Rouillieria aff. rasile Smirnova, 1975

Sandy, Michael R., Hryniewicz, Krzysztof, Hammer, Øyvind, Nakrem, Hans Arne & Little, Crispin T. S., 2014, Brachiopods from Late Jurassic-Early Cretaceous hydrocarbon seep deposits, central Spitsbergen, Svalbard, Zootaxa 3884 (6), pp. 501-532 : 521

Rouillieria aff. rasile Smirnova, 1975

Fig. 8.17–8.20

1975 aff. Rouillieria rasile new species —Smirnova, p. 350, pl. X, fig. 3.

Material and occurrence. Seep 8 (PMO 224.929).

Discussion. One damaged specimen that has a similar outline to the specimen figured by Smirnova (1975). The Spitsbergen specimen has a slightly more shouldered appearance at the hinge line compared to Smirnova’s figured specimen. The long, very wide ventrally concave hinge plates and apparently relatively small crural bases ( Smirnova 1975, fig. 8) do point to this species as having internal structures that are atypical of Rouillieria . However, in the diagnosis for Rouillieria Lee et al. (2006, p. 2098) state “outer hinge plates broad”. The diagnosis for the genus also refers to crural bases that form lateral umbonal cavities reaching the valve floor (e.g. serial sections of R. michalkowii in Makridin (1964, fig. 83)). However, these lateral umbonal cavities presumably develop due to secondary shell overgrowth and therefore depend on the growth stage of the sectioned specimen. It is probable that these cavities are more likely to develop in maturing or gerontic individuals (or they may even become infilled with secondary shell material in the latter).

Smirnova described Rouillieria rasile from Chevkino Village , Ryazan Province, Russia and it was recorded from the “Berriasian, Ryazan horizon” ( Smirnova 1975, p. 351) .

Stratigraphic and geographic distribution. Upper Volgian of Spitsbergen.

Figures

FIGURE 8. 1–8. Rouillieria cf. michalkowii (Fahrenkohl). 1–4. PMO 227.422, seep 13, dorsal, ventral, lateral, and anterior views. 5–8. PMO 227.420, seep 8, dorsal, ventral, lateral, and anterior views. Specimen serially sectioned (Figure 9). 9–16. Rouillieria aff. ovoides (Sowerby). 9–12. PMO 224.926, seep 8, dorsal, ventral, lateral, and anterior views. 13–16. PMO 227.426, seep 13, dorsal, ventral, lateral, and anterior views. 17–20. Rouillieria cf. rasile Smirnova, PMO 224.929, seep 8, dorsal, ventral, lateral, and anterior views. Scale bars = 1 cm for each specimen.