Palaeonummulites trinitatensis ( Nuttall, 1928 )

Torres-Silva, Ana. I., Eder, Wolfgang, Hohenegger, Johann & Briguglio, Antonino, 2018, Morphometric analysis of Eocene nummulitids in western and central Cuba: taxonomy, biostratigraphy and evolutionary trends, Journal of Systematic Palaeontology 17 (7), pp. 557-595 : 580-582

Palaeonummulites trinitatensis ( Nuttall, 1928)

( Fig. 17H, I )

1928 Operculina trinitatensis Nuttall : 102, pl. 8, figs 10, 11.

1941 Operculinoides trinitatensis (Nuttall) ; Vaughan & Cole: 47, pl. 10, fig. 12, pl. 13, figs 4–14.

1941 Operculinoides kugleri (Nuttall) ; Vaughan & Cole: 18, pl. 10, figs 3–5, 7, 8, pl. 13, figs 1, 2.

1975 Operculinoides spiralis (Nuttall) ; Caudri: 542, pl. 1, fig. 20, pl. 8, fig. 13.

1975 Operculinoides trinitatensis (Nuttall) ; Caudri: 541, pl. 1, figs 10, 16, pl. 8, figs 14, 15.

Material. Four megalospheric specimens in equatorial section from Loma Candelaria (98LC-1).

Description.

External features. The test is planispiral, involute, laterally slightly compressed. No trace of septal sutures and ornamentation is visible due to poor preservation of the individuals studied here.

Internal features. Megalospheric generation with spherical proloculus (mean diameter = 0.1 mm) followed by a reniform deuteroloculus and a moderately tightly coiled spiral with commonly three whorls. Rapid increase in height of the last spiral, with chamber height roughly 3 times greater than chamber length. Operculine primary septa with strong backbend angle gently tapered towards inner ends.

Characters and attributes for Palaeonummulites trinitatensis and comparisons with Nummulites striatoreticulatus , Operculinoides floridensis (tightly coiled), O. floridensis (loosely coiled) and O. soldadensis are given in Table 5 .

Occurrence. Late middle Eocene to late Eocene NP 16/ 17, Loma Candela Formation.

Remarks. Palaeonummulites tinitantensis is not abundant in the Eocene of western and central Cuba but is sporadically present at the Loma Candelaria locality. Cole (1961) admitted that it is difficult to distinguish between P. trinitatensis and P. willcoxi ; the latter is the most widely recognized nummulitid in the Caribbean province and is absent at the studied localities. The lack of an easily recognizable holotype has led to many different morphotypes being described as Nummulites or Operculinoides willcoxi . We regard the specimen illustrated by Barker (1939) as the most similar to the original description, whereas specimens illustrated in Cole (1941) conform more closely to the moderately tightly coiled O. floridensis .

Stratigraphical and geographical distribution. Late Eocene (Priabonian); Cuba, Trinidad.

Figures

Figure 17. A–G, Operculinoides soldadensis Vaughan & Cole; A, Loma El Santo, CA-215-871; B, Loma Candelaria, 98LC-1-669; C– F, Norona; C, NOR-UN 24; D–F, NOR-UN 15/14; G, holotype, Trinidad. H, I, Palaeonummulites trinitatensis (Nutall); H, Loma Candelaria, 98LC-1ICT3; I, holotype of Operculinoides kugleri Vaughan & Cole, Trinidad. J, Operculinoides ocalanus (Cushman), Loma Jabaco, CA-4-724. A–D, G–J, A forms in equatorial section; E, A form in axial section; F, external view.