Foxiphalus potiguara, Andrade & Senna & Souza-Filho, 2022

Andrade, Luiz F., Senna, André R. & Souza-Filho, Jesser F., 2022, First record and a new species of Foxiphalus Barnard, 1979 (Crustacea: Amphipoda: Phoxocephalidae) from the Atlantic Ocean, with two new records of the family from northeastern Brazil, Papéis Avulsos de Zoologia (Pap. Avulsos Zool., S. Paulo) 62, pp. 1-13 : 3-11

publication ID	https://doi.org/ 10.11606/1807-0205/2022.62.055
publication LSID	lsid:zoobank.org:pub:F76F2FD3-963F-463B-A0CB-55C83C0D748C
DOI	https://doi.org/10.5281/zenodo.10716143
persistent identifier	https://treatment.plazi.org/id/0812BC2D-FA34-FFB1-5F4C-8B57FD48FDE7
treatment provided by	Felipe
scientific name	Foxiphalus potiguara
status	sp. nov.

Treatment

Foxiphalus potiguara View in CoL sp. nov.

( Figs. 1-8 View Figure 1 View Figure 2 View Figure 3 View Figure4 View Figure 5 View Figure 6 View Figure 7 View Figure 8 )

Material examined: Holotype, 1 ♀, 8.3 mm, dissected and illustrated, BPOT Station MT54 R 3, 168 m depth, 2011, state of Rio Grande do Norte, Brazil, 36°44′43.15″W, 04°37′17.08″S ( MOUFPE 15999 View Materials ) GoogleMaps . Allotype, 1 ♂, 8.6 mm, dissected and illustrated, BPOT Station MT54 R 3, 168 m depth, 2011, state of Rio Grande do Norte, Brazil, 36°44′43.15″W, 04°37′17.08″S ( MOUFPE 20003 View Materials ) GoogleMaps . Paratypes: 1 ♀, 7.0 mm, dissected and illustrated, BPOT Station MT54 R 2, 173 m depth, 2011, state of Rio Grande do Norte, Brazil, 36°44′43.15″W, 04°37′17.08″S ( MOUFPE 15962 View Materials ) GoogleMaps ; 1 ♀, 3.8 mm, dissected and illustrated, BPOT Station MT53 R 2, 156 m depth, 2011, state of Rio Grande do Norte, Brazil, 36°34′28.76″W, 04°41′30.23″S ( MOUFPE20004 View Materials ) GoogleMaps ; 1♀, 6.7mm,in70%ethanol, BPOT Station MT54 R 1, 186 m depth,2011,state of Rio Grande do Norte, Brazil, 36°44′43.15″W, 04°37′17.08″S ( MOUFPE 20005 View Materials ) GoogleMaps ; 1 ♀, 6.3 mm, in 70% ethanol, BPOT Station MT54 R 3, 168 m depth, 2011, state of Rio Grande do Norte, Brazil, 36°44′43.15″W, 04°37′17.08″S ( MOUFPE 20006 View Materials ) GoogleMaps .

Diagnosis: Eyes medium to large. Rostrum broad, unconstricted, slightly exceeding the article 2 of antenna 1. Antenna 2 article 4 with three facial rows of robust setae. Upper lip epistome rounded. Lower lip outer lobes with strong and acute shoulder cusps. Right mandible incisor with three teeth, lacinia mobilis bifid. Left mandible incisor with 3 teeth, lacinia mobilis with 4 teeth. Maxilliped inner plate with two apical robust setae; apex of palp article 3 slightly protuberant. Gnathopods 1-2 dissimilar; propodus with one robust seta with accessory seta near palmar corner; palm acute; dactylus with nail. Gnathopod 1 carpus and propodus about twice longer than wide.Gnathopod2carpus shortened,slightly longer than wide; propodus ovate. Pereopods 3-4 carpus posterior margin with distal long robust seta almost reaching the apex of propodus. Pereopod 4 coxa weakly excavated posterodorsally. Pereopod 5 basis tapering distally; merus, carpus, and propodus slender. Pereopod 6 basis broad. Pereopod 7 basis produced posteroventrally, posterior margin serrated. Epimeral plates 1-2 with few plumose setae and rounded corners. Epimeral plate 3 posterior margin weakly crenulated, bearing slender setae. Uropods 1-2 rami with few robust setae, embedded apical nails present. Uropod 1 peduncle with displaced robust seta present. Uropod 3 outer ramus article 2 bearing two plumose setae apically.Telson deeply cleft, each lobe with two dorsolateral plumose setae and one robust and one plumose seta apically.

