Harbansus magnus Kornicker 1984

Harbansus magnus

ETYMOLOGY.—From the Latin magnus (large, great) in reference to the large size of the species.

HOLOTYPE.—USNM 158253, A-1 female on slides and in alcohol; unique specimen.

TYPE-LOCALITY.—Florida continental slope; Bureau of Land Management southeast coastal study, Sta 0275-2 (6H); 1 Mar 1977; 30°23′N, 79°57′W; depth 460 m.

DISTRIBUTION.—Known only from the type-locality (Map 3).

DIAGNOSIS.—Carapace larger than previously described species (A-1 female with length of 2.19 mm); lateral surface without ribs; protuberances on unique specimen could be artifacts (Figure 38). 2nd joint of 1st antenna with 1 dorsal bristle (Figure 39a). 2nd antenna: 1st endopodial joint with 1 short bristle; 2nd joint with long proximal and shorter terminal bristle (Figure 39b); exopodite without natatory setae. Ventral margin of 2nd endopodial joint of mandible with bristles forming 2 groups, each with 2 bristles (Figure 39c). 7th limb with 11–13 bristles; terminus with 2 pegs (Figure 39g). Each lamella of furca with 8 or 9 claws; claw 3 thinner and shorter than claw 4 (Figure 40e). Lateral eyes absent.

DESCRIPTION OF A-1 FEMALE (Figures 38–41).—Carapace elongate with long rostrum and caudal process (Figure 38); dorsal margin linear in vicinity of hinge; rostrum with lateral overlap extending past ventral margin of rostrum (Figure 41a).

Ornamentation (Figure 38): Surface with numerous ill-defined protuberances difficult to delineate because of transparency of thin-walled valves containing concretions (the protuberances could be artifacts); surface with shallow fossae and numerous long bristles; bristles more abundant in vicinity of rostrum, ventral margin, and caudal process; no bristles divided. Dorsal tip of caudal process of right valve with triangular projection (Figure 41b). 2 bristles at inner end of incisur lateral to lamellar prolongation of selvage.

Infold (Figure 41): Triangular rostrum with 5 spinous bristles forming irregular now (Figure 41a); anteroventral infold with 1 short bristle near inner end of incisur and 1 near ventral margin; 4 or 5 ridges present on anteroventral infold parallel to outer edge of valve; ventral infold without bristles; about 7 bristles, either single or in pairs, present along inner edge of infold in vicinity of caudal process; caudal process with anterior overhanding lip bearing 4 or 5 frond-like bristles (Figure 41b); outer edge of infold of caudal process with 3 minute bristles (dorsal bristle spinous) (Figure 41b).

Selvage: Wide lamellar prolongation present along free margins, except along distal edge of caudal process; prolongation divided at inner end of incisur; long fringe present along outer edge of anterior, ventral, and posterior prolongations.

Size: Length 2.19 mm, height 1.27 mm.

First Antenna (Figure 39): 1st joint bare. 2nd joint with medial spines on or near dorsal and ventral margins, and 1 spinous dorsal bristle. 3rd joint short, spinous, with 3 spinous bristles (1 ventral, 2 dorsal). 4th joint long, spinous, with 3 spinous bristles (2 ventral, 1 dorsal). Sensory bristle of 5th joint with 3 short, proximal and 3 short, distal, marginal filaments. 6th joint minute, fused to 5th, with long spinous medial bristle. 7th joint: a-bristle spinous, longer than bristle of 6th joint (distal part of a-bristle broken off on both limbs; b-bristle shorter than sensory bristle of 5th joint, with 1 marginal filament near middle and 2 distal; c-bristle about same length as sensory bristle, with 3 proximal and 3 distal marginal filaments. 8th joint: d- and e-bristles bare with blunt tips, bristles about same length as c-bristle; f-bristle about same length as c-bristle, with 5 marginal filaments (2 proximal, 3 distal); g-bristle about same length as c-bristle, with 5 marginal filaments (2 proximal, 3 distal). Filaments and stems of bristles b, c, f, and g with 1 or 2 minute terminal spines.

Second Antenna (Figure 39b): Protopodite bare. Endopodite 2-jointed: 1st joint with 1 short, proximal, anterior bristle; 2nd joint elongate, with 1 long, spinous, ventral bristle, and shorter terminal bristle. Exopodite: long 1st joint with short, tube-like, medial, terminal bristle; bristles of joints 2–8 short, with stout ventral spines (segments of bristles long, only terminal segment with narrow rings); 9th joint with 4 bristles (2 bristles with stout spines and similar to bristles of joints 2–8; 1 medium bristle and 1 very short bristle with narrow rings and short, slender, marginal spines); joints 2–8 with spines forming rows alongs distal edge (spines longer near base of bristle).

