Scleroconcha pix Kornicker 1996

Scleroconcha pix

ETYMOLOGY.—From the Latin pix (pitch).

HOLOTYPE.—Partly dissected adult female in alcohol, QM W20740.

TYPE LOCALITY.—Calliope River and Auckland Creek area, near Gladstone, Queensland, Australia.

PARATYPES.—Type locality: USNM 157968A, ovigerous female on slide and in alcohol; USNM 194281, ovigerous female with female choniostomatid in marsupium; USNM 194282, 3 ovigerous females; USNM 194283, 9 adult females including 1 with parasite eggs and 1 or 2 with ostracode eggs; USNM 194284, ovigerous female with female choniostomatid in marsupium.

DISTRIBUTION.—Known only from type locality.

DESCRIPTION OF ADULT FEMALE (Figures 10–12).—Carapace oval in lateral view with prominent rostrum and small projecting caudal process (Figure 10).

Ornamentation (Figure 10): Lateral surface with a narrow rib just within ventral and dorsal margins and with 2 narrow lateral ribs: upper rib terminating anteriorly in small process on rostrum extending past valve edge (Figure 10); lower rib terminating anteriorly at short vertical ridge ventral to incisur; both ribs terminating posteriorly on caudal process. Central adductor muscle attachments intersect lower lateral rib anterior to valve midlength. Surface of valve with abundant shallow fossae (filled with debris in specimens examined). Undivided bristles, some with broad bases, sparsely distributed over valve surface, more numerous along anterior and ventral margins; 12–14 short bristles along outer edge of caudal process and with bases on outer surface of valve (Figure 11b). Minute papillae covering valve surface between fossae, visible along ventral edge of valve viewed from inside.

Infold: Rostral infold with 10 bristles (Figure 11a); 2 indistinct flat unringed bristles at inner end of incisur, 1 small bristle present ventral to inner end of incisur; anteroventral infold with about 12 ridges and with 5 bristles forming row parallel to valve edge; infold along middle of ventral margin bare; posterior end of ventral infold and posterior infold in vicinity of caudal process with numerous small bristles; infold of caudal process with narrow flap bearing 4 or 5 bristles with well-defined sockets and several less well-defined bristles without well-defined sockets (Figure 11b); 1 small bristle present between flap and valve edge.

Selvage: Broad lamellar prolongation with marginal fringe present along anterodorsal, anterior, and ventral margins of valve; lamellar prolongation narrower and with minute fringe along posterior edge of valve; prolongation absent in vicinity of row of 12–14 short bristles along outer edge of caudal process. Selvage divided at inner edge of incisur (prolongation along dorsal edge of incisur overlaps prolongation along ventral margin).

Carapace Size (length (L), height (H), in mm): QM W20740 (holotype), L=1.66, H =1.11. USNM 157968A, L= 1.64, H =1.15. USNM 194281, L = 1.46, H = 0.98. USNM 194282, 3 ovigerous females: L=1.62, H =1.10; L=1.64, H = 1.08; L = 1.63, H = 1.09. USNM 194284, L = 1.68, H = 1.11.

First Antenna (Figure 11e,f): 1st joint with rows of indistinct spines along dorsal margin. 2nd joint spinous (dorsal margin with long proximal spines; ventral margin with short spines; lateral surface with row of short spines along distal edge near dorsal margin) and with 3 bristles (1 ventral, 1 dorsal, 1 lateral). Short 3rd joint with 3 bristles (1 ventral, 2 dorsal). 4th joint spinous and with 5 bristles (3 ventral, 2 dorsal). 5th and 6th joints fused, with row of short lateral spines along distal edge; sensory bristle of 5th joint with 7 short proximal filaments, a cluster of 3 subterminal filaments, and bifurcate tip; 6th joint with medial bristle with long proximal spines. 7th joint: a-bristle same length as bristle of 6th joint, with proximal wreaths of long spines and distal short spines; b-bristle almost twice length of a-bristle, with 2 short proximal filaments, 2 short subterminal paired filaments, and bifurcate tip; c-bristle slightly longer than bristle of 5th joint, with 7 short proximal filaments, a cluster of 3 short subterminal filaments, and bifurcate tip. 8th joint: d- and e-bristles same length as bristle of 5th joint, bare with blunt tips; f-bristle about same length as c-bristle, with 7 short proximal filaments, a cluster of 3 distal filaments, and bifurcate tip; g-bristle same length as c-bristle, with 6 short proximal filaments, a cluster of 3 distal filaments, and bifurcate tip.

