Shoemakerella ungulata, 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 : 19-24

Shoemakerella ungulata sp. nov.

( Figs 14–17 )

Material examined. Holotype, female, 7.2 mm, April 2013, channel of Maraú River , Camamu Bay, Bahia, Brazil, (13°54'S 32°01'W). 6.5 mm, UFBA 3223 .

Type-locality. Camamu Bay, Bahia, Brazil.

Etymology. The epithet refers to the Latin word ungula, that means a hoof or nail, present in the gnathopod 1 dactylus.

Diagnosis. Gnathopod 1, dactylus with a strong nail, 1.4 × longer than dactylus. Gnathopod 2, propodus elongate, 4 × longer than wide and 0.9 × carpus length. Uropod 3, peduncle very elongated (1.3 × longer than outer ramus). Telson strongly emarginated.

Description. (Based on holotype). Head longer than deep; lateral cephalic lobe rounded, subacute; rostrum absent; eyes reniform. Antenna 1, peduncle, article 1 robust, dorsal margin convex, ventral margin straight, with three plumose setae; article 2 and 3 similar in length; article 2, anterior margin concave, tuft of setae on anterodorsal and anteroventral corners, article 3, slender setae in anterior margin, callynophore absent; primary flagellum 10-articulate; accessory flagellum 5-articulate, articles 1, 2 and 5, with setae in anterior margin. Antenna 2, article 1–3 subequal in length, article 3, setae in anterior and ventral margin, article 4 × longer than article 3, anterodorsal and posteroventral corners with tufts of setae, posteroventral margin with a small plumose seta, ventral margin with slender setae; article 5 small; flagellum 6-articulate; calceoli and callynophore absent.

Mouthparts forming a subquadrate bundle. Epistome and upper lip separate with a slightly notch; epistome slightly concave; upper lip rounded dorsally, anterior margin concave, distal margin with notch, forming a rounded shape, ventral margin concave, anteroventral margin setose. Mandible, incisor smooth, one small seta proximal an incisor, with two accessory setae, lacinia mobilis absent in right and left mandible; molar triturative, setose; palp 3- articulate, article 2, twice the size of the article 1, with setae in apical margin, article 3, rounded in apical margin, with two setae. Maxilla 1, inner plate with thin setae in lateral margins, without apical setae; outer plate, setal-teeth in 6/5 arrangement: ST1 1-cuspidate, ST2 and ST3 2-cuspidate, ST4 3-cuspidate, ST5 6-cuspidate, ST6 12- cuspidate and ST7 9-cuspidate (left maxilla 1, ST6 and ST7 10-cuspidate); STA conical, elongated, STB–D 1- cuspidate, small; palp 2-articulate, apical margin serrated, small subterminal seta. Maxilla 2, inner margin rounded apically, serrated setae in apical margin; outer plate, narrow, 2.6 × longer than wide, apical margin with slender setae. Maxilliped, inner plate narrow, thin setae in surface and apical margins, outer plate, inner margin straight, outer margin rounded, slightly serrated apically; palp 4-articulate, article 1 1.6 × longer than wide, article 2, elongated, 2.3 × longer than article 1, longer setae in outer margin, article 3 rounded apically, apical and outer margin with setae, dactylus with seta.

Gnathopod 1, simple, coxa large, 1.5 × wider than coxa 2, expanded anteriorly; basis large, 1.5 × longer than wide, anterior margin and posteroventral corner with simple setae; ischium small, posterior margin with setae; merus, subtriangular, posteroventral corner acute, posterior margin with small setae distally and simple setae apically; carpus subrectangular, anterior margin with three setae, anteroventral and posteroventral corners with tuft of setae, ventral margin slightly concave; propodus with setae in anterodistal and posterodistal margin; dactylus with a wide nail, almost one and a half times greater. Gnathopod 2, minutely subchelate, coxa long, 2.6 × longer than wide, basis long, 5.3 × longer than wide, anterior margin with three simple setae; ischium long, 2.6 × longer than wide, anterior and posterior margins with one simple seta, posteroventral corner with tuft of setae; merus rounded, with convex protuberance anteriorly, posterior margin with thin setae, carpus slender, rounded ventrally, ventral margin and posterior margin setose; propodus long, 4 × longer than wide and 0.9 × carpus length, anterior and posterior margin setose, posterodistal corner with scales; palm acute; dactylus small, not reach the palmar angle, with nail.

