Genus Spiraserpula Regenhardt, 1961
Spiraserpula scrupea Regenhardt, 1961
Pl. 2, figs. 9-11.
Description – Tube medium sized, slowly increasing in diameter, forming several spirals, either stacked on one another or in close proximity. A strong attachment to the substrate is achieved by construction of more or less low spirals with a wide base. Between the spirals, non-spiral tube portions may be present. As in Cementula, the outer tube layer is like sugar coating, obscuring the sutures. Commonly, an umbilicus is present and the anterior portion of the tube has a keel. Widely spaced birdwing-like peristomes (‘alae’) may occur. On the inner surface of the posterior portion of the tube there are internal structures for anchorage of the animal. These consist of three keels situated at approximately equal distances from each other and protruding into the lumen. In Recent species of Spiraserpula, the animal can be drawn out of its aperture only by tearing it to pieces. A free tube portion may occur rarely and may bear quadripartite peristomes similar to those in Cementula.
Remarks – Specimens from the type Maastrichtian were described as Spiraserpula sp. 1 by Pillai (1993). It is possible that S. scrupea and S. versipellis Regenhardt, 1961, from the chalk facies of northern Germany, are conspecific. The only remarkable difference is the lack of granulation in the former.
Distribution – Emael and Nekum members(?); Meerssen Member.