Insights into the divergent evolution of the oceanic squid Sthenoteuthis oualaniensis (Cephalopoda: Ommastrephidae) from the Indian Ocean

Jeena, N S and Sajikumar, K K and Rahuman, Summaya and Ragesh, N and Koya, K P Said and Chinnadurai, S and Sasikumar, Geetha and Mohamed, K S (2023) Insights into the divergent evolution of the oceanic squid Sthenoteuthis oualaniensis (Cephalopoda: Ommastrephidae) from the Indian Ocean. Integrative Zoology. pp. 1-25. ISSN 1749-4877

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Abstract

Sthenoteuthis oualaniensis is known for its complex population structure with three major transoceanic forms (viz. middle-sized, dwarf, and giant forms) whose taxonomic status has been disputed for decades. This integrated taxonomic study examines these prevenient morphotypes gathered on cruises in the Indian Ocean to ascertain their status in the evolutionary history of the species. Molecular analyses employing mitochondrial (COI, ND2) and nuclear (H3) markers revealed four genetically distinct and novel lineages of the species in the Indian Ocean, representing three morphotypes from the Arabian Sea and one from the Southern Indian Ocean. The mitochondrial-based phylograms revealed two distinct clades in the species: “dwarf forms + giant form” and “middle-sized forms,” which further branch into geographically structured evolutionary units. Species delimitation analyses recovered five distinct clades, namely, the Arabian Sea giant and dwarf forms, Equatorial, Eastern Typical, and Other Middle-sized forms, representing the consensus molecular operational taxonomic units. H3 being heterozygous could not resolve the phylogeny. Haplotype network and AMOVA analysis of mtDNA genes indicated explicit phylogeographic structuring of haplotypes, whereas these outputs and PCA results were incongruent with the morphological grouping. Phenetic features distinguishing the morphotypes were sometimes plastic and mismatched with the genotypes. The giant form was genetically close to the dwarf forms, contradicting the earlier notion that it descended from the middle-sized form. It may be assumed that the dwarf form evolved following sympatric speciation and adaptation to warm equatorial waters, while the focal features of the Western Arabian Sea guide toward allopatric speciation of the giant form.

Item Type:	Article
Uncontrolled Keywords:	Arabian Sea; haplotype network; molecular operational taxonomic units; morphotypes; PCA; phylogeny; purpleback flying squid
Subjects:	Fish and Fisheries > Fish Genetics Molluscan Fisheries > Cephalopods
Divisions:	CMFRI-Kochi > Marine Biotechnology, Fish Nutrition and Health Division Subject Area > CMFRI > CMFRI-Kochi > Marine Biotechnology, Fish Nutrition and Health Division CMFRI-Kochi > Marine Biotechnology, Fish Nutrition and Health Division Subject Area > CMFRI-Kochi > Marine Biotechnology, Fish Nutrition and Health Division CMFRI-Kochi > Marine Capture > Shellfish Fisheries Division Subject Area > CMFRI > CMFRI-Kochi > Marine Capture > Shellfish Fisheries Division CMFRI-Kochi > Marine Capture > Shellfish Fisheries Division Subject Area > CMFRI-Kochi > Marine Capture > Shellfish Fisheries Division
Depositing User:	Arun Surendran
Date Deposited:	20 Feb 2023 09:01
Last Modified:	15 Mar 2023 05:50
URI:	http://eprints.cmfri.org.in/id/eprint/16754

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