Claus, 1874
Diagnosis
Carapace of female with straight dorsal margin and anterior taper, postero-dorsal corner angle slightly larger than 90°, posterior margin curves smoothly into the ventral margin (C. spinirostris Habitus 1). Right asymmetrical gland opening at the postero-ventral corner, the left just anterior of the hind end of the hinge. Male carapace rectangular only slight anterior taper, shoulder vaults more strongly developed (C. spinirostris Habitus 3).
Female, frontal organ undifferentiated, straight and ending in a long slender point (C. spinirostris 1). First antenna segmentation obscure, dorsal seta absent, "e" seta over twice the length of "a"-"d" setae, and with fringe of long hairs on the anterior edge.
Male, frontal organ, stem similar in length to first antenna, capitulum down-turned, terminally rounded, with few fine spines on basal half (C. spinirostris 3). First antenna, "a" seta as long as the limb, "c" seta minute, "b" and "d" setae slightly shorter than "e" seta, "e" seta armature 7-8 pairs of twisted flange-like spines giving way basally to 17-20 simple spines which alternate and are more widely spaced medially (C. spinirostris 4). Second antenna endopodite, "b" seta with two long hairs at its midpoint (C. spinirostris 5).
Remarks
Males often swarm in the neuston at night. The species undertakes diel vertical migrations of 100-200m. The occurrence of this species at latitudes >40°is seasonal, usually following the onset of stratification, probably as a result of advection. Poulsen, 1973 proposed a new genus, Spinoecia , to accommodate a combination of Müller's, 1906 obtusata group and some members of his magna group. While C. spinirostris (Conchoecia spinirostris), C. porrecta and C. vibekensis are similar, the inclusion of C. obtusata (Conchoecia obtusata) and C. parthenoda was considered unwarranted by Martens, 1979 who proposed the genus Porroecia for the former three species.
Distribution
Shallow mesopelagic/neustonic. Diel migrant. All oceans mostly at latitudes <40°. Uncommon in southern U.K. waters, 1 (R.R.S. Discovery Map).
Type specimens
None designated; status of original material uncertain.
Type locality
Original description based on material collected in the Mediterranean Sea in the vicinity of Naples and Messina.