Harbansus mayeri Kornicker 1978

Harbansus mayeri

ETYMOLOGY.—The species is named for Mr. David Mayer, Fisheries Research Institute, University of Washington, who collected the specimens.

HOLOTYPE.—USNM 156694, ovigerous female, on slides and in alcohol.

TYPE-LOCALITY.—North side of Kiket Island, Similk Bay, Washington, 122°35'50˝W, 48°25'10˝N.

PARATYPES.—Same locality as holotype: USNM 156695, 1 ovigerous female; USNM 156696, 1 ovigerous female; USNM 156697, 5 specimens including 3 adult females.

DISTRIBUTION.—Collected only at type-locality. Water depth 8 m.

DESCRIPTION OF ADULT FEMALE (Figures 15–17; Plates 7, 8).—Carapace: Elongate with long narrow rostrum and small projecting caudal process (Figures 15, 16a); ventral margin more convex than dorsal margin; sides parallel in dorsal view.

Ornamentation: Valves without horizontal ribs, but with upper and lower posterior nodes (nodes in same position as posterior ends of upper and lower ribs present on Harbansus bradmyersi); carapace with large shallow fossae (Plates 7, 8a,b); prior to cleaning of specimen with sonic vibrator all fossae contained debris (Plate 8b). Flat bottom of fossae with small nodes with central pit having peripheral lip (Plates 7f, 8a,c,e); sides of nodes with concentric rows of minute papillae (Plate 8c,e); area between fossae with low nodes with central pit (Plate 8b,d,f); bristles numerous along ventral margin (Plate 7a); surface of carapace with few scattered bristles emerging from shallow fossae (Plates 7f, 8f); some bristles with crenulations at base (Plate 8f).

Infold: Infold of rostrum with 7 or 8 long bristles (Figures 16c, 17j); anteroventral infold with short bristle below inner end of incisur and with about 5 ridges paralleling valve margin; posterior part of ventral infold with 3 or 4 small bristles; ridge on infold of caudal process with 5 or 6 frondlike bristles (Figures 16b, 17i); 1 short bristle on posterior infold dorsal to caudal process.

Selvage: Fringed lamellar prolongation present along anterior and ventral margins; lamella divided at incisur with anterior infold overlapping ventral infold in lateral view.

Size: USNM 156694, length 0.96 mm, height 0.62 mm; USNM 156695, length 1.03 mm, height 0.66 mm; USNM 156696 (removed right valve), length 1.06 mm., height 0.60 mm; USNM 156697 (2 specimens), length 1.00 mm, height 0.60 mm, and length 1.00 mm, height 0.61 mm.

First Antenna (Figure 16d): 1st joint: medial and lateral spines. 2nd joint: 1 short dorsal bristle. 3rd joint: 3 bristles (1 ventral, 2 dorsal). 4th joint: 3 bristles (2 ventral, 1 dorsal). 5th joint: sensory

bristle with 1 short distal marginal filament, 4 long terminal filaments and 2 minute spines at tip of stem. 6th joint: medial bristle short. 7th joint: a-bristle about length of 5th joint; b-bristle about twice length of a-bristle, with 1 short distal filament and 2 minute spines at tip of stem; c-bristle about same length as sensory bristle of 5th joint, with 2 short proximal filaments, 2 short distal filaments, and 3 long terminal filaments including stem, filaments with minute spine at tip, stem with 2 minute spines at tip. 8th joint: d- and e-bristles bare, slightly longer than c-bristle, with blunt tips; f-bristle about same length as c-bristle, with 2 short proximal filaments, 1 short distal filament, and 3 long terminal filaments including stem, minute spine at tip of filaments, 2 minute spines at tip of stem; g-bristle slightly longer than f-bristle, otherwise similar to f-bristle. (Not all filaments shown on sensory bristle and bristles of 7th and 8th joints of Figure 16d.)

Second Antenna: Protopodite bare. Endopodite 3-jointed (Figure 16e): 1st joint short with 2 short anterior bristles; 2nd joint elongate with 1 long spinous ventral bristle; 3rd joint minute with short terminal bristle. Exopodite: 1st joint with small recurved terminal bristle; bristle of joints 2–8 short, with stout ventral spines, no natatory hairs; 9th joint with 2 bristles, ventral of these with spines along ventral margin and more slender distal spines along dorsal margin, dorsal bristle of 9th joint about same length as joints 5–9, with slender spines along ventral and dorsal margins, joints 2–8 with spines forming terminal row; some joints with minute basal spine; 9th joint with minute blunt spine at dorsal corner medial to base of dorsal bristle.

