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Not so new papers



I've spent a few hours in the special libraries of the university institutes for biology and geosciences. There I've dug up 2 interesting papers which probably aren't news to many list members, but they are important for my own article, the discussion on which I'll try to open tomorrow*:
 
Gerard Gierlinski (with an accent on the n, like Maryanska): Feather-like Impressions in a Theropod Resting Trace from the Lower Jurassic of Massachusetts, 179 -- 184, in
 
Michael Morales (ed.): The Continental Jurassic, Museum of Northern Arizona Bulletin 60, 1996
 
"ABSTRACT: Restudy of a well known [since 1858!!!] example of a dinosaur resting trace, the famous Hitchcock collection trophy catalogued as AC 1/7, led to a significant, hitherto unreported observation. The trace of the Early Jurassic squatting theropod from Massachusetts contains the pubic-abdominal imprint with the hair- or feather-like impressions. These structures strongly resemble those left by the hairy or feathered body parts of recent mammals or birds, especially their so-called furry feathers."
 
The specimen is classified as Eubrontes minusculus. It consists of the impression of both whole feet (with very short 1st toes), the deep heart-shaped impression of the ischiadic foot (so coelurosaurs are ruled out as the trackmaker, AFAIK) well behind the footprints, and those interesting impressions next to the right foot that were made by the belly. The trackmaker was sitting asymmetrically, with the pubic foot maybe resting on the right foot, as there is no impression of it.
 
Gierlinski organized "Figure 3. [...] b, footprints and the feathered chest impression of Andaean [sic] condor Vultur gyphus, obtained experimentally at the Warsaw Zoo". The only differences to the fossil are: 1. the size; 2. the feather impressions of the condor are in front of the feet, because in Neornithes the breastbone is usually the part of the trunk that extends farthest toward the ground (a faint impression of the keel is present), whereas in more basal theropods these were the pubes and the gastralia just in front of them (as well as the ischia in ceratosaurs and basal tetanurans); 3. there is no ischiadic foot; 4. the condor sat more symmetrically. Figure 3. a is a Chirotherium track with drag marks, provided just in case someone may doubt the integumentary nature of the impressions.
 
A few more quotes:
 
"Pubic-abdominal Imprint with Feather-like Impressions (Figs. 1b, 2)
        [...] The anterior right fragment of [the] abdominal imprint is overprinted by a [sic] second digit of [the] right foot. In other words, it looks like the belly partially overlapped that digit. The pubic-abdominal imprint is rotated outwardly from the trackway midline by 11°. The trackmaker sat irregularly, turning its body slightly to the right side, and leaning the belly partially on the right foot.
        Consequently, the belly did not bear the same weight as the feet and the ischiadic callosity did while in the resting posture. Probably this is responsible for the good preservation of the feather-like impressions. Otherwise, if the belly had been[ ]more heavily imprinted, such delicate traces might have simply disappeared.
        The feather-like impressions are usually more than 1 cm long and mostly grouped near the left margin of the pubic imprint."
 
"In my opinion, feather-like impressions discussed herein are clearly unlike those produced by invertebrates, nor do they resemble drag-marks left by rough skin (Fig. 3a). The drag-marks occur rather outwardly of the impressions of the object which left them. In contrast, these discussed impressions are located inside the pubic-abdominal imprint. In the specimen AC 1/7, a good example of drag-marks occurs beside the left outline of the left metapodium.
        The feather-like impression[s] in the pubic-abdominal imprint strongly resemb[l]e those which have been left by thesoft body covering of mammals and birds (Fig. 3b). They seem to have been made by structures more flexible than scales, thinner than flight feathers, and broader than mammalian hairs. [PROTOFEATHERS!!!!!!] Probably they were similar to the furry feathers of flightless birds, but guessing their exact anatomical nature on the basis of the presented ichnological material would be hazardous. [Indeed, but a few months later Sinosauropteryx was discovered...]
        Some researchers have supposed that some non-avian theropods could be feathered (Bakker, 1975, 1986; Feduccia, 1970; Olson, 1985; Paul, 1988). However, those authors expected that such insulation should be present in small forms, but the resting trace AC 1/7 was not left by a small creature. The values of its pes osteometric ratios II3/II2 and III2/IV1 lie between those of Liliensternus and Dilophosaurus (Farlow and Lockley, 1993, Fig. 2). Applying the Liliensternus and Dilophosaurus proportions of whole body length to foot length, to AC 1/7 footprint size, the trackmaker's length can be estimated as approximately 5 m."
 
So the fossil record of protofeathers extends back to the Early Jurassic, doesn't it?
 
The other paper is a preliminary note on Nomingia gobiensis from a year ago:
 
Rinchen Barsbold, Philip J. Currie, Nathan P. Myhrvold, Halszka Osmólska, Khishigjaw [what a transcription... :-( :-( ] Tsogtbaatar, Mahito Watabe: A pygostyle from a non-avian theropod. The independent evolution of a bird-like tail has been discovered in an oviraptorosaur. Nature 403, 155 (the references extend to the next page) (13 January 2000).
 
Contains a wonderful blue and white drawing by Michael Skrepnick.
 
I won't write much about this, as Nomingia has been named and described in the meantime and has also been discussed onlist. I'll just quote a few things and comment them:
 
"Although the terminal vertebrae of Caudipteryx are not fused, they seem to form a stiffened rod."
"Most non-avian theropods have long tails with elongate (relative length to width) caudal centra, whereas oviraptorosaurs have short tails with short, broad vertebral centra. The minimum counts are 32 for Conchoraptor (GIN 110/19), 27 for Ingenia and 27 for "Oviraptor" mongoliensis. GIN 940824 [ = Nomingia] has only 24 caudals, fewer than any non-avian theropod except Caudipteryx, which has 22."
        I have a guess why this is so: Caudals 23 and 24 are tiny, and 22, 23 and 24 are together just as large as 21. If in Caudipteryx only the last 3 vertebrae are fused, the suture lines may have been overlooked...
 

*It's 22:55 over here, so I may mean today, depending on where you are. :-)