Diagnoza

This species designated on the basis a suite of small uncrushed specimens, mostly internal casts, varying from 4 to 12 mm in diameter; umbilical edge is usually broadly rounded and not well marked, with walls which gradually become vertical or slightly undercut; in specimens with a wide umbilicus the extra width of the umbilicus is attained at the expense of the flanks, the inner portion of which forms the sloping umbilical walls, which have a more abrupt edge than the typical form; serpenticone stage persists up to about 6 mm diameter; constrictions average four per whorl; ornament consists of umbilical plications, which, when strongly represented, tend to become nodose at the umbilical edge; these plications bifurcate on the flank near the umbilicus, at the same time bending forward and degenerating into striae or subplications which usually are strongly marked on the internal cast; one extra stria is usually interpolated between the bifurcating primaries; there is a narrow hyponomic sinus which tends to be V-shaped in early adolescence, and a ventral sulcus is sometimes seen up to 6 mm diameter; transverse striations are spaced about three to the mm at the centre of the venter at 9 mm diameter; they are crenulate and there are subordinate spiral striae evenly distributed over the flanks; 4 different morphotypes with ornament and shape variants.

Porównanie

most evolute and coarsely ornamented of the R1b zone fauna and typical of its genus.

Autekologia

Występowanie geograficzne

Great Britain (Yorkshire), Belgium (Liège), France, (Nord-Pas-de-Calais) and Poland (Lublin Coal Basin). 

Zasięg czasowy

Carboniferous; Bashkirian

Materiały muzealne

Literatura

Bisat, W.S. & Hudson, R.G.S. 1943 . The lower Reticuloceras (R1) goniatite succession in the Namurian of the North of England. Proceedings of the Yorkshire Geological Society 24 (6): 383-440.

Korejwo, K. 1969. Stratigraphy and palaeogeography of the Namurian in the Polish Lowland. Acta Geologica Polonica 19 (4): 609-70.

Korejwo, K. 1986. Biostratigraphy of the Carboniferous deposits of the Świdnik blocks (Lublin Coal Basin). Acta Geologica Polonica 36 (4): 337-346