New Papers on 34th Street

["Jerry D. Harris" <jharris@dixie.edu>]

Oooooo, holiday movies...!  Thanks to Denver Fowler, Lee Garrison, and Jay 
Nair for bringing some of these to my attention!



Burnham, D.A. 2007. Archaeopteryx -- a re-evaluation suggesting an arboreal 
habitat and an intermediate stage in trees down origin of flight. Neues 
Jahrbuch für Geologie und Paläontologie Abhandlungen 245(1):33-44.

ABSTRACT: The fossil-Iagerstätte of the Upper Jurassic Solnhofen Formation 
contains the earliest known specimens of Archaeopteryx. The paleoecology 
that was indigenous for these archaeopterygian birds is not well known. The 
marine Solnhofen Formation also included other such terrestrial fliers as 
pterosaurs and insects. These volant (i. e., able to fly) taxa along with 
continental plant material were likely blown over the marine waters by 
storms some distance from their natural habitat. These terrestrial organisms 
could only have originated from nearby landmasses with freshwater that 
supported a open forests of conifers and other gymnosperms. This habitat was 
ideal for the skeletal adaptations seen in Archaeopteryx in which its' 
climbing ability far outweighed its putative cursorial attributes. Moreover, 
these archaeopterygian birds were constructed primitively compared to 
flapping flight mechanisms of Recent birds, further suggesting arboreal 
features in archaeopterygian birds were indicative of their lifestyle. With 
a primitive wing beat, Archaeopteryx represents an intermediate form between 
gliders and flapping fliers.


    There are some other papers of interest in the same volume (the 
proceedings of the 4th Symposium on Lithographic Limestone & Plattenkalke --  
see 
http://www.ingentaconnect.com/content/schweiz/njbgeol/2007/00000245/00000001), 
including one on the pterosaur _Ctenochasma_, but I don't have any of them 
yet.




Ferrusquia-Villafranca, I., Bravo-Cuevas, V.M., and Jiménez-Hidalgo, E. 
2007. Xochixtlapilco dinosaur ichnofauna, Middle Jurassic of Oaxaca, 
southeastern Mexico: description and paleontologic significance. 
Contributions in Science of the Natural History Museum of Los Angeles County 
515:1-40.

ABSTRACT: The Xochixtlapilco Dinosaur Ichnofauna was recovered from 
fine-grained, red phyllarenitic strata of the Middle Jurassic Tecocoyunca 
Group partim, which was laid down in a coastal lagoon, and dated as Early 
Bajocian-Early Bathonian on the basis of ammonites. The site lies in the 
Oaxacan Mixteca, southeastern Mexico. The ichnofauna chiefly consists of 
small footprints, whose makers are referred to as a ''basal coelurosaur'' 
(Morphotype A tracks); an undescribed sauropod taxon, probably of family 
rank (Morphotype C tracks); and an ankylopollexian ornithopod (Morphotype D 
tracks). There is also a single large footprint made by an ?allosaurid 
carnosaur (Morphotype B track). This small but relatively diverse ichnofauna 
is the southernmost record of Jurassic dinosaurs in North America, and adds 
a new fauna to the meager record of dinosaurs in Middle America.
During the Jurassic the Mixteca territory (~Mixteca Terrane) was one of 
several small continental crust blocks laid down in the 
inter-American/African space, as Pangea became disassembled. Ecologically 
such a scenario corresponded to an isolated setting where limited space and 
resources might have induced selective pressures toward small size, 
especially to the primary consumers and associated predators; it also 
shielded the island fauna from competition and exchange with neighboring 
continental faunas. Nonetheless, the Xochixtlapilco dinosaur fauna shows a 
closer biogeographic/phylogenetic resemblance to the North American faunas 
than to the South American or African faunas; however, the meaning of this 
fact can not be fully ascertained at present because of the Xochixtlapilco 
fauna's small size.

This one is available free at 
http://www.nhm.org/research/publications/index.html#pdf.




Elliott, W.S., Jr., Suttner, L.J., and Pratt, L.M. 2007. Tectonically 
induced climate and its control on the distribution of depositional systems 
in a continental foreland basin, Cloverly and Lakota Formations (Lower 
Cretaceous) of Wyoming, U.S.A. Sedimentary Geology 202(4):730-753. doi: 
10.1016/j.sedgeo.2007.09.001.

ABSTRACT: Continental sediments of the Cloverly and Lakota Formations (Lower 
Cretaceous) in Wyoming are subdivided into three depositional systems: 
perennial to intermittent alluvial, intermittent to ephemeral alluvial, and 
playa. Chert-bearing sandstones, conglomerates, carbonaceous mudrocks, 
blocky mudrocks, and skeletal limestones were deposited by perennial to 
intermittent alluvial systems. Carbonaceous mudrocks contain abundant wood 
fragments, cuticle and cortical debris, and other vascular plant remains 
representing deposition in oxbow lakes, abandoned channels, and on 
floodplains under humid to seasonal conditions. Intraformational 
conglomerates, sandstones, bioturbated and blocky mudrocks with caliche 
nodules, and bioturbated limestones characterize deposition in intermittent 
to ephemeral alluvial systems. Bioturbated limestones are encased in 
bioturbated mudrocks with abundant pseudo-slickensides. The presence of 
caliche nodules in some of the blocky to bioturbated mudrocks is consistent 
with supersaturation and precipitation of calcium carbonate from groundwater 
under semi-arid conditions. Caliche nodules, pseudo-slickensides, and 
carbonate-rich floodplain sediments are interpreted to have been deposited 
by intermittent to ephemeral alluvial systems under seasonal to semi-arid 
climatic conditions. Laminated mudrocks, siltstones, vuggy carbonates, 
bedded to nodular evaporites, pebbly mudrocks, and diamictites were 
deposited in evaporative alkaline lakes or playas. Pebbly mudrocks and 
diamictites are interpreted to represent deposition from channelized and 
unchannelized hyperconcentrated flows on a playa, resulting from intense 
rain events within the basin.

