Fig. 95. Platypterygius platydactylus, holotype, redrawn from Br o il i (1907). Scale equals 1 m.
Holotype: A partial skeleton, figured by Broili (1907: pi.
12), which was destroyed during WW II.
Diagnosis: No apparent distinguishing features.
Occurrence: Hannover and Salzgitter regions, Lower Saxony,
Germany.
Stratigraphic range: Lower Cretaceous (Aptian).
Remarks: The holotype humerus appears to have had a
rectangular rather than a ridge-shaped dorsal process
(Broili, 1907: pi. 13, fig. 16), and therefore appears unlike
that of other material referred to Platypterygius. However,
Broili (1907) noted that the specimen had undergone compression
during fossilization, and the atypical appearance
is therefore almost certainly a preservational artifact.
The forefin of Kuhn’s P. hercynicus (Kuhn, 1946: pi. 3,
fig. 6) h as seven rather than e ight d igits, w hich w as the sole
reason McGowan (1972C: 11) did not synonymize it with
P. platydactylus. Given the amount of variability found in
ichthyosaurian forefins, this difference is considered trivial
for taxonomic distinction.
Platypterygius campylodon (Carter, 1846A)
Fig. 96
Ichthyosaurus campylodon Carter, 1846A: 60
Ichthyosaurus campylodon; Carter, 1846B: 7-9
Ichthyosaurus campylodon; Owen, 1851: 69-80
Ichthyosaurus campylodon-, Lydekker, 1889A: 15-21
Myopterygius campylodon; Huene, 1922: 98 [partim]
Ichthyosaurus (Platypterygius) campylodon; Kuhn, 1946: 79
Platypterygius campylodon; McGowan, 1972C: 17
Holotype: Part of the rostrum, with numerous teeth, some
of which are in situ, the upper jaw extending “more than
two feet” (60 cm), from “the vicinity of Cambridge” (Carter,
1846B: 7). Several specimens in the Sedgewick Museum,
Cambridge, bear labels identifying them as type material.
Of these, SMC B20644, a 60-cm-long rostral segment, appears
to correspond to Carter’s (1846B: 7) description and
is considered the holotype.
Diagnosis: External longitudinal groove probably present
along length of rostrum and mandible.
Occurrence: England (primarily Kent and Cambridgeshire),
France and Russia.
Stratigraphic range: Lower Cretaceous-lower Upper Cretaceous
(Albian-Cenomanian).
Remarks: Kiprijanoff (1881) described some material, reportedly
from the Lower Cretaceous of the Kursk Region
of Russia, that he referred to I. campylodon Carter. Romer
(1968: 27), citing Nace (1941), considered Kiprijanoff’s
material sufficiently different to erect the new species,
Myopterygius kiprijanoffi, for its reception. N ace’s distinction
between the two species was based on differences in
proportions in the centra of the posterior dorsals. Given
the variability in centrum shape with position in the vertebral
column, these differences are considered trivial. However,
McGowan (1972C) pointed out another distinction
which seemed to warrant retaining a separate species, and
this had to do with the curvature of the teeth.
The specific name campylodon, meaning curved tooth,
was coined by Carter (1846A) in reference to the characteristic
curvature of the mandibular teeth, imposed by the
orientation of the dental groove, which is directed laterally
Fig. 96. Platypterygius campylodon, presumed holotype (SMC B20644). Scale equals 20 mm.
rather than dorsally. This is clearly shown in a transverse
section through the tip of the rostrum of one of Carter’s
specimens (Owen, 1851: pi. 26, fig. 2). Because Kiprijanoff’s
material did not show this feature, M cGowan
(1972C) concluded that the species P. kiprijanoffi should be
retained. However, tooth curvature is not a good diagnostic
character because it can be seen in other taxa. For
example, Sollas’s (1916: fig. 2 [11]) sections through the tip
of the mandible of Ichthyosaurus shows curved teeth like
those figured for P. campylodon. Given that Kiprijanoff’s
material lacks any distinctive features separating it from
other taxa, P. kiprijanoffi may be regarded as a nomen
dubium, and the material referred to P. campylodon. The
same can be said for the partial skull that A rkhangelsky
(1998B) referred to a new species, P. bannovkensis, from the
middle Cenomanian of the Saratov Region of Russia.
Most of the material from England is from the Lower
Chalk (Cenomanian), but there are also isolated elements
from the Upper Greensand (Albian) that are certainly referable
to Platypterygius and that can be referred to the
present species. As discussed by Bardet (1992), bones referable
to this species have also been found in the Petit
Blanc-Nez Formation (Albian) of France.
Platypterygius americanus (Nace, 1939)
Fig. 97
Myopterygius americanus Nace, 1939: 674
Myopterygius petersoni N ace, 1941: 908
Myopterygius americanus; Romer, 1968: 27
Platypterygius americanus; McGowan, 1972C: 17
Platypterygius americanus; M azin, 1982: 97
Fig. 98. Platypterygius australis. A) skull (QM F2453), modified from Wade (1990) to show only the left side. B) partial forefin (QM
F10686), depicted as a right one in dorsal view, redrawn from Wade, 1984. Scales equal 100 mm.