Rheina relax Kornicker ex Kornicker & Poore 1996

“Rheina relax Kornicker, new species

Figures 52-54

ETYMOLOGY.—From the Latin relax (loosen, slacken, unbend).

HOLOTYPE.—NMV J40009, undissected ovigerous female in alcohol.

TYPE LOCALITY.—Slope 85, 41°52.87'S, 148°37.93’E to 41°59.56'S, 148°31.13'E, Tasmania, 37 km NE of Cape Tourville, Freycinet Peninsula; collected in 3 m Isaac –Kidd midwater trawl sample that hit bottom; bottom depth 124-478 m. (Because only 1 species was collected (3 adult females plus 3 juveniles), it is likely that specimens came from the water column.)

PARATYPES.—Slope 21:1 partly dissected A-2 juvenile in alcohol (length 1.07 mm, height 0.70 mm); 1 undissected A-2 juvenile in alcohol. Slope 85: USNM 194017, adult female with choniostomatid copepods, on slide and in alcohol; USNM 194018, partly dissected ovigerous female with cryptoniscid isopod in alcohol; NMV J17675, 1 undissected ovigerous female with torn shell in alcohol, lost, and 3 undissected juveniles in alcohol.

DISTRIBUTION.—Slope 21, 220 m. Slope 85, 124-478 m (see "Type Locality" above for comments on depth).

DESCRIPTION OF ADULT FEMALE.— Carapace elongate; anterior edge of rostrum either straight or with slight concavity; posterior end truncate or with very slight concavity at dorsal end of caudal process.

Ornamentation: Carapace smooth but indistinct striations observed on some specimens just posterior to incisur.

Infold: Infold of rostrum with well-defined list with 6 or 7 bristles along anterior half and 1 longer bristle near posterior end; row of 9 bristles dorsal to rostral list and 1 small bristle posterior to row; 2 bristles near inner end of incisur and 1 bristle posterior to them; anteroventral infold and anterior 1/3 of ventral infold with row of about 30 closely spaced bristles; posterior 2/3 of ventral infold with row of about 16 widely spaced bristles; broad list of caudal process with row of 7-9 minute bristles near posterior edge; no bristles posterior to broad list. Right valve with long bar with posterior end just dorsal to broad list of caudal process and anterior end at posterior juncture of hinge.

Selvage: Lamellar prolongation of selvage broad and striate along lower margin of incisur, narrow and without striations elsewhere.

Central Adductor Muscle Attachments: About 18 oval attachments.

Carapace Size (length, height in mm): Slope 85: NMV J40009 (holotype), 1.36, 0.86, height 63% of length; USNM 194017, 1.67, 1.05, height 63% of length; USNM 194018, 1.57, 0.96, height 61% of length; NMV J17675, torn specimen length about 1.6. Length range 1.36-1.67; height range 0.86-1.05; range of height as percent of length 61-63.

First Antenna: 1st joint bare. 2nd joint spinous. 3rd joint short with indistinct medial spines and 2 spinous bristles (1 ventral, 1 dorsal). 4th joint with 2 spinous bristles (1 ventral, 1 dorsal). Sensory bristle of 5th joint with 8 long stout proximal filaments (only proximal part of most filaments shown), 3 shorter slender distal filaments, and bifurcate tip. 6th joint with short spinous medial bristle near dorsal margin. 7th joint: a-bristle longer than bristle of 6th joint, spinous; b-bristle about twice length of a-bristle, with 5 short proximal filaments; c-bristle with tip missing on both limbs of USNM 194017, remaining part longer than bristle of 5th joint, with 7 filaments (some with few spines). 8th joint: d-and e-bristles about twice length of b-bristle, bare with blunt tips; f-bristle long but with tip missing, 8 filaments (some with spines) on remaining part; g-bristle about 1/2 longer than bristle of 5th joint, with 10 filaments (some with spines) and bifurcate tip. (Only a- and b-bristles of 7th joint and no bristles of 8th joint shown.)

