Neomuelleriella nex Kornicker 1995

“Neomuelleriella nex, new species

Figures 47, 48

ETYMOLOGY.—From the Latin nex (violent death).

HOLOTYPE.—Undissected ovigerous female in alcohol in collection of the Museum of Victoria.

TYPE LOCALITY.—Slope 22, 37°0.60’S, 150°20.70’E, New South Wales, off Eden, depth 363 m.

PARATYPES.—Slope 22: 8 specimens (1 ovigerous female in alcohol + 1 adult female with choniostomatid copepods (female, male, and egg sac) + 3 adult females without eggs + 1 juvenile male + 2 specimens) in alcohol. Slope 40: USNM 193992, adult female on slide and in alcohol.

DISTRIBUTION.—Slope 22, 363 m. Slope 40,400 m.

DESCRIPTION OF ADULT FEMALE.— Subround in lateral view, without projecting caudal process; posterodorsal margin less convex than anterior and ventral margins. Surface without gel-like coating.

Ornamentation: Surface with numerous long stout bristles with sides parallel almost to tip (bristles shorter (many bent) on anterior half of valve), and fewer long and short bristles with or without proximal swelling (these more abundant on or near valve margins; valve surface with abundant minute spines (more easily visible along valve edges) (not shown). Surface bristles only slightly denser in caudal area.

Infold: Anterior infold with 1 small bristle near inner margin. Infold of caudal region with row of 11 or 12 short bristles near midwidth and several minute bristles along inner margin; 2 setal bristles dorsal to caudal area.

Central Adductor Muscle Attachments: Comprising about 20 individual ovoid scars.

Carapace Size (length, height in mm): Slope 22: holotype, 0.91,0.83. 2 specimens with choniostomatids: 0.83,0.73; 0.88, 0.73. 2 specimens without eggs: 0.85, 0.78; 0.81, 0.75. 1 specimen with 3 eggs, 0.82, 0.76. Slope 40: USNM 193992, 0.90, 0.76.

First Antenna: 1st joint bare. 2nd joint with proximal dorsal spines, row of lateral spines along distal edge, and 1 dorsal bristle with long proximal and short distal spines. 3rd joint fused to 4th, with 2 spinous bristles (1 dorsal, 1 ventral). 4th joint with 2 bristles (1 ventral long, 1 dorsal short) with indistinct short spines. Sensory bristle of 5th joint with 2 proximal filaments and 1 minute subterminal spine. 6th joint with small medial bristle with short spines (spines not shown). 7th joint: a-bristle with short marginal spines; b-bristle slightly longer than a-bristle, bare; c-bristle slightly longer than bristle of 5th joint, with 3 minute filaments along middle part and 2 minute spines near tip. 8th joint: d- and e-bristles about same length as c-bristle, bare with blunt tips; f-bristle with 1 minute proximal filament and 1 minute spine at midlength (tip of bristle missing); g-bristle with minute proximal filament and 1 minute spine near tip.

Second Antenna: Protopodite with long medial hairs near endopodite. Endopodite either 2-jointed (1st joint with small proximal bristle; 2nd joint short bare), or 3-jointed (1st joint with small proximal bristle; 2nd joint elongate bare; 3rd joint short with small terminal ringed bristle). Exopodite: 1st joint with small curved tubular medial bristle on distal edge; bristles of joints 2-8 with slender ventral spines followed by natatory hairs; 9th joint with 2 bristles (1 long ventral with slender ventral spines followed by natatory hairs, 1 short dorsal, either bare or with few indistinct hair-like spines); joints 3-8 with row of minute spines along distal edges.

Mandible: Coxale endite stout spine-like; coxale with rows of ventral hairs. Basale: dorsal margin with 1 minute spine distal to midlength and 1 short subterminal spine-like bristle; ventral margin with 3 small medial bristles and 1 small lateral bristle. Exopodite represented by small process with terminal spine. 1st endopodial joint with few medial spines along distal edge, few terminal dorsal spines, and 1 medial spine-like bristle near base of stout ventral claw. 2nd endopodial joint with 2 small, spine-like, subterminal, dorsal bristles and stout terminal ventral claw. 3rd endopodial joint with stout terminal claw with 2 small indistinct bristles near base (1 ventral, 1 dorsal).

