Palabriaphoxus barnardi, 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 : 575-579

Palabriaphoxus barnardi sp. nov.

urn:lsid:zoobank.org:act:74417863-E980-4A8C-87CB-021CA9F0E018

Figs 6–7

Holotype: NIWA 115630 , female “v”, 3.73 mm, eastern Tasman Sea , 42°48.5'S 169°53.5'E, anchor-box dredge, 520 m, P. K. Probert on RV Tangaroa , 20 February 1982, Cruise 1131, Station Q 694 . Paratypes: NIWA 115631 , female “w”, 3.60 mm , NIWA 115632 , female “x”, 3.44 mm, collected with holotype .

Etymology. Named in honour of the enormous contribution to phoxocephalid taxonomy made by Jerry Laurens Barnard.

Diagnosis. Eyes absent. Antenna 1 peduncular article 1 ventral apex not ensiform, peduncle article 2 shortened. Antenna 2 peduncle article 3 with 2 robust setae, article 4 shortened with facial robust setae. Right mandible lacinia mobilis multi-toothed. Maxilla 1 inner plate shorter than outer, outer plate with 9 multicuspidate robust setae. Maxilliped palp article 3 not produced. Posteroventral corner of coxae 1–3 with very small acute 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 narrow, much longer than wide. Pereopod 6 basis anterior margin setose with long robust setae, posterodistal corner produced as toothed lobe. Pereopod 7 merus, carpus, and propodus narrow; dactylus long. Urosome without basoventral setae. Epimera 1–2 without facial setae. Uropods 1–2 rami with robust setae. Uropod 1 peduncle with enlarged robust setae. Uropod 2 peduncle with mixture of robust and slender setae. Uropod 3 outer ramus article 2 with 2 long apical setae; inner ramus short, about 0.7 × the length of outer. Telson deeply cleft, apically with 1 slender plumose seta per lobe, marginally without setae on each side, without lateral robust setae.

Description. FEMALE, based on NIWA 115630, holotype, female “v”, 3.73 mm.

Head: Eyes absent; rostrum entire, weakly constricted, tapering rapidly, narrow, reaching apex of peduncle article 2 on antenna 1; posteroventral corner of head weakly produced into small tooth not curved. Antenna 1 peduncle article 1 stout, 1.5 × as long as wide, 1.6 × as long as and 2.5 × as wide as article 2, ventral margin with 3 setules and 2 plumose setae (distal corner), dorsal margin unproduced distally, with 1 distal setule; article 2 narrower than and shorter than article 1, ventral margin with 5 long plumose setae, facial margin with 2 brush setae; article 3 short, triangular, ventral margin with 1 seta, facial margin without setae; primary flagellum 4-articulate, first article elongate; accessory flagellum 2-articulate, first article elongate. Antenna 2 peduncle article 3 ventral margin with 2 simple setae; article 4 ventral margin with 13 long plumose setae and 2 short robust setae, facial margin with row of 9 robust (becoming longer distalwards) short setae, dorsal margin with tuft of 5 long plumose setae and 1 long robust seta on distal corner; article 5 0.7 × length of article 4, ventral margin with 5 plumose and 1 distal long robust seta; flagellum 5-articulate.

Mouthparts: Right mandible molar as weakly elongate plaque armed with 2 short robust setae, 1 short stubby plumose seta and 1 large-toothed robust seta, incisor blade like divided into 3 teeth, lacinia mobilis multi-toothed, accessory setal row with 6 multicuspidate stout setae, palpar hump small; palp 3-articulate, article 1 0.25 × article 2, article 2 straight, narrow, with 2 slender proximal setae and 3 distal slender setae on inner margin and no setae on outer margin, 1.1 × article 3, article 3 apex oblique with 6 long, slender setae. Maxilla 1 inner plate with 4 apical plumose setae, and small setules on medial margin; outer plate with 9 stout multicuspidate setae; palp 2-articulate, article 2 with 3 slender setae forming row medially and 4 weakly-toothed robust setae laterally and apically. Maxilla 2 inner plate slightly shorter than outer plate and slightly narrower, with 9 plumose setae; outer plate with 11 long slightly plumose setae apically stretching laterally. Maxilliped inner plate with 1 short robust seta apically and 5 long plumose setae apicofacially and medially; outer plate with 7 medial and apical blunt long robust setae, 3 apicolateral setae; palp article 1 without apicolateral setae, article 2 medial margin weakly setose, article 3 not produced, without upper facial setae, with 5 medial setae, and 5 apical setae, article 4 long subtriangular, with 1 seta laterally, 2 apical setae, apical nail elongate.

