Micrabacia marylandica Stephenson, 1916

Baron-Szabo, Rosemarie C., 2008, Dendrophylliina, Caryophylliina, Fungiina, Microsolenina, and Stylinina, Zootaxa 1952, pp. 1-244 : 151-152

Micrabacia marylandica Stephenson, 1916

Pl. 13, figs 4a, b

v*1916 Micrabacia marylandica sp. nov.: Stephenson, p. 755, pl. 48, figs 1–4.

v1917 Micrabacia hilgardi n. sp.: Stephenson, p. 120, pl. 22, figs 1–6.

v1917 Micrabacia marylandica Stephenson : Stephenson, p. 121, pl. 22, figs 7–10.

1926 Micrabacia hilgardi Stephenson : Wade, p. 26, pl. 1, figs 3–4, 6–8.

1928 Micrabacia hilgardi Stephenson : Whitney, p. 226.

1933 Micrabacia hilgardi Stephenson : Wells, p. 156 (238).

1933 Micrabacia hilgardi occidentalis n. var.: Wells, p. 158 (240), pl. 15, figs 14–15.

2000 Micrabacia hilgardi, Stephenson 1916 : Löser, p. 51.

2000 Micrabacia hilgardi occidentalis Wells 1933 : Löser, p. 51.

2000 Micrabacia marylandica, Stephenson 1916 : Löser, p. 51.

2002 Micrabacia hilgardi Stephenson, 1917 : Baron-Szabo, p. 131.

2002 Micrabacia hilgardi occidentalis Wells, 1933 : Baron-Szabo, p. 131.

2002 Micrabacia marylandica Stephenson, 1916 : Baron-Szabo, p. 131.

Dimensions. d= 2–7 mm; s=up to 96; h=up to 3 mm.

Description. Cupolate, free, corallum flat, disc-like; septa arranged in 5 complete cycles in 6 systems; S1 and some of S2 slightly more dominant, join axially forming V-shapes similar as in the genus Deltocyathus ; remaining septa regularly alternating in length but subequal in thickness with thickened axial ends.

Remarks. Wells (1933, p. 154ff. [235ff.]) revised 14 species of Micrabacia , upon which he created a model that had several significant problems due to which the distinguishing of species is impossible (see discussion in Remarks of Micrabacia radiata [Goldfuss]). Therefore, based on the re-examination of type material, forms that have 1) 5 complete cycles in 6 systems developed in corallites ranging between 5–7 mm in diameter, and 2) septa that are unequal in thickness in that S1 and some of S2 are slightly more dominant and remaining septa that regularly alternate in length but are subequal in thickness with thickened axial ends, are considered synonymous.

Type locality of species. Maastrichtian of the USA ( E. costata zone, Monmouth Formation , Maryland) .

Distribution. Maastrichtian of the USA (Alabama, Mississippi, Tennessee, Texas).