polygonal when viewed from the front, but this shape
disappears in posterior view. He therefore conduded that
J. hexagonus was unfounded. Given the variability of centra
with their position in the vertebral column, and the infrequency
with which they are seen end-on, his objection is
valid.
Ichthyosaurus hüdesiensis Koken, 1883
This species was erected on some vertebrae, and a tooth,
from the Lower Cretaceous of northern Germany (Koken,
1883: 761, pi. 24, figs. 1-3). The material is indeterminate.
Ichthyosaurus indicus Lydekker, 1879
L ydekker described fifteen assodated vertebrae from a
Cretaceous horizon in India, which he considered equivalent
to the English Upper Greensand (Albian). By his own
admission he could not be “absolutely certain of the specific
distinctness of the Indian form.” However, he still
thought it worthwhile to erect the new species to show the
geographical range of the genus. The material is indeterminate.
Ichthyosaurus kokeni BrOili, 1908
This spedes was based by Broili (1908: 433,fig. 3, pi. 14,
figs. 1-10) on a complete humerus (fig. 3), a partial humerus,
intermedium, a basiocdpital, and several vertebrae.
The complete humerus is much expanded proximally,
probably due to a compression distortion. This indeterminate
material is from the Lower Cretaceous of Grodischt, in
the Carpathian Mountains of Romania.
Ichthyosaurus lacunosae Quenstedt, 1885(? )
Kuhn (1934:43) dted Quenstedt (1867) as the authority for
this Early Jurassic spedes, but this reference was not in-
duded in the literature dted, nor is there an entry for 1867
in the Bibliography o f Fossil Vertebrates. The spedes I. lacunosae
is briefly treated in Quenstedt (1885: 207), where
reference is made to some caudal vertebrae. It is not clear
whether this is the first dtation of the species, but the
material is indeterminate.
Ichthyosaurus latifrons Owen, 1840
König used this name for a poorly preserved partial skull
- presumably from the Lower Lias - without any description,
making I. latifrons K önig, 1825 a nomen nudum.
Owen (1840: 122-123) gave a very brief description in
which he referred to its unusually large parietal foramen,
and noted that, “the articular surfaces of the bodies of the
vertebrae present a flattened circumference.” The name
accordingly first became available in 1840. Owen subsequently
gave an extended description, figuring König’s
partial skull (Owen, 1881:119, pi. 27, fig. 1). This same skull
(BMNH R1122) was figured by L ydekker (1889A: fig. 33),
but he confused the issue by figuring a second skull
(1889A: fig. 31) that has subsequently been identified as
Leptonectes tenuirostris. L ydekker also included a specimen
which has now been identified as Eurhinosaurus longiros-
tris. Owen’s (1881) description referred to a second specimen,
an incomplete skeleton, “lacking both ends, but including
the trunk, with chief part of the skull .... ”. However,
much of his description was based upon the partial
skull, which he figured in dorsal view. The skull exhibits a
broad expanse of the frontals, but this is because the posterior
margins of the nasals, and medial margins of the
postfrontals, are incomplete. If these elements were not
damaged they would overlie more of the frontals, as in
Ichthyosaurus communis. The only unusual feature cited by
Owen in his description was the shortness of the angular,
which, “disappears parallel with the hind border of the
orbit.” The incomplete preservation of the skull makes
adequate comparisons with other taxa difficult.
Ichthyosaurus leucopetraeus Burmeister et Giebel, 1862
This species was erected upon a single vertebra and rib
fragment, from the Jurassic of Rio de Copiapo, Chile (Burmeister
& Giebel, 1862:123). The material is indeterminate.
Ichthyosaurus nasimowii Fahrenkohl, 1856
This Early Jurassic species was erected upon two vertebral
centra (Fahrenkohl, 1856: pi. 2). Both are unusual. The
first (Fahrenkohl, 1856: pi. 2, fig. 1) is remarkable for its
tapering shape, whereby one of its articular surfaces, probably
the posterior, has a smaller diameter than the other.
The other is unusual for the enormous depression on either
side, for articulation with the ribs. These paired rib facets
extend from the anterior to the posterior surfaces of the
centrum, and are reminiscent of those of plesiosaurs. However,
the neural arch is unfused (and lost), and there are no
ventral facets for the chevrons. The tapered first centrum
resembles the terminal caudals of a plesiosaur, but, again,
there are no chevron facets, and there are no lateral rib
facets. The centra are probably best regarded as pathological.
Ichthyosaurus normanniae Valenciennes, 1861B
This species was based on some cranial bones, including
the basisphenoid and basiocdpital, from the Kimmerid-
gian of Normandy, France (Valenciennes, 1861B: 1001).
The basiocdpital (Lennier, 1870: pi. 6, fig. 7) appears typical
of Ophthalmosaurus. Bardet et al. (1997) referred this
largely indeterminate material to Ophthalmosaurus sp.
