Euphilomedes ernyx Kornicker 1995

Euphilomedes ernyx

ETYMOLOGY.—From the Greek ernyx (sprout, shoot).

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

TYPE LOCALITY.—Slope 21, 36°57.40′S, 150°18.80′E, New South Wales, off Eden; depth 220 m.

PARATYPES.—Slope 21: USNM 194024, adult female on slide and in alcohol; partly dissected adult female with male and female cyproniscid isopod in marsupium; 2 juveniles (length 0.99 mm, height 0.69 mm; length 1.24 mm, height 0.92 mm).

DISTRIBUTION.—Slope 21, 220 m.

DESCRIPTION OF ADULT FEMALE (Figures 8–10).—Carapace oval in lateral view with projecting rostrum, shallow incisur, and evenly rounded posterior (Figure 8a). Inner end of incisur with internal sclerotized slightly curved finger-like “process” visible in transmitted light (crosshatched in Figure 8d) (“process” not previously reported in Myodocopa).

Ornamentation: Surface with abundant small round fossae with minute pustules between fossae (Figure 8a); about 35 larger fossae in vicinity of central adductor muscle attachments (Figure 8c); the larger fossae with beaded row of minute pustules along edge (Figure 8b); some smaller fossae with bristle emerging from center (Figure 8c); additional bristles along valve edge (Figure 8d,e); minute pustules along posterior edge of valve pointed, spine-like (Figure 8d–f).

Infold: Rostral infold of right valve with 14 or 15 undivided bristles in oblique row and 5 additonal undivided bristles along dorsal edge (Figure 8d); rostral infold of left valve with 13–16 undivided bristles in oblique row but without bristles along dorsal edge; narrow list with anterior end at ventral end of rostrum continues along ventral margin then broadens along posterior of ventral margin and posteroventral margin (Figure 8e,f); anteroventral infold with about 6 striae dorsal to list; 1 small bristle on anteroventral infold just ventral to incisur (Figure 8d) and 16 or 17 small bristles along anteroventral list; 15 minute bristles along broad posteroventral list (not all shown in Figure 8e,f; posterior infold of right valve with 4 small bristles and left valve with 1 bristle near inner margin (Figure 8e,f).

Selvage: Broad lamellar prolongation with marginal fringe present along edge of rostrum, ventral margin, and ventral half of posterior margin (prolongation not shown in Figure 8d but inner edge of selvage shown as striated band). Lamellar prolongation indistinctly divided at inner end of incisur near sclerotized “process.”

Central Adductor Muscle Attachments (Figure 8g): Comprising about 25 oval attachments (ends of attachments do not coincide with large round fossae on valve surface in vicinity of attachments).

Carapace Size (length, height in mm): Slope 21: holotype, 1.43, 0.99; specimen with cyproniscids 1.38, 0.94; USNM 194024, 1.37, 0.95.

First Antenna (Figure 8h,i): 1st joint spinous. 2nd joint spinous with 3 spinous bristles (1 ventral, 1 dorsal, 1 lateral). 3rd joint short, with 3 or 4 bristles (1 ventral, 2 or 3 dorsal). 4th joint with 6 bristles (4 ventral, 2 dorsal). Long bristle of 5th joint with 5 short proximal filaments and 4 or 5 long terminal filaments. 6th joint fused to 5th; medial bristle of 6th joint with few long proximal spines. 7th joint: a-bristle spinous; b-bristle with 2 proximal and 4 terminal filaments; c-bristle with 2 proximal and 5 terminal filaments. 8th joint: d- and e-bristles long bare; f-bristle with 2 proximal and 5 terminal filaments; g-bristle with 3 proximal and 5 terminal filaments. (Numbers given for terminal filaments include stem.)

Second Antenna: Protopodite bare (Figure 8j). Endopodite 2-jointed (Figure 8j): 1st joint with 7 bristles (6 short, 1 long); 2nd joint with long spinous ventral bristle near midlength and long terminal bristle. Exopodite: 1st joint with small straight medial bristle on distal edge; bristle of 2nd joint reaching just past 9th joint, with numerous slender ventral spines; bristles of joints 3–5 about to times length of bristle of 2nd joint, with stout ventral spines, no natatory hairs; on USNM 194024 bristles of joints 6–8 about 4 times length of bristle of 2nd joint, with stout ventral spines and no natatory hairs (?aberrancy), but on holotype bristles of joints 6–8 longer and with natatory hairs; 9th joint with 7 bristles (3 short bare, 4 long with slender proximal spines on both edges and distal natatory hairs); joints 2–8 with row of fairly long spines (about to length of joint) along distal edges.

Mandible (Figure 9a): Coxale endite stout, spinous, bifurcate, with small ringed bristle near base. Basale: dorsal margin with 5 bristles (distal shortest and bare, others with long proximal spines (not all spines shown)) near midlength, and 2 spinous terminal bristles; lateral surface with 5 spinous bristles with bases near ventral margin; medial surface with numerous rows of spines, 5 short bristles (3 stout unringed pectinate, 2 slender ringed spinous) in proximal ventral corner, and 1 ringed spinous bristle at midlength; ventral margin with 2 distal ringed spinous bristles. Exopodite more than length of dorsal margin of 1st endopodial joint, with spinous terminal process and 2 subterminal bristles (distal bristle bare and about length of spinous proximal bristle). 1st endopodial joint with 5 ringed ventral bristles (3 long with long proximal and short distal spines, 1 short with few short spines, 1 minute bare); dorsal margin with row of minute terminal spines. 2nd endopodial joint: ventral margin with distal spines, 2 ringed spinous subterminal bristles, and 3 ringed spinous terminal bristles; dorsal margin with 11 bristles (5 slender short proximal followed by 1 shorter with long spines, then 5 (4 long with long proximal spines, 1 short with short spines)). 3rd endopodial joint with short slender unringed dorsal claw (claw about length of longest claw), 2 stout claws with proximal ventral spines, and 4 slender ringed bristles. (Not all rings shown on bristles.)

