Key character
Species with sharply edged shoulder vaults. There are six species belonging to different genera which have this clear characteristic.
¥ Boroecia antipoda (Müller, 1906) (Boroecia antipoda, Boroecia antipoda 2) is one of a sibling pair of bipolar species, and indeed originally described as a subspecies of the Arctic species B. borealis. It is an abundant large mesopelagic species at high latitudes with characteristically shaped anterior margins to the carapace below the incisure and numerous small spines around the posterior dorsal corner.
¥ Alacia alata (Müller, 1906) (Alacia alata, Alacia alata 2) has the shoulder vaults developed into winged extensions and is abundant at mesopelagic depths, especially in upwelling regions.
¥ Loricoecia acutimarginata (Chavtur, 1977) (Loricoecia acutimarginata, Loricoecia acutimarginata 2) is a large abyssopelagic species originally described from the North-east Pacific but appears to be cosmopolitan in very deep water. It is distinguished from the other species with sharp shoulder vaults by the depth of its occurrence and by having accessory glands probably secreting bioluminescence overlying the right asymmetrical gland.
¥ Paraconchoecia spinifera (Claus, 1890) (Paraconchoecia spinifera, Paraconchoecia spinifera 2) is a medium-sized, vertically migrating species which is abundant at shallow mesopelagic day-time depths. It has a spine at the posterior dorsal corner of the right carapace valve only and the female has a row of long hairs along the leading edge of the antennular e seta.
¥ Paraconchoecia dasyophthalma (Müller, 1906) (Paraconchoecia dasyophthalma, Paraconchoecia dasyophthalma 2) and
¥ Paraconchoecia mesadenia (Ellis, 1985) (Paraconchoecia mesadenia, Paraconchoecia mesadenia 2) are also readily distinguishable because the right asymmetrical glands open well anterior of the posterior ventral corner. In the latter, an abyssopelagic species, the gland opening is displaced more anteriorly than in the former, deep bathypelagic species.
¥ Pseudoconchoecia concentrica (Müller, 1906) (Pseudoconchoecia concentrica, Pseudoconchoecia concentrica 2, Pseudoconchoecia concentrica 3) juveniles have a fringe of spines around the shoulder vaults which are lost in the late juvenile and adult instars.
Species information:
Conchoecinae (g).pct