Phyllopachyceras forbesianum d'Orbigny 1850 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.
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Species Phyllopachyceras forbesianum d'Orbigny 1850 |
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[1] Text-fig. 3b-c Ifrim et al. (2004) [2] pl. 1, figs. 1-4 Ifrim et al. (2004)
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Diagnosis / Definition: |
Ifrim et al. (2004):
Description: Involute and inflated with high expansion rate. The umbilicus is deep and too small to be accurately
measured. In juvenile specimens the steep umbilical wall bends widely into evenly convex flanks. The venter is
broadly rounded. In consequence, the whorl section is almost circular. In more adult specimens the umbilical wall
bends more narrowly into a slightly convex dorsolateral flank. The steep umbilical wall is almost absent and leads to a funnel-shaped umbilicus. Internal moulds are smooth. Where preserved the test is covered with dense lirae. Lirae are straight and slightly prorsiradiate on the middle flank and venter. The suture line displays tetraphylloid saddle
terminations on the first two saddles, E exceeds L in depth.
Ward & Kennedy (1993):
Description. -
Biscay specimens well preserved, and up to 85
mm in diameter. Coiling very involute, with tiny, near-occluded
umbilicus comprising less than 5 percent of diameter; whorls
expand rapidly. Inner flank flattened and defines broad circumbilical
pit; outer flanks and venter broadly rounded. Typical
ornament shown from whorl height of 18 mm onwards. Surfaces
of composite molds covered in delicate, dense lirae, straight and
prorsiradiate on flanks but flexed backwards on ventrolateral
shoulders to cross venter in broad convexity. Lirae accompanied
by low, broad distant ribs, most conspicuous on outer flanks
and venter, and covered in lirae, as are interspaces. Large specimens
show marked strengthening of lirae on venter so that
ventral ribs are combined with coarsely lirate ventral zone. Suture
complex, with phylloid folioles and straight suspensive lobe. |
Discussion / Comments: |
Ifrim et al. (2004):
Type: Ammonites forbesianus Forbes (1846, pl. 8, fig.6) was introduced as a new name for Ammonites Royanus
d'Orbigny without designation of aholotype. Lectotype BMNH C51081 was subsequently designated by Kennedy and
Henderson (1992b, p. 396, pl. 2, figs 1-3) from the original type series.
Remarks: Most specimens are immature with almost circu1ar whorl sections. Whorl section gradually
increases in height beginning with a whorl diameter of 10mm for some specimens, whi1e others remain
immature to a 1arger diameter.
Occurrence: The earliest reeords of this eosmopolitan speeies are from the Santonian of Madagasear (Collignon 1956, 1969) and the Lower Campanian of Spain (Wiedmann 1962). Later reeords ofCampanian-Maastriehtian ages include
southern India (Kennedy and Henderson 1992b), Japan (Matsumoto 1942), Alaska (Jones 1963), western Australia
(Henderson and MeNamara 1985), New Zealand (Marshall 1926; Henderson 1970), Austria (Kennedy and Summesberger 1986), the Biseay region of Franee and Spain (throughout the G. gansseri and A. mayaroensis zones; Ward and Kennedy 1993), Antarctica, South Africa, Gerrnany, and the former USSR (see Kennedy and Henderson 1992b). During the Late Campanian-Late Maastriehtian the speeies oeeurs world-wide through all latitudes (Alaska to the Antaretie Peninsula). Phyllopachyceras forbesianum is the most widespread among the speeies deseribed herein.
Ward & Kennedy (1993):
Types.-
Syntypes are BMNH C5 108 1-5 1086,24197, including
the original of Forbes, 1846, Pl. 8, fig. 6, all from the Valudavur
Formation of Pondicherry, south India.
Discussion.-
The largest paratype of this species, BMNH
C510824, is shown in Figure 18.5-18.7. It shows the same distinctive
flank and venter ornament as the Biscay specimens, the
identity of which cannot be in doubt. The stout whorl section
and ornament immediately distinguish Phyllopachyceras forbesianum
from all other phylloceratids in the present collections.
