Paivella Vervoort, 1965
Taxonomic description:
Female. (Description after Vervoort (1965) with modifications). Total length 1.27-1.42 mm. Cephalothorax 3.0-3.4 times longer than abdomen. Cephalon and Th1, as well as Th4-Th5 fused. Rostrum present, bifurcate. Crest absent. Posterior Th5 corners pointed, symmetrical. Genital segment symmetrical, lateral projections present (P. naporai ) or absent (P. inaciae ). A1 23-segmented, reaching the midlength of abdomen, the end of caudal rami. Re A2 longer than Ri A2, coxopodite with 1 seta, basipodite with 2 setae; Ri1 A2 with 1-2 setae, Ri2 with 7-8 terminal setae on internal lobe and 6 terminal and 1 posterior setae on external lobe, Re1 A2 with 1 seta, or it is absent, Re2 with 2-3 setae, Re3-Re6 with 1 seta each, Re7 with 3 terminal setae. Md palp base and Ri1 Md with 2 setae each, Ri2 Md with 9 terminal and 1 posterior seta. Mx1 gnathobase with 9 terminal and 4 setae on surface, second internal lobe with 3-4, third with 3-4, protopodite with 4-5, Ri with 10-11, Re with 11, and external lobe with 7-9 setae. Fourth and fifth Mx2 endites with one seta thickened into claw-like spine. In the second and third (from proximal to distal end of segment) groups of setae on Mxp protopodite 2-3 setae, in other features setation of the limb typical of Aetideidae. Re P1 3-segmented, Re1 P1 without external spine, Ri external lobe well developed, with minute spinules along external border apically. Ri P2 one-segmented, all other swimming leg rami 3-segmented. P4 coxopodite with 2 parallel rows of 4-6 spines on the posterior surface near the base of internal seta proximally.
Male. Total length 1.15 mm. Cephalothorax about 3 times longer than abdomen. Cephalon and Th1, as well as Th4-Th5 completely fused. Rostrum present, as in female. Crest absent. Th5 posterior corners rounded. A1 reaching the midlength of Abd2. A2 as in female, Ri1 and Ri2 A2 without setae. Md as in females, gnathobase reduced. Mx1 and Mx2 reduced. Mxp setation in comparison with that in female reduced. P1-P4 as in female, but Ri P2 indistinctly 2-segmented. P4 coxopodite without internal seta and rows of spines on posterior surface of segment. P5 uniramous, left one 5-segmented, apical segment ending with spine, covered with hairs; right one 4-segmented, apical segment in its distal part prolonged into needle-shaped appendage; right leg significantly shorter and reaching the midlength of third segment of left leg.
Type species: Paivella inaciae Vervoort, 1965, by original designation.
The genus Paivella includes 2 species.
Paivella inaciae Vervoort, 1965
Paivella naporai Wheeler, 1970