- Bird ichnology
Bird
ichnology is the study ofavian life traces inornithology andpaleontology . Such life traces can includefootprint s,nest s,feces andcoprolith s. Scientists gain insight about thebehavior and diversity of birds by studying such evidence.Ichnofossil s (or ichnites) are especially important for clarifying theevolution and prehistoric diversity oftaxa . These cannot usually be associated with a particulargenus , let alonespecies of bird, as hardly ever they are associated with fossil bones. But it is possible to group them intoichnotaxa based on their morphology (form). In practice, the details of shape that reveal the birds' behavior or biologic affinity are generally given more weight in ichnologic classification.Bird ichnofossils
These fossil traces of birds are sometimes hard to interpret correctly, especially when they are from the
Mesozoic when the birds'dinosaur ian relatives were still in existence. Nests at least ofNeornithes are usually quite easy to identify as such due to the unique structures of their eggshells (which incidentally are not trace fossils); there is some uncertainty as regards the origin of certainMesozoic eggshells, which makes nests of this age problematic.Mesozoic fossil footprints are hardest to attribute. "Proto-bird" and related theropod feet were very much alike; non-avian theropod tracks such as the ichnogenus "
Grallator " were initially attributed toratites because in the early 19th century when these were described, the knowledge about dinosaurian diversity was marginal compared to today, whereas ratites were well-known. Also, under thecreationist dogma, scientists would believe that e.g.rhea s had been around for all eternity. In theJurassic andEarly Cretaceous , juvenile non-avian theropods left very birdlike footprints. Towards the end of the Cretaceous, the tracks of aquatic birds are usually recognizable due to the presence of webbing between the toes; indeed, most avian ichnotaxa fall into this group. However, giant flightless birds also existed by that time, as evidenced by "Gargantuavis "; if theGastornithidae were indeed close toAnseriformes , their lineage must also have been distinct by then. Such footprints may resemble those of non-avian theropod or evenornithopod dinosaurs. Among the former, theOrnithomimiformes (= "Arctometatarsalia" "sensu stricto") were convergent to ratites in many respects, including the feet, and it is impossible to tell if some large bird-like footprints from the Late Cretaceous are from an ornithomimiform or a giant bird, without associated bone material. [Wright (2004)]Footprints
There exist documented tracks that appear avian since the
Late Triassic , by some 55 million years predating the first proper evidence that very birdlike theropods were present. The Late Triassic and early-midJurassic tracks have been assigned to the ichnogenera "Trisauropodiscus" and "Aquatilavipes". Few scientists would go as far though to consider these traces evidence that birds evolved much earlier than generally believed, and perhaps not from theropod dinosaurs as per today's mainstream opinion.Footprints of at least
Neornithes can be distinguished by several features:
* if ahallux is present, it is directed straight backwards or nearly so.
* the second to fourth (front) toes have a wide angle between them (generally 90-180° or so)
* due to Neornithes having a completely fusedtarsometatarsus (the "lower leg", actually the ankle and midfoot bones) they have no heel pads (except large terrestrial birds)It is notable that
Heterodontosauridae are known from the localities and times when the first avian-looking footprints started to appear. These small ornithopod dinosaurs were entirely unbirdlike, except for theirornithischia npelvis and a tarsometatarsus strongly convergent to that ofEnantiornithes . Though some details remain unresolved, it is far more plausible that "Trisauropodiscus" etc were made by a "Heterodontosaurus "-like animal rather than some sort of bird.*†"Trisauropodiscus" (Early Jurassic? of Stormberg, South Africa):Avian? Non-avian theropod (juvenile "
Grallator ")?
*†"Archaeornithipus" (Late Jurassic/Early Cretaceous of Soria, Spain):No hallux; Avian?
*†"Aquatilavipes" (Early Cretaceous of Canada, E Asia ?and South Dakota, USA -? Anacleto Late Cretaceous of Sierra Barrosa, Argentina):5-6 x 4-5 cm (h/v). Toes long, narrow, small webs; no or very small hallux; T2-T4 100-140°; toe pads; step 20 cm. Avian: "Patagopteryx"? shorebird?
*†"Fuscinapedis" (Woodbine Early Cretaceous of Denton County, Texas):35 x 35 cm (h/v). Toes long, wide; no hallux; T2-T4 110°; toe pads; step 208cm. Avian: giant flightless bird?
