Spinacopia trox Kornicker 1995

“Spinacopia trox, new species

Figures 33, 34

ETYMOLOGY.—From the Greek trox (nibbler, gnawer).

HOLOTYPE.—Ovigerous female in alcohol in collection of the Museum of Victoria.

TYPE LOCALITY.—Slope 1, 34°59.52'S, 151°5.94'E, New South Wales, off Nowra, depth 204 m.

PARATYPES.—Slope 1: USNM 193939, adult female with parasitic copepod and copepod egg sacs in marsupium, on slide and in alcohol.

DISTRIBUTION.—Slope 1,204 m.

DESCRIPTION OF ADULT FEMALE.— Carapace oval in lateral view, with projecting caudal process and with very slight indentation in anterior outline suggesting location of incisur, but no indentation in valve edge. Posterodorsal part of valve with prominent bulge with rounded posterior edge. Surface without gel-like coating.

Ornamentation: With prominent posterodorsal bulge (holds eggs in ovigerous female, and also copepod egg sacs). Long undivided bristles, most with broad base, very sparsely distributed on outer surface of valves; long and short undivided bristles, some with broad proximal half, fairly numerous along anterior and ventral valve margins. Outer surface with minute indistinct pustules; small round areas (with pustules more closely packed and slightly more distinct then surrounding pustules) fairly numerous over valve surface.

Infold: Anteroventral infold with small bristle near inner margin. Infold of caudal process with row of 8 or 9 spinous bristles on ridge anterior to pocket, 2 small bare bristles at ventral end of ridge, and several small bristles along inner margin of infold; 1 slender bare bristle on infold dorsal to caudal process at about 1/4 valve midheight measured from dorsal margin (not shown).

Selvage: Wide lamellar prolongation with smooth outer edge present along anterior, ventral, and posterior margins of valves.

Central Adductor Muscle Attachments: Comprising 17-19 ovoid attachments.

Carapace Size (length, height in mm): Holotype, 1.51, 1.30; USNM 193939, 1.52, 1.27.

First Antenna: 1st joint bare. 2nd joint with 1 spinous dorsal bristle and spines on ventral and dorsal margins and on lateral side near ventral margin. 3rd and 4th joints fused; small 3rd joint with 2 spinous bristles (1 dorsal, 1 ventral); long 4th joint with 2 bristles (1 ventral, 1 dorsal). Long 5th joint with long ventral bristle with row of minute spines near midlength. Minute 6th joint fused to 5th, with small spinous medial bristle. 7th joint: a-bristle spinous, about 4 times length of bristle of 6th joint; b-bristle almost twice length of a-bristle, bare except for spine at tip; c-bristle about same length as bristle of 5th joint, with row of minute spines near midlength and spine at tip. 8th joint: d- and e-bristles longer than b-bristle, bare with blunt tips; f-bristle about same length as e-bristle, with row of minute spines at distal 2/3 and with spine at tip; g-bristle about same length as bristle of 5th joint, bare except for spine at tip. Marginal spines of bristles of joints 2-4 and 6 indistinct, but visible at high magnification (xl5 ocular, xlOO objective).

Second Antenna: Protopodite bare (without long spines present on S. crux). Endopodite 2-jointed: 1st joint with 2 small proximal bristles and without medial spines present on S. crux; 2nd joint small with spinous terminal bristle about 1/3 longer than bristles of 1st joint. Exopodite: joint 1 with small recurved medial terminal bristle; bristles of joints 2-8 with stout proximal ventral spines and distal natatory hairs; 9th joint with 3 bristles (ventral with small proximal ventral spines and distal natatory hairs, middle short with small marginal spines, dorsal short bare and with base medial to middle bristle); joints 2-7 with row of minute spines along distal edges. USNM 193939 with some exopodial bristles broken (may have been broken during dissection).

Mandible: Coxale similar to that of S. crux. Basale: dorsal margin with small unringed spine-like bristle near midlength and 1 longer ringed spinous subterminal bristle; ventral margin with 7 bristles. Exopodite absent. 1st endopodial joint: dorsal margin with several slender terminal spines; ventral margin with minute spine at midlength, 2 stouter distal spines, and long terminal claw; medial surface with unringed spine-like bristle at base of ventral claw, and slender spines near distal edge. 2nd endopodial joint: dorsal margin with 2 fairly long unringed spine-like subterminal bristles; medial surface with few spines near base of stout ventral claw. 3rd endopodial joint with long terminal claw, 2 short unringed ventral bristles, and 1 minute subterminal unringed dorsal bristle.

Maxilla: Coxale with short dorsal bristle and fringe of long hairs. Endites I and HI with 6 bristles; endite II with 4 bristles. Basale with short bristle near exopodite. Exopodite with 2 unequal bristles. Endopodite similar to that of S. crux.

Fifth Limb: Similar to that of S. crux.

Sixth Limb: Endite I with 3 short spinous bristles; endite II with 2 long spinous bristles. End joint with 14 or 15 spinous bristles followed by 2 plumose posterior bristles (1 limb of USNM 193939 with only 1 plumose posterior bristle (aberrancy)).

