آزاد تیموری

Iran stands out as one of the world's biodiversity hotspots. Simultaneously, river fish species within the country face imminent threats from various human activities. Climate change, among other challenges, poses a significant risk to the biodiversity of Iran. Consequently, there is a critical need to anticipate potential habitat changes for freshwater fish species in response to climate change. This study focuses on evaluating the impact of climate change on the habitats of the Song fish, a species with economic value and conservation significance. The Song fish is currently classified as Vulnerable (VU) by the International Union for Conservation of Nature (IUCN), making the examination of climate change effects crucial for the future population of this species.

This study employs the MaxEnt model to predict the spatial distribution of the Song fish at two different time scales (2050 and 2080 AD) under both optimistic (RCP2.6) and pessimistic (RCP8.5) climate scenarios. The R software environment was used for the analysis. Environmental variables, including slope, annual temperature range, flow accumulation, annual precipitation, annual mean temperature, and upstream drainage area, were considered. The data related to the observations of this species have been collected from sampling and various library sources. Modeling performance in predicting species distribution has also been evaluated by the AUC (Area Under the Curve) criterion.

The model demonstrated excellent performance in predicting species distribution, as indicated by the high AUC (Area Under the Curve) criterion value of 0.989. Among the environmental variables, annual average temperature and slope emerge were the most influential factors in determining the distribution of the Song fish. Furthermore, the study revealed a projected decrease in the distribution range of this species under both optimistic and pessimistic scenarios for 2050 and 2080.

To safeguard the Song fish, it is imperative for managers to identify and implement appropriate measures. These measures should aim to mitigate the effects of climate change and alleviate threats associated with these changes.

To provide more morphological data of I. persa, in this study, morphological characteristics along with scales and otolith were studied. Fish samples were collected from Khorgo spring and transferred to the laboratory. Fish were classified into three class sizes based on standard length. Based on the results, the size of the first class was different in 12 relative traits but did not show a significant difference in the number of anal and dorsal fin rays. The general shape of otoliths was trapezoidal, and antistrostrom was not developed in small fish (SCI, SCII), while rostrum was more developed in larger fish than antistrostrum. Also, the ventral edge of the otolith was wider and serrated with age. Examination of the structure of the scales showed that in the first class, the relative length of the scales (JSL) was significantly different. Based on this study, it can be concluded that in addition to past documented molecular data, some morphological characteristics of fish bodies, otoliths, and scales can also be used to identify native Iranian cichlid fish. It was also found that phenotypic characteristics in this species show degrees of ontogenetic diversity (dependent on fish growth and length) that should be examined in detail.

In this study, environmental and climatic variables were used as independent variables to determine the habitat suitability of Cyprinion tenuiradius in Fars Province and to investigate the impact of climate change on its distribution. Modelling was conducted in an R software environment using the MaxEnt algorithm. Based on the results, the performance and accuracy of modelling were good (AUC = 0. 790). Also, the mean annual temperature and annual precipitation were the most important variables in determining the habitat suitability and distribution of this species, respectively. According to the species prediction under optimistic and pessimistic scenarios of climate change in 2050 and 2080, it is expected that the distribution range of this species will decrease slightly under the optimistic scenario of 2050 and 2080. However, the distribution range under the pessimistic scenario of 2050 will be increased slightly while in the pessimistic scenario of 2080, its suitable habitats will be significantly increased. It is recommended to use the obtained results for management and conservation purposes.

