Rhepoxynius heterocuspidatus (J. L. Barnard 1960)

Rhepoxynius heterocuspidatus (J.L. Barnard)

Paraphoxus heterocuspidatus J.L. Barnard, 1960:224–226, pls. 19, 20; 1964a: 103, 105; 1966a :89; 1969:196, 197.

DESCRIPTION OF FEMALE.—Female “k,” 4.69 mm: Head about 21 percent of total body length, greatest width about 77 percent of length, rostrum constricted, broad, moderately elongate, not reaching middle of article 2 on antenna 1. Eyes medium, clear of pigment, ommatidia large. Article 1 of peduncle on antenna 1 about as long as wide, about 2.7 times as wide as article 2, ventral margin with about 6 setules, weakly produced dorsal apex with 2 setules-setae, article 2 about 0.92 times as long as article 1, with widely spread but not reaching apex ventral cycle of 9 setae and 2 laterals, primary flagellum with 10 articles, about 0.7 times as long as peduncle, bearing 1 each short aesthetasc on articles 4–9, accessory flagellum with 8 articles. Antenna 2 with long ensiform process; spine formula of article 4 = 3–3–3, dorsal margin with notch bearing 4 long to short setae, ventral margin with 7 groups of 1–3 long to short setae, 2 ventrodistal long setae and 1 long facial spine, article 5 about 0.75 times as long as article 4, facial spine formula = 1, dorsal margin bearing 2 sets of 2 short setae, ventral margin with 5 sets of 1–2 long to short setae, 3 ventrodistal long to short spines, one of these subdistal facial spine; flagellum about as long as articles 4–5 of peduncle combined, with 12 articles.

Epistome without anterior cusp. Mandibles with weak palpar hump, right incisor with 3 teeth, third tooth very apical, left incisor with 3 humps in 2 branches, right lacinia mobilis bifid, like 2 rakers fused, left lacinia mobilis with 4 teeth, middle teeth shortened; right rakers 9, plus 1 rudimentary, left rakers 11 plus 1 rudimentary; molars composed of short protrusions demarcated mainly by spines, right molar with 4 primarily short spines, no spine disjunct, left molar with 4 primarily medium spines, no spine disjunct, no molar with plume; palp article 1 short, article 2 with 1 very short inner apical seta and 1–2 other short inner setae, article 3 about 1.1 times as long as article 2, oblique apex with 11–10 spine-setae, basofacial formula = 0–1. Each outer lobe of lower lip with 1 cone. Inner plate of maxilla 1 ordinary, bearing 1 medium apical pluseta, 1 similar apicomedial seta, 2 apicolateral much shorter setae, palp article 2 with 1 apical marginal spine, 1 apicolateral, 2 apicomedial and 9 submarginal setae. Plates of maxilla 2 extending equally, outer broader than inner, outer with 2 apicolateral setae, inner with 2 medial seta. Inner plate of maxilliped with 1 thick short apical spine, 2 apicofacial setae, 4 medial setae, outer plate with 6 medial spines, no apicolateral setae or cusp, palp article 1 with 1 apicolateral seta, article 2 with 3 groups of 4 apicolateral setae, medial margin of article 2 moderately setose, article 3 with 6 scattered facial setae, 4 lateral setae, nail of article 4 absent, with 2 accessory setules.

Coxa 1 scarcely expanded apically, anterior margin weakly convex, main ventral setae of coxae 1–4 = 8–9–8–6, posteriormost seta of coxae 3–4 scarely shortened; anterior and posterior margins of coxa 4 divergent, posterior margin oblique, convex, posterodorsal corner rounded, posterodorsal margin short, concave, width-length ratio of coxa 4 = 13:15.

Gnathopods generally ordinary, but hands thin, width ratios on articles 5–6 of gnathopods 1–2 = 24:23 and 22:24, length ratios = 65:45 and 59 :42, palmar humps small, palms weakly oblique, article 5 of gnathopod 1 elongate, ovate, posterior margin rounded, long, article 5 of gnathopod 2 elongate, ovate, posterior margin rounded, short.

