Gastropods from the Cretaceous-Palaeogene boundary in Denmark
Author
Hansen, Thomas
text
Zootaxa
2019
2019-08-12
4654
1
1
196
journal article
26049
10.11646/zootaxa.4654.1.1
9ce1d103-9234-4fbe-9544-f1c294bb8783
1175-5326
3365803
CFD82CC0-3110-472E-972B-7ADC0C523A04
Ringicula
sp.
Figs 35
L–P
Material.
MGUH
33314,
MGUH
33315,
MGUH
33316, and an additional specimen sitting together with
MGUH
33315.
Occurrence.
The lower Danian ‘dead layer’ exposed in the Dania Quarry, Northern Jutland.
Description.
Protoconch apparently conical in outline,
0.8 mm
wide with smooth, convex whorls separated by deep suture.
Teleoconch low spired, rotund with flattened, adpressed spire whorls; whorls nearly four times as wide as high. Last whorl evenly convex all the way to anterior canal, taking up more than 80 % of shell height. Aperture narrow, outer lip strengthened by strong varix reaching from anterior canal to adapical suture of transition between last whorl and penultimate whorl. Outer lip carrying five stronger, elongated teeth on abapical part, succeeded adapically by several more, but very weak teeth fading out completely adapically. Inner lip with moderately wide callus and two sinuses separated by a strong and furrowed ridge. Adapical parietal region carrying strong but low and ridged transverse thickening of the shell.
Teleoconch sculpture consisting of around 20 moderately weak spiral grooves, which continue onto the varix.
Measurements.
Most complete specimen
MGUH
33314 is 6.0 mm wide and more than
6.9 mm
high, but lacking anterior canal and protoconch apex. It consists of the final protoconch whorl and 3 ½ teleoconch whorls.
Remarks.
This species differs from the Danian
Ringicula pinguis
Glibert, 1973
from
Belgium
by the much more rotund outline, adpressed whorls and furrowed lower ridge on the inner lip. It differs from the Campanian
R. abundanta
Kiel & Bandel, 2001a
and
R. multidentata
Kiel & Bandel, 2001a
from
Spain
by the rotund shape and from the latter also by a different tooth pattern on the outer lip. It differs from the Palaeocene
R. erratica
Roedel, 1937
from Northern Europe by its lower spire and more flattened spire whorls.