineage distributions varied, most probably caused by low to modest contemporary gene flow between populations of S. caspius across the southern Caspian Sea that are linked tightly through history. [ABSTRACT FROM AUTHOR]

The fishes, which have currently named Aphanius Nardo, 1827 are the relict of the ancient ichthyofauna of the Tethys Sea. For a long time since 1827, the genus name has been subjected to revision by several researchers using mainly morphological features. Until recently, no comprehensive single- or multi-locus DNA barcoding study has been conducted on whole members of the family Aphaniidae. In the present study, by applying four conceptually different molecular species delimitation methods, including one distance-based method, one network-based and two topology-based methods, we examined a single-locus DNA barcode library (COI) diversity for the 268 sequences within the family Aphaniidae from the Old World (57 sequences are new in the present study and 211 sequences were retrieved from NCBI database). The molecular analyses revealed a clearer picture of intra-family relationships and allowed us to clarify the generic names, and also describe a new genus for the family Aphaniidae. Results supported distinction of three major clades related to three genera within this family: i) the first clade includes the A. mento group which are placed in a new genus, Paraphanius gen. nov., found in the Orontes (= Asi) and Tigris-Euphrates River drainage, the Levant in coastal waters and the Dead Sea basin, western Jordan, and in southern Turkey in the Mediterranean basins as well as in central Turkey. This clade positioned at the base of the phylogenetic tree, (ii) the second clade contains the A. dispar-like brackish water tooth-carps which are transferred to the genus Aphaniops Hoedeman, 1951 (type species, Lebias dispar), distributed in the coastal waters around the Red Sea and the Persian Gulf basins; and (iii) the third clade, the genus Aphanius Nardo, 1827 (type species Aphanius nanus = A. fasciatus) contains all the inland and inland-related tooth-carps, which are mainly distributed in the inland waters in Turkey and Iran and also in the inland-related drainages around the Mediterranean basin. [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]

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]

Highlights Based on the result of phylogenetic character mapping: • Scale surface microstructure cannot be used for the species identification and inferring phylogenetic relationships in the genus Aphanius. • It confirms previous studies on cichlids and cyprinids, indicating that the scale shape varies with age and size of the fish. • The polygonal state in the scales of Aphanius species was a primitive shared character state. Abstract Recent studies on the analysis of the evolutionary relationships between the various taxa of the teleost fishes are based on the evaluation of the efficacy of different approaches, verifying the taxonomical congruence between the hypotheses inferred from molecular data and those from morphological data. The first objective of this study was to investigate the macro- and microscopic characterization of the body key scales for the sixteen Aphanius species, and to discuss their taxonomic significance. In addition, to reveal the phylogenetic origins of particular adaptations and to identify a possible cases of convergent evolution in scales of Aphanius species, we used a phylogenetic character mapping procedure that uses an independent data source, namely molecular data that is presumed to be functionally independent of the scale traits. Comparison of the resulted phylogenetic trees and scale data dendrogram implied that neither scale shape/scale surface morphology, nor scale surface microstructure can be used for the species identification and inferring phylogenetic relationships in the genus Aphanius. This conclusion confirms previous studies, indicating that the scale shape and ornamentations varies with habitat, age and size of the fish. We also concluded that the polygonal state in the scales of Aphanius species was a primitive shared character state. [ABSTRACT FROM AUTHOR]

Rashba and Dresselhaus spin–orbit interactions (SOIs), external fields and dielectric environment effects on hydrogenic impurity states in core–shell (ZnO/ZnS) and inverted core–shell (ZnS/ZnO) quantum dots were studied. We employed the finite difference method to achieve energy eigenvalues of the system. Our results demonstrate that SOIs, external fields and dielectric environment change drastically the impurity states. Besides, the spin degeneracy is removed when both the SOIs and the Zeeman effect are simultaneously considered. [ABSTRACT FROM AUTHOR]