Maxilla: Endite I with 9 spinous and pectinate bristles (Figure 9b); endite II narrow with about 6 spinous and pectinate bristles; endite III narrow with 1 proximal and about 7 terminal spinous and pectinate bristles. Coxale with dorsal fringe of long hairs and 5 bristles (4 slender bare, 1 stout plumose) (Figure 9d). Basale with 4 bristles on distal margin (2 dorsal bare (1 short, 1 long), 1 ventral, and 1 lateral (with long spines) at midwidth) (Figure 9d). Exopodite short with 3 bristles (1 short proximal, 2 long terminal). 1st endopodial joint with dorsal spines, 1 ringed alpha-bristle with long proximal spines, and 4 ringed beta-bristles (bare or with short spines). 2nd endopodial joint with 3 slender ringed a-bristles, 2 b-bristles (outer ringed spinous, inner unringed pectinate claw-like), 3 slender ringed c-bristles, and 3 d-bristles (outer ringed spinous, others unringed pectinate claw-like) (Figure 9c–e). (Not all rings or spines shown on bristles.)

Fifth Limb: Endite I with 6 spinous bristles (Figure 10a); endite II with about 10 bristles (Figure 10a); endite III with about 11 bristles. 1st exopodial joint (Figure 10b,d): triangular cusp anterior to main tooth bifurcate; main tooth with 4 pectinate cusps; spinous bristle present proximal to proximal cusp; anterior side of joint with 2 ringed bristles at midwidth (outer with long proximal spines), and small blunt bristle at outer corner (Figure 10d). 2nd exopodial joint (Figure 10b,d): flat tooth with long triangular distal inner projection with 2 small bifurcate cusps on inner curvature (Figure 10b); posterior side with long stout proximal and 3 distal bristles in row (middle bristle long spinous, flanking bristles short); minute posterior bristle near outer distal corner of flat tooth (Figure 10d). 3rd exopodial joint with 3 bristles (shortest bare, others with short spines) on inner lobe and 2 bristles (with long proximal hairs and short distal spines) on outer lobe (Figure 10c). 4th and 5th exopodial joints fused, hirsute, with total of 7 spinous bristles.

Sixth Limb (Figure 10e): With 4 spinous epipodial bristles. Endite I with 3 spinous bristles; endite II with 4 spinous bristles (1 proximal, 3 terminal); endites III and IV each with 9 spinous bristles (1 proximal, 8 terminal). End joint with 21 spinous and plumose bristles; medial surface hirsute.

Seventh Limb (Figure 10f,g): Each limb with 11 bristles with distal spines and 4–7 bells; terminal segment with 2 bristles on comb side and 3 on peg side; segments proximal to terminal segment with 6 bristles, 3 on each side. Comb with 13 or 14 alate teeth; side opposite comb with single bare peg with slightly bulbous tip.

Furca (Figure 9f): Each lamella with 11 claws; claw 3 short secondary, remaining claws decreasing in length along lamella; claws 1, 2, 4, and 5 with stout teeth along posterior edges; remaining claws with indistinct posterior teeth and some with few minute proximal anterior teeth; claw 1 with row of medial teeth, some stouter than those along posterior edge; teeth along posterior edges of claws 3 and 5 much slenderer than those on claws 1 and 2; right lamella anterior to left by width of base of claw 1 (see detail in Figure 9f).

Bellonci Organ (Figure 9g,h): Elongate with suture proximal to midlength, slightly broader distal to suture, then tapering to narrowly rounded tip with minute spine.

Eyes: Lateral eye minute, light amber colored, with about 5 minute ?ommatidia and several additional smaller cells (Figure 9g,h). Medial eye well developed, bare, with dark brown pigment (Figure 9g,h).

Upper Lip (Figure 9h): Projecting anteriorly, with ventral hairs but no visible glandular processes.

Genitalia: None observed.

Anterior of Body (Figure 9h): With small rounded anterior process about midway between medial eye and upper lip.

Posterior of Body (Figure 9f): Evenly rounded, bare except for few small spines near proximal end of furca.

Y-Sclerite (Figure 9f) With ventral branch.

Number of Eggs: No females from Slope 21 with eggs in marsupium.

Parasites: 1 specimen from Slope 21 with a male and female cyproniscid isopod in marsupium.

COMPARISONS.—Euphilomedes ernyx differs from previously described species of the genus in three characters: (1) each valve has a sclerotized finger-like internal “process” just ventral to the rostrum; (2) the dorsal margin of the basale of the mandible bears 7 bristles (other species have no more than 3); and (3) the dorsal margin of the coxale of the maxilla has 5 bristles (other species have 1). The furca of E. ernyx differs from that of E. corrugata in having only claw 3 secondary between main claws.

DISTRIBUTION.—This genus is cosmopolitan at depths of intertidal to 1015 m, but has not been collected in Antarctic or Arctic waters; the present report extends the known range of the genus south to about 38°S. The known depth range in the vicinity of Australia is 2–996 m (204–996 m in present collection).

MOTILITY.—The bristles of exopodites of the 2nd antennae of H. slatteryi and H. vatrax have natatory hairs and are therefore capable of swimming (both males and females known). The bristles of exopodites of the 2nd antennae of H. hapax, H. vortex, H. tenax, and H. felix are without distal natatory hairs, and therefore, are either not capable of efficient swimming or are nonswimmers (only females known).