Description of female: Based on female holotype, 8.3 mm (MOUFPE 15999).

Habitus as in Fig. 1A View Figure 1 . Head ( Fig. 2A, B View Figure 2 ) with medium and ovate eyes, rostrum broad and unconstricted, slightly exceeding the article 2 of antenna 1. Antenna 1 ( Fig. 2C View Figure 2 ) peduncle article 1 about 1.4× longer than wide, dorsal margin with a proximal set of setules, dorsal apex with three setae, ventral margin with seven plumose setae,being one more robust and displaced;article 2 about 0.4× the length of article 1, dorsal apex with two setae, ventral margin with eight pectinate setae medially, facial margin with four setae; article 3 short, ventral margin with 2 setae, facial margin with four plumose setae distally; primary flagellum 11-articulate; accessory flagellum 10-articulate. Antenna 2 ( Fig. 2D View Figure 2 ) articles 1-2 weakly ensiform, article 3 bearing one facial pectinate seta, article 4 facial robust setae formula: 4-4-3, dorsal margin with one robust setae and 2 pectinate medially, ventral margin with 3 plumose setae proximally, many pectinate setae and distally with two smooth robust setae, being one shorter and displaced, article 5 facial margin with a row 5 robust setae, dorsal apex with 3 plumose setae, ventral margin weakly setose with pectinate and plumose setae, bearing a distal row of four robust setae, extending to facial margin; flagellum 13-articulate. Upper lip ( Fig. 2E View Figure 2 ) with two sets of setules on the lower apex, epistome rounded. Lower lip ( Fig. 2F View Figure 2 ) inner lobes naked, outer lobes with strong and acute shoulder cusps. Mandibles ( Fig. 3 View Figure 3 A-B) incisor with three teeth, lacinia mobilis bifid (right) and with four teeth (left), accessory setal row with eight robust multicuspidate setae and short plumose setae between them, molar as a hump with a triturative surface, with five robust setae, bearing a brush of setules, palpar hump small; palp 3-articulate, article 1 short, article 2 lateral margin with a brush of setules proximally and three setae medially, medial margin with four setae, article 3 with two setae, apex oblique, with 10 pectinate setae. Maxilla 1 ( Fig. 2G View Figure 2 ) inner plate with five apical plumose setae, lateral margin setulose; outer plate with 11 robust setae, being four serrate, six bifid and one more robust and smooth; palp 2-articulate, article 2 with four pectinate setae, medial margin with row of setules and two setae, apex with one robust seta. Maxilla 2 ( Fig. 2H View Figure 2 ) inner plate subequal to outer, with 11 plumose setae, lateral margin setulose; outer plate lateral margin with row of setules and four short apicolateral plumose setae, apex with eight bipectinate setae. Maxilliped ( Fig. 2I View Figure 2 ) inner plate with seven plumose setae and 2 apical robust setae; outer plate with medial margin with a row of nine papposerrate setae extending to apex,lateral margin with seven pappose setae extending to apex; palp article 2 with one apicolateral seta, medial margin weakly setose, article 3 lateral margin with one pectinate seta medially and three distally, medial and facial margins weakly setose, article 4 elongated, with accessory seta, nail present.

