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Korean Cretaceous dinosaur, bird, and pterosaur tracks in Ichnos



From: Ben Creisler
bcreisler@gmail.com


The new issue of Ichnos is devoted to tracks from the Korea Cretaceous
Dinosaur Coast and other Korean sites:
http://www.tandfonline.com/toc/gich20/current


Papers include:


In Sung Paik, Yong Il Lee, Hyun Joo Kim & Min Huh (2012)
Time, Space and Structure on the Korea Cretaceous Dinosaur Coast:
Cretaceous Stratigraphy, Geochronology, and Paleoenvironments
Ichnos19 (1-2): 6-16
DOI:10.1080/10420940.2012.660404
http://www.tandfonline.com/doi/abs/10.1080/10420940.2012.660404


The stratigraphy, geological ages, and paleoenvironments of the Korea
Cretaceous Dinosaur Coast (KCDC) are reviewed and synthesized in order
to understand the occurrence and diversity of the vertebrate fossils
and track remains in time and space. Various absolute age measurements
obtained during the last decade yield new age data to correlate with
the dinosaur fossil-bearing Cretaceous deposits in Korea. The
radiometric age of the lower (Sindong Group) and middle (Hayang Group)
parts of the Gyeongsang Basin (the largest basin of the KCDC) located
in the eastern part of the KCDC gives dates ranging from Aptian to
Campanian, which is younger than the previous biostratigraphic age
estimates, but the results may be influenced by metamorphism.
Likewise, radiometric dates from the Cretaceous sequence in the
western part of the KCDC give numerical values suggesting a
correlation with the Upper Cretaceous Yucheon Group of the Gyeongsang
Basin. Dinosaur evidence (e.g., tracks, eggs, bones) along the KCDC is
variable in relation to stratigraphy and paleoenvironment. Dinosaur
tracks are preserved mostly in stratigraphically higher Cretaceous
lake margin deposits, whereas dinosaur bones occur mostly in older
Cretaceous floodplain deposits. Most dinosaur eggs are found in Upper
Cretaceous deposits, and they occur in floodplain deposits of alluvial
fan and meandering river settings. Thus, we conclude that dinosaurs
inhabited volcanically influenced, alluvial fan, fluvial plain, and
lake margins on the Korean Peninsula throughout the Cretaceous under a
semi-arid climate with strong seasonality. The rarer occurrence of
dinosaur tracks in older Cretaceous deposits in some basins might be
attributed to the limited exposures of lake-margin deposits. It is
inferred that the presence of large lakes as water sources, rich
vegetation of gymnosperm trees as food, and semi-arid paleoclimatic
conditions formed a general landscape and environmental setting
favorable for dinosaurs and their preservation in the Cretaceous
deposits of South Korea.


==


Martin G. Lockley, Jong-Deock Lim, Jeong Yul Kim, Kyung Soo Kim, Min
Huhe & Koo-Geun Hwang (2012)
Tracking Korea's Early Birds: A Review of Cretaceous Avian Ichnology
and Its Implications for Evolution and Behavior.
Ichnos 19 (1-2): 17-27
DOI:10.1080/10420940.2012.660409
http://www.tandfonline.com/doi/abs/10.1080/10420940.2012.660409


Bird tracks are abundant and ubiquitous in many Cretaceous formations
in Korea. To date, in order of discovery and description, the
following six ichnogenera have been reported: Koreanaornis,
Jindongornipes, Uhangrichnus, Hwangsanipes, Ignotornis, Goseongornipes
and ?Aquatilavipes. As more bird tracks are discovered it has become
possible to amend descriptions of existing ichnotaxa to better
understand track morphology (and ichnotaxonomic relationships),
trackway patterns and associated feeding traces and gain further
insight into the behavior and ecology. We review and re-evaluate the
most important bird tracksites in Korea, with special reference to
sites not previously fully or adequately described in accessible
English language journals. We pay special attention to material from
the Uhangri Dinosaur Museum, Haenam area, and the Gyeongsangnamdo
Institute of Science Education, Gajin area, presenting revised
descriptions, illustrations and information on Uhangrichnus and
Goseongornipes.


