Amphipoda Latreille, 1816

Senna, André R., Guedes, Urssula N., Andrade, Luiz F. & Pereira-Filho, Guilherme H., 2021, Lamprochernes nodosus, Zoological Studies (Zool. Stud.) 60 (57), pp. 1-12 : 2-8

Order Amphipoda Latreille, 1816 Suborder Senticaudata Lowry and Myers, 2013 Family Phliantidae Stebbing, 1899 Genus Pariphinotus Kunkel, 1910

Diagnosis: See Lazo-Wasem et al. (1989: 4).

Composition of the genus: The genus Pariphinotus comprises seven species: P. amadoi sp. nov.; P. escabrosus ( Barnard, 1962) ; P. galapagoanus ( Barnard, 1979) ; P. lepas ( Hirayama, 1987) ; P. seclusus ( Shoemaker, 1933) ; P. seticoxa ( Ortiz, 1976) ; and P. tuckeri Kunkel, 1910 .

Type-species: Pariphinotus tuckeri Kunkel, 1910 .

Pariphinotus amadoi sp. nov. ( Figs. 1–4 ) urn:lsid:zoobank.org:act:335599A6-A193-4611-8EE7-275CD2D14BEE

Material examined: Holotype: male, 2.5 mm, dissected and drawn, from rhodolith beds, Ressureta Chanel , between Meio and Rata Islands, Fernando de Noronha Archipelago, Pernambuco state, Brazil, 3°49'2.51"S, 32°23'34.10"W, 12 m depth, Pereira-Filho, G.H. col., September 2012 ( UERJ 543 ) . Paratype: one female, in ethanol 70%, same sampling data (UFBA 2280).

Etymology: The epithet ‘ amadoi ’ is attributed to this species in honour of Dr. Gilberto M. Amado-Filho (in memoriam), who dedicated part of his career revealing the importance of the Southwestern Atlantic rhodolith beds. At the beginning of 2000’s, during a field trip to sample Brazilian kelps, Dr. Amado-Filho was impressed about the extension of the rhodolith beds in which those algae were attached. Thereafter, he devoted his scientific knowledge to reveal the extensiveness and high biodiversity associated with these habitats. He never forgot the importance of sharing his knowledge of rhodoliths with non-scientists and thus left us a legacy to marine biodiversity conservation.

Diagnosis: The new species can be diagnosed by combining the following characters (character in “ ” is an exclusive state within the genus): Rostrum elongate and apically truncate. Antenna 1 peduncle, lobe of first article shorter than articular body, subtriangular, apically round. Pereopods 3–7 dactylus, apically plumose seta present. Pereopod 6 basis, posterior lobe subquadrate, posteroventral lobe absent. Pereopod 7 basis, posterior lobe subrectangular, with slight distal indentation. “Pleopod 3 medial apex of peduncle with 2 small hook setae. Uropod 1 peduncle not exceeding the distal margin of telson”; rami subapical nail present, outer ramus, outer margin with 1 seta. Uropod 2 rami with row of tubercles present.

Description: Based on holotype (UERJ 543). Body dorsoventrally depressed, dorsal keels present from pereonite 1 to pleonite 1. Head small, rostrum well developed, apically truncate, dorsal margin with proximal concavity. Antenna 1 peduncle, first article about 1.2 × wider than long, medial lobe shorter than articular body, subtriangular, apically round, with three subapical slender setae, second article about as long as wide, medial lobe subtriangular, slender, apically subacute, with two subapical slender setae, third article subrectangular, slightly longer than wide; flagellum 4-articulate, first article about 1.5 × longer than wide, subrectangular, bearing group of seven slender setae medially on lateral margin and a group of four slender setae laterodistally, second article short, about 1.7 × wider than long, bearing five facial slender setae, third article about 2.4 × longer than wide, tapering distally, fourth article minute, with two apical long slender setae; accessory flagellum absent. Antenna 2 slender, peduncle, third article enlarged, about 1.6 × longer than wide, ventral margin with one distal slender seta, fourth article slender, about 3.4 × longer than wide, with two slender setae dorsodistally and three slender setae ventrally, fifth article subrectangular, about 2.6 × longer than wide, with one slender seta dorsodistally and three slender setae ventrally; flagellum 2-articulate, first article short, about twice longer than wide, with two subdistal slender setae, second article minute, with three long apical slender setae. Mandible without palp; molar as a slender projection with one apical slender seta; incisor 4-cuspidate. Maxilla 1 inner plate reduced; outer plate 1.4 × longer than wide, with five apical multi-cuspidate stout setae. Maxilla 2 stout, inner and outer plates almost completely coalescent, inner plate 1.9 × wider than outer plate, bearing three apical plumose stout setae. Maxilliped inner plate slender and subrectangular, bearing four apical stout setae; outer plate distally round, reaching half of palp second article, medial margin setose; palp slender, 4-articulate, first article about twice longer than wide, second article about 1.7 × longer than wide, medial margin bearing four pectinate setae, third article subequal in length to second article, about 1.7 × longer than wide, suboval, bearing nine pectinate setae medially, fourth article unguiform, about 2.4 × longer than wide, bearing one apical simple seta.

