Gauthier Essay Research Paper As promised here free essay sample

Gauthier Essay, Research Paper As promised, here are the derived characters with which Gauthier ( in his 1986 paper ) unites Archaeopteryx with modern birds, outside of all other bird-footed dinosaurs ( with Gauthier # 8217 ; s original clarifiers in parens ) [ and with my column remarks in brackets ] : Premaxillae elongate, narrow, and more pointed anteriorly, with longer nasal processes [ similar status in bullatosaurs, and in the nondinosaurian Megalancosaurus, but alone to Archie and subsequently birds in Maniraptora ] . Maxillary procedure of premaxilla reduced so that upper jaw participates loosely in external naris ( besides in troodontids ) . Enlarged brain/basicranium ( temporal muscular structure fails to widen beginning onto frontal castanetss [ to a certain grade in bullatosaurs and therizinosauroids, and possibly in some of the newer, brainier dromaeosaurids ] . Double-condyled quadrate displaced from distal place on opisthotic to more anteromedial place in contact with prootic ( Currie, pers. comm. and Walker, pers. comm. , disagree with Whetstone # 8217 ; s reading of the quadrate: Currie notes the anterior supplanting of the quadrate in troodontids [ possibly Nino can notice on the status in Pelecanimimus ] , and Walker does non see the quadrate to be double-condyled in Archaeopteryx ) . Maxillary and dentary dentitions reduced in size and figure ( or lost ) , with unserrated Crowns and enlarged roots that wholly enclose replacing dentitions within them [ many of the smallest bird-footed dinosaur dentitions are unserrated, which may be a developmental restraint. The adenoidal roots of bird dentitions are similar to those of troodontids, basal ornithomimosaurs, and ( in at least a twosome of instances ) dromaeosaurids ] . Robust furcula for enlarged flight muscular structure [ true to a certain extent, although oviraptorids and ( possibly ) some dromaeosaurids have significant furculae every bit good, and even the new Morrison? allosaurid seems to hold a crude furcula! ] . Scapula with more or less outstanding acromial process procedure for ligamentous connexion to collarbone. Lenght/bredth ratio of shoulder blade at midlength exceeds nine ( non in penguins ) and scapula tapers distally. Acrocoracoid tubercle larger than in other coelurosaurs. Coracoid enlaged and inflected posteromedially more so than in other coelurosaurs. Very long forelimb and custodies ( e.g. , in Archaeopteryx forelimb is 120-140 % of hind limb length, and more than twice every bit long as distance between glenoid and cotyloid cavity ) , with forearm more than 87 % of humerus length and mcII approaching or transcending one-half of humerus length. Ischium compressed and dorsoventrally deep. Compared to other bird-footed dinosaurs, shinbone, calf bone, and metatarsals comparatively more linear with regard to femur, irrespective of organic structure size ( mts abruptly in penguins and some other birds ) [ Actually, as S. Gatsey and I have shown elsewhere, what really is go oning is a difference in the allometry of bird V nonavian bird-footed dinosaur hind limb. In nonavian bird-footed dinosaurs, the tibia/fibula and the metatarsus become comparatively smaller as organic structure size ( and femur size ) increases ; in birds, the tibia/fibula and the metarsus become comparatively longer as organic structure size ( and femur size ) increases. Unfortunately, Archaeopteryx lies really near to the points at which the bird and nonbird allometric lines cross, so it is non possible to state at nowadays to which of these curves the Urvogel belongs ] . Fibula attenuate distally, and may non widen to stop of shinbone. Proximal tarsals fused to tibia/fibula and to one another in grownups [ besides in some ceratosaurs ] . Distal tarsals and metatarsals fused at least distally in to the full big persons ( convergent in some ceratosaurs, elmisaurids, and Hulsanpes ) [ future work may demo why this is no surprise for Hulsanpes ; besides found in Avimimus ] . First pedal figure elongate and reversed ( may be reversed in some extant birds ) [ the first reversed he uses is reverted ; the second is reversed in the evolutinary sense ] . Metatarsal I attached on the distal one-fourth of metatarsal II. Tail reduced to no more than 23 free caudal vertebrae. Feathers cover limbs and tail, plumes on sidelong border of tail and posterior border of weaponries enlarged, curved, and unsymmetrically vaned, bespeaking aerodynamic map [ While it is true these characteristics are presently merely known in Archaeopteryx and subsequently birds, there is merely negative grounds with respects to this