opinion that nomenclatural stability would be best served
by the erection of a new species for the Australian material.
This is inappropriate because M’Coy’S original description
(1867) satisfies the requirements of Articles 11 and 12 of the
ICZN. P. longmani thus becomes a subjective junior synonym
for P. australis (M ’Coy).
Etheridge (1888) named Ichthyosaurus marathonensis
based on an isolated rostral segment. He did not give any
distinguishing features to differentiate it from Ichthyosaurus
australis M’Coy, 1867 and admitted that “it is possible
they may be identical.”
Platypterygius hauthali (Huene, 1927)
Myobradypterygius hauthali Huene, 1927: 29
Platypterygius hauthali; McGowan, 1972C: 17
Holotype: MLP 79-1-30-1, a partial forefin, figured by
Huene (1927: fig. 3), in the La Plata Museum.
Diagnosis: No apparent distinguishing features.
Occurrence: Cerro Belgrano, Santa Cruz Province, Argentina.
Stratigraphic range: Lower Cretaceous (Neocomian).
Remarks: For the present, this species serves for the reception
of New World material from the earliest Cretaceous. It
may well prove to be synonymous with the contemporaneous
European species, Platypterygius platydactylus.
Genus C a y p u llisa u ru s Fernandez, 1997A
Caypullisaurus FernAndez, 1997A: 480
Type species: Caypullisaurus bonapartei FernAndez, 1997A.
Diagnosis: Humerus with three distal facets, the anterior
one, the smallest, articulating with a preaxial accessory
element; facet for ulna smaller than radial facet and set off
obliquely such that its posterior margin is well proximal of
its anterior margin; phalanges polygonal, tightly packed;
elements in longest digit probably >20. Teeth reduced and
probably absent. Orbit not especially large, orbital ratio
probably <0.20; postorbital region broad.
Remarks: FernAndez (1997A) discussed the similarity of
Caypullisaurus with Ophthalmosaurus, which likewise has
reduced teeth and comparable cranial proportions. However,
she concluded that the forefin was “clearly different
from other Jurassic ichthyosaurs” (FernAndez, 1997A:
481). The most readily apparent difference is the polygonal
shape and close packing of the phalanges in Caypullisaurus,
in which regard it is more like that of Platypterygius or
Ichthyosaurus. The digits are also significantly longer, with
as many as 24 elements in the longest one. Their humeri,
however, are very similar, each having three distal facets,
the middle one, for articulation with the radius, being the
largest.
As there are so few articulated forefins of Ophthalmosaurus,
the comparisons possible between the two genera
are rather limited. If more material were available it is
possible that the differences might appear less significant,
perhaps warranting referral to Ophthalmosaurus.
Caypullisaurus bonapartei FernAndez, 1997A
Fig. 99
Ophthalmosaurus sp. indet. Gasparini & Goni, 1990
Caypullisaurus bonapartei FernAndez, 1997A: 480
Holotype: MACN-N-32, a partial skeleton, incomplete
beyond vertebra 53.
Diagnosis: As for genus.
Occurrence: Cerro Lotena, Neuquen Province, Argentina.
Stratigraphic range: Vaca Muerta Formation; Upper Jurassic
(lower Tithonian).
2. Species inquirendae
(listed alphabetically)
Cymbospondylus nevadanus Merriam, 1908
Merriam (1908: 124) described this species based on the
anterior caudal region of an ichthyosaur, including hind-
limb elements (UCMP10620), collected from the New Pass
Range, Nevada (Prida Formation; Middle Triassic: Ani-
sian). Merriam (1908) distinguished Cymbospondylus nevadanus
from C. piscosus based on several minor differences
in vertebrae and hindfin. The most remarkable is the robustness
of the tibia and fibula in the former (compare
Merriam, 1908: pis. 12-13). However, as stated earlier in the
entry for C. buchseri, long bones in basal ichthyopterygians
increased their L/W ratio with growth, so it is possible that
UCMP 10620 (C. nevadanus) was skeletally less mature
than UCMP 9947 (the only hindfin of C. piscosus). If this is
the case, the tibia and fibula of C. nevadanus would have
reached a similar L/W ratio as in UCMP 9947. Even in this
scenario, a mature individual of C. nevadanus would have
been larger than a mature C. piscosus, considering that
UCMP 10620 and 9947 are similar in size. Too little is
known about C. nevadanus at this point to discuss whether
it is a different variant of C. piscosus than is known. Therefore,
C. nevadanus is provisionally retained as a separate
species under Species inquirendae.