Pereon: Gnathopod 1 coxa ventral margin slightly expanded posterodistally with tiny sharp tooth on posteroventral corner, anterior margin slightly convex, ventral margin with 10 long slender plumose setae; basis undocumented; ischium small and subrectangular, posterodistal corner with 2 simple setae; merus posterior margin with 5 plumose setae; carpus 2 × as long as wide, anterior margin with 1 seta distally, posterior margin with 8 long setae; propodus 2.1 × as long as wide, 1.22 × length of carpus, anterior margin with 4 setae distally, posterior margin with 1 seta proximal to defining robust seta, 5 slender setae on facial surface; palm weakly setose and slightly convex, acute and produced to form small acute tooth at definition of palm, with 1 robust seta; dactylus reaching palmar corner, inner margin with 2 setae. Gnathopod 2 of similar size to gnathopod 1; coxa subrectangular with small acute tooth on posteroventral corner, ventral margin with 4 plumose setae, anterior margin weakly convex; basis undocumented; ischium small and subrectangular, posterior distal corner with 4 long plumose setae; merus posterior margin with 6 long slender setae; carpus short, subtriangular, 1.6 × longer than wide, anterior margin without setae, posterior margin with tuft of 11 long slender setae distally; propodus 1.7 × as long as wide, 1.3 × carpus length, anterior margin with tuft of setae distally, posterior margin weakly setose, with 1 robust seta defining palm, palm slightly convex, acute, forming small acute tooth defining palm; dactylus reaching palmar corner. Pereopod 3 coxa subrectangular, ventral margin with 5 simple setae, posteroventral corner produced to form very small acute tooth; basis 2.6 × as long as wide, posterior margin with 4 long plumose setae and distally tipped with 4 long plumose setae; ischium small and subrectangular, posterior margin with 8 distal plumose setae; merus weakly inflated, anterodistal corner bearing 2 setae, posterior margin setose with 24 medium to long plumose setae, and 5 facial setae; carpus posterior margin setose with 10 slender to robust setae, with 4 facial plumose setae; propodus posterior margin without setae, facial surface with 5 robust setae; dactylus 0.6 × length of propodus. Pereopod 4 coxa expanded posteriorly to form broadly rounded lobe, ventral margin with 5 long plumose setae and 2 very small simple setae; distal articles similar to pereopod 3. Pereopod 5 coxa bilobate, expanded posteroventrally, posteroventral lobe with 2 plumose setae; basis narrow and straight sided with slight expansion proximally, 3.25 × as long as wide, anterior margin with 1 long seta marginally and 2 plumose setae distally, posterior margin without setae; ischium small and subrectangular, anterior margin with 3 long plumose setae distally; merus anterior margin setose, with 15 long slender plumose setae marginally and 10 distally, posterior margin with 3 long plumose setae marginally and 2 long plumose setae distally; carpus anterior margin moderately setose, with 12 long plumose setae marginally and 6 long plumose setae distally, posterior margin with 6 plumose setae marginally and with 3 setae distally; propodus anterior margin with 12 long plumose setae marginally and 6 long plumose setae distally, posterior margin with 5 long plumose setae marginally and 2 distally, no facial setae present; dactylus 0.35 × as long as propodus. Pereopod 6 much longer than all other pereopods; coxa weakly expanded posteroventrally, posterior margin with 2 long plumose setae and not covered with setules; basis about 1.3 × as long as wide, anterior margin convex, bearing 3 slender setae marginally, posterior margin straight without fringe of setae, 1 small slender seta, not expanded proximally; ischium small and subrectangular without setae; merus: carpus: propodus length ratio 1:1.2:0.8; merus 1.4 × longer than wide, anterior margin with 2 small robust setae, posterior margin with 2 tufts of large slender setae composed of 2 setae each, distally with 2 slender simple setae, no setae on facial surface; carpus 1.1 × longer than wide anterior margin lined with 3 rows of long robust setae each row/tuft consisting of 3 setae, 2 robust setae distally, posterior margin distal corner with 5 long robust setae; propodus 2.0 × longer than wide, similar in length to carpus, anterior margin with 3 rows of long slender setae each composed of 3 setae, and 1 long slender seta distally, posterior margin with 6 setae distally; dactylus elongate, 1.75 × the length of propodus. Pereopod 7 coxa small and subtrapezoidal, slightly expanded posteriorly, posterior margin with 1 short seta; basis 1.2 × longer than wide (including the posteroventral lobe), strongly expanded posteroventrally to form strongly-toothed posteroventral lobe reaching beyond propodus, anterior margin bearing 8 small slender setae marginally and 6 long plumose setae distally, posterior margin strongly serrate with curved teeth, with small slender seta between teeth, 5 in total, no setae on facial surface; ischium subrectangular, 1.1 × as long as wide, anterior margin with 11 long slender plumose setae marginally; merus shorter than ischium (0.8 ×), anterior margin with 1 slender seta and 1 distally, posterior margin with 1 slender seta distally; carpus short 0.7 × merus length, anterior margin with 1 distal slender simple seta, posterior margin with 3 slender simple setae distally; propodus narrow and 1.5 × carpus, anterior margin with 2 slender setae marginally and 1 distally, posterior margin with 2 slender setae distally; dactylus elongate, 1.2 × longer than propodus.

