[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
RE: _Hadrosaurus_ in new Acta Palaeontologica Polonica
Christopher Taylor wrote:
Albert Prieto-Márquez, David B. Weishampel, and John R. Horner. 2006.
The dinosaur Hadrosaurus foulkii, from the Campanian of the East Coast
of North America, with a reevaluation of the genus. Acta Palaeontologica
Polonica 51 (1): 77-98.
The authors ditch _Hadrosaurus foulkii_ as a valid species, but retain
Hadrosauridae as a valid family.
There's also this (loosely dino-related):
Jørn H. Hurum, Zhe-Xi Luo, and Zofia Kielan-Jaworowska (2006). Were mammals
originally venomous? Acta Palaeontologica Polonica 51 (1): 1-11
Abstract: "The extratarsal spur in extant monotremes consists of an os
calcaris and a cornu calcaris. A poisonous extratarsal spur occurs only in
the platypus (_Ornithorhynchus_); a possibly secondarily non-poisonous spur
is present in echidnas (_Tachyglossus_ and _Zaglossus_). Some therian
mammals (e.g., bats), reptiles (_Chamaeleo_), and amphibians have a
spur-like structure in the ankle, but this is not homologous to the
extratarsal spur of monotremes. Among fossil mammals, the co-ossified os
calcaris and ossified cornu calcaris have been found in the eutriconodontan
_Gobiconodon_ and in the spalacotheroid ?symmetrodontan? _Zhangheotherium_.
Here we describe the os calcaris in several multituberculate mammals from
the Late Cretaceous of the Gobi Desert, Mongolia. The multituberculate os
calcaris is a large, flat bone, generally similar to that in males of the
extant monotreme species, but the cornu calcaris is not ossified. In
_Gobiconodon_ and _Zhangheotherium_ the ossified cornu calcaris is fused to
the os calcaris probably to provide the bony support for the keratinous
spur. We hypothesize that the os calcaris in these Mesozoic mammal groups
is homologous to that of monotremes. However, the extratarsal spur has not
been found in non-mammalian cynodonts nor in other synapsids. A
platypus-like os calcaris might be an apomorphic characteristic of basal
Mesozoic mammals and is secondarily lost in crown therians; the os calcaris
is confirmed to be absent in well-preserved tarsal structures of the
earliest known crown therian mammals. We speculate that the os calcaris,
the cornu calcaris, and its associated venom gland might have served the
function of a defensive structure during the ?dark ages? of mammalian
history, when dinosaurs ruled the Earth. This structure is a plesiomorphic
character retained in extant monotremes and cannot be used as an
autapomorphy of Monotremata."