New pterosaur and Mesozoic bird bits

[bh480@scn.org]

From: Ben Creisler
bh480@scn.org

Although these new papers discuss somewhat scrappy 
material, they still should be of interest:

Victoria M. Arbour and Philip J. Currie (2011)
An istiodactylid pterosaur from the Upper Cretaceous 
Nanaimo Group, Hornby Island, British Columbia, Canada.
Canadian Journal of Earth Sciences 48(1): 63-69 (2011)  
doi:10.1139/E10-083  
http://rparticle.web-
p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?
calyLang=eng&journal=cjes&volume=48&year=0&issue=1&msno=e1
0-083

An unusual jaw found in a calcite nodule from Collishaw 
Point, Hornby Island, British Columbia (off the east 
coast of Vancouver Island) represents the first 
definitive pterosaur found in British Columbia, and the 
first istiodactylid from Canada. The nodule was derived 
from the Northumberland Formation (Nanaimo Group), a 
fossiliferous formation known for producing numerous 
plants, invertebrates, sharks, and mosasaurs. The 
pterosaur is represented by the anterior portion of the 
rostrum, including the anterior edge of the 
nasoantorbital fenestra, and numerous small, triangular 
teeth lacking denticles. These teeth are similar in 
overall morphology to the teeth of istiodactylids, but 
are smaller, more numerous, more tightly packed, and have 
proportionately smaller crowns. Although fragmentary, 
this specimen is diagnostic and represents a new genus of 
istiodactylid pterosaur. Its presence in the upper 
Campanian Northumberland Formation makes this the latest 
occurring istiodactylid and extends the stratigraphic and 
geographic range of this enigmatic group of pterosaurs.


A.O. Averianov, E.N. Kurochkin, 2010
A new pterosaurian record from the Cenomanian of the 
Volga Region. 
Paleontological Journal 44 (6): 695-697 
DOI: 10.1134/S0031030110060110 
http://springerlink.metapress.com/content/knu845564u226784
/

A rostral fragment of the dentary symphysis from the 
Cenomanian Melovatka-3 locality (Volgograd Region) is 
referred to the genus Lonchodectes based on the presence 
of elevated jaw borders, longitudinal groove on the 
dorsal surface of the dentary symphysis, and small 
alveoli of teeth, almost uniform in size and widely 
spaced. Lonchodectes sp. from Melovatka-3 is closely 
similar to L. platystomus from the Albian of England. 
This is the first record of the family Lonchodectidae in 
Russia and outside Great Britain. 

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Laura E. Wilson; Karen Chin; Stephen Cumba; Gareth Dyke 
(2010) 
A high latitude hesperornithiform (Aves) from Devon 
Island: palaeobiogeography and size distribution of North 
American hesperornithiforms.
Journal of Systematic Palaeontology (advance online 
publication)
DOI: 10.1080/14772019.2010.502910 
 
http://www.informaworld.com/smpp/content~db=all~content=a9
31439625~frm=titlelink

A new hesperornithiform bird specimen from Devon Island 
in the Canadian High Arctic is represented by three 
cervical vertebrae and is assigned to Canadaga arctica. 
The new specimen is only the second occurrence of C. 
arctica and corresponds in morphology and size to the 
type specimen from Bylot Island, also in the High Arctic. 
This new fossil adds to the record of North American 
hesperornithiforms, which had a well-documented Arctic 
presence. Body size comparisons of all North American 
specimens from the Campanian reveal that the largest 
known hesperornithiforms were from high latitudes, but 
otherwise no clear correlation between body size and 
latitude is apparent. The largest hesperornithiforms 
(Canadaga arctica and Heperornis regalis) are found at 
the highest latitudes, while the smallest forms 
(Baptornis advenus and Parahesperornis alexi) are found 
at the southern extent of the birds' range. Coniornis (a 
medium body-sized genus) is only found in the middle of 
the range. No size trends are discernable within the 
genus Hesperornis or within the species H. regalis. The 
presence of large hesperornithiforms at high latitudes 
may indicate that either strong seasonal distribution of 
resources contributed to larger body sizes at higher 
latitudes, or Campanian thermal gradients along the 
Western Interior Seaway were significant enough to affect 
body size for thermoregulatory reasons (sensu Bergmann's 
rule). The absence of body size trends within mid-
latitude Hesperornis specimens suggests that the climatic 
gradient in the southern portion of the Seaway was not 
strong enough to force morphological evolutionary 
responses, or that character displacement, migration 
and/or other factors affected body size. Sample size and 
the inherent problems of an incomplete fossil record must 
also be considered.  

Evgeny N. Kurochkin; Nikita V. Zelenkov; Alexandr O. 
Averianov; Sergei V. Leshchinskiy (2010) 
A new taxon of birds (Aves) from the Early Cretaceous of 
Western Siberia, Russia.
Journal of Systematic Palaeontology (advance online 
publication)
DOI: 10.1080/14772019.2010.522202 
 
http://www.informaworld.com/smpp/content~db=all~content=a9
31515544~frm=titlelink

In recent decades numerous findings, mostly from the 
Early Cretaceous of China, have changed traditional 
conceptions about the diversity and evolution of the most 
ancient Aves. Findings of Mesozoic birds in Russia are 
extremely rare. Here we describe a new bird from the 
Lower Cretaceous (Barremian-Aptian, Ilekskaya Svita) 
Shestakovo-1 locality (southern Western Siberia, Russia), 
that has also yielded dinosaurs, mammals, crocodiles, 
pterosaurs and lizards. Mystiornis cyrili gen. et sp. 
nov. is based on an isolated metatarsus which displays a 
mosaic of morphological features allowing us to create a 
new order, Mystiornithiformes. Mystiornis has a fully 
consolidated (ornithurine-like) gracile metatarsus with a 
primitive coplanar arrangement of the metatarsals, three 
separate proximal articular facets, and a uniquely 
located distal interosseal canal. It also displays diving 
adaptations previously documented only in Ornithurae.  


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