==


Jeong Yul Kim, Martin G. Lockley, Seung Jo Seo, Kyung Soo Kim, Sam
Hyang Kim & Kwang Seok Baek (2012)
A Paradise of Mesozoic Birds: The World's Richest and Most Diverse
Cretaceous Bird Track Assemblage from the Early Cretaceous Haman
Formation of the Gajin Tracksite, Jinju, Korea.
Ichnos 19 (1-2): 28-42
DOI:10.1080/10420940.2012.660414
http://www.tandfonline.com/doi/abs/10.1080/10420940.2012.660414


More than 2,500 well-preserved bird tracks associated with theropod
and sauropod tracks are recorded from a dense assemblage in lacustrine
deposits of the Early Cretaceous Haman Formation of the Gajin area,
Jinju, Korea. These tracks are preserved in the recently constructed
Fossil Heritage Hall at the Gyeongsangnamdo Institute of Science
Education. Bird tracks are attributed to Ignotornis gajinensis
ichnosp. nov., Koreanaornis hamanensis, Goseongornipes markjonesi, and
?Aquatilavipes. Like G. markjonesi, I. gajinensis is a semi-palmate
bird track, similar to Hwangsanipes (ichnofamily Ignotornidae) with a
postero medially directed hallux and characterized by interdigital
angles between digits II and III larger than III and IV. However,
Hwangsanipes is a larger morphotype than Ignotornis with a more
pronounced semipalmate web. I. gajinensis has associated arcuate to
semi-circular, double-grooved, or paired impressions resulting from
spoonbill-like feeding behavior. Similar rare but more linear traces
occur in one Ignotornis specimen from the Cretaceous of Colorado. The
Gajin site represents a record of the world's most-dense assemblage of
bird tracks (up to 600 per m2) at a single locality and provides
striking evidence of the diversity of avian ichnotaxa during the
Cretaceous. The Gajin tracksite provides new insight into the
morphology of four of the eight ichnogenera known from the Cretaceous
of Korea. The Goseongornipes sample is the largest and best-preserved
available. In the case of Ignotornis, feeding traces shed new light on
behavior and paleoecology of the trackmakers, which appear to have
been remarkably convergent with modern shore birds.

===

Min Huh, Martin G. Lockley, Kyung Soo Kim, Jeong Yul Kim & Se-Geon Gwak (2012)
First Report of Aquatilavipes from Korea: New Finds from Cretaceous
Strata in the Yeosu Islands Archipelago.
Ichnos 19 (1-2): 43-49
DOI:10.1080/10420940.2011.632297
http://www.tandfonline.com/doi/abs/10.1080/10420940.2011.632297


Cretaceous bird tracks assigned to the ichnogenera Aquatilavipes and
Koreanaornis are reported for the first time from Sado Island in the
Yeosu Island archipelago, Korea, an area already known for multiple
dinosaur track-bearing horizons. The Koreanaornis tracks are
associated with many small Cochlichnus trails attributed to nematode
worms, on which the birds were likely feeding in a lake shoreline
environment. The Koreanaornis and Aquatilavipes assemblages occur at
different, albeit close, stratigraphic levels. The Aquatilavipes
report is the first from Korea.

==

J. Y. Kim, M. G. Lockley, K. S. Kim, S. J. Seo & J. D. Lim (2012)
Enigmatic Giant Pterosaur Tracks and Associated Ichnofauna from the
Cretaceous of Korea: Implication for the Bipedal Locomotion of
Pterosaurs.
Ichnos 19 (1-2): 50-65
DOI:10.1080/10420940.2011.625779
http://www.tandfonline.com/doi/abs/10.1080/10420940.2011.625779

Enigmatic tracks and dinosaur trackways from lacustrine margin
sediments of the Lower Cretaceous Haman Formation of the southern
coast of Korea represent a new ichnospecies. Trackways with large,
pes-only tracks with lengths up to 39 cm, characterized by elongate,
subtriangular outlines, impressions of four digits and a subangular
heel, are attributed to plantigrade pterodactyloids and assigned to
Haenamichnus gainensis ichnosp. nov. These tracks comprise one of the
largest and longest pterosaur trackways hitherto reported and provide
intriguing new insight into pterosaur locomotory gait and stance,
which has been the subject of a 200-year-long controversy. Associated
sauropod tracks, assigned herein to Brontopodus birdi, reach 70 cm in
length, are medium-gauged, and show outwardly curved digit
impressions. E-W trackway alignments likely indicate shoreline trends
but could possibly suggest behavioral hunting scenarios. Pes-only
pterosaur tracks at this locality are another example of spoor
incorrectly interpreted by creationists as the footprints of humans
that coexisted with dinosaurs during the Cretaceous Period. This
erroneous interpretation is popular in some circles in Korea.

