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Re: Andesaurus redescribed



Nice to see that _Giraffatitan_ is gaining traction as a valid genus,
rather than being lumped in with _Brachiosaurus_.

Also, the paper mentions a new genus for an old (very old) named
species of British sauropod (Hulke, 1874).  Although attributed to
Barrett et al. (2010), the paper is given as "in press", so it would
be prudent to keep mum on the new genus until the paper is officially
'out'.  There's already enough nomina nuda floating around in
cyberspace....


Cheers

Tim



On Sat, Mar 5, 2011 at 3:24 AM, bh480@scn.org <bh480@scn.org> wrote:
> From: Ben Creisler
> bh480@scn.org
>
> A new advance online paper in the Zoological Journal of the Linnean Society:
>
> PHILIP D. MANNION and JORGE O. CALVO (2011)
> Anatomy of the basal titanosaur (Dinosauria, Sauropoda) Andesaurus delgadoi
> from the mid-Cretaceous (Albian–early Cenomanian) Río Limay Formation,
> Neuquén Province, Argentina: implications for titanosaur systematics.
> Zoological Journal of the Linnean Society
> Early View (Articles online in advance of print)
> DOI: 10.1111/j.1096-3642.2011.00699.x
> http://onlinelibrary.wiley.com/doi/10.1111/j.1096-3642.2011.00699.x/abstract
>
> Titanosauria is a taxonomically and morphologically diverse clade of
> sauropod dinosaurs that appeared in the Middle Jurassic and radiated in the
> mid–Late Cretaceous; however, its intrarelationships are poorly understood.
> The mid-Cretaceous Argentinean sauropod Andesaurus delgadoi has repeatedly
> been recovered at the base of Titanosauria, and thus represents a crucial
> taxon for determining the evolutionary history of this clade; yet it has
> only received a brief description. Here, we re-describe the holotype,
> comprising dorsal, sacral, and caudal vertebrae, as well as limb and pelvic
> elements. Detailed comparisons are made with a global array of
> titanosauriforms. Andesaurus is a valid genus and can be diagnosed by five
> autapomorphies: (1) posterior dorsal neural spine height greater than twice
> centrum height (autapomorphic within Macronaria); (2) square-shaped
> anterior–middle caudal centra in lateral view; (3) anteroposteriorly
> elongate fossa present on the anterodorsal corner of the lateral surface of
> middle–posterior caudal centra; (4) ridge along the midshaft of the ventral
> surface of metacarpal I, close to the ventromedial margin; (5) prominent
> ventromedial ridge along the distal half of metacarpal V. Other remains
> previously attributed to Andesaurus cannot be referred to this genus.
> Sixteen putative titanosaur synapomorphies can be recognized in Andesaurus,
> including: (1) lateral pneumatic foramina in dorsal vertebrae situated
> within fossae; (2) anterior–middle caudal vertebrae with ventrolateral
> ridges either side of a ventral midline hollow; and (3) lateral bowing of
> metacarpal I. This revision provides an important foundation for future
> phylogenetic analyses of titanosaurs, and adds to our growing understanding
> of this enigmatic clade. Lastly, we recommend the disuse of the coordinated
> suprageneric rank taxa of Andesaurus (Andesaurinae, Andesauridae, and
> Andesauroidea), at least until titanosaur intrarelationships are better
> elucidated.
>
>
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