Seventh Limb: Proximal group with 2 bristles, 1 on each side (1 on segment 9 and 1 on segment 10 counting from segment proximal to terminus), each with 5 bells; terminal group with 6 bristles, 3 on each side, each with 2-6 bells. Terminus with opposing combs, each with 9-12 elongate teeth with recurved bulbous tips; area between opposing combs mound-like.

Furca: Each lamella with 7 claws; claw 1 nonarticulated; claw 3 about 2/3 length of claw 4; all claws with teeth along posterior edges.

Bellonci Organ: Elongate, cylindrical, with 2 weak sutures near midlength, and triangular tip.

Eyes: Medial eye bare, with brown pigment. Lateral eye unpigmented, smaller than medial eye, with 4 ommatidia.

Genitalia: Oval ring on each side of body anterior to furca.

Upper Lip: Single hirsute lobe without stout anterior spines.

Posterior of Body: Evenly rounded, bare.

Y-Sclerite: With ventral branch.

Number of Eggs: Holotype with 7 eggs (4 in posterodorsal bulge of right valve, and 3 in left), length of 1 egg 0.31 mm. USNM 193939 with unextruded eggs (this specimen has choniostomatid copepod and copepod egg sacs in marsupium).

Parasites: USNM 193939 with 1 female choniostomatid copepod and 3 copepod egg sacs (1 containing spherical eggs, 2 containing pyriform eggs) in marsupium. Both the female copepod and its egg sac mimic the ostracode egg in size. A similar mimicry has been reported for copepods parasitizing the ostracode Parasterope pollex Kornicker (Bowman and Kornicker, 1967:1).

Ectozoa: USNM 193939 with round Foraminifera attached to outer surface of right valve near posterior end at midheight.

COMPARISONS.—Spinacopia trox is very close to S. crux. It differs in not having spines on either the protopodite or the 1st endopodial joint of the 2nd antenna, in having 9 or 10 rather than 2 or 3 teeth in the terminal combs of the 7th limb as well as a mound between combs, and in the carapace being much larger (length 1.51-1.52 mm compared to 1.10 mm for S. crux). The terminal bristle of the endopodite of the 2nd antenna is shorter on S. trox than on S. crux, but the variability of this character is not known.”

(Kornicker, 1995, pp. 54-57)

Spinacopia trox

ETYMOLOGY.—From the Greek trox (nibbler, gnawer).

HOLOTYPE.—Ovigerous female in alcohol in collection of the Museum of Victoria.

TYPE LOCALITY.—Slope 1, 34°59.52′S, 151°5.94′E, New South Wales, off Nowra, depth 204 m.

PARATYPES.—Slope 1: USNM 193939, adult female with parasitic copepod and copepod egg sacs in marsupium, on slide and in alcohol.

DISTRIBUTION.—Slope 1, 204 m.

DESCRIPTION OF ADULT FEMALE (Figures 33, 34).—Carapace oval in lateral view, with projecting caudal process and with very slight indentation in anterior outline suggesting location of incisur (Figure 33a,d), but no indentation in valve edge (Figure 33d). Posterodorsal part of valve with prominent bulge with rounded posterior edge (Figure 33b–d). Surface without gel-like coating.

Ornamentation: With prominent posterodorsal bulge (holds eggs in ovigerous female, and also copepod egg sacs (Figure 33c)). Long undivided bristles, most with broad base, very sparsely distributed on outer surface of valves; long and short undivided bristles, some with broad proximal half, fairly numerous along anterior and ventral valve margins (Figure 33e). Outer surface with minute indistinct pustules; small round areas (with pustules more closely packed and slightly more distinct then surrounding pustules) fairly numerous over valve surface.

Infold: Anteroventral infold with small bristle near inner margin (Figure 33d,e). Infold of caudal process with row of 8 or 9 spinous bristles on ridge anterior to pocket, 2 small bare bristles at ventral end of ridge, and several small bristles along inner margin of infold (Figure 33f); 1 slender bare bristle on infold dorsal to caudal process at about valve midheight measured from dorsal margin (not shown).

Selvage: Wide lamellar prolongation with smooth outer edge present along anterior, ventral, and posterior margins of valves.

Central Adductor Muscle Attachments (Figure 33a,c): Comprising 17–19 ovoid attachments.

Carapace Size (length, height in mm): Holotype, 1.51, 1.30; USNM 193939, 1.52, 1.27.

First Antenna (Figure 33g): 1st joint bare. 2nd joint with 1 spinous dorsal bristle and spines on ventral and dorsal margins and on lateral side near ventral margin. 3rd and 4th joints fused; small 3rd joint with 2 spinous bristles (1 dorsal, 1 ventral); long 4th joint with 2 bristles (1 ventral, 1 dorsal). Long 5th joint with long ventral bristle with row of minute spines near midlength. Minute 6th joint fused to 5th, with small spinous medial bristle. 7th joint: a-bristle spinous, about 4 times length of bristle of 6th joint; b-bristle almost twice length of a-bristle, bare except for spine at tip; c-bristle about same length as bristle of 5th joint, with row of minute spines near midlength and spine at tip. 8th joint: d- and e-bristles longer than b-bristle, bare with blunt tips; f-bristle about same length as e-bristle, with row of minute spines at distal and with spine at tip; g-bristle about same length as bristle of 5th joint, bare except for spine at tip. Marginal spines of bristles of joints 2–4 and 6 indistinct, but visible at high magnification (×15 ocular, ×100 objective).

