Metharpinia iado Alonso de Pina, 2003

Andrade, Luiz F. & Senna, André R., 2020, New and additional records of Metharpinia Schellenberg, 1931 and Microphoxus Barnard, 1960 (Crustacea: Amphipoda: Phoxocephalidae) from Brazilian waters, Papéis Avulsos de Zoologia 60, pp. 1-37 : 15-22

Metharpinia iado Alonso de Pina, 2003 ( Figs. 12‑17 )

Metharpinia iado Alonso de Pina,2003a:1031 ,figs.1‑9, 16. López‑Gappa et al., 2006:16, 52.De Broyer et al., 2007: 189. Alonso de Pina et al., 2008: 17‑19, 33. Alonso & Chiesa, 2014: 206, 207, 209, fig. 3Q‑T. Andrade et al.,

2015: 39. Material examined: 1 ♀, dissected and drawn, MBT 129,

29°13′S, 49°25′W, 27 m depth, Santa Catarina state, 25 June 1970 ( UERJ 423 ) ; 1 ♂, dissected and drawn, MBT 129, 29°13′S, 49°25′W, 27 m depth, Santa Catarina state, 25 June 1970 ( UERJ 424 ) ; 24 ♀♀, in 70% ethanol, MBT 129, 29°13′S, 49°25′W, 27 m depth, Santa Catarina state, 25 June 1970 ( UERJ 425 ) ; 24 ♀♀, in 70% ethanol, MBT 129, 29°13′S, 49°25′W, 27 m depth, Santa Catarina state, 25 June 1970 ( MZUSP 41107 ) .

Diagnosis: Head, eyes rounded and medium‑sized; rostrum constricted,narrow, elongate,spatulate.Antenna 1, peduncle article 2 elongate. Antenna 2, peduncle article 4, with 4 rows of stout setae. Mandible molar, as a small hump with stout setae, lacinia mobilis flabellate (left) or simple (right); palp, article 3 longer than article 2. Maxilliped, inner plate with 1 stout seta apically; palp, article 4 narrow, with medium apical nail, partially embedded. Gnathopods 1‑2, anterior margin weakly setose; palm acute, palmar hump small. Pereopod 7, basis, expanded posteroventrally, reaching apex of carpus. Epimeral plate 3, posteroventral corner rounded, posteri‑ or margin weakly crenulate. Urosomite 1, ventral margin with a proximal tuft of setae. Urosomite 3, not produced dorsally into a hook. Uropods 1‑2, outer ramus, with row of stout setae continuously to apex. Uropod 3, outer ramus, article 2, elongate, with 2 apical setae; inner ramus with plumose setae. Telson long, deeply cleft, apex obliquely truncate with inner corner produced into a tooth, with stout and plumose setae, dorsolateral margin with long setae.

Description: Based on female (UERJ 423). Habitus as in Fig. 12A . Head ( Fig. 13A, B ), eyes rounded and medium‑sized; rostrum, constricted, narrow, elongate and spatulate. Antenna 1 ( Fig. 13C ), peduncle article 1, about 1.4× longer than wide,ventral margin with 3 plumose setae, dorsal apex with 1 long seta; article 2, ventral margin with row of long plumose setae medially; article 3, short, ventral margin with 2 plumose setae; primary flagellum 11‑articulate; accessory flagellum 9‑articulate. Antenna 2 ( Fig. 13D ), peduncle article 4, facial stout setae formula: 1‑3‑6‑5, ventral margin with short to long plumose setae, dorsal margin with 1 stout and long plumose setae medially and distally; article 5, ventral margin with short to long plumose setae, dorsal margin weakly setose, facial margin with 5 stout setae; flagellum 14‑articulate. Left mandible ( Fig. 13H ), molar as a small hump with 5 stout setae, incisor with 3 teeth, lacinia mobilis flabellate, with 5 teeth, accessory setal row with 12 stout setae, palpar hump small; palp 3‑articulate, article 1 short, article 2, with 5 medium to long setae, article 3 slightly longer than article 2, apex oblique, with 11 medium to long setae. Right mandible ( Fig. 13I ), molar as a small hump with 5 stout setae, incisor with 3 teeth, lacinia mobilis simple, accessory setal row with 11 stout setae, palpar hump small; palp 3‑articulate, article 1 short, article 2, with 5 medium to long setae, article 3 slightly longer than article 2, apex oblique, with 13 medium to long setae. Maxilla 1 ( Fig. 13E ), inner plate with 2 plumose and 2 simple setae; outer plate with 11 multicuspidate stout setae; palp 2‑articulate, article 2, with 5 simple and 7 plumose setae. Maxilla 2 ( Fig. 13F ), inner plate, slightly shorter than outer, medial margin with row of setules and 3 plumose setae,apical and subapical margins with 6 setae; outer plate,lateral margin covered with setules, apical and subapical margins setose. Maxilliped ( Fig. 13G ), inner plate with 1 stout seta apically and 11 plumose setae; outer plate with 7 pectinate stout setae; palp, article 1 with 4 apicolateral setae, article 2, lateral margin with 7 setae, medial margin moderately setose, article 3, margins moderately setose, article 4, narrow, with medium apical nail, partially embedded.

