Asteropella slatteryi Kornicker 1981

Asteropella slatteryi

Asteropella species.—Tuel, et al., 1976:141.

ETYMOLOGY.—The species is named for the collector Peter N. Slattery, Moss Landing Marine Laboratories.

HOLOTYPE.—USNM 141554, 1 ovigerous female on slides and in alcohol.

TYPE-LOCALITY.—Northern part of Monterey Bay, California, sta 1159, 3 May 1972.

PARATYPES.—Northern part of Monterey Bay: Sta 1105, depth about 15 m: USNM 156731, 1 juvenile, 10 Nov 1971. Sta 1152, depth about 33 m: USNM 156726, 156727, 2 ovigerous females, 24 Nov 1971; USNM 156746, 1 ovigerous female, 1 juvenile, 17 Nov 1972; USNM 156748, 1 ovigerous female, 23 Aug 1972. Sta 1153, depth about 9 m: USNM 156770, 1 juvenile, 10 May 1972. Sta 1156, depth about 35 m: USNM 156728, 1 A-1 female, 10 Nov 1971. Sta 1158, depth about 24 m: USNM 156751, 1 ovigerous female, 2 Feb 1972. Sta 1159, depth about 11 m: USNM 156725, 1 A-2 female, USNM 156730, 1 juvenile, 20 Aug 1971; USNM 156724, 156729, 2 ovigerous females, USNM 156732, 2 ovigerous females, 10 Nov 1971; USNM 156745, 1 ovigerous female, 1 adult female, 2 Feb 1972; USNM 156768, 156769, 2 juveniles, 3 May 1972. Sta 1175, depth about 35 m:USNM 141553, 1 ovigerous female, USNM 156723, 1 A-1 female, 21 Aug 1971; USNM 156750, 156771, 2 ovigerous females, 3 Feb, 1972; USNM 156747, 1 ovigerous female, 2 juveniles, 11 May 1972; USNM 156748, 1 ovigerous female, 23 Aug 1972. Sta A-3: USNM 143759, 1 ovigerous female, 11 Feb 1971 (sta A-3, Monterey Bay, California, from bottom in kelp bed off Monterey Beach; collector, E. C. Haderlie). Half Moon Bay, California: Sta 1C, June: USNM 156807, 11 specimens. Sta 5C, June: USNM 156803: 5 specimens. Sta 1A, Sept: USNM 156808, 33 specimens; USNM 156809, 1 ovigerous female. Sta 1B, Sept: USNM 156804, 27 specimens. Sta 1A, Dec: USNM 156810, 32 specimens. Sta 1B, Dec: USNM 156805, 22 specimens: USNM 156806, 1 adult male. Sta 1C, Sept: USNM 156802, 22 specimens.

DISTRIBUTION (Figure 90).—Monterey Bay and Half Moon Bay, California. Depth 6–37 m.

DESCRIPTION OF ADULT FEMALE (Figures 114–116, Plates 102, 103).—Carapace oval in lateral view (Figure 114, Plate 102a); dorsal margin convex or fairly flat, ventral margin evenly convex; small incisur forming almost right-angle just below middle of anterior margin (Plate 102i); narrow outer peripheral ridge just within valve edge parallels valve margin (Plate 102a–c); inner concentric ridge also parallels valve margin except in posterodorsal corner where it is flat or slightly concave, not convex like margin (Plate 102a,b); horizontal ridge at valve middle intersecting concentric ridge near incisur (Plate 102i), but not reaching concentric ridge posteriorly; horizontal rib not becoming wider in vicinity of central adductor muscle attachments (Plate 102a).

Ornamentation: With peripheral concentric, and horizontal ridges described above; ridges consisting of 1 or 2 rows of rectangular fossae (Plate 102c,i,l); a single row of rectangular-to-oval fossae present on either side of ridges; surface of valve with oval fossae (Plate 102g,h) covered over most of specimen examined by coating through which only few fossae are visible (Plate 102c,d,i); single bristles with pore near base emerging from unrimmed pores (Plate 102j) or rimmed pores (Plate 102e), some pores touching each other to form paired bristles (Plate 102f); bristles present along anterior and ventral margins and scattered over valve surface.

