Philomedes pentathrix Kornicker 1989

Philomedes pentathrix

Philomedes species A.—Kornicker, 1985:410–412 [part, except for specimens from sample DS-36 referred to P. lilljeborgii, herein].

ETYMOLOGY.—The species name is from the Greek penta (five) and thrix (hair.)

HOLOTYPE.—Adult female in alcohol, MNHN Os 158, Muséum National d'Histoire Naturelle, Paris, France.

TYPE LOCALITY.—BIOGAS I, Hors-Zone, R.V. Jean Charcot, West of Bay of Biscay, 47°30′12″N, 8°16′W, 2130 m, Sanders dredge, sample DS-09, August 1972.

PARATYPES.—BIOGAS I, R.V. Perle, sta Hors-Zone: sample DS-05, 1 juvenile; sample DS-09, 1 early instar; sample DS-14, 1 specimen. Sta 1: sample DS-11, 1 juvenile; sample DS-12, 2 juveniles; samples DS-13, 1 ovigerous female (USNM 157976) + 30 specimens. BIOGAS II, R.V. Jean Charcot, sta Hors-Zone: sample DS-33, 1 juvenile. Sta 1: sample DS-32, 1 adult male. Sta 2: sample DS-31, 1 adult male (USNM 193190) + 4 adult males + 12 specimens. BIOGAS III, R.V. Jean Charcot, sta 1: sample DS-35, 14 specimens; sample DS-38, 16 specimens. BIOGAS IV, R.V. Jean Charcot, sta 1: sample DS-61, 44 specimens; sample DS-62, 11 specimens; sample DS-63, 2 specimens; sample KR-37, 1 juvenile. Sta 2: sample DS-59, 1 ovigerous female (USNM 158591) + 1 juvenile. Sta 6: sample DS-52, 1 male. BIOGAS V, R.V. Jean Charcot, sta 2: sample DS-66: 2 specimens. BIOGAS VI, R.V. Jean Charcot, sta 1: sample DS-71, 1 specimen; sample CP-08, 3 specimens; sample CP-08a, 1 specimen; sample CP-09, 51 specimens; sample CP-09a, 64 specimens. Sta 2: sample DS-74, 1 specimen. Sta 6: sample DS-87, 1 specimen. BIOGAS VIII, R.V. Le Noroit, sta 1: sample K1 juvenile; sample KG-145, 1 instar II; sample KG-148, 1 adult female (USNM 193007) + 3 juveniles; sample KG-149, 1 juvenile; sample KG-156, 2 juveniles; sample KG-157, 1 adult female (USNM 193006) + 3 juveniles; sample KG-158, 1 ovigerous female (USNM 193005). BIOGAS XI, R.V. Jean Charcot, sta 1: sample CP-37: 3 specimens. Paratypes in Paris: MNHN Os 159–193.

ADDITIONAL MATERIAL.—BIOGAS IX, R.V. Capricorne, sta 2: sample KG-180, 1 instar (identification questionable).

DISTRIBUTION.—In and west of Bay of Biscay, 1560–3480 m.

DESCRIPTION OF ADULT FEMALE (Figures 39–41).—Carapace with prominent rostrum, broad incisur and truncate posterior (Figures 39, 40a, b); inferior rounded corner of rostrum with minute protuberance (not shown on Figure 39, but on Figure 40a).

Ornamentation: Carapace smooth with bristles along anterior, ventral, and posterior margin, and sparsely distributed on lateral surface.

Infold (Figure 40a, b): Broad along anterior and posterior and narrower ventrally; infold on rostrum with 21–23 bristles (mostly spinous and divided); 1 minute bristle on infold posterior to incisur; anteroventral part of infold with about 15 striae and 14 or 15 bristles along list; no bristles along middle part of ventral infold; posteroventral and posterior infold with numerous small bristles along raised list (about 69 bristles in groups of 1–4 bristles); 4 or 5 small bristles between list and posteroventral edge of caudal process; posteroventral edge of caudal process with 7 short pointed bristles.

