The material is from the Cardita-Schichten (Upper Triassic:
Camian) of Austria. It is possibly referable to Shastasaurus,
but even the generic assignment requires better knowledge
of vertebral features of Middle Triassic ichthyosaurs.
Shastasaurus (?) merriami H uene, 1916
Huene (1916) erected Shastasaurus (?) merriami upon a vertebral
centrum from the Wellen-Dolomit (lower Muschelkalk;
Middle Triassic; Anisian) of the Black Forest, Württemberg,
which had previously been mentioned by Merri-
am (1908: 91). He also referred another centrum from the
same horizon to the same species (Huene, 1916: 3 0 ). Callaway
& Massare (1989B) found that these centra were
non-diagnostic, and this view is followed here.
Shastasaurus (?) nordensis Ochev in Polubotko et Ochev,
1972
The name Shastasaurus (?) nordensis appeared in Polubotko
& Ochev (1972) as a new species, with a specification that
Ochev was the sole author of the name. This authorship
designation is consistent with ICZN Article 50 and is valid.
The material is from the Middle Triassic (Ladinian) of the
Dyugadyak River basin in Russia (Callaway & Massare,
1989B). Mazin (1986: 118) considered it indeterminate,
which was followed by Callaway & M assare (1989B). This
view is supported here, and hence S(?) nordensis is a nomen
dubium.
Shonisaurus mulleri Camp, 1976
Camp (1976) based Shonisaurus mulleri upon a slab containing
the pelvic region of an ichthyosaur, and referred an
isolated humerus from a similar stratigraphic level to this
species. The specimens are from the Luning Formation
(Upper Triassic: Camian) of Nevada. McGowan & M otani
(1999) considered the specimens non-diagnostic. The species
is therefore a nomen dubium.
Shonisaurus silberlingi Camp, 1976
Shonisaurus silberlingi was based on an isolated humems
from the Luning Formation (Upper Triassic: Carnian) of
Nevada. McGowan & Motani (1999) found no diagnostic
feature on this specimen, and considered the species invalid.
The species should be treated as a nomen dubium.
Simbirskiasaurus birjukovi Ochev et Efimov, 1985
This species was erected upon a partial skull and associated
vertebrae, from the Lower Cretaceous (Hauterivian) of
the U lk’yanovsk Region of Russia (Ochev & Efimov, 1985:
88). The material, which is too incomplete to be diagnostic,
is not inconsistent with Platypterygius, and should accordingly
be referred to as Platypterygius sp.
Stenopterygius banzensis H uene, 1922
This species was founded upon a string of seven dorsal
vertebrae from the Lias of Banz, which, judging from
Huene’s (1922: 88, pi. 18, fig. 23) brief description and
illustration, are in no way unusual, and might be referable
to almost any species.
Stenopterygius grandis Cabrera, 1939
Cabrera (1939: 487, figs. 1-3) erected this species on a
fragment of rostrum from the Middle Jurassic (Bajocian) of
Curru-Charahuilla, Neuquen, Argentina. This material is
not diagnostic.
Spitsbergenosaurus crassidens M azin, 1981B
This genus and species was erected upon three partial
teeth (Mazin, 1981B). The teeth are much larger than those
of other ichthyosaurs occurring in the upper Sticky Keep
Formation (Grippia Level; Lower Triassic: Olenekian) of
Spitsbergen. Mazin (1981B) diagnosed the species based
on the large tooth size, open root with strong plications,
and conical crowns with fine striations. The latter two
features are plesiomorphic for ichthyopterygians, and size
alone cannot diagnose a valid species. The species is therefore
considered invalid, following Motani (1999B).
4. Nomina nuda
Ichthyosaurus advena P hillips, 1871
The only mention of this species made by Phillips (1871:
183) was that very few remains had been found at Stones-
field, Oxfordshire (Middle Jurassic: Bathonian), and that
“only vertebrae have been recorded.”
Ichthyosaurus angustidens Seeley, 1869
Seeley (1869: xv, 3 ) merely mentioned under this designation
a tooth from the chalk of Hunstanton, Norfolkshire.
Ichthyosaurus bonneyi SEELEY, 1869
This species was merely listed as occurring in the Upper
Greensand (Albian) of Cambridge (Seeley, 1869: xvii).
There was no mentioning of the material.
Ichthyosaurus chalarodeirus Seeley, 1869
Seeley (1869: 106) made reference to an unfused axis vertebra
from the Kimmeridge Clay (Upper Jurassic: Kim-
meridgian), near Ely, Cambridgeshire. No other information
about the specimen was provided. He must have been
mistaken about the taxonomic identity of the vertebra
because the atlas and axis are fused in post-Triassic taxa.
Ichthyosaurus doughtyi Seeley, 1869
Same comment as for I. bonneyi.
Ichthyosaurus giganteus Owen, 1840
Owen (1 8 4 0 :1 1 2 ) included this Early Jurassic species in his
synonymy of I. platyodon, citing L each as the authority.
Other sources, including L ydekker (1889A: 94) and Kuhn
(1934: 56), similarly refer to Owen (1840), citing L each as
authority, but no mention is made of the original citation.
Owen (1840: 112) stated that “Dr. Leach had previously
figured portions of the jaws and teeth under the name of
Ich. giganteus”, but gave no reference to the work. A publication
by L each cannot be located, and it is concluded
there may not have been one. The authority for this species
is thus taken as Owen, 1840. In any event the material upon
which the species was erected is indeterminate.
Ichthyosaurus hectori L ydekker, 1889A
L ydekker (1889A: 113) proposed the name Ichthyosaurus
hectori to replace Ichthyosaurus australis Hector, 1873, which
was preoccupied. He indicated a possible affinity of this
species with Mixosaurus, but it was not until Mazin (1986:
1118) that the specific name hectori appeared in combination
with the generic name Mixosaurus. The holotype, a
single vertebral centrum, is supposed to be from the Triassic
(Hector, 1873: 355). H ector (1873) gave no description
or figure of the type specimen, and neither did L ydekker
(1889A). This name is thus considered a nomen nudum.
Ichthyosaurus hygrodeirus Seeley, 1869
This species, like I. chalarodeirus, was erected upon a “free”
axis vertebra. Seeley (1869:106) said the species was “distinct”
from I. chalarodeirus, but did not elaborate.
Ichthyosaurus platymerus Seeley, 1869
Same comment as for I. bonneyi.
5. Non-ichthyosaurian
Genus Omphalosaurus M erriam, 1906
Omphalosaurus was first described as non-ichthyosaurian
by Merriam (1906), and after a debate with Wiman (Merriam,
1911; Wiman, 1916), a consensus was reached that it
was indeed not ichthyosaurian. However, a close relationship
between Omphalosaurus and ichthyosaurs was suspected
by Huene (1922), and this idea was later adopted
into formal classification by Kuhn (1934), who assigned
basal ichthyopterygians to the Omphalosauridae. Motani
(2000B), based on a redescription of the type material,
concluded that Omphalosaurus was not ichthyosaurian, but
he could not establish other affinities for the genus. This
view is followed here, but see Sander & Faber (1998) for an
opposing view. Four species have been referred to Omphalosaurus,
of which the second was regarded as a nomen
dubium by Sander & Faber (1998): O. nevadanus Merriam,
1906 (Prida Formation, Nevada); O. nisseri Wiman, 1916
(upper Sticky Keep Formation, Spitsbergen); O. nettarhyn-
chus Mazin et Bucher, 1987 (Prida Formation, Nevada);
and O. zoolfi Tichy, 1995 (Hallstätter Kalk, German-Austrian
border region).