Valettiopsis longidactyla, Horton, 2004

Horton, Tammy, 2004, Revision of the amphipod genus Valettiopsis Holmes, 1908 (Crustacea: Lysianassoidea), with the addition of three new species, Journal of Natural History 38 (14), pp. 1735-1755 : 1739-1748

Valettiopsis longidactyla sp. nov.

( figures 3–5 )

Type material. Holotype: dissected male specimen and slide series, NHM reg. no. 2003.96; paratype: male, NHM reg. no. 2003.97.

Type locality. Off Angolan coast, baited traps attached to BP ROBIO lander; BP/ Gardline Angola Cruise 5765, February 2002 (Station 500; 7 ‡ 44 ’ 53 @ S, 11 ‡ 58 ’ 10 @ E; 1252 m) .

Material examined. Holotype male, 16.9 mm, paratype male, 15.7 mm.

Description. Holotype, male, 16.9 mm. Head and body: preserved colour translucent grey, without setae. Head: exposed, deeper than long, lateral cephalic lobe broadly rounded ventrally with shallow excavation for antenna 2. Pereonites

and pleonites dorsally smooth. Urosomites: 1–3 free; urosomite 1 produced into prominent dorsal tooth, apex acute.

Antenna 1: medium length; peduncle article 1 as long as wide; anterodistal lobe reaching halfway along article 2; article 2 short (0.3 6 length of article 1); article 3 short (0.2 6 length of article 1); flagellum 28-articulate; callynophore strong, setae present on flagellar articles; accessory flagellum well developed, with eight or nine articles, short (0.3 6 primary flagellum); article 1 at least twice as long as article 2.

Antenna 2: slightly longer than antenna 1; peduncle articles 4 and 5 with strong brush setae on anterior margin; article 3 short (0.3 6 length of article 4); article 4 enlarged; article 5 subequal in length to article 4 but more slender; well-developed flagellum, with 32 articles.

Mouthparts: forming subquadrate bundle. Upper lip: rounded with minute

apical notch. Lower lip: outer lobes elongate, robustly spinulose on inner distal margin.

Mandible: incisor robustly six-dentate, lacinia mobilis four-dentate; 11 cuspidate accessory setae, interspersed with long pappose intermediate setae. Molar with

strong triturating surface, large plumose seta present (not visible on illustration). Palp attached distally, article 1 short, without setae; article 2 elongate, broadened medially/centrally; three A2 setae present, D2 setae present along distal half, B2 setae present proximally on medial posterior margin. Article 3 long, slender oval; three A3 setae, three B3 setae and six E3 setae present, 24 D3 setae on the posterodistal two-thirds of the margin.

Maxilla 1: inner plate tapering distally, inner margin fully setose. Outer plate, setal teeth in 7:4 arrangement. Outer row: ST1–3 large, stout, without cusps; ST4–5 large, slender, with cusps; ST6 small, slender, cuspidate and slightly displaced from ST5; ST7 small, slender, curved and slightly displaced from ST6. Inner row: STA–B large slender, three-cuspidate; STC large, slender, five-cuspidate, displaced from STB; STD large, slender, four-cuspidate, displaced from STC. Palp: twoarticulate with 10 terminal conical teeth and five terminal robust setae; 10 subterminal setae; article 2 with medial lateral robust seta; article 1 with two long submarginal lateral robust setae.

Maxilla 2: inner and outer plates narrow, subequal in length. Outer plate, setae distally cuspidate. Inner plate, with a row of pappose facial setae, a row of cuspidate marginal setae and a row of simple plumose setae.

Maxilliped: inner plate subrectangular, 0.5 6 outer plate, with 12 long apical setae; two distal nodular setae on apical face near inner margin; oblique setal row reduced, with five long plumose setae. Outer plate small, reaching halfway along palp article 2, subovate, medial margin finely setose; 27 short robust setae proximally on the inner margin, grading to 13 elongate plumose setae distally; submarginal inner face with horizontal rows of two to three short fine setae. Palp large, elongate and four-articulate; inner margin of article 2 with distal row of long setae and six proximal horizontal rows of two or three setae; article 3, with row of 10 strong facial setae and four groups of medial lateral setae; dactylus well developed with one subterminal robust seta and one fine seta. Each article of the palp with outer apical margin bearing long setae.

Coxae 1–3 with setal fringe along ventrolateral margin.