The areal abundance and distribution of these depositional systems change 
systematically across the overfilled portion of the Early Cretaceous 
Cordilleran foreland basin in Wyoming. The lower part (A-interval) of the 
Cloverly and Lakota Formations is characterized by deposits of perennial to 
intermittent rivers that existed 300 to 1000 km east of the Sevier 
fold-and-thrust belt. Proximal to the Sevier fold-and-thrust belt, the 
A-interval of the Cloverly Formation and upper Ephraim Formation of the 
Gannett Group are typified by deposits of intermittent to ephemeral rivers 
and their associated floodplains. In the middle part (B-interval) of the 
Cloverly Formation, intermittent to ephemeral alluvial systems expand to 600 
km into the basin. The upper part (C-interval) of the Cloverly Formation is 
characterized by playa deposits in the Bighorn and Wind River Basins and 
intermittent to ephemeral alluvial deposits along the front of the ancestral 
Sevier Mountains. Deposits of perennial to intermittent alluvial systems in 
the C-interval of the Cloverly and Lakota Formations are restricted to the 
Black Hills region, almost 900 km to the east of the Sevier Mountains. The 
change in the areal distribution of depositional systems through time within 
this continental foreland basin may be attributed to the development of a 
rain shadow associated with the uplift of the Sevier Mountains in the Early 
Cretaceous.



Hu, Y.-M., Meng, J., and Clark, J.M. 2007. A new Late Jurassic docodont 
(Mammalia) from northeastern Xinjiang, China. Vertebrata PalAsiatica 
45(3):173-194.

ABSTRACT: A new genus and species of docodontid (Docodonta, Mammalia), 
Acuodulodon sunae, represented by a partial left lower jaw and dentition, is 
described. It is from the upper part of the Shishugou Formation in the 
Wucaiwan area of the Junggar Basin in northeastern Xinjiang, China, with an 
estimated age of 159~161Ma (Oxfordian, early Late Jurassic). The new mammal 
is typical of docodonts in having a cusp b in front of cusp a, a cusp c 
distolingual to cusp a and a cusp g mesiolingual to cusp a on lower 
molariforms. Differing from other docodonts, it has no cusp a or crest b-a 
developed on lower molariforms. Unique among docodonts, cusps a and c of the 
new animal maintained their sharpness while cusp g and crest b-g wore away 
fast, indicating that both shearing and crushing/grinding occurred in the 
chewing cycle and probably last for most of the life span of the animal. 
Phylogenetic analysis of a data matrix with 24 lower molariform characters 
across 15 taxa recovers a monophyletic Docodonta, which has distinct 
diagnostic characters in lower molariforms. Within docodonts, Docodon and 
Borealestes are successively basal to other docodonts; Acuodulodon and 
Itatodon + (Simpsonodon, Castorocauda+(Tegotherium + Sibirotherium)) form a 
monophyletic dade. Tegotheriid genera are nested within Docodontidae, but a 
monophyletic tegotheriid dade composed of Tegotherium, Sibirotherium, 
Itatodon, and Tashkumyrodon is not recovered. The dentary of Acuodulodon is 
typical of docodonts. It has a shallow postdentary trough and a wide and 
sharp medial ridge, both of which do not extend onto the medial side of the 
condylar peduncle, indicating looser contact between postdentary bones and 
the dentary than in morganucodontids, a more derived condition in the 
evolution toward the definitive mammalian middle ear.



Lastly -- not really new, but -- you can get for a few bucks booklets of 
reprints of _Scientific American_ papers on various fossil groups -- they've 
collected them from back issues into subject-specific booklets.  There's one 
entitled "Prehistoric Beasts" 
(http://www.sciamdigital.com/index.cfm?fa=Products.ViewIssue&ISSUEID_CHAR=68DFB6AE-A91C-4A1A-DF98AC41A3C5C4CF) 
and one entitled "Dinosaurs and Other Monsters" 
(http://www.sciam.com/special/toc.cfm?issueid=20) -- note that there are 
some duplicate papers between the two.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jerry D. Harris
Director of Paleontology
Dixie State College
Science Building
225 South 700 East
St. George, UT  84770   USA
Phone: (435) 652-7758
Fax: (435) 656-4022
E-mail: jharris@dixie.edu
and     dinogami@gmail.com
http://cactus.dixie.edu/jharris/

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"Machine. Unexpectedly, I'd invented
a time"
              -- Alan Moore

"Easy. Just touch the match to"
              -- Ursula K. Le Guin

"Batman Sues Batsignal: Demands
Trademark Royalties."
              -- Cory Doctorow