Pereon: Gnathopod 1 simple, coxa about 1.5 × longer than wide, anterior margin concave, anteroventral corner produced and round, ventral margin with submarginal small setae; basis 2.5 × longer than wide, anterior margin with one medial slender seta; ischium subrectangular, about 1.6 × longer than wide, naked; merus subtriangular, about 1.7 × longer than wide, posterior margin convex, bearing two distal slender setae; carpus about 1.4 × longer than wide, distally enlarged, anterodistal corner slightly produced, bearing two pectinate and one simple stout setae, posterior margin with two slender setae; propodus subrectangular, about 2.3 × longer than wide, anterior margin with one medial slender seta, bearing one pectinate stout seta and four simple slender setae distally, posterior margin with two medial slender setae, bearing one stout and four slender setae distally; dactylus robust, about 1.8 × longer than wide, curved, bearing one small anterodistal slender seta, apical nail present. Gnathopod 2 simple, coxa subrectangular, about 1.3 × longer than wide, anterior and ventral margins with submarginal small setae, posterior margin slightly concave; basis stout, about 2.6 × longer than wide, posterior margin with one medial small slender seta; ischium subrectangular, about 1.8 × longer than wide, posterior margin with one distal small slender seta; merus subtriangular, about 1.6 × longer than wide, posterior margin slightly convex, bearing two slender setae; carpus about 1.3 × longer than wide, slightly enlarged distally, anterodistal corner bearing one pectinate stout seta, posterodistal corner with one elongate slender seta; propodus subrectangular, about 2.8 × longer than wide, anterior margin with one proximal and three distal slender setae, posterior margin with one proximal slender seta, bearing one stout and three slender setae distally; dactylus robust, about twice longer than wide, curved, anterior margin bearing one proximal plumose seta, posterior margin with one slender seta, apical nail present, bearing one anterior subapical slender seta. Pereopod 3 coxa about 1.2 × longer than wide, anterior margin with few submarginal slender setae, posterior margin slightly concave; basis about 2.3 × longer than wide, anterior margin with one medial seta, posterior margin with one medial seta, posteroventral corner bearing one slender seta; ischium about 2.1 × longer than wide, posterior margin slightly convex, bearing two small setae; merus about 1.2 × longer than wide, anterodistally lobate, anterior margin bearing one stout seta distally; carpus about 0.8 × the length of merus, about as long as wide, anterior margin slightly produced, bearing one distal stout seta, posterior margin with two slender setae; propodus subrectangular, about 2.8 × longer than wide, anterior margin with two slender setae, anterodistal corner with three slender setae, posterior margin with 1 medial seta and a distal group of four slender setae and one pectinate stout seta; dactylus about 2.5 × longer than wide, curved, anterior margin with one distal slender seta, apical nail present. Pereopod 4 similar to pereopod 3, coxa slightly longer than wide, anterior and ventral margins with submarginal setae, posterior margin concave; basis 2.1 × longer than wide; merus and carpus, bearing one anterodistal pectinate stout seta each; propodus 2.6 × longer than wide; dactylus, anterior margin bearing one proximal apically plumose and one distal simple seta, posterior margin with one slender seta, apical nail present. Pereopod 5 coxa bilobate, about twice wider than long, anteroventral lobe broadly round, posteroventral lobe reduced, bearing one small slender seta; basis about 1.2 × wider than long, anterior margin with one slender seta, posterior margin expanded, produced into a broadly rounded lobe, bearing three slender setae; ischium about 1.6 × longer than wide, anterodistal corner with one slender seta; merus about as long as wide, posterodistally lobate, posterior margin with three slender setae; carpus about as long as wide, posterodistal corner weakly expanded; propodus stout, about 2.8 × longer than wide, anterior margin with one medial and a distal pair of slender setae, bearing one stout seta anterodistally, posterior margin with five slender setae, posterodistal corner with one slender seta; dactylus stout, about 2.5 × longer than wide, curved, bearing one anterior, one posterior, and one distal slender setae, anterior margin rough, posterior margin with one proximal apically plumose seta, apical nail present. Pereopod 6 basis about 1.3 × longer than wide, posterior margin expanded as a subquadrate proximal lobe, with strong distal indentation, posteroventral lobe absent; ischium about 1.7 × longer than wide, subrectangular, anterior margin with one medial slender seta, anterodistal corner with one slender seta; merus about 1.9 × longer than wide, posterodistally lobate, anterior margin with two slender setae, posterior margin with one slender seta; carpus about 1.5 × longer than wide, posterodistal corner weakly expanded, anterior margin with two slender setae, posterior margin with one slender seta; propodus about 3.2 × longer than wide, anterior margin with six slender setae, bearing 1 stout seta anterodistally, posterior margin with one medial and two distal slender setae; dactylus about 2.7 × longer than wide, curved, bearing one anterior and one posterior slender setae, anterior margin rough, posterior margin with one proximal apically plumose seta, apical nail present. Pereopod 7 basis about 1.7 × longer than wide, subrectangular, posterior margin weakly expanded, with slight distal indentation, bearing a small medial slender seta, posteroventral lobe absent; ischium about 1.9 × longer than wide, distally enlarged; merus about 1.4 × longer than wide, posterodistally lobate, anterior margin with two slender setae, posterior margin with one slender seta; carpus about 1.4 × longer than wide, suboval, anterior margin with two slender setae, posterior margin with one slender seta; propodus stout, about 3.3 × longer than wide, anterior margin with one medial and four distal slender setae, bearing one stout seta anterodistally, posterior margin with one medial and two distal slender setae; dactylus about twice longer than wide, curved, with two anterodistal and one laterodistal slender setae, anterior margin distally rough, posterior margin with one proximal apically plumose seta, apical nail present.

