“Philomedes ramus, new species
Figures 168-170
HOLOTYPE.—USNM 135047, adult female, length 3.21 mm. Appendages on slide, some in alcohol; 1 valve in alcohol, other gold-plated on slide.
TYPE-LOCALITY.—Vema Cruise 17, station 17- V-8.
ETYMOLOGY.—The specific name is derived from the Greek "ramus" [ = branch] and refers to the bifurcate tips of some of the terminal pegs on the 7th limbs.
MATERIAL.—Holotype.
DIAGNOSIS.—Posterior with small caudal process; length about 3.21 mm; surface with abundant short hairs (bristles).
First antenna: 2nd joint with 3 bristles, 1 ventral, 1 dorsal, 1 lateral.
Second antenna: 1st endopodial joint with 6 bristles, 2nd with 2.
Mandible: Dorsal margin of basale with 3 bristles.
Seventh limb: Each limb with about 20 bristles; terminus with 1 short slightly curved inner peg and 3 longer pegs with bifurcate tips.
Furca: Each lamella with 11 claws.
Lateral eye: Small, hirsute, with 2 faint ommatidia.
DESCRIPTION OF ADULT FEMALE.—Carapace with prominent rostrum and broad incisur; posterior with small caudal process; anterior and inferior corners of rostrum angular, margin between corners linear; minute protuberance present on inferior corner of rostrum.
Ornamentation: Carapace with abundant short stout bristles and scattered longer bristles on lateral surfaces and along margins.
Infold: Infold on rostrum with 18 plumose bristles parallel to posterior and ventral valve margins, and 3 bare bristles along ventral margin; 1 small bare bristle present below inner end of incisur; anteroventral part of infold with about 10 striae, and with 15 spinous bristles along list; no bristles present along middle part of ventral infold; posteroventral and posterior infold with about 56 bristles along inner margin in groups of 1 to 4 bristles (bristles along inner margin of posterior infold quite long); infold of caudal process with cresent-shaped depression (4 to 8 small bristles present along inner margin of depression, 2 bristles along outer margin near valve edge).
Selvage: Lamellar prolongation with marginal fringe present along anterior and ventral margins; prolongation with typical segmentation along rostrum and incisur; prolongation discontinuous at inner end of incisur; long bristles with bases near middle of lamellar prolongation present on prolongation along anteroventral margin of valve.
Size: USNM 135034, length 3.21 mm, height 2.32 mm.
First antenna: 1st joint with faint spines forming clusters along ventral margin; 2nd joint with spines forming clusters along dorsal margin and on medial surface, and 3 bristles, 1 ventral, 1 dorsal, 1 lateral, all with long proximal and short distal spines; 3rd joint with 3 bristles, 1 ventral, 2 dorsal; 4th joint with 5 bristles, 1 dorsal, 4 ventral; sensory bristle of 5th joint with 5 proximal and 4 terminal filaments; 6th joint with short medial bristle with long spines near middle and short spines distally. Seventh joint: a-bristle about twice length of bristle of 6th joint and with long proximal and short distal spines; b-bristle slightly shorter than sensory bristle and with 1 proximal and 3 terminal filaments; c-bristle with 5 proximal and 3 terminal filaments. Eighth joint: bare d- and e-bristles about same length as b-bristle; f- and g-bristles with about 4 proximal and 4 terminal filaments.
Second antenna: Protopodite bare. Endopodite 2-jointed: 1st joint with 6 bare bristles, 5 proximal, 1 distal; 2nd joint with 2 bristles, 1 ventral with wreaths of long spines, 1 terminal recurved, bare. Exopodite: 1st joint with short medial spine; bare bristle on 2nd joint reaching considerably past 9th joint; bristles of joints S to 5 bare, complete; bristles of 6th to 8th joints and long bristles of 9th joint broken; small basal spines present on joints 2 to 8; short spines forming row present on distal margins of joints 3 to 8; 9th joint with 7 bristles, all except 2 short bristles broken (longest of short bristles with long marginal hairs).