The Hormuz River System (HRS) is located in the southern coastal plain of the Zagros Mountains. Two main river drainages i.e., Mehran and Kol are known from this region, which are directly discharged to the Persian Gulf. The HRS has surprising diversity for tooth-carp fishes (family Aphaniidae). The present study aims to accentuate this notable diversity and discuss the possible cause of diversification of the tooth-carps in the HRS. To date, 15 Aphaniid species have been discovered from the Iranian drainage basins. Among them, 10 species belong to the genus Aphanius, four species belong to the genus Aphaniops, and a single species belonging to the genus Paraphanius. The HRS by having four species (22% of the Iranian tooth-carps) demonstrated the highest diversity among the other Iranian basins. Of these, one belongs to the genus Aphanius (A. darabensis) and three species belong to the genus Aphaniops (A. furcatus, A. ginaonis, and A. hormuzensis). By considering the degree of endemicity of the tooth-carps fauna relative to the territorial boundaries of drainages, the HRS has the highest endemicity, in which 31% of the Iranian endemic toothcarp species present only in the HRS. The last connection of the Makran Basin with the HRS dates back to the late Pliocene and lower Pleistocene about 1.8 million years ago. Also, the other vicariance-based events like those events related to the last glacial maximum (21000- 18000 BP), population migration during the Early Holocene sea-level rise, and the Holocene to present-day have promoted the intra- and interspecific differentiation of tooth-carps in the HRS. Also, the geological situation of the HRS provided various extreme environmental conditions, which caused a particular increase in the diversification of the tooth-carp species.

Hard Structures such as otolith and urohyal have high taxonomical value in intraspecific and interspecific studies of teleostei. In this study the intraspecies variations in morphology and morphometry of the otolith and urohyal bone were investigated in Capoeta fusca (Nikolskii, 1897). Fish specimens were collected from five populations located in Loot Basin in Southern Khorasan province and preserved in 75% ethanol. The otolith and urohyal bones were extracted by standard method, and their morphology described and morphometric characters were analyzed. Results showed the astriscus is the biggest otolith and was gyro-type with major and minor lobus. Astriscus was circle or rectangular between different populations with the inner part concave and the outer part convex. The morphometric analyses showed that populations have significant differences in L.H., RRL and RRH (P<0.05). The anterior part of the urohyal bones was without appendage, and posterior part with deep groove, dorsal plate is more front of ventral edges and its height is equal to ventral edges. End of lateral edges are with dentin structures. The urohyal morphometric analyses indicated that the most relative characters were showed significant differences between all populations. In conclusion, morphologic variations of the asteriscus and urohyal are important in intraspecies and interspecies differentiation.

The urohyal bone is a single median solid bone with anterior tip generally connected to the ventral hypohyal and to the first basibranchial and the posterior end attached to the pectoral girdle by means of muscle. This bone has been generally used for age determination، but recently it has been distinguished that its morphology is diverse in different groups of fishes such that could be used in fish taxonomy. In the present study، the morphology of urohyal in 19 species fishes from 17 genera، 6 families and 5 orders of Caspian Sea basin has been studied. Results showed that the urohyals were varied in ventral، dorsal and lateral shape، presence and number of process in the anterior part، origin of dorsal keel (distance from anterior tip)، groove in ventral portion and some other attributes. In studied cyprinid fish، the ventral part of the urohyal forms a triangular facet، which may be with or without groove. All the members of Leuciscinae have the same urohyal with two-branched anterior part. But in Cyprininae، it is not two-branched. Base on the morphology of urohyal in different groups of studied fish، it seems that Acheilognathinae، Squalliobarbinae and Leuciscinae are close to each other that the other subfamilies. In Gobiidae and Esocidae، the urohyal lack ventral sides or it is reduced. Based on the urohyal bone morphology we prepared a pictorial key for identification of some fishes of Caspian Sea basin for the first time.

The Gorm mountain with an area of 80000 ha is located in northwest of Jahrom city in Fars province, south of Iran. The area is registered as a no- hunting zone since 1995. In order to study the Herpetofauna of this region, a survey was conducted during Apr. 2007 to Apr. 2008. In this study, three quadrates (size 100×100 m) in different elevations were selected and a total of 225 pitfall traps of two different sizes were placed in the quadrates. Quadrates were visited within three weeks for three months. The trapped samples were collected, transferred to the laboratory, fixed in 10% formalin solution and identified using different valid documents. On the basis of different field works and study of trapped samples in quadrates, 20 reptile species consisting of two species of turtle and tortoise belonging to two genera and two families, eight species of snakes belonging to eight genera and three families and 10 lizard species belonging to ten genera and five families were identified and their conservation status were worked out.