Skogsbergia vivax Kornicker ex Kornicker & Poore 1996

Skogsbergia vivax Kornicker

ETYMOLOGY.—From the Latin vivax (lively).

HOLOTYPE.—NMV J40012, ovigerous female on slide and in alcohol.

TYPE LOCALITY.—Slope 40, 38°17.70′S, 149°11.30′E, Victoria, S of Point Hicks; depth 400 m.

PARATYPES.—Slope 40: NMV J40013, 1 ovigerous female; NMV J40014, 5 adult females; and NMV J40015, 9 specimens, all in alcohol.

DISTRIBUTION.—Slope 40, 400 m.

DESCRIPTION OF ADULT FEMALE (Figures 44–47).—Carapace elongate with convex dorsal and ventral margins and elongate caudal process with narrowly rounded tip (Figure 44e). Dorsal margin of caudal process forming obtuse angle with posterior margin of valve dorsal to caudal process (Figure 44a,e,f) (without notch that is present on S. hesperidea (Müller, 1906, fig. XXX: 21, 25). Anterior corner of rostrum narrowly rounded but proximal posterior corner with medial flap-like extension (Figure 44a,c,d); inside edge of right valve dorsal to rostrum with sclerotized bar with knob-like anterior end (Figure 44d); outer surface with 2 narrow curved ridges extending from vicinity of inner end of incisur to anterior edge of valve ventral to incisur (posterior ridge scalloped) (Figure 44a,b).

Infold: Rostral infold with 26–28 bristles (2 bristles missing on illustrated right valve of holotype, but their past presence indicated by empty sockets) (Figure 44c,d); 2 divided bristles (anterior longer) at inner end of incisur and 1 small bristle just inward from them; 2 small bristles near ventral inner end of incisur (Figure 44c,d). Narrow list extends from anteroventral infold (anterior end shown in Figure 44c,d), continues along ventral margin close to valve edge, and then broadens to form wide shelf close to inner margin of infold at anterior end of caudal process (Figure 44e,f). Anteroventral list scalloped and with about 25 divided bristles (3 additional divided bristles in row anterior to anterior end of list (Figure 44c,d) (2 or 3 list bristles shown in Figure 44c,d); anterior end of unscalloped ventral list with about 15 closely spaced divided bristles forming row continuing from anteroventral row; middle part of ventral infold with few widely spaced long bristles; posterior part of ventral infold with few minute widely spaced spine-like bristles along list. Posterior edge of broad list at anterior end of caudal process with small processes, some with minute papilla (Figure 44e,f); flat surface of broad list with row of minute spines inward from posterior edge; sclerotized bar (dashed in Figure 44e,f) beneath broad list of both valves, but better developed in left valve where outer edge forms right angle at dorsal end (Figure 44e).

Selvage: Lamellar prolongation of selvage narrow and nonstriate along dorsal and anterior margins of rostrum but broad and narrowly striate along dorsal margin of incisur; prolongation divided at inner end of incisur, broad and narrowly striate along ventral margin of incisur, and narrow and nonstriate along anteroventral and ventral margins of valve; prolongation absent at both tip and dorsal margin of caudal process and posterior and dorsal margins of valve.

Central Adductor Muscle Attachments: Obscured on undissected specimen, but comprising at least 13 elongate and oval attachments on valve with body removed, which may not show all muscle attachments (Figure 44g).

Carapace Size (length, height in mm): Slope 40: NMV J40012 (holotype), 2.79, 1.79; NMV J40014 (only 4 of 5 specimens measured), 2.50, 1.51; 2.67, 1.66; 2.38, 1.51; 2.59, 1.59. Length range 2.38–2.79; height range 1.51–1.79; range of height as percent of length 60–64.

First Antenna (Figure 45a): 1st joint bare. 2nd joint with medial rows of minute spines. 3rd joint with spinous ventral bristle about half length of 4th joint, small dorsal bristle at midlength, and medial row of minute indistinct spines. 4th joint with 2 small bristles (1 ventral, 1 dorsal). Sensory bristle of 5th joint with 9 long stout proximal filaments (1 broken off near base on illustrated limb) followed by 3 slender shorter filaments with marginal spines and 1 small bare subterminal filament; stem distal to 3rd slender filament with marginal spines. 6th joint with short spinous medial bristle. 7th joint: a-bristle spinous, about same length as bristle of 6th joint; b-bristle shorter than sensory bristle of 5th joint, with 5 short spinous marginal filaments; stem of b-bristle distal to 5th filament with marginal spines; c-bristle almost twice length of bristle of 5th joint, with about 11 spinous marginal filaments and small bare subterminal filament. 8th joint: d- and e-bristles well developed, bare with blunt tips; f- and g-bristles about same length as c-bristle, each with about 9 pectinate marginal filaments and small bare subterminal filament.

