Aruga paracuru, Sorrentino & Moraes & Senna, 2019

Sorrentino, Rayane, Moraes, Elienai E. B. & Senna, André R., 2019, Four new species of Lysianassidae Dana, 1849 (Crustacea: Amphipoda) From Northeastern Brazilian coast, Zootaxa 4585 (1), pp. 1-26 : 13-19

Aruga paracuru sp. nov.

( Figs 9–13 )

Material examined. Holotype, female, ovigerous, 8.9 mm, Paracurú Beach , Ceará, (03°25'S, 39°02'W), 20 August 2012, UFBA 3224 . Paratype, female, Paracurú Beach , Ceará, (03°25'S 39°02'W), 18 October 2012 in beach rock. UERJ 74 .

Type-locality. Paracurú Beach, Ceará, Brazil.

Etymology. The specific epithet corresponds to the beach Paracurú. This name comes from the Tupi indigenous language.

Diagnosis. Upper lip, apical margin subacute, distal margin with a conical projection. Epimeral plate 3, posteroventral corner straight. Telson, lateral rounded.

Description. (Based on holotype). Head without setae. Lateral cephalic lobe subtriangular. Antenna 1, approximately same length as the antenna 2; article 1 of peduncle robust, subquadrate, three plumose setae in dorsal margin and two thin setae proximally, ventral margin with five plumose setae and distal corner with three slender setae; article 2, 0.3 × article 1 length, apical corner with slender setae and distal corner with slender and plumose setae, article 3 half the length of article 2, with three slender setae in anterior margin; primary flagellum 12-articulate, two strong fields of callynophore, almost articles of flagellum with setae in anterior margin; accessory flagellum with 7 articles. Antenna 2, peduncle 13-articulate, anterior margin of articles with simple setae.

Mouthparts forming a subquadrate bundle. Epistome and upper lip slightly separated, with one seta proximal, upper lip dominant, apical margin subacute, dorsal and ventral margins with small simple setae, apical margin with simple seta, anteroventral angle with a conical projection. Mandible, ventral margin with three robust serrate setae, incisor smooth, convex and laminar; lacinia mobilis in left mandible, modified a slender seta, with thin accessory seta; molar triangular, triturative, with small setae and scales; palp 3-articulate, article 1, about half length of article 2, article 2 with three simple setae in anterior margin, four pectinates setae in apical margin, article 3, 0.7 × article 2 length, anterior margin concave, surface setose, apex with long setae. Maxilla 1, inner plate, tapering distally, tuft of thin setae in inner margin, two setae plumose in apical margin; outer plate, with 11 setal-teeth in 5/6 arrangement: ST1 asymmetrical, left ST1 2-cuspidate, right ST1 1-cuspidate, ST2–4 2-cuspidate, ST5 3-cuspidate, ST6 5-cuspidate, ST7 asymmetrical, left ST7 3-cuspidate, right ST7 5-cuspidate; STA–D 2-cuspidate; maxillar palp with 2 articles, article 2, about 7 × longer than article 1, distal margin with slender setae and with subterminal seta. Maxilla 2, inner plate with small setae in medial margin, five plumose setae in subterminal margin, slender setae in apical margin; outer plate, some setae in subapical surface, slender setae in apical corner. Maxilliped, inner plate, subtriangular, with plumose setae in lateral margin, apical margin with three nodular setae and two simple setae; outer plate subrectangular; palp, 4-articulate, article 1, 0.5 × article 2 length, slender plumose setae in lateral margin, article 2, lateral and apical margins with simple and slender setae, article 3, subrectangular, lateral and apical margins with simple setae, dactylus with subterminal seta.

Pereonites 1–7: without setae. Gnathopod 1 simple, coxa well-developed, anterior margin convex, anteroventral corner produced, rounded, with simple setae, posteroventral corner rounded; basis, anterior margin with simple setae, posterior margin convex, posteroventral margin with tuft of setae; ischium, 0.4 × length of basis, anterior margin concave, anteroventral corner rounded, with four setae, posterior margin setose; merus, expanded posteriorly, posterior margin with small setae proximally and slender seta posterodistally; carpus, subrectangular, posteroventral corner with four setae; propodus, 2.4 × longer than dactylus, anterodistal and posterior margins with setae; dactylus, with small setae in posterior margin, with nail. Gnathopod 2, minutely subchelate, coxa, 2.2 × longer than wide, setae in ventral margin; basis, 3.5 × longer than wide, anterior margin with simple setae; ischium elongate, 4 × longer than wide, with slender seta in surface distally; merus small, 2.5 × longer than wide, anterior margin convex distally, posterior margin convex and covered by tufts of small setae, posterior corner with slender setae; carpus, 2.5 × longer than merus, anterior margin slightly convex, with small setae and anteroventral corner with slender setae, posterior margin strongly convex, covered by scales, posteroventral corner with simple and slender setae; propodus, small, rounded, covered by setae, anterior margin convex, with setae, anterior margin with irregular and long setae, posterior margin with simple setae, posteroventral corner strongly convex, with scales, palm slightly serrate; dactylus very small, posterior margin serrate, the tip touches the palm, but not exceeding it.

