Parvinatator wapitiensis Nicholls et Brinkman, 1995
Grippia cf. G. longirostris Brinkman, Z hao & Nicholls,
1992: 465
Parvinatator wapitiensis Nicholls & Brinkman, 1995: 5 22
Holotype: RTMP 89.127.8, a partial skull and associated
forefins.
Diagnosis: As for the genus.
Occurrence: Wapiti Lake area, British Columbia, Canada.
Stratigraphic range: Sulphur Mountain Formation; Lower
to possibly Middle Triassic (Olenekian to Ladinian).
Family Utatsusauridae nov.
Remarks: A family comprising a single genus named solely
for classificational convenience.
Genus Utatsusaurus Shkama,
Kamei et Murata, 1978
Utatsusaurus Shkama, Kamei & Murata, 1978: 83
Grippia Minoura, 1994: 64
Type species: Utatsusaurus hataii Shkama, Kamei & Murata,
1978.
Diagnosis: Medium-sized ichthyopterygian, approach-
ting 3 m in total length; tooth size small relative to skull
width (less than 0.05); squamosal not entirely eliminated
from supratemporal fenestra by supratemporal; interdav-
ide cruciform; prefrontal shelf prominent; transverse flange o f
pterygoid well-defined and anterolaterally projected; anterior
terrace o f supratemporal fenestra present; tooth implantation
subthecodont, with both dental groove and shallow socket; tooth
crowns mesiodistally compressed; humerus as wide proximally -
as distally; humerus longer than wide; ulnar facet o f humerus as
wide as radial facet; no more than five phalanges in any digit;
posterior dorsal vertebrae long.
Remarks: Some of the features in the diagnosis are based
on personal observations by RM of spedmens UHR 30691
and NSM-VP-20028.
Utatsusaurus hataii Shkama, Kamei e t Murata, 1978
Utatsusaurus hataii Shkama, Kamei, & Murata, 1978: 83
Grippia microdenta Minoura, 1994: 65
Holotype: IGPS 95941, anterior half of the skeleton of an
immature individual.
Diagnosis: As for the genus.
Occurrence: Utatsu Town (type locality: Tatezaki) and
Ogatsu Town, Miyagi, Japan.
Stratigraphic range: Osawa Formation; Lower Triassic
(Olenekian).
Remarks: A spedmen referred to Utatsusaurus by N icholls
& Brinkman (1993) from the Lower Triassic of British
Columbia shows features that are congruent with this taxonomic
identification. It probably belongs to the genus, or
to a very closely related form, but the material is unfortunately
too fragmentary for more detailed identification.
(Unranked) Eoichthyosauria
Motani, 1999B
Definition: The last common ancestor of Grippia longirostris
and Ichthyosaurus communis, and all its descendants.
Diagnosis: Metacarpal I without peripheral shaft; manus
longer than more proximal part of the forelimb; bidpital
rib facets present on at least several cervical vertebral centra.
Order Grippidia WiMAN, 1929
Definition: All .epichthybsaurS more closely related to
Grippia longirostris than to Ichthyosaurus communis.
Diagnosis: Eoichthyosaurs with posterior tooth crowns
rounded; multiple maxillary tooth rows; metacarpal I lunate.
Family Grippiidae Wiman,- 1933
Genus Grippia Wiman, 1929
Grippia W iman, 1929: 184
Type species: Grippia longirostris Wiman, 1929.
Diagnosis: Small to medium-sized grippidian; flange
posterior to the coronoid process of surangular; tooth
crowns small relative to skull width; first metacarpal lunate;
at least some phalanges with round proximal expansions;
humerus wider than long; humerus wider distally-than
proximally; prefrontal shelf prominent; transverse flange o f
pterygoid well-defined and anterolaterally projected; anterior
terrace o f supratemporal fenestra present; posterior dorsal vertebrae
long, with height/length ratio o f about 1.2; pronounced
deepening o f amphicoelous excavation o f vertebral centra near
center.
Grippia longirostris W iman, 1929
Grippia longirostris W iman, 1929: 184
Mixosaurus longirostris; McGowan, 1972B: 5.
Holotype: Destroyed during World War II; now only represented
by a cast (PMU R445). A partial skull associated
with some limb elements.