Second Antenna: Protopodite bare (Figure 11g). Endopodite 2-jointed (Figure 11g): 1st joint short, with 5 proximal bristles and 1 distal bristle; 2nd joint only slightly longer than 1st, with 1 long spinous proximal bristle and 1 short bare terminal bristle. Exopodite: 1st joint with minute terminal medial tubular bristle; bristles of joints 2–4 about length of bristle of 5th joint, bare; bristles of joints 5–8 unbroken, with natatory hairs; 9th joint with 7 unbroken bristles (3 long, 1 medium, 2 short, all with natatory hairs, 1 very short with few short spines); joints 2–8 with slender spines along distal edges; joints 2 and 3 with 2 minute basal spines; joints 4–8 with single longer basal spine increasing in size on distal joints (spine of 8th joint to length of ventral margin of joint 9).

Mandible (Figure 12a,b): Coxale with long and short medial spines; endite bifurcate, with long proximal spines and few short distal teeth; minute bristle near base of endite. Basale: dorsal margin with 3 long spinous bristles (1 at distal , 2 terminal); medial surface hirsute, with 5 or 6 bristles (3 or 4 pectinate unringed; 2 ringed, with long proximal and short distal spines) in proximal ventral corner and 1 ringed spinous bristle close to middle of joint; ventral margin with 8 spinous bristles. Exopodite hirsute distally, length about length of dorsal margin on 1st endopodial joint, with 2 bristles bearing wreaths of long spines (distal outer bristle about length of inner bristle). 1st endopodial joint with 4 ventral bristles bearing wreaths of long spines; medial surface with rows of short spines. 2nd endopodial joint: ventral margin with ringed bristles forming 2 distal groups (3 bristles in each group); dorsal margin with 10 bristles near midlength, some with bases on medial and lateral sides of joint; medial surface and proximal ventral and dorsal margins spinous. 3rd endopodial joint with 3 claws with indistinct proximal ventral teeth (dorsal claw about length of medial ventral claw; medial ventral claw about length of lateral ventral claw), and 4 ringed bristles.

Maxilla (Figure 12c,d): Endite I with 10 or 11 spinous and pectinate bristles; endites II and III narrow, with terminal bristles; endite III also with 1 proximal lateral bristle. Coxale with medial hairs along dorsal surface and plumose dorsal bristle. Basale with 3 bristles along distal margin (dorsal bristle short). Exopodite with 3 spinous bristles. 1st endopodial joint with rows of short spines and long hairs, 1 spinous alpha-bristle, and 5 beta-bristles (bare or with short spines). End joint with 3 ringed a-bristles, 2 b-bristles (1 ringed and bearing small spines, 1 stout unringed claw-like, with few small teeth), 2 small ringed spinous c-bristles, and 3 d-bristles (2 stout unringed claw-like with few indistinct teeth, 1 long ringed and posterior).

Fifth Limb (Figure 12e,f): Endite I with about 5 spinous and pectinate bristles; endite II with about 7 spinous and pectinate bristles; endite III with about 9 spinous and pectinate bristles. 1st exopodial joint: anterior margin with 2 spinous bristles along distal edge at midwidth, and 1 bristle on small lobe near outer edge (Figure 12e); main tooth with 4 cusps (3 pectinate cusps and 1 proximal smooth pointed cusp) (Figure 12e,f); distal cusp with pointed cusp at base (Figure 12e,f); 1 spinous ringed bristle proximal to main tooth. 2nd exopodial joint: large tooth with 2 small adjacent teeth (proximal tooth pointed, distal tooth rounded) along inner margin (Figure 12f); distal outer comer of large tooth with minute bristle; long proximal posterior c-bristle bare; 3 posterior bristles in row, with outer bristle short and separated by space from middle bristle; inner bristle about length of middle bristle, all bare (Figure 12f). 3rd endopodial joint: inner lobe with 3 bristles; outer lobe with 2 bristles. 4th and 5th joints fused, hirsute, with total of 6 spinous bristles (Figure 12f).