Second Antenna: Protopodite with short bare distal medial bristle. Endopodite 3-jointed: 1st joint with 4 proximal bristles (distal of these longer than others) and 1 short distal bristle; 2nd joint very long, bare; 3rd joint short with very long terminal filament. Exopodite: Joint 1 with few distal spines along dorsal margin; bristle of 2nd joint short, reaching 7th joint, ventral margin with 1 slender indistinct proximal spine and 7 stout pointed spines (spine 3rd from last longer than others); bristle of joint 3 long, with about 25 proximal ventral spines (proximal 14 of these fairly transparent), proximal dorsal hairs, and distal hairs on both margins; bristles of joints 4-8 long, with natatory hairs, no spines; 9th joint with 2 long bristles (dorsal of these shorter) with natatory hairs; joints 3-8 with small basal spines increasing in size on distal joints (spine of 8th joint about half length of 9th joint); 9th joint with lateral spine at distal dorsal corner (spine as long as joint); joints 2-8 with minute spines along distal edge; joint 2 also with few indistinct spines along ventral edge.

Mandible: Coxale endite spinous, bifurcate with 2 stout terminal prongs, with unringed bristle near base. Basale: Ventral margin with 2 small a-bristles, 1 small lateral b-bristle, 2 c-bristles, and 2 d-bristles (1 very long); dorsal margin with 3 bristles (1 at distal 2/3, 2 subterminal); medial surface with long spines in proximal ventral corner and short indistinct spines near dorsal edge. Exopodite about same length as dorsal margin of 1st endopodial joint, hirsute distally, with 2 distal ventral bristles (proximal bristle more than twice length of other). 1st endopodial joint with 4 ventral bristles (2 long, 1 short, 1 minute); distal dorsal corner of joint with row of spines. 2nd endopodial joint: Spinous ventral margin with 2 single and 2 paired bristles; medial of paired bristles unringed, stouter than other and with 5 stout dorsal teeth; dorsal margin with about 17 bristles (9 short cleaning bristles with long spines, 1 short bare bristle, and 7 long bristles) (bristles not shown); medial surface with rows of spines. 3rd endopodial joint with 1 slender dorsal claw, 2 stout claws at midwidth, and 3 bristles (longest lateral and with somewhat broader proximal part).

Maxilla: Endite I with 8 spinous bristles (some with spear-like tips and some with triaenid-type tips); endite II with 4 spinous bristles; endite III with 1 proximal bristle (could be interpreted to be on basale) and 5 terminal spinous bristles. Precoxale and coxale with dorsal hairs; coxale with stout hirsute dorsal bristle. Bristles of basale obscured on mounted limbs of USNM 194017, but left limb interpreted to have 2 bristles (1 long, 1 short) and right limb with 1 short bristle. Exopodite well developed, hirsute, with 1 plumose proximal bristle and 2 terminal bristles (middle plumose, other with indistinct short hairs). 1st endopodial joint; cutting tooth with 3 cusps; dorsal margin spinous, with 2 spinous alpha-bristles; ventral margin with 2 beta-bristles (medial bristle stout pectinate, lateral bristle shorter slender bare). 2nd endopodial joint with 3 a-bristles (inner 2 pectinate, outer bare), 2 spinous b-bristles (1 more than twice length of other), 2 pectinate c-bristles, and 3 pectinate d-bristles (posterior ringed, 2 others unringed, claw-like). (Right limb twisted.)

Fifth Limb: 3 endites with spinous and pectinate bristles. Protopodite with short lobate sclerotized anterior tooth. 1st exopodial joint: anterior side with row of 3 bristles (with long proximal hairs) plus 1 bristle with long proximal hairs closer to protopodial tooth; main tooth with smooth triangular proximal tooth and 6 pectinate teeth; bristle with long proximal hairs proximal to smooth tooth. 2nd exopodial joint: with 3 pectinate a-bristles (smallest bristle weakly ringed, others unringed), 6 ringed pectinate b-bristles (only 2 b-bristles shown), 1 stout c-bristle with long proximal and short distal spines, and 1 stout d-bristle with long proximal hairs. 3rd exopodial joint: Inner lobe with short proximal bristle with long proximal hairs, and 2 terminal bristles with short hairs; outer lobe hirsute, with 2 terminal bristles (outer with long proximal and short distal spines, inner with few indistinct short hairs). 4th and 5th exopodial joints fused, hirsute, each estimated joint with 2 bristles; short slender process with terminal spines present between estimated joints.

