Hyperia crassa Bowman 1973

Hyperia crassa

Hyperia spinigera Bovallius.–Barnard, 1932:273–4 [♀ only], fig. 160b.

DERIVATION OF NAME.–The specific name, from the Latin “crassus” [=thick, fat], refers to the broad protopods and endopods of the uropods.

TYPES.–All from Ombango Cruise 12 in the Gulf of Guinea. Holotype ♀, USNM 137502, station 298 (Grand Schmidt 2), 3o01′S, 9°25′E, 300 meters of wire, 1 May 1960, 1040 hrs. Allotype ♂, USNM 137503, station 302 (Grand Schmidt 19), 4°47′S, 10°42′E, 1100 meters of wire, 4 May 1960, 0450 hrs. Paratypes, 3 ♀ USNM 137504, station 300 (Grand Schmidt 11), 3°48′S, 19°08′E, 200 meters of wire, 2 May 1960, 1800 hrs.

DIAGNOSIS.–Body rather compact and heavyset, length 12–15 mm. Head unusually large, longer than pereonites 1–3 combined, in lateral view much longer dorsally than ventrally. Pereonites with distinctive dorsal profile shown in Figure 18a; pereonite 2 highest, pereonite 7 concave anteriorly, convex posteriorly; pereonites 2, 3, and 4 with transverse folds. Pleonal epimera with pointed posteroventral corners; posterolateral margin of pleonite 3 only weakly convex. Proximal segment of Md palp much shorter than distal segments; incisor with 9 or 10 teeth. Mxp inner lobe long, with long apical spines. Segments of P1–2 with well-developed spines; s2 of P1 with very convex anterior margin. P3–4 with very few spines on posterior margins of s4–5. P5–7 unarmed, with rather narrow s2. Up2–3 with very broad protopods and endopods.

RELATIONSHIPS.–Barnard (1932) called attention to the very broad uropods of a female Hyperia which he identified as H. spinigera. In his discussion he gave the impression that he had some reservations about this identification, and these reservations have proved to be entirely justified. This female, loaned to me by the British Museum (Natural History), closely resembles the Ombango females of H. crassa, as can be seen by comparing Figures 18 and 19. The long head and broad uropods on both Ombango and Discovery females, unique features of H. crassa, clearly establish their specific identity.

DISTRIBUTION.–West coast of Africa, 3–5°S (Ombango stations). SE of Cape Verde Islands, 13°01′N, 21°34′W, Discovery station 298 (Barnard, 1932).

II. Hyperiella Bovallius, 1887b

DIAGNOSIS.–Body small to moderate sized; pereon rather plump; pereonites all separate. ♀ A1 and A2 4–merous. Md palp present in ♀; incisor serrate. Mx1, inner lobe with 5 terminal spines. Mx2 with 1 terminal spine on inner lobe, 2–3 on outer lobe. Mxp, inner lobe well developed, ending in 2 spines; outer lobes separate. P1 subchelate; P2 chelate; posterior margin of s6 serrate in both P1 and P2. P3–4, posterior margins of s5 and s6 serrulate, that of s5 bearing a few slender spines. P5 (or P5–6) much longer than P3–4; P7 (or P6–7) subequal to P3–4. S7 of at least P3–5 very long. Up3 elongate, except in H. macronyx.

DERIVATION OF NAME.–Not given, presumably diminutive of Hyperia. Gender feminine.

TYPE–SPECIES.–Designated by Bovallius, 1889, Hyperiella antarctica Bovallius, 1887b.

REMARKS.–The foregoing diagnosis is modified from the original by Bovallius in order to accommodate Hyperia macronyx Walker (1906). H. macronyx differs from the two other members of the genus in that both P5 and P6 are elongate and Up3 is shorter, but in other respects it is more similar to Hyperiella antarctica and H. dilatata than to any of the species of Hyperia as restricted herein. The alternative to transferring H. macronyx to Hyperiella would be to propose a monotypic genus for Walker’s species. The latter course seems less desirable, since it would not call attention to the similarity of H. macronyx to H. antarctica and H. dilatata.

Hyperiella is close to Hyperia, but is smaller than any species of Hyperia, and P5 (or P5–6) are relatively longer. In some respects it resembles Parathemisto; P3–4 approach the prehensile condition of these legs in Parathemisto, and elongate uropods and characteristic of Parathemisto.