Gnathopod 1: subchelate, sexual dimorphism unknown; coxa 1 reduced, subtriangular, 0.75 6 length of coxa 2, tapering distally with small indented seta and groups of setae on distal lateral margin; basis long (length 3.6 6 breadth); ischium short (length 1.5 6 breadth); merus short (length 1.7 6 breadth) with patch of short setules on posterior margin; carpus long (length 2.25 6 breadth) subtriangular, posterior margin with long setae and mat of short setules; propodus large, subrectangular (length 2.5 6 breadth), margins converging slightly distally, subequal in length to carpus, posterior margin smooth, straight, with six groups of simple slender setae; five groups of distomedial setae; palm slightly obtuse, straight, lined with a row of short setae and with two long robust setae on the posterodistal corner; dactylus simple with three long medial setae and one fine setule along posterior margin.

Gnathopod 2: subchelate; coxa large, subequal to coxa 3, with small indented seta and groups of setae on distal lateral margin; basis long (length 4.4 6 breadth); ischium long (length 4 6 breadth); merus long (length 4 6 breadth); carpus subtriangular, elongate (length 5.3 6 breadth), longer than propodus, with seven groups of long simple setae; propodus long, subrectangular (length 4 6 breadth) with seven groups of long simple setae on posterior margin, posterodistal margin with a row of six robust setae decreasing in size; palm obtuse, straight, lined with a row of eight short setae and with four long simple setae proximal to the dactylus; dactylus long, just overlapping palmar angle, posterior margin smooth with one seta proximal to propodus and two medial facial setae, one long and one short.

Pereopod 3: simple; coxa large, subrectangular; posterodistal angle with rows of pairs of setae; propodus subequal in length to carpus with nine robust setae in six groups along posterior margin; dactylus long, slender, slightly curved with one seta on posterior margin.

Pereopod 4: simple; coxa deeper than wide, large posteroventral lobe with both anterior and posterior margins rounded; propodus with six groups of robust setae along posterior margin; dactylus long, slender, slightly curved with a fine seta on anterior margin and one fine seta subapically.

Pereopod 5: coxa bilobate, smooth posterior margin with four robust setae; basis expanded, posterior margin gently convex, minutely crenate, posterodistal lobe extended halfway down ischium (when pereopod is straight); propodus with robust setae in three groups along anterior margin; dactyl very long, slender, straight with one fine seta on smooth posterior margin.

Pereopod 6: as pereopod 5 but longer, coxa weakly bilobate and posteroventral lobe of basis reaching two-thirds down ischium (when pereopod is straight).

Pereopod 7: as pereopod 6 but with coxa reduced rather than bilobate, basis posterior margin evenly rounded, posteroventral lobe subacute, as long as ischium.

Epimeron 1 anteroventral corner rounded; epimeron 3 posteroventral corner produced into an acute tooth.

Uropod 1: biramous, inner and outer rami subequal, with both margins lined with short robust setae; peduncle with row of short and long setae on inner margin, and long robust setae on outer margin; one large robust seta present on peduncle at base of outer ramus.

Uropod 2: biramous (inner ramus damaged) shorter than uropod 1 and with fewer peduncle setae.

Uropod 3: biramous, well developed, peduncle long (length 1.5 6 breadth), with apicolateral robust setae; rami lanceolate, subequal in length, with lateral and medial rows of short robust setae; outer ramus two-articulate, article 2 short; inner edge of inner ramus with slender plumose setae.

Telson: cleft for 80% of length, four long robust setae dorsally on each lobe; outer margins with three, and six robust setae laterally on left and right lobes, respectively; distal margin with three to four graduated robust setae; inner distal margin produced into acute apex; outer distal margin concave.

Remarks. This species is described from two adult male specimens. It differs from other members of the genus in having an elongate, slender carpus of gnathopod 2 combined with long slender, straight dactyls on pereopods 3–7.

Etymology. This species is named in reference to its characteristic elongate, straight dactyls on pereopods 3–7.

Valettiopsis macrodactyla Chevreux, 1909

( figures 6–8 )

Valettiopsis macrodactyla Chevreux, 1909: 1 , figures 1 , 2 ; 1935: 8, plate 2, figure 1 ; Barnard and Karaman, 1991: 540; Serejo and Wakabara, 2003. Not Valettiopsis macrodactyla (~ V. lincolni sp. nov.) Lincoln and Thurston, 1983: 87–89, figures 1–3 .

Type material. Holotype, female, 14 mm, Musée Océanographique de Monaco, reg. no. 37 0438. Station 723, contains 13 adult females (11.06–16.55 mm), 28 juveniles and dissected parts.

Type locality. Close to the Azores, Station 723 (38 ‡ 17 ’ 40 @ N, 28 ‡ 15 ’ 10 @ W, 1692 m), 31 July–1 August 1896.

Other material. Station 724, 38 ‡ 17 ’ 40 @ N, 28 ‡ 15 ’ 10 @ W, 1692 m; 31 July–1 August 1896, one adult male specimen, 14.51 mm, Musée Océanographique de Monaco, reg. no. 37 0438. Dissected parts from Station 738, 1919 m, Musée Océanographique de Monaco, reg. no. 37 0645 .