Sixth Limb: With 4 bare epipodial bristles. Endite I with 2 short medial and 1 long terminal bristle; endite II with either 1 short medial and 3 terminal bristles (middle bristle short, with base on medial side of edge), or 2 short medial and 2 long terminal bristles; endite III with 1 medial and 3 terminal bristles; endite IV with 1 medial and 2 terminal bristles; all endite bristles spinous. End joint with 7 anterior bristles (with 1 wreath of long proximal spines and short distal spines) followed by 1 bristle (with many long proximal and short distal spines) and 2 plumose bristles. Medial side of limb hirsute (not all hairs shown); lateral side of end joint with long stiff spines. Limb with brown pigment indicated by stippling in illustration.

Seventh Limb: Limb with 15-17 bristles: 2-4 proximal and 6 terminal on comb side; 4 proximal and 3 terminal on jaw side; bristles with 1-5 bells. Comb with 11 teeth (3 long teeth in middle, 2 shorter narrow teeth (with indistinct marginal spines) and 2 short broad flat-tipped teeth on each side); a short sclerotized prong with 3 minute teeth located along inner side of comb (detail in illustration). A sclerotized jaw with about 14 teeth (2 large and about 5 small along each edge) just proximal to inner bristles at base of comb.

Furca: Right lamella anterior to left by width of base of claw 1; each lamella with 9 claws; claw 3 slenderer than claw 4 but about same length; claws 2 and 4 nonarticulated; all claws with teeth along posterior margins. (Illustrated furca with most claws broken.)

Bellonci Organ: Short, cylindrical, with triangular tip with small terminal process.

Eyes: Medial eye small, bare, with brown pigment (stippled). Lateral eye large, about 3 times size of medial eye, with about 24 ommatidia and brown pigment (stippled) between ommatidia.

Upper Lip: Anteroventral unpaired part with fairly large glandular processes; paired tusks well developed, each with proximal pedestal, 3 or 4 glandular openings near tip, and with long hairs along anterior and posterior edges; posterior lobes of lip evenly rounded, hirsute.

Genitalia: Unusually large lobe with attached spermatophore on each side of body just anterior to furca.

Anterior of Body: With rounded anterior process between medial eye and upper lip.

Posterior of Body: Evenly rounded, bare.

Y-Sclerite: Typical for subfamily.

Eggs: Holotype with 8 eggs in marsupium, length of typical egg 0.29 mm; USNM 194018 with 8 eggs (length of typical egg including transparent vellum 0.31 mm; length without vellum 0.28 mm); NMV J17675, torn specimen with 1 egg in marsupium (some may have been lost), length with vellum 0.33 mm, length without vellum, 0.27 mm.

Parasites: USNM 194017 with choniostomatid copepods in marsupium: 1 female, 1 copepodite, and 14 egg sacs (some egg sacs with fairly well-developed copepodites, others with round eggs); USNM 194018 with 1 male or juvenile cryptoniscid isopod within ostracode carapace (ventral side of isopod adjacent to ventral part of body of ostracode; anterior end of isopod pointing anteriorly).

COMPARISONS.—Rheina relax differs from R. prex in having a lateral eye, in having both claws 2 and 4 of furca unarticulated, in having a jaw on the 7th limb, and in having only 2 bristles on the 9th exopodial joint of the 2nd antenna.”

(Kornicker & Poore, 1996, p.95-100)

Rheina relax Kornicker

ETYMOLOGY.—From the Latin relax (loosen, slacken, unbend).

HOLOTYPE.—NMV J40009, undissected ovigerous female in alcohol.

TYPE LOCALITY.—Slope 85, 41°52.87′S, 148°37.93′E to 41°59.56′S, 148°31.13′E, Tasmania, 37 km NE of Cape Tourville, Freycinet Peninsula; collected in 3 m Isaac-Kidd midwater trawl sample that hit bottom; bottom depth 124–478 m. (Because only 1 species was collected (3 adult females plus 3 juveniles), it is likely that specimens came from the water column.)