Pereopod 3, coxa long, 2.7 × longer than wide, basis 2.5 × longer than wide, anterior margin with two setae, posterior margin with one seta and posteroventral corner with a tuft of setae; ischium, posterior margin setose; merus, 1.5 × the carpus length, anteroventral angle expanded, with tuft of setae, posterior margin with simple setae; carpus small, rounded ventrally, propodus 1.3 × the carpus length; dactylus long, 0.6 × the propodus length, with nail. Pereopod 4, coxa expanded posteriorly, basis with two setae in anteroventral corner, ischium setose posteriorly, merus, anteroventral corner expanded, with tuft of setae, posterior margin setose; carpus setose posteriorly; propodus with two simple setae in anterior margin apically and seven in posterior margin. Pereopod 5, coxa rounded, 1.4 × wider than long, basis rounded, approximately as longer as wide, anterior margin setose; ischium small, about half merus length, one seta in anteroventral margin; merus, anterior margin setose, posterior margin with two tufts of two setae. Pereopod 6, coxa, anterior margin concave, posterior margin convex, with two setae; basis, anterior margin convex, with simple setae, posterior margin convex proximally and concave distally; ischium small, 0.3 × merus length, anterior margin with setae; merus, anterior margin with simple setae, posterior margin with one seta, posteroventral corner with a robust seta. Pereopod 7, coxa, anterior margin straight, posterior margin slightly convex; basis, anterior margin convex proximally, posterior margin slightly serrated; ischium small, posteroventral angle expanded ventrally; merus, anterior margin with stes of two setae, anteroventral corner with four setae, posterior margin with sets of two setae, one of than with accessory seta, posteroventral corner with three setae.

Pleonites 1–3: Epimeral plate 3, posterior margin concave until half, posterodistal margin rounded. Uropod 1 long, peduncle subequal in length to rami, dorsal inner and outer margin with setae; rami subequal in length, inner and outer rami with setae in dorsal margin. Uropod 2, 0.7 × uropod 1 length, peduncle with setae in dorsal inner margin; rami subequal in length, inner ramus with constriction with a slender seta; outer ramus with setae in dorsal margin, with nail. Uropod 3, peduncle long, 2.75 × longer than wide and 1.3 × longer than outer ramus, dorsolateral flange strongly developed, dorsal margin with 5 setae, posteroventral corner with one seta; inner ramus, 0.8 × shorter than outer ramus, dorsal margin with two setae, outer ramus with thin setae in dorsal margin, rami with nail. Telson, about half longer than wide, apical margin very emarginated, with one seta in subterminal margins.

Remarks. Shoemakerella ungulata sp. nov. differs from all other species of Shoemakerella in having an outer plate of maxilliped with a straight inner margin and a rounded outer margin; a strong nail in dactylus of gnathopod 1, the long propodus of gnathopod 2 and a strongly emarginated telson. In addition, it has a dorsally rounded upper lip, with anterodorsal margin straight, anterior margin concave, distal margin with notch, forming a rounded shape and ventral margin concave, different to S. cubensis and S. subchelata .

Figures

FIGURE 14. Shoemakerella ungulata sp. nov.: female, holotype, Camamu Bay, Bahia. Camamu Bay, Bahia, 13°54'S 32°01'W; UFBA 3223. Scale bars: 1.0 mm.

FIGURE 15. Shoemakerella ungulata sp. nov.: female, holotype, Camamu Bay, Bahia. Camamu Bay, Bahia, 13°54'S 32°01'W; UFBA 3223. Scale bars: 0.5 mm for Md; 0.3 for A1-2 and Mp; 0.1 mm for Mx1.

FIGURE 16. Shoemakerella ungulata sp. nov.: female, holotype, Camamu Bay, Bahia. Camamu Bay, Bahia, 13°54'S 32°01'W; UFBA 3223. Scale bars: 0.1 mm for E and rMx2; 0.5 mm for Gn1 and Gn2; 1mm for P3.

FIGURE 17. Shoemakerella ungulata sp. nov.: female, holotype, Camamu Bay, Bahia. Camamu Bay, Bahia, 13°54'S 32°01'W; UFBA 3223. Scale bars: 1.0 mm for P4–P7; 0.3 for U3 and T; 0.5 mm for remain.