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Relatively New Refs (long)



The university's biological library here has Naturwissenschaften. I've had a
look into it for the first time a few days ago, et voilà --

J.-D. Lim, L. D. Martin*, K.-S. Baek: The first discovery of a brachiosaurid
from the Asian continent, Naturwissenschaften (2001) 88:82-84; published
online (no idea where): 21 February 2001

*What? Larry D. "birds have croc teeth" Martin? ~:-|

"_Abstract_ Described here is a sauropod tooth from the Early Cretaceous of
South Korea, similar to *Brachiosaurus*. The crown of the tooth is beveled
off lingually so that when worn it presents a chisel-like edge. This find
confirms the presence of a brachiosaurid in East Asia during the Early
Cretaceous. [...] An isolated sauropod dinosaur tooth was collected from the
lacustrine Early Cretaceous (Barremian-Aptian) Jinju formation (shale
facies) in the Kyongsang supergroup of South Korea."

The tooth is (fortunately) not named. Comparisons are made with
*Brachiosaurus*, *Camarasaurus*, *Pleurocoelus*, *Euhelopus* and
*Asiatosaurus*. This tooth differs from all but is most similar to those of
*Brachiosaurus*.

"This discovery of KS 7002 is the first report of a brachiosaurid from the
asian continent" -- *Ultrasaurus* is not mentioned.

Now hold your breath --

D. J. Gower: Possible postcranial pneumaticity in the last common ancestor
of birds and crocodilians: evidence from *Erythrosuchus* and other Mesozoic
archosaurs, Naturwissenschaften (2001) 88:119-122; published online: 27
February 2001

Pneumatic fossae and foramina are found on neural arches throughout
Archosauria, and maybe beyond. Fig. 1 represents the following cladogram
(which lines up in Times New Roman):

Vertebral pneumaticity:
O absent
X present
? unknown

--+-- ? Rhynchosauria
    `--+-- ? Proterosuchidae
         `--Archosauria
              |-- X *Erythrosuchus*
              `--+-- ? *Euparkeria*
                   `--+-- ? Proterochampsidae
                        `--crown-group Archosauria
                             |--+-- X/? phytosaurs
                             |     `--Suchia
                             |          |-- X *"Mandasuchus"*
                             |          |-- ? aetosaurs
                             |          `--+-- X *Batrachotomus*
                             |               `--+-- X *Postosuchus*
                             |                    `--+-- X/? sphenosuchians
                             |                         `-- O crocodilians
                             `--Ornithodira
                                   |-- X Pterosauria
                                   `--*== X/O non-avian dinosaurs
                                        `-- X birds

"[...] This reconstruction is very preliminary. Important caveats include
uncertainty surrounding suchian phylogeny, use of parsimony in ancestral
character state reconstruction, assumptions that features documented in the
text are indicative of vertebral pneumaticity, inadequate understanding of
archosaur pneumaticity, incomplete knowledge of vertebral morphology in
several taxa, and the crude construction of the 'vertebral pneumaticity'
character considered here."

Means, if someone finds pneumatic vertebrae in a proterosuchid, a
rhynchosaur and a prolacertiform, pterosaurs can be prolacertiforms and
their air-sac system can be still homologous with that of dinosaurs. :-o

"One of the several distinct anatomical features of extant birds is a system
of respiratory airsacs, diverticula of which [...]. The osteological
correlates of these avian airsac diverticula have been characterized (Britt
1997), and similar structures have long been known in the vertebrae of
pterosaurs and dinosaurs (Meyer 1837; Owen 1856; Seeley 1870). Given these
observations, postcranial pneumaticity can be mapped onto a currently
orthodox hypothesis of archosaur phylogeny (Fig. 1), and inferred to have
been present in the ancestral ornithodiran (Britt 1997). The other extant
group of archosaurs, crocodilians, lack postcranial airsacs and associated
osteological correlates, and this has been considered or implied to be a
retained plesiomorphy. Additionally, pneumatic vertebrae are reported to be
restricted to ornithodirans among archosaurs (e. g. Britt 1997). Here I
report possibly pneumatic vertebrae in an extinct non-crown-group archosaur,
and in at least some taxa more closely related to crocodilians than to
birds. This has important implications for the understanding of the
evolution of archosaurian pneumaticity and respiration, and of methods with
which to best analyse the evolutionary biology of features in pairs of
taxa."

*Erythrosuchus africanus* has camerate neural arches on the proximal
cervical and cranial dorsal vertebrae. "Unlike in many ornithodirans, the
centra of *E. africanus* vertebrae appear to be apneumatic." Very convincing
illustrations.

"Similar possibly pneumatized presacral neural arches are also present in
the rauisuchians *'Mandasuchus tanyauchen'* [...], *Batrachotomus
kupferzellensis* [...] and *Postosuchus kirkpatricki* [...] -- i. e. at
least some of the Mesozoic archosaurs more closely related to crocodilians
than birds [...]. The presence in rauisuchians of neural arch lamellae has
been previously dismissed as a convergence shared with ornithodirans (Wilson
1999). Neural arch fossae separated by lamellae are also present in
phytosaurs (Camp 1930) and sphenosuchian crocodylomorphs (Crush 1984; Walker
1990), while pits at the base of neural spines are present in at least one,
but not all, species of [...] Rhynchosauria (Dilkes 1995). Clearly a
diversity of fossil diapsids and potentially pneumatic features need to be
reassessed, and the criteria for identifying pneumaticity re-evaluated."

"The internal sinuses of the vertebrae of *E. africanus* and non-crocodilian
suchians are poorly known, but the overall extent of pneumatization, if
correctly identified, is clearly not as strongly developed as in the
camellate vertebrae of [e. g.] tetanuran theropods, including birds."

"[...] it now seems that although pneumatized centra might be restricted to
Ornithodira, pneumatized vertebrae per se may not be a uniquely derived
feature grouping birds with other dinosaurs and pterosaurs, and absence of
pneumaticity in extant crocodilians (and some dinosaurs) might be derived
relative to the archosaur groundplan."

"The presence of vertebral pneumaticity in non-crown-group and basal suchian
archosaurs suggests that presence alone of similar pneumaticity in non-avian
theropods should be used carefully in debates on lung ventilation mode in
these taxa. From a Recent perspective, the current fossil evidence indicates
that derived features of an avian-like lung were perhaps to some extent
present in the last common ancestor of birds and crocodilians."

"The previous use of crocodilians as an outgroup demonstrating the
derivedness of avian morphology is misleading because both avian and
crocodilian anatomy is a combination of plesiomorphies and apomorphies with
respect to their last common ancestor. In an analogous situation, Gower and
Weber (1998) showed how detailed similarities between bird and crocodilian
braincases can be demonstrated to be independently acquired when the
morphology of a wide range of fossil archosaurs both from within and outside
the crown group is examined."

And the wisest of all -- :-)
"Further research of this kind is now required on archosaur postcranial
pneumaticity."