Montlivaltia fragilis (Fromentel & Ferry, 1866)

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

Montlivaltia fragilis (Fromentel & Ferry, 1866)

( Fig. 63 )

Montlivaultia [sic] fragilis Fromentel & Ferry, 1866: 139 , pl. 24, fig. 4. — Alloiteau 1956b n °119.

Montlivaltia cf. fragilis – Beauvais 1986: 225; 1988: 1091.

Proleptophyllia fragilis – Vasseur 2018: 295-296, fig. 3.77.

TYPE MATERIAL. — Lectotype MNHN.F. M03716 , Fromentel & Ferry 1866: 139, pl. 24, fig. 4, subsequent designation following the abusive stipulation of the existence of a holotype by Alloiteau (1956b), n°119 ( ICZN 1999 : art.74.6.). TYPE HORIZON. — Pliensbachian . TYPE LOCALITY. — May-sur-Orne, France. STUDIED SAMPLE. — Lectotype MNHN.F. M03716 . GEOGRAPHIC AND STRATIGRAPHIC RANGES. — Pliensbachian of May-sur-Orne ( Calvados , France).

DESCRIPTION

Solitary, subconical corallum. Radial elements are exsert, thin, subcompact, straight costosepta with trabecular, montlivaltid microstructure made of spaced carinae. No columella but a large and quite deep circular fossa. Endotheca made of tabular dissepiments at the periphery. We observed some vestiges of an epicostal epitheca s.l. that covered the external part of the corallum. Calicular diameter: 36 mm – Septal density:3 to 4 per 2 mm.

SIMILARITIES AND DIFFERENCES

Even if the species is based on one single specimen, it is distinct among species of the genus Montlivaltia because of the delicacy of septa and the large space between them and between carinae in one single septum.

Figures

FIG. 63. — Montlivaltia fragilis (Fromentel & Ferry, 1866): A, lateral view of the holotype MNHN.F.M03716; B, lateral view of the holotype MNHN.F.M03716; C, detail of the septal pennular ornamentation of the holotype MNHN.F.M03716; D, detail in lateral distal peripheral view of the septal apparatus of the holotype MNHN.F.M03716; E, detail in lateral peripheral view of the holotype MNHN.F.M03716; Scale bars: A, B, 2 cm; C, 1 mm; D, 1 cm; E, 2 mm.