Gnathopod 1 ( Fig. 4A View Figure4 ) coxa subrectangular, ventral margin convex, with nine pectinate setae; basis weakly setose; ischium short and subrectangular, posterodistal corner with three pectinate setae; merus subtriangular, posterior margin with four distal pectinate setae, facial margin with two setae; carpus about 2× longer than wide, anterior margin with one distal seta, posterior margin weakly setose, with pectinate setae; propodus about 1.9× longer than wide and 1.2× longer than carpus, weakly setose, posterior margin with one robust seta with accessory seta near palmar corner; palm acute, covered with short setae, palmar hump medium; dactylus reaching the palmar corner, nail present. Gnathopod 2 ( Fig. 4B View Figure4 ) coxa subrectangular, ventral margin with 10 pectinate setae, basis weakly setose; ischium short and subquadrate, posterodistal corner with three setae; merus posterior margin six setae, facial margin with two setae; carpus short, anterior margin with one distal seta; propodus ovate, weakly setose, about 1.5× longer than wide, posterior margin with one robust seta with accessory seta near palmar corner, palmar hump large; dactylus reaching the palmar corner, nail present. Pereopod 3 ( Fig. 4C View Figure4 ) coxa subrectangular, ventral margin with nine pectinate setae;basis weakly setose, posterodistal corner with five pectinate setae; ischium short and subrectangular, posterodistal corner with five setae; merus about 2.6× longer than wide, anterior and facial margins with three distal pectinate setae each, posterior margin moderately; carpus facial margin with a row of four pectinate setae, posterior margin moderately setose, distally with a short displaced robust seta with accessory seta, distal long robust seta almost reaching the apex of propodus; propodus with eight robust setae with accessory setae and one short seta; dactylus about 55% the length of propodus, bearing one short plumose seta medially, nail present. Pereopod 4 ( Fig. 4D View Figure4 ) coxa posterior margin expanded, posterodorsal margin weakly excavated, ventral margin with 11 pectinate setae; remaining segments very similar to pereopod 3, differing only by some setae patterns. Pereopod 5 ( Fig. 5A View Figure 5 ) coxa bilobated, posterior lobe with eight posteroventral pappose setae; basis about 1.8× longer than wide, anterior margin with nine setae, anterodistal corner with five setae; ischium short and subrectangular,anterodistal corner with a row of five pectinate setae extending to facial margin; merus robust setae formula: 1-2-3-5-5, anterior margin with plumose setae, posterior margin with few pappose setae; carpus robust setae formula: 2-4-3-5-4, anterior and posterior margins with plumose and pappose setae respectively; propodus robust setae formula: 3-4-2-2; dactylus about 65% the length of propodus, bearing one proximal short plumose seta. Pereopod 6 ( Fig. 5B View Figure 5 ) coxa posteroventral margin with seven pappose setae; basis broad, about 1.2× longer than wide, anterior margin with three setae proximally, medially with five sets of pectinate setae, anterodistal corner with six pectinate setae; ischium short and subtriangular, anterodistal corner with five setae; merus anterior margin weakly setose, with 5 sets of robust setae: 1-2-3-2-3, posterior margin with pappose setae and three sets of robust setae: 2-3-3; carpus anterior margin with three sets of robust setae: 4-5-7, posterior margin with few pappose setae, one robust seta medially and four distally;propodus anterior margin with four sets of robust setae: 2-4-4-3, posterior margin with few pappose setae and four robust setae; dactylus about 50% the length of propodus. Pereopod 7 ( Fig. 5C View Figure 5 ) coxa subrectangular, posterior margin with six pappose setae; basis slightly longer than wide, produced posteroventrally, posterior margin serrated, anterior margin with five setae proximally and three short robust setae medially, anterodistal corner with one robust seta; ischium subquadrate, anterodistal corner with three setae; merus anterior margin moderately setose, posterior margin with three plumose and one smooth setae; carpus anterior margin with few slender and robust setae, posterior margin with pectinate setae; propodus anterior and posterior margins with three sets of setae each; dactylus about 60% the length of propodus, bearing one proximal short plumose seta.

