Pariphinotus joeli Guedes-Silva, Souza-Filho and Tavares, 2024

Guedes-Silva, Elkênita, Souza-Filho, Jesser F. & Tavares, Marcos, 2024, Three new species of Amphipoda (Crustacea: Peracarida) from the remote oceanic island of Trindade, off the coast of south-eastern Brazil, Journal of Natural History 58 (45 - 48), pp. 2075-2098 : 2082-2087

Pariphinotus joeli Guedes-Silva, Souza-Filho and Tavares sp. n.

( Figures 6–9 )

Type material

Holotype 1 male (1.2 mm), MZUSP 45088 , PROTRINDADE, Trindade Island , off Espírito Santo, Brazil, Praia do M (Enseada da Cachoeira) , diurnal scuba diving, 15 m depth, 20.515° S, 29.339°W, JB Mendonça col., 08 July 2013 . Paratype: 1 male, MZUSP 45086 , ibidem, Orelhas , diurnal scuba diving, 14.4 m depth, 20.495°S, 29.342°W, JB Mendonça col., 13 November 2014 .

Diagnosis

Rostrum as long as wide, apically truncate. Antenna 1 peduncle: article 1–2 lobes shorter than articular bodies, subtriangular; article 1 apically round, and article 2 apically subacute. Gnathopod 1 carpus 1.5× longer than wide. Gnathopods 1–2 and pereopods 3–7 propodi with a subdistal robust seta. Pereopods 5–6 basis, posterior margin rounded, almost smooth and posteroventral lobe absent. Pereopod 7 basis subrectangular. Pleopod 3 inner ramus 1-articulate and reaching halfway of outer ramus article 1. Uropod 1 inner ramus 1/2 of outer ramus length; rami subapical robust setae present. Uropod 2 rami with row of tubercles and subapical robust setae.

Description

Body dorsoventrally depressed, dorsal keels present from pereonite 1 to pleonite 1. Head longer than pereonite 1 (1.3×), rostrum well developed, almost quadrate. Antenna 1 peduncle article 1 as long as wide, medial lobe shorter than articular body, subtriangular, apically round, with four marginal plumose setae; article 2 about 1.2× wider than long, medial lobe subtriangular, slender, apically subacute, with two subapical plumose setae; article 3 article as long as wide; flagellum 5-articulate, with very long aesthestascs; accessory flagellum absent. Antenna 2 slender, peduncle, article 3 shorter than article 4 (0.7×); article 4 shorter than article 5 (0.8×); flagellum 2-articulate, article 1 elongate, subequal to peduncular article 2. Mandible and maxillae as for the genus. Maxilliped inner plate subrectangular, bearing three apical stout setae; outer plate distally round, reaching half of palp article 2, medially with sparse setae; palp slender, 4-articulate, articles 1–3 subequal in length, article 4, bearing apical nail.

Pereon

Gnathopod 1 simple, coxa anterior margin concave, anteroventral corner produced, rounded, ventral margin with submarginal small setae; basis 2.1× longer than wide, anterior margin with one medial slender seta; ischium subrectangular, about 2.1× longer than wide, naked; merus subtriangular; carpus about 1.5× longer than wide, distally enlarged, anterodistal corner slightly produced, bearing three pectinate and robust setae, posterior margin with four slender and simple setae; propodus subrectangular, 1.4× longer than carpus, inner face with six robust, serrate setae, posterodistal angle with one long, robust seta; dactylus robust, curved, apical nail present. Gnathopod 2 simple, coxa subrectangular, ventral margin with submarginal small setae, posterior margin slightly concave; basis 2.1× longer than wide, anterior margin with one medial small slender seta; ischium subrectangular, about 2× longer than wide; merus subtriangular; carpus about 1.2× longer than wide; propodus subrectangular, about 2.2× longer than wide, posterodistal angle with one long, robust seta; dactylus robust, apical nail present. Pereopods 3–4 similar in shape, coxa subrectangular; basis slender, almost as long as ischium and merus together; propodus subequal in length to basis; dactylus robust, apical nail present. Pereopod 5 coxa bilobate, anteroventral lobe broadly rounded, posteroventral lobe reduced; basis as long as wide, posterior margin expanded, 2/3 produced into broadly rounded lobe, posteroventral angle not produced; ischium subrectangular; merus posterior margin lobate; carpus short,posterodistal corner weakly expanded; propodus 2.7× longer than wide; dactylus stout, apical nail present. Pereopod 6 coxa subrectangular; basis 2.7× longer than wide, posterior margin not expanded; ischium subrectangular, posterodistal angle weakly lobate; merus posterior margin lobate; carpus short, posterodistal corner weakly expanded; propodus 2.5× longer than wide; dactylus stout, apical nail present. Pereopod 7 coxa weakly bilobate; basis 1.8× longer than wide, posterior margin expanded, 2/3 produced into a broadly rounded lobe, posteroventral angle not produced; ischium subrectangular, posterodistal angle weakly lobate; merus posterior margin lobate; carpus short, posterodistal corner weakly expanded; propodus 2.2× longer than wide; dactylus stout, apical nail present.

