Cycloplectoceras hinlopense Kröger & Pohle 2021, sp. nov.
Cycloplectoceras hinlopense sp. nov. urn:lsid:zoobank.org:act: 17CC19A8-797C-4718-AE09-C6DEEF037258 Fig. 41C–D Diagnosis Strongly ribbed Cycloplectoceras with rapidly enlarging conch with WER of ca 3.7 and LER of ca 2, with adult size> 30 mm. Etymology From Hinlopen Strait, referring to the type...
| Published in: | Smart Energy |
|---|---|
| Main Authors: | , |
| Format: | Other/Unknown Material |
| Language: | unknown |
| Published: |
2021
|
| Subjects: | |
| Online Access: | https://zenodo.org/record/5793580 https://doi.org/10.5281/zenodo.5793580 |
| Summary: | Cycloplectoceras hinlopense sp. nov. urn:lsid:zoobank.org:act: 17CC19A8-797C-4718-AE09-C6DEEF037258 Fig. 41C–D Diagnosis Strongly ribbed Cycloplectoceras with rapidly enlarging conch with WER of ca 3.7 and LER of ca 2, with adult size> 30 mm. Etymology From Hinlopen Strait, referring to the type region of this species. Type material Holotype Specimen FMNH-P30327; by monotypy. Type locality and horizon From Profilstranda section, Ny Friesland, Svalbard, bed PO 131, 128 m above base of Olenidsletta Member, Blackhillsian, Floian. Description Specimen FMNH-P30327 is a fragment of a phragmocone consisting of ca two whorls with a total diameter of 26 mm. The conch grows with a WER of 3.66 and a LER of 2. The whorl is 13 mm wide and high at a conch diameter of 26 mm and is slightly flattened on the lateral flanks and venter; a 0.3 mm deep imprint zone is present at the dorsum. The conch is strongly annulated with ribs than run obliquely transverse across the flanks and forming a deep and broad ventral lobe. Prominent growth lines or striae are present, ca 8 per one millimetre, and are parallel to the ribs. The siphuncular perforation has a diameter of 1.4 mm and is positioned at a distance of 1.3 mm from the venter (rSP = 0.1). The septal spacing is relatively narrow; where the conch is 22 mm in diameter the sutures have a distance of 2 mm apart over the venter. Remarks This specimen is assigned to Cycloplectoceras because it is a ribbed tarphycerid with rapidly enlarging whorls, both in whorl height and in whorl width. The conch cross section is nearly circular, similar as in known species of Cycloplectoceras. Pionoceras Ulrich et al., 1942 is another annulated tarphycerid with high WER and rapid growth of the whorl width. Pionoceras, however, differs in having broadly subtrapezoidal whorl cross sections and a very broad venter. The fragment described above is, however, relatively small, and ontogenetic growth changes are frequent among tarphycerid species, and especially among species of Pionoceras. It is ... |
|---|