Fuegiphoxus fuegiensis ( Schellenberg, 1931 )

Fuegiphoxus fuegiensis ( Schellenberg, 1931) View in CoL

( Figs. 8–12 View Figure 8 View Figure 9 View Figure 10 View Figure 11 View Figure 12 )

Parharpinia fuegiensis Schellenberg, 1931: 78–80 View in CoL , fig. 40. — Stephensen, 1949: 5–6.

Paraphoxus fuegiensis . — J.L. Barnard, 1958a: 146. — J.L. Barnard, 1958b: 118. — J.L. Barnard, 1960: 186, 195, 271–273, 282, 290, pl. 42, figs. A–R. — Sanderson, 1973: 43. — Thurston, 1974: app. C.

Paraphoxus feugiensis (sic). — Lowry and Bullock, 1976: 126.

Wildus? fuegiensis . — Barnard and Drummond, 1978: 18, 32, 134, 144–145.

Fuegiphoxus fuegiensis View in CoL . — Barnard and Barnard, 1980: 853–858, figs.1–3. — Barnard and Barnard, 1990: 50. — Barnard and Karaman, 1991: 610. — González, 1991: 61. — De Broyer and Jażdżewski, 1993: 83. — De Broyer and Rauschert, 1999: 286. — Alonso de Pina, 2003a: 1052–1054 View Cited Treatment , figs. 13, 14. — Chiesa et al., 2005: 169–171, fig. 2C. — De Broyer et al., 2007: 187. — Chiesa and Alonso, 2007: 108. — Alonso de Pina et al., 2008: 9, 10, 33–35. — Alonso, 2012: 1883 View Cited Treatment . — Alonso and Chiesa, 2014: 206, 207, 209, fig. 2F–J.

Material examined. 1 female, dissected and illustrated, st. 2886, 38°06’S 55°13’W, Argentina, 440–480 m depth, February 1972 ( UERJ 470 ) GoogleMaps ; 2 females, in 70 % ethanol, same sampling data ( UERJ 471 ) ; 3 females, in 70 % ethanol, same sampling data ( MNRJ 29881 View Materials ) ; 3 females, in 70 % ethanol, same sampling data ( MZUSP 41266 View Materials ) ; 3 females, in 70 % ethanol, same sampling data (ColBIO BT 654 ) .

Diagnosis. Head with ovoid eyes. Antenna 2 peduncle article 4 with 3 facial rows of stout setae; article 5 facially with 1 medial stout seta and 1 distal one. Mandible incisors with 3 teeth, molar as small hump with 3 serrate stout setae, 1 being longer and thicker, accessory setal row with stout multicuspidate setae and short plumose setules between them, palpar hump small; palp article 1 weakly elongate, article 3 slightly longer than article 2. Maxilliped inner plate with 1 stout seta apically; outer plate with 1 apical cusp; palp article 4 narrow, bearing partially embedded medium apical nail. Gnathopods 1–2 palmar hump small. Gnathopod 2 carpus short. Epimeral plate 1 posteroventral corner subquadrate. Epimeral plate 2 with horizontal facial row of setae. Epimeral plate 3 ventral margin almost straight, posteroventral corner rounded. Uropod 1 peduncle with baso-facial setae, apico-lateral corner weakly combed. Uropod 2 apico-lateral corner weakly combed. Uropods 1–2 rami bearing embedded apical nail. Uropod 3 outer ramus with short article 2, bearing 2 setae apically. Telson apex subtruncate, with 1 plumose and 2 stout setae on each lobe.

Redescription (based on female, UERJ 470).Habitus as in Fig. 8 View Figure 8 . Head with medium-sized and ovoid eyes, rostrum not constricted. Antenna 1 peduncle article 1 ventral margin with long and brush setae distally, dorsal margin with setules proximally, dorsal apex produced with 2 setae; article 2 ventral margin with 7 long setae; article 3 ventral margin with 2 setae distally, with 4 facial brush setae; primary flagellum 9-articulate, with aesthetascs on articles 4–8; accessory f lagellum 7-articulate. Antenna 2 peduncle article 3 with 1 distal seta each dorsally and facially; article 4 facial stout setae formula: 3-4-2, ventral margin with 5 long pectinate setae and2 plumose setae proximally, dorsal margin with 2 sets of short to long setae, dorsal margin with 2 sets of setae (proximal, with two short simple and two long pectinate; distal, with one short simple, one short plumose and one long simple); article 5 ventral margin with 3 long pectinate and 3 brush setae distally; f lagellum 8-articulate. Upper lip and lower lip ordinary. Mandible incisor with 3 teeth (left and right); lacinia mobilis with 4 teeth (left) and multicupidate (right); molar as hump with 3 weakly serrate stout setae (left and right); accessory setal row with 10 (left) and 8 (right) multicuspidate stout setae; palp article 2 medial margin with 3 (left) and 4 (right) setae, article 3 apex oblique, with 9 (left) and 10 (right) medium to long pectinate setae. Maxilla 1 inner plate with 2 long and 2 short setae, medial and lateral margins setulose; outer plate with11 stout setae, being 9 multicuspidate; palp article 2 medial margin setulose, with row of 6 pectinate setae extending to apical margin and 4 pectinate setae subapically, setulose facially. Maxilla 2 inner plate subequal to outer, densely setulose medially and facially, apical, and subapical margins setose with medium to long plumose setae; outer plate medial margin setulose, apically with 6 long plumose setae, lateral margin setulose, with 4 stout pectinate setae distally. Maxilliped inner plate with 10 plumose setae; outer plate medial margin with 8 stout bipectinate setae and 6 setae, apical margin with 2 stout bipectinate setae, lateral margin with row of setules; palp article 2 medial margin moderately setose, lateral margin with 1 seta distally, article 3 medial margin moderately setose, with 5 facial setae, lateral margin with 2 setae medially and 3 distally, article 4 elongate, medial margin minutely combed, bearing 1 accessory seta.

