Rosselia Dahmer, 1937

Revised diagnosis. (After Uchman & Krenmayr 1995) Vertical to inclined, downward tapering, straight or curved burrow with a funnel-shaped, bulbous or fusiform aperture containing a thick concentric, spiralled or eccentric lining around one or several, passively filled, cylindrical tube(s). Secondary successive branching may occur.

Ichnotaxonomy: R. socialis is the most common ichnospecies of the ichnogenus Rosselia and probably the only valid one.

Diagnosis Conical to irregularly bulbous or funnel - shaped structures, vertical to horizontal, consisting either of a small central burrow surrounded by broad, concentric, cone-in-cone laminae, or of spreitelike helicoid swirls surrounding a cone, both tapering downward to a concentrically walled, subcylindrical stem.

Diagnosis: Irregularly bulbous to conical or funnel-shaped structures predominantly vertical, comprising a central shaft surrounded either by a concentrically layered wall or by helicoid swirls of spreitelike, closely appressed small burrow fills.