1 E o
Fig. 77. Selected species of Temnodontosaurus. A) Temnodontosaurus trigonodon, complete skeleton (SMNS15950/ only left side of skeleton
shown), scale measures one meter. B-C) Temnodontosaurus platyodon, skulls. Notice the straight profile of the snout in B) a mature
individual (BMNH R1158), and in C) the curving profile of the immature individual (privately owned specimen, presently housed at
BRSMG); scales equal 200 mm. D) Temnodontosaurus platyodon, forefin (largely based on-OUMNH J29170). E) Temnodontosa:urus
trigonodon, forefin (SMNS 50,000). Both fins depicted as left ones, in dorsal view; scales equal 200 mm. F) Temnodontosaurus eurycephalus
(BMNH R1157); Scale equals 200 mm.
Plate 5
Temnodontosaurus platyodon, skull of Mary Arming’s first ichthyosaur, BMNH R1158. Scale measures 500 mm.
peg, but this is considerably less well developed than the
prominent structure seen in Ichthyosaurus.
Temnodontosaurus platyodon (Conybeare, 1822)
Fig. 77B-D; PI. 5
Ichthyosaurus platyodon Conybeare, 1822: 108
Ichthyosaurus chiroligostinus H awkins, 1834: 14
Oligostinus H awkins, 1840: 10
Ichthyosaurus platyodon; Owen, 1840: 112
Ichthyosaurus lonchiodon Owen, 1840: 116
Ichthyosaurus platyodon; Owen, 1881: 115
Ichthyosaurus lonchiodon; Owen, 1881; 117
Ichthyosaurus lonchiodon; L ydekker, 1889A: 92
Ichthyosaurus platyodon; L ydekker, 1889A: 94
Temnodontosaurus platyodon; Lydekker, 1889B: XI
Leptopterygius lonchiodon; Huene, 1922: 16
Leptopterygius platyodon; Huene, 1922: 18
Proteosaurus platyodon; McGowan, 1972A: 5
Temnodontosaurus risor McGowan, 1974A: 17
Temnodontosaurus platyodon; McGowan 1996B: 1014
Holotype: A single tooth, formerly in the Geological Society
of London (Woodward and Sherborn, 1890: 240) and
now apparently lost (Delair, 1960: 71). McGowan (1974A:
12) designated BMNH 2003, a large and almost complete
skeleton, as the neotype.
Diagnosis: Forefin notching restricted to radius and next
one or two elements; forefin not exceptionally long, number
of elements in longest digit probably <17; presacral vertebrae
probably <48; rostrum not exceptionally long, snout
ratio usually <0.65, but >0.59.
Occurrence: Lyme Regis, Dorset, England; vicinity of Ar-
lon, southern Belgium (Godefroit, 1993A).
Stratigraphic range: Lower Lias; Lower Jurassic (Het-
tangian-Sinemurian).
Remarks: Hawkins (1840) modified his replacement name,
Ichthyosaurus chiroligostinus, and elevated it to generic status
as Oligostinus.
Most o f the referred specimens are incomplete so T. platyodon
is no t well known. This reduces confidence in the
diagnosis. The fairly wide rang e of variation among specimens
might be attributable to the inadvertent lumping of
large individuals of more than one taxon, rather th an to
individual variation within a single species (McGowan,
1996B). The skull is larger relative to the body than in the
closely similar Temnodontosaurus trigonodon.
Temnodontosaurus trigonodon (Theodori, 1843)
Fig. 77A ,E; PI. 6
Ichthyosaurus trigonodon Theodori, 1843: 912
Ichthyosaurus multiscissus Quenstedt, 1885: pi. 15, fig. 11
Ichthyosaurus burgundiae Gaudry, 1891: 171 [nomen nu dum]
Ichthyosaurus acutirostris (Owen); Fraas 1891: 66 [partim]
Ichthyosaurus burgundiae Gaudry, 1892: 367
Ichthyosaurus ingens Theodori, 1 854; Fraas 1891: 6 0 [partim]
Leptopterygius acutirostris (Owen); Huene, 1922: 25
Leptopterygius trigonodon; Huene, 1931 A: 371 [partim]
Leptopterygius acutirostris; H auff, 1953: 16
Leptopterygius burgundiae; McGowan, 1979B: 119