Taxonomy and ontogeny of the Lituitida (Cephalopoda) from Orthoceratite Limestone erratics (Middle Ordovician)
Author
Aubrechtová, Martina
CAF4231-8787-4051-8D76-F983332517EE
Institute of Geology and Palaeontology, Faculty of Science, Charles University Prague, Albertov 6, Prague, 12843, Czech Republic. & Institute of Geology, Czech Academy of Sciences, Rozvojová 269, Prague, 16500, Czech Republic.
aubrech1@natur.cuni.cz,aubrechtova@gli.cas.cz
Author
Korn, Dieter
286CA4F3-7EBC-4AEF-A66A-B2508D001367
Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, Germany.
dieter.korn@mfn.berlin
text
European Journal of Taxonomy
2022
2022-03-08
799
1
1
108
http://dx.doi.org/10.5852/ejt.2022.799.1681
journal article
20271
10.5852/ejt.2022.799.1681
f53d5465-7162-45d6-892b-dfc0b8d99789
2118-9773
6341270
F52DBAB0-38C7-400F-9BA1-E2D8E6B19E7E
Holmiceras havelense
sp. nov.
urn:lsid:zoobank.org:act:
C92771A7-17B5-4838-8B38-62884C9AAA5C
Fig. 29
,
Table 8
Lituites
aff.
praecurrens
–
Neben & Krueger 1971
: pl. 21 figs 2–3.
Fig. 29.
Holmiceras havelense
sp. nov.
from the Upper Red Orthoceratite Limestone.
A
. Holotype MB.C.30526 (Neben & Krueger Coll.) from Werder (Brandenburg); previously figured by
Neben & Krueger (1971
: pl. 21 figs 2–3).
B
. Lirae of holotype MB.C.30526 at wh = 14 mm. Scale bar units = 1 mm.
Table 8.
Conch measurements (in mm), ratios and rates of coiled conch parts of
Holmiceras
Hyatt, 1894
.
| taxon |
catalogue nr |
dm |
wh |
uw |
ww |
WERdm |
WERah |
UWI |
WWI
|
|
H. havelense
|
MB.C.
30526
|
20.6 |
7.8 |
7.8 |
– |
2.85 |
2.59 |
0.38 |
– |
Diagnosis
Species of the genus
Holmiceras
with coiled part
21 mm
in diameter; uncoiled part nearly straight; expansion angle 7°. Shell surface with growth lines and fine, irregularly spaced lirae.
Etymology
From the river Havel, which flows through the
type
region.
Type material
Holotype
GERMANY
•
Brandenburg
,
Werder
(Potsdam);
Ordovician
,
Upper Red Orthoceratite Limestone
;
Neben
and
Krueger
Coll.; previously illustrated by
Neben & Krueger (1971
: pl. 21 figs 2–3), reillustrated here in
Fig. 29A
;
MB.C.30526
.
Description
Holotype
MB.C.30526 (
Fig. 29A
) consists of the coiled part (dm =
21 mm
; coiling probably loose, the end of the last volution nearly in contact with the preceding whorl; WER
ah
= 2.60; WER
dm
= 2.90) and a short part of the almost straight uncoiled part (length =
29 mm
; wh =
14 mm
; EA ~ 7°). The delicate shell ornament consists of growth lines and thin lirae, some of which are more raised than others; any prominent annulation is absent. The lirae are laterally oblique, sloping towards the dorsal side; the ventral sinus is deep and rounded and the dorsal projection is flat (
Fig. 29B
). The CLR is between 0.20 and 0.25.
Remarks
Specimen MB.C.30526 fits in the diagnosis of
Holmiceras
but differs from all species of this genus in the more delicate ornament and a much smaller expansion angle of the uncoiled conch part (7° in the new species but 20° in the others).
Geographic and stratigraphic occurrence
The
holotype
is from Werder (
Brandenburg
,
Germany
) and comes from erratics (Aseri Regional Stage, middle Darriwilian, Middle Ordovician) in Pleistocene gravel.