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A new species of potamid freshwater crab of the genus HimalayapotamonPretzmann 1966 is described here on the basis of several specimens collected from different localities in Poonch district, in Jammu province of Jammu and Kashmir, India. The new species Himalayapotamon jammuensecan be differentiated from its congeners by a suite of carapace (i.e., postorbital cristae) and gonopod (first and second) characters. In addition, molecular evidences derived from two mitochondrial gene (16srRNA and cox1) and one nuclear gene (28srRNA) supported the morphological findings. Genetically, H. jammuenseis sister to clade containing H. robertsianum(Pakistan) and H. koolooense(Punjab) which are found in close proximity to Jammu and Kashmir. Moreover, genetic distance inferred for the gene 16srRNA significantly support the species described in the study as a new species.

The science of cytogenetics deals with the structure and behavior of chromosomes during the mitotic and meiotic division of cells. Chromosomal studies have received significant attention over the past few years, especially in the disciplines of Karyology and Cytogenetics. Animal species provide a vital contribution to the knowledge of chromosome evolution. The species studied during the present investigation possessed 2n = 74 chromosomes and the karyotypic formula of Himalayapotamon emphysetumwas found to be 2n = 46 m + 10sm + 6st + 12t. Meiosis was observed to be normal and thirty-seven bivalents in the form of rings were observed during diakinesis. The individual chromosomes in the Karyotype were identified by using NOR-banding method. The data generated during the present study adds great knowledge to the karyosystematics of the crab species and will help understand interrelationships among the different crab species and also aids in undertaking hybridization programmes. Data related to the karyotypic features is considered a pre-requisite for genomic studies.