Wednesday, December 17, 2014

Pubis evolution


http://pterosaurheresies.files.wordpress.com/2011/09/prepubes588.jpg
Pterosaur pubis (in green) and prepubis (in yellow). The drawing of MPUM 6009 is the most relevant.




The pterosaur pubis (green) is homologous with the basal paraves superior pubic ramus and pubic body.
The pterosaur prepubis (yellow) is homologous with the basal paraves inferior pubic ramus.


http://archosaurmusings.wordpress.com/2009/12/24/back-to-that-pterosaur-sacrum-pelvis/
pterosaurs also have a fourth pelvic bone in the form of the pre-pubis. This pair of bones (one for each side) lie, and no points for guessing this, in front of, and articulate with, the pubes.
http://pterosaurheresies.wordpress.com/tag/pterosaur-evolution/page/6/
The prepubis of pterosaurs is a pelvic bone not found in the vast majority of tetrapods. It is not homologous with the prepubis of monotremes and marsupials. Nor is it homologous with the so-called “prepubic” bones of crocodilians, which are homologous with the pubic bones of other amniotes (Seeley 1901). The prepubis of ornithischian dinosaurs is a process of the pubis and not a separate ossification.
For example:
The pubis/prepubis parts of MPUM 6009 above, correspond to the 3 parts of the paraves pubis, as seen in the oviraptor pubis in drawing "C" below. 

http://qilong.files.wordpress.com/2011/07/caenagnathid-ilia.jpg?w=932&h=549




Sunday, December 14, 2014

Feet

Pterosaur feet are like basal paraves feet. Dinosaur feet are not like basal paraves feet.

ivpp.cas.cn/qt/papers/201403/P020140314393548274893.pdf
Distally the [Epidendrosaurus] trochlea of metatarsal I aligns with those of II and III as in advanced perching birds, but not in other known dinosaurs.
The foot of Epidendrosaurus [a Scansoriopterygidae] is unique among nonavian
theropods. Although it does not preserve a reversed
hallux, metatarsal I is articulated with metatarsal II at
such a low position that the trochleae of metatarsals I–IV
are almost on the same level (see Figs. 1, 2d), which
is similar to those of perching birds including the Early
Cretaceous flying birds Sinornis (Sereno 1992) and
Longipteryx (Zhang and Zhou 2001), as well as many arboreal
pterosaurs.
http://en.wikipedia.org/wiki/Scansoriopteryx
It [Scansoriopteryx] also had an unusually large first toe, or hallux, which was low on the foot and may have been reversed, allowing some grasping ability.[1]
The Scansoriopterygidae are among the most basal members of Paraves.


http://www.nature.com/nature/journal.../391886a0.html
Other features of digits I-IV of the D. weintraubi foot indicate a capacity for grasping that is consistent with an ability to climb but is unexpected in an obligate cursor. The claws are moderately curved (nearly as strongly as the claws of the manus); all phalanges except the most proximal have well developed flexor tubercles for the insertion of digital flexors (Fig. 2); and all of the IP joints allow for extensive flexion of the digits (as exhibited by digit IV; Fig. 2). Furthermore, the phalangeal proportions of the digits of Dimorphodon and other basal pterosaurs are similar to those of birds with grasping feet (that is, perching, climbing, and raptorial species) and unlike those of primarily ground-living birds, bipedal dinosaurs and the primitive dinosauromorphs Lagerpeton and Marasuchus.

Friday, December 12, 2014

Notable

http://www.ivpp.ac.cn/qt/papers/201206/P020120604508520389814.pdf
The [Epidendrosaurus] material described in this paper was collected from a new locality, Daohugou, in east Nei Mongol, northeast China, which is west of Liaoning Province. Many salamanders(Wang 2000), plants and insects (Zhang 2002)have recently been discovered from this new locality. It is notable that an anurognathid rhamphorhynchoid pterosaur [Jeholopterus] with beautiful hair [pycnofibers] covering the whole body has also been reported from this locality (Wang et al. 2002). The estimated age of the deposit at this locality is very controversial and ranges from the Middle Jurassic or the Early Cretaceous according to various authors (Wang etal. 2000; Zhang 2002); however, most workers currently regard it as being Late Jurassic.
Epidendrosaurus is a Scansoriopterygidae and one of the most basal members of Paraves.


http://link.springer.com/article/10.1360/02tb9054#page-1
We report a new and nearly completely articulated rhamphorhynchoid pterosaur, Jeholopterus ningchengensis gen. et sp. nov., with excellently preserved fibres in the wing membrane and “hairs” in the neck, body and tail regions.
https://scholar.google.com/scholar_lookup?title=A+nearly+completely+articulated+rhamphorhynchoid+pterosaur+with+exceptionally+well-preserved+wing+membranes+and+%22hairs%22+from+Inner+Mongolia,+northeast+China&author=WANG+X&author=ZHOU+Z&author=ZHANG+F&author=XU+X&publication_year=2002&journal=Chin+Sci+Bull&volume=47&pages=226-230


http://en.wikipedia.org/wiki/Jeholopterus
Jeholopterus was a small anurognathid pterosaur from the Middle to Late Jurassic[1]Daohugou Beds of the Tiaojishan Formation of Inner MongoliaChina , preserved with hair-like pycnofibres and skin remains.

http://en.wikipedia.org/wiki/Yi_%28dinosaur%29
The only known Yi qi fossil was found in rocks assigned to the Tiaojishan Formation, dating to the Callovian-Oxfordian age of the Middle-Late Jurassic,[1] dated to between 165 and 153 million years ago.[3] This is the same formation (and around the same age) as the other known scansoriopterygids Epidexipteryx and Scansoriopteryx.

Yi qi





Monday, December 8, 2014

Vocabulary

It needs to be kept in mind that the vocabulary that is routinely used in discussing the origin of birds is based on the dino to bird theory. The vocabulary is not neutral. It assumes the dino to bird theory*.
This makes it tricky to even describe the pterosaur to bird theory. You have to use very qualified expressions, which even then, imply a dino to bird theory.
For example, I often use the phrase "basal paraves". This is intended to mean the long-bony-tailed feathered flying and secondarily flightless creatures. For example, Scansoriopterygidae.
But the category "paraves" is defined WITHIN the dino to bird theory. It assumes the dino to bird theory. So I obviously do not mean to include the baggage that the term "paraves" carries within the dino to bird theory.
For example, I do not mean that basal paraves evolved from dinosaurs and I do not mean to exclude oviraptors from the paraves group.


* for example consider this:
http://en.wikipedia.org/wiki/Paraves
Paraves is a branch-based clade defined to include all dinosaurs which are more closely related to birds than to oviraptorosaurs.