Actinoseris d’Orbigny, 1849

Löser, Hannes, 2013, Revision of the family Asteroseriidae (Anthozoa, Scleractinia, Cretaceous), Geodiversitas 35 (1), pp. 21-29 : 23-24

Genus Actinoseris d’Orbigny, 1849

TYPE SPECIES. — Actinoseris cenomaniensis d’Orbigny, 1849 , by monotypy. The type species is valid as combined description of genus and species.

RANGE. — Hauterivian to Cenomanian.

DIAGNOSIS. — Solitary patellate corallum. Calicular outline circular. Septa compact. Microstructure of septa unknown. Septa in cross section externally slightly thicker, and slightly thinner towards the centre of the calice.Septal maximum thickness 250 µm. Symmetry of septa radial and regularly hexameral. Cycles of septa regular. Septal cycles differ in length, almost not in thickness. First three septal cycles extended to the centre of the calice, later cycles are shorter. Septa of younger cycles often and regularly connected to septa of preceeding ones. Septal upper border smooth (probably due to preservation), lateral face with numerous fine thorns, inner margin unknown. Pali or paliform lobes absent. Costae present. Costae ornamented with fine granules on their surface. Synapticulae present, irregularly distributed. Columella composed of a group of isolated granules. Endotheca unknown. Wall present, compact, structure unknown.

REMARKS

For the type species, only the complete type specimen and thin sections of topotypical specimens were available. The structure of the synapticulae and the endotheca could not be observed because no longitudinal thin sections could be prepared and because the type specimen is eroded and barely shows ornamentation. Species other than the type species show a regular dentation of the septal upper margin and vertical lines of granulae on the septal lateral face corresponding to the dentations. The existence of fulturae is possible, but could not be proven with the available material; they are reported by Alloiteau (1957: 339). The endotheca is absent in species other than the type species, although Alloiteau (1957:339) claimed it existed. Alloiteau obviously had more material on hand, but it could not be found at the MNHN. The type locality has been inaccessible for a long time and does not allow re-collection.

Actinoseris cannot be assigned to the Funginellidae as formerly proposed. Funginella d’Orbigny, 1849 was long considered congeneric with the genera of the Asteroseriidae assuming that F. neocomiensis d’Orbigny, 1850 is the type species (for instance Beauvais 1982: II, 117). Hence, the type species is Cyclolites haueri Michelin, 1847 , as designated by Wells (1936). The genus cannot be assigned to the Siderastraeidae because of the comparably lower density of ornamentation of the lateral faces of septa and lower number of synapticulae.