Ampithoe robustimana, Andrade, Luiz F. & Senna, André R., 2017

Andrade, Luiz F. & Senna, André R., 2017, Two new species of Ampithoidae (Crustacea: Amphipoda) from northeastern Brazil, Zootaxa 4282 (3), pp. 487-500 : 488-494

Ampithoe robustimana sp. nov.

( Figs 1–5 )

Material examined. Holotype, male, dissected and drawn, 9.4 mm, 28 March 2013, Pacheco Beach , municipality of Caucaia, Ceará state, Brazil, in sandstone reefs in the intertidal zone, J. Alves col., CRFFP 76 . Paratypes: 1 female, dissected and drawn, 10.8 mm, same collection data, CRFFP 77; 10 females + 3 males, same collection data, CRFFP 78.

Diagnosis. Gnathopod 1 basis lobate; carpus with subacute projection; propodus elongated, robust and subrectangular; palm almost transverse with a mid-palmar subquadrate tooth. Gnathopod 2 basis lobate; propodus elongated, robust and subrectangular; palm almost transverse. Pereopod 3 narrow. Pereopod 4 narrow; merus subrectangular. Pereopods 5–7 prehensile. Epimeron 3 posteroventral corner with an acute tooth. Uropod 1 with a short setal fringe. Uropod 3 with 6 distal stout setae. Telson distally convex with two apical cusps.

Description. Based on holotype male 9.4 mm, CRFFP 76.

Head. Eyes rounded and well developed. Antenna 1 weakly setose, longer than antenna 2; peduncular article 1 as long as article 2, article 2 about 4.9 × longer than article 3; flagellum 34-articulate. Antenna 2 peduncular article 5 subequal to article 4; flagellum 31-articulate. Upper lip rounded, apically setose. Lower lip notched; lateral lobe longer than medial. Right mandible molar triturative with a long plumose setae; incisor and lacinia mobilis multicuspidate; accessory setal row with 6 stout multicuspidate setae; palp 3-articulate, article 2 subequal to article 3 and 2 × longer than article 1, article 3 with 12 pectinate long setae apically. Left mandible incisor and lacinia mobilis multi-cuspidate; accessory setal row with 5 stout multicuspidate setae; Maxilla 1 inner plate small and subtriangular, with 2 long plumose setae; outer plate with 8 stout multicuspidate setae apically; palp 2-articulate, inner margin with 7 pectinate setae, apical margin with 6 regular and 3 pectinate setae. Maxilla 2 inner plate 3.5 × longer than wide, inner margin covered with long plumose setae, apical margin covered with small setules, long setae and 7 robust setae; outer plate slightly longer than inner plate, about 2.5 × longer than wide, inner and outer margins covered with small setules and long setae. Maxilliped inner plate small and subtriangular with 2 long setae; outer plate 1.6 × longer than wide, inner margin covered with small stout setae and trifid stout setae, outer and apical margin with 14 long plumose setae and 2 apically pectinate stout setae; palp 4-articulate, about 1.6 × longer than outer plate; article 1 with 2 setae on the outer margin, article 2 broad, with a row of long setae on the inner margin, article 3 inner margin with long regular and plumose setae, article 4 naked, nail present.

Pereon. Gnathopod 1 weakly setose; coxa produced anteriorly, ventral margin with row of tiny setules; basis 3.3 × longer than wide, anterior margin with few setules, posterodistal lobe small and rounded with 4 short stout setae; ischium small and subtriangular; merus produced to form a small subacute lobe with pectinate long setae; carpus subtriangular, slightly wider than long, anterior margin with 7 short setae and a tuft of setae distally, posterior margin with a tuft of pectinate setae; propodus elongated, robust and subrectangular, about 2.1 × longer than wide, posterior margin with 2 tufts of long setae; palm almost transverse, with a mid-palmar subquadrate tooth; dactylus longer than palm. Gnathopod 2 weakly setose; coxa ventral margin with row of tiny setules; basis 3.3 × longer than wide, posterodistal lobe small and rounded with 5 short stout setae; ischium small and subquadrate, posterior margin with 3 short setae; merus produced to form a small subacute lobe with 6 pectinate setae; carpus subtriangular, anterior margin with 4 short setae and a row of 5 setae distally, posterior margin with a row of ten long pectinate setae; propodus elongated, robust and subrectangular, about 2.1 × longer than wide, anterior margin with sets of short setae (1-2-3-3-2-3), with a tuft of very elongated slender setae distally, posterior margin with sparse setae; palm almost transverse; dactylus subequal to palm. Pereopod 3 coxa ventral margin with row of tiny setules; basis 2.4 × longer than wide, anterior margin with 2 stout setae distally, posterior margin with sparse long and short setae; ischium small and subquadrate, produced posterodistally to form a subquadrate lobe, posterior margin with 4 short setae; merus subrectangular, about 1.4 × longer than wide, anterior margin with 1 stout short setae and a tuft of setae distally, posterior margin with a tuft of 5 setae and a row of 5 setae distally; carpus subrectangular, anterior margin with 1 stout short setae and a tuft of setae distally, posterior margin with sparse short and long setae; propodus 3.2 × longer than wide with sparse short and long setae on both margins; dactylus curved. Pereopod 4 very similar to pereopod 3, differing only by some arrangements of setae on basis, merus and carpus. Pereopod 5 coxa ventral margin with row of tiny setules; basis subovoid as long as wide; ischium small and subquadrate, produced to form a small rounded lobe; merus subrectangular, about 1.5 × longer than wide; propodus prehensile, anterior margin with 7 stout setae with accessory setae, lateral margin with a robust setae near dactylus insertion, posterior margin with sparse long and short setae, dactylus curved. Pereopod 6 coxa ventral margin with 2 setae; basis subovoid, about 1.3 × longer than wide, anterior margin with 5 short stout setae, posterior margin with 1 stout setae distally; ischium small and subquadrate; merus and carpus very similar, with sparse long and short setae; propodus prehensile, anterior margin with 4 stout setae with accessory setae and 4 long plumose setae, lateral margin with 1 robust setae near dactylus insertion, posterior margin with sparse short and long setae and a tuft of long setae distally; dactylus curved. Pereopod 7 coxa absent; basis 1.5 × longer than wide, anterior margin with sparse setae, posterior margin with row of setules and a stout setae distally; ischium small and subquadrate; merus and carpus very similar, with sparse long and short setae; propodus prehensile, anterior margin with 6 stout setae with accessory setae, lateral margin with 1 robust setae near dactylus insertion, posterior margin with sparse short and long setae and a tuft of long setae distally; dactylus curved.