Gnathopod 1 ( Fig. 14A ), coxa, subrectangular, ventral margin almost straight, with 20 setae; basis, anterior margin with short to long setae, posterodistal corner with 3 setae; ischium, small and subrectangular, posterodistal corner with 3 setae; merus, posterior margin with 6 setae; carpus, anterior margin with 1 short seta distally, posterior margin moderately setose; propodus, weakly setose, anterior margin with a tuft of setae, posterior margin with 1 stout seta defining palm; palm acute, with setules, palmar hump small; dactylus reaching the palmar corner. Gnathopod 2 ( Fig. 14B ), coxa, subrectangular, ventral margin almost straight, with 18 setae; basis, anterior and posterior margins with 4 setae; ischium, small and subrectangular, posterior margin with 3 setae; merus, posterior margin with 4 setae; carpus, posterior margin moderately setose; propodus, weakly setose, anterior margin with a tuft of setae, posterior margin with 1 stout seta defining palm; palm acute, with setules, palmar hump small; dactylus slightly longer than palm. Pereopod 3 ( Fig. 14C ), coxa, subrectangular, ventral margin with 13 setae; basis, posterior margin with 5 setae; ischium, small and subrectangular, posterior margin with 4 setae; merus, anterior margin with 1 seta distally, posterior margin moderately setose, facial margin with row of 5 setae distally; carpus, posterior margin moderately setose, with 1 subdistal thicker stout seta, extending 70% of propodus, facial margin with row of long setae; propodus, anterior margin with 7 stout setae, posterior margin with 6 stout setae; dactylus, about 30% the length of propodus, inner margin with an acute tooth distally. Pereopod 4 ( Fig. 14D ), coxa elliptico‑rectangular, posterodorsal margin weakly excavate, posteroventral margin with 13 setae; remaining articles are very similar to pereopod 3, differing only by some arrangements of setae. Pereopod 5 ( Fig. 15A ), coxa bilobate, posterior margin with 15 plumose setae; basis, anterior margin with short to long pectinate setae, anterodistal corner with row of pectinate setae extending to facial margin; ischium, small and subrect‑ angular, anterior margin with 5 setae; merus more robust than in M. dentiurosoma , anterior margin with long pectinate setae, posterior margin moderately setose, facial margin with dense rows of stout setae; carpus more robust than in M. dentiurosoma , anterior and posterior margins with long pectinate setae, facial stout setae formula: 4‑7‑7‑7‑12; propodus, anterior and posterior margins moderately setose; dactylus, about 55% the length of propodus, inner margin with an acute tooth distally. Pereopod 6 ( Fig. 15B ), coxa, posteroventral margin with 18 setae; basis, anterior margin with medium to long pectinate setae; ischium, small and subrectangular, anterior margin with 4 setae; merus, anterior margin with stout and long setae, posterior margin with long plumose setae, facial stout setae formula: 3‑8‑8; carpus, anterior and posterior margins weakly setose, facial stout setae formula: 4‑6‑6‑3; propodus, anteri‑ or and posterior margins weakly setose, facial margin with many sets of stout setae; dactylus, about 30% the length of propodus, inner margin with an acute tooth distally. Pereopod 7 ( Fig. 15C ), coxa, ovatorectangular, posteroventral margin wit 11 setae; basis, about 1.4× longer than wide, strongly expanded posteroventrally, reaching apex of carpus, posterior margin weakly serrate, anterodistal corner with 2 setae; ischium, subrectangular, anterodistal corner with 1 stout seta; merus, an‑ terior margin with 3 stout and 2 simple setae, posterior margin with 2 setae; carpus, anterior margin with stout setae, posterodistal corner with 3 long plumose setae; propodus, anterior and posterior margins weakly setose; dactylus, about 55% the length of propodus.

Epimeral plate 1 ( Fig. 16A ), anterior margin with 3 setae, anteroventral corner subquadrate, ventral margin with 4 long plumose setae, posterior margin straight, crenulate to weakly serrate,with 4 pectinate setae. Epimeral plate 2 ( Fig. 16B ), anteroventral corner subquadrate, ventral margin with 8 long plumose setae, posterior margin straight, weakly crenulate,with 6pectinate setae. Epimeral plate3 ( Fig. 16C ), anteroventral corner subquadrate, ventral margin with 7 setae, posteroventral corner rounded, posteri‑ or margin convex, crenulate, with 11 setae. Urosomite 1, ventral margin with a tuft of setae. Uropod 1 ( Fig. 16D ), peduncle,about 2.3× longer than wide, dorsomedial margin with 4 stout setae, dorsolateral margin with 1 stout seta apically; outer ramus, slightly longer than inner, dorsal margin with 8 stout setae, bearing 1 subapical nail; inner ramus, dorsal margin with 3 stout setae, bearing 1 subapical nail. Uropod 2 ( Fig. 16E ), peduncle, about 2.2× longer than wide, dorsomedial margin with 7 stout setae, ventrolateral margin with 1 stout seta apically; outer ramus, slightly longer than inner, dorsal margin with 6 stout setae, bearing 1 subapical nail; inner ramus, dorsal margin with 3 stout setae, bearing 1 subapical nail. Uropod 3 ( Fig. 16F ), peduncle, about 1.5× longer than wide, ventral margin with 5 stout setae,dorsal margin with 1 simple and 1 stout seta; outer ramus, 1.3× longer than inner, article 1, dorsal margin with 5 plumose setae, ventral margin with 3 acclivities, stout setae formula: 3‑3‑3‑3, article 2, elongate, with 2 plumose setae apically; inner ramus, margins with long stout setae. Telson ( Fig. 16G ), about 75% cleft, apex obliquely truncate with inner corner produced into a tooth, with 1 plumose and 5 stout setae on each lobe, dorsolateral margin with 7 long setae on each side.

