ilium
femur
fused pubis and ischium
radius
Fig. 83. Stenopterygius quadriscissus. A) complete skeleton. B) skull. C) forefin, depicted as right, in dorsal view. D) pelvic girdle, with
femur. Scales equal 100 mm, except in D (40 mm). All based upon ROM 3180, except B), which is based upon SMNS 6293.
an (1979B). This large skeleton (GPIT 43/0219-1), which
contains a large embryo, has a total length of approximately
3m and was designated the lectotype (McGowan,
1979B: 103). Hungerbuhler (1994: 249, figs. 3-6) located
and figured four more of Quenstedt’s original specimens:
GPIT 1491/9, GPIT 1491/6, GPIT 1491/8, and GPIT 43/
26/3, all of which are complete or nearly complete skeletons.
Diagnosis: Teeth extremely reduced in size and number
with maturity, leading to complete loss. Presacral vertebrae
<45; preflexural vertebrae <82. Forefin usually with 5
digits, rarely 4 or 6. Snout moderate to long, snout ratio
>0.60 but not often >0.66; orbit not especially large, orbital
ratio <0.24, and usually <0.22 or equal. Medium sized,
total length <3.5 m; skull length <650 mm.
Plate 11
Stenopterygius quadriscissus, skull of SMNS 6293. Scale of photo measures 50 mm.
Occurrence: Mainly from Holzmaden and vicinity, southern
Germany; probably also from Whitby, Yorkshire, England.
Stratigraphic range: Upper Lias; Lower Jurassic (Toar-
cian).
Remarks: The publication date for Quenstedt (1856) is
usually given as 1858 (Lydekker, 1889A: 114; Kuhn, 1934:
49; McGowan, 1979B: 102). However, Hungerbuhler (1994:
250) pointed out that this work was published in four parts
and the 1858 date on the title page date is misleading
because the relevant section on ichthyosaurs was actually
published in 1856. Quenstedt (1856) named two species,
Ichthyosaurus quadriscissus and Ichthyosaurus triscissus, based
on the number of notched elements on the leading edge of
the forefin (four and three, respectively). However, it has
been noted that this character is quite variable within
species (McGowan, 1979B), so it could be that Quenstedt’s
(1856) two species were one and the same. The holotype of
Ichthyosaurus triscissus Quenstedt, 1856, a 2-m-long skeleton,
was not figured, and the material was thought to be
lost (McGowan, 1979B: 132). However, Hungerbuhler
(1994: 250, fig. 1) has subsequently relocated this specimen
(GPIT 12/0224-2). The rather poorly preserved skeleton is
2.16 m long, and few measurements can be taken, making
comparisons with other specimens difficult. Hungerbuhler
(1994) noted that it had “strong, numerous teeth”.
Therefore, the specimen cannot be referred to Stenopterygius
quadriscissus, and Hungerbuhler (1994) was inclined
to refer it to Stenopterygius megacephalus. Given the uncertainties
of its features, and that I. triscissus has not been