Morphometric analysis of Eocene nummulitids in western and central Cuba: taxonomy, biostratigraphy and evolutionary trends
Author
Torres-Silva, Ana. I.
Department of Palaeontology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria;
Author
Eder, Wolfgang
Department of Palaeontology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria;
Author
Hohenegger, Johann
Department of Palaeontology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria;
Author
Briguglio, Antonino
Dipartimento di Scienze della, Terra dell’Ambiente e della Vita, Universita ́ degli Studi di Genova, Corso Europa, 26, I- 16132 Genova, Italy
text
Journal of Systematic Palaeontology
2018
2018-04-13
17
7
557
595
http://dx.doi.org/10.1080/14772019.2018.1446462
journal article
10.1080/14772019.2018.1446462
1478-0941
PMC6474738
31057335
10883523
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
.
Table 4.
Characters and attributes (means and standard deviations, SD, in mm) for
Palaeoummulites
and comparisons with
Nummulites
and
Operculinoides
.
Symbol key: +, differences with <5% error probability; 0, no significant differences; –, strong negative differences with <1% error probability.
Palaeonummulites
|
Mean |
SD |
Operculinoides
|
Nummulites
|
First chamber length |
243.3 |
38.59 |
―― |
―― |
Proloculus nominal diameter |
113.0 |
25.84 |
0 |
―― |
Deuteroloculus ratio |
0.888 |
0.1258 |
―― |
0 |
Initial marginal radius |
140.1 |
28.76 |
0 |
―― |
Marginal radius increase |
0.094 |
0.0195 |
0 |
0 |
Spiral chamber height increase |
1.7 |
0.07 |
―― |
―― |
Initial spiral chamber height |
46.5 |
10.02 |
0 |
―― |
Backbend angle |
0.495 |
0.1320 |
0 |
+ |
Initial chamber length |
139.0 |
17.17 |
―― |
―― |
Chamber length increase |
0.028 |
0.0175 |
0 |
0 |
Perimeter ratio |
1.277 |
0.1076 |
0 |
0 |
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.
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
.
Table 5.
Characters and attributes (means and standard deviations, SD, in mm) for
Palaeonummulites trinitatensis
and comparisons with
Nummulites striatoreticulatus
,
Operculinoides floridensis
(tightly coiled),
O. floridensis
(loosely coiled) and
O. soldadensis
.
Symbol key: ++, strong positive differences with <1% error probability; +, differences with <5% error probability; 0, no significant differences; -, negative differences with <5% error probability; ――, strong negative differences with <1% error probability.
P. trinitatensis
|
Mean |
SD |
O. floridensis
(tightly coiled)
|
O. floridensis
(loosely coiled)
|
O. soldadensis
|
N. striatoreticulatus
|
First chamber length |
218.2 |
53.81 |
―― |
―― |
0 |
―― |
Proloculus nominal diameter |
99.0 |
28.91 |
―― |
―― |
0 |
―― |
Deuteroloculus ratio |
0.950 |
0.1376 |
0 |
―― |
- |
0 |
Initial marginal radius |
126.8 |
32.48 |
―― |
―― |
0 |
―― |
Marginal radius increase |
0.099 |
0.0172 |
0 |
―― |
―― |
++ |
Spiral chamber height increase |
1.7 |
0.30 |
―― |
0 |
0 |
―― |
Initial spiral chamber height |
35.5 |
17.71 |
―― |
―― |
0 |
―― |
Backbend angle |
0.445 |
0.1165 |
0 |
- |
―― |
++ |
Initial chamber length |
151.9 |
26.76 |
―― |
―― |
0 |
―― |
Chamber length increase |
0.025 |
0.0149 |
0 |
0 |
―― |
0 |
Perimeter ratio |
1.263 |
0.0859 |
0 |
- |
―― |
+ |
Stratigraphical and geographical distribution.
Late Eocene (Priabonian);
Cuba
,
Trinidad
.