Spelaeogammarus sanctus, Bastos-Pereira, Rafaela & Ferreira, Rodrigo L., 2015

Bastos-Pereira, Rafaela & Ferreira, Rodrigo L., 2015, A new species of Spelaeogammarus (Amphipoda: Bogidielloidea: Artesiidae) with an identification key for the genus, Zootaxa 4021 (3), pp. 418-432 : 422-426

Spelaeogammarus sanctus sp. nov.

( Figs 4–8 )

Etymology. The specific epithet sanctus refers to the place in which the new species was collected. The cave is inserted in a religious scenario situated in the municipality of Bom Jesus da Lapa in the Brazilian state of Bahia. Some people of the region say that the cave water is miraculous and thousands of people visit the cave every year looking for this water, which is collected from the species habitat, imposing some potential impacts on the species (see Habitat and Threats).

Material examined. Holotype male, 11.54 mm, July 2013, Gruta dos Milagres cave (13°15'31.45"S 43°25'5.76" W), municipality of Bom Jesus da Lapa, state of Bahia, Brazil, ISLA 10106 ( Fig. 3 ). Ten paratypes were dissected, from which 9 are males and 1 is female. Males mean body length: 12.01 mm (±4.63), female body length: 12.8 mm. July 2013, Gruta dos Milagres cave (13°15'31.45" S 43°25'5.76" W), municipality of Bom Jesus da Lapa, state of Bahia, Brazil, ISLA 10106, ISLA 10107, ISLA 10108, ISLA 10109, ISLA 10110, ISLA 10111, ISLA 10112, MNRJ 25430, MNRJ 25431, MNRJ 25432. Other four paratypes were kept entire, which were collected in the same locality on the same date, ISLA 10114, ISLA 10210, ISLA 10211, ISLA 10212.

Diagnosis ( Fig. 5–8 ). Antenna 1, accessory flagellum 5-articulate. Antenna 2, flagellum 7 to 10-articulate. Maxilla 1, outer lobe, apical margin with 7 multi-cuspidate stout setae. Maxilliped, inner plate, apical margin with 2 Y-shaped stout setae, 3 plumose setae, 2 of them slender setae, 1 submarginal small plumose setae; palp article 3, apical margin bearing a row of small, blunt and plumose nodular setae. Gnathopod 1, basis, anterior margin with 4 to 5 small setae, posterior margin with 15–17 long setae; propodus stout, about 1.3X longer than basis. Gnathopod 2, basis, posterior margin with 19–22 setae. Coxa 5 with 9 to 13 slender setae, posterior lobe round. Coxa 6 with 1 stout seta. Pleopods, inner ramus with 7 to 9 setae. Uropod 3, rami 2X longer than peduncle, outer ramus bearing more than 18 bifid setae. Telson bearing 1 apical and 2 subapical stout setae and 1 plumose seta in each lobe.

Description. Body slender. Head without eyes, slightly deeper than long, about as long as pereonites 1 and 2 combined; rostrum weakly produced, subacute, lateral cephalic lobe subacute, anteroventral corner subquadrate, without setae. Antenna 1, about 0.4X the body length, peduncle slightly shorter than flagellum, article 1 0.7 X as long as articles 2 and 3 combined, ratio of peduncular articles 1–3 = 1.8: 1.4: 1; flagellum with until 22 articles; accessory flagellum 5-articulate, article 5 reduced, total length of accessory flagellum as long as articles 1 to 5 of flagellum combined. Antenna 2, about 0.9X the length of antenna 1, peduncle 2.6 X as long as flagellum, article 2 cone gland rising up to the distal margin of article 3, article 5 0.8X the length of article 4; flagellum 10-articulate.

Upper lip rounded and smooth, with sparse setules apically. Lower lip, inner lobe apically rounded and setulose; outer lobe well developed, broadly rounded, inner distal margin setulose. Left mandible, molar broad, semi-triturative, subcircular; accessory setal row consisting of 4 curved plumose setae, one of them longer and stronger than the others; lacinia mobilis present, well developed, broad and apically multi-cuspidate; incisor multicuspidate; palp 3-articulate, article 1 about twice longer than wide, article 2 slightly robust, about 2.4 X longer than wide, subequal in size in relation to article 3, ventral margin bearing 5 slender setae, article 3 tapering distally, with 2 apical long setae. Right mandible subequal to left mandible, accessory setal row consisting of 4 curved plumose setae, 2 of them longer and stronger than the others. Maxilla 1, inner plate apically round, bearing 3 stout plumose setae on apical margin, about 0.8X the length of outer plate; outer plate subrectangular, bearing 7 multi-cuspidate setae on apical margin; palp 2-articulate, article 2 tapering distally, with a row of setae downwards from the apex to the inner margin. Maxilla 2, short, inner plate about 1.4 X wider than outer plate, apical margin bearing a fringe of plumose setae; outer plate slightly longer than inner plate, apical margin bearing a fringe of slender setae. Maxilliped, inner and outer plates short; inner plate suboval, apical margin with 2 Y-shaped stout setae, 3 plumose setae and 1 slender subapical plumose setae; outer plate slightly elongate, suboval, bearing 5 stout setae apically and 7 slender setae on the inner margin; palp 4-articulate, article 1 about 2.2X longer than wide, article 2, the largest, about 2.1X longer than wide and 1.1X longer than article 3; article 3 apical margin bearing a row of small, blunt and plumose nodular setae, article 4 tapering distally, inner margin setose, a small claw present.

