Prismastrea organum, Vasseur & Lathuilière, 2021

Vasseur, Raphaël & Lathuilière, Bernard, 2021, Pliensbachian corals from the Western Tethys, Geodiversitas 43 (22), pp. 1187-1291 : 1279-1281

Prismastrea organum n. gen., n. sp.

( Fig. 65 )

urn:lsid:zoobank.org:act:42293C7A-7574-4594-BECA-57EB2C34910C

Nov. gen. 4 sp. 1 – Vasseur 2018: 270-271, fig. 3.67.

TYPE MATERIAL. — Holotype no. CPUN MA0704E6-1. STUDIED SAMPLES. — Four specimens: CPUN MA0704E6-1, MA0704E6-2, MA0704E6-3, MA0704E6-4.

ETYMOLOGY. — From the latin name organum (organ), refers to the typical basalt organ-like shape of the lateral faces of colonies.

TYPE HORIZON. — Margaritatus zone ( Upper Pliensbachian ). TYPE LOCALITY. — Koudiat Ech Chehem ( Guigou Plateau ), 33°27’10”N, 4°55’22”W, Morocco. GEOGRAPHIC AND STRATIGRAPHIC RANGES. — Pliensbachian of Koudiat Ech Chehem ( Guigou plateau, Middle Atlas of Morocco).

DESCRIPTION

Massive phacelo-cerioid colony with polygonal corallites multiplying by intratentacular budding. Radial elements are subcompact, subconfluent, straight or slightly curved septa, generally free (sometimes joined). Lateral faces of septa hold granules organized in carinae, typically montlivaltid in shape and distribution. Although, the symmetry and regularity of granules on both sides of the septa sometimes differ from the typical model. Distal and inner edges are ornamented with trabecular teeth that sometimes project in the axial zone, producing a parietal papillose columella. No endotheca observed. Wall of unknown nature but precisely delimited and apparently of the same nature as septa. No synapticulae observed.

Calicular diameter: 2 to 6 mm – Distance between calices centers: 2 to 4 mm – Number of septa: approximately 86 – Septal density: approximately 18 for 2 mm.

SIMILARITIES AND DIFFERENCES

Differs from Isastrea by its continuous and well defined wall, from Heterastraea by its montlivaltid septal structure and from Vallimeandropsis that is clearly meandroid.

Figures

FIG. 65. — Prismastrea organum n. gen., n. sp.: A, lateral view of specimen CPUN MA0704E6-2; B, distal view of specimen CPUN MA0704E6-1; C, transverse thin section in specimen CPUN MA0704E6-1; D, detail in transverse section of montlivaltid septal microarchitecture in specimen CPUN MA0704E6-1; E, longitudinal thin section in the specimen CPUN MA0704E6-1; E, longitudinal thin section in the specimen CPUN MA0704E6-3. Scale bars: A, 2 cm; B, 1 cm; C, 4 mm; D, 0.5 mm; E, 2 mm; F, 1 mm.