[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Hadrosaurus and Claosaurus revised diagnoses



On Fri, Feb 25, 2011 at 3:13 PM, Brad McFeeters
<archosauromorph2@hotmail.com> wrote:
>
> What was the original content of Hadrosauria Huene 1908?

>From Prieto-Marquez (2010):

     von Huene (1908; 1956) erected the name Hadrosauria
     to include hadrosaurids and all those forms
     that were morphologically more similar to them than
     to Iguanodon. Hadrosauria included the following
     families: Prohadrosauridae, Hadrosauridae, Saurolophidae,
     Cheneosauridae and Lambeosauridae. In
     the Prohadrosauridae, von Huene included relatively
     basal forms such as Telmatosaurus and Tanius.
     Within Hadrosauridae, he included ‘Ornithotarsus’
     Cope, 1869, along with ‘flat-headed’ or ‘low-crested’
     taxa such as ‘Thespesius’ Leidy, 1856b (= Edmontosaurus
     annectens Marsh, 1892), ‘Anatosaurus’
     Lull & Wright, 1942 (= E. annectens), Edmontosaurus,
     ‘Mandschurosaurus’ Riabinin, 1930 (= Gilmoreosaurus
     Brett-Surman, 1979, in part), Kritosaurus
     (= Kritosaurus navajovius Brown 1910 and Gryposaurus
     spp.) and Brachylophosaurus Sternberg, 1953.
     The Saurolophidae was composed of Saurolophus,
     Prosaurolophus, and Bactrosaurus. As in Lull &
     Wright (1942), the Cheneosauridae included the
     small (juvenile lambeosaurine) forms ‘Cheneosaurus’
     Lambe, 1917a and ‘Procheneosaurus’ Matthew, 1920.
     Finally, von Huene’s Lambeosaurinae was equivalent
     to the Lambeosaurinae of other authors, in that it
     included those hadrosaurs with large hollow crests,
     such as Lambeosaurus, Corythosaurus, Hypacrosaurus,
     and Parasaurolophus. However, von Huene also
     considered as ‘lambeosaurids’ ‘Trachodon’, Jaxartosaurus
     Riabinin, 1939, and Nipponosaurus Nagao, 1936.

More recently, Hadrosauria has also been used (though not defined) by
Horner, who proposed a diphyletic origin for traditional hadrosaurids.
 Under his scheme, Hadrosauria included Hadrosauridae and _Iguanodon_,
whereas his new taxon Lambeosauria included Lambeosauridae and
_Ouranosaurus_; and Hadrosauria and Lambeosauria were sister taxa
within Iguanodontoidea.  This diphyletic 'baggage' for the name
Hadrosauria may explain why it has not yet been co-opted and defined
for a clade - although this in itself is not a good reason.

IMHO, Hadrosauria seems the perfect choice for the clade that
Prieto-Marquez calls 'Hadrosauridae'.  The complication would be if
Euhadrosauria (a clade proposed by Weishampel &c in 1993) is defined
such that it might be more inclusive than Hadrosauria... which would
be embarrassing.  Curiously, Prieto-Marquez (2010) rejects the
validity of the name Euhadrosauria according to ICZN rules: "Under
the International Code of Zoological Nomenclature... any taxon less
inclusive than a taxon in the family rank group is a subfamily, tribe,
subtribe, genus, or species (Article 35.1)."  Yet, he goes on to
include Saurolophidae inside Hadrosauridae: "I considered it more
preferable to stretch the ICZN rules by nesting a family name within a
family name rather than violting (sic) them by using an unranked taxon
within a family."  Other unranked taxa have appeared below the
family-level (e.g., Brachyrostra, between 'subfamily' and 'tribe'
within Carnotaurinae), and frankly I don't see the problem with this
practice.


Cheers

Tim