New Information on Deep-Sea Cephalopod Ancistroteuthis lichtensteinii (Cephalopoda: Onychoteuthidae) in the Adriatic Sea

Specimens of Ancistroteuthis lichtensteinii were collected in the South Adriatic Pit during the deep-sea research performed in the South Adriatic Pit in 2010. They were caught at depths between 690 and 1.200 m with pelagic and bottom trawls. A total of 39 individuals were collected. The mantle length ranged from 13 to 129 mm, and body weight from 0.2 to 63.1 g. The length-weight relationship revealed a negative allometric growth. Morphological characteristics of upper and lower beak showed a positive correlation with mantle length and body weight. When compared to the body length, the highest growth rate in the sample was determined for the crest length and the lowest rate for the rostrum length, both for upper and lower beak. Statolith microstructure analysis showed that individual age ranged between 72 and 178 days and average age of the analysed specimens was 108 days. This study proved that juveniles of this rare species inhabit depths of the South Adriatic Sea. The general lack of information on A. lichtensteinii is not a result of its absence in the area but of the scarcity of investigations in depths of the South Adriatic Pit and use of inadequate sampling techniques for the pelagic species.