Selvage: Lamellar prolongation with marginal fringe present along anterior, ventral and posterior margins; prolongation segmented along rostrum and incisur, and divided at inner end of incisur, long filaments with bases on lateral side of prolongation present below incisur.

Size: USNM 157976, length 2.19 mm, height 1.50 mm; USNM 158591, length 2.19 mm, height 1.51 mm; USNM 193005, length 2.21 mm, height 1.51 mm; USNM 193006, length 2.21 mm, height 1.51 mm; USNM 193007, length 2.22 mm, height 1.49 mm.

First Antenna (Figure 40c): 1st joint spinous. 2nd joint spinous, with 2 spinous bristles (1 dorsal, 1 lateral, near ventral margin on illustrated limb, but usually near midheight). 3rd joint short with 3 spinous bristles (1 ventral, 2 dorsal). 4th joint with 5 bristles (4 ventral, 1 dorsal). Sensory bristle of 5th joint with 5 short marginal filaments and 5 terminal filaments; lateral surface of joint with spines forming rows. Bristle of short 6th joint with long proximal and short distal spines. 7th joint: a-bristle about longer than bristle of 6th joint, spinous; b-bristle about twice length of a-bristle, with 1 proximal and 4 terminal filaments; c-bristle about same length as sensory bristle of 5th joint, with 4 proximal and 5 terminal filaments. 8th joint: d- and e-bristles slightly longer than c-bristle, bare with blunt tips; f-bristle about same length as c-bristle, with 4 proximal and 5 terminal filaments; g-bristle longer than c-bristle, with 3 proximal and 5 terminal filaments. All filaments with minute terminal spine.

Second Antenna (Figure 40d): Protopodite with long distal hairs along dorsal margin, shorter distal spines along ventral margin, and short spines forming rows on medial surface near ventral and dorsal margins. Endopodite 2-jointed: 1st joint short with 6 bristles (5 proximal, 1 distal); 2nd joint elongate, with 3 or 4 spinous ventral bristles and long terminal bristle. Exopodite: 1st joint with minute, straight, medial, terminal bristle with tubular tip; bristles of joints 2–5 relatively short but longer than combined lengths of joints 2–9, with slender ventral spines, without natatory hairs; bristles of joints 6–8 long, with natatory hairs; 9th joint with 7 bristles (4 long with natatory hairs, 1 medium and 2 short with short marginal hairs); joints 2–8 with spines forming row along distal margin; joints 3–8 with small basal spines; basal spine of 8th joint about length of 9th joint; 9th joint with short lateral spine. Bristles of joints 6–8 and 4 long bristles of joint 9 broken on some specimens. Distribution of bristles on the 2nd endopodial joint of the 2nd antenna of 5 specimens is tabulated below.

USNM number Right limb Left limb

157976 5 5

158591 5 4

193005 5 4

193006 4 4

193007 4 5

Mandible (Figure 40e): Coxale endite bifurcate, spinous, with minute bristle near base. Basale: medial surface spinous, with 6 proximal bristles (3 unringed, pectinate; 3 ringed, spinous) near ventral margin; lateral surface with 3 or 4 spinous bristles with bases on or near ventral margin; ventral margin hirsute, with 1 proximal and 3 distal spinous bristles; dorsal margin with 5 distal spinous bristles. Exopodite more than length of 1st endopodial joint, hirsute distally, with 2 distal bristles (proximal of these only slightly longer than other). 1st endopodial joint with 4 ventral bristles and terminal dorsal spines forming row. 2nd endopodial joint: ventral margin with few spines and 6 bristles in 2 groups (3 in each group); dorsal margin with proximal spines and 9 bristles forming 2 groups near midlength of joint (3 bristles in proximal group, 6 in distal); medial surface with spines forming rows. End joint with 4 bristles and 3 claws with proximal ventral spines.

