Labriphimedia vespuccii K.H. Barnard, 1931

Coleman, Charles Oliver, Krapp-Schickel, Traudl & Häussermann, Vreni, 2022, Amphipod crustaceans from Chilean Patagonia, European Journal of Taxonomy 849 (1), pp. 1-57 : 29-36

Labriphimedia vespuccii K.H. Barnard, 1931

Figs 18–22

Labriphimedia vespuccii K.H. Barnard, 1931: 427 .

Labriphimedia vespuccii – K.H. Barnard 1932: 124, fig. 69. — J.L. Barnard 1958: 18. — Lowry & Bullock 1976: 15. — Watling & Thurston 1989: 311. — J.L. Barnard & Karaman 1991: 396. — De Broyer & Jażdżewski 1993: 57. — Coleman 2007: 111, fig. 71a–b, map 34 (circle). — De Broyer et al. 2007: 104.

Material examined

CHILE • 1 ♀ (21 mm) ( Figs 18–22 ), 4 juvs; Punta Garro ; -46.315167°, -73.652033°; 20 m depth; 30 Nov. 2011; HF11C355; rock, on gorgonian; ZMB 34096 • 1 unsexed spec.; Isla Jorge ; -44.861483°, -74.005400°; 18 m depth; 22 Nov. 2011; HF11C087; coarse sand with stones; ZMB 34095 .

Description (based on ovigerous ♀, 21 mm)

BODY ( Fig. 18a ). Head with small oval eyes; rostrum ( Fig. 18a, d ) moderately short and wide; frontal head margin sinuous. Pereonite 1 as long as pereonites 1 and 2 combined. Pereonites 4–6 subequal in length; posteroventral angle of tergites 5 and 6 angular and pointed respectively. Pereonite 7 with posteromarginal pair of pointed processes, space between paired dorsal processes strongly narrowed at the segmental border and v-shaped; posteroventral angle pointed and drawn out. Pleonite 1 with subequal posteromarginal paired processes as on pereonite 7; posterior margin with small point; epimeral plate rounded ventrally. Pleonite 2 with subequal posteromarginal paired processes as on pereonite 7, middorsal crest and shallow hump, seen from lateral side; posteromarginal lateral margin with small point; posteroventral corner acutely drawn out, dorsally of the process margin somewhat serrate. Pleonite 3 with two shorter posteromarginal paired processes and between these a short carina; posterior lateral margin of epimeral plate 3 with pointed process and ventrally of that serrate, posteroventral corner with pointed with process, about the size of that on epimeral plate 2. Urosomite 1 longest, with a notch seen from laterally. Urosomite 2 shortest. Urosomite 3 twice the length of urosomite 2.

HEAD APPENDAGES. Antenna 1 ( Fig. 18b, d ) peduncular article 1 massive, 1.5 × as long as wide, subrectangular and distally straight except for two subacute lobe; peduncular article 2 about half the length of article 1 (57%), with two apical pointed drawn out equally long processes, not exceeding beyond distal margin of article 3; article 3 subrectangular, with inconspicuous, scale-like vestige of an accessory flagellum; primary flagellum first article longer than next two articles, number of flagellum articles unknown (broken off at the tip). Antenna 2 ( Fig. 19e ) peduncular article 4 1.5 × as long as article 3, with 2 pointed processes; peduncular article 5 slightly longer than 4, distally straight; flagellum article 1 about as long as the following 3 articles combined; number of flagellum articles unknown (broken off at the tip). Upper lip (labrum) entire, with fields of hair-like setae on both sides of the apex. Mandible ( Fig. 18c, e–f ) tapering distally, incisor without dentation, rounded, medially excavate; no lacinia mobilis on both sides; molar vestigial, rounded lobe without triturative surface; palp article ratios (from article 1 to 3) 1:1.6:1:4; article 1 without setation, article 2 with a group of distomedial setae; article 3 lanceolate with a row of plumose setae mediomarginally, inner surface covered by hair-like setae. Lower lip (hypopharynx) with wide lobes and rather narrow lateral lobes. Maxilla 1 ( Fig. 19a ) inner lobe tapering distally, with 8 plumose setae on the mediodistal margin; outer plate with 11 in part serrate spine-like setae distomarginally; palp biarticulate, longer than outer plate, article 2 1.9× the length of article 1, tapering distally, with 6 terminal setae. Maxilla 2 ( Fig. 19b ) inner plate slightly shorter than outer plate, 1.4× as wide as outer plate; two rows of setae (see detail drawing) apically. Maxilliped ( Fig. 19d ) inner plates ( Fig. 19c ) subrectangular, outer margins slightly convex, with medial row of long setae mediomarginally, apical margin with shorter setae; outer plate ( Fig. 20a ) tapering distally with dense setation apicomedially and apicolaterally, apex almost reaching distal margin of palp article 2; palp ( Fig. 20b ) with 3 long articles and 1 minute article inserted subapically on article 3, length ratios of article 1–4 1:0.7:0.7: 0.09, article 2 not produced forward and not guarding along inside article 3.

