[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

New Journal of Vertebrate Paleontology (March 2003): New dinosaurs and more



From: Ben Creisler bh480@scn.org
New Journal of Vertebrate Paleontology (March 2003): New 
dinosaurs and more

My regular e-mail has been fried for most of the week so 
in case this item has not been mentioned here, the new 
March 2003 issue of  JVP is available on line and contains 
a number of dinosaur papers, as well as some other 
Mesozoic reptile stuff of interest.

GARCIA, G. and X. P. SUBERBIOLA, 2003. A NEW SPECIES OF 
STRUTHIOSAURUS (DINOSAURIA: ANKYLOSAURIA) FROM THE UPPER 
CRETACEOUS OF VILLEVEYRAC (SOUTHERN FRANCE). Journal of 
Vertebrate Paleontology: Vol. 23, No. 1, pp. 156-165.
 A new species of the ankylosaur Struthiosaurus  from the 
Upper Cretaceous (lower Campanian) of the Villeveyrac-Mèze 
Basin, southern France, is described from a partial 
skeleton that includes distal dorsal vertebrae, synsacrum 
and pelvic girdle. Struthiosaurus languedocensis , sp. 
nov. is a small-sized nodosaurid (less than 3 m length) 
characterised by distal dorsal centra that are very 
compressed laterally and hourglass in shape in ventral 
view; ischium directed immediately caudal from the 
acetabulum, with a robust shaft that does not taper 
distally and that is weakly curved in a caudoventral 
orientation. The synsacrum of S. languedocensis  consists 
of ten co-ossified vertebrae, including five dorsals, four 
sacrals and a caudal. Among ankylosaurs, only Polacanthus 
foxii has a similar synsacral count, but there are 
significant differences in the pelvic structure between 
Struthiosaurus  and Polacanthus . The presence of an 
ischium lacking a distinct nodosaurid-like ventral flexion 
appears to be diagnostic for the genus Struthiosaurus , as 
suggested by additional remains recovered from the upper 
Campanian of Laño (Iberian Peninsula). Current data 
suggests that Struthiosaurus  is represented by different 
species in southwestern and central Europe.

KOBAYASHI, YOSHITSUGU and YOICHI AZUMA, 2003. A NEW 
IGUANODONTIAN (DINOSAURIA: ORNITHOPODA) FROM THE LOWER 
CRETACEOUS KITADANI FORMATION OF FUKUI PREFECTURE, JAPAN.
Journal of Vertebrate Paleontology: Vol. 23, No. 1, pp. 
166-175.
 The skull material of a new iguanodontian dinosaur, 
Fukuisaurus tetoriensis gen. et sp. nov., discovered from 
the fluvial deposits of the Lower Cretaceous Kitadani 
Formation, Tetori Group, Fukui Prefecture, Japan, is 
described here. Some features of Fukuisaurus  show 
affinities with Iguanodon, Ouranosaurus, and Altirhinus, 
referred to as Iguanodontidae by some. A phylogenetic 
analysis using mainly cranial characters shows that 
Fukuisaurus  is a definitive derived non-hadrosaurid 
iguanodontian and implies that Fukuisaurus  is more 
derived than the clade of Iguanodon + Ouranosaurus  and 
more basal to the clade of Altirhinus, Probactrosaurus, 
Eolambia, Protohadros, Bactrosaurus, Telmatosaurus, and 
hadrosaurids. It also supports that Iguanodontidae is 
paraphyletic by the exclusion of Altirhinus as suggested 
previously. The presence of Fukuisaurus  indicates a wider 
geographical distribution of the group in eastern Asia. 
The occurrences of derived non-hadrosaurid iguanodontians 
from the Kitadani Formation and other formations in Japan 
support a dispersal of this group into eastern Asia by the 
Early Cretaceous and its temporal range extension in 
Japan. Fukuisaurus  possesses a strong maxilla-vomer 
articulation, indicative of the independent acquisition of 
a non-pleurokinetic skull (not present in Hypsilophodon, 
Iguanodon, and hadrosaurids).


