Eurypylus darwinensis Kornicker 1996

Eurypylus darwinensis

ETYMOLOGY.—Named for Darwin, Australia.

HOLOTYPE.—Ovigerous female on slide and in alcohol, AM P45366.

TYPE LOCALITY.—Darwin, Australia, sta JLB Darwin 304, East Point, 22 Aug 1982, intertidal washings of algae and substrate.

PARATYPES.—Type locality: AM P45368, adult male on slide and in alcohol.

DISTRIBUTION.—Known only from type locality.

DESCRIPTION OF ADULT FEMALE (Figures 40, 41).—Carapace oval in lateral view, with small caudal process (Figure 40).

Ornamentation (Figures 40, 41a): Surface rugose with U-shaped ridge just within dorsal, anterior, and ventral margins; dorsal arm of ridge terminates posteriorly in small knob-like process; a second U-shaped ridge well within outer ridge terminates posteriorly in poorly defined short vertical ridge; a short ridge present between posterior ends of the 2 U-shaped ridges terminates posteriorly in stout knob-like process extending past posterodorsal edge of valve. Surface of valves with abundant shallow fossae and minute papillae (latter not shown). Anterodorsal, anterior, and ventral margins of valves with numerous long bristles with bases (many bases broad) on inner side of margin; outside edge of caudal process with 8–10 long bristles with broad bases; bristles on lateral surface of valves sparse. Surface without gel-like coating.

Infold: Anterior infold with 1 small bristle near midheight of valve. Infold of caudal process with 5–7 small bristles (Figure 41a); posterior infold with 2 setal bristles near valve midheight (Figure 41a); inner margin of infold with 3 or 4 minute bristles in vicinity of caudal process.

Carapace Size (length (L), height (H), in mm): AM P45366 (holotype), L = 0.80, H = 0.66.

First Antenna (Figure 41b,s): 1st joint bare. 2nd joint with few indistinct dorsal spines and 1 spinous dorsal bristle. 3rd joint fused to 4th joint; 3rd joint with 2 bristles (1 ventral, 1 dorsal); 4th joint with few distal dorsal spines and 3 bristles (2 ventral, 1 dorsal). 5th and 6th joints fused; dorsal margin of 5th joint with numerous indistinct minute spines (these could be foreign but are present on both limbs of holotype); ventral bristle of 5th joint with 1 indistinct minute filament at proximal , minute terminal papilla, and rings in distal ; 6th joint with small medial bristle near dorsal margin. 7th joint: a-bristle about twice length of bristle of 6th joint; b-bristle about same length as a-bristle, with minute terminal papilla; c-bristle same length as bristle of 5th joint, with 2 minute filaments in proximal , minute terminal papilla, and rings in distal . 8th joint: d- and e-bristles about same length as c-bristle or very slightly shorter, bare with blunt tips; f-bristle shorter than c-bristle, with minute proximal filament, minute terminal papilla, and rings in distal ; g-bristle same length as c-bristle, with 3 minute proximal filaments, minute terminal papilla, and rings in distal . (Terminal papillae not shown on bristles of 7th and 8th joints.)

Second Antenna: Protopodite bare; dorsal margin with concavity near midlength (only holotype examined) (Figure 41e,r). Endopodite 1-jointed with 1 small proximal anterior bristle (Figure 41e) and no medial spines. Exopodite: 1st joint with small recurved terminal medial bristle; bristle of 2nd joint long, with 8–17 slender ventral spines in proximal and natatory hairs in distal ; bristle of joint 3 with 0–7 proximal ventral spines and natatory hairs; bristles of joints 4–8 with natatory hairs, no spines; 9th joint with 2 bristles (1 very short dorsal bare, 1 long ventral with natatory hairs); usual row of minute spines along distal edges of joints absent.

Mandible (Figure 41c,d): Coxale endite represented by small proximal ventral spine; coxale with short row of ventral spines. Basale: ventral margin with 6 bristles (4 medial, 2 lateral); dorsal margin with 1 minute distal spine-like bristle. Exopodite represented by minute indistinct process set inward from dorsal margin of basale (Figure 41d). 1st endopodial joint: distal medial surface with about 10 small spines forming single crescent-like row, and few small indistinct spines along distal edge near dorsal margin; ventral margin with stout ventral claw. 2nd endopodial joint with stout ventral claw. 3rd endopodial joint with minute ventral spine-like bristle and stout terminal claw (a minute dorsal spine-like bristle also may be present but not seen with certainty).