PEREON. Gnathopod 1 ( Fig. 20c, e ) coxa ventrally rounded; basis about as long as merus to dactylus combined, with row of setae anteromarginally, posterior margin convex, anterior margin sinuous; ischium subrectangular, 1.6× as long as wide; merus tapering distally into a point, about as long as propodus; carpus attached along the medial side of merus, slightly longer than propodus; propodus with several setae distally forming a chela with finger-like dactylus. Gnathopod 2 ( Figs 20d , 21a ) coxa tapering distally with serrate apex; basis subrectangular with oblique distal margin; ischium subequal in length to merus; carpus slightly expanded distally and with posteromarginal groups of setae; propodus longer than carpus with groups of setae on both margins, posterodistal lobe and dactylus form a chela. Pereopod 3 ( Fig. 21d ) coxa anterior margin convex, posterior margin straight, apex rounded with some small teeth posterodistally; basis subrectangular, laterally with a semicircular lobe in the middle of the distal margin; ischium longer than wide, with similar lobe in the middle of distal margin; merus expanded distally somewhat drawn out antero- and posterodistally, with some robust setae; carpus weakly expanded with shallow lobe on medial side, with groups of robust setae on posterior margin, posterodistal angle and anterodistal margin; propodus subrectangular with groups of robust setae posteromarginally; dactylus weakly curved; length ratios ischium to dactylus: 1: 1.5: 1.3: 2.5:1.2. Pereopod 4 ( Fig. 21c ) coxa anteriorly strongly convex, posteroventrally rectangular, posterior margin with narrow rounded lobe in the middle; basis half as long as coxa, subrectangular with rounded lobe in the middle of distal margin; ischium longer than wide with similar lobe as basis; merus to dactylus subequal to that of pereopod 3. Pereopod 5 ( Fig. 22a ) coxa bilobed, anterior lobe semicircular, posterior lobe subangular posteromarginally; basis slightly longer than wide (1.2×), anterior margin with groups of robust setae, anterodistal angle acutely drawn out, ventrally rounded, not surpassing distal margin of ischium, posterior margin drawn out, truncate to slightly excavate with serrate margin on proximal ⅔; ischium wider than long, with acutely drawn out anterodistal corner; merus distally expanded, posterodistally strongly produced into a pointed lobe, anterodistally with short point; carpus and propodus subrectangular; dactylus stout and rather short; length ratios merus to dactylus: 1:0.9:1.5: 0.39. Pereopod 6 ( Fig. 22c ) coxa bilobed, equally long, anterior lobe rounded, posterior lobe drawn out posteriorly into a pointed tip, posteroventral margin weakly serrate; basis about as wide as long, ventrally not surpassing distal margin of ischium, anterior margin lined with robust setae, anteroventral angle pointed and produced, posterior and posteroventral margin serrate, drawn out tooth on ventral third of posterior margin; ischium wider than long, excluded pointed lobe anteroventrally; merus distally expanded, with groups of robust setae anteromarginally, posterodistally acutely drawn out, short process anterodistally. Pereopod 7 ( Fig. 22b ) coxa ventrally rounded and weakly serrate, posteriorly pointed; basis convex anteromarginally with robust setae, anterodistally acutely drawn out, posteromarginally sinuous and serrate, with truncate posterior margin, drawn out tooth posteroventrally, basis surpassing distal margin of ischium; ischium longer than wide, with small pointed anterodistal tooth; merus distally widened and acutely drawn out posterodistally, anterior margin with groups of robust setae and shorter setae posteromarginally; carpus weakly expanded distally and with anteromarginal groups of robust setae; propodus longer than carpus; length ratios ischium to dactylus: 1: 2,5: 2.4: 3: 1.2.

