Novocrania anomala ( Müller, 1776 )

Hansen, Jesper, 2024, Brachiopods of the Norwegian fauna northern North Atlantic and Arctic, with a focus on, Fauna norvegica 43, pp. 12-68 : 23

Novocrania anomala ( Müller, 1776)

Figures 4–6

Patella Kermes da Costa & Humphrey, in da Costa (1770).

Patella anomala Müller, 1776, p. 237 .

Orbicula anomala – Cuvier (1798), p. 435 –436.

Crania personata Lamarck, 1801, p. 138 .

Orbicula norwegica Lamarck, 1801, p. 140 .

Patella distorta Montagu, 1815, p. 195 , pl. 13, fig. 5.

Orbicula norvegica – Schumacher (1817), p. 176 –177, pl. 21, figs. 2a–c.

Crania personata Blainville [non Lamarck, 1801], 1818, p. 312.

Criopus anomalus – Fleming (1822a), p. 499.

Crania ringens Hoeninghaus, 1828, p. 4 –5, figs. 2a–b.

Crania rostrata Hoeninghaus, 1828, p. 5 , figs. 3a–b.

Crania anomala – Lovén (1846), p. 183.

Crania norvegica – Sowerby (1847), p. 368, pl. 73, figs. 15–17.

Criopus orcadensis Leach, 1852, p. 358 , pl. 13, figs. 6–8.

Crania ( ? anomala var.) Pourtalesii Dall, 1871, p. 35 , pl. 1, fig. 7.

Crania (Crania) anomala – Dall (1873) [partim], p. 198.

Crania Pourtalesii – Dall (1881), p. 104.

Neocrania anomala – Lee & Brunton (1986), p. 150 –152.

Neocrania pourtalesi – Lee & Brunton (1986), p. 150.

Crania (Neocrania) anomala – Nielsen (1991).

Novocrania anomala – Lee & Brunton (2001), p. 5.

Novocrania pourtalesi – Lee & Brunton (2001), p. 5.

Description: Shell transverse oval or subangular with low conical dorsal valve and nearly straight and narrow posterior margin. Holoperipheral growth with apex slightly behind mid-valve length. Ventral valve cemented to hard substrate. Shell smooth, with fine radiating striation or reflecting surface of substrate. Shell matrix endopunctate. Dark brown or reddish outer layer, with light grey inner shell layer. No hinge. Dorsal interior with distinct muscle scars. Anterior adductor muscle scars not raised or slightly raised. Tiny dorsal ridge. Ventral interior rarely with calcified posterior adductor muscle scars. Anterior adductor muscles attached to organic rostellum. Outer margin poorly defined and relatively densely tuberculate. Maximum width 25 mm.

Depth range: 4–1805 m depth, though mostly 10–400 m depth ( Zezina 2010; Robinson 2017; Toma et al. 2022; this study). Observations from visual surveys of the coastal waters of Norway indicate that dense populations are likely widespread on submarine cliff walls and rocky bottoms in these latitudes in a depth zone from the lower part of a belt of dense serpulid tubeworm populations and downwards ( Figure 5 ). In the Vestfjord area of Nordland, this brachiopod zone seems to be mostly between 100 and 200 m in depth; however, it extends to shallower depths in many places. This compares well with visual surveys in the Mediterranean where dense populations were found especially frequent on cliff walls at 80–500 m depth, though with geographic variations (Toma et al. 2002).

Temperature range: 1.8–11.0˚C ( Grieg 1924; this study). However, Brand et al. (2003) gave the temperature range 6–21˚C, indicating a much higher upper range than found in the present study.

Salinity range: 29–37 ( Brand et al. 2003).

Oxygen range: 55–113% for oxygen saturation of bottom water (this study).

Current velocity: Mean current velocity between 1.1–9.5 cm /s, with daily maxima generally between 0–30 cm /s, with a maximum velocity of 4.4–42.5 cm /s over 1 month of measurements (this study).

Substrate: Attached to cliff faces, boulders, artificial substrates and the hard skeletons of other organisms ( Brunton & Curry 1979; Toma et al. 2022; this study). Mostly collected on sea floors

Figures

Figure 4. Novocrania anomala. a–c: dorsal, lateral and ventral views of dorsal valve, TSZBr 2396, Lødingen st. viii in Nordland, Norway, 70–80 m; d: specimen attached to coral with the ornament of the coral impressed on the shell, Brettingsneset in Trondheimsfjorden, Trøndelag, Norway, 100–400 m (JH); e–g: dorsal, posterior and ventral view of dorsal valve with soft tissue preserved, TSZ 3210 (APN), Øksfjord in Finnmark, Norway, 94 m; h: interior of ventral valve, Nordnes at Alta in Finnmark, Norway, 87 m (APN). Scalebar 1mm. Photos: Jesper Hansen.

Figure 5. Cliff face covered by both live and dead specimens of Novocrania anomala. 121 m depth in a Norwegian fjord. Photo: Akvaplan-niva.

Figure 6. Distribution of Novocrania anomala.