PARATYPES.—Slope 21: 1 partly dissected A–2 juvenile in alcohol (length 1.07 mm, height 0.70 mm); 1 undissected A–2 juvenile in alcohol. Slope 85: USNM 194017, adult female with choniostomatid copepods, on slide and in alcohol; USNM 194018, partly dissected ovigerous female with cryptoniscid isopod in alcohol; NMV J17675, 1 undissected ovigerous female with torn shell in alcohol, lost, and 3 undissected juveniles in alcohol.

DISTRIBUTION.—Slope 21, 220 m. Slope 85, 124–478 m (see “Type Locality” above for comments on depth).

DESCRIPTION OF ADULT FEMALE (Figures 52–54).—Carapace elongate (Figure 52a,d); anterior edge of rostrum either straight (Figure 52e) or with slight concavity (Figure 52a); posterior end truncate (Figure 52a,c) or with very slight concavity at dorsal end of caudal process (Figure 52h,i).

Ornamentation: Carapace smooth but indistinct striations observed on some specimens just posterior to incisur (Figure 52b).

Infold: Infold of rostrum with well-defined list with 6 or 7 bristles along anterior half and 1 longer bristle near posterior end (Figure 52f,g); row of 9 bristles dorsal to rostral list and 1 small bristle posterior to row; 2 bristles near inner end of incisur and 1 bristle posterior to them; anteroventral infold and anterior of ventral infold with row of about 30 closely spaced bristles; posterior of ventral infold with row of about 16 widely spaced bristles; broad list of caudal process with row of 7–9 minute bristles near posterior edge (Figure 52h,i); no bristles posterior to broad list. Right valve with long bar with posterior end just dorsal to broad list of caudal process and anterior end at posterior juncture of hinge (Figure 52g,i).

Selvage: Lamellar prolongation of selvage broad and striate along lower margin of incisur, narrow and without striations elsewhere.

Central Adductor Muscle Attachments (Figure 52j): About 18 oval attachments.

Carapace Size (length, height in mm): Slope 85: NMV J40009 (holotype), 1.36, 0.86, height 63% of length; USNM 194017, 1.67, 1.05, height 63% of length; USNM 194018, 1.57, 0.96, height 61% of length; NMV J17675, torn specimen length about 1.6. Length range 1.36–1.67; height range 0.86–1.05; range of height as percent of length 61–63.

First Antenna (Figure 53a): 1st joint bare. 2nd joint spinous. 3rd joint short with indistinct medial spines and 2 spinous bristles (1 ventral, 1 dorsal). 4th joint with 2 spinous bristles (1 ventral, 1 dorsal). Sensory bristle of 5th joint with 8 long stout proximal filaments (only proximal part of most filaments shown), 3 shorter slender distal filaments, and bifurcate tip. 6th joint with short spinous medial bristle near dorsal margin. 7th joint: a-bristle longer than bristle of 6th joint, spinous; b-bristle about twice length of a-bristle, with 5 short proximal filaments; c-bristle with tip missing on both limbs of USNM 194017, remaining part longer than bristle of 5th joint, with 7 filaments (some with few spines). 8th joint: d-and e-bristles about twice length of b-bristle, bare with blunt tips; f-bristle long but with tip missing, 8 filaments (some with spines) on remaining part; g-bristle about longer than bristle of 5th joint, with 10 filaments (some with spines) and bifurcate tip. (Only a- and b-bristles of 7th joint and no bristles of 8th joint shown.)

Second Antenna: Protopodite with short bare distal medial bristle (Figure 53b). Endopodite 3-jointed (Figure 53b): 1st joint with 4 proximal bristles (distal of these longer than others) and 1 short distal bristle; 2nd joint very long, bare; 3rd joint short with very long terminal filament. Exopodite: Joint 1 with few distal spines along dorsal margin; bristle of 2nd joint short, reaching 7th joint, ventral margin with 1 slender indistinct proximal spine and 7 stout pointed spines (spine 3rd from last longer than others); bristle of joint 3 long, with about 25 proximal ventral spines (proximal 14 of these fairly transparent), proximal dorsal hairs, and distal hairs on both margins; bristles of joints 4–8 long, with natatory hairs, no spines; 9th joint with 2 long bristles (dorsal of these shorter) with natatory hairs; joints 3–8 with small basal spines increasing in size on distal joints (spine of 8th joint about half length of 9th joint); 9th joint with lateral spine at distal dorsal comer (spine as long as joint); joints 2–8 with minute spines along distal edge; joint 2 also with few indistinct spines along ventral edge.