BP/Gardline Angola Cruise 5765, February 2002; baited traps attached to ROBIO lander: Station 500; 7 ‡ 44 ’ 53 @ S, 11 ‡ 58 ’ 10 @ E; 1252 m; one adult male specimen, 16 mm, NHM reg. no. 2003.98; Station 501; 7 ‡ 54 ’ 36 @ S, 12 ‡ 0 ’ 23 @ E; 1451 m; one immature female specimen, 16.7 mm (NHM reg. no. 2003.99) and six male specimens, 14.5–15.9 mm (NHM reg. no. 2003.100–105, and for the nine slides from this station, NHM reg. no. 2003.106); Station 502; 7 ‡ 55 ’ 2 @ S, 12 ‡ 4 ’ 5 @ E; 1477 m, one adult male specimen, 13.1 mm (NHM reg. no. 2003.107); Station 504; 7 ‡ 59 ’ 21 @ S, 12 ‡ 18 ’ 46 @ E; 1442 m; one immature female specimen (NHM reg. no. 2003.107).

TAAF MD 55 /Brazil, 1987, Marion Dufresne cruise, Station 59, 21 ‡ 36 ’ S, 39 ‡ 58 ’ W, 1190–1295 m, one adult female specimen, 19.8 mm, Museu Nacional, Rio de Janeiro reg. no. 15696 .

Description. Immature female, 16.7 mm, Station 501. Head and body: preserved colour tan, without setae. Head: exposed, deeper than long, lateral cephalic lobe with shallow excavation for antenna 2. Pereonites and pleonites dorsally smooth. Urosomites: 1–3 free; urosomite 1 produced into prominent dorsal tooth, anterior margin straight, apex acute.

Antenna 1: medium length; peduncle article 1 longer than wide; article 2 short (0.5 6 length of article 1); article 3 medium (0.23 6 length of article 1); flagellum with 27–29 articles; callynophore strong, setae and aesthetascs present on flagellar articles; accessory flagellum well developed, eight or nine articles, short (0.23 6 primary flagellum); article 1 subequal length to article 2.

Antenna 2: slightly longer than antenna 1 (illustrated specimen has broken antenna 2); peduncle with weak brush setae; article 3 short (0.2 6 length of article 4); article 5 subequal in length to article 4 but more slender; well-developed fla-

gellum with 35–37 articles.

Mouthparts: forming subquadrate bundle. Upper lip: rounded. Lower lip: outer lobes elongate, robustly spinulose on inner distal margin.

Mandible: incisor robustly seven-dentate, lacinia mobilis strongly eight-dentate; 10 distally dentate accessory setae, interspersed with long pappose intermediate setae. Molar with strong triturating surface, large plumose seta present. Palp attached level with molar, article 1 short, without setae; article 2 elongate, slightly broadened medially, 16 D2 setae present along distal third; article 3 oval; four A3 setae and five E3 setae present, 24 D3 setae on the posterodistal two-thirds of the margin.

Maxilla 1: inner plate tapering distally, inner margin fully setose. Outer plate setal teeth in 7:4 arrangement. Outer row: ST1–3 large, stout, with one or two cusps; ST4–5 large, slender, with cusps; ST6 small, slender, cuspidate and slightly displaced from ST5; ST7 small, slender, curved and slightly displaced from ST6. Inner row: STA large, slender, six-cuspidate; STB large, slender, eight-cuspidate; STC large, slender, seven-cuspidate, displaced from STB; STD large, slender, sevencuspidate, displaced from STC. Palp: two-articulate with 10 terminal conical teeth and one long robust seta; 10 subterminal setae; article 1 with one long submarginal lateral slender seta.

Maxilla 2: inner and outer plates narrow, subequal in length, densely setose; inner plate, with a row of pappose facial setae, a row of plumose marginal setae and a row of simple plumose setae.

Maxilliped: inner plate subrectangular, 0.5 6 outer plate, with 12 long apical setae, three distal nodular setae on apical face near inner margin; oblique setal row with eight long plumose setae. Outer plate small, reaching halfway along palp article 2, subovate, medial margin finely setose; 14 short robust setae proximally on the inner margin grading to seven elongate plumose robust setae distally; submarginal inner face with horizontal rows of two to three fine setae. Palp large, elongate and four-articulate; inner margin of article 2 with distal row of long setae and five proximal horizontal rows of setae; article 3, with row of eight strong facial setae and four medial lateral setae; dactylus well developed with one subterminal seta and one fine seta. Each article of the palp with outer apical margin bearing long setae.

Coxae 1–4 with setal fringe along ventrolateral margin.