TIDWELL, V. and K. CARPENTER, 2003. BRAINCASE OF AN EARLY 
CRETACEOUS TITANOSAURIFORM SAUROPOD FROM TEXAS. Journal of 
Vertebrate Paleontology: Vol. 23, No. 1, pp. 176-180.
The first braincase belonging to an Early Cretaceous 
sauropod from North America is described. The diagnostic 
characters of this well preserved partial braincase are: 
prominent supraoccipital crest, with a distinct median 
ridge extending almost to the foramen magnum; short, 
ventrally directed basitubera, divided by a deep groove 
extending to the basipterygoid; single foramen for cranial 
nerve XII; accessory foramen for cranial nerve XI. A lack 
of juvenile characters suggests this specimen, although 
quite small, belongs to an adult individual. Comparison of 
this specimen with other sauropod crania indicates strong 
similarities with brachiosaurids and titanosaurids.


SULLIVAN, R. M. 2003. REVISION OF THE DINOSAUR STEGOCERAS 
LAMBE (ORNITHISCHIA, PACHYCEPHALOSAURIDAE).
Journal of Vertebrate Paleontology: Vol. 23, No. 1, pp. 
181-207.
 Stegoceras (sensu lato) has been the recipient of a 
number of species. Most have been placed into synonymy 
with S. validum , some have been transferred to other 
genera (i.e., Gravitholus , Ornatotholus)  whereas others 
have been interpreted as being sexual dimorphs. A 
parsimonious phylogenetic analysis using 49 characters, 
which include 9 new cranial characters based on 
pachycephalosaur frontoparietal domes, now permits a 
revision of the genus Stegoceras.
 This analysis concludes that Stegoceras validum  (sensu 
stricto) is a primitive, incipiently-domed 
pachycephalosaur that is characterized by a well-developed 
squamosal shelf and open supratemporal fossae. It is the 
sister taxon to the fully-domed Pachycephalosaurinae. The 
taxon Ornatotholus browni  has a parietal and displays 
features identical to S. validum  and is therefore a 
subjective junior synonym. Specimens consisting of flat, 
paired frontals are immature individuals of S. validum. 
The holotype of ?Stegoceras ? lambei , and all morphotypes 
of this species, are unique in the construction of the 
posterior squamosal region and are placed in a new genus, 
Colepiocephale. Colepiocephale lambei  is known solely 
from the Foremost Formation and is the oldest diagnostic 
pachycephalosaur from North America. An incomplete, and 
indeterminate, skull from the upper part of the Milk River 
Formation (upper Santonian) has the distinction of being 
the oldest known North American pachycephalosaur.  
sternbergi  lacks a posterior squamosal shelf and has 
squamosals directed laterally and is placed in a new 
genus, Hanssuesia , as H. sternbergi . Although the taxon 
Gravitholus albertae  displays some characters (i.e., 
retention of the posterior squamosals separated by a 
distinct median parietal) and is similar to H. sternbergi  
in some respects, the holotype is too incomplete for any 
definitive diagnosis and thus it is considered a nomen 
dubium. Sphaerotholus  is a subjective junior of 
Prenocephale  and the species Sphaerotholus buchholtzae  
is a subjective junior synonym of Prenocephale 
edmontonensis . The taxa Prenocephale brevis , P. 
edmontonensis , and P. goodwini , form a monophyletic 
clade with monotypic Asian taxa Prenocephale prenes  and 
Tylocephale gilmorei  as an unresolved sister group. They 
are united by the possession of a distinct row of nodes on 
the squamosal and parietals. Tylocephale , if valid, is 
interpreted as the sister taxon to the Prenocephale clade .
 Stenotholus kohleri  is formally recognized as a junior 
synonym of Stygimoloch spinifer . Based on the presence of 
hypertrophied nodes Stygimoloch spinifier  and 
Pachycephalosaurus wyomingensis  are united in the clade 
Pachycephalosaurini new taxon.
 Small-to-medium size Late Cretaceous pachycephalosaurs 
were rather diverse, especially during the late Campanian 
(Judithian), and many species coexisted during Campanian 
and Maastrictian times. Ancestry and directionality of 
dispersal (in part) of the North American and Asian taxa 
remains uncertain and certainly antedates Campanian time.