Diagnosis: As for the genus.
Occurrence: Agardh Range and Mt. Milne Edwards,
Spitsbergen, Svalbard.
Stratigraphic range: Upper Sticky Keep Formation; Lower
Triassic (Olenekian).
Remarks: Motani (2000A) was able to identify a group of
specimens that can be assigned to the species, so the loss of
the holotype does not pose a threat to nomenclatural stability.
Therefore, there is no need to designate a neotype
(ICZN Article 75).
There exists some confusion regarding the publication
date of this species. W iman’s p aper h a s the imprint date of
1928, bu t Huene (1930) cited it as 1929. The Bibliography of
Fossil Vertebrates followed H uene’s (1930) citation, which is
retained here.
Genus Chaohusaurus Young et Dong, 1972
Chaohusaurus Y oung & Dong, 1972: 11
Anhuisaurus Chen, 1985: 140
Chensaurus Mazin et al., 1991: 1208
Type species: Chaohusaurus geishanensis Y oung e t DONG,
1972.
Diagnosis: Small grippidian, with total length of less than
1 m; short snouted; posterior teeth labiolingually wide,
and swollen in lateral view; three or possibly more maxillary
tooth rows; radius with a very well developed antero-
proximal prominence; anterior flange of humerus notched,
at least in young individuals; strong positive allometry of
the forefin, resulting in unusually large forefin in adults;
prefrontal shelf not remarkable but present; humerus wider than
long; humerus distally wider than proximally; first distal carpal
possibly absent; posterior dorsal vertebrae very long, with
height/length ratio o f about 0.9.
Remarks: Some of the features in the diagnosis are based
on the personal observation (RM) of IVPP V4001 in 1998.
Note that only a cast of IVPP V4001 is stored at IVPP, and
that was the material studied by Motani & You (1998A-B).
The original specimen is housed in the Anhui Provincial
Museum, where RM examined it after the publication of
the cited papers.
Chaohusaurus geishanensis Y oung e t Dong, 1972
Chaohusaurus geishanensis Young e t Dong, 1972: 11
Anhuisaurus chaoxianensis Chen, 1985: 140
Anhuisaurus faciles Chen, 1985: 142
Chensaurus chaoxianensis; Mazin et al., 1991: 1208
Chensaurus faciles; Mazin e t al., 1991: 1208
Chensaurus chaoxianensis; Motani e t al., 1996: 3 4 7
Holotype: IVPP V4001 (currently housed at Anhui Provincial
Museum), a skeleton lacking most of the snout and
tail.
Diagnosis: As for the genus.
Occurrence: Chao and Wuwei counties, Anhui, People’s
Republic of China.
Stratigraphic range: Qinglong Formation; Lower Triassic
(Olenekian).
Order Ichthyosauria Blainville, 1835
Definition: All eoichthyosaurs that are more closely related
to Ichthyosaurus communis than to Grippia longirostris.
Diagnosis: External naris laterally oriented, with little exposure
in dorsal view; prefrontal-postfrontal bar forming
the dorsal orbital margin; postorbital eliminated from upper
temporal fenestra in lateral view; pineal foramen on
parietal-frontal border; transverse flange of pterygoid not
well defined; ulna without post-axial shaft; posterior dorsal
centra discoidal.
Family Cymbospondylidae Huene, 1948
Genus Cymbospondylus Leidy, 1868
Cymbospondylus L eidy, 1868:178
Type species: Cymbospondylus piscasus L eidy, 1868.
Diagnosis: Anterodorsal margin of scapula emarginated;
anterior flange of humerus slightly concave; 55 or more
presacral vertebrae; carpals round; metacarpals retaining
shaft, at least partially; probably pentadactyl; diapophyses reaching
anterior margin o f vertebral centra; pronounced deepening o f
amphicoelous excavation o f vertebral centra near center.
Remarks: Apart from the specimens belonging to the
three species described below, several fragmentary specimens
have been referred to Cymbospondylus. Excellent reviews
are found in Callaway & Massare (1989B) and
Sander (1989). The diapophysial facet on the vertebral
centra merges into the anterior margin of the bone in
Cymbospondylus, and this character has been used to refer
some spedmens to the genus (Sander, 1992; Massare &