Pleon

Pleopod 3 peduncle subtriangular, medial apex bearing two short hook setae; rami well developed; inner ramus suboval, 1-articulate, inner margin minutely setose, inner and distal margins with long slender plumose setae; outer ramus 5-articulate, article 1 longest, 67% of entire ramus length, tapering distally, inner margin minutely setose, outer and half of inner margins with long slender plumose setae. Uropod 1 peduncle with one proximal slender seta; rami, margins minutely serrate, subapical nail present; inner ramus subapical nail present. Uropod 2 peduncle distal margin with a row of tubercles, outer margin with two lateral slender setae; outer ramus about 0.8× peduncle length, inner and outer margins with a row of tubercles, margin with two slender setae; inner ramus with a row of slender setae on inner margin. Uropod 3 lanceolate, margins minutely setose, apically with one slender seta. Telson entire, round, almost as long as wide, lateral margins minutely setose.

Female

Unknown.

Etymology

This species is named after our dear colleague and friend, marine biologist Joel Braga de Mendonça Jr, in appreciation for his efforts to collect crustacean material in the Trindade and Martin Vaz archipelago.

Type locality

Enseada da Cachoeira , 20.515°S, 29.339°W, 15 m, Trindade Island, off Espírito Santo, Brazil.

Remarks

Pariphinotus currently encompasses eight species, from which the new species P. joeli sp. n. differs by a combination of characters (characters for the previously known species within brackets). It can be separated from P. amadoi Senna, Guedes, Andrade and Pereira – Filho, 2021, recently described from the oceanic island of Fernando de Noronha Island (off the north-eastern Brazilian coast), by having the inner plate of the maxilliped with three robust setae (vs four robust setae), the coxae 3 and 4 shorter than the basis (vs coxae 3 and 4 are longer than basis), uropod 1 with the inner margin of the outer ramus provided with a row of tubercles (vs row of tubercles lacking), the inner ramus of the pleopod 3 reaching halfway of the outer ramus of article 1 (vs subequal in length to the outer ramus of article 1) and the uropod 3 setose (vs uropod 3 naked).

It can be distinguished from P. escabrosus ( Barnard JL 1962) , from southern California, as follows: rami of uropods 1 and 2 with apical robust setae (vs naked rami); posterior margin of the basis of pereopods 5 and 6 not dentate (vs dentate), propodus of pereopods 6 and 7 provided with one subdistal robust seta (vs provided with two setae), and inner ramus of uropod 1 reaching halfway of the outer ramus (vs inner ramus reaching to 2/3 of the outer ramus).

The new species differs from P. galapagoanus ( Barnard JL 1979) , from Isla Santa Cruz (Galapagos Islands) in that the inner face of the propodus of the gnathopod 1 bears six serrate robust setae, (vs eight serrate robust setae); the inner margin of inner ramus of uropod 2 is provided with a row of slender setae (vs devoid of setae); and the inner ramus of the pleopod 3 is 1-articulate (vs 2-articulate).

Pariphinotus joeli sp. n. and P. seclusus ( Shoemaker, 1933) from the Tortugas can be separated from each other by the inner plate of the maxilliped reaching halfway of the length of the palp of article 2 (vs inner plate overreaching that length), the coxae 1–4 shorter than basis of gnathopods and pereopods (vs coxae longer than basis) and the basis of pereopod 6 subovate (vs basis rectangular).

Additionally, P. joeli sp. n. can be readily separated from P. seticoxa ( Ortiz, 1976) and P. tuckeri Kunkel, 1910 , from Cuba and Bermuda, respectively, in having the carpus of the gnathopod 1 1.5× longer than wide (vs carpus as long as wide and 1.7× as long as wide, respectively), and the posteroventral corner of the basis of pereopods 5 not developed (vs basis strongly developed in both species).

Figures

Figure 6. Pariphinotus sp. n. Habitus, hototype male (1.2 mm), Trindade Island, off Espírito Santo, Brazil, 15 m depth, 20.515°S, 29.339°W, MZUSP 45088. Abbreviations: Hb, Habitus. Scale Bars 0.5 mm.

Figure 7. Pariphinotus sp. n. Gnathopods, antennae and maxilliped, hototype male (1.2 mm), Trindade Island, off Espírito Santo, Brazil, 15 m depth, 20.515° S, 29.339°W, MZUSP 45088. Abbreviations: A, antenna; Mxp, maxilliped; Gn, gnathopod. Scale bars = 0.1 mm.

Figure 8. Pariphinotus sp. n. Pereopods, hototype male (1.2 mm), Trindade Island, off Espírito Santo, Brazil, 15 m depth, 20.515°S, 29.339°W, MZUSP 45088. Abbreviations: P, pereopod. Scale bars 0.1 mm.

Figure 9. Pariphinotus sp. n. Telson, uropods and pleopod, hototype male (1.2 mm), Trindade Island, off Espírito Santo, Brazil, 15 m depth, 20.515°S, 29.339°W, MZUSP 45088.Abbreviations: Pl, pleopod; T, telson; Ur, uropod. Scale bars 0.1 mm.