Pereopods 3–4 similar, facial setae formula on article 4 = 6 and 7 almost parallel to apex, on article 5 = 6 and 5, main spine of article 5 extending to M. 80 on article 6, article 5 with no proximoposterior spines, spine formula of article 6 = 6 + 8 and 6 + 8 plus no middistal seta, some spines especially long, acclivity on inner margin of dactyls of pereopods 3–4 weak, emergent setule short, midfacial pluseta short, position ordinary. Coxae 5–7 posteroventral seta formula = 2–10–1. Articles 4–5 of pereopods 5–6 of ordinary width, facial spine rows sparse to moderately developed, facial ridge formula of article 2 on pereopods 5–7 = 0–1–1, width ratios of articles 2, 4, 5, 6 of pereopod 5 = 64:52:50:20, of pereopod 6 = 68 :53 :38 :14, of pereopod 7 = 93:22:22:9, length ratios of pereopod 5 = 103:57:53:39, of pereopod 6 = 109:78:50:67, of pereopod 7 = 100:27:29:33, article 2 of pereopod 7 reaching apex of article 4, posterior margin with 3 large and 2 small serrations, articles 4 and 5 slightly expanded, both apices of articles 5 and 6 finely combed, lacking digital processes.

Posteroventral corner of epimeron 1 rounded, posterior margin weakly convex, corner without setule, anteroventral margin with 6 long setae, posteroventral face with 2 long setae set vertically. Posteroventral corner of epimeron 2 rounded, without setule sinus, posterior margin convex, facial setae = 10, posterior pair set vertically. Posteroventral corner of epimeron 3 weakly protuberant, with 2 long setae, posterior margin weakly convex, not shortened, with 1 setule notch, ventral margin with 3 setae all in posterior half but widely spread; epimera 1–3 without large seta on posterodorsal margin.

Urosomite 1 with lateral setule at base of uropod 1, face naked, articulation line almost complete, urosomite 3 unprotuberant. Rami of uropods 1–2 with articulate but tightly fixed apical nails, outer ramus of uropod 1 with 1 dorsal spine, inner with 1, outer ramus of uropod 2 without dorsal spines, inner with 1 dorsomedial spine, spines jewel-like. Peduncle of uropod 1 with 3 basofacial setae and 2 apicolateral spines, medially with 2 marginal setae and 1 apical enlarged spine. Peduncle of uropod 2 with 3 jewel-like dorsal spines, medially with 1 large apical spine, apicolateral corners of peduncles on uropods 1–2 without comb. Peduncle of uropod 3 without ventral spines, dorsally with 1 lateral spine, 1 medial setule, rami submasculine, inner extending to M. 100+ on article 1 of outer ramus, apex with 2 setae, medial margin with 2 setae, article 2 of outer ramus ordinary, 0.23, bearing 2 long setae, medial margin of article 1 with 3 setae, lateral margin with 2 acclivities, spine formula = 0, short setal formula = 1–1–1, long setae = 1–1–1. Telson especially long, length-width ratio = 15:11, almost fully cleft, each apex narrow, rounded, lateral acclivity broad, shallow, bearing ordinary lateral setule, seta next medial much longer than setule, midlateral setules diverse, larger of medium size.

Female “o,” 5.05 mm: Head about 22 percent of total body length, greatest width about 82 percent of length, rostrum constricted, narrow, short, scarcely exceeding apex of article 1 on antenna 1. Eyes medium, largely occluded with pigment, ommatidia ordinary. Article 1 of peduncle on antenna 1 about as long as wide, about 2.6 times as wide as article 2, ventral margin with about 7 setules, weakly produced dorsal apex with 2 setules-setae, article 2 about as long as article 1, with ventral, moderately confined cycle of 7 setae and 2 midlateral setae, primary flagellum with 11 articles, about 0.9 times as long as peduncle, bearing 1 each short aesthetasc on articles 5–10; accessory flagellum with 9 articles. Antenna 2 strongly ensiform; article 3 with apicodorsal spine; spine formula of article 4 = 3–3–3, dorsal margin with notch bearing 3 long to short setae, ventral margin with 6 groups of 1–2 long to medium setae, 2 ventrodistal long setae and 1 long facial spine, article 5 about 0.9 times as long as article 4, facial spine formula = 1, dorsal margin bearing 2 sets of short setae, ventral margin with 4 sets of 2 long to short setae, 3 ventrodistal long to medium spines set facially; flagellum about 1.3 times as long as articles 4–5 of peduncle combined, with 13 articles.

