Propomatoceros sp. 3

Słowiński, Jakub, Vinn, Olev, Jäger, Manfred & Zatoń, Michał, 2022, Middle and Late Jurassic tube-dwelling polychaetes from the Polish Basin: diversity, palaeoecology and comparisons with other assemblages, Acta Palaeontologica Polonica 67 (4), pp. 827-864 : 845

Propomatoceros sp. 3

Fig. 8D.

Material.— One specimen attached to a bivalve shell from the lower Kimmeridgian ( Upper Jurassic ) of Małogoszcz , the Mesozoic margin of the Holy Cross Mountains, Poland (see Table 1); GIUS 8-3747 .

Description.—The tube large, robust, and significantly increasing in diameter (up to 4 mm). The entire specimen coiled and forms a loop. A very prominent, slightly undulating keel on the top of the tube, which results in its subtriangular cross-section. Otherwise, the surface completely smooth, lacking any ornamentation. Flanges are very well-developed.

Remarks.—The specimen is assigned to the genus Propomatoceros because of the large size, the very distinctive keel and very well-developed flanges. Nevertheless, it seems to differ from other species of Propomatoceros by its completely smooth surface lacking any growth lines or ornamentation except for the keel.