==


Kyung Soo Kim, Martin G. Lockley, Jeong Yul Kim & Seong Jo Seo (2012)
The Smallest Dinosaur Tracks in the World: Occurrences and
Significance of Minisauripus from East Asia.
Ichnos 19 (1-2): 66-74
DOI:10.1080/10420940.2012.664052
http://www.tandfonline.com/doi/abs/10.1080/10420940.2012.664052


We review the status of the distinctive ichnogenus Minisauripus based
on more than 80 well-preserved tracks comprising a minimum of 50
trackways from two localities in China and five in Korea. The tracks,
attributed to theropod dinosaurs, have been assigned to two
ichnospecies, M. chuanzhuensis and M. zhenshounani, based on Chinese
specimens. Until recently, the known range of foot lengths was 1.5–6.0
cm, indicating a diminutive track-making species. However, newly
discovered Minisauripus tracks from the Haman Formation in the
Changseon region of Korea are as short as 1.0 cm. Most remarkably, a
few, provisionally also labeled cf. Minisauripus, are reported as
large as 16–20 cm, potentially adding unprecedented new data to the
previous record. The larger tracks suggest that all the small tracks
pertain to juveniles and not a small, distinct species as previously
inferred. Tracks with foot lengths of only 1 cm suggest that
individuals hatched from very small eggs. The fact that such tracks
are abundant in fine-grained, lake-margin facies argues for the
importance of suitable preservational conditions in recording the
activity of small trackmakers. Thus, inferences about dinosaur
population structure, growth rates, and other biological and
ecological phenomena, based on the absence of small dinosaur tracks,
should be made with caution.


===


Jeong Yul Kim, Martin G. Lockley, Jeong Ok Wooa & Sam Hyang Kim (2012)
Unusual Didactyl Traces from the Jinju Formation (Early Cretaceous,
South Korea) Indicate a New Ichnospecies of Dromaeosauripus..
Ichnos 19 (1-2): 75-83
DOI:10.1080/10420940.2012.664054
http://www.tandfonline.com/doi/abs/10.1080/10420940.2012.664054


New didactyl dinosaur tracks from the fine-grained sandstone of the
Early Cretaceous Jinju Formation, Namhae area, Korea, are herein
described as Dromaeosauripus jinjuensis ichnosp. nov. A trackway about
4.3 m long is composed of 12 consecutive didactyl traces. The tracks
average about 9.3 cm long and 6.8 cm wide. Pace, stride, and pace
angulation are 40 cm, 80 cm, and 175°, respectively. D. jinjuensis is
a small didactyl track characterized by slender digit impressions,
very narrow divarication angle between digits III and IV, digit III
slightly longer than IV, and sharp claw impressions. D. jinjuensis
measurements differ significantly from D. hamanensis in length (only
60% of the latter), width (81%), length/width ratio (0.72), and digit
thickness (55%). The didactyl tracks are tentatively interpreted to be
formed by a small dromaeosaurid walking bipedally on a lake margin. D.
jinjuensis represents the oldest theropod dinosaur tracks described in
the Cretaceous of Korea and the second ichnospecies of
Dromaeosauripus. It suggests more diversity and wider stratigraphic
and paleogeographic distribution of dromaeosaurids. The track
morphology may also indicate a more digitigrade gait.

===


Jeong Yul Kim & Martin G. Lockley (2012)
New Sauropod Tracks (Brontopodus pentadactylus ichnosp. nov.) from the
Early Cretaceous Haman Formation of Jinju Area, Korea: Implications
for Sauropods Manus Morphology.
Ichnos 19 (1-2): 84-92
DOI:10.1080/10420940.2012.664056
http://www.tandfonline.com/doi/abs/10.1080/10420940.2012.664056

New sauropod tracks are described herein as Brontopodus pentadactylus
ichnosp. nov. from the Early Cretaceous Haman Formation of Jinju area,
Korea. B. pentadactylus is characterized by a medium gauged trackway
with wide pentadactyl manus tracks revealing hitherto unreported
morphology. Thus, B. pentadactylus provides new insight into the
morphology of the fleshed-out manus of sauropods showing that, unlike
most semi-circular manus tracks that lack discrete digit traces, some
indicate trackmakers with clearly differentiated, well-defined, and
very wide manus digits. Manus tracks sometimes appear as tridactyl
impressions that appear outwardly rotated at right angles to the
midline of the trackway. This track morphology appears to reflect
greater weight distribution on the outer, postero-lateral part of the
manus. The pes is elongate, pentadactyl, outwardly rotated, and
typical of Brontopodus. The manus pes heteropody ratio is about 1:2.
These sauropod tracks are associated with thousands of bird footprints
in a lakeshore paleoenvironment.