Sixth Limb (Figure 11h): Endite I with 3 spinous bristles; endite II with 1 proximal and 3 terminal spinous bristles; endite III with 1 proximal, 1 subterminal, and 7 or 8 terminal spinous bristles; endite IV with 1 subterminal and 6 terminal spinous bristles. End joint with total of 22 spinous and plumose bristles. Four epipodial bristles with long proximal hairs.

Seventh Limb: Each limb with 10 bristles, 4 in proximal group, 2 on each side, each with 3 or 4 bells (mostly 3); 6 in terminal group, 3 on each side, each with 2–7 bells; all bristles with marginal spines. Terminus with comb of 4 small indistinct teeth and without peg opposite comb (Figure 12g).

Furca (Figures 11e,f, 12h): Each lamella with 10 or 11 claws, all articulated. Claw 3 about length of 4th claw and much thinner (Figure 11c,i) (small claw absent on right lamella of USNM 157968A, aberrant? (Figure 12h)); claws 4 to 10 or 11 decreasing in length and width posteriorly along lamella; all claws with teeth along posterior margin; claw 1 with medial row of teeth stouter near claw midlength. Right lamella with short medial rows of hairs near anterior edge, anterior to left lamella by width of base of claw 1; hairs present medially at bases of some claws. (Teeth and hairs not shown.)

Bellonci Organ (Figure 12i): Elongate with about 17 sutures; minute spines along many sutures (spines became visible under oil immersion (× 15 ocular, × 100 objective)); tip pointed with minute terminal spine.

Eyes: Medial eye bare with brown pigment (Figure 12i). Lateral eye minute, indistinct, and with 2 small ommatidia (Figure 12j).

Upper Lip (Figure 12i): Normal for genus.

Anterior of Body (Figure 12i): Small rounded process between upper lip and medial eye.

Posterior of Body: Bare.

Y-Sclerite (Figure 11d): Normal for genus.

Number of Eggs: USNM 157968A with 12 eggs in marsupium and with smaller unextruded eggs; length of 1 extruded egg 0.21 mm. USNM 194281 with 3 eggs in marsupium (a female choniostomatid also present); length of 1 egg including transparent sheath 0.25 mm, without transparent sheath 0.19 mm. USNM 194284 with 6 eggs in marsupium (a female choniostomatid also present); length of 1 well-developed egg 0.21 mm.

Parasites: USNM 194281 with female choniostomatid and 3 ostracode eggs in marsupium. USNM 194283, marsupium of a torn adult female S. pix with pear-shaped egg case (choniostomatid?) with about 50 eggs (length of 1 egg 0.09 mm); egg case with short stem (attachment?) at narrow end (narrow end folded over); egg case length 0.54 mm (would be longer (about 0.80 mm) if folded part included), maximum width 0.36 mm. USNM 194284 with female choniostomatid and 6 ostracode eggs in marsupium.

COMPARISONS.—Scleroconcha pix differs from previously described species of the genus in the small size of the third furcal claw, which is about one-third the length of the fourth claw, compared to the third and fourth claws being about the same length in other species.

RUTIDERMATIDAE Brady and Norman, 1896

COMPOSITION.—The Rutidermatidae includes two subfamilies: Rutidermatinae Brady and Norman, 1896, and Metaschismatinae Kornicker, 1994. Both subfamilies have been collected in the vicinity of Australia.

RUTIDERMATINAE Brady and Norman, 1896

COMPOSITION.—This subfamily includes three genera: Rutiderma Brady and Norman, 1896, Alternochelata Kornicker, 1958, and Scleraner Kornicker, 1975. All have been reported in the vicinity of Australia.

DISTRIBUTION.—Widespread on continental shelves, except in the Arctic and Antarctic, and sparse on continental slopes. Known depth range is intertidal to 1834 m.

Rutiderma Brady and Norman, 1896

TYPE SPECIES.—Rutiderma compressa Brady and Norman, 1896.

COMPOSITION.—This genus has 28 species, including three new species described herein.

DISTRIBUTION.—Widespread between the latitudes 45°N and 53°S, intertidal to 317 m, but questionably reported from 1834 m (Cohen and Kornicker, 1987:3). Poore et al. (1975:31, 60, 61) reported, but did not describe or illustrate, Rutiderma sp. among the fauna of Port Phillip Bay, Victoria, collected in bottom samples at depths of 20–24 m. Whether or not their species is conspecific with either of the two new species described below must await restudy of the Port Phillip Bay specimens.