Gnathopod 1, coxa subquadrate; basis stout, about 2.2X longer than wide, anterior margin with 4 to 5 small setae, posterior margin bearing 15 to 17 long setae; isquium subtriangular, distoventral corner with 1 slender seta; merus, ventral margin setose; carpus subtriangular, posterodistal corner produced, without comb-scales, posterodistal margin with a fringe of plumose setae; propodus stout, suboval, about 1.3X longer than basis, palm acute, about 2X longer than posterior margin, covered by a dense fringe of small setae, bearing 10 stout setae; dactylus long, curved, with three small simple setae dorsally, not reaching the palmar corner.

Gnathopod 2, basis subrectangular, about 3.0X longer than wide, posterior margin with 20 long slender setae; isquium slightly wider than long, posterior margin with 1 slender setae; merus subrectangular, about 2.9X longer than wide; carpus subtrapezoidal, about 1.5X longer than wide, posterior margin setose; propodus suboval, slightly elongate, about 1.9X longer than wide, anterior and posterior margins setose, palm acute, about 1.2X longer than posterior margin, covered by a dense fringe of small setae, bearing 7 stout setae, dactylus long, curved, naked, almost reaching the palmar corner.

Pereopod 3, coxa suboval, about 1.4X longer than wide, ventral margin with 8 setae; basis suboval, slightly elongate, anterior and posterior margins without setae, posterodistal corner with 2 small seta; merus, about 2.9X longer than wide, slightly shorter than carpus, anterior margin with 2 stout setae, anterodistal corner with 2 stout setae, posterior margin with 6 setae; carpus elongate, about 4.1X longer than wide, slightly longer than merus, anterior margin with 2 stout setae, posterior margin with 5 stout setae; propodus elongate, about 7.1X longer than wide, slightly longer than carpus, anterior margin with 4 slender setae, posterior margin with bearing 7 lateral sets of stout setae (1-2-2-1-2-1-2); dactylus slightly curved, apical nail present. Pereopod 4 subequal in length to pereopod 3. Pereopod 5, coxa bilobate, anterior lobe well developed, about 1.1X wider than long, with 9–13 slender setae, posterior lobe small, posterior margin slightly concave, bearing 2 stout seta; basis suboval, about 2.1X longer than wide, anterior and posterior margins bearing 3 marginal stout setae and 2–3 distal stout setae; merus about 3.6X longer than wide, anterior margin with 5 slender setae, posterior margin with 2 stout setae; carpus slightly elongate, 7.3X longer than wide, about 1.4X longer than merus, anterior margin with a dense fringe of slender setae, anterodistal corner with two stout setae, posterior margin with 3 sparse slender setae; propodus slightly elongate, about 6.4X longer than wide, about 0.6X the carpus length, bearing 10 lateral sets of stout setae (2-2-2-2-1-1-1-1-1-2), anterior margin with a dense fringe of small slender setae, posterior margin naked; dactylus slightly curved, apical nail present. Pereopod 6 about 1.3X longer than pereopod 5, coxa bilobate, anterior lobe slightly more developed than posterior, anterior margin with 1 stout seta; basis suboval, about 1.8X longer than wide, anterior and posterior margins bearing several stout setae, merus slightly elongate, about 3.3X longer than wide, anterior margin bearing 3 stout setae, posterior margin naked; carpus slightly elongate, 5.5X longer than wide, about 1.2X longer than merus, anterior margin with a dense fringe of slender setae, distal setae longer than the proximal, anterodistal corner with 3 stout setae, posterior margin naked, posterodistal corner with 1 stout seta; propodus slightly elongate, about 9.5X longer than wide, about 0.8X the length of carpus, bearing 15 lateral sets of stout setae (1-2-1-1-1-2-1-1-2-1-2-1-2-2-1), anterior margin with a dense fringe of small slender setae, distal setae longer than the proximal, anterodistal corner with 1 stout seta, posterior margin naked; dactylus slightly curved, apical nail present. Pereopod 7 about 1.2X the length of pereopod 6, coxa subtriangular, about 1.4X wider than long, with 1 posterior stout seta; basis suboval, about 1.7X longer than wide, anterior and posterior margins with several stout setae; ischium slightly stout; merus about 2.8X longer than wide, anterior margin with 4 sets of stout setae (1-2-2-2), posterior margin with 4 stout setae, anterodistal corner with 2 stout setae, posterodistal corner with 3 stout setae; carpus about 4.7X longer than wide, about 1.1X longer than merus, anterior margin with 2 sets of 2 stout setae each, posterior margin with 3 sets of stout setae (3-2-1), anterodistal corner with 4 stout setae, posterodistal corner with 3 stout setae; propodus elongate, about 8.1X longer than wide, about 1.3X longer than carpus, anterior and posterior margins densely setose; dactylus slightly curved, apical nail present.

