Protophoxus munida, Taylor & Peart, 2023

Taylor, Joanne & Peart, Rachael A., 2023, A New Genus and Five New Species of Phoxocephalidae (Crustacea: Amphipoda) from the Eastern Tasman Sea, the Otago Shelf, and The Snares, New Zealand, Records of the Australian Museum (Rec. Aust. Mus.) 75 (4), pp. 567-600 : 588-590

Protophoxus munida sp. nov.

urn:lsid:zoobank.org:act:D657145C-E469-4E24-A915-69BDF6819435

Figs 15–16

Holotype: AM P39544 , female “q2”, 6.0 mm, Otago Shelf , New Zealand, 45°51'S 170°57'E, sand bottom, 132 m, P. K. Probert on RV Munida, 4 June 1974, MU74 /114.

Etymology. Named for the RV Munida, University of Otago research vessel; used as a noun in apposition.

Diagnosis. Eyes present. Head without constriction in dorsal view. Antenna 1 peduncular article 1 ventral apex not ensiform, peduncle article 2 shortened. Antenna 2 peduncle article 3 with robust setae, article 4 shortened with facial robust setae. Right mandible lacinia mobilis bifid. Maxilla 1 inner plate moderately large, outer plate with 11 multicuspidate robust setae. Maxilliped palp article 3 not produced. Posteroventral corner of coxae 1–3 without tooth. Gnathopods 1–2 carpus not cryptic. Gnathopod 2 similar sized to gnathopod 1, propodus with 1 robust seta near palmar corner. Pereopods 3–4 carpus setae placed near anterodistal margin. Robust setae forming dominant posterior element on pereopods 3–4 carpus. Pereopod 5 basis broad. Pereopod 6 basis anterior margin without setae, posterodistal corner not produced to form a lobe. Pereopod 7 merus, carpus, and propodus narrow; dactylus long. Urosome without basoventral setae. Epimera 1–2 without facial setae. Uropods 1–2 rami never fully spinose. Uropod 1 peduncle with displaced robust seta on medial and lateral apices. Uropod 2 peduncle only with robust setae. Uropod 3 outer ramus article 2 with 2 long apical setae; inner ramus medium length, about 0.5 × the length of outer. Telson deeply cleft, apically with 1 robust seta per lobe, marginally without setae on each side, without lateral robust setae.

Description. FEMALE, based on AM P39544, female, holotype, “q-2”, 6.2 mm.

Head: Eyes medium, largely free of pigment. Head about 0.18 × body length, greatest width about 0.75 × length; rostrum not constricted, broad, reaching middle of peduncle article 2 on antenna 1. Antenna 1 peduncle article 1 1.6 × as long as wide, about 2 × as wide as article 2, ventral margin with about 8 setules, weakly produced dorsal apex with 3 setae; article 2 0.6 × as long as article 1, with ventral horseshoe cycle of 12 setae; primary flagellum 13-articulate, almost as long as peduncle, lacking large aesthetascs; accessory flagellum 10-articulate. Antennae 2 peduncle article 4 main setal formula = 4-5-2, dorsal margin with notch with 2 robust setae and 1 slender setae, ventral margin with 6 groups of 1–4 long to medium setae, 1 distoventral elongate robust seta; article 5 almost 0.8 × as long as article 4, facial robust setae formula = 3-2, ventral margin with 4 sets of 1 elongate seta each, 3 distoventral medium to short robust setae; flagellum about 1.45 × as long as articles 4–5 of peduncle combined, 14-articulate.

Mouthparts: Mandibles with small palpar hump; right incisor with 4 teeth; left incisor with 4 weak humps in 2 branches; right lacinia mobilis bifid, distal branch flabellate, shorter than proximal, proximal branch simple, pointed; left lacinia mobilis with 4 teeth; right accessory setal row with 8 multicuspidate stout setae; molar bulbous, weak, with 3 small amalgamated robust setae and disjunct flabellate robust setae, each molar with patch of fine setae; palp article 1 short, article 2 with 1 elongate inner seta and 3 other short inner setae, article 3 about as long as article 2, oblique apex with 10 elongate slender setae. Maxilla 1 inner plate medium, with 2 elongate apical or mediofacial pappose setae, 2 apicolateral much shorter simple setae; palp article 2 with 1 medial marginal seta, and 2 apical robust setae and 7 other robust and slender setae (2 broken off in figure). Maxilla 2 plates extending equally, of equal breadth, outer with 5 apicolateral setae, inner with 1 medial seta. Maxilliped inner plate with 2 large thick apical robust setae, 3 apicofacial setae, 5 medial setae; outer plate with 11 medial and apical robust setae, 4 apicolateral setae; some setae set into cuspidate recesses; palp article 1 with 1 apicolateral seta, medial margin of article 2 moderately setose, article 3 scarcely produced, with 8 facial setae, 4 lateral setae, nail of article 4 medium, with 1 accessory setule.