*†"Goseongornipes" (Jindong Early? Cretaceous of Goseong County, South Korea):4-4.5 x 3-3.5 cm (h/v w/o hallux). Toes long, thin, T3-T4 small webs, T2 shorter; hallux backwards and high; T1-T4 220°; T2-T4 140-150°. Avian: shorebird - "Geongsangornipes" is "lapsus"
*†"Jindongornipes" (Jindong Early? Cretaceous of Goseong County, South Korea):6.5-7.5 x 5-6 cm (h/v w/o hallux). Toes long, thin, unwebbed, T2 shorter; hallux backwards, high; T1-T4 225°; T2-T4 95-160°; toe pads. Avian: shorebird
*†"Koreanaornis" (Early Cretaceous of Korea):2.5-3.5 x 2.5-3 cm (h/v w/o hallux). Toes long, thin, unwebbed; hallux backwards, high, very small; T1-T4 180; T2-T4 90-135°; toe pads. Avian: shorebird
*†Ichnogen. indet. (Jindong Early? Cretaceous of Goseong County, South Korea):2.3 x 3.5 cm (h/v). Toes narrow, unwebbed, T2+T4 shorter; no hallux; T2-T4 75-80°. Avian? perching bird?
*†"Magnoavipes" (Early/Middle Cretaceous of Texas, ?and Israel -? Late Cretaceous of Korea):25 x 20 cm (h/v). Toes long, very thin; no hallux; T2-T4 109-118°; step 200-217cm. Avian?
*†"Pullornipes" (Early Cretaceous of China):3.3-5.1 x 3.3-4.7 cm (h/v w/o hallux). Toes long, narrow, unwebbed; hallux small, high, backwards and inwards; T1-T4 270-320°, T2-T4 88-141°; step c.15 cm. Avian: shorebird?
*†"Shandongornipes" (Tianjialou Early Cretaceous of Junan County, China):6 x 9 cm (h/v). Toes long, thin, unwebbed; hallux backwards, some zygodactyl; T1-T4 220°; T2-T4 135°; toe pads. Avian: cursorial bird
*†"Uhangrichnus" (Haman Early - Uhrangi Late Cretaceous of SW Korea):c.4 x 3.7 cm (h/v). Toes long, narrow, fully webbed; no hallux; T2-4 c.100°. Avian: waterbird
*†"Barrosopus" (Anacleto Late Cretaceous of Sierra Barrosa, Argentina):3.5 x 3 cm (h/v). Toes narrow, unwebbed, T2 separated (higher); no hallux; T2-T4 100-120°; step 20 cm. Avian?
*†"Sarjeantopodus" (Lance Late Cretaceous of Niobrara County, USA):c.9 x 9 cm (h/v). Toes long, thin; hallux backwards; T1-T4 c.215°; T2-T4 c.150°; Toes webbed, no distinct toe pads. Avian: shorebird
*†"Saurexallopus" (Late Cretaceous of WC USA):30 x 25-30 cm (h/v). Toes long, thin; hallux sideways; T1-T4 130-170°; T2-T4 90°; deep heel; toe pads. Avian?
*†"Yacoraitichnus" (Late Cretaceous of Quebrada del Tapón, Argentina) - "Yacoriteichnus" is "lapsus":No hallux. Avian: enantiornithine? neornithine (galliform)?
*†"Patagonichnornis" (Cretaceous of Ingeniero Jacobacci, Argentina) - "nomen nudum ":Avian: shorebird?
*†"Iranipeda" (Paleocene of Iran) - may be same as "Gruipeda"
*†"Presbyorniformipes" (Green River Early Eocene of Utah, USA):Web impressions present; Avian: presbyornithine?
*†"Charadriipeda" (Late Eocene of Trans-Pecos Texas, USA):Web impressions present; Avian: anseriform?
*†"Ornithoformipes" (Puget Group Late Eocene of Kummer, USA [Similar footprints, now lost, were reported from roughly contemporary strata in France in the 19th century: Buffetaut (2004).] ):c.27 x 32 cm (h/v). Toes long, wide; no hallux; T2-T4 65°; deep heel; toe pads. May be from "Gastornis "; validity disputed. [Patterson & Lockley (2004)]
*†"Reyesichnus" (Middle Miocene of Salar del Hombre Muerto, Argentina):Avian: shorebird?
