Harbansus vix Kornicker 1991

Harbansus vix

Harbansus sp. Kornicker, 1987b:217, 218, fig. 1a.

ETYMOLOGY.—From the Latin vix (with difficulty, barely).

HOLOTYPE.—USNM 158308, adult female on slide and in alcohol (unique).

TYPE LOCALITY.—Enewetak lagoon (from composite sample).

DISTRIBUTION.—Enewetak Atoll.

DESCRIPTION OF ADULT FEMALE (Figures 36–38).—Elongate with prominent rostrum and caudal process (Figure 36). Greatest height at anterior end of straight part of dorsal margin; ventral margin evenly rounded.

Ornamentation: 1 low anterodorsal rib extending posteriorly from anterior edge of rostrum; a 2nd stouter anterior rib with anterior end projecting past anterior edge of rostrum (Figures 36, 37b); posterodorsal corner of valve with low process not reaching posterior edge of valve; a 2nd low process present near ventral margin and anterior to caudal process; caudal process with subdued rib. Surface of valve with large fossae having scalloped edges (Figure 37a); fossae smaller and more widely separated in vicinity of central adductor muscle attachments near middle of valve. Long bristles on valve surface and along anterior and ventral margins (Figure 36) (not all bristles shown).

Infold: Rostral infold with 5–7 long bristles (Figure 37b); 2 bristles at inner end of incisur, 1 short bristle just ventral to inner end of incisur, and 1 short bristle at posterior end of 6 parallel ribs on anteroventral infold (Figure 37c); ventral infold just anterior to caudal process with 3 bristles; inner edge of infold of caudal process with 3 bristles; posterior infold with 1 small bristle; infold of caudal process with 7 setose bristles along anterior end of pocket (Figure 37d).

Selvage: Wide lamellar prolongation with fringe on outer edge present in vicinity of incisur, narrower along anterior and ventral margin; divided at inner end of incisur.

Carapace Size: USNM 158308, length 0.87 mm, height 0.44 mm.

First Antenna (Figure 37e): 1st joint with few distal medial spines forming row. 2nd joint with ventral and dorsal spines and 1 spinous dorsal bristle. 3rd joint with few ventral spines and 3 bristles (1 ventral, 2 dorsal). 4th joint with 5 bristles (3 ventral, 2 dorsal). 5th joint: sensory bristle with 1 or 2 short proximal filaments and 1 short and 3 long terminal filaments excluding stem (stem with 2 minute spines at tip, filaments with only 1). 6th joint fused to 5th, with medial bristle about same length as 5th joint 7th joint: a-bristle longer than bristle of 6th joint, with terminal spine; b-bristle shorter than sensory bristle of 5th joint, with 2 subterminal filaments (stem with 2 spines at tip, filaments with only 1); c-bristle about same length as sensory bristle, with 1 short proximal filament and 3 terminal filaments excluding stem (stem with 2 spines at tip, filaments with only 1). 8th joint: d- and e-bristles of equal length, same length as sensory bristle, with blunt tips; f-bristle same length as c-bristle, with 2 short proximal filaments and 3 terminal filaments (stem with 2 spines at tip, filaments with only 1); g-bristle same length as c-bristle, with 1 short proximal filament and 3 terminal filaments excluding stem (stem with 2 spines at tip, filaments with only 1).

Second Antenna (Figure 37f): Protopodite bare. Endopodite 2-jointed: 1st joint with 2 short anterior bristles; 2nd joint elongate with 1 long spinous anterior bristle and small unringed terminal peg. Exopodite 9-jointed: 1st joint elongate with small terminal medial bristle; bristle of 2nd joint reaching just past 9th joint, with 8 stout ventral spines and 1 slender dorsal spine at tip, but no natatory hairs; bristles of joints 3–8 relatively short, with stout ventral spines, 1 slender dorsal spine at tip, but no natatory hairs; 9th joint with 2 bristles (longest ventral and about same length as combined lengths of joints 5–9, with 4 ventral spines but no natatory hairs; short bristle about half length of ventral bristle and with few slender distal spines); joints 5–8 with stout basal spine (spine of 8th joint about same length as 9th joint); 9th joint with small lateral spine; joints 2–8 with minute spines forming terminal row.

Mandible (Figure 37g,h): Coxale endite spinous, bifurcate, without bristle at base. Basale: medial side hirsute, with 3 small bristles in proximal ventral corner, 1 short bristle near midlength close to ventral margin; lateral surface near ventral margin with 2 short bristles near joint midlength; ventral margin with 1 terminal bristle; dorsal margin with 1 midbristle and 2 terminal bristles. Exopodite hirsute, about half length of dorsal margin of 1st endopodial joint, with 1 long subterminal bristle and 1 short terminal bristle. Endopodite: 1st joint: ventral margin with 3 bristles (1 short, 1 medium, 1 long); 2nd joint: ventral margin with bristles forming 2 distal groups (proximal group with 2 bristles, distal group with 3 bristles including claw-like bristle) (Figure 37h); dorsal margin with bristles forming 2 groups near joint midlength (1 short bristle in proximal group, 4 in distal group); 3rd joint with 2 stout subequal claws, 1 minute dorsal claw, and 3 ringed bristles (claw-like ventral bristle of 2nd joint half length of longest claw of 3rd joint) (Figure 37h).

