"Homasterope micra, new species p.534-538 FIGURES 330, 331
HOLOTYPE —USNM 136071, gravid female, length 1.14 mm, one valve and some appendages in alcohol, remaining appendages and one valve on slides.
TYPE-LOCALITY—Vema Cruise 17, station V-17-12.
ETYMOLOGY—The specific name is derived from the Greek "mikros" [ = small, little] in reference to the small size of the carapace of the new species.
PARATYPES—USNM 136072, 136075, 2 adult females; USNM 136074, 1 gravid female (not dissected); USNM 136075, 1 adult female with unextruded eggs; USNM 136076, 1 adult female without eggs. Paratypes from same sample as holotype.
DIAGNOSIS OF ADULT FEMALE—Posterior infold with 25-29 bristles between broad list and valve margin; carapace length 1.14—1.27 mm.
Seventh limb: With 12 bristles.
Furca: Each lamella with 9 claws.
DESCRIPTION OF FEMALE—Carapace tumid, small, greatest height behind middle; incisur below middle of anterior margin; surface smooth, minute pores visible under high magnification.
Infold: Rostrum with about 31 bristles plus about 13 bristles in area of incisur; infold below incisur with about 25 bristles; about 19 bristles present along ventral part of infold; 25-29 bristles present between posteroventral margin of valve and broad list near inner margin of infold; broad posteroventral list with about 21 broad transparent bristles and about 14 minute bristles; generally not more than 1 small bristle between broad bristles.
Selvage: Small lamellar prolongation present along lower margin of incisur.
Muscle scars: Central muscle scars consisting of about 15 individual scars.
Size: USNM 136071, length 1.14 mm, height 0.85 mm; USNM 136072, length 1.25 mm, height 0.90 mm; USNM 136073, length 1.17 mm, height 0.85 mm; USNM 136074, length 1.22 mm, height 0.90 mm; USNM 136075, length 1.25 mm, height 0.92 mm; USNM 136076, length 1.27 mm, height 0.95 mm.
First antenna: Medial and lateral surfaces of 1st joint with long spines forming clusters; 2nd joint with spines forming clusters on lateral and medial surfaces and along ventral and dorsal margins, and 2 spinous bristles (lateral bristle short, dorsal bristle long); ventral margin of 3rd joint with 1 short bare bristle, dorsal margin with 5 long spinous bristles; 3rd plus 4th joints quadrate; distal margin of 4th joint concave; lateral suture betweeen 3rd and 4th joints indistinct, medial suture distinct; dorsal margin of 4th joint with long bristle with short marginal spines; ventral margin with few spines and 2 slender spinous bristles, longest of these reaching distal end of 5th joint; sensory bristle of 5th joint with 6 long terminal bristles; minute spines on lateral side of distal half of dorsal margin of 5th joint; medial bristle of 6th joint spinous reaching past a-claw of 7th joint. Seventh joint: a-claw with short spines along proximal part of dorsal margin; b-bristle with 5 filaments including tip; c-bristle with 6 filaments including tip. Eighth joint: d-bristle absent or represented by minute pore or process; e-bristle bare, almost same length as b-bristle; f-bristle bent at right angle to stem, with 5 filaments including tip: g-bristle with 6 filaments including tip.
Second antenna: Protopodite with short medial bristle, long spines along dorsal margin and both long spines and short stout teeth along ventral margin. Endopodite 3-jointed with terminal filament longer than stem. Exopodite: 1st joint with clusters of long spines present distally on inner margin; bristle of 2nd joint reaching past end of 9th joint and with numerous spines along ventral margin; bristles of joints 3 to 8 with natatory hairs, and short spines along ventral margin; 9th joint with 3 bristles, 2 long with natatory hairs, 1 short with short marginal hairs; lateral spine present on 9th joint, basal spines absent on other joints.