See Henderson (1970) for a full discussion of this species and
its synonyms.
Occurrence.-
In the Biscay sections this taxon ranges from
the middle of Member I (lower Maastrichtian) to the base of
Member V (upper Maastrichtian). Elsewhere, the species is recorded
from south India, Madagascar, Japan, British Columbia,
Alaska, California, New Zealand, western Australia, the Sub-
Antarctic islands, southern Argentina, Spain, north Germany,
Neuberg, Steiermark, Austria, and Galicia in the former USSR. |
Systematics: |
36 Ordo Ammonoidea
Subordo Phylloceratina
Superfamilia Phyllocerataceae
Familia Phylloceratidae
Subfamilia Phylloceratinae
Genus Phyllopachyceras
Species Phyllopachyceras forbesianum
38 Ordo Ammonoidea
Subordo Phylloceratina
Superfamilia Phyllocerataceae
Genus Phyllopachyceras
Species Phyllopachyceras forbesianum
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Synonym list: |
Ifrim et al. (2004):
Ward & Kennedy (1993):
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Was used in synonym list of: |
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Stratigraphy - relative ages: |
Maastrichtian - Santonian: Ifrim et al. (2004)
upper Maastrichtian - lower Maastrichtian: Ward & Kennedy (1993)
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References: |
Forbes,E.. (1846): Report on the Cretaceous fossil invertebrates from southern India, collected by Mr. Kaye and Mr. Cunliffe . Transactions of the Geological Society of London Vol. 2(7) p. 97–174
d'Orbigny,A. (1850): Prodrome de Paléontologie. Stratigraphique universelle des animaux mollusques & rayonnés faisant suitre au cours élémentaire de paléontologie et de géologie stratigraphique. , Cours Élémentaire de Paléontologie et de Géologie Stratigraphiques Vol. 2
Kossmat,F.. (1895): Untersuchungen über die Südindische Kreideformation. Erster Theil . Beiträge zur Paläontologie Österreich-Ungarns und des Orient Vol. 9 p. 97-203
SHIMIZU,S.. (1935): The Upper Cretaceous cephalopodes of Japan, part 1. . Journal of the Shanghai Science Institute Vol. 2(2) p. 159-226
JONES,D.L.. (1963): Upper Cretaceous (Campanian and Maastrichtian) ammonites from southern Alaska . United States Geological Survey Professional Paper Vol. 432 p. 1-53
Henderson,R.A.. (1970): Ammonoidea from the Mata Series (Santonian - Maastrichtian) of New Zealand . Special Papers in Palaeontology Vol. 6 p. 1-82
Dundo,O.P.. (1971): Maastrichtian fossils from the northern chalk. p. 84-92 [in Russi
Henderson,R.A.. and McNamara,K.J.. (1985): Maastrichtian non-heteromorph ammonites from the Miria Formation, Western Australia . Palaeontology Vol. 28 p. 35-88
Kennedy,W.J.. and Summesberger,H.. (1986): Lower Maastrichtian ammonites from Neuberg, Steirmark, Austria: . Beiträge zur Paläontologie von Österreich Vol. 12 p. 181–242
Kennedy,W.J.. and Henderson,R.A.. (1992): Non-heteromorph ammonites from the Upper Maastrichtian of Pondicherry, south India . Palaeontology Vol. 35 p. 381-442
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
Ward,P.D.. and Kennedy,W.J.. (1993): Maastrichtian ammonites from the Biscay Region . Journal of Paleontology Vol. 67(5 II) p. 1-58
Ifrim,C..; Stinnesbeck,W.. and López-Oliva,J.G.. (2004): Maastrichtian cephalopods from Cerralvo, north-eastern Mexico . Palaeontology Vol. 47(6) p. 1575–1627
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