Genetic Divergence and Biogeographic Patterns in the Deep-Sea Shrimp Plesionika semilaevis Across the Western Indian Ocean

Sreelakshmy, S and Ameri, Shijin and Chakraborty, Rekha D and Laxmilatha, P and Ghosh, Shubhadeep (2026) Genetic Divergence and Biogeographic Patterns in the Deep-Sea Shrimp Plesionika semilaevis Across the Western Indian Ocean. Thalassas: An International Journal of Marine Sciences, 42. pp. 1-12. ISSN 2366-1674

Text Thalassas_2026_Rekha Devi Chakraborty.pdf Restricted to Registered users only Download (2MB) | Send Request a Copy email to cmfrilibrary@gmail.com | Request a copy

Abstract

The pattern of larval distribution and phylogeography is crucial for defining biogeographic provinces in aquatic ecosystems and biodiversity conservation. A lack of studies, especially for the Indian Ocean, has hampered the delineation of its biogeographic regimes. Samples of Plesionika semilaevis (Spence Bate 1888) were collected from the southeastern Arabian Sea, Indian Ocean, with morphological parameters recorded and partial sequences of the mitochondrial cytochrome oxidase I (COI) gene were generated. Sequences of P. semilaevis of Mozambique Channel were obtained from the GenBank. The maximum likelihood phylogenetic analysis based on both markers provides two separate clades for the Arabian Sea and Mozambique Chanel-Madagascar specimens. Intra-species genetic differences for the COI gene ranged from 4.2 to 5.4%, more than the inter-species threshold. The haplotype network analysis reveals the discontinuities in P. semilaevis distributions within the Indian Ocean, with 20 segregating sites in COI of the Arabian Sea and Mozambique Channel-Madagascar specimens. Analysis of molecular variance (AMOVA) confirms the high genetic diversity ϕST 0.99409 (P < 0.001) among the cryptic species. This study showed that P. semilaevis in the Indian Ocean comprises of two clades with unique evolutionary histories. The South Equatorial Current (SEC) and eddies in the Mozambique Channel influence distribution and connectivity, while the east-west flow of the SEC and equatorial counter-currents along with bathymetry contribute to the isolation and formation of allopatric cryptic species in the Arabian Sea.

Actions (login required)

View Item