Platidia anomioides (Scacchi & Philippi in Philippi, 1844)

Hansen, Jesper, 2024, Brachiopods of the Norwegian fauna northern North Atlantic and Arctic, with a focus on, Fauna norvegica 43, pp. 12-68 : 46-47

Platidia anomioides (Scacchi & Philippi, in Philippi, 1844)

Figures 42 , 43

Orthis anomioides Scacchi & Philippi in Philippi (1844), p. 69 –70, pl. 18, fig. 9.

Terebratula appressa Forbes, 1844, p. 193 .

Platidia anomioides – Costa (1852), p. 48, pl. 3, figs. 4 and 6.

Morrisia anomioides – Davidson (1852c), p. 79 –80, pl. 14, fig. 29.

Morrisia davidsoni Deslongchamps, 1855, p. 443 , pl. 10, figs. 20a–d.

Terebratula (Morrisia) anomioides – Lovell (1861), p. 184.

Terebratula (Morrisia) anomioides – Reeve (1861), pl. 10, fig. 40.

Terebratula (Morrisia) davidsoni – Reeve (1861), pl. 10, fig. 42.

Argiope (Zellania) davidsoni – Weinkauff (1867), p. 290.

Platidia davidsoni – Dall (1870), p. 143.

Platydia anomioïdes – Jeffreys (1878), p. 411.

Platydia davidsoni – Davidson (1880), p. 21.

Platidia seminula Philippi – Dall (1920) [partim], p. 332.

Description: Shell typically very uneven, concavoconvex to ventribiconvex, shaping itself after the substratum. Outline circular to transversely oval, but juveniles can be more egg-shaped. Hinge line straight and shorter than greatest shell width. Ornamentation of concentric growth lines, with randomly distributed pustules (tubercles) on ventral valve. Pustules missing on juvenile shells. Shell matrix endopunctate. Colour yellowish-brown or white. Pedicle foramen large and extending well into posterior part of dorsal valve. Deltidial plates narrow. Short brachidium (=lophophoral support) when fully developed, forming a brachial loop supported by short median septum. Median septum very high triangular and can reach slightly anterior of mid-valve length. Very short setae along valve margin. Maximum shell length 8 mm.

Depth range: 8–2190 m depth (Logan 2007).

Temperature range: -1.2–12.0˚C ( Carpenter et al. 1869; this study).

Salinity range: 35.2–35.3 ( Thomsen 2001).

Substrate: Attached to pebbles, shells and corals ( Davidson 1887; Brunton & Curry 1979; Logan 1979; Thomsen 2001). Found on all from mud- to stone-dominated bottoms ( Thomsen 2001).

Geography: SW of Faroe Islands, Florida, North of Shetland, the Hebrides, Western Approaches, Bay of Biscay, Portugal, Mediterranean, Azores, Morocco, Canary Islands, Cuba, the West Indies, Red Sea, Argentina, South Africa, southernmost S America, Prince Edward Islands, and Antarctica ( Fischer & OEhlert 1891, 1892; Cooper 1973a; Brunton & Curry 1979; Thomsen 2001; Logan et al. 2007, 2008; Zezina 2008).

Figures

Figure 42. Platidia anomioides. a–e: dorsal, ventral, anterior, posterior and lateral views of specimen; f: interior view of a dorsal valve; g: interior view of a ventral valve; h–i: dorsal and ventral views of juvenile specimen. All specimens are housed at the Zoological Museum of Copenhagen, Natural History Museum of Denmark. The shells all belong to the old collection of Chr. viii. Scalebar 1mm. Photos: Jesper Hansen.