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330 SMITHSONIAN CONTRIBUTIONS TO PALEOBIOLOGY ically. Because most analyses (e.g., Chiappe, 1995; Sanz et al., 1995) suggest that these birds are more closely related to modem birds than is Archaeopteryx, what relevance do these new discoveries hold for the debate on avian origins? The discussion began with L.M. Chiappe, who suggested that "the role of the Cretaceous avian radiations, in my point of view, is very clear. Without disregarding the data that Archaeopteryx provides, I think that we actually don't need Archaeopteryx right now, for example, to support the idea that birds are descended from theropod dinosaurs. ...We have enormous support from this Cretaceous radiation." Likewise, P.C. Sereno argued for the critical role played by the new discoveries of Cretaceous birds: "Recently, even aside from these possible Late Jurassic-earliest Cretaceous forms, new birds have presented other combinations of characters that include even more advanced avian characters while still retaining things like gastralia and things that we've never seen in birdlike creatures before." Some participants saw the Cretaceous avian radiations as helping to refine and redefine the role that Archaeopteryx plays in the debate. For example, Elzanowski suggested that "barely anything points so much to the central role of Archaeopteryx— its central position in [the] evolution of birds—than this record of Sinornis and Confuciusomis. [Sinornis is] perfectly intermediate between Archaeopteryx and more modem birds.... So, if let's say Sinornis is intermediate between modem birds and Archaeopteryx, therefore, by purely logical reasoning, Archaeopteryx has to be central to the evolution of birds in morphological terms." For Sereno, the combination of Archaeopteryx and the Early Cretaceous birds presents "really a nice phylogenetic situation. I think for a cladist to look at Archaeopteryx, it additionally presents a strong argument for the origin of birds because it has so few autapomorphies. When you put it up on a cladogram, you try to see what are the characters that are unique to itself and to help to map its phylogenetic information. There are so few that we almost want to call it a metataxon (something that you can't actually link the specimens together by [apomorphic] features). I think that's the important thing, to reiterate what Luis [Chiappe] is saying, that we've got confirmatory evidence from other animals." G.S. Paul responded that "it is very possible that morphologically Archaeopteryx basically is a theropod dinosaur with wings It is very possible thai Archaeopteryx maybe was allied with dromaeosaurs or was a completely independent development from birds. On the other hand, what Paul [Sereno] just said is also tme—it's so primitive that it could be at the base of the bird radiation In a way, we really don't know whether Archaeopteryx has a central role or not—we do not have the information yet." 3. THE THEROPOD HYPOTHESIS AND THE "TIME PROBLEM" Although the theropod hypothesis has been the most popular one for more than twenty years, it has always faced what may be regarded as "the time problem" (Witmer, 1995; see also Fe duccia, 1996), namely, the most bird-like of the nonavian theropods (e.g., dromaeosaurids, troodontids, oviraptorosaurs) are younger in age than Archaeopteryx. If the conventional hypothesis is correct, then birds and nonavian coelurosaurs diverged in at least the Jurassic. Where, for example, are the Jurassic dromaeosaurs? How disturbed should we be by this discordance in the fossil record? Does it severely damage the theropod hypothesis, as has been suggested (Tarsitano, 1991; Feduccia, 1994, 1996)? The discussion of this topic was limited. Sereno, who has studied the temporal ranges of theropod clades in conjunction with the pattern of phylogenetic branching, acknowledged that "there is a time discordance between Archaeopteryx and its nearest sister group. But when you look at the overall phylogeny of theropods, there are many time discordances—but also many missing lineages with much greater length than that actually. For example, if we look at the origin of coelurosaurs, we now have radiometrically dated allosaur-like animals for the <strong>Lo</strong>wer Jurassic. We know that there was a coelurosaur lineage at the base of that radiation for which we have no evidence for the Jurassic, essentially until the Late Jurassic. So, we're missing maybe 20-30 million years of early coelurosaur evolution before we get to the point where we were talking about Archaeopteryx and these other things. So, it's not that unusual. It seems that small theropods in general are your worst case extreme for taphonomists, because you don't have the option usually of lake beds or near-shore marine sedimentary localities, but neither do you have the size that will often carry you through in a fluvial environment. So, you fall in-between the cracks in a very poor record." 4. THE SIGNIFICANCE OF Protoavis FOR THE DEBATE From the time of its discovery, Archaeopteryx was regarded as both the oldest and the most primitive bird. Reports of Triassic avian remains from Texas (Chatterjee, 1987, 1991, 1995, this volume) would appear to challenge one or both of these claims. According to Chatterjee's (1991) cladogram (see also Kurochkin, 1995), Protoavis is closer to the modem radiation than is Archaeopteryx. In other words, Archaeopteryx would remain the basal member of Aves, but not the oldest. Thus, what is the significance—even relevance—of Protoavis for the debate on avian origins? Obviously it would make the time problem of topic three, above, much worse, telescoping much of theropod cladogenesis into the Norian or even Camian. Otherwise, Protoavis might behave phylogenetically much like the components of the Cretaceous avian radiation (topic two, above). The discussion began with S. Chatterjee, who saw the time problem as less of an issue, suggesting that "we're caught up in a stratophenetic approach We are very content with Archaeopteryx—this is the primitive one. You can derive anything from it. When the new evidence comes, look at it. <strong>Lo</strong>ok at the bones. I think what it tells us is that, like mammals, there was a
