Müller, 1912
The subfamily Conchoecinae was treated as being monogeneric by Müller (1906) and Skogsberg (1920), but subdivided into species-groups. Although the recent trend has been to recognise these species-groups as genera, 28 of which are known from the South Atlantic waters, some are still clearly heterogeneous and probably need further subdivision before the systematics of the subfamily can be considered to be stable. So, for several of the genera it is impractical to give a meaningful description of the generic characteristics. Below a series (a to w) of characters, used to narrow down the range of species to which a specimen may belong. A good initial guide is provided by measuring the carapace length, as is the upper depth of occurrence (lower depths can be misleading because most closing nets will leak after closure).
a. Carapace with posterior dorsal corner acutely angled and developed into a long wedge, asymmetrical gland on right valve opens on the anterior margin just below the rostral incisure.
Genus Conchoecilla
b. Carapace with highly reticulate sculpture with spines at the posterior dorsal corner of both valves and tubercles at the posterior ventral corner, the armature of the male antennular e seta are paired needle-like spines (except in C. imbricata).
Genus Conchoecissa
c. Large deep-living species with highly ornamented, relatively elongate carapaces, lacking tubercles at the posterior ventral corners.
Genus Macroconchoecia
d. Small globous species with reticulate carapace sculpturing distinguished by the thin-walled setae of the antennae being bifurcate.
Genus Mikroconchoecia
e. Small species with the gland on the left valve opening on the rostrum or on the anterior third of the dorsal carapace margin.
Genus Metaconchoecia
f. Species with large and distinctive compound accessory glands opening about midway along the ventral edge of the carapace.
Genus Gaussicia
g. Species with sharply edged shoulder vaults.
Genus Group Conchoecinae (g)
h. Species with a clear row of accessory glands close to the posterior ventral corner of the left carapace valve.
Genus Group Conchoecinae (h)
i. Species with the asymmetrical gland on the left carapace valve opening well anterior of the posterior dorsal corner.
Genus Group Conchoecinae (i)
j. Species with carapace with well rounded posterior dorsal corner and curved posterior margin.
Genus Group Conchoecinae (j)
k. Species with the right asymmetrical gland opening on a tubercle over half way up the posterior margin.
Genus Group Conchoecinae (k)
l. Species with the posterior dorsal carapace corners forming an acute angle but not developed into spines, the asymmetrical gland on the right valve opens posterio-ventrally.
Genus Group Conchoecinae (l)
m. Other species with long c or d setae on the antennal endopodite.
Genus Orthoconchoecia
n. Species with the asymmetrical gland on the right valve opening some way up the posterior margin.
Genus group Conchoecinae (n)
o. Species with a spine at the posterior dorsal corner of the carapace with the asymmetrical glands in the normal positions and without other elaborations of the carapace.
Genus group Conchoecinae (o)
p. Species with the asymmetrical gland on the right valve opening at a notch just anterior to the posterior ventral corner.
Genus group Conchoecinae (p)
q. Species with large accessory glands arranged along the posterior margins of left carapace valve.
Genus Alacia
r. Species with clear longitudinal striae along the ventral region of the carapace.
Genus group Conchoecinae (r)
s. Species with carapaces tapering anteriorly, lacking postero-dorsal spines, and typified by having an accessory gland opening on the side of the right asymmetrical gland.
Genus Loricoecia
t. Species with large, well developed shoulder vaults which in juvenile stage carry a fringe of spines.
Genus group Conchoecinae (t)
u. Species with double row of triangular teeth.
Genus group Conchoecinae (u)
v. Large species (ca. 3 mm) with clear oblique striations with ventral edge either parallel to the dorsal or the maximum height near the middle.
Genus Mollicia
w. Species with rather rectangular outlines to the carapace lacking carapace spines and in most species any accessory glands.
Genus group Conchoecinae (w)