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Dinosaur Genera List corrections #63



Thanks to Tracy Ford, who attended the symposium, a mighty tome chock-full of
dinosaur lore arrived here this past Monday. I've scarcely begun to plumb its
depths, but a quick scan for new dinosaur taxa and other nomenclatural
oddments revealed the following information.

First, the tome itself:

Morales, M., ed., 1996. The Continental Jurassic, Transactions of the
Continental Jurassic Symposium, October 21-23, 1996, Museum of Northern
Arizona, Flagstaff, Arizona, Museum of Northern Arizona Bulletin #60: [x] +
xvi + 588 pp.

I guess it may be ordered from the Museum of Northern Arizona, 3101 North
Fort Valley Road, Flagstaff, Arizona 86001. ISBN 0-89734-119-8. Sorry, cover
price is not available. I count 82 articles listed the contents pages, so
they average somewhat more than 7 pages in length. All aspects of the
Jurassic are covered, with major sections on dinosaurs, other vertebrates,
paleontology, sedimentology, stratigraphy, and so forth. The articles are
fairly specialized, so the book isn't for everyone.

One piece is a rare technical paper from Robert Bakker:

Bakker, R. T., 1996. "The Real Jurassic Park: Dinosaurs and Habitats at Como
Bluff, Wyoming," in Morales, ed., 1996: 35-49.

He notes, among other things, that the stegosaur Diracodon was more primitive
than Stegosaurus and that Gilmore incorrectly referred the species
Stegosaurus stenops to that genus. Since I largely followed Gilmore and
Bakker in my stegosaur reviews for Gakken and Skullduggery in calling that
taxon ?Diracodon stenops, this is the kiss of death for that name. I'll now
refer to the species the way everyone else does, as ?Stegosaurus stenops,
retaining the question mark because of the still unresolved possibility that
it represents a genus distinct from that of Stegosaurus armatus.
Unfortunately, Bakker provides no details about why he thinks certain
stegosaur material from Como Quarry 13 should be referred to the type species
Diracodon laticeps (which does come from that quarry), or why he considers
Diracodon to have had relatively short hind limbs, etc. It's back to the
quarry maps for me to figure out what he's talking about. (The type specimen
of Diracodon laticeps is Yale Peabody Museum 1885, a pair of maxillae from a
small or juvenile ornithischian, possibly indeterminate; anything else is
referred.)

Bakker's paper also reveals a little bit about the dinosaurs Edmarka,
Brontoraptor, and Drinker, for which there is a major information drought.
Most intriguing is a citation to Hunteria volume 3:

Siegwarth, J., Linbeck, R., Bakker, R. & Southwell, B., 1996. "Giant
carnivorous dinosaurs of the family Megalosauridae," Hunteria 3: 1-77.

Haven't seen this yet, but I suspect there will be quite a bit more on
Edmarka and Brontoraptor in it when it is published.

The paper sinking Ultrasauros macintoshi as a junior subjective synonym of
Supersaurus vivianae also appears in the volume:

Curtice, B. D., Stadtman, K. L. & Curtice, L. J., 1996. "A Reassessment of
Ultrasauros macintoshi (Jensen, 1985)," in Morales, ed., 1996: 87-95.

One new taxon, a nomen nudum, introduced in this paper is Jensenosaurus
macintoshi, which the authors attribute to me. When I originally determined
that James Jensen's Ultrasaurus was a preoccupied genus, I wrote him with the
idea that I rename it after him. He nixed the idea and suggested respelling
the name to end with -os instead of -us. (Boy, was he irritated that someone
else had formally used Ultrasaurus before he had a chance to finish his
paper.) Thus was born the name Ultrasauros. This paper's authors, amusingly
enough, relate this story and even include the original generic name, thereby
making it a part of dinosaur literature.

Accordingly, we must add the genus

Jensenosaurus Olshevsky vide B. D. Curtice, Stadtman & L. J. Curtice, 1996
[nomen nudum]

to the dinosaur genera list, and bump the genera count to 798.

The following paper

Zhang Y. & Chen W., 1996. "Preliminary Research on the Classification of
Sauropods from Sichuan Basin, China," in Morales, ed., 1996: 97-107.

reveals some interesting hitherto unavailable information concerning Chinese
sauropods. The sauropod Abrosaurus, whose name and skull I had seen published
anonymously without a description in two guidebooks to the dinosaur exhibits
at the Zigong Museum, is revealed as having been described in a 1986 Master's
dissertation by a student named Ou Yanghui. Publication in a dissertation
does not constitute formal publication according to the Zoological Code, but
the authors do treat the genus as having been formally described by Ou (or
Ouyang, as they list him or her), and they illustrate the skull (nice skull,
by the way) and provide a generic diagnosis and a named type species (also
attributed to Ou), Abrosaurus gigantorhinus (different from the species name
given in the guidebooks: Abrosaurus dongpoensis). This is a grey area in
zoological nomenclature; many would regard Abrosaurus as not meeting formal
standards of publication. On the other hand, considering that a diagnosis is
provided, as well as sufficient information to identify the type specimen, I
would consider this paper to be the formal description of the genus. So we
should change the entry in the Dinosaur Genera List to read:

Abrosaurus Ou, 1986 vide Zhang & Chen, 1996

We don't change the genera count.

The paper goes on to refer several Chinese sauropod species to the genus
Mamenchisaurus and refers that genus and its earlier, less derived sister
taxon Omeisaurus to the family Mamenchisauridae. When the smoke clears, here
is the composition of the genus Mamenchisaurus:

Genus: Mamenchisaurus Young, 1954
  = Zigongosaurus Hou, Chao & Chu, 1976
  M. constructus Young, 1954 (type)
  M. hochuanensis Young & Chao, 1972
  M. fuxiensis (Hou, Chao & Chu, 1976) Zhang & Chen, 1996
    = Zigongosaurus fuxiensis Hou, Chao & Chu, 1976
  M. sinocanadorum D. A. Russell & Zheng, 1994 (not 1993)
  M. jingyanensis Zhang & Li, 1996
  M. youngsi Ou vide Zhang & Chen, 1996 [nomen nudum]

Zhang & Chen do not mention the species Mamenchisaurus sinocanadorum in their
paper. And they do not provide a reference for the species Mamenchisaurus
jingyanensis, whose type specimen is directly comparable with and closely
resembles that of Mamenchisaurus sinocanadorum; it is a new taxon to me, as
is the undescribed Mamenchisaurus youngsi, apparently another sauropod noted
or described in Ou Yanghui's dissertation. Finally, they recommend referring
the species Omeisaurus changshuoensis [sic] and Omeisaurus gongjianensis
[sic] to the genus Mamenchisaurus but do not actually employ the species
epithets in combination with the genus Mamenchisaurus. The former species
name is a misspelling of Omeisaurus changshouensis, but the latter is new to
me and does not seem to be a misspelling or new combination of any other
Chinese sauropod species. It is not described in the paper but is only
mentioned in passing. I'll treat it as a nomen nudum until I unearth a
reference or description for it. None of this affects the Dinosaur Genera
List, since the changes occur at the species level.

The following paper

Lucas, S. G., 1996. "The Thyreophoran Dinosaur Scelidosaurus from the Lower
Jurassic Lufeng Formation, Yunnan, China," in Morales, ed., 1996: 81-85.

sinks the species Tatisaurus oehleri into the genus Scelidosaurus as
Scelidosaurus oehleri, a new combination. I'll have to reread it a few times
before I'm totally convinced, but he seems to make a good case for this. This
doesn't affect the Dinosaur Genera List.