NUMBER 89 very bush-like radiation of birds." Chatterjee argued that the real significance of Protoavis resides in its prospects for establishing a skeletal definition of birds: "Once you define it, then there is no problem. Vox Archaeopteryx or for birds it is really a circular argument: we are defining on feathers. Do we define mammals on hair? No. ...We need some practical, tangible evidence preserved in the fossils so that we can call it 'bird.' Once you define it, then you can see whether Archaeopteryx falls under the definition or not The time has come: we have to give the osteological definition of birds. For that matter, I think Protoavis really has a much, much better chance. You can define birds on the basis of the quadrate. You can define birds on the basis of the cheek region If you can document that the orbit and the two temporal openings are confluent, it is a bird." Sereno stated that the significance of Protoavis cannot be adequately assessed until the professional community takes a serious approach to the fossils: "It seems that most people ignore Protoavis, and I think that this is a sad situation. I think there's a lot of very different opinions about what Protoavis is, and some of these have been aired. [But] if we're going to move on the significance of Protoavis, it probably would be in having some type of a consortium with the fossil material, with people actually commenting on what they think it is in a serious-science forum." 5. THE ORIGIN OF BIRDS VERSUS THE ORIGIN OF FLIGHT In some formulations (Tarsitano, 1991; Feduccia, 1993, 1996; Feduccia and Wild, 1993), the origin of flight and the origin of birds are inextricably united: flight "from the ground up" with the theropod hypothesis and flight "from the trees down" with more basal archosaurs. The protocol appears to be to develop a concept of the hypothetical proavis based on one's notion of the origin of flight and then survey the animal kingdom for a match; that is, the functional inference precedes the phylogenetic inference. The intent of this topic is not to examine the origin of flight, but rather to discuss the necessity of coupling these two issues. In other words, what is the relationship of phylogenetic inference to functional inference? The discussion began with Elzanowski, who proposed, "the strict coupling of theropod/'from-the-ground-up' and alternative-hypotheses/'from-the-trees-down' is not really warranted. I think that the discussion of the taxonomic origin of birds should be decoupled from the mechanics—the evolutionary mechanism—of the origin of flight. As all of us probably agree, we really don't know, in a strict sense, the ancestor of birds—we can't agree which are the closest theropod relatives of birds. We have no idea [of their] size or what those ancestors looked like. We know that they certainly were smaller than basically all the dinosaurs we have fossils of." Elzanowski argued that, as observed in mammals, small theropod dinosaurs would have had much more "flexible ankles" than large dinosaurs. This is "a known generalization— There is no reason to ques 331 tion that there were arboreal or slightly arboreal theropods that would just climb on the tree or mn on the tree trunk and [then] just jump and glide from the tree trunk." Chiappe agreed that the two should be decoupled, saying, "The kind of data that we have is completely different. For the origin of birds, [it] is exclusively phylogenetic. We have a lot of data. We have fossils we can measure, look at, and examine. The origin of flight is a totally different question—a very interesting one, but the kind of data that we have is certainly ten times more speculative. ...First, we should come up with an idea, a notion, about the origin of birds,... and then try to see how we can explain the origin of flight within the framework of that particular idea." Sereno likewise argued "that the two are very separate, because when you start looking at the problem phylogenetically, only some of the characters that are linking these animals together into an evolutionary sequence actually are related to flight. Some of the most interesting things are the characters that were co-opted but were not evolved for flight in the first place. We have the extraordinary opportunity, with the great functional work that's being done and a series of fossils, to go at this functional transformation like we cannot in the case of bats and pterosaurs. We can actually tease apart the functional sequence, but all of the characters are not related to that functional sequence, so the two are pretty separate." P. Wellnhofer provided some important cautionary remarks about, again, over-reliance on Archaeopteryx, commenting that "we have to be careful in our conclusions. I think it's not so important what lifestyle Archaeopteryx as an animal really had. Maybe [it] could even climb or sit on a tree or on a tree branch or something like that. I think what's more important is the general architecture of the skeleton. The lifestyle of Archaeopteryx [itself] can be quite different from what we suggest." 6. THE VALIDITY OF "NONSTANDARD" HYPOTHESES As in probably all areas of human endeavor, science tends to eschew the iconoclastic in favor of familiar things from familiar sources. In the present case, the "nonstandard" views of Paul and Olshevsky seem to be examples of this phenomenon in that they reverse the typical ancestor-descendant relationship, derive from individuals that are outside the "fold" of university and museum professionals, and have not been published in the conventional outlets. As mentioned, these views have been almost totally ignored. Ironically, both views agree with the current orthodoxy that birds and theropods are very closely related and, moreover, present the advantage that the time problem disappears. The intent of this topic is to examine the status of these views in the current debate. The discussion was limited to a statement by L.D. Martin: "One of the things about this conference that I've found extremely interesting is how many of the papers that were presented today could be taken to support Gregory Paul's socalled 'nonstandard' hypothesis. I would say he's getting so much support that we can view it as a school—'the Paulian
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SMITHSONIAN CONTRIBUTIONS TO PALEOB
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ABSTRACT Olson, Storrs L., editor.
