Conchoecia lophura

Müller, 1906

Diagnosis
Carapace similar in shape to C. magna (Conchoecia magna) but larger. Female carapace tapers slightly anteriorly; ventral margin with a slight concavity; the postero-dorsal corner forms angle of about 100°; the posterior margin curves smoothly into the ventral (C. lophura Habitus 1). Male carapace with postero-dorsal corner right-angled; the postero-ventral corner is angled; the lateral aspect is more subrectangular than in the female (C. lophura Habitus 3). Right asymmetrical gland opening at the postero-ventral corner and left asymmetrical gland just anterior to the hind end of the hinge at the postero-dorsal corner. A character unique to this species is the row of large gland cells on the left valve just anterior of the postero-ventral corner (C. lophura Habitus 2, C. lophura Habitus 4); this row of gland cells clearly seen in juvenile instars making this one of the few species in which identifications of juveniles are simple and certain. Sculpturing occurs in some but not all specimens as a concentric pattern of striae over the whole of the carapace.
Female, frontal organ partially differentiated, capitulum spinose, drooping, terminating in a curved point (C. lophura 1). First antenna with dorsal seta almost as long as the limb, sensory setae are 40% the length of the "e" seta. Second antenna endopodite with spinose "b" seta, and sensory setae two thirds the length of the "f" seta.
Male, frontal organ with capitulum down-turned, slightly curved, spinose and round ended (C. lophura 3). First antenna with S-shaped "a" seta shorter than the second podomere; "c" seta short; "e" seta armature a long double row of tiny basally pointing spines (C. lophura 4). Second antenna endopodite with "b" seta carrying a long tuft of hairs near its base, the right-hand hook appendage bends through a right angle near its base and then through a further 60-70°distally (C. lophura 5).

Remarks
This species can be immediately recognised on the basis of the glands on the left valve.

Distribution
Recorded from all oceans. 60°N-48°S in Atlantic. Mostly deep mesopelagic in depth range but females also occur regularly in the bathypelagic. 1, 2, 3 (R.R.S. Discovery Map).

Type specimens
None designated; status of original material uncertain.

Type locality
Original material described from 32°N-35°S in the Atlantic and 10°N-35°S in the Indian Ocean.

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