*†"Avipeda" (Copper Canyon Late Miocene of Califormia, USA):Web impressions present; Avian
*†"Roepichnus" (Caños Late Miocene of Almería, Spain):Web impressions present; Avian
*†"Anatipeda" (Miocene of Romania):Web impressions present; Avian: anseriform?
*†"Gruipeda"Ichnofamily Ignotornidae
*†"Ignotornis" (Haman Early Cretaceous of Korea - Dakota Sandstone Late Cretaceous of Colorado, USA, ?and Argentina):6 x 5 cm (h/v w/o hallux). Toes long, narrow, unwebbed or partial small webs, T2 smaller; hallux backwards and high; T1-T4 220°, T2-T4 130-145°; toe pads; step 33 cm. Avian: "Neuquenornis"? shorebird?
*†"Hwangsanipes" (Uhangri Late Cretaceous of South Korea):x. 7 x 6 cm (h/v w/o hallux). Toes long, narrow, T2+3 partially, T3+4 fully webbed; hallux large; 1-4 c.225°; T2-4 c.110°. Avian: shorebirdEggs (ootaxa)
[Eggs are no longer considered to be ichnofossils. This section should be used as the basis for a different article.]
*†"Oolithus" (Late Jurassic of England) - avian?
*†"Dispersituberoolithus" (Oldman Late Cretaceous of S Alberta, Canada) - neornithine?
*†"Gobioolithus" (Late Cretaceous) - paleognath?
*†"Subtiliolithus" (Late Cretaceous of Mongolia)
*†"Tristraguloolithus" (Oldman Late Cretaceous of S Alberta, Canada) - galliform (cracid)?
*†"Ornitholithus" (Late Paleocene of Spain - Early Eocene of France) - presumably from "Gastornis "
*†"Incognitoolithus" (Eocene of North America) - ratite?
*†Type A ("aepyornithoid") eggs (Tsondab Early Miocene of Namibia - Pliocene of Asia) - ratite?
*†"Namornis" (Middle Miocene of Namibia - Late Miocene of Kenya) - ratite?
*†"Diamantornis" (Middle Miocene of Namibia - Late Miocene of UAE and Kenya) - ratite?
*†"Mediolithus" (Eocene of Germany)
*†"Psammornis" - may be from "Eremopezus" or "Struthio"
*"Extant genera with named oospecies"
**"Struthio " - includes "Struthiolithus"ee also
*
Fossil birds
*Feathered dinosaurs
*Origin of birds
*Veterovata Footnotes
References
* (2004): Footprints of Giant Birds from the Upper Eocene of the Paris Basin: An Ichnological Enigma. "Ichnos" 11(3-4): 357-362. doi|10.1080/10420940490442287 (HTML abstract)
* (2002): Zur Archaeopteryx-Nomenklatur: Missverständnisse und Lösung. "J. Ornithol." 143(3): 269–286. [Article in German, English abstract] DOI|10.1046/j.1439-0361.2002.02006.x (HTML abstract)
* (1923): The Supposed Plumage of the Eocene Bird "Diatryma". "American Museum Novitates" 62: 1-4. [http://digitallibrary.amnh.org/dspace/bitstream/2246/3259/1/N0062.pdf PDF fulltext]
* (1995): A feather in amber from the Upper Cretaceous of New Jersey. "American Museum Novitates" 3126: 1-6. [http://digitallibrary.amnh.org/dspace/bitstream/2246/3571/1/N3126.pdf PDF fulltext]
* (2004): A Probable "Diatryma" Track from the Eocene of Washington: An Intriguing Case of Controversy and Skepticism. "Ichnos" 11(3-4): 341-347. doi|10.1080/10420940490442278
* (1930): The Supposed Plumage of the Eocene Diatryma . "Auk" 47(4): 579-580. [http://elibrary.unm.edu/sora/Auk/v047n04/DJVU/P0579-P0580.djvu DjVu fulltext] [http://elibrary.unm.edu/sora/Auk/v047n04/p0579-p0580.pdf PDF fulltext]
* (2004): Bird-Like Features of Dinosaur Footprints. "In:" aut|Currie, Philip J.; Koppelhus, Eva B.; Shugar, Martin A. & Wright, Joanna L. (eds.): "Feathered Dragons: Studies on the Transition from Dinosaurs to Birds": 167-184Verify source|date=November 2007 . Indiana University Press. ISBN 0253343739
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