Epimeral plate 1 ( Fig. 6A View Figure 6 ) anterior margin with two plumose setae, anteroventral corner with a row of three plumose setae extending to facial margin. Epimeral plate 2 ( Fig. 6B View Figure 6 ) anterior margin with two plumose setae, facial margin with a row of six plumose setae. Epimeral plate 3 ( Fig. 6C View Figure 6 ) anterior margin with two plumose setae, ventral margin with two setae, posterior margin weakly crenulated, with eight setae. Urosomite 1 ( Fig. 1A View Figure 1 ) bearing a ventral tuft of setae. Uropod 1 ( Fig. 6D View Figure 6 ) peduncle longer than rami, about 2.8× longer than wide, dorsomedial margin with one slender and five robust setae, dorsolateral margin with four robust setae, displaced robust setae present; both rami bearing one embedded apical nail; outer ramus slightly longer than inner, dorsal margin with four robust setae;inner ramus dorsal margin with two robust setae. Uropod 2 ( Fig. 6E View Figure 6 ) peduncle longer than rami, about 2.1× longer than wide, dorsomedial corner with one robust seta, dorsolateral margin with seven robust setae; both rami bearing one embedded apical nail; outer ramus slightly longer than inner, dorsal margin with three robust setae; inner ramus dorsal margin with one robust seta. Uropod 3 ( Fig. 6F View Figure 6 ) peduncle about 1.5× longer than wide, dorsomedial margin with one robust and one short seta, dorsolateral margin with one distal robust seta, ventral margin with a distal row of four robust setae; outer ramus 1.4× longer than inner, article 1, ventrally with three sets of two robust and one plumose seta, dorsal margin with three plumose setae, article 2 about 0.3× the length of article 1, bearing two apical plumose setae, inner ramus about 0.6× the length of outer, with few plumose setae, being two placed apically. Telson ( Fig. 6I View Figure 6 ) about 85% cleft, each lobe with two dorsolateral plumose setae plus a short, one robust and one plumose seta apically.

Description of male: Based on male allotype, 8.6 mm (MOUFPE 20003).

Head ( Fig. 7 View Figure 7 A-B) with large and ovate eyes, rostrum broad and unconstricted, slightly exceeding the article 2 of antenna 1. Antenna 1 ( Fig. 7C View Figure 7 ) peduncle article 1 dorsal apex with one plumose and two smooth setae, ventral margin with 13 plumose setae and a distal row of setules; article 2 dorsal apex with two setae, ventral margin with eight pectinate setae,facial margin with two plumose and five pectinate setae, article 3 ventral margin with two setae, facial margin with four setae, being two plumose; primary flagellum 12-articulate; accessory flagellum 9-articulate. Antenna 2 ( Fig. 7D View Figure 7 ) peduncle article 3 bearing one long and one short facial seta, dorsal margin with a row of setules; article 4 facial robust setae formula: 3-4-3, dorsal margin with one robust, one long and eight smooth setae medially, proximally and distally with sets of setules, ventral margin with five plumose setae proximally and pectinate setae medially, distally with one displaced robust long seta; article 5 facial robust setae formula: 3-2, dorsal margin with four brushes of setules and one distal calceolous, ventral margin with few slender and plumose setae, facial margin with two distal robust setae; flagellum 28-articulate, with five calceoli.

Gnathopod 1 ( Fig. 7E View Figure 7 ) coxa weakly expanded distally, ventral margin convex, with 11 setae; basis weakly setose, ischium short and subrectangular; merus posterior and facial margins with three and one pectinate setae respectively; carpus anterior margin with one distal seta, posterior margin with nine pectinate setae; propodus about 2.5× longer than wide and 1.3× longer than carpus,weakly setose,posterior margin with one robust seta with accessory seta near palmar corner; palm acute, covered with short setae, palmar hump medium; dactylus reaching the palmar corner, nail present. Gnathopod 2 ( Fig. 8A View Figure 8 ) coxa subrectangular, ventral margin with nine setae; other segments weakly setose and very similar to gnathopod 1; propodus ovate, weakly setose, about 1.8× longer than wide, posterior margin with one robust seta with accessory seta near palmar corner, palmar hump large;dactylus exceeding the palmar corner, nail present. Pereopod 7 ( Fig. 8B View Figure 8 ) coxa subtriangular, posterior margin with six setae; basis 1.3× longer than wide, posterior margin weakly serrated, facial margin with few short setae; carpus copulatory spines subequal, proximally serrated, strongly tapering distally.

