Bactrites gracile Blumenbach, 1803

Kröger, Björn, Klug, Christian & Mapes, Royal, 2005, Soft-tissue attachments in orthocerid and bactritid cephalopods from the Early and Middle Devonian of Germany and Morocco, Acta Palaeontologica Polonica 50 (2), pp. 329-342 : 339

Bactrites gracile Blumenbach, 1803

Figs. 1A , 3C.

* Orthoceras gracile sp. nov.; Blumenbach 1803: pl. 2: 6. Orthoceratites gracilis Blumenbach ; d’Archiac and de Verneuil 1842:

344–345, pl. 27: 4. Bactrites gracilis sp. nov. [jun. homonym]; Sandberger 1843: pl. 8: 2. Orthoceratites crebriseptatus sp. nov. [nom. nud]; Roemer 1844: 81. Orthoceratites schlotheimii sp. nov. [nom. nud.]; Quenstedt 1845 –

1849: 44, pl. 1: 11. Bactrites gracilis Sandberger ; Sandberger and Sandberger 1850 –56:

130–131, pl. 11: 9, pl. 12: 2, pl. 17: 5. Orthoceratites schlotheimi Quenstedt ; Giebel 1852: 279. Orthoceratites schlotheimi Quenstedt ; Steininger 1853: 40, pl. 1: 12,

12a. Orthoceratites schlotheimii Steininger [lapsus calami] 1857; Eichwald:

201. Bactrites gracilis Sandberger ; Chénu 1859: 77, fig. 308. Bactrites gracilis Sandberger ; Eichwald 1860: 1261. Orthoceratites schlotheimii Quenstedt ; Quenstedt 1866: 407, pl. 34: 6. Bactrites schlotheimi (Quenstedt) ; Maurer 1876: 827. Bactrites Schlotheimi (Quenstedt) ; Koch 1881: 241 Bactrites gracilis Sandberger ; Chelius 1881: 12. Orthoceras schlotheimi, Steininger ; Foord 1888: 97–98. Bactrites gracilis Sandberger ; Clarke 1894: 40–43, figs. 2–5. Orthoceras schlotheimi Steininger ; Crick 1898: 87. Bactrites schlotheimi (Quenstedt) ; Maurer1896: 638. Bactrites schlotheimii (Quenstedt) ; Schindewolf 1933: 73, pl. 3: 2–6. Orthoceratites schlotheimii Steininger ; Teichert 1940: 590. Michelinoceras cf. schlotheimi (Steininger) ; Teichert and Glenister 1952: 737.

Bactrites schlotheimii (Quenstedt) ; Shimansky 1962: pl. 3: 6. Bactrites schlotheimi (Quenstedt) ; Gordon 1964: 101.

Bactrites gracilis Sandberger ; Gordon 1964: 102.

Bactrites schlotheimi (Quenstedt) ; Clausen 1968: 58–59, pl. 7. Bactrites schlotheimii (Quenstedt) ; Shimansky 1974: 811–812, pl. 3: 6. Bactrites schlotheimi Sandberger [sic]; Brinckmann 1977: 121, fig. 8. Syntypes: Sandberger and Sandberger (1850 –1856) in repository of NHW.

Type horizon and locality: Wissenbacher Schiefer , early Eifelian , Middle Devonian.Wissenbach near Dietz in the Rhenish Massif, Germany .

Material.—Specimen NHW 62.11/W−23/64, the original of Sandberger and Sandberger (1850 –1856: pl. 11: 9) from Wissenbach, syntype, preserves seven chambers of the phragmocone and body chamber, pyritised mould.

Diagnosis.—The shell is slightly compressed, with a very low apical angle, faint undulation of the shell with ventral sinus and dorsal lobe, and a faint lateral undulation that is oblique towards the growth axis. The chamber height is variable. The suture is slightly oblique towards the growth axis with a small ventral lobe and subspherical septa. Its initial chamber is ovate, smooth, with a circular cross section, ca. 0.9 mm wide and 1.2 mm long and highly variable in cross section from compressed to circular.

Description.—The mature characters were described in detail by Sandberger and Sandberger (1850 –1856) and numerous later authors (see above); the apex characteristics were described by Schindewolf (1933).

Remarks.—The extraordinarily long list of synonymy is given here in order to document a long established misinterpretation of putative “two” mid−Devonian bactritoid taxa. This misinterpretation resulted from the designation of the nomen nudum “ Orthoceratites schlotheimii ”, by Quenstedt (1845 –1849). Sandberger and Sandberger (1850 –1856) showed that it is a subjective junior synonym of B. gracile . Unfortunately, few copies of the latter were printed while Ouenstedt’s monograph had wider circulation. Because of the difference in publicity, the name “ O. schlotheimii ” became more popular for this typical “Wissenbach”−bactritoid, while the original was (and still is) not known to the great majority of palaeontologists. B. gracile and B. subconicus Sandberger, 1843 are the most common Bactritida in the Wissenbacher Schiefer.

Stratigraphic range and geographic occurrences.—Late Emsian–Givetian, Germany, England, USA.

Figures

Fig. 1. Soft−tissue attachment structures in cephalopods from the Wissenbach Schiefer (early Eifelian). A. Bactrites gracile (Blumenbach, 1803), NHW 62.11/W−23/64, dorsal view, note the two different grayish bands (arrows) forming a lobe. B. Bactrites sp. A, NHW 402, dorsal view (B1), note two successive, slightly undulated grooves. Same specimen, lateral view (B). Same specimen, ventral view (B), note the small lobe in suture line. Same specimen, +