Gnathopod 1 weak to moderately setose; coxa subrectangular, ventral margin with 14 setae; carpus about 0.7 × the length of propodus; propodus anterior margin with tuft of setae distally, posterior margin with 1 stout seta defining palm; dactylus reaching the palmar corner. Gnathopod 2 weak to moderately setose; coxa subrectangular, ventral margin with 12 setae; carpus anterior margin with 1 seta distally, posterior margin with 6 setae; propodus anterior margin with 3 setae and tuft of setae distally, posterior margin weakly setose, with 1 stout seta defining palm; dactylus reaching palmar corner, outer margin with 1 setule proximally. Pereopod 3 weak to moderately setose posteriorly; coxa subrectangular, ventral margin with 13 setae; carpus posterior margin moderately setose, distally with 1 long stout seta with accessory setule extending about 75 % length of propodus, with facial row of 6 setae; propodus posterior margin with 5 slender setae extending to apex; dactylus about 55 % length of propodus, outer margin with 1 short plumose seta. Pereopod 4 similar to pereopod 3, weak to moderately setose posteriorly; coxa produced posteriorly, excavate posterodorsally, posteroventral margin with 11 setae; merus longer and less stout than in pereopod 3. Pereopod 5 coxa bilobate, posteroventral margin with 3 pappose setae; basis 2.5 × longer than wide, anterior margin moderately setose, anterodistal corner with 6 setae; merus moderately setose, with stout setae distally; carpus and propodus moderately setose, with stout setae medially and distally, bearing pappose setae anteriorly and plumose setae posteriorly; dactylus about 50 % length of propodus, outer margin with 1 plumose seta. Pereopod 6 coxa posteroventral margin with 1 seta; basis 1.2 × longer than wide, anterior margin moderately setose; merus, carpus, propodus weakly setose, with sparse sets of stout setae mainly on anterior margin; dactylus about 40 % length of propodus, outer margin with 1 plumose seta proximally. Pereopod 7 coxa subtriangular, posterior margin with 4 setae; basis 1.3 × longer than wide, expanded posteroventrally, reaching half of carpus, anterodistal corner with 4 setae, posterior margin crenulate; merus, carpus, and propodus weak to moderately setose, with slender and sparse stout setae; dactylus about 60 % length of propodus, outer margin with 1 plumose seta proximally.

Epimeral plate 1 anterior margin with row of setae extending to anteroventral corner, ventral margin with 4 long plumose setae. Epimeral plate 2 anterior margin weakly concave, with 7 facial plumose setae, posterior margin weakly concave, with 4 short setae. Epimeral plate 3 anterior margin convex, ventral margin with 2 setae, posterior margin with 2 short setae. Uropod 1 peduncle with 10 basofacial setae, dorsomedial margin with 6 stout setae, dorsolateral margin with 3 setae distally, apico-lateral corner weakly combed; outer ramus slightly longer than inner, dorsal margin with 2 stout setae; inner ramus dorsal margin with 2 stout setae, ventrolateral margin with 1 thin seta. Uropod 2 peduncle dorsomedial margin with 13 stout setae, margins dorso-apical and ventro-apical weakly combed; rami naked; outer ramus 1.2 × longer than inner. Uropod 3 peduncle dorsomedial margin with 1 stout seta, apically with row of 8 stout setae; outer ramus 1.2 × longer than inner, article 1 ventrolateral margin with 5 stout setae, dorsolateral margin with 2 plumose setae distally, article 2 short, with 2 long plumose setae apically; inner ramus dorsomedial margin with 7 long plumose setae, apically with 2 long plumose setae. Telson about 80 % cleft, each lobe with 1 plumose and 2 stout setae.

Type locality. Chile, Magellanic region (54°08’S

71°01’W).

Remarks. Over time, F. fuegiensis has been allocated in three distinct genera; however, the species was not fully diagnosed, as we do here, and the appendages were lacking full illustrations and descriptions. Alonso de Pina (2003a) reported the possibility to observe certain variations among individuals of this species, mainly regarding the number of thin and stout setae on mouthparts and appendages. These variations were also found in the analyzed material, especially on the formula of facial setae present on the article 4 of antenna 2. They appear to be lower in number in smaller specimens and more numerous in larger ones, which can be related to the maturity of each individual. The material analyzed here shows 3-4-2 as the most common facial stout setal formula on the fourth article of antenna 2, while the original work by Barnard and Barnard (1980) shows 3-3-2. Additionally, Alonso de Pina (2003a) reported three different patterns in Argentina: 3-4-3 and 3-4-1 for specimens collected at Golfo Nuevo; and 3-3-3 for individuals from Golfo San José.

Chiesa and A lonso (2011) proposed an identification key to world species of Fuegiphoxus using a variable character as a diagnostic one (facial setal formula on article of antenna 2). Thus, we recommend disregarding this character in the third step of the key, and still consider the other ones, and the key will work properly for future identifications.

Geographic distribution. The species is well represented in southern South America, ranging from southern Uruguay (Atlantic coast), through the Beagle Channel, to Valparaiso, Chile (Pacific coast) ( Alonso, 2012). Also, there are records of F. fuegiensis from South Shetland Islands ( Antarctica), Tristan da Cunha and South Georgia Islands ( Alonso de Pina et al., 2008).