Maxilla: Endites I—III each with 5 or 6 bristles. Coxale with short dorsal bristle. Basale with ventral bristle near exopodite. Exopodite small with 2 bristles. 1st endopodial joint with few anterior spines and spinous alpha- and beta-bristles. 2nd endopodial joint with 2 a-bristles, 1 c-bristle (shorter than a-bristles), and 5 pectinate end bristles.

Fifth Limb: Epipodite with 31 bristles. Single endite with small bare bristle. Exopodite: 1st joint with 2 spinous bristles; 2nd joint with 3 spinous bristles; 3rd joint with 1 spinous bristle on outer lobe and 3 on inner lobe; fused 4th and 5th joints close to inner lobe of 3rd joint, with total of 2 spinous bristles (limb could be interpreted as having inner lobe of 3rd joint fused to 4th and 5th joints). Limb hirsute.

Sixth Limb: Endite I with 3 short bristles; endite II with 5 long spinous bristles. End joint with 9 bristles with short spines followed by 2 posterior plumose bristles (plumose bristles broken on illustrated limb; 1 bristle near anterior of end joint of illustrated limb only partly extruded (dashed) [in cited text]).

Seventh Limb: Proximal group with 4 bristles (2 on each side with 3 (rarely 4) bells; terminal group with 6 bristles (3 on each side with 2-6 bells). Terminus with comb of about 9 teeth opposite 2 small pegs.

Furca: Each lamella with 6 claws; only claw 1 nonarticulated; claw 3 shorter and slenderer than claw 4; all claws with teeth along posterior edge (not all shown); edge of lamellae following claws with spines (more spines on left lamella); right lamella with spines along anterior edge, and rows of long medial hairs near anterior edge and at base of claw 1.

Bellonci Organ: Elongate with 2 weakly developed sutures near midlength and minute process at tip.

Eyes: Lateral eye minute, with brown pigment and about 5 amber-colored cells (ommatidia ?). Medial eye with brown pigment, bare, much larger than lateral eye.

Upper Lip: Evenly rounded.

Genitalia: Oval genitalia with attached spermatophore.

Anterior of Body: With small triangular process on each side dorsal to upper lip.

Posterior of Body: Evenly rounded, bare.

Y-Sclerite: With ventral branch.

Number of Eggs: Slope 22: holotype with 3 eggs in marsupium, length of 1 egg 0.25 mm; unnumbered specimen with 3 eggs, length of 1 egg 0.25 mm.

Parasites: Adult female from Slope 22 with choniostomatids (female, male, egg sac) within marsupium.

DESCRIPTION OF A-l MALE.—Shape of carapace similar to that of adult female.

Ornamentation: Without parallel-sided bristles present on adult female; most bristles taper to slender tip; some bristles with swelling at proximal 2/3.

Infold: Not examined.

Central Adductor Muscle Attachments: Comprising at least 16 ovoid scars.

Carapace Size (length, height in mm): Specimen from Slope 22: 0.73, 0.64.

First Antenna: Distribution of bristles similar to that of adult female.

Second Antenna: Protopodite with long medial hairs and skeletal structure similar to those of adult female. Endopodite 3-jointed: 1st joint short with short proximal ventral bristle; 2nd joint elongate with 2 short proximal ventral bristles; 3rd joint elongate with 2 small terminal bristles. Exopodite: bristles of similar length to those of adult female and with similar spines and natatory hairs; joints with spines similar to those of adult female.

Maxilla: Exopodite and endopodite similar to those of adult female; remaining part of limb not examined.

Seventh Limb: Well developed; proximal group with 2 tapered bristles (1 on each side, each with 2 bells); terminal group with 4 tapered bristles (2 on each side, each with 3 or 4 bells); "clapper" of each terminal bell relatively longer than those of adult female. Terminus without comb or pegs.

Furca and Eyes: Similar to those of adult female.

Bellonci Organ: Similar to that of adult female except for having rounded tip.

COMPARISONS.—The carapace of N. nex differs from those of N. zealandica and N. hispida in not having a projecting caudal process. Except for being smaller the carapace of N. nex resembles Chelicopia pertinax Kornicker, 1994, but the furca of that species has claws 2 and 4 on each lamella of the furca nonarticulated.”

(Kornicker, 1995, p.77-81)

Neomuelleriella nex

ETYMOLOGY.—From the Latin nex (violent death).

HOLOTYPE.—Undissected ovigerous female in alcohol in collection of the Museum of Victoria.

TYPE LOCALITY.—Slope 22, 37°0.60′S, 150°20.70′E, New South Wales, off Eden, depth 363 m.