Mandible: Coxale endite spinous, bifurcate with 2 stout terminal prongs, with unringed bristle near base. Basale (Figure 53c): Ventral margin with 2 small a-bristles, 1 small lateral b-bristle, 2 c-bristles, and 2 d-bristles (1 very long); dorsal margin with 3 bristles (1 at distal , 2 subterminal); medial surface with long spines in proximal ventral comer and short indistinct spines near dorsal edge. Exopodite about same length as dorsal margin of 1st endopodial joint, hirsute distally, with 2 distal ventral bristles (proximal bristle more than twice length of other). 1st endopodial joint with 4 ventral bristles (2 long, 1 short, 1 minute); distal dorsal comer of joint with row of spines (Figure 53c). 2nd endopodial joint (Figure 53d): Spinous ventral margin with 2 single and 2 paired bristles; medial of paired bristles unringed, stouter than other and with 5 stout dorsal teeth; dorsal margin with about 17 bristles (9 short cleaning bristles with long spines, 1 short bare bristle, and 7 long bristles) (bristles not shown); medial surface with rows of spines. 3rd endopodial joint with 1 slender dorsal claw, 2 stout claws at midwidth, and 3 bristles (longest lateral and with somewhat broader proximal part (2 long bristles not shown in Figure 53d, but detail shows proximal part of longest bristle)).

Maxilla: Endite I with 8 spinous bristles (some with spear-like tips and some with triaenid-type tips); endite II with 4 spinous bristles; endite III with 1 proximal bristle (could be interpreted to be on basale) and 5 terminal spinous bristles. Precoxale and coxale with dorsal hairs (Figure 53e); coxale with stout hirsute dorsal bristle (Figure 53e). Bristles of basale obscured on mounted limbs of USNM 194017, but left limb interpreted to have 2 bristles (1 long, 1 short) (Figure 53g) and right limb with 1 short bristle (Figure 53e). Exopodite well developed, hirsute, with 1 plumose proximal bristle and 2 terminal bristles (middle plumose, other with indistinct short hairs) (Figure 53e). 1st endopodial joint; cutting tooth with 3 cusps (Figure 53e) (cusps not shown in Figure 53g); dorsal margin spinous, with 2 spinous alpha-bristles; ventral margin with 2 beta-bristles (medial bristle stout pectinate, lateral bristle shorter slender bare) (Figure 53e). 2nd endopodial joint with 3 a-bristles (inner 2 pectinate, outer bare) (Figure 53e), 2 spinous b-bristles (1 more than twice length of other), 2 pectinate c-bristles, and 3 pectinate d-bristles (posterior ringed, 2 others unringed, claw-like) (Figure 53f,h). (Right limb twisted (Figure 53e).)

Fifth Limb: 3 endites with spinous and pectinate bristles (not all shown in Figures 54b). Protopodite with short lobate sclerotized anterior tooth (Figure 54a). 1st exopodial joint: anterior side with row of 3 bristles (with long proximal hairs) plus 1 bristle with long proximal hairs closer to protopodial tooth (Figure 54a); main tooth with smooth triangular proximal tooth and 6 pectinate teeth (Figure 54b); bristle with long proximal hairs proximal to smooth tooth. 2nd exopodial joint: with 3 pectinate a-bristles (smallest bristle weakly ringed, others unringed), 6 ringed pectinate b-bristles (only 2 b-bristles shown), 1 stout c-bristle with long proximal and short distal spines (Figure 54b), and 1 stout d-bristle with long proximal hairs (Figure 54a). 3rd exopodial joint (Figure 54a): Inner lobe with short proximal bristle with long proximal hairs, and 2 terminal bristles with short hairs; outer lobe hirsute, with 2 terminal bristles (outer with long proximal and short distal spines, inner with few indistinct short hairs). 4th and 5th exopodial joints fused, hirsute, each estimated joint with 2 bristles; short slender process with terminal spines present between estimated joints (Figure 54a).