Pleopod 1, peduncle rectangular, about 6X longer than wide, a pair of hook setae present (probably a cuticular structure of unknown nature); inner ramus 1-articulate, bearing 11 plumose slender setae; outer ramus 3-articulate, subequal in length to inner ramus, article 1, inner margin with 9 plumose setae, outer margin with 18 plumose setae, article 2 with 2 plumose setae, article 3, smallest, with 2 apical plumose setae. Pleopod 2, peduncle rectangular, about 3.5 X longer than wide, a pair of hook setae present; inner ramus 1-articulate, bearing 12 plumose slender setae; outer ramus 3-articulate, slightly longer than inner ramus, article 1, inner margin with 9 plumose setae, outer margin with 16 plumose setae, article 2 with 2 plumose seta, article 3, smallest, with 2 apical plumose setae. Pleopod 3 peduncle rectangular, about 3.2X longer than wide, a pair of hook setae present; inner ramus 1-articulate, bearing 10 plumose slender setae; outer ramus 3-articulate, slightly longer than inner ramus, article 1, inner margin with 9 plumose setae, outer margin with 18 plumose setae, article 2 with 2 plumose seta, article 3, smallest, with 2 apical plumose setae.

Uropod 1, peduncle elongate, about 3.7X longer than wide, bearing 3 ventral stout setae, 4 dorsal stout setae and 2 distolateral stout seta; inner ramus slightly longer than outer ramus, both lanceolate; inner ramus about 0.8X the peduncle length, bearing 3 dorsal, and 4 apical setae; outer ramus bearing 3 dorsal and 3 apical setae. Uropod 2, peduncle about 2.4X longer than wide, bearing 1 dorsal and 2 distolateral stout setae; rami subequal in length, 1.2X longer than peduncle; inner ramus bearing 2 dorsal, 2 ventrodistal, and 3 apical stout setae; outer ramus bearing 2 dorsal, 2 ventral, and 3 apical stout setae. Uropod 3 peduncle short, about 1.7X longer than wide, bearing 1 distolateral stout setae; rami elongate, lanceolate; inner ramus bearing 6 ventral sets stout setae (1-3-3-3-3-2), more than 18 dorsal stout setae and 3 apical stout setae; outer ramus subequal in length in relation to inner ramus, about 2.3X longer than peduncle, bearing 7 dorsal sets of stout setae (1-1-1-2-2-2-2), 4 ventrodistal sets of stout setae (1- 1-2-2), and 2 apical stout setae.

Telson 1.4X longer than wide, apical margin with shallow U-shaped excavation, bearing in each lobe bearing 1 apical and 2 subapical stout setae and 1 plumose seta in each lobe.

Figures

FIGURE 3. Morphometric characters measured to obtain the ratios used on Principal Component Analysis.

FIGURE 4. Spelaeogammarus sanctus sp. nov. Holotype, male 11.54 mm ISLA 10106. Gruta dos Milagres Cave (13 ° 15 ' 31.45 " S 43 ° 25 ' 5.76 " W), municipality of Bom Jesus da Lapa, Bahia state, Brazil.

FIGURE 5. Spelaeogammarus sanctus sp. nov. habitus (body length 11.92 mm). Scale bar: 1 mm.

FIGURE 6. Spelaeogammarus sanctus sp. nov. (body length 11.92 mm). Scale bars: 200 µm.

FIGURE 7. Spelaeogammarus sanctus sp. nov. (body length 11.92 mm). Scale bars: G 1 – G 2 200 µm; P 3 – P 7 500 µm.

FIGURE 8. Spelaeogammarus sanctus sp. nov. Scale bars: U 1, U 2, U 3, telson 200 µm; Pl 1 – 3 400 µm.