Second Antenna: Protopodite with short spinous distal medial bristle (Figure 45c); small node with 2 minute spines present on dorsal margin at about length measured from anterior end (Figure 45b). Endopodite unjointed, with 4 proximal bristles (2 short bare, 1 long bare, 1 long spinous), and 1 very long bare terminal filament (Figure 45c). Exopodite: bristle of 2nd joint reaching past 9th joint, with 3 slender proximal dorsal spines, 3 proximal ventral hairs, followed by about 9 small slender ventral spines; bristle of 3rd joint with few proximal slender ventral spines and distal natatory hairs; bristles of joints 4–8 with natatory hairs; 9th joint with 4 bristles (1 short dorsal with few short hairs, 1 medium and 2 long with natatory hairs); joints 3–8 with slender basal spines increasing in length on distal joints; spine of 8th joint slightly longer than 9th joint; 9th joint with slender lateral spine (with bifurcate tip) about same length as spine of 8th joint; joints 4–8 (possible 2–8) with indistinct minute spines in vicinity of dorsal corner.

Mandible: Coxale endite with long marginal spines along edges but short spines on medial surface, and with 2 slender apical spines (right limb of USNM 193979 with small triangular process between apical spines (Figure 45d), but left limb without process (Figure 45e)); small unringed bristle with few spines present near base (Figure 45e). Basale (Figure 45e): dorsal margin with fairly long bristle (with indistinct short marginal spines) at midlength and 2 spinous terminal bristles (medial about length of lateral); ventral margin with 2 a-bristles (longer spinous), 1 small b-bristle with base lateral, 2 c-bristles with indistinct marginal spines (minute peg adjacent to longer bristle), and 1 long d-bristle with long proximal and short distal spines. Exopodite about length of dorsal margin of 1st endopodial joint, hirsute distally, with 2 bristles (distal almost half length of proximal). 1st endopodial joint with 4 bristles (1 minute bare, 1 short and 1 long with short spines, and 1 long with long proximal and short distal spines). 2nd endopodial joint: Ventral margin with spines and 4 slender equilength spinous bristles (2 single proximal, 2 paired distal); dorsal margin with about 17 bristles (5 long spinous, 3 medium spinous, 4 short with stout spines, and 5 short with indistinct slender spines) (not all bristles shown in Figure 45e); medial surface with indistinct rows of minute spines. 3rd endopodial joint with 3 stout pectinate claws (dorsal claw longer), 2 short, spinous, medial, ventral bristles, and 2 ringed lateral bristles (ventral long spinous, dorsal short).

Maxilla: Endite I with 10 bristles; endite II with 5 bristles; endite III with 1 proximal and 6 terminal bristles (Figure 46a). Coxale with plumose dorsal bristle (Figure 46b). Basale with slender bare dorsal bristle and short medial bristle at midwidth (Figure 46b). Exopodite hirsute, with 3 bristles (middle and proximal bristle spinous) (Figure 46b). 1st endopodial joint with dorsal spines, triangular cutting tooth, 2 slender subequal alpha-bristles with short marginal spines, and 2 beta-bristles (medial stout pectinate, lateral short slender with short marginal spines) (Figure 46b,c). 2nd endopodial joint with 4 spinous a-bristles, 3 pectinate b-bristles (outer ringed, middle unringed claw-like with few teeth, inner unringed claw-like), 2 pectinate c-bristles, and 3 stout pectinate claw-like d-bristles (outer ringed) (Figure 46d).