Epistome unproduced. Mandibles with weak palpar hump, right incisor with 3 teeth, third tooth very apical, left incisor with 3 teeth in 2 branches; right lacinia mobilis bifid, like 2 rakers fused, distal branch shorter than proximal; left lacinia mobilis with 5 short teeth, middle teeth not shortened; right rakers 10 plus 1 rudimentary, left rakers 10; molars composed of short protrusions, or plaques, demarcated mainly by spines, right molar with 4 primarily short spines plus 1 short spine weakly disjunct, left molar with 4 primarily medium spines plus 1 short spine scarely disjunct, no molar with plume; palp article 1 short, article 2 with 1 very short inner apical seta and 2 other short inner setae, article 3 about as long as article 2, oblique apex with 11 spine- setae, basofacial formula = 0–3. Lower lip lacking cones. Inner plate of maxilla 1 ordinary, bearing 1 medium apical pluseta, 1 similar apicomedial seta, 2 apicolateral much shorter setae, palp article 2 with 1 apical spine, 1 apicolateral, 3 apicomedial and 4 submarginal setae. Inner plate of maxilla 2 shorter than outer, outer much broader than inner, outer with 2 apicolateral setae, inner with 3 medial setae. Inner plate of maxilliped with 1 large short apical spine, 2 apicofacial setae, 4 medial setae, outer plate with 6 medial spines, no apicolateral setae or cusp, palp article 1 with 1 apicolateral seta, article 2 and 3 groups of 4 apicolateral setae, medial margin of article 2 strongly to moderately setose, article 3 with 5–6 facial setae, 2 lateral setae, nail of article 4 absent, with 2 accessory setules.

Coxa 1 scarcely expanded apically, anterior margin weakly convex, main ventral setae of coxae 1–4 = 6–6–6–4; posteriormost seta of coxae 3–4 shortened, anterior and posterior margins of coxa 4 divergent, posterior margin oblique, almost straight, posterodorsal corner rounded, posterodorsal margin short, concave, width-length ratio of coxa 4=19 :22.

Gnathopods generally ordinary, but hands thin, width ratios on articles 5–6 gnathopods 1–2 = 19:23 and 18:23, length ratios = 65:45 and 58:41, palmar humps small, palms weakly oblique, article 5 of gnathopod 1 elongate, ovate, posterior margin rounded-flat, long, article 5 of gnathopod 2 elongate, ovate, posterior margin rounded-flat, long.

Pereopods 3–4 similar, facial setae formula on article 4 = 5 and 6, parallel to apex on pereopod 4, less so on pereopod 3, on article 5 = 6 and 6, main spine of article 5 extending to M. 85 on article 6, article 5 with no proximoposterior spines, spine formula of article 6 = 6+7 and 6 + 8 and no middistal seta, some spines especially long; acclivity on inner margin of dactyls of pereopods 3–4 sharp, produced as tooth, emergent setule short, midfacial pluseta ordinary. Coxae 5–7 posteroventral seta formula = 1–7–1. Articles 4–5 of pereopods 5–6 of ordinary width, facial spine rows sparse to moderately developed, facial ridge formula of article 2 on pereopods 57 = 0–1–1; width ratios of articles 2, 4, 5, 6 of pereopod 5 = 66:52:49:21, of pereopod 6 = 92:55:37:15, of pereopod 7 = 97:25:23:11; length ratios of pereopod 5 = 103:55:50:45, of pereopod 6 = 102:77:53:69, of pereopod 7= 100:28:30:33; article 2 of pereopod 7 exceeding middle of article 4, posterior margin with 5 large serrations of even progression, articles 4 and 5 slightly expanded, both apices of article 6 and lateral of article 5 finely combed, lacking digital processes.

Posteroventral corner of epimeron 1 rounded, posterior margin convex, anteroventral margin with 6 long to medium setae, posteroventral face with 3 long setae set vertically. Posteroventral corner of epimeron 2 rounded, posterior margin convex, facial setae = 10, posteriormost pair set vertically. Posteroventral corner of epimeron 3 rounded, weakly protuberant, with 1 long seta, posterior margin weakly convex, with 2 setule notches, ventral margin face with 3 setae mainly posterior but widely spread.

Urosomite 1 with lateral setule at base of uropod 1, face naked, articulation line complete, urosomite 3 unprotuberant dorsally. Rami of uropods 1–2 with articulate but tightly fixed apical nails, outer ramus of uropod 1 with 1 dorsal spine, inner with 1, outer ramus of uropod 2 with no dorsal spines, inner with 1 dorsomedial spine, spines jewel-like. Peduncle of uropod 1 with 2 basofacial setae and 2 apicolateral spines, medially with 2 marginal spines and 1 apical enlarged spine. Peduncle of uropod 2 with 5 jewel-like dorsal spines, medially with 1 large apical spine, apicolateral corners of peduncles on uropods 1–2 without comb. Peduncle of uropod 3 without ventral spines, dorsally with 1 lateral spine, 1 medial setule, rami feminine, inner extending to M. 100 on article 1 of outer ramus, apex with 2 setae, medial and lateral margins with 3 and 1 setae; article 2 of outer ramus ordinary, 0.16, bearing 2 long setae, medial margin of article 1 with 4 setae, lateral margin with 3 acclivities, spine formula = 0, setal formula = 1–1–2–2. Telson especially long, length-width ratio = 9:7, almost fully cleft, each apex of medium width, protrudingly rounded, lateral acclivity deep, narrow, bearing ordinary lateral setule, seta next medial greatly elongate, mid-lateral setules diverse, larger of medium size.