Pleon: Pleopod 3 peduncle subtriangular, medial apex bearing two small hook setae; rami well developed; inner ramus about 1.8 × longer than wide, suboval, 2-articulate, inner margin minutely setose, distally and apically with long slender plumose setae; outer ramus about 3 × longer than wide, about 2.2 × longer than inner ramus, 7-articulate, first article about half of entire ramus, tapering distally, outer margin, apex, and distal end of inner margin bearing long slender plumose setae. Uropod 1 biramous, peduncle does not exceed the apex of telson, about 2.9 × longer than wide, laterodistal corner bearing one stout seta; outer ramus about 0.7 × the length of peduncle, about 1.5 × longer than inner ramus, apically round, inner, outer, and apical margins minutely setose, subapical nail present; inner ramus, apically round, inner, outer, and apical margins minutely setose, subapical nail present. Uropod 2 biramous, peduncle stout, about 1.9 × longer than wide, three lateral stout setae; outer ramus about 0.7 × the length of peduncle, about 1.3 × longer than inner ramus, longitudinal row of tubercles present, apical nail present; inner ramus, inner margin minutely setose, longitudinal row of tubercles present, apical nail present. Uropod 3 lacking rami, about 1.7 × longer than wide, lanceolate, apically subacute, naked. Telson entire, round, slightly longer than wide, distal margin minutely setose.

Figures

Fig. 1. Pariphinotus amadoi sp. nov., Holotype, Fernando de Noronha Archipelago, Brazil (UERJ 543). (A) Habitus, lateral view; (B) Habitus, dorsal view. Scale bars = 0.5 mm.

Fig. 2. Pariphinotus amadoi sp. nov., Holotype, Fernando de Noronha Archipelago, Brazil (UERJ 543). (A–B) Maxillae 1–2; (C) Mandible; (D) Maxilliped; (E–F) Antennae 1–2. Scale bars = 0.05 mm for A–B; 0.1 mm for the remainders.

Fig. 3. Pariphinotus amadoi sp. nov., Holotype, Fernando de Noronha Archipelago, Brazil (UERJ 543). (A–B) Gnathopods 1–2; (C–D) Pereopods 3–4. Scale bars: 0.2 mm.

Fig. 4. Pariphinotus amadoi sp. nov., Holotype, Fernando de Noronha Archipelago, Brazil (UERJ 543). (A–C) Pereopods 5–7; (D) Pleopod 3; (E–F) Uropods 1–2; (G) Uropod 3 + Telson, dorsal view. Scale bars: 0.2 mm for P5–7; 0,1 mm for the remainders.