character in other bird-footed dinosaurs, as discussed in the paragraph instantly following his character list ] . Therefore, there are derived characteristics associating Archaeopteryx to modern birds. In order to distort this hypothesis, extra analyses must be conducted which: a ) add new characters, or show that the above are non coded decently ; and B ) add new taxa, or show that the taxa antecedently used were non coded decently. Abundant new finds of Mesozoic birds and new bird-like bird-footed dinosaurs will assist on both these counts. With several squads working on merely this job ( gratefully non me: nonavian bird-footed dinosaurs are a job plenty! ) , we should acquire some interesting consequences. Dinosaurian Synapomorphies Found In Archaeopteryx # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; From: Dinogeorge @ aol.com Here are 20 to acquire you started ( characters shared with/retained from dromaeosaurids and other related bird-footed dinosaurs and dinosaurs ) : 1.Tridactyl hand with manual figures IV, V lost 2.Manual figure I robust 3.Manual digit II longest in manus 4.Manual figure III slender, with phalanges 3, 4 both short 5.Semilunate carpal 6.V-shaped furcula present 7.Straplike shoulder blade 8.Functionally tridactyl foots with retroverted big toe 9.Advanced mesotarsal ankle 10.Splintlike metatarsal V 11.Ascending procedure on astragalus 12.Slender calf bone 13.Femur with orthogonally inturned caput 14.Perforate cotyloid cavity 15.Pelvis reasonably opisthopubic 16.Pubis long, rodlike with distal enlargement 17.Bladelike Troy 18.Sacrum with at least 5 vertebrae ( A. has six ) 19.Long tail, distally stiffened 20.Jaws with dentitions There are tonss more # 8211 ; I # 8217 ; ve barely touched the skull in this list. But you get the thought, yes? Dromaeosaurid Archaeopteryx Gregory S. Paul # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; Geting ready for the Soc Avian Paleo A ; Evol conference on Mesozoic birds in June in DC has caused me to restudy Archaeopteryx and protoavian ( sensu Paul 1988 PDW ) bird-footed dinosaurs. With all the specimens old and new now available, virtually the full skull and skeleton is now known for Archaeopteryx. Decisions are as follows. Archaeopteryx truly is a winging bird-footed dinosaur that shows virtually no avian characters non observed in other bird-footed dinosaurs ( the big, distal, to the full reversed big toe may be the lone exclusion ) . Contrary to studies otherwise, there is no grounds for avian skull dynamicss, and the postorbital saloon was likely complete. The roof of the mouth and cranium are wholly theropodian in construction. Archaeopteryx is non merely a bird-footed dinosaur, it is a dromaeosaur because it portions a figure of elaborate characters merely with dromaeosaurs. Some other characters are found merely in the two signifiers and some basal birds. Some of the Archaeopteryx-dromaeosaur characters are as follows. oNasal depressed rhinal and neb overturned oDorsal procedure of upper jaw about reaches preorbital saloon oPreorbital saloon slender A ; consecutive preorbital in sidelong position oDorsal depression on the ectopterygoid oDiamond shaped supraoccipital oStrongly distorted paraoccipital procedure ( noted by Currie ) oHighly modified tail with hyperdorso-flexible base ( status approached in troodonts ) oMiddle finger most robust oIlium parallelogram shaped ( besides basal birds ) oPubic peduncle really big A ; reversed oIlio-pubic articulation inverted V form oPubic shafts are level home bases oriented 140 grades to each other In add-on, the pes of Archaeopteryx is functionally two toed, with a short toe II that is hyperextendable. Many Cretaceous bird-footed dinosaurs # 8211 ; dromaeosaurs, troodonts, oviraptors # 8211 ; are more bird-like than Archaeopteryx in many respects, and have a shoulder girdle that is similar to secondarily flightless birds. All this suggests that avian flight foremost evolved in arborical bird-footed dinosaurs ( where they developed large encephalons and frontward confronting eyes, characteristics non found in winging insects and flying reptiles ) , and that some of the winging bird-footed dinosaurs lost flight. Not cognizable at this clip is whether Archaeopteryx was a member of the true bird clade, or was an independent experiment in flight, or where bird-footed dinosaurs end and birds begin, among other affairs. # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; Copyright? 