PARATYPES.—Slope 22: 8 specimens (1 ovigerous female in alcohol + 1 adult female with choniostomatid copepods (female, male, and egg sac) + 3 adult females without eggs + 1 juvenile male + 2 specimens) in alcohol. Slope 40: USNM 193992, adult female on slide and in alcohol.

DISTRIBUTION.—Slope 22, 363 m. Slope 40, 400 m.

DESCRIPTION OF ADULT FEMALE (Figures 47, 48a–j).—Subround in lateral view, without projecting caudal process; posterodorsal margin less convex than anterior and ventral margins. Surface without gel-like coating.

Ornamentation (Figure 47a,b): Surface with numerous long stout bristles with sides parallel almost to tip (bristles shorter (many bent) on anterior half of valve), and fewer long and short bristles with or without proximal swelling (these more abundant on or near valve margins (Figure 47b); valve surface with abundant minute spines (more easily visible along valve edges) (not shown). Surface bristles only slightly denser in caudal area (Figure 47a).

Infold: Anterior infold with 1 small bristle near inner margin (Figure 47b). Infold of caudal region with row of 11 or 12 short bristles near midwidth and several minute bristles along inner margin; 2 setal bristles dorsal to caudal area (Figure 47c).

Central Adductor Muscle Attachments (Figure 47d): Comprising about 20 individual ovoid scars.

Carapace Size (length, height in mm): Slope 22: holotype, 0.91, 0.83. 2 specimens with choniostomatids: 0.83, 0.73; 0.88, 0.73. 2 specimens without eggs: 0.85, 0.78; 0.81, 0.75. 1 specimen with 3 eggs, 0.82, 0.76. Slope 40: USNM 193992, 0.90, 0.76.

First Antenna (Figure 47e): 1st joint bare. 2nd joint with proximal dorsal spines, row of lateral spines along distal edge, and 1 dorsal bristle with long proximal and short distal spines. 3rd joint fused to 4th, with 2 spinous bristles (1 dorsal, 1 ventral). 4th joint with 2 bristles (1 ventral long, 1 dorsal short) with indistinct short spines. Sensory bristle of 5th joint with 2 proximal filaments and 1 minute subterminal spine. 6th joint with small medial bristle with short spines (spines not shown). 7th joint: a-bristle with short marginal spines; b-bristle slightly longer than a-bristle, bare; c-bristle slightly longer than bristle of 5th joint, with 3 minute filaments along middle part and 2 minute spines near tip. 8th joint: d- and e-bristles about same length as c-bristle, bare with blunt tips; f-bristle with 1 minute proximal filament and 1 minute spine at midlength (tip of bristle missing); g-bristle with minute proximal filament and 1 minute spine near tip.

Second Antenna: Protopodite with long medial hairs near endopodite (Figure 47f,g). Endopodite either 2-jointed (1st joint with small proximal bristle; 2nd joint short bare) (Figure 47g), or 3-jointed (1st joint with small proximal bristle; 2nd joint elongate bare; 3rd joint short with small terminal ringed bristle) (Figure 47f). Exopodite: 1st joint with small curved tubular medial bristle on distal edge; bristles of joints 2–8 with slender ventral spines followed by natatory hairs; 9th joint with 2 bristles (1 long ventral with slender ventral spines followed by natatory hairs, 1 short dorsal, either bare or with few indistinct hair-like spines); joints 3–8 with row of minute spines along distal edges.

Mandible (Figure 48a,b): Coxale endite stout spine-like; coxale with rows of ventral hairs. Basale: dorsal margin with 1 minute spine distal to midlength and 1 short subterminal spine-like bristle; ventral margin with 3 small medial bristles and 1 small lateral bristle. Exopodite represented by small process with terminal spine (Figure 48b). 1st endopodial joint with few medial spines along distal edge, few terminal dorsal spines, and 1 medial spine-like bristle near base of stout ventral claw. 2nd endopodial joint with 2 small, spine-like, subterminal, dorsal bristles and stout terminal ventral claw. 3rd endopodial joint with stout terminal claw with 2 small indistinct bristles near base (1 ventral, 1 dorsal).