Epimeral plate 1 ( Fig. 8C View Figure 8 ) anteroventral corner with a row of four plumose setae, increasing in length, ventral margin almost straight, posterior margin convex. Epimeral plate 2 ( Fig. 8D View Figure 8 ) anterior margin with seven sete, anteroventral corner weakly expanded, ventral margin with a shallow concavity, posterior margin with two notches, one of them bearing one seta. Epimeral plate 3 ( Fig. 8E View Figure 8 ) anterior margin with seven short setae, ventral margin with three setae, posterior margin with 11 pectinate setae. Uropod 3 ( Fig. 8F View Figure 8 ) peduncle ventral margin with five distal robust setae, dorsal margin with one short and one robust seta; outer ramus slightly longer than inner, article 1 ventral margin with three sets of one robust and one long plumose seta, dorsally covered with plumose setae, article 2 about 0.2× the length of article 1, beating two apical plumose setae, inner ramus strongly setose with plumose setae,with two apical plumose setae.

Etymology: The specific epithet is given after the Potiguar Basin, type-locality of the new species. This name is derived from an indigenous Tupi word "poti′war″ or "potiguar″ that means "the one who eats shrimp″. The epithet is used as a noun in apposition.

Type locality: Continental slope of Rio Grande do Norte state, Brazil (36°44′43.15″W, 04°37′17.08″S).

Distribution and bathymetric range: The species is found off the coast of the state of Rio Grande do Norte, from 156 to 186 m depth ( Fig. 9 View Figure9 ).

Remarks: Among the species of the genus, Foxiphalus potiguara sp. nov. is most morphologically similar to F.similis due to characters such as: lower lip outer lobes with strong shoulder cusps; mandible right and left incisors with three teeth, molar with five robust setae; maxilliped palp with slender nail; pereopod 5 merus and carpus narrow; uropod 1 peduncle with strong displaced robust setae; telson without dorsolateral robust setae. However, the new species can be distinguished by F. similis by the following (characters of F.similis in parenthesis): maxilla 1 inner plate with five apical setae (three to four apical setae); mandible molar as a hump with a triturative surface (as a hump, non-triturative); maxilliped inner plate with two apical robust setae (one apical robust seta); pereopod 5 basis narrow, tapering distally (broad, not tapering); male copulatory spine without distal setules (distally setulose); urosomite 1 of female with ventral tuft of setae (without); telson with each lobe bearing one apical robust seta (two robust setae).

Furthermore, F. potiguara sp. nov., presents the longer rostrum withing the genus, slightly exceeding the apex of the second article of antenna 1, whereas the other species have it only reaching the apex of this article. In addition, F. potiguara sp. nov. has the largest discrepancy between gnathopods 1-2 among its congeners, being the second gnathopod stronger than the first. The new species also shares with only another species ( F. aleuti ) the presence of two apical robust setae on the inner plate of maxilliped. Thus F. potiguara sp. nov. can be distinguished by the latter by presenting: mandibular molar with less robust setae; gnathopods 1-2 with more shortened carpus and stronger propodus; pereopod 3 carpus posterior margin with longer distal long robust seta; uropod 3 outer ramus articles 1 and 2 longer in relation to the peduncle; telson lobes presenting only one apical robust seta.

It is important to highlight that during the analysis of the material, subtle and expected differences were found among the female individuals. However, it was possible to notice an interesting contrast between the inner and outer rami of the third uropod in relation to each individual′s length, and consequently reflecting maturity stage. The smallest individual (female paratype MOUFPE 20004) presents a less setose uropod 3 ( Fig. 6H View Figure 6 ), very short inner ramus on uropod 3 with one apical slender seta, about 0.3× the length of outer, and article 2 of outer ramus about 0.4× the length of article 1. A medium-sized individual (female paratype MOUFPE 15962) presents uropod 3 ( Fig. 6G View Figure 6 ) more setose than the smaller one, with inner ramus about 0.4× the length of outer, bearing two apical plumose setae and article 2 of outer ramus about 0.3× the length of article 1.Whereas the bigger individual (female holotype MOUFPE 15999) presents a fully developed inner ramus on uropod 3 ( Fig.6F View Figure 6 ),reaching 0.6× the length of outer, bearing two apical plumose setae and article 2 of outer ramus about 0.3× the length of article 1.