Pleon: Epimeron 1 anteroventral corner with 2 small slender setae and fringe of setules, ventral margin with 1 small slender seta, posterior margin convex, posteroventral corner without setae, posterior margin with 1 small seta. Epimeron 2 anteroventral corner rounded with fringe of small setules, ventral margin with 5 long slender plumose setae, posteroventral corner slightly rounded, posterior margin weakly convex with 2 small slender setae, facial surface without setae. Epimeron 3 anteroventral corner rounded, ventral margin weakly concave with 2 small, slender, simple setae, posteroventral corner produced to form long acute, curved projection, posterior margin with 2 small slender setae, plate facial surface without setae. Uropod 1 peduncle 1.7 × as long as wide, dorsomedial margin with 2 long slender simple setae, dorsolateral distal corner with 1 large robust seta; outer ramus dorsal margin with 7 long slender simple setae along margin and 2 slender simple setae sub-apically; inner ramus slightly shorter than outer, dorsal margin with 4 long slender simple setae marginally and 3 slender simple setae sub-apically. Uropod 2 peduncle 1.6 × longer than wide, dorsomedial margin with 1 slender, simple seta distally, dorsolateral margin with 2 long robust setae proximally then 3 long slender simple setae marginally and then 1 large robust seta apically; outer ramus dorsal margin with 7 long slender simple setae marginally and 2 sub-apically; inner ramus shorter than outer, margins without setae and with 1 long slender seta sub-apically. Uropod 3 peduncle 1.4 × as long as wide, with 3 long slender plumose setae ventrodistally and 1 robust seta dorsodistally; outer ramus 2-articulate, article 1 ventrolateral margin with 11 long setae and 3 long setae apically, dorsolateral margin with 3 long slender setae marginally and 1 long seta apically; article 2 tiny 0.06 × length of article 1, wider than long, tipped with 3 long plumose slender setae apically; inner ramus shorter than outer ramus (0.7 ×), outer margin lined with 3 long slender plumose setae and 3 long slender setae apically. Telson short, 87% cleft, each lobe narrow and weakly rounded apically, each lobe with 2 mid-facial short plumose setae and 1 long slender apical seta and fine setules covering apices. Urosomite 3 without plumose setae on either side of telson insertion.

MALE. Unknown.

Remarks. Palabriaphoxus barnardi sp. nov. is currently known from the type locality and from very few specimens. This situation will change once further examination of the collections identified as P. palabria from around New Zealand can be undertaken. Palabriaphoxus barnardi is the closest in morphology to P. palabria but differs chiefly in the shorter length of antenna 1 article 2 and antenna 2 article 4 (elongated in P. palabria ), the absence of a serrated extended corner on the proximal posterior corner of the P6 basis, the absence of lateral robust setae on the telson and the absence of basoventral setae on the urosome (both present on P. palabria ).

Distribution. Eastern Tasman Sea; 520 m.

Figures

Figure 6. Palabriaphoxus barnardisp. nov., holotype, female “v”, NIWA 115630, 3.73 mm; paratype, female “w”, NIWA 115631, eastern Tasman Sea. Scales for MX1 and MX2 represent 0.05 mm. Scales represent 0.1 mm.

Figure 7. Palabriaphoxus barnardi sp. nov., holotype female “v”, NIWA 115630, 3.73 mm, eastern Tasman Sea. Scales for PL1 represent 0.02 mm. Other scales represent 0.1 mm.