[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Also new in Historical Biology
Yates, A.M. (2006). Solving a dinosaurian puzzle: the identity of _Aliwalia
rex_ Galton. Historical Biology, iFirst article, 1-30.
Abstract: "_Eucnemesaurus fortis_ Van Hoepen 1920 from the Late Triassic of
South Africa is demonstrated to be the senior synonym of the puzzling
dinosaur taxon _Aliwalia rex_ Galton 1985. A new specimen of this
poorly-known taxon is described. _Eucnemesaurus_ is clearly a sauropodomorph
and increases the diversity of sauropodomorph taxa in the South African Late
Triassic to six. It shares a number of femoral synapomorphies with
_Riojasaurus_ from the Late Triassic of Argentina and Riojasauridae tax.
nov. is erected to accommodate them. These conclusions are supported by a
comprehensive cladistic analysis of 46 sauropodomorph and other basal
dinosauriformtaxa using 353 osteological characters. This analysis also
supports the paraphyletic nature of the traditional ?prosauropod?
Also erects the new taxon Massopoda (defined as _Saltasaurus_ but not
_Plateosaurus_), and re-defines Sauropoda (_Saltasaurus_ but not
_Melanorosaurus_). Thus Sauropoda is a subset of Massopoda.
_Plateosauravus_ and _Eucnemesaurus_ are both valid taxa (mentioned before).
The analysis shows _Ruehleia_ as the sister taxon to the
Massopoda+Plateosauridae clade. I guess this clade would be Plateosauria -
Yates uses it as such, following Sereno (1998). But Plateosauria was
defined under the assumption that _Plateosaurus_ and _Massospondylus_ formed
a clade to the exclusion of eusauropods, which no longer holds; so Sereno
(2005) re-defined Plateosauria such that _Saltasaurus_ is a negative
Bonaparte, J.F, Brea, G., Schultz, C.L., and Martinelli, A.G. (2006). A new
specimen of _Guaibasaurus candelariensis_ (basal Saurischia) from the Late
Triassic Caturrita Formation of southern Brazil. Historical Biology, iFirst
Abstract: ?The comparison of the anatomy of a second incomplete skeleton of
_Guaibasaurus candelariensis_ to that of basal Saurischia suggests that the
origin of the ?Prosauropoda? was from unknown basal saurischians, after
separating from theropods (except herrerasaurids). _Guaibasaurus_ and
_Saturnalia_ are part of this early dichotomy, and they bear mixed
characters-states of basal theropods and ?prosauropods? type. The Late
Triassic age of both _Guaibasaurus_ and _Saturnalia_(the latter is older)
predates the ?dominance? of basal sauropodomorphs as well as the appearance
of the basal theropod _Zupaysaurus_, both recorded from the upper Los
Colorados Formation of Argentina.?
Ferigolo, J. and Langer, M.C. (2006). A Late Triassic dinosauriform from
south Brazil and the origin
of the ornithischian predentary bone. Historical Biology, iFirst article,
Abstract: ?The South American Late Triassic offers the most comprehensive
window to the early radiation of dinosaurs. This is enhanced by the
discovery of _Sacisaurus agudoensis_, a new dinosauriform from the Caturrita
Formation of Brazil. Various morphological features suggest its close
phylogenetic affinity to _Silesaurus_, and both may be basal ornithischian
dinosaurs. __Sacisaurus_ has a pair of elements forming the tip of its lower
jaw, hypothesized to be equivalent to the ornithischian predentary. This
suggests that during an initial stage of their evolution, those dinosaurs
had a paired predentary, which later fused into a single structure. As an
originally paired bone, the predentary is comparable to elements that more
often form the vertebrate mandible, such as the mentomeckelian bone.
Although synapomorphic for ornithischians, the predentary does not seem
neomorphic for the group, but primarily homologous to parts of the
symphyseal region of the lower jaw of other vertebrates.?