Maxilla (Figure 38a–c): Coxale with dorsal bristle. Endites I and II each with 6 bristles; endite III with 1 proximal and 6 distal bristles. Exopodite minute, with 1 short and 2 long bristles. Basale with 3 terminal bristles (2 ventral, 1 dorsal). Endopodite: 1st joint with 1 alpha- and 3 beta-bristles; 2nd joint with 2 stout claws, 1 shorter claw, and 6 bristles.

Fifth Limb (Figure 38d,e): With 3 endites (numbering of endites uncertain): Endite I with 2 bristles; endite II with 3 bristles; endite III with 9 bristles (Figure 38d). Exopodite: 1st joint: proximal outer edge with marginal spines and 2 bristles (distal with few long marginal spines) (Figure 38e); main tooth with 3 cuspate teem and 1 proximal smooth tooth (Figure 38e); spinous bristle on edge proximal to smooth tooth; 2nd joint: with large squarish tooth; anterior side with 1 small and 2 stout bristles; inner edge near me 3 anterior bristles with 1 small bristle (location of base of bristle obscured) (Figure 38d); inner lobe of 3rd joint well developed, with 2 terminal bristles; outer lobe of 3rd joint poorly developed, with 2 short bristles; fused 4th and 5th joints with total of 6 bristles (inner bristle with proximal bend).

Sixth Limb (Figure 38f,g): Epipodite with 1 short bristle (Figure 38g). Endite I with 3 short bristles with long proximal and short distal spines; endite III with 4 bristles with long proximal and short distal spines; endite IV with 4 or 5 bristles with long proximal and short distal spines; end joint narrow, with 5 bristles (with long proximal and short distal spines) separated by space from 2 hirsute bristles (Figure 38f,g); limb hirsute.

Seventh Limb (Figure 38h): 2 bristles in proximal group (1 on each side), each bristle with 3 or 4 bells and marginal spines; 6 bristles in distal group (3 on each side), each with 3–6 bells and marginal spines; terminus with comb of about 6 spinous teeth and opposing comb with about 4 shorter spinous teeth.

Furca (Figure 37i): Each lamella with 6 claws; claws 1, 2, 4 stout (primary), claws 3, 5, 6 narrow (secondary); claw 4 longer and stouter man claw 3; claw 1 with 2 rows of posterior teeth (teeth of medial row stouter, especially distal tooth); lamella following claw 6 with a minute spine and hairs.

Bellonci Organ: Absent.

Eyes: Medial eye absent. Lateral eye small, unpigmented, with 5 amber-colored ommatidia (Figure 38i).

Upper Lip (Figure 38i): Consisting of single hirsute lobe with minute anterior process.

Genitalia (Figure 37i): Consisting of indistinct sclerotized ring on each side of body anterior to furca.

Posterior of Body: Evenly rounded.

Y-Sclerite (Figure 37i): Branching distally.

COMPARISONS.—H. vix differs from H. slatteryi Kornicker, 1983a, in having fewer ribs on the carapace and in having a small terminal peg on the 2nd endopodial joint of the female 2nd antenna. H. vix differs from H. barnardi Kornicker, 1978, in having a narrower caudal process, an endopodite of the female 2nd antenna with 2 instead of 3 bristles on the 1st joint and a terminal peg rather than a bristle on the 2nd joint, and a shorter ventral claw-like bristle on the 2nd endopodial joint of the female mandible. H. vix differs from H. paucichelatus (Kornicker, 1958) and Streptoleberis crenulata Brady, 1880 (= genus and species inquirenda (Müller, 1912:51; Kornicker, 1978:51)) in not having natatory hairs on the exopodial bristles of the 2nd antenna. H. vix differs from H. mayeri Kornicker, 1978, H. bradmyersi Kornicker, 1978, H. dayi Kornicker, 1978, H. boweni Kornicker, 1978, and H. schornikovi (Kornicker and Caraion, 1977) in having 3 rather than 2 bristles in the distal group of bristles on the ventral margin of the 2nd endopodial joint of the mandible, and in other characters (Kornicker, 1978, table 2). H. rhabdion (Kornicker, 1970a) is much larger than H. vix, has a ventral bristle on the 2nd joint of the 1st antenna, and is without lateral eyes. H. vix also differs from other species of Harbansus in having no Organ of Bellonci.

RUTIDERMATIDAE Brady and Norman, 1896

COMPOSITION.—This family includes 3 genera: Rutiderma Brady and Norman, 1896, Alternochelata Kornicker, 1958, and Scleraner Kornicker, 1975. Only Rutiderma is in the collection from Enewetak.

DISTRIBUTION.—Rutidermatidae have been reported between latitudes of 45°N and 53°S at depths of intertidal to 560 m (possibly deeper, but records questionable (Kornicker, 1975:657; 1983b:16)), but are usually collected on the continental shelf (Cohen and Kornicker, 1987:2).

Rutiderma Brady and Norman, 1896

Rutiderma Brady and Norman. 1896:673.

TYPE SPECIES.—Rutiderma compressa Brady and Norman, 1896:673, monotypy.

COMPOSITION.—Rutiderma comprises 26 species (in 11 additional records the species was left in open nomenclature (Cohen and Kornicker, 1987:7, 8)).

DISTRIBUTION.—Same as for family. Known depth range intertidal to 317 m.