Infold (Plate 103a–c,h–l): Anterodorsal infold above incisur with 23 bristles either single or in pairs; infold immediately below rostrum with 2 long bristles; narrow list present from point ventral to the 2 bristles below rostrum to point near posterior margin; about 18 minute bristles along ventral margin just outside list; posteroventral list broad, with about 7 pairs of long bristles and about 10 additional smaller bristles (Plate 103h–l); a single row of 5 long bristles present between broad list and posterior edge of valve.

Central Adductor Muscle Attachment Scars: Consisting of about 12 individual oval scars in vicinity of horizontal ridge, with most scars being ventral to ridge. Attachments of muscle to shell shown in Plate 103a,f,g.

Selvage: Broad lamellar prolongation present on selvage along free margin, fringed along ventral margin (Plate 103b–e).

Size: USNM 141554, length 1.87 mm, height 1.39 mm, width 1.16 mm; USNM 156724, length 1.94 mm, height 1.38 mm; USNM 156726, length 1.94 mm, height 1.45 mm; USNM 156727, length 1.92 mm, height 1.42 mm; USNM 156729, length 1.92 mm, height 1.42 mm; USNM 156732, 2 specimens, length 1.91 mm, height 1.42 mm, length 1.85 mm, height 1.31 mm; USNM 141553, length 1.97 mm, height 1.42 mm.

First Antenna (Figure 115a): Lateral and medial surfaces of 1st joint hirsute; 2nd joint with few proximal dorsal hairs, 5 spinous bristles near middle of dorsal margin, and hairs along ventral margin; 3rd joint triangular, with 1 spinous midbristle and 4 spinous subterminal bristles on dorsal margin, and 1 long spinous bristle on ventral margin; 3rd and 4th joints combine to form rectangle; 4th joint with 3 spinous bristles (1 dorsal, 2 ventral); sensory bristle of long 5th joint with 1 or 2 minute proximal filaments (not shown in illustrated limb) and forming 2 distal branches, each branch with bifurcate tip; medial bristle of 6th joint long, about equal in length to combined 3rd-8th joints; lateral side of 6th joint with few hairs. Seventh joint: a-claw about equal in length to combined 5th-8th joints, bare; b-bristle about same length as sensory bristle of 5th joint, bare except for minute filament near tip; c-bristle slightly longer than sensory bristle, with 1 or 2 minute proximal filaments and 1 near tip. Eighth joint: d-bristle absent; e-bristle bare with blunt tip reaching tip of a-claw, or slightly longer than a-claw; f-bristle bent dorsally, about same length as b-bristle, with 1 minute filament proximal and 1 near tip; g-bristle same length as c-bristle, with 1 minute filament proximal and 1 near tip.

Second Antenna (Figure 115b): Protopodite with fairly long, spinous, medial bristle, otherwise bare. Endopodite 3-jointed: 1st joint short, bare; 2nd joint elongate, hirsute; 3rd joint very long, hirsute, with terminal bristle with few marginal spines. Exopodite: 1st joint elongate with short, recurved, medial bristle on distal margin; bristles of joints 2–3 (possibly also 4 and 5) with faint slender spines along middle of ventral margin; bristles of joints 2–8 with natatory hairs; 9th joint with 3 bristles (2 long, 1 medium), all with natatory hairs; usual row of spines not observed along distal margins of joints; basal spines absent.

