Hircella cornigera (Haswell, 1879)

Guerra-García, J. M., 2006, Caprellidae (Crustacea: Amphipoda) from the Great Barrier Reef and Adjacent Localities, Records of the Australian Museum 58, pp. 417-458 : 425

Hircella cornigera (Haswell, 1879)

Fig. 12

Caprella cornigera Haswell, 1879: 347–348 , pl. 23: fig. 5.

Hircella cornigera Haswell, 1885: 999 ; Mayer, 1890: 16–17, pl. 5: figs. 10–11, pl. 6: figs 3–22; Mayer, 1903: 31–32; Stebbing, 1910: 652.

Material examined. 13, 1♀, AM P47048, Boat Rock, North Stradbroke Island , Queensland, 27°25.21'S 153°33.28'E, bryozoans, hydrozoans and brown algae, 28 m, 21.8° C, R.T. Springthorpe, 3 Jun 1993 .

Remarks. In H. cornigera , pereopod 5 is reduced to a tiny article in males, and is absent in females. The type material of Hircella cornigera is lost (Springthorpe & Lowry, 1994).

Distribution. Previously known only from the type locality, Port Jackson, New South Wales, Australia (McCain & Steinberg, 1970); a new record for Queensland, Australia. Paratype female. Body length 3.2 mm. Antenna 1 flagellum 3-articulate ( Fig. 7B). Propodus palm of gnathopod 2 ( Fig. 10E) without distal projection. Oostegites not setose ( Fig. 7B). Pereopod 5 ( Fig. 11B) twice as long as in male, without setae and curved. Abdomen ( Fig. 11G) without small projections.

Remarks. Mayer (1882) established the genus Hircella mainly on the basis of the absence of pereopod 5. The genus Liriarchus Mayer, 1912 is also characterized by the absence of pereopod 5 in males or extremely reduced in females. However, Hircella and Liriarchus can be differentiated by the abdomen: two pairs of appendages are present in Hircella instead of one pair in Liriarchus . The present specimens collected from Queensland are assigned to Hircella on the basis of the presence of two pairs of appendages in the abdomen. Hircella presently includes H. berentsae n.sp., H. cornigera (Haswell, 1879) , and H. inermis Guerra-García & Takeuchi, 2004 , described from Tasmanian waters. Hircella berentsae n.sp. differs from H. cornigera , the type species of the genus, mainly on the basis of the following features: (1) pereopod 5 is present in females of H. berentsae but absent in females of H. cornigera ; (2) the body is smooth in H. berentsae but provided with large dorsal acute projections on pereonites 3–5 in H. cornigera ; and (3) antenna 1 is clearly shorter than half the body length in H. berentsae but longer in H. cornigera . Although H. berentsae n.sp. is closer to H. inermis , several constant differences indicate that both are valid species: (1) the adult body length of H. inermis is about 10 mm in contrast to 3–4 mm in H. berentsae ; (2) pereopod 5 is absent in males of H. inermis but present in males of H. berentsae ; (3) the antenna 1 flagellum is eightarticulate in males of H. inermis but four-articulate in H. berentsae ; (4) the first pair of abdominal appendages is 2- articulate in H. inermis but one-articulate in H. berentsae ; (5) the distal article of the mandibular palp bears six apical setae in H. inermis and 3 or 4 in H. berentsae .

Most morphological characters of H. berentsae are constant in all specimens examined. Nevertheless, the number of apical setae in the distal article of the mandibular palp varies, being three or four depending on the specimens.

Distribution. Elizabeth and Middleton Reefs, Tasman Sea, and Freshwater Bay, Queensland.