6 - Sphaeromatidae::“Cute As Buttons”

Gnathia velosa Muller, 1988
Figure 104E
MIGROGERBERIDEA • MIGROGERBERIDAE 243
DIAGNOSIS 6 1.5 mm. Anterior margin of cephalon with three tubercles,
median tubercles slightly shorter and narrower than submedian pair. Dorsal
integument of cephalon and anterior three pereonites granular. Pereonite 5
about 2.5 times wider than middorsal length. Lateral lobe of mandible
notched.
RECORDS Colombia.
Gnathia virginalis Monod, 1926
Figure 104D
DIAGNOSIS 6 2.2 mm. Anterior margin of cephalon with three tubercles,
median tubercles slightly longer than submedian pair. Dorsal integument of
cephalon and anterior three pereonites granular. Pereonite 5 about 1.7 times
wider than middorsal length. Lateral lobe of mandible rounded.
RECORDS U.S. Virgin Islands, 29 m; Colombia.
Suborder Microcerberidea Lang, 1961
DIAGNOSIS Cephalon free. Mandibles with reduced palp, or lacking palp.
Maxillipedal palp of five articles. Pereon of seven free segments. Pereopod 1
subchelate; pereopods 2—7 ambulatory. Pleon of two free pleonites plus
pleotelson. Pleopod 1 in 6 usually absent. Pleopod 2 modified for copulation.
Pleopod 3 uniramous, opercular. Pleopod 4 biramous. Pleopod 5 reduced.
Uropods usually uniramous or biramous.
Family Microcerberidae Karaman, 1933b
DIAGNOSIS Eyes absent. Body elongate, slender. Antennular peduncle of
three articles; antennal peduncle of six to eight articles. Mandibular palp of
single article; molar reduced to single stout fringed spine. Maxilla 2 reduced
to single ramus bearing two distal fringed lobes. Pereopods 2—7 ambulatory,
dactyli biunguiculate.
REMARKS The species of the Microcerberidae are all very small (less than 2
mm total length) and are most often found in interstitial habitats. They have
been recorded from marine, brackish, and freshwater environments.