Mandible (Figure 115c): Coxale endite: minute bristle present at base of ventral branch; ventral branch with spines forming 5 oblique rows; tip of branch with 3 minute teeth; ventral margin of endite proximal to ventral branch, hirsute and with glandular field; medial side of dorsal branch with 5 minute teeth near tip of ventral branch; ventral margin of dorsal branch with 2 small acute nodes followed by 2 larger more rounded nodes; main spine with few marginal spines; longer spines on endite near base of main spine; spines present on margin of endite between main spine and tip of endite; protracted tip with marginal spines; long, hirsute, posterior bristle with base near tip of endite; dorsal margin of endite with few distal serrations. Basale: tip of endite with 4 bristles: 1 long with short marginal teeth, 1 short with short marginal teeth, and 2 triaenid bristles with 4 pairs of widely spaced teeth followed by 1 pair of very long teeth followed by about 16 pairs of small teeth excluding minute triaenid tip; 1 dwarf bristle and 1 triaenid bristle near proximal end of endite; ventral margin of basale with 3–5 triaenid bristles with 5–8 pairs of widely spaced proximal teeth followed by 1 pair of very long teeth followed by 9–11 pairs of small teeth (excluding terminal pair), the latter teeth decreasing in length distally along bristle; dorsal margin of basale with 2 long terminal bristles with short marginal spines. Exopodite about two-thirds length of 1st endopodial joint, with marginal hairs forming 2 rows, and 2 terminal bristles almost reaching middle of 2nd endopodial joint. Endopodite: 1st joint with 6 spinous ventral bristles (2 stout with long marginal spines, 4 slender with short marginal spines); ventral margin of 2nd joint with 2 spinous bristles (lateral of these slender, other stout); dorsal margin of 2nd joint with 10 bristles, most with short marginal spines; medial surface of 2nd joint with 5 distal, spinous, cleaning bristles, and long hairs forming rows; end joint with 3 stout, bare, clawlike bristles (dorsal of these about one-half length of others and with few widely spaced faint spines), 1 long lateral bristle with few short marginal spines, and 1 short ventral bristle.

Maxilla (Figure 116a): Epipodite with hairs ventrally in proximal half and pointed tip reaching past middle of basale. Endites not distinctly separated, consisting of 6 long bristles with distal spines, and 1 minute bristle. Basale: dorsal margin with proximal hairs and 1 bare distal bristle; medial surface hirsute near the ventral margin and with 1 short proximal bristle; ventral margin with 1 long, spinous, terminal bristle and 1 minute distal bristle; lateral side with 1 proximal bristle. Exopodite not present. Endopodite: 1st joint with few distal hairs and long spinous beta-bristle; 2nd joint with 4 spinous bristles (3 long, 1 short).

Fifth Limb (Figure 116b): Dorsal margin of comb with long hairs near distal end, none of these hairs stouter than others; lateral side of comb with long proximal bristle near ventral margin, 2 short slender bristles just distal to its base, 3 short bristles along middle part close to ventral margin, and 1 long spinous bristle with base near dorsal margin; latter bristle not reaching end of comb; ventral margin of comb with 40 short spinous bristles, and with hairs along medial side.

Sixth Limb (Figure 116c): Protopodite (trunk) with single row of 20 short spinous bristles along anterior margin with bases on medial side; 4 short, spinous, medial bristles of same type present near middle of protopodite, with bases just posterior to anterior row; 2 longer, spinous, medial bristles present near anterior margin proximal to suture separating protopodite from wide skirt; broad lateral flap with 9 spinous bristles; anteroventral margin of skirt with 22–24 spinous bristles; posterior end of skirt prolonged, with 1 short hirsute bristle; limb hirsute, no epipodial bristles.

Seventh Limb (Figure 116d): Broad at base then becoming narrower to point near middle where it broadens to about width of base; broad part with 32–39 bristles, about an equal number on each side; each bristle with up to 7 bells; most segments of limb with 2 bristles, 1 on each side; terminus with 10 or 11 recurved spinous teeth.

Furca (Figure 116e): Each lamella with 8 claws; claws 1–3 primary with lateral and medial row of teeth along proximal two-thirds, proximal teeth longer than distal teeth; secondary claws about same length but decreasing in width distally along lamella; claws 4–7 with spines along posterior margin; claw 8 bare or with few spines, with base set slightly back from edge of lamella; all secondary claws without rings and more-or-less equally spaced along lamella; medial hairs forming clusters near anterior margin of lamella.

