Chirotherium trackways from the Middle Triassic of Guizhou, China (free pdf)

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com

A new paper in Ichnos:


Lida Xing, Hendrik Klein, Martin G. Lockley, Jianjun Li, Jianping
Zhang, Masaki Matsukawa & Jiafei Xiao (2013)
Chirotherium Trackways from the Middle Triassic of Guizhou, China.
Ichnos 20 (2):  99-107
DOI:10.1080/10420940.2013.788505
http://www.tandfonline.com/doi/full/10.1080/10420940.2013.788505#.UaJ9CkC1FcQ

pdf available at:
http://www.xinglida.net/pdf/Xing_et_al_2013_Chirotherium_Trackways.pdf

Triassic tetrapod footprints from China are less well known than those
from the Jurassic and Cretaceous. Archosaurian trackways of the
ichnogenus Chirotherium were found in the Middle Triassic Guanling
Formation in Zhenfeng County (Guizhou Province) at the southwestern
edge of the Yangtze plate in the early 1960s but were not correctly
identified and adequately described until 40 years later. Here we give
a detailed re-description and review of the trackways, which are known
from two localities near the villages of Niuchang and Longchang. They
occur on the bedding surface of a mud-cracked argillaceous dolostone
deposited in a near-shore, shallow-water environment. Their morphology
and general trackway pattern indicate that they pertain to the
ichnospecies Chirotherium barthii, well known from Middle Triassic
track surfaces of Europe, North and South America, and northern
Africa. A peculiarity of the trackways from China are the low pace
angulation and stride length, reflecting slow-moving trackmakers,
which were basal crown-group archosaurs, possibly early
representatives of the dinosaur-bird line or, alternatively,
stem-group crocodylians. These tracks constitute the only chirotheriid
record known from Asia thus far and indicate a Pangea-wide
distribution for this ichnotaxon. Biostratigraphically, assemblages
with C. barthii are characteristic of the early Anisian, an age
assignment already supported for the Guanling Formation based on
conodont and bivalve biostratigraphy. In contrast, however,
radiometric data from an interlayered ash bed indicate a Ladinian age.