Mandible (Figure 16f): Coxale endite spinous, bifurcate without minute bristle at base. Basale: spinous medial side with 2 short bristles very close to ventral margin (1 proximal, 1 near middle); ventral margin with 1 fairly long, spinous, distal bristle; lateral side near ventral margin with 2 short spinous bristles and long proximal hairs; dorsal margin with 1 spinous bristle near middle and 2 terminal. Exopodite hirsute, about two-thirds length of 1st endopodite joint, with 2 terminal bristles. Endopodite: 1st joint with spines forming rows on medial surface, and 3 ventral bristles (1 very short, 2 long spinous) on ventral margin; 2nd joint with ventral margin with distal bristles forming 2 groups, each with 2 short spinous bristles, middle of dorsal margin with 5 bristles; 3rd joint with 3 bristles and 3 claws (dorsal claw very short).

Maxilla (Figure 16g,h): Endites I and II each with about 6 bristles; endite III with 1 short proximal bristle and about 6 terminal bristles. Precoxale with dorsal fringe of long hairs. Coxale with spinous dorsal bristle. Basale with 3 long bristles near terminal margin (1 lateral, 1 medial, 1 ventral). Exopodite with 3 bristles (2 long, 1 short). Endopodite: 1st joint with 1 α-bristle with long proximal spines and 2 β-bristles; end joint with 8 or 9 bristles including 3 claws (2 long stout, 1 short, medial).

Fifth Limb (Figure 17a,k): Epipodial appendage with 42 bristles. Endite I with 2 bristles; endite II and 3 or 4 bristles; endite III with numerous bristles. Exopodite: 1st joint with main tooth with 2 stout teeth, bristles of 1st joint obscure on specimen examined; 2nd joint consisting of large squarish tooth; 3rd joint with 2 short spinous bristles on outer lobe and 3 bristles on inner lobe; 4th and 5th joints fused, with total of 5 bristles.

Sixth Limb (Figure 17b): Endite I obscure on specimen examined but with at least 1 bristle; endite II with 3 bristles; endites III and IV each with 5 bristles; end joint not projecting posteriorly, with 6 spinous anteroventral bristles separated by space from 2 posterior hirsute bristles; 1 short bristle in place of epipodial bristle.

Seventh Limb (Figure 17c): 2 bristles in proximal group with 1 on each side; 4 bristles in distal group; each bristle with up to 4 bells and distal marginal spines; terminal comb with 6 recurved teeth opposite 4 or 5 recurved alate pegs.

Furca (Figure 17d): Each lamella with 6 claws: claws 1, 2, and 4 stout; claws 3, 5, and 6 short, slender; claw 1 with teeth forming medial and lateral row, distal teeth larger than others; claws 2 and 4 with teeth along posterior margins; claws 3, 5, and 6 with very slender spinelike teeth along posterior margins, and also with spines along distal anterior margins; margin of lamella between claws 4 and 5, 5 and 6, and following claw 6, hirsute; anterior margin of lamella with few hairs.

Rod-shaped Organ (Figure 17e): Elongate, with 4 or 5 weak proximal sutures, tip rounded.

Eyes: Medial eye pigmented, bare (Figure 17e); lateral eyes small, faint, unpigmented, with 4 ommatidia (Figure 17f).

Posterior of Body (Figure 17h): Dorsum evenly rounded with faint hairs forming row.

Y-Sclerite (Figure 17h): Typical for family.

Genitalia (Figure 17g): Sclerotized oval on each side proximal and anterior to furca.

Brushlike Organ (Figure 17g): Consisting of 5 minute bristles proximal to genitalia.

Eggs: USNM 156694 with 5; USNM 156695 with 6; USNM 156696 with 2 larvae and 5 empty egg sheaths.

Parasites: Carapace of USNM 156694 with stalked protistans (Plate 7a,e).

COMPARISONS.—The carapace of H. mayeri differs from that of H. bradmyersi in lacking lateral ribs. The rostral infold of H. mayeri bears 7–8 bristles compared to only 4 on H. paucichelatus. The terminal bristle on the endopodite of the 2nd antenna of the adult female of H. mayeri is on a minute 3rd joint not present on H. paucichelatus.