Mandible: Coxale hirsute; ventral branch of coxale endite with 4 rows of spines, and about 4 slender spines at tip; bristle present near base of ventral branch (dorsal branch broken). Basale endite with elongate glandular peg, 4 terminal bristles, 3 triaenid bristles with 5 or 6 pairs of marginal spines excluding terminal pair, 1 fairly long dwarf bristle. Basale: 1 triaenid bristle with 3 pairs of marginal spines present on ventral margin proximal to U-shaped sclerotized area; dorsal margin with 2 long spinous terminal bristles; medial surface and dorsal part of lateral surface with clusters of long spines. Exopodite with hirsute tip and 2 short spinous bristles reaching end of 1st endopodite joint. Endopodite: 1st joint with 3 long spinous ventral bristles; dorsal margin of 2nd joint with single proximal bristle about one-third length of a-bristle, spinous a-, b-, c-, and d-bristles, 2 short medial bristles and 1 long lateral bristle between b- and c-bristles, 4 spinous medial cleaning bristles near basis of c-bristle, 1 long spinous lateral bristle between c- and d-bristles, 1 long spinous medial bristle distal to basis of d-bristle; ventral margin with 3 long spinous terminal bristles; clusters of spines present on medial surface of joint; end joint with 5 spinous bristles and long dorsal claw with minute teeth along middle of inner margin.
Maxilla: Epipodite elongate hirsute; proximal endite with 4 bristles; 3 long, 1 short; distal endite with 3 long bristles. Basale with fringe of long hairs on dorsal margin, 1 medial proximal bristle, 1 short proximal lateral bristle, 3 ventral bristles (1 proximal, 1 short distal, 1 long spinous terminal). Endopodite: 1st joint with short anterior distal bristles and 1 long 6-bristle; end joint with long terminal bristle.
Fifth limb: Dorsal margin of comb bare, hairs present at distal end. Exopodite: main hirsute bristle reaching past end of comb; 2 slender bristles present near basis of main bristle; 4 bristles present near ventral margin.
Sixth limb: Anterior margin with 1 upper and 1 lower bristle; anteroventral corner with 2 bristles plus 1 on lateral flap; posteroventral margin with 12-15 bristles; minute bristle present in upper anterior corner of medial side; medial and lateral surfaces hirsute.
Seventh limb: Each limb with 12 bristles, 6 in proximal group (3 on each side), 6 in terminal group (3 on each side), each bristle with 2 to 4 bells. Terminus with opposing combs, each with about 9 spinous teeth.
Furca: Each lamella with 9 claws, 6 primary, 3 secondary. Claws 1 and 2 with distal hairs along convex margin; primary claws with long and short teeth along concave margin.
Posterior: Posterior with long spines; dorsum rounded, spinous.
Lateral eyes: Eyes fairly small, about half diameter of medial eye, with about 10 or 11 ommatidia.
Medial eye and rod-shaped organ: Medial eye pigmented, with dorsal hairs. Rod-shaped organ 1-jointed, elongate with rounded tip, broadening near middle.
Upper lip: Lip consisting of 2 hirsute lobes, each with anterior spine; lateral hirsute flap present on each side of mouth.
Eggs: USNM 136071 with 5 eggs in brood chamber, additional eggs unextruded.
Parasites: USNM 136075 with 1 choniostomatid copepodite.
REMARKS—To be certain that this species is correctly referred to the genus Homasterope, it would be necessary to have adult males. In their absence, the presence of only 5 bristles on the dorsal margin of the Srd joint of the female has been considered sufficient evidence to place the species in Homasterope rather than Parasterope, to which it should be assigned if the male should prove to have a sensory bristle on the 5th joint of the 2nd antenna developed differently than that on the female.
COMPARISONS—The new species, H. micra, is smaller than both H. curia and H. maccaini. It also differs in having 25-29 bristles on the infold between the broad list and posterior valve margin; in this area H. curta bears about 80 bristles and H. maccaini only 1-6 bristles. The lateral eye of H. micra contains only 10 ommatidia compared to 20 in the lateral eye of H. maccaini. Only the male of H. glacialis is known. It differs from H. micra in having 7 instead of 9 claws on the caudal furca. The 7th limb of H. micra bears only 6 bristles in the proximal group, whereas, other species referred to this genus have at least 8 bristles in that group.
DISTRIBUTION—This species was collected only at the type-locality in the Subantarctic-to-35°S region west of Chile at 112 m."
(Kornicker, 1975b, p.534-538)