Sixth Limb (Figure 54c): With 4 bare epipodial bristles. Endite I with 2 short medial and 1 long terminal bristle; endite II with either 1 short medial and 3 terminal bristles (middle bristle short, with base on medial side of edge) (Figure 54c), or 2 short medial and 2 long terminal bristles; endite III with 1 medial and 3 terminal bristles; endite IV with 1 medial and 2 terminal bristles; all endite bristles spinous. End joint with 7 anterior bristles (with 1 wreath of long proximal spines and short distal spines) followed by 1 bristle (with many long proximal and short distal spines) and 2 plumose bristles. Medial side of limb hirsute (not all hairs shown); lateral side of end joint with long stiff spines. Limb with brown pigment indicated by stippling in illustration.

Seventh Limb (Figure 54d): Limb with 15–17 bristles: 2–4 proximal and 6 terminal on comb side; 4 proximal and 3 terminal on jaw side; bristles with 1–5 bells. Comb with 11 teeth (3 long teeth in middle, 2 shorter narrow teeth (with indistinct marginal spines) and 2 short broad flat-tipped teeth on each side); a short sclerotized prong with 3 minute teeth located along inner side of comb (detail in illustration). A sclerotized jaw with about 14 teeth (2 large and about 5 small along each edge) just proximal to inner bristles at base of comb.

Furca (Figure 53i): Right lamella anterior to left by width of base of claw 1; each lamella with 9 claws; claw 3 slenderer than claw 4 but about same length; claws 2 and 4 nonarticulated; all claws with teeth along posterior margins (not shown). (Illustrated furca with most claws broken.)

Bellonci Organ (Figure 54e,f): Short, cylindrical, with triangular tip with small terminal process.

Eyes: Medial eye small, bare, with brown pigment (stippled) (Figure 54e,f). Lateral eye large, about 3 times size of medial eye, with about 24 ommatidia and brown pigment (stippled) between ommatidia (Figure 54g).

Upper Lip (Figure 53j): Anteroventral unpaired part with fairly large glandular processes; paired tusks well developed, each with proximal pedestal, 3 or 4 glandular openings near tip, and with long hairs along anterior and posterior edges; posterior lobes of lip evenly rounded, hirsute.

Genitalia (Figure 54h): Unusually large lobe with attached spermatophore on each side of body just anterior to furca.

Anterior of Body (Figure 54e): With rounded anterior process between medial eye and upper lip.

Posterior of Body (Figure 54h): Evenly rounded, bare.

Y-Sclerite: Typical for subfamily (only posterior end shown in Figure 54h).

Eggs: Holotype with 8 eggs in marsupium, length of typical egg 0.29 mm; USNM 194018 with 8 eggs (length of typical egg including transparent vellum 0.31 mm; length without vellum 0.28 mm) (1 egg shown in Figure 52a); NMV J17675, torn specimen with 1 egg in marsupium (some may have been lost), length with vellum 0.33 mm, length without vellum, 0.27 mm.

Parasites: USNM 194017 with choniostomatid copepods in marsupium: 1 female, 1 copepodite, and 14 egg sacs (some egg sacs with fairly well-developed copepodites, others with round eggs (Figure 52d)); USNM 194018 with 1 male or juvenile cryptoniscid isopod within ostracode carapace (ventral side of isopod adjacent to ventral part of body of ostracode; anterior end of isopod pointing anteriorly (Figure 52a)).

COMPARISONS.—Rheina relax differs from R. prex in having a lateral eye, in having both claws 2 and 4 of furca unarticulated, in having a jaw on the 7th limb, and in having only 2 bristles on the 9th exopodial joint of the 2nd antenna.

AZYGOCYPRIDININAE Kornicker, 1970

This subfamily includes two genera, Azygocypridina Sylvester-Bradley, 1950, and Isocypridina Kornicker, 1975; both genera are in the collection.

Azygocypridina Sylvester-Bradley, 1950

TYPE SPECIES.—Crossophorus imperator Brady, 1880:158, by monotypy.

COMPOSITION.—Only 1 species is known from Australia, A. lowryi Kornicker, 1985:698.

DISTRIBUTION.—Genus cosmopolitan, but not known from Arctic waters, reported between depths of 139 m (Kornicker, 1985:698) and 2930 m (Athersuch, 1980:139).