Rod-shaped Organ (Figures 115d, 116f): 3-jointed: 1st joint broad with faint spines; middle part short flaring; distal part tapering distally to rounded tip.

Eyes: Medial eye bare, pigmented (Figures 115d, 116f). Lateral eye small, pigmented, with about 4 small, indistinct ommatidia (Figure 115d).

Upper Lip (Figures 115d, 116i): Consisting of 2 hirsute lobes, each with anterior spinous process (anterior process absent in Figure 115d); hirsute lateral flap on each side of mouth; saddle between lobes with 4 minute anterior spines.

Posterior of Body (Figure 116g): With elongate dorsal process with long spines at tip.

Y-Sclerite (Figure 116h): Slightly sinuate at posterior end, tapering anteriorly without ventral branch.

Eggs: USNM 141554 with 11 eggs; USNM 156729 with 12 eggs; USNM 156724 with 12 eggs; USNM 156729 with 11 eggs.

DESCRIPTION OF ADULT MALE (Figure 117).—Carapace similar to that of adult female except posterodorsal corner of inner concentric ridge with distinct concavity (Figure 117a).

Central Adductor Muscle Attachment Scars: Consisting of about 14 individual oval scars in vicinity of horizontal midridge; most scars ventral to midridge.

Size: USNM 156806, length 1.34 mm, height 0.91 mm.

First Antenna (Figure 117b): Lateral and medial surfaces of 1st joint hirsute; 2nd joint with proximal dorsal hairs, 4 spinous bristles near middle of dorsal margin, and hairs along ventral margin; 3rd joint triangular, with 1 spinous midbristle and 3 spinous subterminal bristles on dorsal margin, and 1 long spinous bristle on ventral margin; 3rd and 4th joints combine to form rectangle; 4th joint with 2 spinous bristles (1 ventral, 1 dorsal); 5th joint shorter than that of female; sensory bristle of 5th joint with stout trunklike proximal part, 10 long filaments near middle, and stem forming 2 distal branches, each branch with bifurcate tip; 6th joint longer than that of female; medial bristle of 6th joint long, about equal in length to combined 3rd-8th joints, with short marginal spines. Seventh joint: a-claw about equal in length to combined lengths of 5th-8th joints, bare; b-bristle reaching tip of sensory bristle of 5th joint, with 3 fairly long proximal filaments and bifurcate tip; c-bristle slightly longer than b-bristle, with 4 fairly long proximal filaments and 1 shorter filament near tip. Eighth joint: d-bristle absent; e-bristle bare with blunt tip reaching just past tip of a-claw; f-bristle not bent dorsally, about same length as b-bristle, with 4 fairly long proximal filaments and 1 shorter filament near tip; g-bristle about same length as c-bristle, with 4 fairly long proximal filaments and 1 shorter filament near tip.

Second Antenna (Figure 117c): Protopodite and exopodite similar to that of adult female except 9th joint of exopodite with only 2 bristles. Endopodite 3-jointed; 1st joint elongate, bare; 2nd joint very long, with 2 short distal bristles; 3rd joint short, with long proximal bristle and short, recurved, terminal claw.

Mandible: Coxale endite similar to that of adult female. Basale: endite similar to that of adult female except triaenid bristles with up to 6 pairs of marginal teeth proximal to pair of long teeth and 10 or 11 pairs of teeth (excluding terminal pair) following paired long teeth; ventral margin of basale with 4 triaenid bristles similar to those of adult female; dorsal margin of basale with 2 long terminal bristles with short marginal spines. Exopodite similar to that of adult female, outer bristle longer than inner bristle. Endopodite: ventral margin of 1st joint with 5 bristles (2 with long marginal spines, 3 with short marginal spines); ventral margin of 2nd joint with 2 spinous terminal bristles (lateral of these shorter and more slender than medial bristle); dorsal margin of 2nd joint with 9 bristles, bare or with short, faint, marginal spines; medial surface of 2nd joint with 5 distal, spinous, cleaning bristles, and long hairs forming rows; end joint similar to that of adult female.

