مجله پژوهشهای جانوری (زیست شناسی ایران)
سال سی و ششم شماره 3 (پاییز 1402)

Understanding the relationship between climate-based habitat conditions and survival is key to maintaining biodiversity in the face of rapid climate change. Water is a limiting habitat variable for amphibians because larvae must metamorphose before wetlands or ponds dry up. Changes in precipitation and temperature patterns globally affect the amount of water available, but the impact of these changes on amphibian growth, development, and survival is poorly understood. In this study, the effect of water level reduction on the growth, metamorphosis, and survival of Levant green frog (Pelophylax bedriagae) larvae in three treatments (control, moderate, and rapid water level reduction) was investigated for 129 days. In each tank, 50 larvae were subjected to the same diet with 4 replications. The results of the experiment showed that reducing the water level increases the growth rate. Treatments with moderate and rapid water reduction showed a decrease in the size of metamorphosis, a decrease in the duration of metamorphosis, and a decrease in survival compared to the control treatment. The statistical results showed that the effect of these treatments on metamorphosis time and metamorphosis size is significant but insignificant on growth rate and survival. This information can provide insight into the plasticity of this species under climate change.

Age determination in reptiles provides important information about life span, animal growth rate, age at first reproduction and other ecological parameters. In this study, age, sexual maturity and growth rate were estimated in a population consisting of 10 males and 18 females of the Caspian tortoise, Mauremys caspica siebenrocki, using the skeletochronology method in Khuzestan province. LAG lines (Lines of Arrested Growth) are formed in the periosteal tissue of the bone. Excel 2016 and SPSS 24 software were used to perform calculations and statistical analyses. The average age for males was 6.5 (range 3-11) and for females 6.9 (range 2-12) years. The age of sexual maturity for both males and females was 4 years. There is no significant difference in the average age between male and female adults (t-test, p = 0.42). None of the morphological traits showed significant differences between males and females (p > 0.05). The three characteristics of age (LAGs), body size (maxSCL) and body weight have a positive and significant relationship with each other, so that with increasing age, body size (p = 0.0001, r2 = 0.966) and body weight (p = 0.0001, r2) = 0.898), and with the increase in body size, the body weight of individuals increases (p = 0.0001, r2 = 0.915). This correlation is observed in the entire studied population (the total of two groups, male and female). The distribution of age composition between the two sexes did not show a significant difference (χ2 = 8.18, df = 10, p = 0.61).

This study was aimed to investigate the effect of salinity on phenotypic plasticity of Platy fish (Xiphophorus maculatus) during early stages of development. For this purpose, 60 platy fish fry (30 specimens in each treatment) were raised in different environments, including fresh water (0 ppt) and salt water (12 ppt), for 30 days in laboratory conditions. After the end of this period, the left side of the fish samples was photographed with a digital camera and 16 landmarks were placed on the two-dimensional images using Tpsdig2 software. After removing size and direction effects using Generalized Procrustes Analysis, landmark data were analyzed using Principal Component Analysis, Discriminant Function Analysis, Hotelling's T test and Cluster Analysis (CA). The results showed that there is a significant difference between the body shape of platy fish among the studied treatments (P<0.001). The fry that were reared in the treatment with a salinity level of 12 ppt had a shallower head and gills with a longer snout. Also, these fish had a shorter caudal peduncle with less depth compared to fresh water treatment. The results showed that with the change of environmental conditions from fresh water to salt water, the upper position of the mouth in platy fish tends to the lower position. In addition, body depth and length were lower in fish exposed to a salinity level of 12 ppt compared to the freshwater treatment. The present study showed that water salinity plays a significant role in the early life stages of platy fish.

Due to the fact that the role of high intensity interval training (HIIT) on the oxidative stress of heart tissue is not well known, the purpose of this research is to investigate the effect of 8 weeks of HIIT training on serum lipid profile, CRP level and SOD, MDA and TAC activity in the heart tissue of ovariectomized aged rats.In this study, 24 female rats with an approximate age of 13-15 months were subjected to ovariectomy one week after being kept under standard conditions. Rats were randomly divided into two groups (1) control and (2) HIIT training. The training group practiced for 8 weeks and three sessions a week. 48 hours after the last training session, blood sampling was done and serum and heart tissue samples were sent to the laboratory to measure the desired parameters.The results showed that the levels of TG and LDL/HDL in the training group were significantly lower than the control group. Also, HDL levels in the exercise group were significantly higher than the control group. However, no significant difference was observed in the levels of LDL, cholesterol and CRP in the HIIT training group and the control group. Eight weeks of intense intermittent training caused a significant increase in SOD and a significant decrease in MDA, but had no effect on TAC. According to the findings of the present research, the implementation of HIIT in oryctomized elderly rats reduces oxidative stress and improves fat profile.

The Lutjanus genus is a group of fishes with high economic and ecological value in the Oman Sea, whose species show great morphological similarity. This study aimed to compare the morphological variation of 11 species of Lutjanus genus with traditional morphometric and geometric morphometric approaches. Based on the studies conducted, 11 species of the genus Lutjanus including L. lutjanus, L. argentimaculatus, L. ehrenbergii, L. erythropterus, L. fulviflamma, L. johnii, L. lemniscatus, L. malabaricus, L. rivulatus, L. russellii, L. quinquelineatus were identified. Traditional and geometric morphometric approaches were able to distinguish most of the species of this genus from each other in counting, measuring and body shape traits respectively. Univariate and multivariate analyzes showed a relatively high agreement, so that the number of dorsal fin spines, the number of gill spines, the length of the front ventral fin, the body depth, the length of the caudal peduncle and the length of the head had the greatest role in the separation of the members of this genus. According to our results, species diversity was higher in the eastern stations of the Oman Sea (Tis and Brice) than in the western one, which could be due to ecological factors and habitat conditions. This study suggests the use of molecular analyzes to confirm the identified species and design a detailed conservation plan.

The Caspian Sea has only two species of shrimp, the scientific names of which are Palaemon adspersus Rathke 1837 and Palaemon elegans Rathke 1837. These two species have entered the Caspian Sea from the Black Sea. In the present study, the morphological characteristics of two shrimp species, P. adspersus and P. elegans, were comparatively studied. The samples were collected from Anzali port area by 500 μ mesh size Landing net, then transferred to the marine biology laboratory in 70% ethanol for preservation and later studies. Different parts of the body as well as mouthparts were studied and examined by a stereomicroscope. Based on many photographs schematic images were drawn. The results showed that the most important morphological features used to distinguish two species from each other, the differences are in rostrum (number of teeth), telson (number of setae and the size of terminal spines), maxilla 1 (lower lacinia), mandibule (palps and dental appendages of molar and incisor), which can be used as keys to identify two species.Keywords: Morphology, Mouthparts, Shrimp, Caspian Sea