Philomedes tetradens Kornicker & Caraion 1977

Philomedes tetradens

HOLOTYPE.—USNM 150289, 1 adult female, length 2.16 mm; in alcohol and on slides.

TYPE-LOCALITY.—Station X043.

ETYMOLOGY.(—The specific name is from the Latin tetra (four) and dens (tooth), in reference to the 4 teeth on the margin of the caudal process of the carapace.

PARATYPES.—“Grigore Antipa” 297, 1 juvenile female from station X043; USNM 156598. 1 adult female from station X043; USNM 156600, 1 adult female from station X070.

DESCRIPTION OF ADULT FEMALE (Figures 11, 12a,b,d–h. 13; Plate 5).–Carapace not calcified, with slightly convex dorsal margin, evenly rounded anterodorsal and posterodorsal corners, rounded anterior and posterior margins except for small caudal process (Figures 11, 12a,b,d,e; Plate 5a,b); ventral margin convex with small swelling near anterior end; distal margin of rostrum straight with protuberance on posterior corner (Figure 12a,d; Plate 5a,b); incisur broad with rounded inner end (Figures 11, 12d); distal end of caudal process with 4 or 5 teeth, upper tooth medial to valve edge.

Ornamentation: Surface smooth with widely scattered bristles with broad basal parts and shorter bristles without broad bases (Plate 5a–c); slender bristles form row along ventral margin and caudal process.

Infold: Broad along anterior and ventral margins and narrow along posterior margin dorsal to caudal process; infold on rostrum with 23 bristles, mostly spinous with bifurcate tip (Figure 12d); 1 small bristle present on infold posterior to inner end of incisur; anteroventral part of infold with about 11 striae and 13–15 short bristles; infold along ventral margin bare; list paralleling inner margin of posteroventral and posterior infold with about 67 minute bristles in groups of 1 to 6 bristles (Figure 12b,e; Plate 5d); “pocket” present in infold of caudal process; anterior margin of pocket with 6–8 small bristles (Figure 12b,e); outer edge of caudal process with 5 short bristles (Figure 12b,e).

Selvage: Lamellar prolongation striate, fringed (Figures 11, 11a,d; Plate 5a).

Central Muscle Attachment Scars: Consisting of about 15 individual oval scars, and 3 elongate scars that may consist of 3 or 4 fused oval scars (Figure 11).

Size: USNM 150289, length 2.16 mm, height 1.46 mm; USNM 156598 length 2.20 mm, height 1.49 mm; USNM 156600, valve torn, length about 2.2 mm.

First Antenna (Figure 12f): 1st joint: cluster of lateral spines in distodorsal corner. 2nd joint: long spines forming 7 rows along dorsal margin, a single row proximally on medial surface, and a single row on lateral surface in distodorsal corner; 3 bristles (1 dorsal, bare or with short marginal spines, 1 ventral and 1 lateral, each with long spines near middle). 3rd joint: 4 bristles (1 ventral, 3 dorsal). 4th joint: 5 bristles (1 dorsal, 4 ventral). 5th joint: sensory bristle with 5 short marginal filaments and 4 short terminal filaments including tip. 6th joint: medial bristle about two-thirds length of a-bristle. 7th joint: a-bristle with long middle and short distal spines; b-bristle longer than a-bristle, with 0 or 1 marginal filaments and 3 or 4 short terminal filaments including stem; c-bristle about same length as sensory bristle of 5th joint, with 3–5 marginal filaments and 5 terminal filaments including stem. 8th joint: d- and e-bristles bare, about same length as c-bristle; f-bristle about same length as c-bristle, with 4 marginal filaments and 4–5 terminal filaments including stem; g-bristle about same length as c-bristle, with 3 marginal filaments and 5 terminal filaments including stem.

Second Antenna: Protopodite bare. Endopodite 2-jointed (Figure 12g): 1st joint with 5 short, bare, proximal bristles, and 1 short distal bristle with few short hairs; 2nd joint with 1 recurved bare terminal bristle and 4 ventral bristles (proximal of these long, with long middle and short distal spines; remaining bristles short with short marginal spines). Exopodite: 1st joint with short medial spine; joints 2–8 with short spines forming row near terminal margin and short basal spines increasing in length on distal joints; basal spine on joint 8 one-half to three-fourths length of ventral margin of 9th joint; bristle of joint 2 reaching well past 9th joint and with 2 minute ventral spines near middle of bristle; bristles of joints 3–5 bare, slightly longer than bristle of 2nd joint; bristles of joints 6–8 and 4 long bristles of 9th joint with natatory hairs; 9th joint with 2 short, dorsal bristles with long middle and short distal hairs, and 1 very short bare dorsal bristle; 9th joint without lateral spine. No natatory bristles broken on adult females USNM 150289 and 156598.

