Fig. 15 A–C
Scalpellum michelottianum Seguenza, 1876: 381, pl. 6, figs 15–25; Withers, 1953: 225; de Alessandri, 1895: 263 (part); 1897: 47, 1906: 251; Pilsbry, 1907a: 32; Withers, 1953: 225.
Scalpellum velutinum Hoek, 1883: 96, pl. IV, figs 10–11, pl. 9, figs 7–9; 1907: 59,79, 87; 1914: 4; Weltner, 1897: 251; Weltner, 1922: 75; Gruvel, 1902a: 56, 136, pl. 2, figs 3c, 10a–b, 14, pl. 3, figs 1, 27–31, pl. 4, figs 6, 11–22; 1905: 73, fig. 83; 1912: 2; 1920: 27, pl.1, figs 8–10, pl. 7, fig. 4; Pilsbry, 1907a: 26, pl. 3, fig. 2–3; Annandale, 1906b: 389; 1908: pl. 4, fig. 7; 1913: 229; Calman, 1918: 108–109; Barnard, 1925: 1; Nilsson-Cantell, 1927: 743, fig. 1; 1928: 4; 1931: 7; 1938: 8; Broch, 1931: 18; Stubbings, 1936: 28, fig. 12; 1967: 234; Tarasov & Zevina, 1957: 24, fig. 9H; O’Riordan 1967: 287; Zevina, 1972: 43, fig. 2.
Scalpellum eximium Hoek, 1883: 100, pl. IV, figs 6–7, 10; Weltner, 1897: 247.
Scalpellum erectum Aurivillius, 1898: 192; Gruvel, 1905: 74.
Scalpellum sordidum Aurivillius, 1898: 190.
Scalpellum alatum Gruvel, 1900: 192; 1902: 57.
Arcoscalpellum velutinum: Weisbord, 1977: 273 –278, pl. 32, figs 1–2.
Trianguloscalpellum michelottianum: Liu & Ren, 1985: 207, fig. 14, pl. 4, figs 10–12; Ren, 1989: 442, fig. 6; Huang, 1994: 517; 2001: 318.
Arcoscalpellum michelottianum: Withers, 1953: 225–229, pl. 37, figs 1–10, pl. 64, fig. 4; Newman & Ross, 1971: 71, fig. 34, pl. 9b; Laksmana Rao & Newman, 1972: 76, fig. 5; Zevina: 1978b: 1350, 1981a: 343–344, fig. 263; Rosell, 1989: 17, pl. 10, figs d–e; 1991: 23; Jones et al., 1990: 5, 26; Zevina & Shreider, 1992: 40; Jones, 1992: 168–172, figs 16–17, table 10; Shreider, 1994: 159; Klepal & Nemeschkal, 1995: 183, pl. 1C; Foster & Buckeridge 1995b: 169–170, fig. 2f–h; Jones et al., 2000: 254; Young, 1998b: 19, figs 13a–d, 14; 1999a: 181; 2001a: 731–732, fig. 18; 2001b: 464, fig. 7; 2004: 26; Poltarukha & Zevina, 2006a: 155–156, fig. 4; Liu & Ren, 2007: 241–244, fig. 104; Chan et al., 2009: 131–133, figs 112–114; Poltarukha, 2012: 36, fig. 9; 2013: 54–55, fig. 3.
Material examined. Holotype of S. velutinum NHM UK 2013.1086, Stn 335: Atlantic, Eastern Central (Mid Atlantic Ridge); 3500m.
Additional specimens. S. velutinum, two juveniles, NHM UK 2013. 1087–1088, Stn III; Atlantic, Northeast (off Cape Sao Vincente, Portugal); 1646 m.
Holotype of S. eximium NHM UK 2013.1089, Stn 135E: Atlantic, Southeast (off Tristan da Cunha); 1830 m.
Diagnosis. The diagnosis of Hoek (1883) contained plate characters only.
Supplementary descriptions. Newman & Ross (1971) described the appendages of early stages that had been tentatively assigned to A. michelottianum. Jones (1992) also provided appendage descriptions, but these differ from those of Newman & Ross (1971). Chan et al. (2009) published photographs of the mouthparts.
Distribution. Worldwide. Known depth range 64 to 5190 m.
Habitat. Attached to gorgonian corals, gastropod shells and rocks.
Remarks. Although this species has been reported numerous times worldwide, there is considerable confusion concerning its morphology. There appears to be marked variation in morphology according to the stage of ontogenetic development, for example the degree of projection and the umbo position of the carinal latus can vary during development. Newman & Ross (1971) found the carinal border of the plate was not projecting and the umbo was apical, whereas Hoek (1883) found the umbo projecting on the top of the carinal margin. In contrast, Chan et al. (2009) noted the umbo in the middle region of the carinal margin and Zevina (1981a) reported the umbo to be higher than the middle of the margin. The current synonymy is based mainly on Withers (1953), but Hoek’s specimens of S. velutinum and S. eximium were assigned to A. michelottianum based only on shell plate details. These synonymies should be revisited when all the appendage characters are considered.
The name Scalpellum michelottianum was firstly proposed by Seguenza in 1876 for a reconstructed fossil from Italy. Thus, the recent specimens from the North Atlantic, the types of S. velutinum and S. eximium, described by Hoek (1883) have no type status with regard to A. michelottianum.