Pseudokossmaticeras duereri Redtenbacher 1873 from: Ward, P.D..Kennedy, W.J.. (1993): Maastrichtian Ammonites from the Biscay Region (France, Spain) . Memoir (The Paleontological Society), Journal of Paleontology34 (Supplement to Vol. 67)(5) p. 1-58
|Notice: This catalogue page may contain unedited data.
Species Pseudokossmaticeras duereri Redtenbacher 1873
|Diagnosis / Definition:
Ward & Kennedy (1993):
Holotype is crushed internal mold, distorted
into ellipse, with maximum diameter of 71 mm; all of inner
whorls missing. Coiling appears to have been serpenticone, with
wide umbilicus of moderate depth. Because of crushing, original
form of whorl section unclear, although umbilical wall rounded
and undercut, flanks broadly rounded and venter rounded. Estimated
five deep, strong, narrow, straight and prorsiradiate
constrictions per whorl. They are preceded by strong, parallel,
rounded rib with distinct, sharp umbilical bulla, and followed
by similar, but somewhat weaker rib. On first half of outer whorl,
which is rather badly deformed, there are an estimated 18 ribs
between two conspicuous constrictions. As preserved, these are
prorsiradiate, feebly flexed, and arise in groups of two or three
from small umbilical bullae. Occasional long, non-bullate ribs
extend to umbilical seam, and there are also shorter, intercalated
ribs. On last part of outer whorl, there are 12 ribs between last
two constrictions; all long, feebly prorsiradiate, and most bear
feeble umbilical bulla. Sutures undecipherable.
Small Biscay specimen is in form of silicone squeeze taken
from a natural mold, some 43 mm in diameter. Outer whorl
corresponds closely to that of holotype, final section showing
primary ribs arising singly from feeble umbilical bullae whereas
preceding part has ribs arising both singly and in pairs. Inner
whorls, not preserved in holotype, show that umbilical bullae,
9-10 per half whorl, were relatively prominent, and ribs weak.
Much larger is UWBM 76728, some 65 mm in diameter, with
crowded prorsiradiate ribs, great majority primaries, straight on
flank, but projected strongly forward on ventrolateral shoulder,
with maximum development across venter. Periodic constrictions
associated with strong collar-ribs.
|Discussion / Comments:
Ward & Kennedy (1993):
Holotype is the original of Redtenbacher, 1873, p.
106, Pl. 24, fig. l a d , No. 1873/01/22, in the collections of the
Austrian Geological Survey, from the Gosau Beds of Gosau,
Redtenbacher's figure is accurate, if reversed.
Pseudokossmaticeras duereri most closely resembles P. pacificum
(Stoliczka, 1865, p. 160, PI. 77, fig. 9), a species in which
all the ribs are long, with no branching or intercalation, save
near constriction, whilst they follow a somewhat concave course.
Madagascan examples illustrated by Collignon (1971, Pl. 64,
fig. 2398, Pl. 653, fig. 2418) show these features well, and are
somewhat sparser ribbed than is P. duereri.
Pseudokossmaticeras brandti (Redtenbacher, 1873) (p. 106,
Pl. 24, fig. 1; see Thiedig and Wiedmann, 1976) is coarsely and
sparsely ribbed at comparable diameters, as in P. aturicus (Seunes,
189 1, p. 17, Pl. 15(6), figs. 2,3), a synonym, which also possesses
more regularly bifurcating ribs. In P. galicianum (Favre, 1869)
(p. 16, Pl. 3, fig. 5a, b; see also Thiedig and Wiedmann, 1976,
p. 17, Pl. 2 figs. 1, 3), of which P. tchihatcheffi (Böhm, 1927)
(p. 2 17, Pl. 13, fig. 1) may be a synonym, constrictions are less
obvious, and there is a higher whorl section, smaller umbilicus,
and obvious alternation of long and short ribs at smaller sizes
(e.g., Naidin and Shimanskij, 1959, Pl. 13, fig. 1). Pseudokossmaticeras
tercense (Seunes, 189 1) (p. 16, Pl. 15(6), fig. 4; see above, and Thiedig and Wiedmann, 1976, p. 18, Pl. 1, fig. 2,
Pl. 2, fig. 2) may be similarly distinguished, and has many more
branching ribs. Pseudokossmaticeras muratovi Mikhailov, 195 1
(p. 77, Pl. 13, fig. 52) is also more coarsely ribbed, the ribs
branching high on the flank. Pseudokossmaticeras cerevicianum
(Petho, 1906) (p. 95, Pl. 6, figs. 2, 3) is much more coarsely
ribbed and bullate.
The Biscay specimens are from Member II (lower
Maastrichtian) and from just beneath the K-T boundary (Member
V, upper Maastrichtian) at Bidart, France. The age of the
holotype from Gosau, Austria, is not known.
|Ward & Kennedy (1993):
|Stratigraphy - relative ages:
|upper Maastrichtian - lower Maastrichtian: Ward & Kennedy (1993)
Die Cephalopodenfauna der Gosauschichten in den nordöstlichen Alpen: . Abhandlungen der königlich-kaiserlichen geologischen Reichsanstalt Vol. 5 p. 91-140
Über die Obersenone flyschfauna von Leszczyny . Beitr. Paläont. Geol. Öst.-Ung. Vol. 30 p. 191-205
Ammonoidea neocretacea . Fossilium Cat, (1: Animalia) Vol. 29 p. 244 pp.
Neubeschreibung der Redtenbacher'schen ammoniten- originale aus den Gosauschichten . Stockholm Contributions to Geology Vol. 2 p. 31-49
Ward,P.D.. and Kennedy,W.J.. (1993):
Maastrichtian Ammonites from the Biscay Region (France, Spain) . Memoir (The Paleontological Society), Journal of Paleontology34 (Supplement to Vol. 67)(5) p. 1-58
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