Fuegiphoxus fuegiensis (Schellenberg)

ALONSO DE PINA, GLORIA M., 2003, A new species of Phoxocephalidae and some other records of sand-burrowing Amphipoda (Crustacea) from Argentina, Journal of Natural History 37 (9), pp. 1029-1057 : 1052-1054

Fuegiphoxus fuegiensis (Schellenberg)

( figures 13 , 14 ) Parharpinia fuegiensis Schellenberg, 1931: 78–80 , figure 40. Paraphoxus fuegiensis: Barnard, 1960: 271 , 272, pl. 42. Fuegiphoxus fuegiensis: Barnard and Barnard, 1980: 853–858 , figures 1–3 .

Material examined

Chubut: Golfo Nuevo, Bahía Nueva, Golfito beach (approx. 42 ° 46 ∞ S, 65 ° 02 ∞ W), 8–10 m depth, 6 August 1992, one ♀ dissected approx. 7.5 mm, MACN No. 34686; one 3 dissected 6.5 mm, MACN No. 34687; three ♀♀ 5.75–6.20 mm, MACN No. 34688. Collector and donor: G. Pagnoni. Golfo San José (42 ° 20 ∞ S, 64 ° 20 ∞ W), 80 m depth, 7 September 1984, one ♀ damage 7 mm, MACN No. 34689. 7 m depth, 5 September 1984, one ovig. ♀ dissected 7 mm, MACN No. 34690; one ♀ 5.8 mm, MACN No. 34691. 10 m depth, 5 September 1984, one ♀ 7.5 mm, MACN No. 34692. Collectors: Z. Lizarralde and H. Zaixso, donors: E. Gómez Simes and C. Pastor .

Remarks

All female specimens examined from the different Argentine localities agree closely with the female described and illustrated in Barnard and Barnard (1980) ( figure 13a ). The single male reported in the present collection is immature, and is not comparable with the male described by these authors. Comparisons made between females revealed some dissimilarities related to numbers of setae and spines on appendages and mouthparts. Thus, for example, the spine formula of antenna 2 peduncle article 4 is 3-3- 2 in Barnard and Barnard (1980), whereas it is 3-4- 3 in Golfito beach specimens ( figure 13b ), and in Golfo San José specimens the formulae are 3-4-1 and 3-3-3 at 7 and 10 m depth, respectively. Although this character is used in keys ( Barnard and Barnard, 1980) to distinguish the species of Fuegiphoxus , the variation in number of spines in the antennal formula seems to indicate that the character is not reliable. The number of spines, setae and aesthetascs on antennae 1 and 2 varies from one specimen to another, but with the same type and position of spines and setae in all of them. The mandibles are very similar, but the number of rakers varies ( figure 13c ), and the same may be seen with regard to the mandibular palp article 3, the apex of which bears eight spines in the specimen reported herein ( figure 13d ) but in the literature is reported as six or seven. The maxilliped inner plate has seven plumose setae instead of five and its outer plate has 11 apical spines instead of eight. Peraeopods 3 and 4, articles 4 and 5 have different numbers of facial spines in all females; the length of the main spine of article 5 is distinct, although the variation is slight; the spine formula of article 6 is 4 + 2 or 5 + 1 in the specimens examined ( figure 13e ), while Barnard and Barnard noted 3 + 2 and 4 + 2. Epimera 1–3 are similar in shape, but the margins show variations in the number of setae and setules ( figure 14a–c ); the shape of the posteroventral angle of the epimera is another character used by Barnard and Barnard to separate the Fuegiphoxus species.

Fuegiphoxus fuegiensis was discovered in Golfo Nuevo and Golfo San José, at a depth range of 7–80 m.

Figures

FIG. 13. Fuegiphoxus fuegiensis (Schellenberg, 1931). Female, Golfito beach: (a) lateral view; (b) antenna 2; (c) right mandible; (d) mandibular palp; (e) propodus and dactylus of peraeopod 4. Scales (µm): A: (a); B: (b, d, e); C: (c).

FIG. 14. Fuegiphoxus fuegiensis (Schellenberg, 1931). Female, Golfito beach: (a–c) epimera 1–3.

FIG. 1. Metharpinia iado n. sp. Allotype, ovig. female: (a) head, lateral view; (b) head, dorsal view; (c, d) antennae 1, 2; (e, f) right and left mandibles; (g) mandibular palp. Scales (µm): A: (a, b); B: (c, d); C: (e, f); D: (g).

FIG. 2. Metharpinia iado n. sp. Allotype, ovig. female: (a) lower lip; (b, c) maxillae 1, 2; (d) maxilliped; (e) gnathopod 1; (f) propodus and dactylus of gnathopod 1; (g) gnathopod 2; (h) propodus and dactylus of gnathopod 2. Scales (µm): A: (a–d); B: (e, g); C: (f, h).

FIG. 3. Metharpinia iado n. sp. Allotype, ovig. female: (a) peraeopod 3; (b) propodus and dactylus of peraeopod 3; (c) coxa 4; (d) peraeopod 4; (e) propodus and dactylus of peraeopod 4. Scales (µm): A: (a, c, d); B: (b, e).