Maxilla: Endites I–III each with 5 or 6 bristles. Coxale with short dorsal bristle (Figure 48c). Basale with ventral bristle near exopodite. Exopodite small with 2 bristles (Figure 48c,d). 1st endopodial joint with few anterior spines and spinous alpha- and beta-bristles. 2nd endopodial joint with 2 a-bristles (not shown), 1 c-bristle (shorter than a-bristles), and 5 pectinate end bristles.

Fifth Limb (Figure 48e): Epipodite with 31 bristles. Single endite with small bare bristle. Exopodite: 1st joint with 2 spinous bristles; 2nd joint with 3 spinous bristles; 3rd joint with 1 spinous bristle on outer lobe and 3 on inner lobe; fused 4th and 5th joints close to inner lobe of 3rd joint, with total of 2 spinous bristles (limb could be interpreted as having inner lobe of 3rd joint fused to 4th and 5th joints). Limb hirsute.

Sixth Limb (Figure 48f): Endite I with 3 short bristles; endite II with 5 long spinous bristles. End joint with 9 bristles with short spines followed by 2 posterior plumose bristles (plumose bristles broken on illustrated limb; 1 bristle near anterior of end joint of illustrated limb only partly extruded (dashed)).

Seventh Limb (Figure 48g): Proximal group with 4 bristles (2 on each side with 3 (rarely 4) bells; terminal group with 6 bristles (3 on each side with 2–6 bells). Terminus with comb of about 9 teeth opposite 2 small pegs.

Furca (Figure 48h,i): Each lamella with 6 claws; only claw 1 nonarticulated; claw 3 shorter and slenderer than claw 4; all claws with teeth along posterior edge (not all shown); edge of lamellae following claws with spines (more spines on left lamella); right lamella with spines along anterior edge, and rows of long medial hairs near anterior edge and at base of claw 1.

Bellonci Organ (Figure 47h,i): Elongate with 2 weakly developed sutures near midlength and minute process at tip.

Eyes: Lateral eye minute, with brown pigment and about 5 amber-colored cells (ommatidia ?) (Figure 47h). Medial eye with brown pigment, bare, much larger than lateral eye (Figure 47h,i).

Upper Lip (Figure 47h): Evenly rounded.

Genitalia (Figure 48j): Oval genitalia with attached spermatophore.

Anterior of Body (Figure 47h): With small triangular process on each side dorsal to upper lip.

Posterior of Body: Evenly rounded, bare.

Y-Sclerite (Figure 48j): With ventral branch.

Number of Eggs: Slope 22: holotype with 3 eggs in marsupium, length of 1 egg 0.25 mm; unnumbered specimen with 3 eggs, length of 1 egg 0.25 mm.

Parasites: Adult female from Slope 22 with choniostomatids (female, male, egg sac) within marsupium.

DESCRIPTION OF A–1 MALE (Figure 48k–n).—Shape of carapace similar to that of adult female (Figure 48k).

Ornamentation (Figure 48k): Without parallel-sided bristles present on adult female; most bristles taper to slender tip; some bristles with swelling at proximal .

Infold: Not examined.

Central Adductor Muscle Attachments (Figure 48k): Comprising at least 16 ovoid scars.

Carapace Size (length, height in mm): Specimen from Slope 22: 0.73, 0.64.

First Antenna: Distribution of bristles similar to that of adult female.

Second Antenna: Protopodite with long medial hairs and skeletal structure similar to those of adult female. Endopodite 3-jointed (Figure 48l): 1st joint short with short proximal ventral bristle; 2nd joint elongate with 2 short proximal ventral bristles; 3rd joint elongate with 2 small terminal bristles. Exopodite: bristles of similar length to those of adult female and with similar spines and natatory hairs; joints with spines similar to those of adult female.

Maxilla: Exopodite and endopodite similar to those of adult female; remaining part of limb not examined.

Seventh Limb (Figure 48m): Well developed; proximal group with 2 tapered bristles (1 on each side, each with 2 bells); terminal group with 4 tapered bristles (2 on each side, each with 3 or 4 bells); “clapper” of each terminal bell relatively longer than those of adult female. Terminus without comb or pegs.

Furca and Eyes (Figure 48n): Similar to those of adult female.

Bellonci Organ (Figure 48n): Similar to that of adult female except for having rounded tip.

COMPARISONS.—The carapace of N. nex differs from those of N. zealandica and N. hispida in not having a projecting caudal process. Except for being smaller the carapace of N. nex resembles Chelicopia pertinax Kornicker, 1994, but the furca of that species has claws 2 and 4 on each lamella of the furca nonarticulated.