U ROSOME. Uropod 1 ( Fig. 21b ) peduncle longer than rami, with robust setae on both margins; rami slender and subequal. Uropod 2 ( Fig. 22d ) peduncle outer margin with some robust setae; outer ramus slightly shorter than peduncle, outer ramus 0.67 × the length of the inner ramus. Uropod 3 ( Fig. 22e ) inner ramus 3× the length of the peduncle. Telson ( Fig. 21e ) 1.4× as long as wide, roundly notched apically (27 % depth), lobes pointed; dorsal face with 2 lateral groups of 3 plumose sensory setae.

Distribution

Falkland Islands: Discovery 1925–27, stn 51, off Eddystone Rock, 105–115 m (bottom/habitat: fine sand; gear: large heavy dredge, large otter trawl, nets) (K.H. Barnard 1932).

Magellan Province: Isla Jorge; Punta Garro, 18–20 m (this study).

Depth range

18– 115 m.

Type locality

Discovery 1925–27, stn 51, off Eddystone Rock, 105–115 m (K.H. Barnard 1932).

Type specimen location

The Natural History Museum, London.

Remarks

This is the first full description of this species since the original description and some illustrations given one year later by K.H. Barnard (1931, 1932). The original material had been collected off the Falkland Islands. Between K.H. Barnard’s descriptions and the Magellan material, redescribed herein, there are a few minor differences:(1) dorsal paired teeth on pleon shorter than described in the holotype; (2) middorsal tooth on pleonite 3 shorter; (3) traces of serration on epimeral plate 2 (vs smooth); (4) urosomite 1 with middorsal angular process (vs pointed tooth) and no posteromarginal carina (vs pointed tooth).

Figures

Fig. 18. Labriphimedia vespuccii K.H. Barnard, 1931, ♀, 21 mm (ZMB 34096). a. Habitus, left body side. b. Antenna 1. c. Left mandible. d. Head, frontal aspect. e. Mandible palp. f. Right mandible. Scale bars: a = 1 mm; b–c, f = 200 µm; e = 100 µm.

Fig. 19. Labriphimedia vespuccii K.H. Barnard, 1931, ♀, 21 mm (ZMB 34096). a. Maxilla 1.b. Maxilla 2. c. Inner plate of maxilliped. d. Outlines of maxilliped, setae omitted. e. Antenna 2. Scale bars: a–c = 100 µm; d = 1 mm; e = 200 µm.

Fig. 20. Labriphimedia vespuccii K.H. Barnard, 1931, ♀, 21 mm (ZMB 34096). a. Outer plate of maxilliped. b. Palp of maxilliped. c. Gnathopod 1. d. Gnathopod 2, setae on propodus omitted. e. Chela of gnathopod 1. Scale bars: a–b, e = 100 µm; c = 200 µm; d = 1 mm.

Fig. 21. Labriphimedia vespuccii K.H. Barnard, 1931, ♀, 21 mm (ZMB 34096). a. Propodus of gnathopod 2, dactylus damaged. b. Uropod 1. c. Pereopod 4. d. Pereopod 3. e. Telson. Scale bars: a = 200 µm; b–d = 1 mm; e = 200 µm.

Fig. 22. Labriphimedia vespuccii K.H. Barnard, 1931, ♀, 21 mm (ZMB 34096). a. Pereopod 5. b. Pereopod 7. c. Pereopod 6. d. Uropod 2. e. Uropod 3. Scale bars = 1 mm.