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Oolon Colluphid · 02-22-2002, 03:16 AM

Last night BBC2 screened an episode of the (often hyperbolic, but otherwise estimable) Horizon (which I think gets called Nova in the US), on the Archaeoraptor affair. (I keep thinking that Archaeoraptor shoud be the name of something that steals old movies*

) I haven’t watched it back yet, but the good old Beeb has details <a href="http://www.bbc.co.uk/science/horizon/2001/dinofool.shtml" target="_blank">here</a>, and a full programme transcript <a href="http://www.bbc.co.uk/science/horizon/2001/dinofooltrans.shtml" target="_blank">here</a>.

Quote:

The new Archaeoraptor fossil, also from the Liaoning region of China, seemed to be just that [a transitional]. Here, in one animal, was a unique range of dinosaur and bird features. It had the skull and upper body of a bird, but the teeth and hands of a dinosaur. It also had the legs of a bird but the tail of a dinosaur. It was the most complete set of transitional features ever found in one creature. In November 1999 National Geographic Magazine gave it a special mention in an article about the origins of birds, calling it, "a true missing link.". The debate, started by Thomas Huxley in the 1860s, seemed to have been resolved.

Yet within months, new finds in China showed Archaeoraptor to be an extremely clever fake. The head and upper body of a hitherto unidentified bird had been glued onto the tail of a previously unknown dinosaur. It was a journalistic disaster for National Geographic Magazine. The fossil, however, was anything but a disaster for palaeontology. By an extraordinary stroke of good luck, as scientists in China and America examined the head and tail separately, they found that both were, in their own right, unique and extremely valuable specimens. Both, in their different ways, contained powerful evidence that birds had evolved from dinosaurs. [My emphasis]

* RKO raptor. Oh never mind.

Cheers, Oolon

[ February 22, 2002: Message edited by: Oolon Colluphid ]</p>

ps418 · 02-24-2002, 08:29 AM

Exactly. Part of Archaeoraptor is now known as Microraptor, which is the smallest known non-avian dinosaur and is also extremely bird-like -- compare Microraptor to Rahonavis, for instance.

To repost from my bird-like dinos thread:

Microraptor zhaoianus. Xu et al., 2000. Nature 408, pp. 705-708.

Abstract:

Non-avian dinosaurs are mostly medium to large-sized animals, and to date all known mature specimens are larger than the most primitive bird, Archaeopteryx. Here we report on a new dromaeosaurid dinosaur, Microraptor zhaoianus gen. et sp. nov., from the Early Cretaceous Jiufotang Formation of Liaoning, China. This is the first mature non-avian dinosaur to be found that is smaller than Archaeopteryx, and it eliminates the size disparity between the earliest birds and their closest non-avian theropod relatives. The more bird-like teeth, the Rahonavis -like ischium and the small number of caudal vertebrae of Microraptor are unique among dromaeosaurids and improve our understanding of the morphological transition to birds. The nearly completely articulated foot shows features, such as distally positioned digit I, slender and recurved pedal claws, and elongated penultimate phalanges, that are comparable to those of arboreal birds. The discovery of these in non-avian theropods provides new insights for studying the palaeoecology of some bird-like theropod dinosaurs.

Xu et al. write:

"The discovery of Microraptor completes some morphological gaps between dromaeosaurid dinosaurs and birds; for example, it has more bird-like teeth than do other dromaeosaurids, a Rahonavis-like ischium, enlarged sacrals and fewer caudal vertebrae" (p. 707).

Other characters: extremely small- trunk length estimated 47mm; tail consisting of 24-25 caudal vert., possessing rod-like extensions of prezygapophyses and chevrons, as in other dromaeosaurs; gastralia; semilunate carpal; Metatarsals II, III, and IV unfused and of unequal length as in other dromaeosaurs, Archaeop., and other early birds, versus fused MTs of equal length in later birds. MT IV bears pronounced flange on posteromedial surface, as in other dromaeosaurs; second pedal digit is specialized raptorial tool as in dromaeosaurs, troodonts, Archaeop., and Rahonavis; Pedal digit I distally placed, but not retroverted, as in Archaeop. and other early birds. Also, large patches of integumentary covering:

"Large patches of integuments are preserved in situ around the skeleton, and the pattern of preservation is similar to that of early birds from the same locality. Integumentary structures are best preserved near the femur, where they run almost perpendicular to the bone. They are long (average 25-30mm), narrow, and have a feather-like contour, whereas those along the tibia and in the hip area are shorter. Some impressions of the integuments contain a structure similar to that of a rachis, suggesting that true feathers may have been present. . . " (p. 707).

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02-24-2002, 08:29 AM	#2
ps418 Veteran Member Join Date: Mar 2001 Location: Louisville, KY, USA Posts: 1,840	Exactly. Part of Archaeoraptor is now known as Microraptor, which is the smallest known non-avian dinosaur and is also extremely bird-like -- compare Microraptor to Rahonavis, for instance. To repost from my bird-like dinos thread: Microraptor zhaoianus. Xu et al., 2000. Nature 408, pp. 705-708. Abstract: Non-avian dinosaurs are mostly medium to large-sized animals, and to date all known mature specimens are larger than the most primitive bird, Archaeopteryx. Here we report on a new dromaeosaurid dinosaur, Microraptor zhaoianus gen. et sp. nov., from the Early Cretaceous Jiufotang Formation of Liaoning, China. This is the first mature non-avian dinosaur to be found that is smaller than Archaeopteryx, and it eliminates the size disparity between the earliest birds and their closest non-avian theropod relatives. The more bird-like teeth, the Rahonavis -like ischium and the small number of caudal vertebrae of Microraptor are unique among dromaeosaurids and improve our understanding of the morphological transition to birds. The nearly completely articulated foot shows features, such as distally positioned digit I, slender and recurved pedal claws, and elongated penultimate phalanges, that are comparable to those of arboreal birds. The discovery of these in non-avian theropods provides new insights for studying the palaeoecology of some bird-like theropod dinosaurs. Xu et al. write: "The discovery of Microraptor completes some morphological gaps between dromaeosaurid dinosaurs and birds; for example, it has more bird-like teeth than do other dromaeosaurids, a Rahonavis-like ischium, enlarged sacrals and fewer caudal vertebrae" (p. 707). Other characters: extremely small- trunk length estimated 47mm; tail consisting of 24-25 caudal vert., possessing rod-like extensions of prezygapophyses and chevrons, as in other dromaeosaurs; gastralia; semilunate carpal; Metatarsals II, III, and IV unfused and of unequal length as in other dromaeosaurs, Archaeop., and other early birds, versus fused MTs of equal length in later birds. MT IV bears pronounced flange on posteromedial surface, as in other dromaeosaurs; second pedal digit is specialized raptorial tool as in dromaeosaurs, troodonts, Archaeop., and Rahonavis; Pedal digit I distally placed, but not retroverted, as in Archaeop. and other early birds. Also, large patches of integumentary covering: "Large patches of integuments are preserved in situ around the skeleton, and the pattern of preservation is similar to that of early birds from the same locality. Integumentary structures are best preserved near the femur, where they run almost perpendicular to the bone. They are long (average 25-30mm), narrow, and have a feather-like contour, whereas those along the tibia and in the hip area are shorter. Some impressions of the integuments contain a structure similar to that of a rachis, suggesting that true feathers may have been present. . . " (p. 707).

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