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 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.