Fifth Limb: Epipodite with 57 plumose bristles (proximal bristle short). Protopodite with undulate tooth with rounded tip (Figure 46e). Endites I, II, and III with about 6, 4, and 7 bristles, respectively. 1st exopodial joint: Main tooth with small smooth proximal peg with pointed tip and 6 cuspate teeth (longest tooth with about 7 cusps excluding tip) (Figure 46f); bristle proximal to smooth peg with long proximal and short distal spines; anterior side of joint with row of 3 bristles (outer stout pectinate, middle with long proximal and short distal spines, inner short with few minute spines), and 1 stout bristle (with long proximal and short distal spines) near tooth of protopodite (Figure 46e). 2nd exopodial joint: With 6 pectinate, unringed, claw-like a-bristles (longest with about 12 cusps) (Figure 46f), 3 pectinate ringed b′-bristles (longest with about 19 cusps) (not shown), and 3 pectinate ringed b″-bristles (longest with about 20 cusps, of which proximal 8 shorter) (not shown); posterior side of joint with c-bristle with long proximal and short distal spines (Figure 46f); anterior side with small d-bristle with few short marginal spines (Figure 46e). 3rd exopodial joint (Figure 46g): Inner lobe with 1 proximal and 2 terminal bristles, all with long proximal and short distal spines (shorter of terminal bristles unringed, others ringed); outer lobe hirsute, with 2 ringed bristles with long proximal and short distal spines. 4th and 5th joints fused, hirsute, with minute rounded terminal process bearing spines, and 4 ringed bristles with long proximal and short distal spines (Figure 46g).

Sixth Limb (Figure 46h): With 4 short epipodial bristles with indistinct minute marginal spines. Endite I with 3 short, spinous, proximal, medial and 2 long terminal bristles with long distal spines; endite II with 2 short, spinous, proximal, medial and 2 terminal bristles (1 long with long proximal and short distal spines, 1 minute with long spines); endite III with 1 long, spinous, proximal, medial and 4 spinous terminal bristles; endite IV with 1 long, spinous, proximal, medial and 4 spinous terminal bristles. End joint with 16–19 bristles (2 or 3 small (with short spines) near anterior end, followed by 9 long, 3–5 short (all with long proximal and short distal spines), and 2 plumose posterior bristles); medial surface with long distal hairs; lateral surface with stiff spines along distal edge (absent near each end).

Seventh Limb: With total of 26–28 bristles: 10 or 11 bristles in proximal group (6 on comb side, 4 or 5 on peg side), each bristle with 4–6 bells; 16 or 17 bristles in distal group, all on terminal segment (8 on comb side, 8 or 9 on peg side), each bristle with 1–7 bells. Terminal comb with 3 long curved teeth (middle longer), and on each side 7 or 8 short teeth; 2 cup-like processes with 6–8 marginal teeth opposite comb (Figure 47a,b).

Furca (Figure 45g): Each lamella with 10 claws; claw 2 nonarticulated, remaining claws articulated; claw 5 very slightly broader than 4th claw but about same length; all claws with well-defined teeth along posterior edge, and most also with indistinct short hairs along anterior edge (teeth and hairs not shown); in general, teeth similar in size along each claw; claw 1 with distal medial teeth (not shown); right lamella anterior to left by width of base of claw 1, and with few spines along anterior edge proximal to claw 1.

Bellonci Organ (Figure 45h): Cylindrical with tapered tip and light amber-colored internal area (stippled in Figure 45h).

Eyes: Medial eye bare, with 2 light amber-colored areas (stippled in Figure 45e,f). Lateral eye larger than medial eye, with 29 ommatidia (amber-color in transmitted light), without black pigment between ommatidia (Figures 44a, 47c,d).

Upper Lip (Figure 47e,f): Anterior unpaired part with large glandular processes (7 posterior larger and with rounded tips); paired posterior part with small glandular processes along ventral edge and 1 larger slightly lateral process at posterior end; small lateral lobe with 1 glandular opening present proximally on each side near posterior end of paired part. (Lip of holotype somewhat opaque resulting in internal sclerites and other details being obscured.)

Genitalia (Figure 47g–j): Ring with attached spermatophore on each side of body anterior to furca.

Anterior of Body (Figure 45h): With prominent rounded anterior process between medial eye and upper lip.

Posterior of Body (Figure 47g): Evenly rounded, bare.

Y-Sclerite (Figure 47g,i): Somewhat obscured on holotype, and anterior end of left sclerite broken off; ventral branch not observed.

Eggs: Holotype with 18 eggs in marsupium (1 egg shown in Figure 44a); lengths of 3 typical eggs: 0.33, 0.34, 0.35.

COMPARISONS.—In the key to species of Skogsbergia presented in Kornicker (1992a:59), S. vivax keys to S. calyx Kornicker. It is considerably larger than that species (length of S. calyx 1.18–1.21 mm, compared to 2.38–2.79 mm for S. vivax). Also, the appendages of S. vivax differ as follows: 2nd antenna with longer bristle on the 2nd exopodial joint; 5th limb with shorter protopodial tooth, longer bristle on the 1st exopodial joint adjacent to the protopodial tooth, and more a-bristles on the 2nd exopodial joint; and 7th limb with more bristles.