Maxilla (Figure 40f): Coxale with fringe of dorsal hairs and hirsute dorsal bristle; endite I broad, with 10 spinous and pectinate bristles; endite II narrow, with 6 spinous and pectinate bristles; endite III narrow, with 1 proximal bristle and 7 or 8 spinous and pectinate bristles (teeth on 2 of the pectinate bristles very large). Basale with 4 long terminal bristles (1 ventral, 1 medial, 2 dorsal); only medial bristle shown on illustrated limb). Exopodite small, with 3 bristles. 1st endopodial joint spinous, with 1 spinous alpha-bristle and 3 or 4 beta-bristles. End joint with 4 slender a-bristles with short marginal spines, 3 stout claws, and 5 bristles.

Fifth Limb (Figure 40g): Endite I with 5 bristles; endites II and III each with about 9 bristles. 1st exopodial joint: main tooth comprising 4 constituent teeth (proximal tooth small cone-like with 1 or 2 minute marginal teeth; next 2 teeth with marginal teeth; distal tooth large with triangular anterior part bearing 1 or 2 marginal teeth); spinous bristle proximal to cone-like tooth; anterior side with paired spinous bristles at midwidwidth, and short spinous bristle on process near outer edge. 2nd endopodial joint: inner curvature of large, flat, triangular tooth with 2 small teeth with digitate terminal edge; posterior side with 3 bristles forming group (comprising long middle bristle and smaller bristle on either side, all with small marginal teeth or spines), and 1 long stout proximal bristle with distal teeth along outer edge; anterior side with small spinous bristle at outer distal corner of large flat tooth. Outer lobe of 3rd exopodial joint with 2 hirsute bristles, inner lobe with 3 spinous bristles, 4th and 5th exopodial joints fused, hirsute, with total of 6 spinous brisles.

Sixth Limb (Figure 41a): 3 hirsute bristles in place of epipodite. Endite I with 2 spinous bristles; endite II with 3 or 4 spinous bristles; endite III and IV each with 1 medial spinous bristle and 8 or 9 terminal spinous bristles. End joint with 23–25 spinous and hirsute bristles. Endites and end joint with spines and hairs forming rows.

Seventh Limb (Figure 41b): Each limb with 21 bristles with marginal spines and 5–8 bells. Terminal bristles comprising 3 on peg side and 2 on comb side. Proximal bristles with 9 on peg side and 7 on comb side. Terminus with 2 pegs and comb of 13 flanged teeth with minute proximal tooth on each side; comb teeth increasing in length toward middle of comb.

Furca (Figure 40h): Each lamella with 10 claws; claws 1–5 primary, claws 6–10 secondary, but distinction not well defined on some lamellae; teeth present along posterior margins of claws; medial tooth distal to midlength of claw 1 larger than others; teeth of claws 1–5 triangular tooth-like, teeth of claws 6–10 slender, spine-like; hairs present at base of claws and following claws; few distal hairs along anterior edge of right lamella; claw 1 of right lamella slightly anterior to that of left lamella.

Bellonci Organ (Figure 41c): Elongate, with suture near midlength and rounded tip.

Eyes: Lateral eye minute, indistinct, with minute amber globules (ommatidia?) (Figure 40i, j), eye not observed on some specimens. Medial eye well developed, with light amber pigment (Figure 41c).

Upper Lip (Figure 41c): Hirsute, with few glandular processes at anterior tip.

Anterior of Body (Figure 41c): Cone-like projection with small process at tip present between upper lip and medial eye.

Posterior of Body (Figure 40h): Posterior margin dorsal to furca with long hairs; short spines on posterodorsal bulge just above dorsal end of girdle.

Y-Sclerite (Figure 42): With ventral branch near midlength.

Eggs: USNM 158591, 193005 with 2 eggs; USNM 157976 with 7 eggs.