Second Antenna: Protopodite bare (Figure 33h) (without long spines present on S. crux). Endopodite 2-jointed (Figure 33h): 1st joint with 2 small proximal bristles and without medial spines present on S. crux; 2nd joint small with spinous terminal bristle about longer than bristles of 1st joint. Exopodite: joint 1 with small recurved medial terminal bristle; bristles of joints 2–8 with stout proximal ventral spines and distal natatory hairs; 9th joint with 3 bristles (ventral with small proximal ventral spines and distal natatory hairs, middle short with small marginal spines, dorsal short bare and with base medial to middle bristle); joints 2–7 with row of minute spines along distal edges. USNM 193939 with some exopodial bristles broken (may have been broken during dissection).

Mandible (Figure 34a–c): Coxale similar to that of S. crux. Basale: dorsal margin with small unringed spine-like bristle near midlength and 1 longer ringed spinous subterminal bristle; ventral margin with 7 bristles (Figure 34a,b). Exopodite absent. 1st endopodial joint (Figure 34c): dorsal margin with several slender terminal spines; ventral margin with minute spine at midlength, 2 stouter distal spines, and long terminal claw; medial surface with unringed spine-like bristle at base of ventral claw, and slender spines near distal edge. 2nd endopodial joint: dorsal margin with 2 fairly long unringed spine-like subterminal bristles; medial surface with few spines near base of stout ventral claw. 3rd endopodial joint with long terminal claw, 2 short unringed ventral bristles, and 1 minute subterminal unringed dorsal bristle.

Maxilla (Figure 34d,e): Coxale with short dorsal bristle and fringe of long hairs. Endites I and III with 6 bristles; endite II with 4 bristles. Basale with short bristle near exopodite. Exopodite with 2 unequal bristles. Endopodite similar to that of S. crux.

Fifth Limb (Figure 34f): Similar to that of S. crux.

Sixth Limb (Figure 34g): Endite I with 3 short spinous bristles; endite II with 2 long spinous bristles. End joint with 14 or 15 spinous bristles followed by 2 plumose posterior bristles (1 limb of USNM 193939 with only 1 plumose posterior bristle (aberrancy)).

Seventh Limb (Figure 34h): Proximal group with 2 bristles, 1 on each side (1 on segment 9 and 1 on segment 10 counting from segment proximal to terminus), each with 5 bells; terminal group with 6 bristles, 3 on each side, each with 2–6 bells. Terminus with opposing combs, each with 9–12 elongate teeth with recurved bulbous tips; area between opposing combs mound-like.

Furca (Figure 34i): Each lamella with 7 claws; claw 1 nonarticulated; claw 3 about length of claw 4; all claws with teeth along posterior edges.

Bellonci Organ (Figure 33i): Elongate, cylindrical, with 2 weak sutures near midlength, and triangular tip.

Eyes: Medial eye bare, with brown pigment (Figure 33i). Lateral eye unpigmented, smaller than medial eye, with 4 ommatidia.

Genitalia: Oval ring on each side of body anterior to furca.

Upper Lip (Figure 34j,k): Single hirsute lobe without stout anterior spines.

Posterior of Body: Evenly rounded, bare.

Y-Sclerite (Figure 33j): With ventral branch.

Number of Eggs: Holotype with 7 eggs (4 in posterodorsal bulge of right valve, and 3 in left), length of 1 egg 0.31 mm. USNM 193939 with unextruded eggs (this specimen has choniostomatid copepod and copepod egg sacs in marsupium).

Parasites: USNM 193939 with 1 female choniostomatid copepod and 3 copepod egg sacs (1 containing spherical eggs, 2 containing pyriform eggs) in marsupium (location of copepod and egg sac shown in Figure 33c). Both the female copepod and its egg sac mimic the ostracode egg in size (Figure 33k). A similar mimicry has been reported for copepods parasitizing the ostracode Parasterope pollex Kornicker (Bowman and Kornicker, 1967:1).

Ectozoa: USNM 193939 with round Foraminifera attached to outer surface of right valve near posterior end at midheight.

COMPARISONS.—Spinacopia trox is very close to S. crux. It differs in not having spines on either the protopodite or the 1st endopodial joint of the 2nd antenna, in having 9 or 10 rather than 2 or 3 teeth in the terminal combs of the 7th limb as well as a mound between combs, and in the carapace being much larger (length 1.51–1.52 mm compared to 1.10 mm for S. crux). The terminal bristle of the endopodite of the 2nd antenna is shorter on S. trox than on S. crux, but the variability of this character is not known.