Parasterope lux Kornicker ex Kornicker & Poore 1996

Parasterope lux Kornicker

ETYMOLOGY.—From the Latin lux (light).

HOLOTYPE.—NMV J36004, ovigerous female on slide and in alcohol.

TYPE LOCALITY.—Slope 32, 38°21.90′S, 149°20.00′E, Victoria, S of Point Hicks; depth 1000 m.

PARATYPES.—None.

DISTRIBUTION.—Slope 32, 1000 m.

DESCRIPTION OF ADULT FEMALE (Figure 61).—Carapace oval in lateral view; incisur just ventral to valve midheight (Figure 61a).

Infold: Rostral infold with about 16 bristles along list, about 115 bristles dorsal to list, and about 17 bristles between list and incisur, all bristles with single pointed tips. Anteroventral infold with about 75 bristles between list and valve edge. Narrow list, with anterior end ventral to incisur, continues along ventral margin then broadens along posteroventral corner of valve. Ventral infold with about 29 bristles forming row between list and valve edge (posterior bristle in row lies adjacent to anterior end of broad posteroventral list). Broad posteroventral list with 42 or 43 wide flat triangular diaphanous bristles with tubular pores at base; row of 19–21 bristles (not more than 1 bristle between each pair of diaphanous bristles, and no bristles between ventral 15–17 bristles) slightly closer to anterior edge of broad list than diaphanous bristles. Posteroventral infold between broad list and valve edge with 7 long bristles opposite ventral 18 or 19 diaphanous bristles of list.

Selvage: Narrow lamellar prolongation with long marginal hairs at inner end of ventral margin of incisur.

Vestment: Long spines on anterodorsal corner proximal to infold of dorsal end of rostrum.

Central Adductor Muscle Attachments: Each valve with about 17 oval attachments just anteroventral to midpoint (location shown in Figure 61a).

Carapace Size (length, height in mm): NMV J36004 (holotype), 1.97, 1.38. Height 70% of length.

First Antenna: Except for ventral spines of 3rd and 4th joints being more distinct (Figure 61b), and presence of minute lateral spines along distal edge of dorsal margin of 5th joint, limb similar to that of P. sequax.

Second Antenna: Protopodite and endopodite similar to those of P. sequax. Exopodite: Bristle of 3rd joint with about 8 fairly stout proximal spines on ventral margin; basal spines slightly larger than those of P. sequax (spine of 8th joint about length of 9th joint); lateral spine of 9th joint about length of joint; exopodite otherwise similar to that of P. sequax.

Mandible: Coxale endite: Small medial bristle at base of ventral branch (Figure 61c); dorsal branch broken off both limbs of holotype; ventral branch with spines forming 5 oblique rows and tip with 1 short and 2 longer slender spines. Basale endite with 4 end bristles, 1 dwarf bristle, glandular peg, and 3 triaenid bristles (1 proximal to peg, 2 distal) with 5 or 6 pairs of marginal spines excluding terminal pair. Basale: ventral margin with 1 triaenid bristle (with 4 or 5 pairs of marginal spines excluding terminal pair) adjacent to base of endite and proximal to U-shaped boss; dorsal margin with 2 long spinous terminal bristles (about same length); medial surface with few rows of spines at midheight. Exopodite about length of dorsal margin of 1st endopodial joint, hirsute distally, and with 2 small subterminal bristles. 1st and 3rd endopodial joints similar to those of P. sequax. 2nd endopodial joint: Medial surface with 3 cleaning bristles between b- and c-bristles and 5 or 6 adjacent to c-bristle; joint otherwise similar to that of P. sequax.

Maxilla (Figure 61d): Except for distal dorsal bristle of basale being about length of similarly placed bristle on P. sequax, limbs similar (lateral bristle not observed) (Figure 61l,m). Left limb only of holotype with minute spine-like bristle proximal to alpha-bristle of 1st endopodial joint (Figure 61d).

Fifth Limb: Comb similar to that of P. sequax.

Sixth Limb: Posteroventral margin of skirt with 23 or 24 bristles; limb otherwise similar to that of P. sequax.

Seventh Limb: Each limb with 17 bristles (4 on terminal segment (2 on each side), 2 on next segment (1 on each side), 11 on proximal segments (5 or 6 on each side)); each bristle with 3 or 4 bells. Combs forming acute angle with each other (similar to that of P. sequax); each comb with 12–15 spinous teeth.

Furca: Each lamella with 9 claws (posterior 1 or 2 claws bristle-like, recurved); claws 1–7 with long slender teeth between more numerous smaller teeth (similar to those of P. sequax).

Bellonci Organ (Figure 61e): Similar to that of p. sequax.

Eyes: Medial eye hirsute with brownish pigment along center line and amber-colored cells along edges (Figure 61e,g). Lateral eye small but distinctly visible, with 4 large and 1 smaller ommatidia, and with brownish pigment between ommatidia (Figure 61h,i); eye visible through shell (Figure 61a).

Lips (Figure 61j): Upper lip with 3 small anterior spines on each lobe and 2 minute anterior spines on saddle between lobes. Lower lip a lateral hirsute flap on each side of mouth.

Genitalia, Posterior of Body (Figure 61k), Y-Sclerite (Figure 61k), and Gills: Similar to those of P. sequax.

Eggs: Holotype with 14 eggs in marsupium (some eggs visible in Figure 61a). Length of typical egg 0.41 mm.

COMPARISONS.—The main difference between P. lux and P. sequax is in the lateral eye. The lateral eyes of both species are small, but the eye of P. sequax is indistinct and was not seen with certainty on specimens examined, whereas the eye of P. lux is distinct and easily visible through the shell. Another difference is that the distal dorsal bristle on the basale of the maxilla of P. sequax (Figure 61m) is about twice as long as that of P. lux (Figure 61l).