Hyperiella macronyx (Walker 1906)

Hyperiella macronyx (Walker)

Hyperia macronyx Walker, 1906:452; 1907:7–8, pl. 1: fig. 1.–Barnard, 1930:412–413.–Emison, 1968:203–206 [food of Adélie penguin].–Hurley, 1969:33, map 5 [distribution].

DERIVATION OF NAME.–Not given; presumably from the Greek “macro” [=large] + “onyx” [=claw], referring to the long dactyls on P3–7.

TYPE-LOCALITY.–Two locations in the Ross Sea, Antarctica: (1) Coulman Island; (2) Discovery winter quarters, on tip of Cape Armitage, south side of Ross Island, McMurdo Sound.

DIAGNOSIS.–Length, up to 13 mm. Pereon not so plump as in other species of Hyperiella. Pleonite 3 with point on posterolateral margin. Mx2 with 3 spines at apex of outer lobe. Mxp without row of spines on distal margin of basal plate. P6 slightly longer than P5, both considerably longer than P7, which is subequal to P3–4. S7 of P3–7 elongate. Telson slightly longer than wide, about half as long as peduncle of Up3.

RELATIONSHIPS.–Easily distinguished from its congeners by the characters given in the key.

DISTRIBUTION.–Known only from the Ross Sea.

III. Hyperioides Chevreux

Hyperioides Chevreux, 1900:143.

Parahyperia Vosseler, 1901:56 [conditional name].

DIAGNOSIS.–Small species with body rather compressed laterally. Head globular, produced anteriorly above insertion of A1; eyes occupying most of its surface or limited entirely to dorsal surface. Pereonites 1–2 fused in both sexes. Coxae fused with pereonites. Posterior elevation of ♂ pleonite 1 pronounced. Telson rather short. ♀ Al 2–3–merous. ♀ A2 1–merous, moderately long, with characteristic sinuous shape in lateral view; gland cone rounded below. Md with dentate incisor; palp absent in ♀. Mx1 outer lobe with 3 large terminal spines and a smaller subterminal spine. Mx2 outer lobe with 1 terminal and 1 subterminal spine; inner lobe with 1 terminal spine. Mxp inner lobe well developed, with 2 terminal spines. P1–2 chelate, with spoon-shaped carpal process bearing marginal spines. P5–6 distinctly longer than P3–4 and P7; dactyls of P5–7 long, with comb of fine setules on proximal 3rd of anterior margin. Outer rami of uropods notched.

DERIVATION OF NAME.–Not given; presumably from Hyperia + the Greek “oides” [=resembling].

TYPE-SPECIES.–By monotypy, Hyperioides longipes Chevreux, 1900. Gender feminine.

REMARKS.–The above diagnosis modifies that of Chevreux (1900) to include characters which this study has convinced me are significant at the generic level. Until now Hyperioides has been monotypic, but I am transferring to it a second species, Hyperia sibaginis Stebbing (1888). This action was foreshadowed by Vosseler’s (1901) misidentification of H. longipes as H. sibaginis; Vosseler was of course unaware of Chevreux’s description of H. longipes. Chevreux’s diagnosis of Hyperioides accommodates H. sibaginis except for his statement that the eyes are limited to the upper part of the head.