Ichthyosaurus numismalis Fraas, 1892
Fraas (1892: 30, pi. 1) founded this species upon a rostral
segment, 0.25 m long, from the Lower Lias (Lower Jurassic:
lower Pliensbachian) of Kirchheim, Germany. The material
is inadequate for diagnostic purposes.
Ichthyosaurus ovalis Phillips, 1871
Erected for some “anterior dorsal, posterior dorsal, and
anterior caudal” vertebrae whose centra were said to have
“an oval outline of face” which was higher than broad
(PHILLIPS, 1871: 339). Such laterally compressed centra are
typical of apical and post-flexural vertebrae (see above in
descriptive section; Fig. 12). From the Kimmeridge Clay
(Upper Jurassic: Kimmeridgian) of Swindon (Wiltshire)
and Shotover (Oxfordshire), England.
Ichthyosaurus planartus Theodori, 1854
Named for the relative flatness of the dorsal articulations
of the vertebral centra, this species was erected upon a
rather fragmented and scattered partial skeleton. The skeleton,
from the Upper Lias (Toarcian) of Banz, Germany
was distributed over three separate slabs, believed to be
associated. The first slab contained many scattered vertebrae,
ribs, and a humerus; the second a vertebral series
with rib fragments; and the third a number of large mandibular
fragments, cranial elements, teeth, vertebrae, many
complete ribs, a scapula and coracoid. The teeth were
described as being indistinguishable from those of L. tenuirostris,
and the scapula and humerus resembled those of I.
trigonodon. However, the dorsal vertebrae were said to
differ from all other Banz species by the roundness of their
centra.
The incompleteness-of the holotype, and the minor
differences of the vertebral centra, undermine the validity
of the species.
Ichthyosaurus polyptychodon Koken, 1883
Koken (1883:737, pi. 23, fig. 1) based this species on a skull
fragment that extended from the anterior margin of the
orbit to the posterior boundary of the external naris. This
indeterminate material is from the Lower Cretaceous of
northern Germany.
Ichthyosaurus posthumus W agner, 1852B
Erected upon a single and quite unremarkable tooth from
the Upper Jurassic of southern Germany (Wagner, 1852B:
702, pi. 4, figs. 4-5).
Bauer (1898: pi. 2 7 ) figured the tail region of an ichthyosaur
which he referred to as Ichthyosaurus trigonus var.
posthumus (in modern taxonomic practice, this would be
considered as a subspecies). This material, like W agner’s,
is clearly indeterminate.
Ichthyosaurus psilonoti Fraas, 1891
Fraas (1891: 41) briefly described this Early Jurassic species,
based on some teeth, which he said were similar to
those of Ichthyosaurus communis. Such teeth are not diagnostic.
Ichthyosaurus quenstedti Zittel, 1890
Zittel (1890: 4 5 8 , fig. 4 2 7 ) erected this Early Jurassic species
upon a small segment of the rostrum. The material
lacks any particular distinguishing features.
Ichthyosaurus rheticus Sauvage, 1876
This was the second Rhaetian species that Sauvage (1876)
described on the basis of vertebral features, in his one-page
note on ichthyosaurs from Saone-et-Loire, France. As in
I. carinatus, the material is not determinate.
Ichthyosaurus saladensis Rusconi, 1949
Although most of the ichthyosaurs Rusconi (1949) treated
in this paper were from the Late Jurassic, he also described
some material from the Cretaceous. Ichthyosaurus saladensis
was erected upon some jumbled bones and teeth that Rusconi
(1 9 4 9 :7 0 -7 2 , fig. 11) interpreted as parts of the maxilla
and mandible. The material, which is indeterminate, is
Early Cretaceous (Berriasian) in age.
?Ichthyosaurus sanjuanensis Rusconi, 1949
This species was erected upon two vertebrae from the
Lower Jurassic of the Quebrada Honda, San Juan Province,
Argentina (Rusconi, 1949: 90, figs. 1-2). The generic designation
was in some doubt. In any event, the material is
indeterminate.
Ichthyosaurus sinuatus Theodori, 185 4
Kiprijanoff (1881: 8 7 , 8 9 ) cited Theodori (1 8 5 4 ) as the
authority of this species, from the Lias of Banz, Germany.
This is because Theodori (1854: 5 0 ) had used it as a variety
name for I. tenuirostris. Little information was given for the
species, but Kiprijanoff (1881: pi. 18) figured a tooth. This
material is indeterminate.
Ichthyosaurus steleodon Bogolubow, 1909
Bogolubow (1909: 5 0 , figs. 1-2; pi.' 2, figs. 6 -1 0 ) based this
species upon the anterior portion of a rostrum with a
fragmentary left mandibular ramus, a second mandibular
segment, and a vertebra. The teeth are fairly long and
robust, without any indication of reduction, which suggests
the material might be referable to Platypterygius. This
material, from the Lower Cretaceous (Hauterivian-Bar-
remian) of the Ul’yanovsk Region of Russia, is clearly too
incomplete for the erection of a new species.