Peramphithoe conlanae, Souza-Filho, Jesser F., Guedes-Silva, Elkênita & Senna, André R., 2016

Souza-Filho, Jesser F., Guedes-Silva, Elkênita & Senna, André R., 2016, New record of the genus Peramphithoe Conlan & Bousfield, 1982 (Amphipoda: Ampithoidae) from Brazilian coast, with description of a new species, Zootaxa 4136 (1), pp. 188-194 : 189-193

Peramphithoe conlanae sp. nov.

( Figures 1–3 )

Material examined. Holotype male (2.8 mm), Todos os Santos Bay, #M3, 12º46.371’S 38º33.533’W, 3 m depth, O. Falcão col., MNRJ 15757. Paratypes: 2 females, Todos os Santos Bay, #M3, 12º46.371’S 38º33.533’W, 22 May 1997, 3 m depth, O. Falcão col., MNRJ 25510.

Diagnosis. Gnathopod 1, coxa deeper than wide, anteroventral angle subacute and not produced forward, propodus subrectangular, palm transverse, convex, minutely serrate (extending first part of posterior margin), with a large robust seta defining palm, Gnathopod 2 basis lacking anterodistal lobe, propodus subovate, 1.6 × longer than wide, palm acute, concave and setose; posterior margin shorter than palm (~1/2). Pereopods 5-6 articles expanded. Uropod 1 peduncle with subacute distoventral spur about 1/3 of outer ramus. Uropod 2 peduncle without distoventral spur. Uropod 3 peduncle long, length 1.9 × longer than wide. Telson subtriangular, distally rounded, telsonic cusps of medium size.

Description. Based on holotype male (2.8 mm, MNRJ 15757). Antenna 1 missing, Antenna 2 peduncle article 4 slightly longer than article 5 (1.2 x); flagellum shorter than peduncle, 9-articulate, article 1 and 2 subequal in length and about twice the length of the others. Upper lip distally setose. Mandibles left and right incisor with 9 teeth; lacinia mobilis asymmetrical, left with 6 teeth, right with microdentate; accessory setal rows, left with 6 serrate setae, right with 10 serrate setae; molars fully triturative; palp present, well developed, article 2 longer the article 3 (1.2 x), article 3 with 5 long pectinate setae distally. Lower lip outer lobe with a shallow distal notch; mandibular lobes subacute apically. Maxilla 1 inner plate with 1 seta; outer plate with 9 strong setal-teeth; palp 2- articulate with 4 large apical robust setae and 1 subapical seta. Maxilla 2 inner plate slightly narrow than outer, both with marginal plumose setae. Maxilliped inner plate subrectangular, reaching end of article 1 of palp, with 1 large nodular setae and marginal and apical plumose seta; outer plate subovate, reaching halfway of article 3, with 3 robust setae along apical margin, with 7 robust setae along medial margin; palp large, 4-articulate; article 1, with 2 pappose setae on laterodistal angle; article 2 about 1.5 × of article 3, medial margin with pappose setae; article 3 slightly longer then article 4, with pappose setae on both medial and distal margin; article 4 curved with nail very short.

Gnathopod 1, coxa deeper than wide, anteroventral angle subacute and not produced forward, ventral margin with a row of slender setae, posteroventral angle with 2 long pappose setae; basis without anterodistal lobe, posterior margin with 2 long setae; carpus subequal in length to propodus, posterior margin rounded and densely setose; propodus subrectangular, palm transverse, convex, minutely serrate (extending first part of posterior margin), with a large robust seta defining palm; dactylus long, inner margin serrate and 1.8 × palm length. Gnathopod 2 coxa deeper than wide, subovate, ventral margin with a row of slender setae, posteroventral angle with 3 long pappose setae; basis lacking anterodistal lobe, posterior margin with 4 long setae; merus quadrate with a tuft of setae on posterodistal angle; carpus subtriangular, short, about 0.4 × shorter than propodus, posterior margin with small lobe; propodus subovate, 1.6 × longer than wide, palm acute, concave and setose; posterior margin shorter than palm (~1/2); dactylus reaching palm corner, inner margin smooth. Pereopod 3 basis inflated and subovate, 1.5 × wider than long, posterior margin with 5 slender setae; merus with anterior margin expanded, subequal in length to carpus; carpus slender and subrectangular; propodus 3.4 × wider than long, dactylus robust and curved. Pereopod 4 basis inflated and subovate, 1.5 × wider than long, posterior margin with 3 slender and long setae; merus with anterior margin expanded, subequal in length to carpus; carpus slender and subrectangular; propodus 3.1 × wider than long, dactylus robust and curved. Pereopod 5 articles expanded; basis suboval, almost as long as wide, anterior and posterior margins with small slender setae; ischium short, 1.6 × wider than long; merus subquadrate, almost as long as wide; carpus subequal in length to merus and almost as long as wide; propodus 2.2 × longer than wide, 1.3 × longer than carpus, posterior margin with row of 5 robust setae; dactylus robust and curved. Pereopod 6 articles expanded; basis subrectangular, longer than wide (1.4 x), posterior margin with 5 small slender setae; ischium short, 1.4 × wider than long; merus subquadrate, slightly longer than wide (1.2 x); carpus subequal to merus and slightly longer than wide (1.4 x); propodus 1.4 × longer than carpus, posterior margin with row of 6 robust setae; dactylus robust and curved. Pereopod 7 missing.

