Propomatoceros sp. A

Vinn, Olev, Hryniewicz, Krzysztof, Little, Crispin T. S. & Nakrem, Hans A., 2014, A Boreal serpulid fauna from Volgian-Ryazanian (latest Jurassic-earliest Cretaceous) shelf sediments and hydrocarbon seeps from Svalbard, Geodiversitas 36 (4), pp. 527-540 : 532

Propomatoceros sp. A

( Fig. 4F )

MATERIAL AND LOCALITY. — See Table 1.

DESCRIPTION

Free tube part short, up to 3 mm long, with circular cross section and well-developed and relatively thick keel (1.0 mm thick at the base). Tube wall moderately thick, 0.75-1.0 mm at 4.5 mm tube diameter. Cementing part more than 15 mm long, keeled, poorly preserved.

DISCUSSION ffle specimen is assigned to the genus Propomatoceros due to its characteristic single, well-developed longitudinal keel. ffle fragmentary state of preservation precludes species identification.

Figures

FIG. 4. — Serpulids from seep carbonate bodies, Spitsbergen, Svalbard: A-E,?Pyrgopolon sp. A: A, large specimen showing the shape and external surface of the tube (PMO 217.365), seep 8; B, details of the outer surface of?Pyrgopolon sp. A, showing the smooth outer surface (PMO 217.365), seep 8; C, cross-section of the tube showing the thickness relation of inner and outer layers (PMO 217.365), seep 8; D, details of the outer prismatic layer (PMO 217.365), seep 8; E, details of the inner microgranular layer (PMO 217.365), seep 8. F, Propomatoceros sp. A, apertural view (PMO 217.354), seep 3. G, H, Nogrobs aff. quadricarinata Münster in Goldfuss, 1831: G, specimen showing shape and external ornament of the tube (PMO 217.356), Myklegardfjellet seep; H, details of the outer surface showing ornament composed of incomplete rings and concave surface of the tube (PMO 217.356), Myklegardfjellet seep. Scale bars: A, 5 mm; B, C, H, 1 mm; D, 200 µm; E, 100 µm; F, G, 2 mm.