Angelinoceras latum (Angelin, 1880)

Figs 26–28, Table 7

Lituites latus Angelin, 1880: 9, pl. 11 figs 1–4.

Lituites Hageni Remelé, 1880: 228, pl. 1 figs 4–5, pl. 3 fig. 3.

Lituites Hageni – Remelé 1890: 19, pl. 1 figs 4–5, pl. 3 fig. 3.

Lituites latus – Jaanusson & Mutvei 1953: 18, fig. 3b.

Angelinoceras latum – Sweet 1958: 132. — Balashov 1962: pl. 7 fig. 2.

Lituites hageni – Neben & Krueger 1971: pl. 21 figs 4–5.

Lituites cf. hageni – Neben & Krueger 1971: pl. 21 fig. 6.

Diagnosis

As for the genus.

Type material

Lectotype

Not re-studied; the specimen figured by Angelin (1880: pl. 11 figs 1–4; illustration reproduced here in Fig. 26), from Vikarbyn (Dalarna, Sweden) and was found in the lower part of the Segerstad Limestone (Upper Red Orthoceratite Limestone, Aseri Regional Stage, middle Darriwilian, Middle Ordovician; designated and re-illustrated by Jaanusson & Mutvei (1953: 18, fig. 3b).

Material examined

GERMANY • 1 spec.; Brandenburg, Vierraden (Schwedt); Ordovician, Upper Grey Orthoceratite Limestone; Krueger 1974 Coll.; MB.C.11687 • 1 spec.; Brandenburg, Eberswalde; Ordovician; MB.C.11681 • 1 spec.; Brandenburg, Eberswalde railway station; Ordovician, Upper Red Orthoceratite Limestone; Remelé 1878 Coll.; MB.C.11682 • 1 spec.; Brandenburg, Heegermühle; Ordovician, Upper Red Orthoceratite Limestone; Kgl. Forstakademie Eberswalde Coll.; MB.C.11683 • 2specs; Brandenburg, Niederfinow; Ordovician, Upper Red Orthoceratite Limestone; MB.C.30523, MB.C.30524 • 1 spec.; Brandenburg, Oderberg; Ordovician, Upper Red Orthoceratite Limestone; Neben Coll.; MB.C.30525 .

POLAND • 1 spec.; Silesia, probably Żory (former Sorau); Ordovician, Upper Red Orthoceratite Limestone; Kirchner Coll.; MB.C.11684 .

Description

The seven specimens are fragments of the last whorl of the coiled part (coiling tight at least in the last whorl; 42–54 mm in diameter; WWI = 0.88–0.94; WER ah = 2.30–2.60; WER dm = 2.60–3.10). Only the specimen MB.C.11682 (Fig. 28A) has a short part of the uncoiled part (27 mm long; 29 mm whorl height) of the conch. The shell ornament consists of narrow annuli (up to 2 mm apart) and fine lirae in between (up to 1 mm apart); a ventral band flanked by ventrolateral ridges is formed on the venter (Fig. 27). Annuli may have pairs of raised lirae on their crests.

Remarks

Three of the seven specimens (MB.C.11681–MB.C.11683; Fig. 27) studied here are syntypes of Lituites hageni from Darriwilian erratics of northern Germany. Rüdiger (1889) and Dzik (1984) suggested that L. hageni is a junior synonym of Angelinoceras latum . This view is followed and supported here because the syntypes of L. hageni differ from the lectotype of A. latum (Fig. 26) only in the larger diameter of their coiled parts. Moreover, the additional specimen MB.C.30525, figured by Neben & Krueger (1971: pl. 21 fig. 6), is even smaller than the lectotype, while closely resembling all other investigated specimens.

Geographic and stratigraphic occurrence

Sweden (in situ) and northern Germany and northern Poland (in erratics within Pleistocene gravels); upper Kunda to Aseri (possibly up to lower Lasnamägi) regional stages (middle to late Darriwilian, Middle Ordovician).