The nautiloids from the Early Carboniferous Dalle à Merocanites of Timimoun, western Algeria
Author
Korn, Dieter
286CA4F3-7EBC-4AEF-A66A-B2508D001367
Museum für Naturkunde, Leibniz Institut for Research on Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, Germany. State Key Laboratory of Biogeology & Environmental Geology, School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Wuhan, China. Dechant-Fein-Strasse 22, 51375 Leverkusen, Germany.
dieter.korn@mfn.berlin
Author
Miao, Luyi
2171F5FC-45B5-452B-A134-CD1308B3A085
miaoluyi@cug.edu.cn
Author
Bockwinkel, Jürgen
F7FE7EEA-B678-4FEE-879C-8C429F66BF3A
jbockwinkel@t-online.de
text
European Journal of Taxonomy
2022
2022-01-28
789
104
129
http://dx.doi.org/10.5852/ejt.2022.789.1635
journal article
20812
10.5852/ejt.2022.789.1635
338a1525-2dbe-4c49-99b9-737a0b17334d
2118-9773
5965355
A475F919-D925-457E-B007-3FE2B55659A3
Rineceras multituberculatum
sp. nov.
urn:lsid:zoobank.org:act:
B0489DAA-C8AB-4809-92D3-6F3120899BBD
Fig. 8
;
Table 4
Etymology
After the Latin ‘
multi
’, meaning ‘many’, and ‘
tuberculum
’, meaning ‘tubercle’ and referring to the shell ornament.
Table 4.
Conch dimensions (in mm) and ratios of
Rineceras multituberculatum
sp. nov.
| Specimen |
dm |
ww |
wh |
uw |
ah |
ww/dm |
ww/wh |
uw/dm |
WER |
IZW
|
| MB.C.30381 |
21.3 |
9.9 |
6.9 |
9.7 |
6.2 |
0.47 |
1.45 |
0.45 |
1.99 |
0.09 |
Type material
Holotype
ALGERIA
•
Gourara
,
Sebkha de Timimoun
14.5 km
west-southwest of Timimoun
; “
Dalle à
Merocanites
” (
Tournaisian-Viséan boundary interval
); illustrated in
Fig. 8
;
MB.C.30381
.
Diagnosis
Species of
Rineceras
with weakly depressed, rounded-trapezoidal whorl profile (ww/wh ~ 1.45), venter slightly flattened, ventrolateral shoulder broadly rounded. Whorls slightly embracing. Ornament with about 25 spiral lines on the flank and the venter.
Description
Holotype
MB.C.30381 has a conch diameter of
21 mm
(
Fig. 8
), with a depressed, rounded-trapezoidal whorl profile (ww/wh = 1.44) with a flattened venter and a broadly rounded ventrolateral shoulder. The whorl embraces the preceding only a very little. The well-preserved ornament consists of about 20 (from umbilicus to midventer) coarse spiral lines with a coarse granulation at the points of intersection with the growth lines. The spiral lines are equally coarse on the flanks and the venter.
Remarks
With its rounded trapezoidal whorl profile,
Rineceras multituberculatum
sp. nov.
differs from species such as
R. propinquum
(
de Koninck, 1880
)
,
R. carinatum
(von Eichwald, 1857)
,
R. alapaevskense
and
R. ohioense
, which are loosely coiled and have either a rounded triangular, or an oval whorl profile (
Koninck 1880
;
Miller & Garner 1953
;
Shimansky 1967
). In this respect,
R. multituberculatum
sp. nov.
and
R. meekianum
(
Winchell, 1862
)
are similar (
Winchell 1862
), but have only weak spiral lines on the venter.
Rineceras canaliculatum
(von Eichwald, 1857)
has a whorl profile similar to
R. multituberculatum
sp. nov.
, but much coarser spiral lines on the flank (
Shimansky 1967
).