In Case 3560, Galton applied for the designation of a neotype, the almost complete
skeleton SMNS 13200, for the basal sauropodomorph taxon Plateosaurus engelhardti
Meyer, 1837 (Upper Triassic, Germany).
Sues (BZN 70: 120–121) noted that the lectotype sacrum (UEN 552) was diagnostic
for Plateosaurus engelhardti back in the 1830s, as is also the situation for the
holotypes of many other dinosaurian taxa erected during the early years of Linnaean
taxonomy. He suggested that addressing these problems in the manner suggested by
this application ‘would likely result in chaotic changes in zoological nomenclature.’
However, comparable petitions for taxa from the Victorian era (1837–1901) based on
currently indeterminate holotypes would, as in the case of Plateosaurus engelhardti,
bring clarification rather than chaotic changes and, in addition, bring these dinosaurian
taxa in line with the taxonomic realities of the 21st century. He also argued that,
because of the indeterminate nature of the lectotype of Plateosaurus engelhardti,
another species should be proposed as the type species of the genus Plateosaurus,
rather than the designation of a neotype, in order to preserve the generic name.
Galton & Kermack (2010) recognized four species of Plateosaurus: P. gracilis, P.
ingens, P. longiceps and P. trossingensis, with P. engelhardti and P. erlenbergiensis as
nomina dubia. The sacrum of Plateosaurus engelhardti is readily distinguishable from those of the Swiss P. ingens and of P. gracilis (see Galton, 1986, 1984b, 1999; Moser,
2003). Yates (2003) referred Sellosaurus gracilis Huene, 1908 (lower Löwenstein
Formation, Germany) to Plateosaurus as P. gracilis (Huene, 1908) because the
differences from P. engelhardti as exemplified by SMNS 13200 were slight. However,
Yates (2007) has P. gracilis as the sister taxon to the more recent P. engelhardti and
P. ingens, so gracilis should revert back to Sellosaurus gracilis Huene, 1908 as
Plateosaurus longiceps Jaekel, 1913 (June) from near Halberstadt has priority over
P. trossingensis Fraas, 1913 (November) from Trossingen, the other well represented
species from the Trossingen Formation of Germany. However, the holotype of P.
trossingensis (SMNS 13200) is an almost complete skeleton (versus skull MB R.1937
for P. longiceps) and it has been extensively illustrated in the literature as Plateosaurus.
The hypodigm (= specimens available for study) for P. trossingensis is very much
more extensive than that for P. longiceps (details in Galton, 2001a; Schoch, 2011),
with numerous articulated skeletons, several of which have complete skulls (Galton,
1984a, 1985a, 2001a; Weishampel & Westphal, 1986; Prieto-Márquez & Norell, 2011;
Schoch, 2011). In addition, the SMNS has been excavating the reopened type
Trossingen quarry since 2007 (Schoch, 2011) whereas the type Halberstadt quarry
was built over in the 1940s.
Yates (2003, p. 331) considered the syntypes of Plateosaurus engelhardti as being
inadequate for diagnosis, so he treated ‘SMNS 13200 as the unofficial holotype of P.
engelhardti, while recognizing that this decision will need to be ratified by the ICZN.’
This usage is formalized in Case 3560 but, if preservation of the genus Plateosaurus
requires the designation of a new type species, rather than a neotype, then the
International Commission on Zoological Nomenclature is accordingly asked instead:
(1) to use its specific powers as granted by Article 78.2.3 to include in its Opinion
on the present Case (cf. Article 80.2.1) a confirmation that the generic name
Plateosaurus and the name of its type species, P. engelhardti, are both available
from Meyer (1837);
(2) to use its plenary power to set aside all previous fixations of type species for the
nominal genus Plateosaurus Meyer, 1837 and to designate Plateosaurus
trossingensis Fraas, 1913 as the type species;
(3) to place on the Official List of Generic Names in Zoology the name
Plateosaurus Meyer, 1837 (gender: masculine), type species Plateosaurus
trossingensis Fraas, 1913, as ruled in (2) above;
(4) to place on the Official List of Specific Names in Zoology the name
trossingensis Fraas, 1913, as published in the binomen Plateosaurus trossingensis
Fraas, 1913 (specific name of the type species of Plateosaurus Meyer, 1837,
as ruled in (2) above).
As regards the original petition, it should be noted that it is Heroldsberg (Berg: castle;
not Burg: mountain) and Nürnberg (or Nuremberg, not Nüremberg), the Universität
Erlangen did not become Universität Erlangen-Nürnberg until about 1970, and ‘by
monotypy’ should be deleted in section 14 (3). Concerning the Comment by
Demirjian (BZN 69: 295–296), the last sentence should read ‘Given the risks of
nomenclatural instability resulting from abandoning use of the name Plateosaurus, I
strongly support the proposals in Case 3560.’