Fig. 84. Stenopterygius hauffianus (SMNS 10460), skull. Scale equals 100 mm.
used in the literature for so long, H ungerbühler concluded
it would be in the best interest of nomenclatural stability
to suppress the name. CM concurs with his proposal.
W agner (1852A) used the term “variety” and Huene
(1931A) the term “mutation” for variants of the species,
both of which are treated here as being of subspecific rank.
The most striking feature of Stenopterygius quadriscissus
is the complete loss or extreme reduction of teeth in mature
individuals, maturity appearing to correspond to a mandibular
length of 400 mm (see McGowan [1979B: 96-97] for
discussion). Aside from this feature, S. quadriscissus lacks
any striking distinguishing features, being a very “ordinary
looking” ichthyosaur. The dolphin-sized S. quadriscissus
is the most common species in Holzmaden, and is the
faunal equivalent in the Upper Lias of Ichthyosaurus communis
in the Lower Lias.
Godefroit (1994) synonymized Stenopterygius mega-
cephalus, S. megalorhinus, S. macrophasma and S. cuneiceps
with S. quadriscissus. However, each of these species has
well developed teeth, with no tendency towards reduction
in size or number, so they cannot be referred to S. quadriscissus.
Maisch (1998B) was aware that mature individuals of
S. quadriscissus have extremely reduced teeth or lost them
altogether. Nonetheless, he still synonymized S. megace-
phalus with S. quadriscissus without giving reasons.
Stenopterygius hauffianus H uene, 1922
Fig. 84; PI. 12
Stenopterygius hauffianus H uene, 1922: 54 [partim]
Stenopterygius hauffianus; Huene, 1926: 76
Stenopterygius hauffianus typica H uene, 1931A: pi. 2, fig. 1
Stenopterygius crassicostatus antecedens H uene, 1931A: 364
Stenopterygius hauffianus; H uene, 1949: 81
Stenopterygius hauffianus; H uene, 1952: 5 7
Stenopterygius hauffianus; H auff, 1953: pi. 7b
Stenopterygius hauffianus; McGowan, 1979B: 104
Stenopterygius hauffianus; Godefroit, 1994: 35
[non]Stenopterygius hauffianus Huene, 1922: pi. 19, fig. 2
Type material: One of H uene’S (1 9 2 2 ) three syntypes,
GPIT 18387, was designated as the lectotype (McGowan,
1979B: 105).
Diagnosis: Snout short, snout ratio usually < 0 .6 6 ; orbit
large, orbital ratio > 0 .2 2 . Teeth usually small, often sparse,
but never absent. Skull appears small for size of body.
Presacral vertebrae > 4 5 ; preflexural vertebrae probably
> 8 2 . Forefins short and wide, aspect ratio < 2 .7 . Moderate
sized, total length < 3 .5 m; skull length < 6 0 0 mm
Occurrence: Primarily from the vicinity of Holzmaden,
southern Germany. The specimen reported to be from the
Upper Lias of Yorkshire, England (Huene, 1922: pi. 19,
fig. 2 ) does not appear to belong to this species. However,
S. hauffianus has been reported from the Toarcian of Ilmin-
ster, Somerset (McGowan, 1978) and from Luxembourg
(Godefroit, 1994: 35).
Stratigraphic range: Upper Lias; Lower Jurassic (Toarcian).
Remarks: S. hauffianus is most likely to be confused with
S. quadriscissus because of its tooth reduction. However, it
always has teeth. S. hauffianus also has a shorter snout and
larger orbit, reminiscent of the Lower Liassic species Ichthyosaurus
breviceps. The body is also longer relative to its
skull, with higher vertebral counts.
Huene (1931A) used the names Stenopterygius hauffianus
forma typica, and Stenopterygius crassicostatus mut
antecedens as varieties, which are treated here as subspecies.
Plate 12
Stenopterygius hauffianus, skull of SMNS 10460. Scale measures 100 mm.
Stenopterygius megacephalus H uene, 1922
Fig. 85; PI. 13
Ichthyosaurus quadriscissus (Quenstedt, 1856); Drevermann,
1914: fig. 2
Stenopterygius megacephalus Huene, 1922: 44
Stenopterygius megacephalus; H auff, 1925: pi. 6a
Stenopterygius quadriscissus; H auff, 1925: pi. 7
Stenopterygius megacephalus; Huene, 1931A: 358
Stenopterygius quadriscissus incessa Huene, 1931A: 355 [partim]
Stenopterygius megacephalus; H uene, 1949: 82
Stenopterygius promegacephalus H uene, 1949: 84
Stenopterygius megacephalus; H uene, 1952: 56
Stenopterygius megacephalus; H auff, 1953: pis. 4-5, 7a
Stenopterygius megacephalus; McGowan, 1979B: 106
Stenopterygius quadriscissus; Godefroit, 1994: 41-43
Type material: Only one of Huene’S (1922: 4 4 ) three syntypes
was located by McGowan (1979B: 107): an unnumbered
skeleton housed in the Amsterdam Lyceum, Vale-
riusplein 15, Amsterdam, The Netherlands. This complete
and well preserved skeleton w a s designated as the lectotype
(McGowan, 1979B: pi. 2 , fig. 3).
Diagnosis: Teeth numerous with no tendency toward reduction
in size or number. Presacral vertebrae >45; preflexural
vertebrae >80. Skull long and slender with long snout,
but snout ratio probably <0.70. Orbit not especially large,
orbital ratio <0.22; snout ratio >0.64; premaxillary ratio
>0.42. Head relatively large compared with body. Forefin
not markedly elongate, aspect ratio <2.7. Modest sized,
total length <3 m; skull length <500 mm.
Occurrence: Holzmaden, southern Germany.
Stratigraphic range: Upper Lias; Lower Jurassic (Toarcian).