Crella (Crella) hennequinae Goodwin & Berman & Hendry 2019, sp. nov.

Crella (Crella) hennequinae sp. nov.

(Figure 7, Table 5)

lsid:zoobank.org:act: 81218B8F-1C10-4711-A2E2-D51FD220A60

Type material: Holotype: BELUM. Mc 2015.725 Port Charcot, Booth Island (65°03.853’S, 64° 01.868’W), depth 6–16 m; collected by C. Goodwin and E. Priestley, 23/02/2015.

Paratypes: BELUM. Mc 2015.693 Vieugue Island (65°38.758’S, 65° 12.540’W), depth 10–22 m; collected by C. Goodwin and E. Priestley, 23/02/2015. BELUM. Mc 2015.640 Rocks near San Martin Islands (65°41.297’S, 65° 20.091’W), depth 6–21 m; collected by C. Goodwin and E. Priestley, 17/02/2015.

Other specimen: BELUM. Mc 2015.736 Port Charcot, Booth Island (65°03.853’S, 64° 01.868’W), depth 6–16 m; collected by C. Goodwin and E. Priestley, 23/02/2015.

Diagnosis. Southern Ocean Crella (Crella) with one category of lightly and evenly spined basal acanthostyles.

Etymology. Named after Juliette Hennequin, first mate of the expedition vessel the Hans Hansson, in recognition of her support.

External morphology. In situ appearance (Figure 7A): Bright orange crust with prominent pore sieves. Growing over bedrock. Some patches were very large (> 50 cm in diameter).

Preserved appearance. Fairly firm pale yellow crust with smooth, detachable, surface on which pore sieves are clearly visible. Storage ethanol has turned orange.

Skeleton (Figure 7B): Plumose. Strongly hispid ascending columns of acanthostyles and tornotes. Dense ectosomal layer of acanthoxea.

Spicules: Measurements given here are from the holotype BELUM.Mc2015.725. See Table 5 for dimensions of paratypes.

Acanthostyles (Figure 7C,D): 454(465)477 by 16(20) 26 µm. Slightly curved with small spines very sparsely scattered along their length, in some spicules these are so sparse that they initially appear smooth. The heads are not tylote. There is no secondary class of echinating acanthostyles.

Ectosomal anisotornotes (Figure 7E): 294(325)353 by 7(11) 15 µm. Slightly fusiform tornotes with asymmetrical ends, one end usually smoothly tapered and one more abruptly pointed.

Ectosomal acanthoxeas (Figure 7F): 53(62)74 by 4(7) 10 µm. Often slightly curved. Entirely spined with large spines.

Remarks. These specimens are assigned to Crella as they possess an ectosomal crust of acanthoxeas and do not have chelae. As basal acanthostyles echinating the substrate are present they are assigned to Crella (Crella) (Van Soest 2002a). There are currently only five valid species of Crella (Crella) two of which, Crella (Crella) aurantiaca Bertolino, Calcinai & Pansini, 2009 and Crella (Crella) tubifex (Hentschel, 1914), have been recorded from the Antarctic. C. aurantiaca differs from our specimen in having two categories of basal acanthostyles. The form of both the categories of acanthostyles also differs in that they have very dense clumps of large recurved spines on their heads, whereas our specimen has very small spines evenly spread along the length of the shaft. Crella (Crella) tubifex possesses amphistrongyles rather than tornotes, and ectosomal acanthostrongyles rather than acanthoxeas.