Hispaniastraea ousriorum Boivin, Vasseur, Lathuilière, Laz

Vasseur, Raphaël & Lathuilière, Bernard, 2021, Pliensbachian corals from the Western Tethys, Geodiversitas 43 (22), pp. 1187-1291 : 1231-1234

Hispaniastraea ousriorum Boivin, Vasseur, Lathuilière, Laz ă r, Durlet, Martindale, El Hmidi & Martini, 2019

( Fig. 30 )

Hispaniastraea ousriorum Boivin, Vasseur, Lathuilière, Lazăr, Durlet, Martindale, El Hmidi & Martini, 2019: 10 , fig. 7-8.

Hispaniastraea sp. 1 – Vasseur 2018: 219-220, fig. 3.47.

TYPE MATERIAL. — Holotype no. SB367 (Collections of the Direction of Geology, Ministère de l’Énergie, des Mines et du Développement durable – Département de l’Énergie et des Mines, Rabat, Morocco). TYPE HORIZON. — Upper Pliensbachian , Lower Jurassic . TYPE LOCALITY. — Koudiat Ech Chehem , Guigou Plateau , Middle Atlas Mountains , Morroco. Studied samples. — Three specimens: CPUN AM16160-3, CPUN AM16188-5, CPUN CDAm1. GEOGRAPHIC AND STRATIGRAPHIC RANGES. — Upper Pliensbachian of Middle and High Atlas of Morocco .

DESCRIPTION (in collaboration with S. Boivin) Cerioid massive, lamellar or ramose colony. Subcircular to polygonal corallites. The septal apparatus is composed of a major septum, one to four well-developed septa (S1) and a few minor septa (S2). Major septum is highly dominant in length and thickness, straight, compact, ornamented by auriculae on the inner margin of septum. Ordinary, S1 septa also bear auriculae. Auriculae occur in periodic intervals, and are sub-circular in transverse section. In longitudinal section (perpendicular to the septum plan), auriculae are shaped like a horizontally elongated lozenge or a spoon. Inner margin of S1 is strongly enlarged at the level of the auriculae and rounded between the auriculae. Minor septa very short, compact, rounded, and mostly not discernible in the wall. Inner margins of the minor septa with sharp granules that alternate with auriculae. Thin, concave (in distal view) tabulae can be linked to auriculae. Vestiges of microstructure have been observed: straight axes parallel to the wall or divergent with an angle of 10 to 20° appear in longitudinal section. In transverse section we observed black spots in the middle of the wall surrounding the calices. Many heterogeneously distributed intercalicular canals have been observed. These canals are restricted to some parts of the colonies. One single corallite can be connected to until four canals, and sometimes two corallites can be connected by two different canals. Their origin is still unknown. The hypothesis of an association between Hispaniastraea and non-corals organisms is considered. Great diameter of the lumen: 0.47 to 0.89 mm – Small diameter of the lumen: 0.35 to 0.78 mm – Thickness of the wall: 0.09 to 0.72mm – Distance between calices centers: 0.27 to 1.18 mm – Length of major septa: 0.14 to 0.36 mm – Thickness of major septa: 0.03 to 0.21 mm – Number of apparent septa: 3 to 8.

SIMILARITIES AND DIFFERENCES

This species differs from Hispaniastraea murciana Turnšek & Geyer, 1975 by the presence of 1 to 3 S1 septa (there is always one single major septum in H. murciana ), and smaller auriculae (the inner space is shared by the auriculae of the different S1 septa).

Figures

FIG. 30. — Hispaniastraea ousriorum Boivin, Vasseur, Lathuilière, Lazăr, Durlet, Martindale, El Hmidi & Martini, 2019: A, specimen CPUN CDAm1; B, specimen CPUN AM16188-5; C, transverse polished section of the specimen CPUN AM16160-3; D, distal view of the calicular surface of the specimen CPUN AM16188-5; E, transverse thin section of the specimen CPUN CDAm1. Scale bars: A, 5 mm; B, 1 cm; C, 2 mm; D, E, 4 mm.