Maxilla: Endite I with 6 bristles (Figure 41f); endite II with 4 bristles (Figure 41g); endite III with 5 bristles (Figure 41h). Coxale with short dorsal bristle with short spines (Figure 41i). Basale with short bristle near base of exopodite (Figure 41i) and diaphanous thumb-like flap in vicinity of endite III (Figure 41h). Exopodite with 3 bristles (1 long, 2 short) (Figure 41i). 1st endopodial joint with few indistinct distal spines on anterior margin and pectinate alpha- and beta-bristles. 2nd endopodial joint with 2 a-bristles, 1 shorter c-bristle, and 5 pectinate end bristles.

Fifth Limb (Figure 41j): Epipodite with 31 bristles. Single endite with 1 short bristle. Exopodite: 1st joint with 2 bristles. Joints 2–5 fused, with 6 bristles (interpretation: 2nd joint with 2 bristles; 3rd joint with 1 long bristle on inner lobe and 1 short bristle on outer lobe; fused 4th and 5th joints with total of 2 bristles).

Sixth Limb (Figure 41k): With 2 closely spaced endites (endite I with 1 short bristle, and endite II with 1 short medial bristle and 1 longer terminal bristle (both endites also could be interpreted as a single endite with 3 bristles)). End joint with 10 anterior bristles with short marginal spines (all bristles ringed, but rings not shown) closely followed by 2 broad plumose bristles; posterior margin and medial surface near posterior margin with abundant long hairs.

Seventh Limb: Proximal group with 2 bristles, 1 on each side, each with 3 bells. Terminal group with 6 bristles, 3 on each side, with 2 and 5 bells. All bristles without marginal spines. Terminal segment with comb of about 8 teeth opposite comb of about 7 shorter teeth (exact number of teeth difficult to resolve) (Figure 41l).

Furca (Figure 41m,n): Each lamella with 6 claws; claws 1 and 2 primary and nonarticulated; claws 3–6 secondary and articulated. Posterior edges of claws 1 and 2 with stout proximal teeth and small distal teeth; anterior edges with slender distal spines. Claws 3–6 with small teeth along proximal parts of anterior and posterior edges and with smaller teeth distally along posterior edges. Right lamella with few spines along anterior edge; left lamella with numerous spines following last claw. Right lamella anterior to left lamella by width of base of claw 1.

Bellonci Organ (Figure 41o,q): Elongate, bare, with indistinct suture near midlength; proximal segment with thicker exoskeleton; distal segment broader and with rounded tip.

Eyes: Medial eye bare, with brown pigment (Figure 41o,q). Lateral eye easily visible, with 5 amber-colored ommatidia and brown pigment between ommatidia (Figure 41p–r).

Upper Lip (Figure 41s): Rounded.

Genitalia (Figure 41n): Round disk with sclerotized rim on each side of body anterior to furca.

Posterior of Body (Figure 41n): Bare, with part posterior to Y-sclerite projecting outward (posteriorly) from part ventral to Y-sclerite.

Y-Sclerite (Figure 41n): Typical for subfamily.

Number of Eggs: AM P45366 (holotype) with 4 eggs in marsupium and with smaller unextruded eggs; length of 1 extruded egg 0.181 mm.

DESCRIPTION OF ADULT MALE (Figures 42, 43).—Carapace differs from that of female in being more elongate and in having a slightly projecting rostrum (Figure 42).

Ornamentation (Figures 42, 43a–c): Surface rugose but with ridges less well defined than those of female; knob-like process in posterodorsal corner of valve. Abundant surface papillae longer and more pointed than those of female (papillae shown in Figure 43b,c). In general, type and distribution of surface bristles similar to that of female (Figure 43a,c).

Infold: Anterior infold with minute bristle ventral to rostrum (Figure 43a). Infold of caudal process with 2 minute bristles (Figure 43b,c). Posterior infold with 2 setal bristles dorsal to caudal process (Figure 43b,c). Inner margin of infold with 1 or 2 minute bristles ventral to caudal process (Figure 43c).

Carapace Size (length (L), height (H), in mm): AM P45368, L = 0.76, H = 0.55.

First Antenna: Lost during dissection but of usual type, with abundant slender filaments on sensory bristle of 5th joint.

