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
Thylacodes
? sp.
Figs 27
K–M
Material.
Specimen
MGUH
33191 is a fragmentary
2.4 mm
wide external mould.
Occurrence.
Thylacodes
? sp. was collected from the top of the Maastrichtian Tor Formation at Holtug Quarry, Stevns Klint.
Description.
Shell low turbiniform, sinistral with flattened apex seemingly attached to a slender bryozoan branch. Protoconch heterostrophic, consisting of two whorls on which no microsculpture can be observed. Teleoconch whorls expanding slowly, flattened on adapical side, becoming more convex on lateral and abapical side. Adapical side of whorls with strong transverse ribs curving from the adapical suture and backwards into an initially indistinct, but progressively deeper sinus situated halfway between sutures; transverse ribs continue forward and down to the periphery of the last whorl, where they are replaced rather abruptly by seven moderately coarse spiral ribs. Transverse rib number per half-whorl approximating 15 on third whorl.
Remarks.
Thylacodes
? sp. differs from
T. contendis
n. sp.
described above by the sinistral coiling and a coarser transverse ribbing. This may though just reflect ecophenetic differences within the species; especially as only a single specimen is known of the present taxon.