Pereon: Coxa 1 slightly expanded distally, anterior margin almost straight, main ventral setae of coxae 1–4 = 11-10-8-3, posterior most seta of coxae 1–3 shortened; anterior and posterior margins of coxa 4 almost parallel, posterior margin almost vertical, almost straight, posteroventral margin not bevelled, posterodorsal corner rounded, posterodorsal margin short, concave, width to length ratio of coxa 4 = 13:16. Coxae 5–7 posteroventral setule formula = 1-4-5. Gnathopods 1–2 slightly enlarged, weakly diverse; width ratios of carpus-propodus on gnathopods 1–2 = 12:17 and 31:30, length ratios = 31:30 and 26:29; palmar humps medium, palms acute; carpus of gnathopods 1–2 elongate to medium respectively, of gnathopod 1 subovate, posterior margin of 1 flat, of 2 lobate, of gnathopod 2 triangular. Pereopods 3–4 similar, facial setae formula on merus = 3, on carpus = 5; main robust seta of carpus extending to M. 100 on propodus, carpus without posteroproximal robust setae; setal formula of propodus = 5-4 plus mid-distal robust setae, acclivity on inner margin of dactyli of pereopods 3–4 weak. Pereopods 5–6 merus-carpus narrow, facial robust setae rows poorly developed, facial ridge formula on basis of pereopods 5–7 = 0-1-1, ridge of pereopod 7 long; width ratios basis, merus, carpus, propodus of pereopod 5 = 16:10:9:4, of pereopod 6 = 27:15:9:5, of pereopod 7 = 35:7:7:3, length ratios of pereopod 5 = 27:12:15:17, of pereopod 6 = 34:32:18:24, of pereopod 7 = 41:11:10:12. Pereopod 7 basis almost reaching apex of carpus. Pereopods 5 and 7 merus without especially elongate posterodistal lobe; medial apex of propodus truncate, finely combed.

Pleon: Epimeron 1, posteroventral corner subquadrate, posterior margin almost straight, with setule, anteroventral margin with 5 short setae, posteroventral margin and corner with row of 3 elongate setae. Epimeron 2 posteroventral corner subquadrate, weakly protuberant, posterior margin almost straight, with 2 setules, facial setae in 1 row of 7, no pair set vertically. Epimeron 3 posteroventral corner rounded to quadrate, posterior margin convex, scarcely crenulate, with 2 long setae and 4 setules, ventral face with 4 small setae. Urosomite 1 with cluster of 4 midventral setae. Urosomite 3 not protuberant dorsally. Uropod 1 peduncle with 5 tiny apicolateral robust setae and very large apical robust setae, no basofacial setae, medially with 4 marginal robust setae becoming larger apically, outer ramus with 6 dorsal robust setae, inner with 3. Uropod 2 peduncle with 7 dorsal robust setae, medially with 1 medium apical robust seta, outer ramus with 5 dorsal robust setae, inner with 2. Uropods 1–2 rami with articulate enlarged apical nails, lacking accessory nail. Uropod 3 peduncle with 1 mid ventral and 1 apical robust seta, dorsally with 2–2 lateral robust setae, 1 medial robust seta; rami feminine, inner extending to M.45 on article 2 of outer ramus, apex with 1 seta, otherwise naked, article 2 with 2 elongate setae, medial margin of article 1 with 1 apical robust setae, lateral margin with 3 acclivities, setal formula = 2-2-2-2, setal formula = 0. Telson elongate, length to width ratio = 15:13, almost fully cleft, each apex broad, bevelled, acclivity absent, with ordinary lateral setule, 1 apicolateral robust seta as long as setule, basodorsal setules diverse.

MALE. Unknown.

Remarks. Protophoxus munida sp. nov. differs from Pr. australis in the presence of a large displaced robust seta on the medial apex of uropod 1 peduncle in addition to the generically important displaced robust seta on the lateral apex. The presence of this seta is also a feature of Parharpinia Stebbing, 1899 but Protophoxus further differs from Parharpinia in lacking the strong posterior setation on epimera 1–2, the lack of ventral setation on the pereopod 7 basis and the distinct nail on the maxillipedal palp. Thus, Pr. munida has a displaced robust seta on both sides of the uropod 1 peduncle and further differs from Pr. australis in the setation of epimeron 3, differing placement of facial setae and having sparse posterior setation, in the not constricted head from dorsal view; and in the absence of dorsal robust setae on the telson in adults.

The absence of dorsal robust setae on the telson of P. munida recalls species of Birubius from Australia, but that genus lacks any displaced robust setae on uropod 1 and has a non-tapered basis of pereopod 5.

Distribution. New Zealand, Otago Shelf; 132 m depth.

Figures

Figure 15. Protophoxus munidasp. nov., holotype female “q-2”,AM P39544,6.0 mm, Otago Shelf, New Zealand.Scalesrepresent 0.1 mm.

Figure 16. Protophoxus munidasp.nov., holotype female “q-2”,AMP39544, 6.0 mm, Otago Shelf, New Zealand.Scales represent 0.2 mm.