Female “e,” 6.85 mm: Article 2 of antenna 1 with 8 setae widely spread towards apex; articles of primary flagellum = 10, accessory = 7. Facial formula on article 4 of antenna 2 = 3–4–6, article 5 = 3, article 5 about 0.9 times as long as article 4; articles of flagellum =11.

Left lacinia mobilis with 6 teeth, one of these also bifid; right rakers = 13 plus 2 rudimentaries; right molar with 6 spines; palp article 2 with 4 outer setae, palp 3 with 15 apical setae, basofacial count = 0–3.

Setal formula of coxae 1–4 = 10–11–10–9, coxa 2 also with 1 midposterior seta and 12 medial facial setae in row. Armament formulas of pereopods 3–4, article 4 = 10 and 12, article 5 = 7 and 7, article 6=7+8 and 7+10 and no middistal seta; dactylar acclivity sharp; teeth on article 2 of pereopod 7 = 6!, fourth tooth from ventral small and asymmetrical (illus.).

Armament counts on epimera, anteroventral = 19, posteroventral facial oblique = 3; epimeron 2=17; epimeron 3 posterior = 2 long, 2 short, posteroventral facial = 8, 2 pairs set vertically (fully facial).

Urosomite 1 lacking large facial setae; armament formulas on uropods, uropod 1 peduncle basofacial = 4, dorsolateral apex = 1 stout jewel, then proximal smaller jewel, then short seta, outer ramus = 1, inner = 2–1 (right and left); uropod 2 peduncle = 4–5 jewels, medial = 1 jewel, outer ramus = 1 jewel, inner = 1 jewel; inner ramus of uropod 1 extending to M. 70 only, with 2 apical and 1 medial setae, article 1 outer ramus lateral short setae = 1–1–1–1, long = 1–1–1–1, article 2 only 0.15 times as long as article 1; peduncle with no ventral spines, 1 setule dorsolaterally, 2 setules dorsomedially.

Telson aberrant, each lobe only with 2 apicolateral setules in acclivity but with normal mid- lateral dorsal setule pairs.

DESCRIPTION OF MALE (male “m,” 3.73 mm).—Rostrum similar to female. Article 2 of antenna 1 with 8 ventral setae, article 1 with medial pubescence, primary flagellum with 9 articles, 1 calceolus each on articles 1–6, aesthetascs more strongly developed. Articles 3–4 of antenna 2 with medial pubescence, facial spine formula on article 4 = 3–3–3, article 5 with 3 dorsal sets of male setae and 2 calceoli, ventrodistal apex with 2 thin spines; calceolus formula on flagellum = 1, 2, 3, 4, 5, 7, 9, 11, 13…n. Basofacial setal formula of article 3 on mandibular palp = 0–3. Article 2 of pereopods 5–7 narrower than in female; article 5 with 2 special male spines on pereopod 7. Epimera 2–3 broadened, posterior margin of epimeron 3 slightly shortened. Setal formulas: epimeron 1 anteroventral = 5, posteroventral = 2 vertical, epimeron 2 facial = 10 in 2 arcs, epimeron 3 posterior = 1–2 + 1 setule, ventral facial = 11, slightly staggered and facial. Spine formulas of uropods: uropod 1 peduncle apicolateral = 2, basofacial = 3, medial = 1 stout + 2 thin spines, uropod 2 peduncle dorsal = 3, medial = 1, dorsal spines on outer ramus of uropod 1 = 1, of uropod 2 = 0, inner ramus of uropod 1 = 1, of uropod 2 = 1, ventral spines on peduncle of uropod 3 = 0, spine formula on article 1 of outer ramus = 0, long setal formula =1X7 + 2–2–2, short setae = 0X8, 1–1. Telson not elongate, not broadened, distal setae shortened, 1 lateral setule, then 1 longer seta and 1 very short seta.

ILLUSTRATIONS.—Gnathopods very similar to those drawn for R. homocuspidatus. Pereopod 7 of female “e” is illustrated because of its typical cusp formation.

DISTRIBUTION.—California from Point Conception southward into Gulf of California as far as Bahí de Los Angeles and Bahía San Carlos, 0–64 m.