Pseudokossmaticeras tercense Seunes 1891 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 tercense Seunes 1891 |
|
|
Diagnosis / Definition: |
Ward & Kennedy (1993):
Description.-
Best preserved Biscay specimen is wholly
crushed juvenile 37 mm in diameter. Coiling moderately involute,
with just under half previous whorl concealed. Ornament
of numerous narrow, crowded prorsiradiate ribs of variable
length. Primary ribs arise, either singly or in pairs from small
sharp umbilical bullae, strong, straight, and prorsiradiate on
inner flank, flexing forwards and weakening on outer flank. Up
to four shorter ribs between primaries, arising both high and
low on flank, to give total of 30-33 ribs per whorl. All ribs sweep
forwards and strengthen on ventrolateral shoulder, and cross
venter in convex course. Traces of ill-defined, distant constrictions
on both inner and outer whorls. |
Discussion / Comments: |
Ward & Kennedy (1993):
Type. -
Designated by Kennedy, 1986b, p. 1,008 the original
of Seunes, 189 1, p. 16, Pl. 15(6), fig. 4, an unregistered specimen
in the Sorbonne Collections (now in the Université de Paris VI),
from Tercis, Landes, France.
Discussion. -
The high whorls and dense crowded ribbing distinguish
Pseudokossmaticeras tercense from all other species
referred to the genus; see discussion in Thiedig and Wiedmann
(1 976) and Kennedy and Summesberger (1 987) for details. The
Biscay specimens differ in no significant respects from the lectotype
and topotypes we have seen, while large specimens from
Carinthia, Austria (Thiedig and Wiedmann, 1976, P1. 1, fig. 2,
Pl. 2, fig. 2), show the dense crowded ribbing to extend to maturity.
Occurrence. -
The Biscay specimens come from the Campanian-
Maastrichtian boundary (see Herm, 1965) and the base of
Member I, all at Zumaya. The species also occurs at Tercis,
Landes, France, but is imprecisely dated; in the niveau de transition between the Marnes de Plagne and Calcaire nankin at the
Picon de Roquefort, Haute-Garonne, France, the lower Maastrichtian
of Krappfeld, Carinthia, Austria, Bulgaria and the former
USSR. |
Systematics: |
38 Ordo Ammonoidea
Subordo Ammonitina
Superfamilia Desmocerataceae
Familia Kossmaticeratidae
Subfamilia Kossmaticeratinae
Genus Pseudokossmaticeras
Species Pseudokossmaticeras tercense
|
Synonym list: |
Ward & Kennedy (1993):
|
Stratigraphy - relative ages: |
lower Maastrichtian - lower Maastrichtian: Ward & Kennedy (1993)
|
References: |
Seunes,J.. (1891): Contributions à l’étude des Céphalopodes du Crétacé Supérieur de France. Ammonites du Calcaire à Baculites du Cotenin (Suite); II. Ammonites du Campanien de la région sous-Pyrénéenne, Département de Landes . Mémoirs de la Société Géologique de France, Paléontologie Vol. 2(2) p. 8-22
Kennedy,W.J.. (1986): Upper Campanian and Maastrichtian ammonites from the Petites-Pyrénées, southern France . Eclogae Geologicae Helvetiae Vol. 79 p. 1001-1037
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
|
This work is licensed under a Creative Commons Attribution 2.5 License.
|
|