Range extension of a bathypelagic squid, Bathyteuthis bacidifera (Cephalopoda: Bathyteuthidae), to the south Arabian Sea with special reference to its age and growth pattern

Abstract

The bathypelagic squid Bathyteuthis bacidifera was collected in an open net towed at 200 m over a bottom depth range from 1200 to 2340 m in the southern Arabian Sea, near Laccadive Archipelago (09°54′32″N; 73°39′12″E, 11°16′18″N; 72°51′09″E, and 10°48′08″N; 72°41′11″ E). Morphometric and molecular analyses are presented here. This is the first record of Bathyteuthis bacidifera from the southeastern Arabian Sea and the first description of the species at the molecular level. Specimens were collected from April 2015 to January 2016 in warmer (15.2 to 15.6 °C) and shallower (∼200 m) water than previously reported. The first observations of countable increments in the statolith of the genus Bathyteuthis are reported. The statolith microstructure of the specimens (15.6 to 39.0 mm dorsal mantle length) revealed that Bathyteuthis bacidifera is a slow growing squid, with a growth rate of 0.12 to 0.20 mm/day. The record of this rare squid from the Arabian Sea is an addition to the cephalopod fauna of India and contributes to biogeographic knowledge of this unusual deep sea family.