Guizhouichthyosaurus tangae Cao et Luo in Yin et al., 2000
Guizhouichthyosaurus tangae Cao et Luo in Yin et al., 2000:
16
Holotype: GMR 009, presacral portion of a skeleton with
well-preserved forefins.
Diagnosis: To be clarified.
Occurrence: Guarding, Guizhou, China.
Stratigraphic range: Wayao Formation; Upper Triassic
(lower Carnian).
Remarks: Three monotypic genera of medium-sized ichthyosaurs
were erected in Yin et al. (2000) — Guizhouichthyosaurus,
Typicusichthyosaurus, and Guanlingsaurus. They are
all based on specimens from the lower Carnian of the
Guarding area of Guizhou Province, China. Published
photographs suggest that these ichthyosaurs are indeed
different from each other, as Yin et al. (2000) claimed, at
least at the species level. However, the descriptions are
brief, and it is difficult to confirm whether the reported
differences among the taxa are sufficient to guarantee the
coexistence of three monotypic genera of similar-sized ichthyosaurs.
These three genera show shastasaurian features
in their fins and vertebral counts, and are probably closely
related to Besanosaurus, Shonisaurus, and Shastasaurus.
Guanlingsaurus is unique among the three for having a
very high presacral count of about 80, very short snout,
and poorly ossified forefins. No such ichthyosaur is known
elsewhere, and its generic status is probably warranted.
The other two are possibly congeneric, but a redescription-
al study is necessary before anything further can be established.
Ichthyosaurus ascissus Wurstemberger, 1876
Wurstemberger (1876: 224) described a three-meter long
skeleton, preserved from the ventral aspect, which was
housed in the Stuttgart museum. It was recovered from the
Upper Lias of Ohmden, Württemberg, Germany in 1860.
He said the skull was remarkably wide in the orbital region,
and that the snout became very narrow and pointed
anteriorly. The holotype was probably lost during World
War II.
Ichthyosaurus grandipes Sharpe, 1834
Sharpe (1834: 222) gave a brief description of a partial
skeleton, collected from the Lias (Lower Jurassic) four
miles from Stratford-upon-Avon, Warwickshire, England.
He estimated that the entire skeleton would have been
“about seven feet” long [2.1 m]. It comprised a crushed
skull, incomplete anterior to the external nares, a continuous
series of 52 vertebrae, one scapula, and an almost
entire pectoral fin. The teeth were “entirely wanting in this
individual” but Sharpe considered it a new species on the
grounds of two other features. First, the “length of each
vertebra is uniformly three fifths of its breadth . . . ”, a
proportion said to be unknown elsewhere. Second, the
forefin was “of great size” estimated at one-fifth of the
body length, with rounded rather than angular elements,
and with an emarginated radius. Lydekker (1889A: 83)
synonymized I. grandipes with I tenuirostris, a course followed
by Kuhn (1934: 54). Sharpe’s original material appears
to be lost so this synomymy cannot be verified.
However, his description of the forefin does appear consistent
with that of Leptonectes tenuirostris.
Ichthyosaurus ingens Theodori, 1854
This Early Jurassic species was erected upon an incomplete
humerus that had a distinctly constricted shaft, a partial
radius, and some other fin elements. A markedly constricted
humeral shaft is not unusual, and occurs in Leptonectes
and in Temnodontosaurus. However, the specimen was said
to be gigantic, with an estimated length of the radius of not
less than 0.22 m. This is twice as large as in the largest
specimens of Temnodontosaurus trigonodon. A similarly gi