Mandible (Figure 39c): Coxale endite bifurcate with abundant, long, slender spines, and few short stout teeth near tip, no small bristle at base. Basale: dorsal margin with 3 bristles (1 near middle, 2 terminal); ventral margin with 6 bristles along medial sclerotized ridge (4 proximal, 2 distal), and 2 or 3 bristles (1 near middle, 1 or 2 distal) along lateral sclerotized ridge (on illustrated right limb of USNM 158253 medial ridge lies dorsal to lateral ridge, opposite to that of left limb); medial surface and proximal ventral margin with numerous long hairs forming rows. Exopodite with hirsute tip reaching to about midlength of dorsal margin of 1st endopodial joint, with 2 terminal bristles (distal bristle slightly longer than other). 1st endopodial joint with medial hairs and 3 ventral bristles (1 bristle minute, others long). 2nd endopodial joint: medial surface with spines forming rows, some extending onto ventral margin; ventral margin with bristles forming 2 distal groups, 2 bristles in each group (medial bristle of distal group unringed, claw-like, but with short marginal spines); dorsal margin with 2 proximal bristles and 5 bristles forming group near middle (1 short, 4 long). End joint with 3 claws and 3 bristles (dorsal claw very short, all claws with ventral spines).

Maxilla (Figure 39d–f): Endite I broad, with 6 spinous and pectinate bristles; endite III narrow, with 6 spinous and pectinate bristles; endite III narrow, with 1 proximal lateral bristle and about 7 distal bristles (Figure 39f). Precoxale and coxale with fringe of dorsal hairs; coxale with stout, hirsute, dorsal bristle. Basale with 3 terminal bristles (2 ventral, 1 medial near dorsal margin). Exopodite consisting of small lateral lobe with 3 spinous bristles (1 short, 2 long) (Figure 39d). 1st endopodial joint spinous, with stout alpha-bristle with long proximal hairs and few faint, short, distal spines, and 2 spinous beta-bristles (Figure 39d). End joint with about 9 bristles including 3 pectinate, unringed, claw-like bristles.

Fifth Limb (Figure 40a–c): Endite I with 3 bristles; endite II with 5 bristles; endite III with 9 or 10 bristles and hirsute lobe on outer edge. Exopodite: 1st joint with 2 bristles near middle of anterior margin, and 1 small bristle on outer corner; main tooth consisting of 3 pectinate teeth and 1 smooth proximal peg-like tooth; distal tooth with large anterior lobe; 1 bristle present on margin proximal to peg-like tooth (Figure 40a); 2nd joint with large triangular tooth with undulate inner edge (Figure 40b and 3 posterior bristles near midlength of inner edge (Figure 40c); 3rd joint with 2 bristles on outer lobe and 3 on inner lobe (Figure 40c); 4th and 5th joints fused, with total of 5 spinous bristles. Epipodial appendage with about 36 bristles.

Sixth Limb (Figure 40d): Endite I small, with 3 bristles; endite II slender, with 3 or 4 terminal bristles; endite III broad, with 7 terminal bristles; endite IV broad, with 4 or 5 terminal bristles. End joint narrow, not prolonged posteriorly, hirsute, with 8 or 9 bristles (6 or 7 anterior bristles spinous, 2 posterior bristles plumose); 1 spinous bristle in place of epipodial appendage.

Seventh Limb (Figure 39g,h): One limb with 7 proximal bristles (3 on one side, 4 on other), other limb with 9 proximal bristles (4 on one side, 5 on other); both limbs with 4 terminal bristles (2 on each side); all bristles strongly tapering distally (juvenile character); each bristle with 1 or 2 distal bells and marginal hairs. Terminus with comb with 5 teeth opposite 2 elongate pegs. (Small number of bells on bristles also juvenile character; additional bells visible inside of bristles of specimen examined which is preparing to molt.)

Furca (Figure 40e): Right lamella with 8 claws, left with 9; claw 3 narrower and shorter than claw 4; claw 1, 2, and 4 with groups of various sized teeth along posterior margin; remaining claws with teeth along both margins; claw 1 with stout medial teeth; claw 1 of right lamella located anterior to claw 1 of left lamella; several spines along anterior margin of right lamella; hairs present medially at bases of claws and following claws.

Bellonci Organ (Figure 40f): Elongate with about 5 sutures in middle part, broadening distally to rounded tip.

Eyes (Figure 40f): Medial eye bare, unpigmented. Lateral eyes absent.

Upper Lip (Figure 40f): With several small anterior processes.

Y-Sclerite (Figure 40g): Branching distally.

Genitalia: Oval genitalia visible on either side of new body inside integument of USNM 158253, which was about to shed its old skin.

COMPARISONS.—H. magnus is much larger than previously described species of the genus and has 8 claws on the furca, compared to 6 for previously described species. The nodes on the illustrated carapace (Figure 38) may be artifacts caused by concretions.