Axosmilia amellagouensis, Vasseur & Lathuilière, 2021

Vasseur, Raphaël & Lathuilière, Bernard, 2021, Pliensbachian corals from the Western Tethys, Geodiversitas 43 (22), pp. 1187-1291 : 1199

Axosmilia amellagouensis n. sp.

( Fig. 6 )

urn:lsid:zoobank.org:act:C15279BE-8D58-4334-A6B9-CA2FC354803D

Axosmilia sp. 1 – Vasseur 2018: 137-138, fig. 3.13.

TYPE MATERIAL. — Holotype CPUN AM16164bis2.

ETYMOLOGY. — From the type locality Amellago in the High Atlas of Morocco.

TYPE HORIZON. — Pliensbachian . TYPE LOCALITY. — Amellagou, 31°56’58”N, 5°2’31”W, Morocco. STUDIED SAMPLE. — CPUN AM16164bis2. GEOGRAPHIC AND STRATIGRAPHIC RANGES. — Pliensbachian of Amellagou ( High Atlas of Morocco).

DESCRIPTION

Solitary, subcylindrical corallum with successive constrictions and expansions (probably rejuvenescences). Radial elements are exsert, straight or slightly wavy, free costosepta with much reduced costal part. The inner edge of major septa is rhopaloid. Lateral faces are ornamented with irregular small granules. An elongated columella of trabecular structure appears at the middle of the calice, defining a bilateral symmetry. Endotheca made of dissepiments that look vesicular. Parathecal wall. An epitheca s.l. wraps the corallite.

Calicular diameter: 15 mm – Calicular height: 45 mm – Number of septa:>140 – Septal density: approximately 7-8 per 2 mm.

SIMILARITIES AND DIFFERENCES

The exsert septa make this taxon closer to the genus Pleurosmilia that we merge here with Axosmilia . If they should be splitted again in the future, it would then likely correspond to this first genus. If the rhopaloid character of inner edge of septa and the trabecular structure of the columella reveals to be constant in a more extensive sampling a new genus could be justified.

Compared to all other Jurassic species of Axosmilia Milne Edwards, 1848 , Pleurosmilia Fromentel, 1856 , Axiphyllum Quenstedt, 1880 and Bathmosmilia Alloiteau, 1958 the ratio between dimensions of calice and number of septa is unique. The thickness of major septa is also especially low in this new species.

Despite the fact that only one single sample has been known up until now, this taxon resembles nothing else in the Pliensbachian nor in the other known Jurassic Axosmiliidae and corresponds undoubtedly to a new species.

Figures

FIG. 6. — Axosmilia amellagouensisn. sp.:A, lateral view of the specimen CPUN AM16164bis2;B, detail of the axial structure of the specimen CPUN AM16164bis2; C, transverse section in the specimen CPUN AM16164bis2. Scale bars: A, 1 cm; B, 2 mm; C, 4 mm.