Angelinoceras sp.

Aubrechtová, Martina & Korn, Dieter, 2022, Taxonomy and ontogeny of the Lituitida (Cephalopoda) from Orthoceratite Limestone erratics (Middle Ordovician), European Journal of Taxonomy 799 (1), pp. 1-108 : 43-44

Angelinoceras sp.

Fig. 28B , Table 7

Material examined

GERMANY • 1 spec.; Brandenburg, Oderberg; Ordovician, Upper Red Orthoceratite Limestone; Krueger Coll.; MB.C.29658 .

Description

Specimen MB.C.29658 ( Fig. 28B ) consists of the coiled part (coiling tight; 33 mm diameter; WWI = 0.66; WER dm = 2.20 and WER ah = 2.30) of a conch. The shell surface is only locally and indistinctly preserved. Narrow annuli are separated by very thin lirae and both form a deep ventral sinus, which is delineated by paired longitudinal grooves.

Remarks

The specimen represents an Angelinoceras as indicated by its conch ratios and type of ornament. The specimen differs from A. latum in the smaller, tightly coiled conch with a slightly lower whorl expansion rate. The incomplete preservation of the last whorl and of the early uncoiled part makes it difficult to decide whether the specimen should be assigned to a new species or whether it only reflects morphological variation within A. latum .

Figures

Fig. 28. Angelinoceras Hyatt, 1894 from the Upper Red Orthoceratite Limestone. A. Angelinoceras latum (Angelin, 1880), specimen MB.C.11682 (Remelé 1878 Coll.) from Eberswalde (Brandenburg); lateral view.B. Angelinoceras sp., specimen MB.C.29658 (Krueger Coll.) from Oderberg (Brandenburg). Scale bar units = 1 mm.