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ITALIAN LIMESTONE MEETING
Today I finished and bound AND handed in my thesis which means I
should be really happy and busy down at the pub getting the beers in.
Alas, I have too much other stuff to do and it just doesn't work like
that. Have just borrowed a copy of a new symposium volume: Renesto,
S. (ed) _Third International Symposium on Lithographic Limestones_,
Revista del Museo Civico di Scienze Naturali "Enrico Caffi",
Supplemento al Volume n. 20., pp. 136.
Results from a symposium that was held at Bergamo, Italy, from 1-5th
September 1999. Most of the papers are concerned with inverts, styles
and types of preservation and overviews of lagerstatten assemblages,
but there are a handful of tetrapod papers, some of which are
EXTREMELY interesting.
AVANZINI, M. New Anisian vertebrae tracks from the Southern Alps (Val
d'Adige and Valle di Non - Italy).
Describes and figures a bunch of trackways thought to pertain to
lepidosaurs and archosauromorphs, including possible rhynchosaur
tracks and some chirotheriids (an ichnofamily, possibly made by
things like rauisuchians). What's fascinating is some of the tracks
preserve skin impressions: for the chirotheriid prints I see that the
impression is of pebbled, non-overlapping scales (which is what we
generally expect for archosauromorph skin). Have just learnt that
there is a _Chirotherium_ ichnospecies called _C. rex_ (Peabody
1948). Another 'rex' for my list!
DAL SASSO, C. and RENESTO, S. Aquatic varanoid reptiles from the
Cenomanian (Upper Cretaceous) lithographic limestones of Lebanon.
More information on the dolichosaurid _Aphanizocnemus_ (first
monographed by Dal Sasso and Pinna in 1997) with comments on what it
might say about the affinities of snakes - discusses the distribution
of some of Lee's characters - as well as info on two new
'ophiomorph' specimens that might be basal snakes. Also some
discussion of _Pachyrhachis_ and hints that dolichosaurids, rather
than mosasaurids, might be the closest relatives of snakes. One of
the dolichosaur specimens apparently has skin preserved - would be
interesting to compare this with mosasaur skin impressions and
snakes.
NOSOTTI, S. New findings of _Tanystropheus longobardicus_ (Reptilia,
Prolacertiformes) in the Middle Triassic of Besano (Lombardy,
northern France).
New specimens, including complete juvenile skeleton and some
spectacularly well-preserved hind limbs. Amongst several new findings
regarded manus and pes structure, Nosotti emphasises that the
tanystropheid pes is quite compact and there is little potential for
abduction of digit V, as argued by Wild (1973). There are accessory
bony structures in elbow and knee joints: epiphyses or sesamoids?
Nosotti says probably epiphyses. _Tanystropheus_ is regarded as
poorly adapted for aquatic life, and designed overall for a
terrestrial existence. Maybe the constraints of the long neck
resulted in the aquatic lifestyle... but don't apply this speculation
to sauropods:)
And the most interesting paper for all you theropod nerds.....
PEREZ-MORENO, B. P. and SANZ, J. L. Theropod breathing mechanism: the
osteological evidence.
Authors assert that the methodology of Ruben et al. is questionable
and that their interpretations are doubtful: they point out that the
model lacked backing from SEM and scanning microprobe analysis. Crocs
and theropod have very different pelvic morphologies (they discuss
the mobile croc pubis). The big news is that new prepping of
_Pelecanimimus_ reveals new thoracic structures for this animal: an
enclosed thoracic box with well ossified sternal ribs articulating
with sides of sternum and thoracic ribs. The ginglymoid articulations
of the sternal and thoracic ribs indicate high kinetic ability of the
laterally flattened chest "probably associated to a costal breathing
mechanism", and costal ventilation is probably primitive for
tetrapods. "Some groups, as mammals or derived crocodilians, have
developed a singular, autapomorphic diaphragmatic lung ventilation
[sic]".
RENESTO, S., TINTORI, A., LOMBARDO, C. and MARAZZI, B. A complete
phytosaur (Reptilia, Archosauria) from the Norian (Late Triassic) of
Lombardy (northern Italy).
This specimen, which was also talked about at the last Secondary
Adaptations to Life in Water conference (Copenhagen, September 1999),
is 4 m long, gracile and something like _Mystriosuchus_ but with a
proportionally shorter rostrum. Strange: lower jaw seems to be longer
than upper one.The limbs appear quite slender and small; the distal
end of the very long tail is poorly ossified while fan-shaped haemal
arches and caudally bent neural spines would apparently have
stiffened the end of the tail. These features indicate that this
animal was quite aquatic.
REYNOSO, V-H. A new lizard from the Early Cretaceous lagerstatten of
Tepexi de Rodriguez, Puebla.
Mentions _Huehuecuetzpalli_, a squamate whose bizarre name was
recently commented on by Martill and Naish (1999 - in
_Geoscientist_). The new specimen regarded as a basal scincoid: can't
say more, have run out of time.
DARREN NAISH
PALAEOBIOLOGY RESEARCH GROUP
School of Earth, Environmental & Physical Sciences
UNIVERSITY OF PORTSMOUTH
Burnaby Building
Burnaby Road email: darren.naish@port.ac.uk
Portsmouth UK tel: 01703 446718
P01 3QL [COMING SOON:
http://www.naish-zoology.com]