Lituites procerus Remelé, 1890

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 : 69-72

Lituites procerus Remelé, 1890

Figs 47–49 , Tables 9–10

Lituites procerus Remelé, 1890: 57 , pl. 6 fig. 1.

non Lituites procerus – Foerste 1932: 166, text-fig. 7.

Diagnosis

Species of the genus Lituites with a coiled conch 24–30 mm in diameter; coiling tight or almost tight, 2.5–3 volutions; whorl expansion rate 2.10–2.50. Uncoiled part straight or slightly curved, juvenile expansion angle of up to 5°. Shell surface with widely spaced ribs or annuli and prominent, widely spaced lirae. Ornament elements biconvex or concavo-convex in the coiled part, and concavo-convex in the backcoiled part; ventral sinus deep and rounded, with ventral band (after Balashov 1953, emended).

Type material

Lectotype

Not available for study, designated by Balashov (1953); illustrated by Remelé (1890: pl. 6 fig. 1) and reproduced here in Fig. 47D . It is from Drewin near Neustrelitz (Mecklenburg-Vorpommern, Germany), Upper Grey Orthoceratite Limestone erratics from Pleistocene gravel (late Darriwilian, Middle Ordovician).

Material examined

GERMANY • 1 spec.; Brandenburg, Hohensaaten; Ordovician, Upper Grey Orthoceratite Limestone; Neben and Krueger Coll.; MB.C.30546 • 1 spec.; Brandenburg, Niederfinow; Ordovician, Upper Grey Orthoceratite Limestone; MB.C.2498 • 1 spec.; Brandenburg, Oderberg; Ordovician, Upper Grey Orthoceratite Limestone; Krueger Coll.; MB.C.30547 .

Description

Specimen MB.C.2498 ( Fig. 47C ) consists of a nearly complete coiled part (dm = 30 mm; 2.5 essentially tight, barely detached volutions; Fig. 48F–J ) and a short part of the backcoiled part (length = 15 mm; wh = 9.8 mm; EA <1°). The ornament is produced by ribs (up to 3.5 mm apart) and lirae (up to 0.5 mm apart). The spacing of ribs and lirae increases gradually and regularly during ontogeny. Their ventral sinus is deep and rounded. In the coiled part of the conch, the ornament elements are biconvex; in the backcoiled part, they are concavo-convex and form a shallow lateral sinus.

Specimen MB.C.30546 ( Fig. 47B ) is a part and counterpart of the coiled part (dm = 25 mm; 1.5 nearly tight, slightly detached volutions;) and a short part of the backcoiled part (length = 28 mm; wh = 10 mm; EA ~ 1.5°). The ornament has coarse annuli, which are less than 1 mm in distance in the coiled part and towards backcoiled part of the specimen they are broad and flat and 4 mm apart. The spacing of annuli increases gradually and regularly during ontogeny. Lirae are not visible. The CLR is between 0.53 and 0.79, without an ontogenetic trend.

Specimen MB.C.30547 ( Fig. 47A ) consists of the nearly complete coiled part (dm = 33 mm; 2.5 tightly coiled volutions; Fig. 48A–E ) and a short part of the backcoiled part (length = 33 mm; wh = 13 mm; EA ~5°). The ornament has coarse annuli (1–2 mm apart), lirae are not visible. The phragmocone chambers are variable in length (CLR between 0.24 and 0.58), without an ontogenetic trend ( Fig. 49 ).

Remarks

Lituites procerus is most similar to L. lituus , because it is tightly coiled with conch diameters of up to 30 mm; however, the uncoiled part in L. lituus is moderately curved with a greater expansion angle (5°–8°). Lituites clavis sp. nov. is also tightly coiled but its conch diameter is larger (34 mm) and the uncoiled conch part is moderately curved.

The variation of Lituites procerus concerns mainly the expansion angle at the beginning of the uncoiled stage; it is lower in specimens MB.C.2498 and MB.C.30546 but higher in the specimen figured by Remelé (1890) and specimen MB.C.30547. Furthermore, the latter specimen has narrower lirae at the end of the uncoiled part. Specimen MB.C.2498 is also unique due to the presence of biconvex ribs in the coiled part of the conch.

The late Darriwilian specimen figured by Balashov (1953: pl. 14 fig. 2) from northern Estonia has coarse annuli in the coiled and uncoiled part of the conch and the backcoiled part is rather strongly curved; the specimen is thus here attributed to L. lituus .

Geographic and stratigraphic occurrence

Northern Germany, Upper Grey Orthoceratite Limestone erratics from Pleistocene gravel (late Darriwilian, Middle Ordovician).

Figures

Fig. 47. Lituites procerus Remelé, 1890 from the Upper Grey Orthoceratite Limestone. A. Specimen MB.C.30547 (Krueger Coll.) from Oderberg (Brandenburg). B. Specimen MB.C.30546 (Neben & Krueger Coll.) from Hohensaaten (Brandenburg). C. Specimen MB.C.2498 from Niederfinow (Brandenburg). D. Reproduction of the illustration by Remelé (1890: pl. 6 fig. 1). Scale bar units = 1 mm.

Fig. 48. Lituites procerus Remelé, 1890. A. Outline of coiled conch part of specimen MB.C.30547. B–E. Conch proportions and coiling rates of specimen MB.C.30547. F. Outline of coiled conch part of specimen MB.C.2498. G–J. Conch proportions and coiling rates of specimen MB.C.2498. Scale bar units = 1 mm.

Fig. 49. Lituites procerus Remelé, 1890, chamber length/whorl height of specimen MB.C.30547 (Krueger Coll.) from Oderberg (Brandenburg). A. Empirical data. B. Three data point averaged.