Mandible: Coxale endite large, pectinate, with bifurcate tip; minute bristle present near base of endite. Basale: medial surface with 5 proximal bristles (3 pectinate, 2 spinous) and 1 spinous bristle nearer to middle; lateral surface with 5 short spinous bristles forming row near ventral margin (proximal of these could be considered to be on ventral margin); ventral margin with 3 spinous distal bristles; dorsal margin with 3 bristles, 1 distal to middle, 2 terminal, all with long spines near middle and short spines distally. Exopodite about three-fourths length of dorsal margin of 1st endopodite joint, both with long spines near middle and short spines distally (outer bristle about three-fourths length of inner bristle). Endopodite: 1st joint with 4 ventral bristles and few terminal spines on dorsal margin; 2nd joint with spines forming clusters on medial and lateral surfaces; dorsal margin with spinous bristles forming roughly 2 groups, each with about 5 bristles (1 short spinous triaenid lateral bristle present between groups); ventral margin with 2 distal groups of bristles, each with 3 spinous bristles; end joint with 4 spinous bristles and 3 claws, medial claw with faint medial and lateral teeth along proximal part of concave margin.
Maxilla: 1st endite broad with 9 bristles; 2nd endite about three-fourths width of 1st endite and slightly longer, with 5 bristles; 3rd endite about same width as 2nd endite but twice its length, with 10 bristles. Coxale bristle stout plumose. Basale with 3 long bristles on distal margin. Endopodite: anterior margin of 1st joint spinous and with 1 spinous a-bristle; posterior margin with 5 terminal spinous 6-bristles; end joint with 4 a-bristles, 3 clawlike b- and d-bristles with few marginal teeth, and additional bristles. Short exopodite with 3 bristles, 2 long and 1 short.
Fifth limb: Epipodial appendage with 55 bristles; 3 endites present, 1st with 5 bristles; 2nd endite with about 6, 3rd with about 9. Endopodite (part of appendage obscure in mount): main tooth of 1st joint with 4 teeth, distal of these much stronger than others; process anterior to large tooth of main tooth rounded with secondary protuberance; spinous bristle present proximal to smallest of main teeth; 1 stout bristle present near outer corner of 1st joint; posterior side with usual 1 bristles; only 1 bristle present near middle of anterior distal margin; inner margin of large quadrate tooth of 2nd joint with 2 serrated teeth, each on individual process; 3rd joint with 3 spinous bristles on inner lobe and 2 on outer lobe; 4th + 5th joints with about 6 spinous bristles.
Sixth limb: 4 short spinous bristles present in place of epipodial appendage; 1st endite with 3 spinous bristles, 2 short medial, 1 long terminal; 2nd endite with 4 spinous bristles, 1 medial, 3 terminal; 3rd endite with 10 spinous bristles, 1 medial, 9 terminal; 4th endite with 9 or 10 spinous bristles, 1 medial, 8 or 9 terminal; end joint prolonged posteriorly and with 33 spinous and hirsute bristles; lateral and medial surfaces of end joint hirsute; lateral surfaces of endites 2 to 4 with long spines forming clusters.
Seventh limb: Each limb with total of 20 bristles, 5 in terminal group (3 dorsal, 2 ventral), remaining bristles scattered (8 or 9 dorsal, 6 or 7 ventral); each bristle with 3 to 5 bells; terminal comb with 14 or 15 alate teeth; terminus opposite comb with 1 short slightly curved inner peg and 3 longer pegs with bifurcate tips.
Furca: Each lamella with 11 daws decreasing in length posteriorly along lamella; claw 1 with teeth forming medial and lateral row; clump of long medial hairs present on claw 1 near base; hairs present at bases of claws and following claws.
Eyes and rod-shaped organ: Lateral eyes small, faint, with clusters of long hairs; medial eye pigmented, more than twice diameter of lateral eye. Rod-shaped organ elongated, 1- jointed with rounded tip.
Upper lip: Lip hirsute with minute spines on anterior tip; unpaired process present between lip and medial eye.
Posterior: Rounded with hairs forming clusters along ventral part.
Epizoa: Stemmed cuplike protistans abundant on body and appendages.
COMPARISONS.—The new species, P. ramus, differs from known species in having bifurcate tips on some of the terminal pegs of the 7th limb. The carapace is about 0.5 mm longer than species of Philomedes previously described herein.
DISTRIBUTION.—This species was collected at only one locality in the Subantarctic-to-55° region west of Chile at a depth of 3219 m.”
(Kornicker 1975A, p.277-281)
