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RE: Neovenatoridae and Megaraptora: now it can be told!



I performed a heuristic analysis with the data matrix of Benson et al. (2009) 
and it seems that the clade of Megalosauroidea which includes Monolophosaurus, 
this monophyletic group with Xuanhanosaurus, Marshosaurus, Piatnitzkysaurus and 
Condorraptor, and another monophyletic group with the Spinosauridae and 
(according to me) the Megalosauridae is not well-supported. The Megalosauroidea 
might only be the Spinosauridae + the Megalosauridae. I should see what 
characters link Monolophosaurus with the Spinosauridae and the 
"Megalosauridae". Unfortunaltely, I haven't got the program to check this.
Besides, We still have to wait for another paper of Carrano, Benson and Sampson 
on the Megalosauroidea.


This is what I found with a 50% Majority-rule consensus of 1029 trees :

+--Neotetanurae
 `------55-------+-100-+--Xuanhanosaurus
        ^        |     `-100-+--Marshosaurus
        |        |           `-100-+--Condorraptor
Megalosauroidea  |                 `--Piatnitzkysaurus
                 `-55-+--Monolophosaurus
                      `-100-+--Spinosauridae
          Megalosauridae?-> `-94-+-73-+--Eustreptospondylus
                                 |    `-87-+--Magnosaurus
                                 |         `--Streptospondylus
                                 `-55-+--Piveteausaurus
                                      `-52-+--Duriavenator
                                           `-64-+-88-+--Afrovenator
                                                |    `--Dubreuillosaurus
                                                `-89-+--Megalosaurus
                                                     `--Torvosaurus


Christophe Hendrickx
http://spinosauridae.fr.gd/





> Date: Fri, 16 Oct 2009 12:00:41 -0400
> From: tholtz@umd.edu
> To: dinosaur@usc.edu
> Subject: Neovenatoridae and Megaraptora: now it can be told!
> 
> Just out in Early View on Naturwissenschaften (and I'm so glad I can
> publically talk about this now!):
> 
> Benson, R.B.J., M.T. Carrano & S.L. Brusatte. 2009. A new clade of archaic
> large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to
> the latest Mesozoic. Naturwissenschaften doi:10.1007/s00114-009-0614-x
> Abstract  Non-avian theropod dinosaurs attained large body sizes,
> monopolising terrestrial apex predator niches in the Jurassic-Cretaceous.
>>From the Middle Jurassic onwards, Allosauroidea and Megalosauroidea
> comprised almost all large-bodied predators for 85 million years. Despite
> their enormous success, however, they are usually considered absent from
> terminal Cretaceous ecosystems, replaced by tyrannosaurids and abelisaurids.
> We demonstrate that the problematic allosauroids Aerosteon, Australovenator,
> Fukuiraptor and Neovenator form a previously unrecognised but ecologically
> diverse and globally distributed clade (Neovenatoridae, new clade) with the
> hitherto enigmatic theropods Chilantaisaurus, Megaraptor and the
> Maastrichtian Orkoraptor. This refutes the notion that allosauroid
> extinction pre-dated the end of the Mesozoic. Neovenatoridae includes a
> derived group (Megaraptora, new clade) that developed long, raptorial
> forelimbs, cursorial hind limbs, appendicular pneumaticity and small size,
> features acquired convergently in bird-line theropods. Neovenatorids thus
> occupied a 14-fold adult size range from 175 kg (Fukuiraptor) to
> approximately 2,500 kg (Chilantaisaurus). Recognition of this major
> allosauroid radiation has implications for Gondwanan paleobiogeography: The
> distribution of early Cretaceous allosauroids does not strongly support the
> vicariant hypothesis of southern dinosaur evolution or any particular
> continental breakup sequence or dispersal scenario. Instead, clades were
> nearly cosmopolitan in their early history, and later distributions are
> explained by sampling failure or local extinction.
> 
> Includes MAJOR new phylogentic analyses (combining the ongoing work of the
> three authors).
> 
> Neovenatoridae includes Neovenator, Chilantaisaurus, and Megaraptora. The
> latter is a clade of gracile forms including Megaraptor, Fukuiraptor,
> Australovenator, Aerosteon, and (Maastrichtian) Orkoraptor.
> 
> Neovenatoridae is the sister taxon to Carcharodontosauridae in a larger
> Carcharodontosauria (= "Carcharodontosauridae" as I used it in Dinosauria
> II).
> 
> Other tidbits in the phylogenetic analysis in the supplementary data:
> Sinraptoridae includes Lourinhasaurus, Poekilopleuron, and
> Metriacanthosaurus.
> 
> Megalosauroidea (aka Spinosauroidea) has the following structure (once
> Chuandongocoelurus and Pivetausaurus are a posteriori deleted):
> +--Neotetanurae
> `--+--+--Xuanhanosaurus
>    |  `--+--Marshosaurus
>    |     `--+--Condorraptor
>    |        `--Piatnitzkysaurus
>    `--+--Monolophosaurus
>       `--+--Spinosauridae
>          `--+--+--Eustreptospondylus
>             |  `--+--Magnosaurus
>             |     `--Streptospondylus
>             `--+--Duriavenator
>                `--+--+--Afrovenator
>                   |  `--Dubreuillosaurus
>                   `--+--Megalosaurus
>                      `--Torvosaurus
> 
> I've known about this analysis for awhile and am very happy to see it out,
> but (I'm sure) not as much as the authors.
> 
> Congratulations on a very interesting study!
> 
> Thomas R. Holtz, Jr.
> Email: tholtz@umd.edu Phone: 301-405-4084
> Office: Centreville 1216                      
> Senior Lecturer, Vertebrate Paleontology
> Dept. of Geology, University of Maryland
> http://www.geol.umd.edu/~tholtz/
> Fax: 301-314-9661             
> 
> Faculty Director, Earth, Life & Time Program, College Park Scholars
> http://www.geol.umd.edu/~jmerck/eltsite/
> Faculty Director, Science & Global Change Program, College Park Scholars
> http://www.geol.umd.edu/sgc
> Fax: 301-314-9843
> 
> Mailing Address:      Thomas R. Holtz, Jr.
>                       Department of Geology
>                       Building 237, Room 1117
>                       University of Maryland
>                       College Park, MD 20742 USA
> 
                                          
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