Pereopod 3, coxa 2.2 × longer than wide, subequal in size to coxa 2, basis 3 × longer than wide, anterior and posterior margins with setae; ischium small, anterior margin convex, posterior margin convex, with slender setae; merus elongate, 1.9 × longer than wide, expanded anteroventrally, with slender setae, posterior margin setose; carpus, one setae on anteroventral corner, posterior margin setose; propodus with setae in anterior margin and on anteroventral corner, posterior margin setose; dactylus, 0.7 × propodus length, with nail. Pereopod 4, coxa deeper than wide, with large posteroventral lobe, anteroventral corner quadrate; basis, 3.2 × as longer than wide, posteroventral setose; ischium, merus, carpus and propodus setose posteriorly, merus elongate, 1.9 × as longer than wide; carpus, 0.4 × merus length, posteroventral margin with setae; dactylus with nail. Pereopod 5, coxa large, anterior margin slightly straight, anteroventral corner convex, posterior margin rounded; basis, anterior margin convex, with small setae and tufts of simple setae, posterior margin convex, serrate, posteroventral corner rounded; ischium, anteroventral corner with setae; merus, carpus and propodus, anterior margin with sets of setae; merus, posterior margin expanded, with sets of setae (1–1–1–2); dactylus with nail. Pereopod 6, coxa concave anteriorly, posterior margin convex, ventral margin rounded; basis, convex anteroventrally, with simple setae, posterior margin slightly serrate; ischium with setae in anterior margin, merus with sets of two setae in anterior margin and three setae in posterior margin, carpus, anterior margin with sets of setae with accessory setae (2–2–1–4), posterior margin, one seta, posteroventral corner with two setae with accessory setae; propodus, anterior margin with sets of two setae with accessory seta, posteroventral corner with four setae; dactylus with one setae in surface, with nail. Pereopod 7, coxa, posteroventral margin convex, basis anterior and posterior margin convex, setae in anterior margin, posterior margin serrate, ischium, setae with accessory setae in anteroventral corner, merus, anterior margin with three sets of setae with accessory seta, posterior margin with one seta, posteroventral corner with one seta with accessory seta.

Epimeral plates 1–3: with setae in dorsal margin. Epimeral plate 3, posteroventral margin with straight angle. Urosomite 1–3, with dorsal carinas (two in lateral margins and one in medial margin). Uropod 1, peduncle 0.8 × rami length, dorsal margin with two setae with accessory seta, posterior margin with one seta with accessory seta; inner ramus with two setae with accessory setae in dorsal margin; outer ramus, 1.3 × longer than inner ramus, with three setae mediodorsally. Uropod 2, peduncle, two setae in dorsal margin; inner ramus with two setae dorsally and with constriction; outer ramus, dorsal margin with two setae, ventral margin with one seta. Uropod 3, setae with accessory setae in dorsal margin and two setae in posterior margin; inner and outer rami without setae. Telson entire, as long as wide, with scales in lateral surfaces, lateral margins rounded, strongly emarginated, with three setae in subterminal margins.

Remarks: Aruga paracuru sp. nov. differs from A. holmesi by having: upper lip with apical margin rounded, forming a slightly anterior acute angle; epistome with conical projection; second article of mandibular palp with pectinate setae, third article setose; maxilla 1, setal-teeth, ST1 asymmetrical, left ST1 2-cuspidate, right ST1 1- cuspidate, ST2-4 2-cuspidate, ST5 3-cuspidate, ST6 5-cuspidate, ST7 asymmetrical, left ST7 3-cuspidate, right ST7 5-cuspidate, ST1 STA–D 2-cuspidate; outer plate of maxilliped subrectangular, palp, article 2 geniculate; urosomite 1–3 with dorsal carina, posteroventral margin with acute angle; and telson rounded strongly emarginated.

Differently from Aruga oculata , A. paracuru has upper lip apically acute; epimeral plate 3, posteroventral margin almost forming an angle of 90°, distal margin acute; urosomites 1–3 with a dorsal carina, and telson subequal in length and width, with scales in lateral surfaces, lateral margins rounded, strongly emarginated, with three setae in subterminal margins.

Figures

FIGURE 9. Aruga paracuru sp. nov.: female, holotype, Paracurú, Ceará, 03°25'S 39°02'W; UFBA 3224. Scale bars: 10.0 mm.

FIGURE 10. Aruga paracuru sp. nov.: female, holotype, Paracurú, Ceará, 03°25'S 39°02'W; UFBA 3224. Scale bars: 1.0 mm for E; 0.5 mm for the remainder.

FIGURE 11. Aruga paracuru sp. nov.: female, holotype, Paracurú, Ceará, 03°25'S 39°02'W; UFBA 3224. Scale bars: 0.5 mm for Mp; 1.0 mm for the remainder.

FIGURE 12. Aruga paracuru sp. nov.: female, holotype, Paracurú, Ceará, 03°25'S 39°02'W; UFBA 3224. Scale bars: 1.0 mm.

FIGURE 13. Aruga paracuru sp. nov.: female, holotype, Paracurú, Ceará, 03°25'S 39°02'W; UFBA 3224. Scale bars: 1.0 mm for P6, P7 and T; and 5.0 mm for U1–U3.