Friday, December 14, 2012

Sternum

Here is some material on the sternum:

DINOSAURS
Tyrannosaurs - sternum not suitable for flight
Compsognathus -sternum not suitable for flight?
Ornitholestes - sternum not suitable for flight
Therizinosaur - sternum not suitable for flight?

Deinonychus - sternum not suitable for flight
Dromaeosaurus - sternum not suitable for flight
Utahraptor - sternum not suitable for flight

BIRDS
Bambiraptor* - sternum suitable for flight
Alvarezsaurs** - sternum suitable for flight
Microraptor - sternum suitable for flight
Velociraptor - sternum suitable for flight?
Ornithothoraces (Hesperornithes, Presbyornithids, Confuciusornithids, Ichthyornithes) - sternum suitable for flight

Pterosaur - sternum suitable for flight


*  http://en.wikipedia.org/wiki/Bambiraptor
Bambiraptor had quite a few features in common with modern birds. It had a wishbone, something all modern birds have that allow them to flap their wings, and its arms and hands were very long for its body size. In fact, the length of its arms and hands approached the lengths needed for flight. It also had an ossified sternum, a bone that is essential for birds to be able to move their wings for flying. Even with these similarities, however, there is no doubt that Bambiraptor was still a dinosaur from the raptor family. It had the killer claw on its foot like Velociraptor, and it had a mouth full of sharp teeth. It is considered by many to be the North American version of Archaeopteryx. Clearly a short step away from its European relative, this specimen is an exceptionally important piece of the bird/dinosaur puzzle. With more than 90 percent of the animal discovered, along with the remains of what may be a second individual, this specimen will continue to provide insight into the evolution of birds.
**  http://en.wikipedia.org/wiki/Alvarezsauridae
These mistaken [actually correct] assignments of alvarezsaurs to birds were caused primarily by features that are strikingly, or even uniquely, avian. The sternum, for example, is elongated and deeply keeled for an enlarged pectoralis muscle, as it is in neognathous birds and volant ratites. One bone in the skull of Shuvuuia appeared to be an ectethmoid fused to a prefrontal. The ectethmoid is an ossification known only in Neornithes. Other birdlike characters included the palatine, foramen magnum, cervical and caudal vertebrae, and many others.[9]
Metornithes
  • Alvarezsauria
  • Aviremigia

A comparison of bird, pterosaur and
bat skeletal structure, focusing on the sternum.


Dinosaurs do not have a sternum suitable for flying.
Metornithes (Alvarezsauria + Aviremigia) have a sternum suitable for flying.
Pterosaurs have a sternum suitable for flying.

We can see there is no relationship of dinosaurs to primitive birds. 
There is a relationship with pterosaurs.



7 comments:

  1. Notice in the list I have presented, that dinosaurs do not have the form of sternum suitable for flying while all members of Metornithes do.

    And so do pterosaurs.

    In the dino to bird theory, unique novelties appear out of the blue, at some unknown time, in some unknown creature.
    In the pterosaur to bird theory the precursors are already present.

    ReplyDelete
  2. http://paleodb.org/cgi-bin/bridge.pl?action=checkTaxonInfo&taxon_no=58909&is_real_user=1
    "Taxonomy
    Metornithes was named by Perle et al. (1993). It was considered monophyletic by Ji et al. (1999).

    It was assigned to Ornithothoraces by Perle et al. (1993); to Aves by Chiappe et al. (1996); to Avialae by Perle et al. (1994), Novas (1996) and Novas (1997); to Aves by Forster et al. (1996), Ji et al. (1999) and Holtz (2000); and to Maniraptora by Novas and Agnolin (2004)."

    ReplyDelete

  3. It may be more precise to say that there is no connection between the dinosaurs and Metornithes.

    http://en.wikipedia.org/wiki/Metornithes
    "In 1993, Perle and colleagues coined the name Metornithes to include alvarezsaurids and modern birds, which the researchers believed were members of the Avialae."

    http://en.wikipedia.org/wiki/Alvarezsauridae
    "These mistaken [actually not mistaken] assignments of alvarezsaurs to birds were caused primarily by features that are strikingly, or even uniquely, avian. The sternum, for example, is elongated and deeply keeled for an enlarged pectoralis muscle, as it is in neognathous birds and volant ratites. One bone in the skull of Shuvuuia appeared to be an ectethmoid fused to a prefrontal. The ectethmoid is an ossification known only in Neornithes. Other birdlike characters included the palatine, foramen magnum, cervical and caudal vertebrae, and many others.[9]"

    ReplyDelete

  4. http://en.wikipedia.org/wiki/Bambiraptor
    "Bambiraptor had quite a few features in common with modern birds. It had a wishbone, something all modern birds have that allow them to flap their wings, and its arms and hands were very long for its body size. In fact, the length of its arms and hands approached the lengths needed for flight. It also had an ossified sternum, a bone that is essential for birds to be able to move their wings for flying. Even with these similarities, however, there is no doubt that Bambiraptor was still a dinosaur from the raptor family. It had the killer claw on its foot like Velociraptor, and it had a mouth full of sharp teeth. It is considered by many to be the North American version of Archaeopteryx. Clearly a short step away from its European relative, this specimen is an exceptionally important piece of the bird/dinosaur puzzle. With more than 90 percent of the animal discovered, along with the remains of what may be a second individual, this specimen will continue to provide insight into the evolution of birds."

    It says:
    "there is no doubt that Bambiraptor was still a dinosaur from the raptor family."
    Not correct. It is from the raptor family but not a dinosaur.

    ReplyDelete
  5. Summary:

    Dinosaurs:
    Tyrannosaurs, Compsognathus, Ornitholestes, Therizinosaur

    Birds:
    Paraves, Alvarezsaurids, Oviraptors (secondarily flightless), Ornithomimids (secondarily flightless)

    ReplyDelete
  6. Another reference to bats. How much evidence do you need?

    El Perro

    ReplyDelete
  7. http://en.wikipedia.org/wiki/Mononykus
    "Mononykus is currently represented by a single holotype specimen, catalog number IGM N107/6. This specimen consists of a partial skeleton lacking a tail, and only small fragments of skull bones, including a complete braincase."

    http://www.geol.umd.edu/~tholtz/G104/lectures/104coelur.html
    In the Cretaceous Alvarezsauridae, the forelimbs are further transformed into bizarrely poweful arms with a huge thumb claw and exceedingly small digits II and III. The alvarezsaurids have a backwards pointing pubis. Unlike the therizinosauroid and ornithischian situation, this backwards position of the pubis is more likely associated with changes in the locomotory muscles towards knee-driven power from the ancestral tail-and-femur driven power.

    ReplyDelete