Maxilla: Similar to that of adult female.

Fifth Limb (Figure 117d): Similar to that of adult female but with additional small ventral bristle proximal to long exopodial bristle.

Sixth Limb: Bristles not counted, but limb similar to that of adult female.

Seventh Limb: One limb with 22 bristles, 10 or 11 on each side; other limb with 12 bristles on one side and many missing bristles on other side; terminus with 6 or 7 recurved spinous teeth.

Furca (Figure 117e): Each lamella with 7 claws; claws 1–3 primary, claws 4–6 secondary, claw 8 bristlelike with base set back from edge of lamella; teeth on claws similar to those of adult female.

Rod-shaped Organ, Eyes (Figure 117f), Posterior of Body and Y-Sclerite (Figure 117g): Similar to those of adult female.

Upper Lip (Figure 117h): Consisting of 2 hirsute lateral lobes, each with spinous anterior process; anterior of medial saddle with 4 minute anterior spines proximal to anterior process of lateral lobe; hirsute lateral flap on each side of mouth.

Copulatory Appendage: Small, consisting of short lobes on both sides of body.

DESCRIPTION OF A-1 FEMALE (Figure 118a,b).—Carapace similar to that of adult female with exception of posterodorsal corner of concentric ridge being deeply concave, rather than flat or slightly concave (Figure 118a).

Size: USNM 156723, length 1.66 mm, height 1.25 mm; USNM 156728, length 1.63 mm, height 1.29 mm.

Seventh Limb: Limb with 37 strongly tapering bristles, 21 on 1 side, 16 on other; terminus with recurved comb teeth.

Furca: Each lamella with 7 claws: 3 long primary claws, 3 short secondary claws, and 1 slender, unringed, bristlelike claw; the space between claws 6 and 7 about the same, or slightly wider than space between claws 5 and 6.

Lateral Eye (Figure 118b): Small with about 4 ommatidia, pigmented brown.

DESCRIPTION OF A-2 FEMALE (Figure 118c–e).—Carapace similar to that of A-l female (Figure 118c).

Central Adductor Muscle Attachment Scars (Figure 118d): Consisting of about 16 individual oval scars in vicinity of horizontal midrige.

Size: USNM 156725, length 1.22 mm, height 0.88 mm.

First Antenna: Sensory bristle of 5th joint similar to that of adult female but minute proximal filaments not observed; e-bristle of 8th joint slightly longer than a-claw of 7th joint.

Second Antenna (Figure 118e): Endopodite similar to that of adult female, hairs not observed.

Sixth Limb: With many bristles.

Seventh Limb: With 18 tapering bristles, 9 on each side.

Furca: Each limb with 3 primary and 3 secondary claws.

Lateral Eye: Similar to that of A-l female.

Posterior of Body: Elongate dorsal process similar to that of A-l female and adult female.

ONTOGENY.—Juvenile carapaces differ from those of adult in having deeper concavity in posterodorsal corner of concentric ridge. Bristles of 7th limbs of juveniles tapered, not cylindrical as on adult; 7th limb of A-2 female with fewer bristles than 7th limbs of both A-l female and adult female. The number of furcal claws increases by 1 at each stage of development: A-2 female – 6 claws; A-l female – 7 claws; adult female – 8 claws.

COMPARISONS.—The carapace of the new species, A.slatteryi, differs from that of A.scammonensis and A. trithrix in being larger and in having a flat or slightly concave posterodorsal corner on the inner concentric ridge. The endopodite of the 2nd antenna of the female A. slatteryi differs from that of A. trithrix in lacking bristles on the 2nd joint. The dorsal margin of the mandibular basale of A. slatteryi bears 2 bristles compared to 3 on A. trithrix. The 7th limb of A. slatteryi bears more bristles than are present on the 7th limbs of A. scammonensis or A. trithrix. Some appendages of A. slatteryi are compared with those of other species of Asteropella from the eastern Pacific in Table 24.