Key character
Species with large accessory glands arranged along the posterior margins of left carapace valve.
One species in this heterogeneous genus has already been described in Genus Group Conchoecinae (g).
¥ Alacia alata (Alacia alata), which is distinguishable on the basis of the winged extension of the shoulder vault.
The genus Alacia also includes the largest halocyprid species, which is
¥ Alacia valdiviae (Müller, 1906) (Alacia valdiviae, Alacia valdiviae 2, Alacia valdiviae 3). When alive and for some time after preservation this species is coloured bright red. It has single accessory glands postero-ventrally and postero-dorsally on each valve. It has few other characters in common with the three other species with these additional accessory glands.
Two of these species are Southern Ocean endemics:
¥ Alacia hettacra (Müller, 1906) (Alacia hettacra, Alacia hettacra 2) is the smaller and more commonly encountered species which has two accessory postero-ventral glands on the left valves only.
¥ Alacia belgicae (Müller, 1906) (Alacia belgicae, Alacia belgicae 2). Poulsen (1973) describes A. belgicae as having four accessory postero-ventral glands on the left valve, but Kock (1992) illustrates up to nine. Both species have unusual peg-like teeth as armature on the male e seta.
The remaining poorly-known species ascribed to this genus by Poulsen (1973) is
¥ Alacia leptothrix (Müller, 1906) (Alacia leptothrix). Its carapace shape and longitudinal striae are more reminiscent of Paramollicia (see Genus Group Conchoecinae (n)), but it has one postero-dorsal and two postero-ventral glands on each carapace valve.
Alacia alata is the type species for the genus.
Species information:
Genus Alacia.pct