Fish species of the genus Capoeta are known for their special mouth morphology (inferior mouth with the horny edge to the lower jaw), short dorsal fin with seven to nine branched rays, and their tumultuous taxonomic history. The genus Capoeta has had a complex evolutionary history with high diversification in the Middle East and is closely related with genus Luciobarbus. Earlier attempts to clarify the complex taxonomy of the group established four species groups, namely C. capoeta, C. damascina, C. tinca, and C. trutta species group. Based on this study, the C. capoeta group currently includes nine taxa (seven previous + two newly included members) and all reviewed in this paper based on morphological characters and mitochondrial genes. Capoeta macrolepis, revalidated as a distinct species, and Capoeta fusca are additional members of the C. capoeta group. Molecular time tree shows that the separation of Capoeta from its relative Luciobarbus was about 12.43-16.99 MYA. Based on the time tree presented herein, the high diversity of Capoeta in the Tigris-Euphrates system, the nesting of Capoeta within the tetraploid Luciobarbus in the mitochondrial trees and the high diversity of Luciobarbus in the Tigris-Euphrates system, it is proposed that the origination and diversification of Capoeta occurred in the palaeo-drainages of the Tigris-Euphrates system. From here, dispersion of Capoeta to the other nearby basins could have been possible through freshwater corridors during the Pliocene or Pleistocene. [ABSTRACT FROM AUTHOR]

The lined rockskipper, Istiblennius lineatus, is a species of combtooth blenny fish distributed from the Laccadive and Maldive islands, central Indian Ocean, east to Mangareva and Gambier Islands in the Pacific Ocean. It occurs as far north as Toyohama, Japan, and now it is recorded from the coastal area of the Makran Sea, Iran. Six specimens of I. lineatus were collected from 3 localities in the Iranian coast of the Makran Sea during a fish survey in November 2015. These specimens represent the first record of the species from Iranian waters as well as an extension of its known geographical range within the Indian Ocean. The morphological features of these specimens are herein described and discussed. [ABSTRACT FROM AUTHOR]

The Indo-Pacific tropical sand goby, Favonigobius reichei (Bleeker, 1854), is a gobiid fish native to estuarine and marine waters of the coasts of the Indian and the western Pacific Oceans. Four specimens of F. reichei were collected from Iranian coast of the Makran Sea during a fish survey in November 2015. The morphological features of these specimens are described and discussed. This is the first record of the species from Iranian waters and is an extension of its known range within the Indian Ocean. [ABSTRACT FROM AUTHOR]

Sexual dimorphism of two catfish, Mystus pelusius (Solander, 1794) and Glyptothorax silviae Coad, 1981, is presented based on the examination of external morphology of the fish and morphology of the gonads. We observed sexual dimorphism for M. pelusius in the shape and position of the genital papilla. In the male, the genital papilla was a small, fleshy, pointed and broad-based structure. The pelvic fin was short and did not reach back to the genital papilla. In females of M. pelusius the opening of the genital structure was without any protrusion or with a very small, dot-like structure in a few specimens, which the pelvic fin reached and overlapped. In females of G. silviae, the base of the round genital structure was wider and had a small round protrusion. The color of the female was also darker in comparison with the male. In males the base of the round genital structure was narrower and had a longer pointed protrusion. The male body color was lighter than that of females. [ABSTRACT FROM AUTHOR]

Iranocichla persa sp. n. is described from the Shur, Hasanlangi and Minab River drainages flowing into the Persian Gulf at the Strait of Hormuz in southern Iran. It is distinguished from I. hormuzensis, from the Mehran River drainage, by nuptial males having a bright orange breast and lower part of the head (vs. black), a poorly developed or invisible (vs. distinctive) "Tilapia-mark" in the dorsal in and very clear white spots making almost wavy bars or stripes on the caudal fin (vs. without or with very few white spots). Mitochondrial DNA sequence characters suggest that both Iranocichla species are closely related but form two distinct clades, diagnosable by several fixed mutations in ND2, D-loop and partially by COI sequences. Populations from Kol River drainage, which is situated in-between the Mehran and the Shur River drainages, are more similar to I. hormuzensis in terms of their male nuptial coloration but to I. persa sp. n. in their mitochondrial sequence characters. Their status requires further investigation. [ABSTRACT FROM AUTHOR]