UPCHURCH, P.  and J. MARTIN, 2003. THE ANATOMY AND 
TAXONOMY OF CETIOSAURUS  (SAURISCHIA, SAUROPODA) FROM THE 
MIDDLE JURASSIC OF ENGLAND. Journal of Vertebrate 
Paleontology: Vol. 23, No. 1, pp. 208-231.
 The Middle Jurassic sauropod Cetiosaurus is significant 
both historically and in terms of its potential 
phylogenetic relationships. The anatomy and taxonomy of 
this form are poorly understood because inadequate 
diagnoses have allowed the proliferation of species names 
and the referral of very fragmentary specimens. A review 
of Cetiosaurus species indicates that all, except C. 
oxoniensis  are unavailable or nomina dubia. The current 
type species, C. medius , can no longer be regarded as a 
valid taxon. Previous suggestions that Cardiodon  is a 
senior subjective synonym of Cetiosaurus cannot be 
sustained because the two forms do not share any 
autapomorphies. It is proposed that the generic name 
Cetiosaurus  be retained, with C. oxoniensis  as the new 
type species. The most complete specimen of C. oxoniensis  
(a partial skeleton from Bletchingdon Station, 
Oxfordshire) is redescribed and compared with other 
sauropods. Cetiosaurus  is rediagnosed on the basis of 
autapomorphies, including: (1) ?pyramid?-shaped neural 
spines in posterior cervical and anterior dorsal 
vertebrae; (2) loss of the spinodiapophyseal lamina on all 
dorsal vertebrae; (3) anterior chevrons with 
anteroposteriorly compressed distal shafts; (4) distal 
caudal centra have a ?tongue?-like projection at the 
dorsal midline of their articular ends; and (5) a distinct 
triangular hollow on the lateral surface of the ilium at 
the base of the pubic process.

SATO, T. 2003. TERMINONATATOR PONTEIXENSIS , A NEW 
ELASMOSAUR (REPTILIA; SAUROPTERYGIA) FROM THE UPPER 
CRETACEOUS OF SASKATCHEWAN. Journal of Vertebrate 
Paleontology: Vol. 23, No. 1, pp. 89-103.
 A new elasmosaur, Terminonatator ponteixensis , gen. et 
sp. nov., from the Upper Campanian Bearpaw Formation of 
southwestern Saskatchewan, Canada, is one of the youngest 
plesiosaurs from the Western Interior, and one of the few 
plesiosaurs for which detailed osteology of both skull and 
postcrania is available. The skull includes the upper side 
of the inner ear cavity and a median portion of the roof 
of the braincase. This taxon is distinguished from other 
elasmosaurs by a combination of several osteological 
characters variable among elasmosaurs, as well as the 
unique feature of a high and pointed coronoid process. 
Anomalous ossification is seen in the fused or pronged 
gastralia, development of tubercules in metacarpals, and 
healed fracture of the limb. The dorsal portion of the 
braincase is compared with other plesiosaurs, showing a 
variation in plesiosaur braincase morphology. Identity of 
carpal and tarsal elements is examined based on recent 
debates on the homology of mesopodials.