DESCRIPTION OF ADULT MALE (Figure 42): Carapace more elongate than that of adult female, with shallower incisur, and with concavity between posterior margin of valve and dorsal margin of caudal process (Figure 42a).

Infold: Not examined in detail but in general similar to that of female.

Selvage: Similar to that of female.

Size: Five specimens from BIOGAS II, sample DS-31: USNM 193190, length 2.68 mm, height 1.45 mm; length 2.73 mm, height 1.40 mm; length 2.73 mm, height, 1.38 mm; length 2.61 mm, length 1.44 mm; length 2.62 mm, length 1.34 mm.

First Antenna (Figure 42b): 1st joint bare, 2nd joint spinous, with 2 spinous bristles (1 dorsal, 1 lateral). 3rd joint short, spinous, with 3 spinous bristles (1 ventral, 2 dorsal), 4th joint with 5 bristles (4 ventral, 1 dorsal), 5th joint triangular, wedged ventrally between 4th and 6th joints; sensory bristle with stout, elongate, proximal part bearing abundant thin filaments, and bristle-like distal part about same length as stout proximal part, with 1 proximal and 5 terminal filaments. 6th joint long, with spinous medial bristle about same length as joint. 7th joint: a-bristle slightly shorter than bristle of 6th joint; b-bristle reaching past distal end of sensory bristle of 5th joint, with marginal filaments (tip broken off both limbs of specimen examined); c-bristle long, stout, with numerous filaments, broken. 8th joint: d- and e-bristles reaching well past distal end of sensory bristle of 5th joint, bare with blunt tips; f-bristle long, stout, with numerous filaments (broken on specimen examined); g-bristle broken on both limbs of specimen examined.

Second Antenna (Figure 42c): Protopodite bare. Endopodite 3-jointed: 1st joint with 6 bristles (5 proximal, 1 distal); 2nd joint elongate, with 3 short, spinous, ventral bristles; 3rd joint elongate, reflexed on 2nd, with slender proximal bristle, 2 small subterminal bristles, and tip with 6 ridges. Exopodite: 1st joint elongate, with distal spines along ventral margin and minute medial bristle on distal margin; 2nd joint about length of 1st, with terminal bristle reaching 6th joint, with 6 or 7 small ventral spines at midlength, no hairs; 3rd joint about twice length of 2nd; bristles of joints 3–8 long, with natatory hairs, no spines; 9th joint with 6 bristles (4 long, 2 short, all with natatory hairs); joints 2–8 with minute spines forming row along distal margins; joints 4–7 with small basal spine.

Mandible (Figure 42d): Coxale endite represented by small process terminating in 2 long spines. Basale: medial surface spinous, 5 bristles (3 unringed, 2 ringed) in proximal ventral corner, and 1 spinous bristle proximal to midlength of joint; lateral surface with 3 spinous lateral bristles near ventral margin; ventral margin with 1 proximal and 3 distal spinous bristles; dorsal margin with 5 distal spinous bristles. Exopodite reaching midlength of dorsal margin of 1st endopodial joint, hirsute distally, with 2 terminal bristles (outer same length or length of inner). 1st endopodial joint with medial spines, 5 ventral bristles, and terminal dorsal spines forming row. 2nd endopodial joint: medial surface and dorsal and ventral margins with long spines forming rows; ventral margin with 6 bristles forming 2 groups (3 bristles in each group); dorsal margin with 9 bristles near midlength. End joint with 4 bristles and 3 claws bearing proximal ventral spines.

Maxilla: Limb reduced. Coxale with fringe of dorsal hairs and hirsute dorsal bristle; endites I–III with weakly ringed bristles. Basale with 2 dorsal, 1 ventral, and 1 medial bristle on distal margin. Exopodite with 3 ringed hirsute bristles (2 long, 1 short). 1st endopodial joint with 1 spinous alpha-bristle and 3 beta-bristles. End joint with weakly developed claws and bristles.