Capoeta damascina was earlier considered by many authors as one of the most common freshwater fish species found throughout the Levant, Mesopotamia, Turkey, and Iran. However, owing to a high variation in morphological characters among and within its various populations, 17 nominal species were described, several of which were regarded as valid by subsequent revising authors. Capoeta damascina proved to be a complex of closely related species, which had been poorly studied. The current study aims at defining C. damascina and the C. damascina species complex. It investigates phylogenetic relationships among the various members of the C. damascina complex, based on mitochondrial and nuclear DNA sequences. Phylogenetic relationships were projected against paleogeographical events to interpret the geographic distribution of the taxa under consideration in relation to the area’s geological history. Samples were obtained from throughout the geographic range and were subjected to genetic analyses, using two molecular markers targeting the mitochondrial cytochrome oxidase I (n = 103) and the two adjacent divergence regions (D1-D2) of the nuclear 28S rRNA genes (n = 65). Six closely related species were recognized within the C. damascina complex, constituting two main lineages: A western lineage represented by C. caelestis, C. damascina, and C. umbla and an eastern lineage represented by C. buhsei, C. coadi, and C. saadii. The results indicate that speciation of these taxa is rather a recent event. Dispersal occurred during the Pleistocene, resulting in present-day distribution patterns. A coherent picture of the phylogenetic relationships and evolutionary history of the C. damascina species complex is drawn, explaining the current patterns of distribution as a result of paleogeographic events and ecological adaptations. [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]

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]

Introduction and Aims Methadone maintenance treatment and buprenorphine maintenance treatment are the two main therapeutic options considered for opioid replacement therapy. This study was conducted to examine the effectiveness of methadone maintenance treatment and buprenorphine maintenance treatment in Iran under usual clinical conditions. Design and Methods In this outcome research, 311 patients consented to participate in the study (77.8% response rate). The Opioid Treatment Index, General Health Questionnaire and WHOQOL-BREF questionnaire were used to assess the effectiveness of the therapeutic programs. Drop-out rate was calculated after two and six months of treatment. Results Mean dose of methadone was in an acceptable range; however, doses for buprenorphine maintenance treatment patients seemed low. The rates of attrition after two and six months of treatment were 24.2% and 44.0% in the methadone maintenance treatment group and 41.3% and 65.4% in the buprenorphine maintenance treatment group, respectively ( P < 0.001). Drug use, HIV risk-taking behaviour, and mental and physical health improved in both groups at six months of treatment, while quality of life improved only in the methadone maintenance treatment group. Discussion and Conclusions The retention seen in the buprenorphine group may in part be related to the low buprenorphine doses used. As a whole, the positive results provide support to continuation of maintenance programs. [Esmaeili H-R, Ziaddinni H, Nikravesh M-R, Baneshi M-R, Nakhaee N. Outcome evaluation of the opioid agonist maintenance treatment in Iran. Drug Alcohol Rev 2014;33:186-193] [ABSTRACT FROM AUTHOR]

A new species of tooth-carp, Aphanius arakensis sp. n., is described from the Namak Lake basin in Iran. The new species is distinguished by the congeners distributed in Iran by the following combination of characters: 10-12 anal fin rays, 28-32 lateral line scales, 10-13 caudal peduncle scales, 8-10 gill rakers, 12-19, commonly 15-16, clearly defined flank bars in males, a more prominent pigmentation along the flank added by relatively big blotches in the middle and posterior flank segments in females, a short but high antirostrum of the otolith that has a wide excisura, and a ventral rim with some small, drop-like processes, and 19 molecular apomorphies (17 transitions, two transversions) in the cytochrome b gene. It was suggested based on the phylogenetic analysis that the new species is sister to A. sophiae from the Kor River and that A. farsicus from the Maharlu Lake basin is sister to A. arakensis plus A. sophiae. A noticeable feature of the Aphanius diversity in Iran is the conservatism of the external morphology as well as morphometric and meristic characters, while distinctive differences are present in genetic characters, otolith morphology, and male color pattern. Transformation of the latter was probably driven by sexual selection. [ABSTRACT FROM AUTHOR]

