CARAPACE SPINE
Sharp projection of carapace important for classification — chief types:
(a) antennal. Spine on front margin of carapace slightly below orbit.
(b) branchiostegal. Spine on front margin of carapace or slightly behind it about halfway between antennal and pterygostomial spines.
(c) hepatic. Spine in hepatic region of carapace below lower branch of cervical groove and behind it.
(d) infraorbital. Spine on lower angle of orbit.
(e) postorbital. Spine at moderate distance behind middle of orbit.
(f) postrostral. Dorsomedian spine immediately behind rostrum.
(g) pterygostomial. Spine on anterolateral angle of carapace.
(h) suborbital. Spine at moderate distance below middle of orbit and slightly beneath it.
(i) supraorbital. Spine at moderate distance obliquely behind and above orbit (may be placed at postorbital carina) [Moore and McCormick, 1969].
(Order Cladocera):
Large, posteriorly directed, spine-like structure formed by posterodorsal extension of carapace. Relative length may be of taxonomic importance. (Syn. apical spine, posterior spine, shell spine) [Stachowitsch, 1992].
(Order Decapoda):
Sharp projection from carapace. See: carapace spines [McLaughlin, 1980].