Second Antenna: Protopodite bare (Figure 43d); anterior half of dorsal margin straight or slightly concave (Figure 43n). Endopodite similar to that of female except with 2 proximal anterior bristles rather than 1 and with 2 medial rows of long hairs (Figure 43d). Exopodite: minute medial terminal bristle of 1 st joint straight, not curved as on female; bristle of 2nd joint with about 10 proximal ventral spines followed by natatory hairs; bristles of joints 3–8 with natatory hairs, no spines; 9th joint with 2 bristles (dorsal bristle short bare; ventral bristle long with natatory hairs); joints without usual row of minute spines along distal edges.

Mandible (Figure 43e,f): Coxale endite represented by minute spine near ventral margin; coxale without ventral spines. Basale: ventral margin with 6 small bristles (4 medial, 2 along ventral edge or slightly lateral); dorsal margin with 1 distal bristle (bristle missing on limb illustrated but socket present; length of bristle unknown). Exopodite absent. 1st endopodial joint: medial surface with numerous rows of minute spines; dorsal margin with row of minute terminal spines; ventral margin with 2 minute distal spines and 2 terminal bristles (1 small bare ringed and with base medial, 1 long stout ringed in distal and with minute proximal spines perpendicular to ventral edge). 2nd endopodial joint: medial surface with 2 rows of spines; dorsal margin at midlength with long slender bare ringed bristle; ventral margin with stout bare unringed terminal claw. 3rd endopodial joint with stout bare terminal claw and 3 bristles (1 dorsal minute indistinct, 2 ventral (1 small bare, other longer ringed and with minute spines perpendicular to ventral edge)). (Above description based on right limb; left limb missing from specimen, possibly lost during dissection.)

Maxilla (Figure 43g,h): Limb reduced. Endites with weakly formed bristles; bristles difficult to resolve (not all shown). Coxale with well-developed, indistinctly ringed dorsal bristle with few marginal spines. Exopodite with 3 well-developed bristles (1 long spinous, 2 short bare) (Figure 43h). Endopodite: 1st joint with weakly developed alpha- and beta-bristles; 2nd joint with 8 weakly developed bristles.

Fifth Limb (Figure 43i): Single endite with 1 short ringed bristle. Exopodite: 1st joint with 2 ringed bristles. Joints 2–5 fused, with 8 bristles (interpretation: 2nd joint with 3 bristles; 3rd joint with 1 bristle on inner lobe and 1 on outer lobe; fused 4th and 5th joints with total of 3 bristles). Bristle on inner lobe of 3rd joint and most bristles of 4th and 5th joints shorter than those of female.

Sixth Limb (Figure 43j–l): Left limb with single endite with 2 small bristles (Figure 43k); right limb with 2 endites (endite I with 1 small bristle, and endite II with 2 small bristles (Figure 43j)). End joint with 2 very long plumose anterior bristles, 4 bristles with short spines, and 6 or 7 plumose bristles (endite broken off in Figure 43l).

Seventh Limb (Figure 43m): Small, bare, thumb-like.

Furca (Figure 43m): Similar to that of adult female except with 2 instead of 4 secondary claws; left lamella with many spines following last claw.

Bellonci Organ (Figure 43n,o): Elongate with indistinct suture at midlength (a few weak sutures may be in distal half but not clearly resolved).

Eyes: Medial eye bare, with brown pigment (Figure 43n,o). Lateral eye about same size as medial eye, with 10 amber-colored ommatidia and brown pigment between them (Figure 43n).

Genitalia (Figure 43m): Lobes (1 with hook-like tip) on each side of body anterior to furca.

Upper Lip, Posterior of Body (Figure 43m), and Y-Sclerite (Figure 43m): Similar to those of female.

DISTRIBUTION.—Cosmopolitan at depths of 1–4500 m.

ASTEROPTERONINAE Komicker, 1981

Asteropterygion Komicker, 1981

TYPE SPECIES.—Asteropterygion thomassini Komicker, 1981b.

COMPOSITION.—Three species of this genus are known from the vicinity of Australia: Asteropterygion liguriae (Granata, 1915), A. magnum (Poulsen, 1965), and A. climax, a new species described herein.

DISTRIBUTION.—Cosmopolitan between the latitudes 34°N and 41°S. Known depth range is 0–363 m, and questionably to 1100 m.