The karyotypic and cytogenetic characteristics of southern catfish, Glyptothorax silviae Coad, 1981, was investigated for the first time by examining metaphase chromosome spreads obtained from gill epithelial and kidney cells. The diploid chromosome number of this species was 2n = 52. The karyotype consisted of 9 pairs of metacentric, 14 pairs of submetacentric, and 3 pairs of subtelocentric chromosomes. The arm number was 98. No heteromorphic sex chromosomes were cytologically detected in this catfish. Comparison of the chromosome number of this fish with that of the other members of subfamily Glyptosterninae shows that 2n = 52 may be regarded as characteristic of the primitive karyotype in this subfamily. [ABSTRACT FROM AUTHOR]

The karyotypic and cytological characteristics of an endemic cyprinid fish Garra persica Berg, 1913 have been investigated by examining metaphase chromosome spreads obtained from gill epithelial and kidney. The diploid chromosome number of this species was 2n = 48. The karyotype consisted of 15 pairs of metacentric, eight pairs of submetacentric and one pair of subtelocentric chromosomes (15m, 8Sm, 1St). The arm number was 94. No heteromorphic sex chromosomes were cytologically detected. Chromosome number, karyotype formula and arm number of G. persica differentiate it from G. rufa, a closely related species. [ABSTRACT FROM AUTHOR]

Abstract: The karyotypes of five tooth-carps of Iran, Aphanius persicus, Aphanius sophiae, Aphanius dispar, and Aphanius sp. have been investigated by examining metaphase chromosomes spreads obtained from gill epithelial and kidney cells. The diploid chromosome numbers of all five species were 2n =48. The karyotypes consisted of 8 pairs of submetacentric and 16 pairs of subtelocentric chromosomes in A. persicus; 4 submetacentric and 20 subtelocentric in A. sophiae; 7 submetacentric and 17 subtelocentric in Aphanius ginaonis and 8 submetacentric and 16 subtelocentric in A. dispar. It was 16 metacentric, 1 submetacentric and 7 telocentric chromosome pairs in Aphanius sp. specimen. The arm numbers were 32, 28, 31 and 32 in A. persicus, A. sophiae, A. ginaonis and A. dispar, respectively. It was 41 in Aphanius sp. Sex chromosomes were cytologically indistinguishable in these tooth-carps. Cluster analysis revealed the closeness of A. sophiae and A. persicus. According to our data A. ginaonis is related to a group of A. sophiae + A. persicus + A. dispar. [Copyright &y& Elsevier]

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]

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]

This paper is the first record of the exotic cichlid, the redbelly tilapia, Tilapia zillii (Gervais, 1848), from natural freshwater bodies of Iran, which has most likely been deliberately released to enhance fish production. The new records extend the geographical distribution range of this exotic fish. [ABSTRACT FROM AUTHOR]

Four obligate cave fish species have been recorded from Zagros in Iran: Garra typhlops (Bruun and Kaiser, 1944), G. lorestanensis (Mousavi-Sabet and Eagderi, 2016), G. tashanensis (Mousavi-Sabet, Vatandoust, Fatemi and Eagderi, 2016) and Eidinemacheilus smithi (Greenwood, 1976). So far, the only known locality of the latter has been the Loven cave. Here, we extend the known range of the Zagros blind loach (E. smithi) by reporting a new locality, the Tuveh spring, located 31 km south of Loven. We combine morphological evidence with the calculated K2P genetic divergences of 1.39% between Tuveh and Loven to confirm that these populations are conspecific. Our discovery of the second E. smithi population has implications for the conservation of this rare and vulnerable species. [ABSTRACT FROM AUTHOR]

