Operculinoides soldadensis Vaughan & Cole 1941

Operculinoides soldadensis Vaughan & Cole, 1941

(Fig.17A–G)

1941 Operculinoides soldadensis Vaughan & Cole: 18, pl. 9, figs 5–8, pl. 10, figs 1, 2.

1947 Nummulites (Operculinoides) floridensis (Vaughan & Cole); de Cizancourt: 517, pl. 25, figs 8–10, 13.

1961 Nummulites floridensis Heilprin; Butterlin: 12, figs 5–6.

1975 Operculinoides soldadensis Vaughan & Cole; Caudri: 537, pl. 1, fig. 11, pl. 8, figs 5–8, 10.

1996 Operculinoides suteri Caudri; Caudri: 1189, pl. 10, fig. 9.

Material. Twenty-five megalospheric specimens in equatorial section, comprising five from Loma Candelaria (98LC-1), four from Loma El Santo (CA-215), one from Loma Jabaco (LM-52) and 15 from Norona (NOR-UN).

Description.

External features. Test planispiral, flattened, last whorl fragile and laterally compressed, involute in the nepionic stage, becoming evolute in the last whorl. The prominent central umbo is surrounded by slightly raised septal sutures.

Internal features. Megalospheric generation with spherical proloculus with a mean diameter of 0.09 mm, followed by reniform deuteroloculus and a loosely coiled spiral with commonly two to three whorls. Rapid increase in height of the last spiral with chamber height roughly 4– 5 times higher than chamber width. Primary operculine septa with strong backbend angle gently tapered towards inner ends and with septal undulations. A diagnostic characteristic are the numerous and narrow chambers.

Characters and attributes (means and standard deviations) for Operculinoides soldadensis and comparisons with Nummulites striatoreticulatus, Palaeonummulites trinitatensis, Operculinoides floridensis (tightly coiled) and O. floridensis (loosely coiled) are given in Table 9.

Occurrences. Middle late Eocene to late Eocene, NP 16/ NP17, upper part of the Loma Candela Formation; late middle Eocene, CNE 13, Arroyo Blanco Formation;?early Oligocene O1/P18 and NP 21 /CP 16, Jabaco Formation.

Remarks. Cole (1958) considered O. soldadensis to be synonymous with O. floridensis; however, our morphometric analysis based on growth-independent and growth-invariant characters clearly distinguished the two species (Table 3): Operculinoides soldadensis shows fewer morphological variations (ecophenotypes) at distinct depositional gradients than O. floridensis.

Stratigraphical and geographic dialstribution. Middle to late Eocene (Lutetian to Priabonian); Cuba Trinidad, Mexico.