GASPARINI, Z.,  N. BARDET, J. E. MARTIN, and M. FERNANDEZ, 
2003. THE ELASMOSAURID PLESIOSAUR ARISTONECTES CABRERA 
FROM THE LATEST CRETACEOUS OF SOUTH AMERICA AND 
ANTARCTICA. Journal of Vertebrate Paleontology: Vol. 23, 
No. 1, pp. 104-115.
ABSTRACT
 Aristonectes parvidens , and Morturneria seymourensis  
(Chatterjee and Small, 1989 ), two plesiosaurs from the 
Maastrichtian of South America and Antarctica whose 
phylogenetical position is controversial, are reviewed and 
found to be congeneric and conspecific. Most differences 
between the two type specimens are interpreted as related 
to ontogenetic growth: Morturneria  is based on an 
immature, whereas Aristonectes  is based on an adult, 
probably an old individual. Aristonectes  exhibits an 
unique set of characters among Plesiosauria: a low and 
wide ogival skull, a paired vomero-nasal fenestra, a 
mandible high anteriorly with a very short and high 
symphysis, a homodont dentition composed of numerous, 
strongly outwardly directed and poorly ornamented teeth 
(dental formula: 10-13 premaxillary, at least 51 maxillary 
and probably 60-65 dentary teeth, depending upon 
individual ontogeny). Moreover, Aristonectes  shares 
several synapomorphies with the elasmosaurid clade, mainly 
strongly binocular-shaped and platycoelous cervical centra 
with lateral ridges. In contrast to cryptoclidids, it 
retains some plesiomorphic characters (e.g., horizontal 
jugal and poorly ventrally excavated cheek, glenoid fossa 
at about the same level as the alveolar row). The dental 
morphology and peculiar occlusal pattern, forming an 
interlocking trap, suggest that Aristonectes  strained a 
diet of small, soft organisms from the water.

MAISCH, M. W. and A. T. MATZKE, 2003. THE CRANIAL 
OSTEOLOGY OF THE ICHTHYOSAUR LEPTONECTES CF. TENUIROSTRIS 
FROM THE LOWER JURASSIC OF ENGLAND. Journal of Vertebrate 
Paleontology: Vol. 23, No. 1, pp. 116-127.
 For the first time, a three-dimensionally preserved skull 
of the Lower Jurassic leptonectid ichthyosaur Leptonectes  
is described. The specimen reveals a wealth of new data on 
the cranial anatomy of basal leptonectid neoichthyosaurs. 
The osteology of the skull roof differs fundamentally from 
other well-known post-Triassic ichthyosaurs and is highly 
autapomorphic. The structure of the sclerotic ring, which 
is well preserved in situ, is described and it appears 
plausible that cf. tenuirostris  was capable of 
stereoscopic vision. Inadequate description makes 
comparison to other leptonectids difficult. It can be 
demonstrated, however, that cf. tenuirostris  is most 
similar to L. tenuirostris among known leptonectids. It is 
fundamentally different from the Upper Liassic 
Eurhinosaurus longirostris  in the osteology of the skull 
roof and the size and orientation of the major skull 
openings, making generic distinction of these two species 
a necessity. At the moment, no autapomorphies are known of 
the genus Leptonectes  which therefore must be considered 
as a metataxon that comprises basal leptonectids from the 
Lower to Middle Liassic.


ROGERS, J. V. 2003. PACHYCHEILOSUCHUS TRINQUEI , A NEW 
PROCOELOUS CROCODYLIFORM FROM THE LOWER CRETACEOUS 
(ALBIAN) GLEN ROSE FORMATION OF TEXAS. Journal of 
Vertebrate Paleontology: Vol. 23, No. 1, pp. 128-145.
 A new mesoeucrocodylian, Pachycheilosuchus trinquei , 
from the Lower Cretaceous (Albian) Glen Rose Formation, 
exhibits progressive caudal-to-cranial vertebral procoely. 
This modification is characterized by an intermediate semi-
procoelous condition in which the posterior condyle is 
dimpled by a concavity. Pachycheilosuchus  differs from 
all known crocodyliforms in having an expanded maxillary 
margin that displaces the tooth row medially, and in 
possessing a cervical shield formed by the complete fusion 
of six osteoderms. Phylogenetic analysis indicates a 
sister taxon relationship with the weakly defined 
Atoposauridae. The presence of variable procoely in both 
Pachycheilosuchus  and the closely related atoposaurid 
Theriosuchus  indicates convergent evolution of the 
character with Eusuchia. Sediments at the locality were 
deposited in near-shore, marine-to-brackish waters, 
suggesting that Pachycheilosuchus  inhabited euryhaline 
marine environments.