Fuegiphoxus abjectus Barnard and Barnard,

Fuegiphoxus abjectus Barnard and Barnard,

1980

( Figs. 3–7 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 )

Parharpinia fuegiensis View in CoL . — Schellenberg, 1931: 78.

Paraphoxus fuegiensis . — J.L. Barnard, 1960: 273.

Fuegiphoxus abjectus Barnard and Barnard, 1980: 862 View in CoL , figs. 5, 6. — Barnard and Barnard, 1990: 50. — Barnard and Karaman, 1991: 610. — González, 1991: 61. — De Broyer and Jażdżewski, 1993: 83. — Rothman, 1993: 751. — De Broyer and Rauschert, 1999: 286. — De Broyer et al., 2007: 187. — Chiesa and Alonso, 2007: 108. — Alonso de Pina et al., 2008: 8. — Chiesa and Alonso, 2011: 220, 221, 230, 231. — Andrade and Senna, 2020b: 156, 158.

Material examined. 1 female, dissected and illustrated, st. 2886, 38°06’S 55°13’W, Argentina, 440–480 m depth, February 1972 ( UERJ 468 ) GoogleMaps ; 1 female, in 70 % ethanol, same sampling data ( MNRJ 29880 View Materials ) .

Diagnosis. Head with eyes present in males and absent in females. Antenna 1, peduncle article 1 dorsal apex weakly to moderately produced. Antenna 2, peduncle article 4 with 3 facial rows of stout setae. Mandible incisor with 3 or 4 teeth, molar as small hump with 3 serrate stout setae, being 1 longer and thicker, accessory setal row with stout multicuspidate setae and short plumose setules between them, palpar hump small; palp article 3 longer than article 2. Maxilliped inner plate with 1 stout seta apically; outer plate with 2 apical cusps; palp article 4 narrow, bearing partially embedded medium apical nail. Gnathopods 1–2 palmar hump small.Gnathopod 2 carpus elongate. Pereopod 6 basis stout, anterior margin convex and produced, posterodistal lobe produced. Epimeral plate 1 anterior and posterior margins with row of setae, posteroventral corner quadrate to subquadrate. Epimeral plate 2with facial row of setae, posteroventral corner subquadrate. Epimeral plate 3 ventral margin almost straight, posteroventral corner rounded, posterior margin weakly convex. Uropod 1 peduncle with basofacial and ventral setae. Uropods 1–2 rami bearing embedded apical nail. Telson apex rounded apically, with small acclivity with 1 plumose and 2 stout setae on each side.

Redescription (based on female, UERJ 468). Habitus as in Fig. 3 View Figure 3 . Head without eyes; ventrolateral line present. Antenna 1 peduncle article 1 with distal brush setae ventrally and facially, dorsal apex with two setae; article 2 ventral margin with six bipectinate long setae, facially with four brush and two long bipectinate setae; article 3 ventral and dorsal margins with two setae each; primary flagellum 12-articulate; accessory f lagellum 9-articulate. Antenna 2 peduncle article 3 with one facial pectinate seta; article four facial stout setae formula: 3-4-4, ventral margin moderately setose; article 5 ventral margin moderately setose, facially with one stout and one plumose medial seta plus one stout seta distally; flagellum 11-articulate. Upper lip ordinary. Lower lip inner and outer lobes covered with setules apically. Mandible incisor with 3 (left) and 4 (right) teeth; lacinia mobilis flabellate with 4 teeth (left) and multicuspidate with large tooth (right); molar as hump with three serrate stout setae (left and right); accessory setal row with eight (left) and 10 (right) stout multicuspidate setae; palp article 2 medial margin with four (left) and five (right) setae, article 3 apex oblique, with seven (left) and eight (right) medium to long setae. Maxilla 1 inner plate with four setae, one being longer and plumose, lateral margin with setules; outer plate with 10 stout setae, nine being multicuspidate; palp article 2 setulose medially and facially, with five stout setae apically and four slender setae subapically. Maxilla 2 inner plate subequal to outer, medial margin densely setulose, with six plumose setae apically and seven slender setae subapically; outer plate setose apically, lateral margin covered with setules. Maxilliped inner plate with seven plumose setae, lateral margin with setules; outer plate medial margin with eight stout blunt setae bearing setules apically, apical margin with two stout blunt setae bearing setules apically, lateral margin setulose, with two apico-lateral pappose setae; palp article 1 with one seta apico-laterally, article 2 medial margin weakly setose, lateral margin with two setae apico-laterally, article 3 margins weakly setose, article 4 with one accessory seta.