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EARLY WATERFOWL (ANSERIFORMES) AND
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v m SMITHSONIAN CONTRIBUTIONS TO PA
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localities, all of them situated in
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Bone of Sus scrofa Linnaeus, introd
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duboisi are larger than the largest
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8 iver (1897) but afterward were tr
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10 SMITHSONIAN CONTRIBUTIONS TO PAL
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16 Cor. Hum. Uln. Cpm. Fern. Tbt. T
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20 sometatarsus are proportionally
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34 ability in such a way that it ca
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42 2km SMITHSONIAN CONTRIBUTIONS TO
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Site 13 Research Base ENTRANCE Lowe
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48 the last has unusually slender w
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Comparison of Paleoecological Patte
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NUMBER 89 69 TABLE 1.—Vertebrate
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NUMBER 89 71 Mallorca, probably in
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NUMBER 89 Alcover, J.A. 1989. Les a
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The History of the Chatham Islands'
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NUMBER 89 87 Species Common Name Pe
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NUMBER 89 89 NZA 797,1930,1934 Unco
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NUMBER 89 91 anoramphus spp.), Chat
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NUMBER 89 93 TABLE 2.—Land snails
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NUMBER 89 95 counterparts, with som
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NUMBER 89 population, if such exist
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NUMBER 89 99 FIGURE 11.—Skulls of
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NUMBER 89 101 FIGURE 13.—Lower ma
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NUMBER 89 the Chatham Island Pied O
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NUMBER 89 Locality 9, Western Maung
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NUMBER 89 107 yellowish sand (site
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NUMBER 89 109 ogy. Notornis, supple
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112 SMITHSONIAN CONTRIBUTIONS TO PA
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The Middle Pleistocene Avifauna of
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NUMBER 89 Accordi, B. 1962. La grot
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130 FIGURE 1.—Map showing locatio
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132 Cranium Mandibula Scapula Clavi
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Seabirds and Late Pleistocene Marin
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NUMBER 89 141 METHODS Only strictly
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NUMBER 89 143 FIGURE 2.—Area of s
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NUMBER 89 151 FIGURE 10.—Area of
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NUMBER 89 153 FIGURE 12.—Area of
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NUMBER 89 155 the period studied. T
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NUMBER 89 157 Walker, C.A., G.M. Wr
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164 Vl 620 M 570 £ 520 S 470f •
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166 birds, such as the two species
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170 cional Autonoma de Mexico, for
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174 ated with this specimen, see Mi
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The Fossil Record of Condors (Cicon
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NUMBER 89 179 FIGURE 2.—Geographi
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NUMBER 89 181 FIGURE 5.—Vulturida
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NUMBER 89 183 FIGURE 7.—Referred
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Two New Fossil Eagles from the Late
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NUMBER 89 187 TABLE 1.—Measuremen
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NUMBER 89 189 carpal trochlea relat
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NUMBER 89 191 FIGURE 4.—Holotypic
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NUMBER 89 193 We compared the parat
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NUMBER 89 195 FIGURE 6.—Distribut
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NUMBER 89 197 the Florida State Mus
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A New Genus of Dwarf Megapode (Gall
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NUMBER 89 201 lis hypotarsi along t
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NUMBER 89 203 The fossil is larger
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NUMBER 89 205 Clark, George A., Jr.
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A New Genus and Species of the Fami
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NUMBER 89 209 son with other known
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NUMBER 89 211 FIGURE 1.—Argornis
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NUMBER 89 213 AM AL AM AL AM AL AM
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NUMBER 89 215 caput humeri perpendi
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Selmes absurdipes, New Genus, New S
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NUMBER 89 219 FIGURE 2.—Selmes ab
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NUMBER 89 221 Costae: Deformed frag
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A Fossil Screamer (Anseriformes: An
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NUMBER 89 FIGURE 3.—Chaunoides an
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NUMBER 89 227 B C D FIGURE 6.—The
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NUMBER 89 229 FIGURE 9.—Right tib
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The Anseriform Relationships of Ana
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NUMBER 89 233 Subfamily ANATALAVINA
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NUMBER 89 235 mal was found under t
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NUMBER 89 237 tion, with retroartic
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NUMBER 89 FIGURE 7.—Sternum and p
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NUMBER 89 241 der. The bone is very
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NUMBER 89 243 Eocene records of the
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Presbyornis isoni and Other Late Pa
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NUMBER 89 255 FIGURE 1.—Referred
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NUMBER 89 257 vical vertebrae of th
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NUMBER 89 259 (Olson and Parris, 19
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274 America. Science, 214(4526): 12
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276 concerning the amphicoelous str
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278 ment of the radius that are con
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Page 294 and 295: 284 Kurochkin, E.N. 1982. [New Orde
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Page 300 and 301: 290 1991). In this paper we use a "
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