Gnathopod 1: subchelate; coxa 1 reduced, subtriangular, 0.5 6 length of coxa 2, tapering distally with three setae on distal margin; basis long (length 4.2 6 breadth); ischium long (length 2 6 breadth); merus short (length 1.3 6 breadth) with patch of short setules on posterior margin; carpus long (length 2 6 breadth) subtriangular, posterior margin with long setae; propodus large, subrectangular (length 2.4 6 breadth), subequal in length to carpus, posterior margin smooth, straight, with five groups of simple slender setae; five groups of distomedial setae, four groups of setae on anterior margin; palm transverse, straight, lined with a row of short setae, three longer setae proximal to the dactylus and two long and two short robust setae on the posterodistal corner; dactylus simple with two long medial setae and one seta on posterior margin.

Gnathopod 2: subchelate; coxa large, subequal to coxa 3, setae on distal margin; basis long (length 4.2 6 breadth); ischium long (length 2.1 6 breadth); merus long (length 2.1 6 breadth); carpus subtriangular (length 2.1 6 breadth), subequal to propodus, with nine groups of long simple setae; propodus subrectangular, expanded (length 1.5 6 breadth) with 11 groups of long simple setae on posterior margin, palmar angle with a group of five robust setae; palm strongly concave, lined with a row of 12 short robust setae and with two long simple setae proximal to the dactylus; dactylus long, not reaching corner of palm, posterior margin smooth with two medial facial setae, one long and one short, and one seta on posterior margin.

Pereopod 3: simple; coxa large, subrectangular, ventral margin with row of short fine setae; propodus longer than carpus with four groups of robust setae and one robust seta (locking spine) along posterior margin; dactylus strongly curved.

Pereopod 4: simple; coxa deeper than wide, posteroventral lobe weak with both anterior and posterior margins rounded, ventral margin with row of short fine setae and three long setae; propodus longer than carpus with three groups of robust setae and one robust seta (locking spine) along posterior margin; dactylus strongly curved.

Pereopod 5: coxa equilobate, posterior margin smooth; basis weakly expanded (length 1.7 6 breadth), posterodistal margin weakly convex, minutely crenate; propodus with four groups of robust setae and two robust setae (locking spines) along anterior margin; dactyl curved.

Pereopod 6: as pereopod 5 but coxa bilobate, posterior lobe produced ventrally; basis weakly expanded, not tapering.

Pereopod 7: as pereopod 6 but with basis slightly broader.

Epimeron 1 anteroventral corner rounded with one or two setae; epimeron 2 with posteroventral corner produced into small spine, four to five setae on ventral margin; epimeron 3 posteroventral corner produced into an acute spine, eight to nine setae on ventral margin.

Uropod 1: biramous, inner and outer rami subequal with lateral rows of short robust setae; peduncle with rows of short robust setae on inner and outer margins; one large robust seta on peduncle at base of outer ramus.

Uropod 2: biramous, as uropod 1 but with fewer setae on peduncle.

Uropod 3: biramous, well developed, peduncle long (length 1.5 6 breadth), with apicolateral robust setae; rami lanceolate, subequal in length, with lateral and medial rows of short robust setae; medial margin of inner ramus with slender plumose setae; outer ramus two-articulate, article 2 short.

Telson: cleft for 73% of length; two robust setae on each lobe; apices of lobes notched, with two to three graduated robust setae.

Remarks. Valettiopsis macrodactyla was first described by Chevreux, 1909 and the description repeated (but with different illustrations and further material) in 1935. A further specimen was attributed to V. macrodactyla by Lincoln and Thurston (1983). However, a comparison of this specimen with new material collected from Angolan waters, and confirmation of some of the measurements and characters from the type material held at the Musée Océanographique de Monaco, show that the description of Lincoln and Thurston (1983) is not of V. macrodactyla . It is recognized here as V. lincolni sp. nov. An error in Chevreux (1909) and repeated in Chevreux (1935) states that the length of the holotype of V. macrodactyla is 4 mm. This should read 14 mm.

Figures

FIG. 3. Valettiopsis longidactyla, sp. nov., holotype, 16.9 mm male.

FIG. 4. Valettiopsis longidactyla, sp. nov., holotype, 16.9 mm male.

FIG. 5. Valettiopsis longidactyla, sp. nov., holotype, 16.9 mm male.

FIG. 6. Valettiopsis macrodactyla, adult male, 16 mm.

FIG. 7. Valettiopsis macrodactyla, adult male, 16 mm.

FIG. 8. Valettiopsis macrodactyla, adult male, 16 mm.

FIG. 1. Valettiopsis dentata, gnathopods 1–2. Holotype, 6mm male.

FIG. 2. Valettiopsis lincolni, gnathopods 1–2. Holotype, 17 mm male.