Gnathopod 1 weak to moderately setose; coxa subrectangular, ventral margin with 19 long setae; carpus subequal to propodus in length; propodus anterior margin with tuft of setae distally, posterior margin with 1 stout seta defining palm; dactylus slightly longer than palm, outer margin with 1 leafshaped seta distally. Gnathopod 2 weak to moderately setose; coxa subrectangular, ventral margin with 15 long setae; carpus about 0.8 × the length of propodus; propodus anterior margin with tuft of setae distally, with 1 stout seta defining palm; dactylus reaching the palmar corner. Pereopod 3 weak to moderately setose posteriorly; coxa subrectangular, ventral margin with 14 setae; carpus posterior margin setose, distally with 1 long stout seta with accessory setule almost reaching apex of propodus, with 4 facial setae; propodus posterior margin with 10 slender setae extending to facial apex; dactylus about 40 % length of propodus. Pereopod 4 similar to pereopod 3, weak to moderately setose posteriorly; coxa produced posteriorly, excavate posterodorsally, posteroventral margin with 11 setae. Pereopod 5 coxa bilobate, posteroventral margin with 6 pappose setae; basis 1.8 × longer than wide, anterior margin with 4 setae proximally and 3 medially, anterodistal corner with 8 setae; ischium short and subrectangular, anterodistal corner with row of 8setae; merus, carpus and propodus setose, bearing plumose setae anteriorly and pappose setae posteriorly, with sets of distal stout setae; dactylus about 50 % length of propodus. Pereopod 6 coxa ovoid, anteroventral margin with 4 setae, ventral margin with small acute projection, posteroventral margin with 4 plumose setae; basis stout, slightly wider than long, anterior margin with short to long setae, medially and distally with 2 stout setae and row of long plumose setae; ischium anterodistal margin with 4 setae, posterior margin with setules; merus, carpus and propodus weak to moderately setose, bearing slender setae and sets of stout setae, mostly on anterior margin; dactylus about 40 % length of propodus. Pereopod 7 moderately setose anteriorly; coxa subtriangular, posterior margin with 1 short plumose seta; basis slightly longer than wide, expanded posteroventrally, reaching apex of merus, anterior margin with setae proximally and medially, anterodistal corner with row of 5 plumose setae, posterior margin weakly crenulate; ischium with distofacial lobe produced; merus anterior margin setose with plumose setae, posterior margin with 1 seta distally; carpus and propodus moderately setose; dactylus about half length of propodus, outer margin with 1 short plumose setae.

Epimeral plate 1 anterior and posterior margins with row of 16 plumose setae, posteroventral corner subquadrate. Epimeral plate 2 anteroventral corner rounded, with9 facial plumose setae, posterior margin weakly concave. Epimeral plate 3 anterior margin concave, anteroventral corner rounded, ventral margin with 4 setae, posterior margin weakly convex, with 2 tiny notches bearing 1 setule each. Uropod 1 peduncle with 3 basofacial setae, dorsomedial margin with 7 stout setae, ventral margin with 3 setae proximally; outer ramus slightly longer than inner, naked; inner ramus dorsomedial margin with 2 stout setae, ventrolateral margin with 1 thin seta. Uropod 2 peduncle dorsolateral margin with 9 stout setae, with weak comb distally; outer ramus slightly shorter than inner, dorsal margin with 1 stout seta; inner ramus naked. Uropod 3 peduncle dorso-apical corner with 1 stout seta, ventro-apical corner with 4 stout setae; outer ramus 1.2 × longer than inner, article 1 ventrolateral margin with 1 thin and 4 stout setae, dorsolateral margin with 4 setae, article 2 with 2 setae apically; inner ramus with 3 setae apically. Telson about 85 % cleft, each lobe with 1 plumose and 2 stout setae.

Type locality. Chile, Bahía Inutil (53°30’S 69°45’W) GoogleMaps .

Remarks. The species was originally described by Schellenberg (1931) assigned to Parharpinia Stebbing, 1899 based on material collected at the Magellanic region and surroundings. J.L. Barnard (1960) reexamined the type material and defined one individual as a female of Pa. fuegiensis . After a thorough character analysis, Barnard and Barnard (1980) found that the Pa. fuegiensis original material was mixed with two undescribed species and between them, described F. abjectus based on a male specimen.

Barnard and Barnard (1980) state that the eyes of their specimen could be small, absent or diffuse. This character can be difficult to observe in some species due to the loss of pigmentation of the eyes after storage in collections. However, the presence of the male’s eyes is clear on J.L. Barnard (1960); also, he cites an aberrant female specimen found with no eyes and presenting a very stout and modified antennae, resembling a Lysianassidae Dana, 1849 . The author’s illustrations are not enough to make a detailed comparison with our samples, but the absence of eyes and shape of gnathopod 1 are confirmed, even if the stoutness of the first antenna is rejected. Although there are no more detailed descriptions of F. abjectus females, herein we present the first full description and illustrations of a female. Besides some common variations, such as number and length of setae on the appendages, a diagnosis for the species is provided in agreement with the literature.

The individuals studied here agree with the original description of F. abjectus , although they present some significant morphological differences, as follows (characters of type material in parentheses): antenna 2 article 4 facial stout setae formula as 3-4-4 (vs 3-3-3- 1); pereopods 3–4 propodus without distal clump of setae (vs propodus with distal setal clump); pereopod 7 propodus distally smooth, without processes (vs combed, with nine digital processes); uropod 1 outer ramus naked (vs with three stout setae); uropod 2 inner ramus naked (vs with one stout seta).

Considering the newly observed characters, plus the ones pointed out by Barnard and Barnard (1980), F. abjectus can be distinguished from its congeners by the following: head without eyes in females; male antenna 1 with an unusual shape; facial stout setae arrangement on article 4 of antenna 2; mandible right incisor with four teeth; maxilliped outer plate with two apical cusps; gnathopod 2 weakly enlarged, carpus elongated; pereopod 5 with narrower basis; pereopod 6 basis anterior margin broadly convex, posterodistal lobe produced; epimeral plate 3 posterior margin weakly convex, with two notches bearing one setule each. In addition, characters observed in this study, such as the absence of eyes in females, the right mandible incisor with four teeth and a multicuspidate lacinia mobilis were significant to provide an amended diagnosis for the genus.

This is the first record of the species for Argentine waters ( Fig. 25 View Figure 25 ).

Geographic distribution. Chile: Bahía Inutil (53°30’S 69°45’W) GoogleMaps . Argentina: off northern Buenos Aires Province (38°06’S 55°13’W) GoogleMaps .

Bathymetric range. The species was previously reported from 36–55 meters depth. In the record presented herein, F.abjectus was collected at 440–480 meters depth, extending its distribution to a wider bathymetric range.