Ezcurra, M. (2006). The cranial anatomy of the coelophysoid theropod
_Zupaysaurus rougieri_ from the Upper Triassic of Argentina. Historical
Biology, iFirst article, 1-18.
Abstract: ?_Zupaysaurus rougieri_ is a theropod dinosaur that is known from
an almost complete skull and limited postcranial material (e.g., axial
elements, scapulocoracoid, tibia, astragalocalcaneum), from the Los
Colorados Formation (La Esquina Fauna, Norian), NW Argentina. This taxon was
originally interpreted as a basal tetanuran, but is actually a member of the
Coelophysoidea. _Zupaysaurus_ differs from other basal dinosaurs in the
presence of the following cranial apomorphies: a maxillary-jugal ventral
margin describing an obtuse angle in lateral view, a horizontal ramus of the
maxilla with parallel dorsal and ventral margins, a notch at the base of the
ascending process of the maxilla, and a sigmoid ventral process of the
squamosal. Furthermore, the skull of this theropod reveals anatomical
novelties (e.g., pneumatic lacrimal, maxillary fenestra, oval orbit, wide
contact between squamosal and quadratojugal) absent in any other Triassic
dinosaur hitherto described, including remaining coelophysoids.
Interestingly, these features resemble morphological aspects of more derived
theropods, approaching some traits of tetanuran and ceratosaurian
neotheropods. In this regard, a redescription of the skull of _Zupaysaurus_
and comparisons with basal neotheropods, mainly coelophysoids, is presented
here in order to provide a better cranial anatomical record for this
Triassic theropod and insights to their early cranial evolution.?
Ezcurra, M.D. and Novas, F.E. (2006). Phylogenetic relationships of the
Triassic theropod _Zupaysaurus rougieri_ from NW Argentina. Historical
Biology, iFirst article, 1-18.
Abstract: ?The anatomy and phylogenetic relationships of the Upper Triassic
theropod _Zupaysaurus rougieri_ are reviewed. This taxon is represented by a
nearly complete skull and fragmentary postcranial remains recovered from the
Los Colorados Formation (Norian), NW Argentina. Originally, _Zupaysaurus
rougieri_ was considered a basal member of the Tetanurae, but its anatomy
closely resembles that of the Coelophysoidea, supporting its nesting within
this theropodan subclade. Thus reinterpreted, _Zupaysaurus_ represents the
first record of coelophysoids in South America. Phylogenetic analyses
perfomed in this study depict _Zupaysaurus_ as a non-coelophysis
[sic]coelophysoid. Autopomorphic traits of _Zupaysaurus_ include:
maxillary-jugal ventral margin forming an obtuse angle in lateral view,
tibia with a very deep and caudally open caudal fossa for the reception of
an astragalar caudal process. Within the phylogenetic context outlined here,
the derived features shared with Tetanurae (e.g. maxillary fenestra,
caudally forked ascending ramus of the maxilla) are better interpreted as
homoplasies rather than tetanuran derived features.?
And the one already mentioned?
Irmis, R.B., Parker, W.G, Nesbitt, S.J., Liu, J. (2006). Early ornithischian
dinosaurs: the Triassic record.
The holotype of _Technosaurus_ is restricted to the premaxilla and dentary.
The premaxilla (at least) very closely resembles that of _Silesaurus_.
The posterior mandibular fragment is referred to _Shuvosaurus_
_Azendohsaurus_ - probably non-dinosaurian, and related to a Madagasan taxon
originally (and erroneously, based on more material) described as a
prosauropod (Flynn et al., 1999).
_Galtonia_ and _Pekinosaurus_ - referred to _Revueltosaurus_ as
_Tecovasaurus_, _Lucianosaurus_, _Crosbysaurus_ and _Protecovasaurus_ - all
valid taxa, but cannot be classified as anything other than Archosauriformes
All-in-one security and maintenance for your PC. Get a free 90-day trial!