Marine Species Identification Portal : Aeginina longicornis

(Krøyer, 1843)

Description:
Body spination variable, smooth to quite spiny. Cephalon separated from pereionite 1 by suture. Length of largest male 54 mm, female 34 mm, smallest ovigerous female 9 mm.
Antenna 1 usually longer than the body, flagellum with up to 26 articles. Antenna 2 setose and usually shorter than articles 1 and 2 of antenna 1. Mouthparts quite similar to those of typical species of the genus Caprella, lacinia mobilis of right mandible not distinctly 5-toothed but with several teeth and serrations.
Propodus of gnathopod 1 with a pair of grasping spines, grasping margins of dactylus and propodus only slightly serrate. Propodus of gnathopod 2 with proximal a poison tooth and distal a notch, tooth and a rectangular projection, anterodistal margin with triangular projection; basis and ischium with anterodistal projections; carpus with posterodistal projection.
Propodus of pereiopods 5-7 with pair of proximal grasping spines.
Abdomen of male and female with 2 pairs of biarticulate appendages and a pair of lobes, medial margin of appendages with numerous minute knobs.
The degree of spination of the body is variable. Spination seems to vary from spinose in northern waters to smooth in southern; however, spiny forms have been found infrequently in the southern part of the range of this species.

Habitat:
This Arctic species is generally found in deeper water (to 2258 m), but has also been collected frequently in shallow water. The habitat does not seem to be specific because it has been collected from green, red, and brown algae, sea grass, hydroids, bryozoans and from the gut of the sea bass, Centropristis.

Distribution:
Siberian Polar Sea; Kara Sea; Novaya Zemlya; Franz Josef Land; Spitsbergen; Murmansk; Barents Sea; Norway; Denmark; Faeroe Islands; Shetland Islands; Jan Mayen; Iceland; eastern and western coasts of Greenland; Baffin Bay; east coast of North America from Newfoundland to Oregon Inlet, North Carolina.

Aeginina longicornis