Dimorphastrea? menchikoffi ( Beauvais, 1986 ), 1850

Vasseur, Raphaël & Lathuilière, Bernard, 2021, Pliensbachian corals from the Western Tethys, Geodiversitas 43 (22), pp. 1187-1291 : 1240

Dimorphastrea? menchikoffi ( Beauvais, 1986)

( Fig. 35 )

Dimorphastraea [sic] menchikoffi Beauvais, 1986: 51 , pl. 13, fig. 3. — Vasseur 2018: 168-169, fig. 3.26.

TYPE MATERIAL. — Holotype: MNHN.F.R11641, Beauvais 1986: 51, pl. 13, fig. 3. TYPE HORIZON. — Domerian . TYPE LOCALITY. — Beni Tadjit , Morocco. STUDIED SAMPLE. — Holotype MNHN.F.R11641. GEOGRAPHIC AND STRATIGRAPHIC RANGES. — Pliensbachian of Beni Tadjit ( Morocco).

DESCRIPTION

Small, fungiform thamnasterioid colony fixed by a peduncle. Calices are concentrically arranged, suggesting a circumoral mode of gemmation. Radial elements are pennular, straight or flexuous biseptal blades that are subcompact or porous (a thin section would be necessary to conclude about this question). The projections of dissociated septal trabeculae at the axis of the corallite produce a papillose columella. Endotheca not observed but it would be rare according to Beauvais 1986. Synapticulae probably present.No wall separating the calices. A concentrically wrinkled holotheca covers the base of the colony.

Calicular diameter: approximately 2 to 4 mm – Distance between calices centers: 2 to 4 mm – Number of septa: 23 to 38 – Septal density: 6 to 7 per 2 mm.

REMARKS

We maintain with doubt this specimen within the genus Dimorphastrea d’Orbigny, 1850 (and not Dimorphastraea Fromentel, 1857 as it was described in Beauvais [1986]) because the specimen preparation does not allow to confirm that septa are compact. A thin section would be necessary to verify that this taxon does not belong to Dimorpharaea Fromentel, 1861 .

Figures

FIG. 35. — Dimorphastrea? menchikoffi (Beauvais,1986):A, distal view of the specimen MNHN.F.R11641; B, lateral view of the specimen MNHN.F.R11641; C, proximal view of the specimen MNHN.F.R11641; D, detail in distal view of the specimen MNHN.F.R11641; E, detail in distal view of the specimen MNHN.F.R11641. Scale bars: A, 4 mm; B, C, D, 1 cm; D, 5 mm; E, 3 mm.