Fifth Limb (Figure 42e–g): Endite I with 4 bristles; endite II with 7 bristles; endite III with about 7 bristles (3 unringed, broad). 1st endopodial joint with 4 unringed bristles (1 of these long, broad), and several ringed bristles. 2nd exopodial joint with 1 long, broad, unringed bristle with long marginal hairs, and several ringed bristles. 3rd exopodial joint with 2 stout hirsute bristles on outer lobe and 2 slender bristles on inner lobe. 4th and 5th exopodial joints fused, hirsute, with 5 slender ringed bristles. Epipodite with 53 bristles.

Sixth Limb (Figure 42h): Three or 4 hirsute bristles in place of epipodite. Endite I with 3 bristles; endite II with 1 medial and 2 terminal bristles; endite III with 1 medial and 8 terminal bristles; endite IV narrower than endite III, with 1 medial and 6–8 terminal bristles. End joint with 19 spinous and hirsute bristles. Endites and end joint with spines and hairs forming rows.

Seventh Limb (Figure 42i): Each limb with 14 or 15 bristles with 4–7 bells, no marginal spines. Terminal bristles comprising 3 on peg side, 2 on comb side. Proximal bristles with 5 or 6 on peg side and 4 on comb side. Terminus with 2 pegs and comb of about 11 teeth; comb teeth increasing in length towards middle of comb.

Furca (Figure 42j): Each lamella with 9 claws decreasing in length posteriorly, but claws 6–9 much smaller than claw 5. Claw 1 without large medial teeth as on claw of female. Teeth of claws 1–5 slender, tooth-like, teeth of claws 6–9 spine-like. Hairs present at bases of claws and following claws; claw 1 of right lamella anterior to claw 1 of left lamella; few distal hairs along anterior edge of right lamella.

Bellonci Organ (Figure 42k): Elongate with suture near midlength and rounded tip.

Eyes (Figure 42k): Lateral eye well developed, with about 20 ommatidia and black pigment. Maximum length of medial eye about same as maximum diameter of lateral eye, with brown pigment.

Upper Lip (Figure 42k): With small anterior process.

Genitalia: Copulatory lobes small.

Anterior of Body (Figure 42k): With broad anterior projection at midheight, unlike small anterior process of female.

Posterior of Body (Figure 42j): Posterior margin with long hairs.

Y-Sclerite (Figure 42j): Similar to that of female.

PARASITES.—BIOGAS XI, CP-37, juvenile with cyproniscid isopod.

COMPARISONS.—The new species P. pentathrix is closely related to P. tetrathrix Kornicker, 1975a. It differs in the distribution of primary and secondary claws on the caudal furca. Each lamella of the furca of P. tetrathrix bears 4 primary claws, whereas, each lamella of P. pentathrix bears 5 primary claws. However, on some specimens of P. pentathrix the lengths of the claws decrease gradually along the lamella and the claws are not readily divisible into primary and secondary. Another difference is that the 2nd joints of many endopodites of the 2nd antennae of the adult female of P. pentathrix bear 5 bristles, whereas, endopodites with 5 bristles were not observed on P. tetrathrix. Also, the 7th limbs of female P. pentathrix bear 21 bristles compared to 26–33 bristles for P. tetrathrix. The lengths of carapaces of female P. pentathrix (2.19–2.22 mm) are shorter than those of P. tetrathrix from the South Atlantic (2.61–2.78 mm) reported by Kornicker (1975a:257), but are longer than a female P. tetrathrix (1.91 mm) from the South Pacific near the Strait of Magellan (Kornicker, 1975a:257). The new species also resembles P. linkoi Chavtur, 1983, but differs in having 4 or 5 bristles intead of 2 on the 2nd endopodial joint of the 2nd antenna.

MATERIAL.—BIOGAS VI, R.V. Jean Charcot, sta 4, sample CP-17: 1 A-1 male (USNM 193251).