radius
ulna
posterior accessory
element
intermedium
Fig. 94. Brachypterygius extremus. A) skull (SMC J68516). B-C) forefins (BMNH R3177, BRSMG Cc 16696), each depicted as a right one
in dorsal view. D-F) basiocdpital (SMC J68516), in posterior, left lateral, and anterior views. Scales equal 100 mm.
than condyle, from which it is not clearly set off.
Remarks: Huene (1922) erected the genus Brachypterygius
for reception of Ichthyosaurus extremus Boulenger, 1904
from the Upper Jurassic (Kimmeridgian) of England. Represented
only by an isolated forefin, I. extremus was unusual
for possessing a humerus with three distal facets, the
middle one of which articulated with the intermedium. No
other material was known at that time, except for a companion
forefin (see Remarks, below). Half a century later,
McGowan (1976) described an isolated skull from the
Plate 18
Brachypterygius extremus, SMC J68516. Scale measures 500 mm.
Kimmeridgian of England and referred it to a new genus,
Grendelius. A second specimen of Grendelius was subsequently
discovered - an almost complete skeleton, in
which initially only the skull had been prepared (SMC
J68516). Several years later, further preparation revealed a
forefin very similar in structure to that of I. extremus, establishing
the synonymy of Grendelius with Brachypterygius
(McGowan, 1997).
Efimov (1998) erected a new genus and species, Otsche-
uia pseudoscythica, upon a partial skeleton, comprising
skull fragments, pectoral girdle and limbs, and a series of
vertebrae, from the Upper Jurassic (lower Volgian, corresponding
to Tithonian) of the Ul’yanovsk Region of Russia.
The forefin (Efimov, 1998: fig. 4) clearly corresponds to
that of Brachypterygius, and E fimov (1998: 82) even commented
that the intermedium, which is wedged between
the radius and ulna, contacts the humerus, a condition
hitherto “noticed only in the genus Brachypterygius ... .”
Regardless, he still erected a new genus for its reception,
seemingly on the grounds that Brachypterygius “belongs to
the superfamily Brachypterygiidae.” Without referring to
Brachypterygius again, he made comparisons with Lepto-
nectes (then referred to as Leptopterygius), Stenopterygius,
Temnodontosaurus, Platypterygius, and Plutoniosaurus (here
synonymized with Platypterygius).
Brachypterygius extremus (Boulenger, 1904)
Fig. 94; PI. 18
Ichthyosaurus extremus Boulenger, 1904: 425
Brachypterygius extremus Huene, 1922: 97
Grendelius mordax McGowan, 1976: 671
Brachypterygius zhuravlevi A rkhangelsky, 1998A: 90
Otschevia pseudoscythica Efimov, 1998: 83
Holotype: BMNH R3177, an associated forefin (Fig. 94B).
Diagnosis: Of the three distal facets of the humerus, the
middle one is the smallest. Seemingly moderate-sized to
large ichthyosaur, humerus may be >80 mm long.
Occurrence: Smallmouth Sands, Weymouth, Dorset, and
Stowbridge, Norfolk, England. Also from the Ul’yanovsk
Region of Russia.
Stratigraphic range: Kimmeridge Clay; Upper Jurassic
(Kimmeridgian-Tithonian).
Remarks: The slight differences between the forefins of
BRSMG Cc 16696 and BMNH R3177, which includes having
five rather than six digits, do not warrant taxonomic
separation, so the former specimen should be referred to B.
extremus.
Delair (1986) reported that the companion forefin to
the holotype is in the collection of the Woodspring Museum,
Weston-super-Mare, Dorset (WESTM 78/219) and
gives a useful account of the early history of the material.
FernAndez (1997A: 483) argued that some material
from the Solnhofen Formation (Tithonian) of Bavaria,
housed in the Bayerische Staatssammlung fur Palaontolo