Tornoceras typus (Sandberger & Sandberger, 1851)

Korn, Dieter & Bockwinkel, Jürgen, 2022, The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea), European Journal of Taxonomy 806, pp. 32-51 : 36-38

publication ID

https://doi.org/ 10.5852/ejt.2022.806.1699

publication LSID

lsid:zoobank.org:pub:A2B2A310-8C8C-41B0-B934-1666129B7D90

persistent identifier

https://treatment.plazi.org/id/03DD7E29-FFAE-207E-FE03-F8FD1912FBE9

treatment provided by

Felipe

scientific name

Tornoceras typus (Sandberger & Sandberger, 1851)
status

 

Tornoceras typus (Sandberger & Sandberger, 1851) View in CoL

Fig. 4 View Fig ; Table 1 View Table 1

Goniatites retrorsus var. typus Sandberger & Sandberger, 1851: 109 , pl. 10 fig. 14.

Tornoceras simplex Mut. typus View in CoL – Holzapfel 1895: 98, text-fig. 6, pl. 6 fig. 11, pl. 7 fig. 9. Tornoceras typus View in CoL – Korn 2021b: 149, text-figs 2–5, 6a.

Tornoceras typum View in CoL – Becker 1993: 182, pl. 3 figs 1–2. — Korn & Klug 2002: 156, text-fig. 139.

? Goniatites retrorsus var. typus – Sandberger & Sandberger 1851: pl. 10a figs 3–6, 10–11.

? Tornoceras simplex View in CoL – Foord & Crick 1897: 69, 107, text-figs 25d–f, 48.

? Tornoceras simplex mut. View in CoL ovata – Frech 1902b: 47, pl. 3 fig. 21.

non Tornoceras typum View in CoL – Becker 1993: 182, pl. 3 figs 3–4, text-fig. 68a. — Becker et al. 2000: pl. 2 figs 7–8. — Korn & Klug 2002: 156, text-fig. 143a–c.

non Tornoceras simplex View in CoL – Frech 1902: 47, pl. 5 fig. 8. — Wedekind 1918: 135, pl. 16 fig. 12, textfig. 40a.

Diagnosis

Tornoceras reaching about 90 mm conch diameter. Thickly pachyconic, subevolute early juvenile stage (ww/dm ~ 0.80; uw/dm ~ 0.35 at 2 mm dm), thickly discoidal and involute subadult stage (ww/ dm ~ 0.58; uw/dm ~ 0.08 at 10 mm dm), thinly discoidal and involute adult stage (ww/dm ~ 0.42; umbilicus closed at 30 mm dm). Whorl profile as wide as high in the subadult stage (ww/wh ~ 1.00 at 10 mm dm) and strongly compressed in the adult stage (ww/wh ~ 0.75 at 30 mm dm); whorl expansion rate very high in the subadult and adult stage (WER = 2.30-2.45). Flanks convex, convergent, umbilical margin continuously rounded. Without any ventrolateral grooves. Suture line with broadly rounded, asymmetric adventive lobe and high ventrolateral saddle.

Type material

Lectotype GERMANY • Rhenish Mountains, Oberscheld ; probably middle Frasnian (Adorf Limestone); designated by Becker (1993); figured by Sandberger & Sandberger (1850 –1856: pl. 10 fig. 14), Becker (1993: pl. 3 figs 1–3) and Korn (2021b: text-fig. 2), re-illustrated here in Fig. 4 View Fig ; specimen 53a; Wiesbaden Museum .

Additional material examined

GERMANY • 1 spec.; Rhenish Mountains , Oberscheld; middle Frasnian (Adorf Limestone); Erbreich Coll.; MB.C.4466 1 spec.; Rhenish Mountains , Oberscheld; middle Frasnian (Adorf Limestone); Koch Coll.; MB.C.30409 1 spec.; Rhenish Mountains , Dillenburg , Eiserne Hand (Grube Friedrich); middle Frasnian (Adorf Limestone); MB.C.30410 .

Description

Lectotype 53a (Wiesbaden Museum)

Fairly well-preserved specimen with 46 mm conch diameter in red limestone; it is largely chambered and the last half volution belongs to the body chamber ( Fig. 4 View Fig ). It is a thinly discoidal conch (ww/ dm = 0.40) with a closed umbilicus. The body chamber is obviously slightly distorted, resulting in a stronger convergence of the flanks (as shown in the original illustration by Sandberger & Sandberger 1850 –1856). Parts of the specimen are covered by shell material, which, however, is not well preserved and does not allow a detailed examination of the ornamentation. The suture line has a small, V-shaped outer lobe and a broadly rounded ventrolateral saddle. The adventitious lobe is twice as deep as the outer lobe and as deep as it is wide; it is broadly rounded and slightly asymmetric.

Remarks

The species has been discussed several times in the literature. A detailed revision and discussion was carried out by Korn (2021b); in this paper both the taxonomic problems and the conch morphology as well as the ontogenetic development are presented on the basis of further material from the Rhenish Mountains.

Table 1. Conch dimensions and ratios of Tornoceras typus (Sandberger & Sandberger, 1851), lectotype (Wiesbaden 53a).

Specimen dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR
Wiesbaden 53a 46.0 18.3 29.7 0.0 15.2 0.40 0.62 0.00 2.23 0.49

Kingdom

Animalia

Phylum

Mollusca

Class

Cephalopoda

SubClass

Ammonoidea

Order

Ammonoidea

SubOrder

Tornoceratina

SuperFamily

Tornoceratoidea

Family

Tornoceratidae

SubFamily

Tornoceratinae

Genus

Tornoceras

Loc

Tornoceras typus (Sandberger & Sandberger, 1851)

Korn, Dieter & Bockwinkel, Jürgen 2022
2022
Loc

Tornoceras typum

Korn D. & Klug C. 2002: 156
Becker R. T. 1993: 182
1993
Loc

Tornoceras typum

Korn D. & Klug C. 2002: 156
Becker R. T. 1993: 182
1993
Loc

Tornoceras simplex

Wedekind R. 1918: 135
1918
Loc

Tornoceras simplex mut.

Frech F. 1902: 47
1902
Loc

Tornoceras simplex

Foord A. H. & Crick G. C. 1897: 69
1897
Loc

Tornoceras simplex

Korn D. 2021: 149
Holzapfel E. 1895: 98
1895
Loc

Goniatites retrorsus var. typus

Sandberger & Sandberger 1851: 109
1851
Loc

Goniatites retrorsus var. typus

Sandberger & Sandberger 1851: 37
1851
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