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esembles those of Cladodoides and Tamiobatis,
especially in the proportions of its otic
region, the presence of an extensive dorsum
sellae, and the arrangement of canals for major
nerves and blood vessels. The internal
structure of the occipital region is remarkably
like that found in Tamiobatis braincases in
having a prominent subnotochordal septum
and paired subnotochordal and paroccipital
chambers. Cladodus is no longer regarded as a
nomen dubium, since only a few species
founded on isolated teeth are now retained in
the re-diagnosed genus, and one of these
(C. elegans) is now associated with skeletal
remains. The best systematic placement for
Cladodus sensu stricto is among the Ctenacanthiformes
or even the Ctenacanthidae.
Cladodus may be a synonym of Ctenacanthus,
but this cannot be confirmed with the available
material.
2008010271
Spitsbergen 早 泥 盆 世 Gigantaspis = The
genus Gigantaspis heintz, 1962 (Vertebrata,
Heterostraci) from the lower Devonian of
Spitsbergen. ( 英 文 ). Pernegre V; Goujet D.
Palaeontology, 2007, 50(2): 323-346
Material collected in 1969 by the CNRS-
MNHN expedition to Spitsbergen includes a
new species of Gigantaspis, G. minima, which
is the smallest known species of this genus.
The revision of Gigantaspis leads to the inclusion
of Zascinaspis laticephala Blieck and
Goujet in this genus. The phylogenetic analysis
presented herein suggests that Gigantaspis
is close to Zascinaspis, as suggested by Blieck.
Moreover, it is also close to generalized representatives
of the Protaspididae. Their shared
character states allow the definition of a possible
ancestral morphotype for the Protaspididae.
2008010272
得 克 萨 斯 早 白 垩 世 阿 尔 布 期 Pawpaw 页 岩
中 的 Anacoracid 类 = Anacoracid Sharks
From The Albian (Lower Cretaceous) Pawpaw
Shale of Texas. ( 英 文 ). Siverson M;
Lindgren J; Kelley L S. Palaeontology, 2007,
50(4): 939-950
Recent collecting from the Pawpaw Shale
in north-east Texas has yielded several hundred
teeth of anacoracid sharks. The material
allows for a much-needed revision of the Late
Albian anacoracids from North America. The
previously recognized Squalicorax sp., also
referred to as S. volgensis in more recent publications,
is a mix of two different species:
S. priscoserratus sp. nov. and S. pawpawensis
sp. nov. In addition to these two new species,
a single tooth is assigned to S. aff.
S. baharijensis. Our data indicate that anacoracids
were a considerably more diverse
group in the North American Cretaceous than
previously thought. We attribute much of the
underestimation of diversity to vague species
concepts, poor preparation techniques and the
associated lack of attention to certain dental
features, in particular neck morphology, root
surface porosity and the root's vascularization.
2008010273
对 存 疑 Auchenaspis 的 综 述 及 其 在
Thyestidian 演 化 上 的 作 用 = A Review Of
The Problematic Osteostracan Genus
Auchenaspis And Its Role In Thyestidian Evolution.
( 英 文 ). Sansom R. Palaeontology,
2007, 50(4): 1001-1011
The poorly understood osteostracan genus
Auchenaspis, from the Upper Silurian of England,
belongs to the thyestidians (Thyestiida),
a controversial and important group that is key
to the understanding of the evolution of the
Osteostraci and paired pectoral fins. The two
under-studied species of this genus are comprehensively
reviewed using anatomical and
novel statistical approaches. No reliable anatomical
characters can be used to distinguish
between the two species, yet discriminant
analysis finds significant separation with respect
to size. Potential causes of this conflict
are discussed. The findings enable
Auchenaspis to be considered in terms of
wider thyestidian evolution and contradict
previous interpretations of the genus as representing
a paraphyletic taxon, whose morphology
is intermediate between the general osteostracan
condition and the highly derived tremataspids.
2008010274
西 班 牙 北 部 比 利 牛 斯 山 脉 南 部 晚 坎 潘 期 及
早 马 斯 特 里 赫 特 期 ( 晚 白 垩 世 ) 的
Neoselachians = Neoselachians From The
Upper Campanian And Lower Maastrichtian
(Upper Cretaceous) Of The Southern Pyrenees,
Northern Spain. ( 英 文 ). Kriwet J; Soler-Gijón
R; López-Martínez N. Palaeontology, 2007,
50(5): 1051-1071
Bulk sampling of upper Campanian to
lower–middle Maastrichtian coastal and lagoonal
deposits in five sections of the Tremp
Formation in the south-central Pyrenees
yielded numerous neoselachian teeth. The
fauna comprises nine taxa of which three spe-
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