[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Asylosaurus and friends (now published).
More direct links to the papers:
----- Original Message -----
From: "Denver Fowler" <firstname.lastname@example.org>
Sent: Monday, March 17, 2008 3:21 AM
Subject: Re: Asylosaurus and friends (now published).
I'll note that the paper is freely available here:
----- Original Message ----
From: Tim Williams <email@example.com>
To: firstname.lastname@example.org; email@example.com
Sent: Sunday, 16 March, 2008 7:56:50 PM
Subject: Asylosaurus and friends (now published).
This is a HUGE paper - so big that the journal (Revue de Paléobiologie)
split it into two files.
Galton, Peter M. (2007). Notes on the remains of archosaurian reptiles,
mostly basal sauropodomorph dinosaurs, from the 1834 fissure fill
(Rhaetian, Upper Triassic) at Clifton in Bristol, southwest England.
Revue de Paléobiologie, Genève 26 (2): 505-591.
Abstract: "Many of the best preserved teeth and bones of archosaurian
reptiles found in 1834 in an Upper Triassic Rhaetian fissure fill on
Down in Clifton (now in Bristol), southwest England were destroyed in
1940. Based on an 1875 map, the site is positively identified
as within Quarry Steps Quarry. This paper includes an annotated
catalogue, copies of most of the illustrations from 1840 to 1908, and
photos of important extant specimens. Most of the recognizable, mostly
unassociated and incomplete bones have long been referred
to the basal sauropodomorph dinosaur _Thecodontosaurus_ Riley &
Stutchbury, 1836 (as _T. antiquus_ Morris, 1843), with gracile
and robust morphs of several of the appendicular bones as a sexual
dimorphism. The deltopectoral crest of unassociated Clifton
humeri is plesiomorphic for basal sauropodomorphs, being anteroposteriorly
high and markedly asymmetrical in lateral view with a
short edge distal to the very prominent apex. The apex is at 40%
(measured perpendicular to long axis of humerus) of total length in
gracile ones and +50% in robust ones of the same size. However, the
former position is plesiomorphic for sauropodomorphs, the latter
derived, and no other basal sauropodomorph species h
rom Clifton, which
includes a forelimb and girdle, has a third humeral morph with a low
symmetrical deltopectoral crest with a rounded apex at 25% of
length. Whatever the status of the gracile and robust morphs, the
characters of referred postcranial bones from Clifton cannot be used
to distinguish the species of _Thecodontosaurus_ Riley & Stutchbury, 1836
that, along with _T. antiquus_ Riley & Stutchbury vide
Owen, 1842, may be a nomen dubium. However, _T. antiquus_ is retained for
the slender humeral morph pending the description of
referred material from a Rhaetian fissure fill at Tytherington Quarry,
Avon. In the humerus of _Pantydraco_ (_Thecodontosaurus_) _caducus_
(Upper Triassic/Lower Jurassic, Wales) the apex of the asymmetrical
deltopectoral crest is at 40% of the length and the process is
low, a morph that is not represented at Clifton. The Clifton forelimb and
girdle is made the holotype of _Asylosaurus yalensis_ n. gen.
et sp. The manus shows lateral reduction, so phalangeal formula is
2-3-4-2-?1, and the humerus has a large medial tubercle (small
in Welsh humerus). The other Clifton bones are identified as either: A.
very basal Sauropodomorpha indet (could be _Asylosaurus_ or
_Thecodontosaurus_, includes slender morph bones); B. Anchisauria indet
(more derived than A, includes robust morph bones); or C.
basal Sauropodomorpha indet (could be A or B).
"An ilium and two femora are very basal Theropoda (or possibly
Dinosauriformes); other theropod remains include a small tooth
crown with fine perpendicular denticles, a metacarpal I, a slender
recurved manual ungual, and an astragalus. A dorsal centrum may
be from an ornithischian dinosaur. _Rileyasuchus_ Kuhn, 1961 (type
species _Palaeosaurus platyodon_ Riley & Stutchbury, 1840), a
nomen dubium, is a heterodont crurotarsal phytosaur now represented by two
teeth and two humeri. The denticles are angled slightly
apically on the expanded mesial blade and perpendicular to the distal
edge. _Palaeosauriscus_ Kuhn, 1959 (type species _Palaeosaurus
Stutchbury, 1840) is based on lost teeth; it is Archosauria indet but may
be a valid taxon based on the
subcircular cross-section and fine, obliquely inclined denticles. A few
bones are none of the above and are Archosauria indet (dentary
with teeth, scapula-coracoid) and even Reptilia indet (?prootic, parietal,
distal femur, tibia, metapodial)."
_Thecodontosaurus antiquus_ looks like it might be safe as a valid taxon,
based on as-yet-published work. Says Galton: "_T. antiquus_ ... is
provisionally accepted as a valid taxon, the complete diagnosis of which
awaits description of the referred bones from Tytherington Quarry by Yates
& Benton (in prep.)."
The new guy is _Asylosaurus yalensis_ (info taken directly from Galton
Etymology: Greek asylos = unharmed, safe from violence or asylon = refuge,
sanctuary + sauros = lizard; yalensis = of Yale College (now University),
where O. C. Marsh took specimen so it was unharmed in air raids on BCM in
Distribution: Upper Triassic (Rhaetian) of England.
Holotype: YPM 2195, an associated partial skeleton consisting of dorsal
vertebrae, ribs and gastralia, pectoral girdle, right and proximal left
humeri, articulated left forearm (radius very incomplete) and manus; also
YPM 2195a-g, disarticulated bones on block tentatively referred to
holotype individual (or species for femora), viz., vertebrae (cervical ~4
or 5, caudals ~10 and ~15), proximal medial part of right ulna, distal
left ischium, 2 distal femora: larger right and smaller left, distal right
Hypodigm: proximal left humerus (BMNH R1542), manual phalanx 1 of digit I
(YPM 56745), ischia (YPM 56725, 56726, 56739).
And, as the abstract says, _Palaeosauriscus_ might be a valid taxon -
although it's not clear what it actually is.
Shed those extra pounds with MSN and The Biggest Loser!
Rise to the challe
J'utilise la version gratuíte de SPAMfighter pour utilisateurs privés.
Ce programme a supprimé3962 d'e-mails spam à ce jour.
Les utilisateurs qui paient n'ont pas ce message dans leurse-mails.
Obtenez la version gratuite de SPAMfighter ici: http://www.spamfighter.com/lfr