Sexual dimorphism: Based on male (UERJ 424). Body ( Fig. 12B ), smaller in size. Head ( Fig. 17A, B ), eyes, larg‑ er and more pigmented; rostrum, constricted, narrow, elongate and spatulate. Antenna 1 ( Fig. 17C ), peduncle article 1, about 1.4× longer than wide, ventral margin with 1 plumose seta, dorsal margin with 2 setae distally; article 2, ventral margin with short to long pectinate setae; article 3, short; primary flagellum 10‑articulate, with calceoli on articles 1‑3; accessory flagellum 9‑articulate. Antenna 2 ( Fig. 17D ), peduncle article 3, dorsal margin covered with setules; article 4, ventral margin with short to long setae, dorsal margin with 1 stout and 4 long se‑ tae,covered with setules,facial stout setae formula:3‑6‑6; article 5, ventral margin with short to long setae, dorsal margin with 3 tufts of setae and 1 calceolus distally, facial margin with 4 stout setae; flagellum 36‑articulate, with calceoli on articles 2‑4.

Gnathopods 1‑2 ( Fig. 17E, F ), similar in size, but more robust than in female.

Uropod 3 ( Fig. 17G ), peduncle, 1.9× longer than wide, with 6 stout setae distally, dorsal margin with 3 setae; outer ramus, article 1, ventral margin with two acclivities, stout setae formula: 3‑3‑2, dorsal margin covered with long plumose setae, article 2, with 2 medium plumose setae apically; inner ramus, slightly shorter than outer, margins covered with long plumose setae.

Type locality: Argentine Sea, El Rincón, Buenos Aires, Argentina (39°49′49″S, 61°50′30″W).

Remarks: Metharpinia iado was described with material from Buenos Aires ( Argentina) and this is the first record of the species for Brazilian waters. According to Alonso de Pina (2003a), this is species is similar to M. longirostris . However, it can be distinguished by M. longirostris by the following states of characters ( M. longirostris characters in parenthesis): antenna 2, peduncle article 4, stout setae formula: 1‑3‑6‑5 (1‑3‑8‑4); gnathopods 1‑2, palm acute (almost transverse); pereopod 7, basis posteroventrally expanded, reaching apex of carpus (reaching apex of merus); epimeral plate 3, posterior margin strongly convex (weakly convex); telson, with 4 stout setae on each lobe (2‑3 stout setae).

Geographic distribution: Argentina: Argentine Sea; Brazil: coast of the Santa Catarina state.

Bathymetric range: 9‑27 m depth.

Figures

Figure 12.Metharpinia iado Alonsode Pina,2003: (A) Habitus of female(UERJ 423);(B) Habitus of male (UERJ 424).Scale bars:2.0 mm.

Figure 13. Metharpinia iado Alonso de Pina, 2003, female (UERJ 423): (A) Head in lateral view; (B) Head in dorsal view; (C) Right antenna 1; (D) Right antenna 2; (E)Left maxilla 1; (F) Left maxilla 2;(G) Left maxilliped;(H) Left mandible;(I) Right mandible.Scale bars:0.5 mm forA-D;0.1 mm for E-F;0.2 mm forthe remaining.

Figure 14. Metharpinia iado Alonso de Pina,2003, female (UERJ 423): (A) Right gnathopod 1; (B) Right gnathopod 2; (C) Right pereopod 3; (D) Right pereopod 4. Scale bars:0.5mm.

Figure 15. Metharpiniaiado Alonso de Pina,2003,female (UERJ 423): (A) Right pereopod 5;(B) Right pereopod 6; (C) Right pereopod 7. Scale bars:0.5 mm.

Figure 16. Metharpinia iado Alonso de Pina,2003,female (UERJ 423): (A) Right epimeral plate 1; (B) Right epimeral plate 2; (C) Right epimeral plate 3; (D) Right uropod 1; (E) Right uropod 2; (F) Right uropod 3; (G) Telson.Scale bars:0.5 mm for A-C;0.2 mm for the remaining.

Figure 17. Metharpinia iado Alonso de Pina, 2003, male (UERJ 424): (A) Head in lateral view; (B) Head in dorsal view; (C) Right antenna 1; (D) Right antenna 2; (E)Right gnathopod 1; (F) Right gnathopod 2; (G) Right uropod 3.Scale bars:0.5 mm for A-F;0.2 mm for G.