Mandible (Figure 12h): Coxale endite bifurcate, spinous, with minute bristle near base. Basale: medial side with 6 proximal bristles near ventral margin (3 unringed, pectinate; 3 ringed, with long middle and short distal spines); lateral side with 5 bristles near ventral margin (proximal 1 or 2 of these have bases on ventral margin); distal ventral margin with 2 bristles, all with long middle and short distal spines; dorsal margin with 4 bristles in addition to 2 terminal bristles; medial surface with long hairs forming rows on ventral half. Exopodite hirsute with 2 subterminal bristles (proximal bristle longer than distal bristle, with long middle spines and short distal spines; distal bristle with few long middle spines). Endopodite: 1st joint with 4 ventral bristles and few short spines along dorsal margin; 2nd joint with 2 groups of 6 bristles each on dorsal margin and 2 groups of 3 distal bristles each on ventral margin (1 of the bristles considered here to be in anterior group actually between the groups), medial surface of 2nd joint spinous; end joint with 3 claws and 3 bristles.

Maxilla (Figure 13a): Precoxale with epipodial fringe along dorsal margin. Coxale with stout plumose dorsal bristle. Endite I with 10 bristles; endite II with about 5 bristles; endite III with about 10 bristles. Basale: ventral margin with 2 long bristles (1 medial, 1 lateral), medial side with 3 short slender bristles near dorsal margin. Exopodite: 3 bristles (2 long, 1 short). Endopodite: 1st joint spinous, with I spinous a-bristle and 4 β-bristles, some with short marginal spines; end joint with 3 pectinate clawlike bristles in addition to about 8 slender ringed bristles.

Fifth Limb (Figure 13b): Epipodial appendage with 56 bristles. Exopodite: 1st joint with 1 short stout spinous bristle in outer distal corner, anterior bristles obscure on limb examined, main tooth with 3 pectinate teeth and proximal bare peg, anterior part of distal tooth with 2 large prongs, spinous bristle present proximal to peg: 2nd joint with large squarish tooth with 2 digitate teeth on inner margin, posterior side with proximal bristle (bristle not reaching tip of middle of 3 distal bristles), and usual group of 3 distal bristles (middle bristle much longer than bristle on each side); 3rd joint with 2 bristles on outer lobe and 3 on inner lobe; 4th and 5th joints fused, with 6 spinous bristles.

Sixth Limb (Figure 13c): Epipodial appendage consisting of 4 or 5 hirsute bristles; endite I with 2 medial and 1 terminal bristle; endite II with 1 medial and 3 terminal bristles; endites III and IV with 1 medial and 8 terminal bristles; end joint with 34–41 bristles.

Seventh Limb (Figure 13d): Proximal group with 4 bristles (2 on each side); terminal group with 5 bristles (2 on comb side, 3 on peg side); each bristle with up to 7 bells and distal marginal spines; terminus with comb of about 12 teeth opposite 6 or 7 pegs.

Furca: Each lamella with 10 claws similar to furca of P. lilljeborgii (see Skogsberg, 1920:409, fig. 15).

Rod-shaped Organ: Elongate, 1- or 2-jointed with rounded tip.

Eyes: Medial eye bare; lateral eye not observed.

Upper Lip: Helmet-shaped, hirsute, with anterior processes.

Anterior and Posterior of Body: Rounded knob present between medial eye and upper lip. Posterior of body just dorsal to furca hirsute.

Y-Sclerite: Typical for genus.

Genitalia: Small oval structure anterior to anus.

DESCRIPTION OF A–1 FEMALE.—Carapace similar to that of adult female, except edge of caudal process with 5 teeth (Figure 12c).

Size: “Grigore Antipa” 297, length 1.88 mm, height 1.22 mm.

First Antenna: Not examined in detail but in general similar to that of adult female.

Second Antenna: 2nd endopodial joint with 1 long and 2 short ventral bristles and 1 recurved terminal bristle; bristles of exopodite short, bare: remaining part of limb not examined in detail.

Mandible: Dorsal margin of basale with 5 bristles, remaining part of limb not examined in detail but in general similar to those of adult female.

Fifth and 6th Limbs: Not examined in detail but in general similar to those of adult female.

Seventh Limb: Each limb with 4 proximal and 5 distal bristles; each bristle tapering dis tally (a juvenile character); terminus not examined in detail but in general similar to that of adult female.

Furca: Each lamella with 9 claws, otherwise similar to lamellae of adult female.

Rod-shaped Organ, Eyes, Upper Lip, Anterior and Posterior of Body: Not examined in detail, but similar in general to those of adult female.

COMPARISONS.—The new species P. tetradens differs from P. bonneti in having 4 or 5 teeth on the outer edge of the caudal process rather than the more numerous (6–10) much smaller digitations on the edge of the caudal process of P. bonneti. The protuberance on the posterior corner of the rostrum on the carapace of P. tetradens is much longer than that of P. bonneti. The dorsal margin of the basale of the mandible of P. tetradens bears 6 bristles compared to 5 on P. bonneti. The end joint of the 6th limb of P. tetradens bears more bristles than that of P. bonneti. Comparisons of some characters of adult females of P. tetradens, P. bonneti, and P. lilljeborgii are as follows:

Euphilomedes Poulsen, 1962

Three species of Euphilomedes were collected: E. asper (Müller, 1894), E. sinister pentathrix, new subspecies, and E. schornikovi, new species. A supplementary description is also given of E. sinister sinister based on specimens collected in Plymouth Sound, England, by Dr. Eric Robinson. The other species of Euphilomedes previously collected off west Africa are: E. africanus Klie, 1940, and E. kornickeri Hartmann, 1974.