Pleon. Epimeron 1 anterior margin slightly concave. Epimeron 2 subrectangular, anterior margin slightly concave. Epimeron 3 posteroventral corner with an acute tooth. Uropod 1 peduncle 3.1 × longer than wide, with a short setal fringe and 13 stout setae; inner ramus 1.2 × longer than outer ramus, with 7 marginal and 4 apical stout setae; outer ramus with 10 marginal and 4 apical stout setae. Uropod 2 peduncle 2.4 × longer than wide, with 3 stout setae, setal fringe absent; inner ramus slightly longer than outer ramus, with 6 marginal and 4 apical stout setae; outer ramus with 8 marginal and 4 apical stout setae. Uropod 3 peduncle 2.4 × longer than wide, with 6 stout and 7 long plumose setae distally; inner ramus subequal to outer ramus, with 9 long and 4 stout setae distally; outer ramus with 2 large recurved distal robust setae. Telson subtriangular and distally convex, with 2 small cusps and 4 apical setae on each side.

Female (sexually dimorphic characters). Based on paratype, female, 10.8 mm, CRFFP 77. Gnathopod 1 weakly setose; coxa produced anteriorly, ventral margin with row of tiny setules; basis 2.8 × longer than wide, posterior margin with 5 long setae, posterodistal lobe small and rounded with 5 short stout setae; ischium small and subquadrate; merus produced to form a small rounded lobe with pectinate long setae; carpus subtriangular, slightly longer than wide, posterior margin with row of pectinate setae; propodus subrectangular, about 1.7 × longer than wide, anterior margin with sparse short and long setae, posterior margin setose; palm acute, defined by 1 stout setae; dactylus longer than palm, inner margin serrated. Gnathopod 2 weakly setose; coxa ventral margin with row of tiny setules; basis 3 × longer than wide, posterior margin with 4 long setae, posterodistal lobe small and rounded with 5 short stout setae; ischium small and subquadrate; merus produced to form a small rounded lobe with long setae; carpus subtriangular, slightly wider than long, anterior margin with 3 short stout setae and a tuft of long setae distally, posterior margin with a row of long setae; propodus subrectangular, about 1.4 × longer than wide, anterior margin with sparse short and long setae, posterior margin setose; palm almost transverse, slightly concave, defined by 1 stout setae; dactylus slightly longer than palm, inner margin serrated.

Etymology. The specific epithet is related to the robust size of propodus on both gnathopods.

Remarks. Ampithoe robustimana sp. nov. can be recognized between the Ampithoe recorded from Brazil since A. ramondi Audouin, 1826 is characterized by a digitiform process on the male gnathopod 2 palm while Ampithoe robustimana sp. nov. has an entire palm on gnathopods. It can also be distinguished from A. seticoxae Serejo & Licínio, 2002 by having antenna 1 longer than antenna 2 and not presenting a posteroventral tuft of setae on coxae 1–4 and differs from A. suapensis Correia et al., 2016 by not presenting a distoventral process on the peduncle of uropod 1.

By presenting a robust and subrectangular gnathopod 2 propodus and an almost transverse palm, Ampithoe robustimana sp. nov. can be placed within the Ampithoe valida Smith, 1873 species complex. However, the new species can be distinguished from other species in the complex by presenting gnathopod 1 elongated, robust and subrectangular with a mid-palmar subquadrate tooth.

Habitat. Ampithoe robustimana sp. nov. occurs in sandstone reefs in the intertidal zone.

Distribution. Known only from Pacheco Beach, Caucaia, Ceará state, Brazil.

Figures

FIGURE 1. Ampithoe robustimana sp. nov. Holotype, male, 9.4 mm, CRFFP 76, Pacheco Beach, municipality of Caucaia, Ceará state, Brazil. Scale bar: 3.0 mm.

FIGURE 2. Ampithoe robustimana sp. nov. Holotype, male, 9.4 mm, CRFFP 76, Pacheco Beach, municipality of Caucaia, Ceará state, Brazil. Scale bars: 0.5 mm for A 1 – 2; 0.2 mm for the remainder.

FIGURE 3. Ampithoe robustimana sp. nov. Holotype, male, 9.4 mm, CRFFP 76, Pacheco Beach, municipality of Caucaia, Ceará state, Brazil; paratype, female, 10.8 mm, CRFFP 77, Pacheco Beach, municipality of Caucaia, Ceará state, Brazil. Scale bars: 0.5 mm.

FIGURE 4. Ampithoe robustimana sp. nov. Holotype, male, 9.4 mm, CRFFP 76, Pacheco Beach, municipality of Caucaia, Ceará state, Brazil. Scale bars: 0.5 mm.

FIGURE 5. Ampithoe robustimana sp. nov. Holotype, male, 9.4 mm, CRFFP 76, Pacheco Beach, municipality of Caucaia, Ceará state, Brazil. Scale bars: 0.5 mm for Eps 1 – 2; 0.2 mm for the remainder.