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Acanthoscaphites verneuilianus d'Orbigny 1841 from: Kennedy, W.J.. (1986): The ammonite fauna of the Calcaire à Baculites (Upper Maastrichtian) of the Cotentin Peninsula (Manche, France) . Palaeontology Vol. 29(1) p. 25-83
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Species Acanthoscaphites verneuilianus d'Orbigny 1841



Alternative name:
Diagnosis / Definition:
Kennedy (1986):
Description. Coiling very involute with tiny, deep umbilicus. Umbilical wall rounded and undercuton internal mould; umbilical shoulder narrowly rounded, fianks broadly rounded, converging to broadly rounded venter. Greatest breadth elose to umbilical shoulder, estimated whorl breadth to height ratio 0•78. Eleven narrow, distant primary ribs on outer whorl; these arise at umbilical seam, are feebly concave across umbilical shoulder, and straight and prorsiradiate across flanks. They may give rise to fine secondary ribs on outer flank, while up to six fine intercalated ribs, both single and branching, arise at various points on flank. They are set at an acute angle to succeeding primary rib, as though they were secondaries arising from adapical face ofthat primary. Secondary ribs pass across venter undiminished, but primary ribs decline markedly in strength across this region. At smallest diameter visible on holotype only primary ribs each bear feebleventrolateral bulla. These persist, and as size increases ventrolateral tubercles appear first on one, then on two secondary ribs. At same point in development a second tubercle appears on ventrolateral shoulder in inner ventrolateral position. At diameter of approximately 27 mm, rounded siphonal tubereles appear, corresponding in position to ventrol~teral tubercles,
Discussion / Comments:
Kennedy (1986):
Discussion. d'Orbigny's figure is reasonably accurate. Apart from the holotype, described above, there is a second, large specimen, MNHP R1271, from Fresville (ex de Vibraye Collection) that may belong here (PI. 16, figs. 20 and 21). It shows a rather similar ventrolateral ornament at a diameter comparable to that ofthe holotype, but beyond this the tubercles strengthen, while amid-lateral bulla appears on the primary ribs (PI. 16, fig. 21). Unfortunately poor preservation precludes fuller deseription, but it appears that the speeimen bears feeble umbilieal and lateral bullae, plus strong inner and outer ventrolateral tubereles from c. 50 mm onwards. A third speeimen, MNHP R12470, also from Fresville (ex Morgan Colleetion) is shown in Plate 16, figs. 7-10. The inner whorls to 27 mm elosely resemble those of the holotype, but beyond this the ribs eoarsen markedly (PI. 16, fig. 8) with primaries separated by a single seeondary; all ribs bear outer ventrolateral and siphonal tubercles with occasional interealated nontubereulate riblets (PI. 16, fig. 10). These differenees from the type suggest the presence of a second species, but with so few specimens, and knowing the range of variation shown by e.g. H. constrictus, deseribed above, it is reeorded as Acanthoscaphites sp. These small speeies with multiple tubereulation on the phragmoeone are very different from the giant type speeies, S. tridens Kner, 1848, as is revealed by study ofthe fine specimens (in NHMW and GBA Collections) from Nagorzany, Galieia, which include the originals of Favre (1869), where phragmocones lack tubercles. There are eloser similarities to S. trinodosus (Kner, 1848) (p. 11, pI. 2, fig. 2) in which there are feeble to obsolete umbilical bullae on nuclei, strengthening on the body¬chamber, and ventrolateral and siphonal tubercles on all but the early whorls; the absence ofinner ventrolaterals immediately distinguishes it from the present form, however. 'S.' pungens Binkhorst, 1861 (p. 32, pI. 5a3, fig. I; see also de Grossouvre 1908, p. 37, pI. 11, figs. 1 and 2) has re1ative1y coarse primary ribs on the flank, all of which bear ventrolateral elavi from an early stage, fine looped and intercalated ventral ribbing, and lacks a siphonal tubercle on the phragmocone. A. innodosus Naidin, 1974 (p. 178, pl, 62, fig. 1) lacks phragmocone tubercles and is a giant species. A. bispinosus Nowak, 1911 (p. 577, pI. 32, figs. 1-3) and A. quadrispinosus (Geinitz, 1850) (pI. 7, fig. 2; pI. 8, fig. 2) are both large species and lack multiple tuberc1es on the phragmocone.
Synonym list:
Kennedy (1986):
non 1842 Ammonites nodifer Hagenow. - Hagenow : p.565 pl. 9, fig. 19
1850 Ammonites verneuilianus d'Orbigny. - Orbigny : p.212
1894 Scaphites sp. verneuili d'Orbigny. - Grossouvre : p.253 pl. 36, fig. 2
1925 Scaphites verneuili d'Orbigny. - Diener : p.204
1986 Acanthoscaphites verneuilianus d'Orbigny. - Kennedy : p.74 pl. 16, figs. 15-17; text-fig. 10c
Was used in synonym list of:
Stratigraphy - relative ages:
upper Maastrichtian: Kennedy (1986)
References:

Hagenow,v.F.. (1842):
Monographie der Rugen'schen Kreideversteinerungen. 3. Abt. Mollusken. . Neues Jb. Miner. Geogn. Geol. Petrefakt. p. 528-579

Orbigny,A.D.. (1850):
Prodrome de Paleontologie stratigraphique universelle des animaux mollusques et rayonnes. Vol. 2 p. 428 pp.

Grossouvre,d.A.. (1894):
Recherches sur la Craie Supérieure, 2, Paléontologie. Les ammonites de la Craie Supérieure, Mémoirs pour Servir à l’Explication de la Carte géologique détaillée de la France (mis-dated 1893).. p. 264

Diener,C.. (1925):
Ammonoidea neocretacea . Fossilium Cat, (1: Animalia) Vol. 29 p. 244 pp.

Kennedy,W.J.. (1986):
The ammonite fauna of the Calcaire à Baculites (Upper Maastrichtian) of the Cotentin Peninsula (Manche, France) . Palaeontology Vol. 29(1) p. 25-83

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