Epimera 1–3 posteroventral angle rounded. Uropod 1 peduncle with subacute distoventral spur about 1/3 of outer ramus, with long simple setae on ventrolateral margin, with 2 dorsolateral robust setae and 5 dorsomedial robust setae; inner ramus bearing 1 dorsal halfway robust seta and 3 apical robust setae; outer ramus with 3 lateral and 4 apical robust setae. Uropod 2 peduncle without subacute distoventral spur, with 1 dorsomedial robust seta; inner ramus bearing 3 dorsal robust setae and 4 apical robust setae; outer ramus with 3 lateral and 4 apical robust setae. Uropod 3 peduncle long, length 1.9 × longer than wide, ventral margin with proximal patch of setule and 3 distal slender setae, dorsal margin with 4 slender setae and 5 distal slender and long setae; inner ramus 0.4 × length of peduncle, subovate, with 8 apical slender setae and 2 apical robust setae; outer ramus dorsal margin with patch of small conical spines, with 2 large curved upwards robust setae. Telson subtriangular, distally rounded, with 2 dorsolateral plumose setae and 3 subapical setae on each margin, telsonic cusps of medium size.

Sexually dimorphic characters. Based on paratype female (MNRJ 25510). Antenna 1 flagellum long 3.2 × of peduncle length, 23-articulate. Antenna 2 flagellum very short, 0.7 × of peduncle length, 7-articulate. Gnathopod 1, coxa deeper than wide, anteroventral angle rounded and not produced forward, ventral margin with a row of slender setae and 5 long setae; basis without anterodistal lobe, posterior margin with 3 long setae; carpus slightly shorter than propodus (1.2 x), posterior margin truncate and densely setose; propodus subrectangular, palm transverse, convex, minutely serrate (extending first part of posterior margin), with a large robust setae defining palm; dactylus long, inner margin serrate and twice the palm length. Gnathopod 2, coxa deeper than wide, ventral rounded and with a row of slender setae and 6 long setae; basis without anterodistal lobe, posterior margin with 4 long setae; carpus subtriangular, shorter than propodus (0.8 x), posterior margin rounded and densely setose; propodus subrectangular, palm transverse, convex, minutely serrate, without a large robust seta defining palm; dactylus long, inner margin serrate and 1.9 × palm length.

Etymology. Named in honor to Dr. Kathleen E. Conlan, from Canadian Museum of Nature for her contribution on the taxonomy of the family Ampithoidae .

Type locality. Known only for the type locality, Todos-os-Santos Bay, Bahia, Brazil (12º46.371’S 38º33.533’W).

Remarks. Peramphithoe conlanae sp. nov. fits well with all diagnostics characters of the genus. Among all species of this genus, the new species resembles P. t e a (Barnard, 1965) and P. aorangi (Barnard, 1972) from New Zealand, and P. baegryoeongensis Kim & Kim, 1988 and P. chujaensis Kim et al., 2012 from Korea by the oval propodus of male gnathopod 2 with palm concave. However, P. conlanae sp. nov. can be distinguished from P. t ea by the coxa of gnathopod 1 with anteroventral angle acute (vs rounded angle), palm of gnathopod 2 lacking process and not serrate, basis of pereopods 3 and 4 with posterior margin less setose, pereopod 5 with basis less expanded almost as long as wide (vs wider than long), uropod 3 bearing only 2 apical robust setae on inner ramus (vs 6).

Peramphithoe conlanae sp. nov. differs from P. aorangi by the basis of gnathopod 1 with only 2 long setae on posterior margin (vs 5), palm micro-serrate (vs smooth), gnathopod 2 (adult male) palm less concave and dactylus less curved, uropod 3 bearing 2 apical robust setae on inner ramus (vs 1). It can be distinguished from P. baegryoeongensis in having an acute anteroventral angle of coxa 1, the ischium and merus of pereopod 6 inflated and wider than long (1.4 × and 1.2 ×, respectively, telson with lateral margins not concave. Also, P. conlanae sp. nov. is readily differentiated from P. chujaensis Kim et al., 2012 by the less setose gnathopods 1–2, not presenting very expanded ischium and merus of pereopods 5-7, distoventral process on uropod 1 about 1/3 of outer ramus (vs 1/2 of outer ramus).

Figures

FIGURE 1. Peramphithoe conlanae sp. nov., holotype male (2.8 mm), Todos os Santos Bay, MNRJ 15757. Scale bars = 0.1 mm.

FIGURE 2. Peramphithoe conlanae sp. nov., holotype male (2.8 mm), Todos os Santos Bay, MNRJ 15757. Paratype female, MNRJ 25510. Scale bars = 0.1 mm.

FIGURE 3. Peramphithoe conlanae sp. nov., holotype male (2.8 mm), Todos os Santos Bay, MNRJ 15757. Scale bars = 0.1 mm.