1996 several writers. This papers was a public station to the Dinosaur Mailing List. Feathered non-avian bird-footed dinosaurs found Jeff Punting # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; Scientists reported in the June 25, 1998, edition of the journal Nature the find of two new dodos from Liaoning, China. The early Cretaceous Liaoning site is already known for its spectacularly preserved dodos of soft tissue including plumes on specimens of Confuciusornis and possible protofeathers on Sinosauropteryx. The two new animate beings, named Protarchaeopteryx robusta ( robust foremost ancient-wing ) and Caudipteryx zoui ( Zou Jiahua # 8217 ; s chase plume ) , besides have plumes preserved but add to the list of unbelievable Liaoning finds for a different ground: they are, harmonizing to the writers, the first dinosaurs preserved with unambiguous plumes that are non in the clade Aves, the clade normally referred to as # 8220 ; birds. # 8221 ; The animate beings were covered with plumes, including down, like those of Archaeopteryx and modern birds, with cardinal rachis, radiating vanes and barbules. Unlike those of Archaeopteryx and all winging birds, the primary plumes of Protarchaeopteryx and Caudipteryx were symmetrical, bespeaking they were incapable of sustained powered flight. The plumes covered their organic structures and formed # 8220 ; wings # 8221 ; on their forelimbs and big fans on their dress suits. Protarchaeopteryx and Caudipteryx were about turkey-sized with long legs suited for Swift running. Neither animate being had the to the full reversed foremost toe held near to the land that Archaeopteryx and modern birds have, an version for roosting. Alternatively, the toe was farther up the pes in a place typical of non-avian bird-footed dinosaur dinosaurs. Both animate beings had U-shaped furculas typical of those known from both avian and non-avian bird-footed dinosaurs. Both dodos were found with gastroliths, or # 8220 ; tummy rocks, # 8221 ; like those found in modern birds and some predentatan dinosaurs, but neer earlier found in bird-footed dinosaurs. Both animate beings had gastralia, or belly ribs, typical of those of non-avian bird-footed dinosaurs and early birds. The dentition of Protarchaeopteryx were serrated, unlike those of all known birds, including Archaeopteryx. The dentition of Caudipteryx were confined to the premaxillary, and were linear and spike-like, alone among all bird-footed dinosaurs. Both animate beings had the semilunate ( lunula ) shaped bone in the wrist typical of birds and other maniraptoran bird-footed dinosaurs such as the dromaeosaurs, which includes animate beings like Velociraptor. Their unfused fingers besides had the typical bird-footed dinosaur and early bird phalangeal expression ( figure of castanetss in the fingers ) of 2-3-4-x-x. All fingers supported claws, with keratinous sheaths preserved on two claws of Protarchaeopteryx. The tail of Protarchaeopteryx was comprised of up to 28 vertebrae, similar to non-avian bird-footed dinosaurs, while Caudipteryx # 8217 ; s tail was comprised of 22 vertebrae like that of Archaeopteryx. The forelimbs of Protarchaeopteryx were shorter, compared with the thighbone, than in birds but was longer than those of long-armed non-avian coelurosaur bird-footed dinosaurs such as the dromaeosaurs. The forelimbs of Caudipteryx were shorter comparative to the thighbone than in both birds and non-avian coelurosaurs. Because of the deficiency of the perching version and the other synapomorphies that unambiguously identify Aves ( non listed here for brevity ) , both animate beings have been placed outside of the birds. The dodos do, nevertheless, have the characters typical of bird-footed dinosaur dinosaurs. On the dinosaur household tree, Caudipteryx is placed really near to, but more crude than, Archaeopteryx and all other birds while Protarchaeopteryx is considered to be closely related to the dromaeosaurs. Many paleontolgists and partisans feel the presence of confirmed plumes on non-avian dinosaurs should take any tarriance uncertainties that birds are dinosaurs. # 8220 ; It is a historic minute when a contention is resolved, # 8221 ; Dr. Phil Currie of the Royal Tyrrell museum in Alberta, Canada, said at a National Geographic Society intelligence conference. # 8220 ; This shows that dinosaurs are non nonextant, but are well-represented by 10,000 species of birds. # 8221 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; Mentions: Qiang, Ji, Phillip J. Currie, Mark A. Norell and Ji Shu-An. 1998. Two feathered dinosaurs from northeasterly China. Nature June 25, 1998. # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; Copyright? 1998 by Jeff Poling. Feathered non-avian bird-footed dinosaurs treatment Jeff Punting # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; # 8212 ; From: # 8220 ; Thomas R. Holtz, Jr. # 8221 ; 318