Phacelostylophyllum mg. arbustulum, 1972

Vasseur, Raphaël & Lathuilière, Bernard, 2021, Pliensbachian corals from the Western Tethys, Geodiversitas 43 (22), pp. 1187-1291 : 1258

Phacelostylophyllum mg. arbustulum n. sp.

( Fig. 49 )

urn:lsid:zoobank.org:act:329A0F5D-31AE-41EA-9475-2E4641789CDE

Phacelostylophyllum sp. 2 – Vasseur 2018: 289-290, fig. 3.75.

TYPE MATERIAL. — Holotype:CPUNPFPyr13; paratype:CPUNPFPyr9. S TUDIED SAMPLES. — Two specimens: CPUN PFPyr9, PFPyr13. ETYMOLOGY. — Refers to the true bushing aspect of this very developed phaceloid form. TYPE HORIZON. — Pliensbachian . TYPE LOCALITY. — Estivère pass and surrounding areas (Pyrenees, France). GEOGRAPHIC AND STRATIGRAPHIC RANGES. — Pliensbachian of the Estivère pass and surrounding areas ( Pyrenees , France) .

DESCRIPTION

Phaceloid colony with cylindrical corallites multiplying by extratentacular lateral budding.Radial elements are subcompact, free, straight or wavy septa, organized in 2 distinct size orders. Microstructure typically stylophyllid: septa are made of septal spines linked together by thickening deposits and generally dissociated at the distal and inner edges. Septa show a rhopaloid aspect in transverse section when a septal spine occur in its very inner part. The dissociation of the septal spines along the inner edge sometimes produces a papillose columella.Endotheca made of tabular and vesicular dissepiments. Wall present, apparently parathecal. An epitheca s.l. seems to wrap the corallites.

Calicular diameter: 3 to 7 mm – Number of septa: 28 to 45 – Septal density: 4 to 5 for 2 mm.

SIMILARITIES AND DIFFERENCES

Differs from Phacelostylophyllum martini (Fromentel, 1860) by the reduced size of the calices and the mode of budding.The new species has dimensions overlapping with P.irregularis (Duncan, 1867) . However the Hettangian species of Duncan has a very weak colonial development and a different mode of budding. From other species of the genus, P.arbustulum n. sp. is distinctive by its bushlike shape and by low values of diameter for such a number of septa (30-45). Phacelostylophyllum romerloana ( Volz, 1896) and P. pygmaeum ( Frech, 1890) have much less septa.

Figures

FIG. 49. — Phacelostylophyllum mg. arbustulum n. sp.: A, distal view of specimen CPUN PFPyr13; B, longitudinal oblique section of two corallites of the specimen CPUN PFPyr13; C, transverse section of two corallites of the specimen CPUN PFPyr13; D, transverse thin section in specimen CPUN PFPyr13. Scale bars: A, 5 cm; B, C, D, 5 mm.