Investigating the morphological diversity of five species of gobies of the genus Ponticola (Gobiiformes: Gobiidae) in rivers of the southern Caspian Sea basin Ehsan Shatoei Gharenjeh 1 | Soheil Eagderi 2 | Hadi Poorbagher 3 | Manoochehr Nasri 4 1. Department of Fisheries, Faculty of Natural Resources, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. E-mail: ehsan.shatoei@ut.ac.ir 2. Corresponding Author, Department of Fisheries, Faculty of Natural Resources, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. E-mail: soheil.eagderi@ut.ac.ir 3. Department of Fisheries, Faculty of Natural Resources, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. E-mail: poorbagher@ut.ac.ir 4. Department of Fisheries, Faculty of Natural Resources, Lorestan University, Khorramabad, Iran. E-mail: nasri.m@lu.ac.ir Article Info ABSTRACT Article type: Research Article Article history: Received 06 April 2024 Received in revised form 30 May 2024 Accepted 02 June 2024 Published online 22 July 2024 Keywords: Caspian Sea, Gobiidae, Morphometrics, Morphological diversity. This work aimed to investigate the morphological diversity of five species of P. syrman, P. gorlap, P. iranicus, P. patimari and P. hircaniaensis of the genus Ponticola (Gobiidae). For this purpose, the specimens of the studied species were sampled from different stations in the rivers of the southern basin of the Caspian Sea in the provinces of Guilan, Golestan, and Mazandaran, and a total of 20 morphometric characteristics were measured. Then, the morphological characteristics after standardization were compared using PCA, Kruskal-Wallis, and CVA analyses. Based on the results, all characteristics showed significant differences. The studied species, except P. iranicus and P. hircaniaensis, were completely discriminated from each other, and the most important discriminative characters were the height of the second dorsal fin, preanal length, the length of the pectoral fin, the length of the caudal peduncle, the pre dorsal length, ventral fin length, and head length. The members of the genus Ponticola are similar in terms of morphological traits; hence, it is suggested that the whole traditional morphometric characters in a PCA analysis and molecular data be used to discriminate the species in this genus. Cite this article: Shatoei Gharenjeh, E., Eagderi, S., Poorbagher, H., & Nasri, S. (2024). Investigating the morphological diversity of five species of gobies of the genus Ponticola (Gobiiformes: Gobiidae) in rivers of the southern Caspian Sea basin. Journal of Natural Environment, 77 (Special Issue), 189-197. DOI: http//doi.org/10.22059/jne.2024.376255.2666 © The Author(s). Publisher: University of Tehran Press. DOI: http//doi.org/10.22059/jne.2024.376255.2666