Plate 9
Ichthyosaurus communis, forefin of neotype, BMNH R1162. Scale on photo measures 100 mm.
Fig. 81. Ichthyosaurus breviceps. A) skull (based upon BMNH 39263). B) forefin, depicted as left, dorsal view, holotype (BMNH
43006). Scales each equal 50 mm.
Ichthyosaurus breviceps Owen, 1881
Fig. 81; PI. 10
Ichthyosaurus breviceps Owen, 1881: 109
[non]Ichthyosaurus breviceps Owen, 1881: pi. 29, fig. 1
Ichthyosaurus breviceps; Lydekker, 1889A: 52
Eurypterygius breviceps; Huene, 1922: 8
[non]Eurypterygius breviceps; Huene, 1922: pi. 1, fig. 3
Holotype: BMNH 43006, a complete skeleton.
Diagnosis: Preflexural vertebrae < 74; presacral vertebrae
probably >41, and probably <44. Snout markedly short,
snout ratio <0.57; orbit large, orbital ratio >0.26. Forefin
probably with at least 7 digits; elements in longest digit
>20; no notching. Fairly small, total length probably <2m,
may not exceed 1.5 m.
Occurrence: Lyme Regis, Dorset, England.
Stratigraphic range: Lower Lias; Lower Jurassic (Hett-
angian-Sinemurian).
Remarks: Uncommon. The large, short-snouted skull
(BMNH R1157) that was referred to I. breviceps by Owen
(1881) and to E. breviceps by Huene (1922) is the holotype of
Temnodontosaurus eurycephalus McGowan, 1974A.
Ichthyosaurus conybeari Lydekker 1888
Fig. 82
Ichthyosaurus conybeari Lydekker, 1888: 312
Ichthyosaurus conybeari; Lydekker 1889A: 53
Eurypterygius conybeari; Huene, 1922: 8
Ichthyosaurus conybeari; McGowan, 1974B: 18
Holotype: BMNH 38523, an incomplete and poorly preserved
skeleton.
Diagnosis: Preflexural vertebrae >74; presacral vertebrae
<42. Snout long and slender; snout ratio >0.57; orbital ratio
<0.28. Notching occurs in some preaxial elements of fore-
fin; 6 digits, elements in longest digit <25. Small, probably
not exceeding total length of 1.5 m.
Occurrence: Lyme Regis, Dorset, England.
Stratigraphic range: Lower Lias; Lower Jurassic (Hett-
angian-Sinemurian).
Remarks: Rare. This species bears a superficial resemblance
to Leptonectes tenuirostris but is readily distinguished on
forefin features: phalanges numerous and close-packed;
humerus lacks prominent preaxial facet, shaft without
prominent constriction; radius lacks notch; no foramen
between radius and ulna (Fig. 82C). The single referred
specimen of I. conybeari, BGS 956, is a small (total length
870 mm), complete, and well-preserved skeleton from the
Lower Lias of Lyme Regis (Fig. 8 2; McGowan, 1974B: fig.
10).