==

Martin G. Lockley, Min Huh & Bo Sung Kim (2012)
Ornithopodichnus and Pes-Only Sauropod Trackways from the Hwasun
Tracksite, Cretaceous of Korea.
Ichnos 19 (1-2): 93-100
DOI:10.1080/10420940.2011.625726
http://www.tandfonline.com/doi/abs/10.1080/10420940.2011.625726

Trackways of small (foot length 12–15 cm) robust ornithopods are
relatively uncommon in the Cretaceous, where most tracks attributed to
iguanodontids and hadrosaurs range in size from 20–80 cm. The Hwasun
site, previously noted for its abundant theropod trackways, also
reveals one horizon (L2) with at least six parallel trackways of small
blunt-toed ornithopods with wide tracks, short steps and typical
inward rotation of the pes. The site also reveals a second horizon
(L4) which yields a single clear trackway of a much larger blunt-toed
ornithopod. Although allometric trends in tridactyl track assemblages
tend to show increased trackway width and reduced anterior projection
of digit III (reduced mesaxonic emphasis) with increasing size, the
small Hwasun ornithopods reveal unusually wide tracks with reduced
mesaxony. The tracks are herein assigned to the ichnogenus
Ornithopodichnus. A map of previously unmapped Level 4 is presented
showing the context of the large ornithopod tracks on the same surface
as an unusual pes-only trackway with distinctive claw traces and
sediment rims. This surface also reveals isolated sauropod manus
tracks and various underprints.

===


Jong-Deock Lim, Martin G. Lockley & Dal-Yong Kong (2012)
The Trackway of a Quadrupedal Ornithopod from the Jindong Formation
(Cretaceous) of Korea.
Ichnos 19 (1-2): 101-104
DOI:10.1080/10420940.2012.664059
http://www.tandfonline.com/doi/abs/10.1080/10420940.2012.664059


We report the first occurrence of the trackway of a quadrupedal
ornithopod from the Jindong Formation (Late Aptian) of Korea. Although
trackways of ornithopods are abundant in the Cretaceous of Korea,
especially in the Jindong Formation, trackways of a quadrupedal
trackmaker have never been reported from Korea. Moreover, the manus
shows an unusual morphology with three subcircular indentations
arranged in an unusual, elongate arc unlike any seen in other
ornithopod ichnospecies. The specimen is clearly different from all
other known Korean ornithopod footprints and is herein named as
Caririchnium kyoungsookimi. To date, Caririchnium is one of only two
ichnogenus names applied with confidence to Lower Cretaceous
ornithopod tracks from Asia.


====

Martin G. Lockley, Min Huh, Se-Geon Gwak, Koo Geun Hwang & In Sung Paik (2012)
Multiple Tracksites with Parallel Trackways from the Cretaceous of the
Yeosu City Area Korea: Implications for Gregarious Behavior in
Ornithopod and Sauropod Dinosaurs.
Ichnos 19 (1-2): 105-114
DOI:10.1080/10420940.2011.625793
http://www.tandfonline.com/doi/abs/10.1080/10420940.2011.625793


At least six sites with multiple parallel ornithopod trackways and one
site with three parallel sauropod trackways have been mapped in the
track-rich Cretaceous sequence on Sado and Chudo islands, Yeosu City
area, South Korea. A preliminary study of the stratigraphic context of
these tracks indicates that they were made by gregarious subadult or
adult dinosaurs that frequented lake basin settings subject to a
cyclic depositional regime and periodic ash fall. Bird and theropod
dinosaur tracks also occur in the sequence. Mapped sites reveal
between 4 and 14 regularly spaced, ornithopod trackways suggestive of
herding behavior. One site reveals an 84 m-long trackway, the longest
on record for an ornithopod. Only one site reveals parallel sauropod
trackways indicating three animals of equal size traveling eastwards
with an inter-trackway spacing of about 2.25–2.5 m. The footprints
show well preserved pes claw impressions, slightly wide gauge and
large manus/pes ratios (low heteropody). The sedimentological and
ichnofaunal sequences share some similarities with the famous Jindong
successions 50 km to the east, but they also differ significantly in
age and ichnofaunal composition.