The current status of the inland waters ichthyofauna of Iran is revised and updated. A total of 292 fish species belong to 3 classes, 24 orders, 36 families and 106 genera inhabit the inland waters of Iran. Among these, 29 species (9.9%) are exotic and 102 species (35%) are endemic. Orders with the largest numbers of species in the ichthyofauna of Iran are the Cypriniformes (182 species) followed by Gobiiformes (30 species), Cyprinodontiformes (15 species), Siluriformes (12 species), Clupeiformes (10 species), Acipenseriformes and Cichliformes (7 species) and Mugiliformes (6 species). At the family level, the Cyprinidae has the greatest number of species (74 species; 25.34% of the total species), followed by the Nemacheilidae (47 species), Leuciscidae (42 species), Gobiidae (30 species), Aphaniidae (11 species), Clupeidae (10 species), Acipenseridae and Cichlidae and Sisoridae (7 species in each) and Cobitidae and Mugilidae (6 species). [ABSTRACT FROM AUTHOR]

Tooth-carp Aphanius farsicusTeimori, Esmaeili and Reichenbacher, 2011 (Cyprinodontidae), or Farsi endemic tooth-carp, was once common in the Maharloo Lake Basin (Fars), but is disappearing now from its native region. This fish has not been listed in IUCN Red Data Book even though it should be due to criteria such as restricted distribution, destruction of spawning grounds and environmental pollution and drought. This vulnerable species has considerable ecological importance, but there are little data on its biology. The limited available data on its systematics, distribution, ecology, reproduction and threats are summarized and discussed. [ABSTRACT FROM AUTHOR]

The distribution of the Persian bleak, Alburnus hohenackeri Kessler, 1870 in Iran is described. During a survey from 2009 to 2012, we captured 30 specimens of A. hohenackeri from Choghakhor Wetland in Tigris River basin and Kardeh Dam in Harirud River basin of Iran. This is the first report of the occurrence of this species in these localities. The main distribution range in Iran is the southern part of the Caspian Sea from where it has been translocated to the other Iranian basins along with exotic Chinese carps. [ABSTRACT FROM AUTHOR]

• The morphological analysis based on scale characteristics was largely consistent with the phylogenetic relationships of the studied clupeids. • This study highlights that scale characters such as scale shape and size could be used as suitable features for the identification clupeids. • Despite the general similarity of the scales, they may properly be used to estimate the phylogenetic relationships among clupeids. The clupeid fishes are large filter-feeding organisms and have diverse groups of trophic guilds and habitats. They are known for their special body scale, which is unique among the other teleost fishes. Here, we examined microscopic characteristics of scales in 21 clupeid species from four marine resources, including the Caspian Sea, the Persian Gulf and the Gulf of Oman (Indian Ocean) and South China Sea (Haian Islands and Shanwei, Pacific Ocean) to evaluate if the scale features could properly contribute to understanding the taxonomic relationships in these fishes. Typically, the studied scales were morphologically categorized into two types; circular (i.e., true circular, cordate, discoidal) and pentagonal. Also, it was found that the number and the orientation of radii and continuous striae, the presence of pores at the posterior field, overall shape, striations on the posterior field, and scale sizes could be used as suitable features to classify the clupeids in species and genus levels. The result of morphological analysis based on the scale characteristics was largely consistent with the phylogenetic relationships of the studied species. This highlighted that morphological characteristics of the clupeid scale could adequately contribute to the understanding of taxonomic relationships in this large group. [ABSTRACT FROM AUTHOR]

The article details a study on the scale structure of cobitid fish Cobitis linea (C. linea) using different modes of structural equation modeling. Some of modes of SEM used in the study of C. linea include secondary electron image (SEI), back scattered electron image (BEI) and mixed signals of both SEI and BEI and reverse polarity. The study found that the scale of C. linea is similar to the cycloid scales of carps. The scale structure can be used to know the age-growth data of the fish.

Abstract: Length weight relationships (LWRs) were estimated for three gobiid species, Bathygobius meggitti(Hora & Mukerji, 1936), Acentrogobius dayi Koumans, 1941 and Cryptocentroides arabicus(Gmelin, 1789) (Perciformes: Gobiidae) collected from 13 localities of the Iranian intertidal coast of the Persian Gulf and Makran Sea in seven times from November 2015 to September 2017 using a hand net with mesh size 1.30 mm. The b values showed significant differences between males and females of all species except the C. arabicus. Bailey's t test revealed that b value significantly deviated from the expected cube value of 3 in three species. [ABSTRACT FROM AUTHOR]