Current
Research
Here are brief summaries of some of the research currently
being undertaken by our research group.
Arctic
trace fossils: This
ongoing research gives startling insight into the
paleoecology of high latitude environments during the
Cretaceous. Fossil trackways produced by large herds of
hadrosaurs indicate that herds composed of individuals
ranging from very young to adult remained in high latitudes
year round. Trace fossils produced by beetles and other
arthropods confirm that temperatures were warm throughout
the year, so there would be vegetation to support large
herbivores even in the winter. This project is part of a
joint research effort in conjunction with the Museum of
Nature and Science and the Hokkaido University Museum.
Research is on going.
Researchers: Hasiotis, Fiorillo, Kobayashi
Biogenic structures of
continental organisms: The aim of this study is to compare the
burrows made by modern continental organisms to fossil
burrows found in rocks interpreted as continental
environments. Neoichnological experiments with
sand-swimming snakes and amphisbaenians were conducted to
attribute unidentified trace fossils with known organisms
and to infer paleoecologic settings from the architectural
and surficial morphology of their burrows. Other burrows
studied from the Permian and the Eocene-Oligocene were
found to be primarily media-controlled, indicating that
only strong climate change can affect soil organisms. These
studies have been linked to other taxonomic, phylogenetic,
and paleobiogeographic studies to better define the fossil
history of the amphisbaenians. Research in such organisms
is on going.
Researchers: Hembree and Hasiotis
Enigmatic sedimentary
structures in the Navajo Sandstone: Cylindtrical structures found in the
Navajo Sandstone were investigated. Architectural
morphology (sinuosity, Y- and T-branching, spiral ramps,
chambers, and bilobate tunnels) and surficial morphology
(scratch marks) indicate that these structures are burrows
produced by mammals or therapsids. The networks made by the
branches also indicate that these structures were made by
social groups of organisms. This research indicates that
mammals much larger than prairie dogs were capable of
living as social organisms within the soil. Research is on
going.
Researchers: Riese, Hasiotis, Odier (deceased)
Ichnologic and
paleoenvironmental analysis of the Morrison
Formation: Our group
currently is conducting several research projects on the
Morrison Formation. The first is an ongoing research
project cataloging the diversity of trace fossils preserved
in the Morrison Formation. The preliminary efforts of this
research are presented in Hasiotis’s 2004 paper,
Reconnaissance of Upper Jurassic Morrison Formation
ichnofossils, which you can find here. The second is on the
taphonomy and paleoenvironment of the Morrison Formation in
the Bighorn Basin of Wyoming. The field area in this study
is highly fossiliferous, containing numerous Camarasaur
bones and Allosaur teeth in a weakly developed paleosol. It
was determined from this evidence that this deposit is the
remains of a scavenging event by several juvenile and few
adult Allosaurs. Further sedimentologic analysis
demonstrates that the area was a poorly drained environment
with high input from volcanic systems. It was determined
that the strongest paleoenvironmental control on this
system was volcanic activity rather than climate change.
The last project is an integrated study of the Morrison
Formation using ichnology, paleopedology, and geochemistry.
A chemostratigraphic profile showing the variation of
organic carbon with paleoclimate will be developed for the
Upper Morrison Formation near Ticaboo, Utah. Research is on
going.
Researchers: Hasiotis, Jennings, and Platt
Ichnology of the
Catskill Formation: The trace fossil assemblage of the Upper
Devonian Catskill Formation of north-central PA was
investigated. The trace fossil associations of the
different paleoenvironments (point bar, proximal and distal
floodplains) recorded there will be assessed. The main
objective of this research is to determine the role of soil
biota in soil formation in the early evolution of
terrestrial ecosystems. This linkage between tracemaking
biota and soil formation is important because soil biota
today is the driving force in the nutrient cycling system,
and that they have been demonstrated to be ecosystem
engineers that modulate the flow and recycling of
nutrients. Research is on going.
Researchers: Jones and Hasiotis
Ichnology of Mazon
Creek: Trace fossils
from the Mazon Creek area of Illinois were studied.
Specimens from the KU museum and the Field Museum in
Chicago were cataloged and photographed. For many of the
specimens, their ichnotaxonomy was reassessed. When the
catalog is completed, ichnofacies will be erected to
describe the trace fossil distribution. The
paleoenvironment of the Mazon Creek deposit will be
inferred from the ichnofacies. Research is on going.
Researchers: Lobue and Hasiotis
Ichnology of the
Willwood Formation: This comprehensive study of the trace
fossils found in the Willwood Formation in the Bighorn
Basin of Northern Wyoming, was used to reconstruct the
paleoecology and paleoclimate of the region during the
Paleocene-Eocene Thermal Maximum (PETM). The PETM was a
rapid, high magnitude warming event that persisted for only
tens of thousands of years, but it had a tremendous effect
on the environment in the Bighorn Basin. The trace fossil
assemblages found during PETM demonstrate that transient
warming created dry conditions and well-drained soils,
whereas the soils after the PETM were poorly drained as a
result of wetter climatic conditions. Trace fossils overall
were larger during the PETM, suggesting that climate has a
strong effect on the body size of burrowing arthropods.
This research also resulted in the erection of a new
ichnogenus and ichnospecies, Naktodemasis bowni, which is a
type of adhesive meniscate burrow found in well-drained
soils. Research is on going as numerous trace fossils have
yet to be taxonomically assigned and more materials and new
relationships between trace fossils and paleosols are being
found.
Researchers: Hasiotis, Smith, Kraus
Megafaunal
ichnology: Elephants
were studied as modern tracemaking analogs for sauropod
dinosaurs. The goal of this research is to determine the
effect of soil moisture on the preservation of megafaunal
footprints, in order to interpret moisture levels of
ancient soils from fossil megafunal tracks. A direct
correlation between track volume and soil moisture was
determined from the studies with elephants, which serves as
an independent estimator of ancient moisture levels.
Research is on going, and new opportunities are possible
with other megaherbivores.
Researchers: Platt and Hasiotis
Mesozoic avian
ichnology: Bird
behaviors were interpreted from a Mesozoic track site.
Takeoff behavior was interpreted from trackways consisting
of paired tracks prior to trackway termination. Foraging
behaviors were also interpreted based on similarity to
modern shorebird trackways. The presence of these behaviors
confirms fossil evidence that some groups of early birds
occupied similar niches to those of modern birds. Research
is on going.
Researchers: Falk, Hasiotis, Martin
Neoichnology of cicada
nymphs and beetle grubs: Cicada nymphs and beetle grubs were
placed into experimental enclosures and observed in order
to explain the morphology of their traces. It was observed
that these nymphs and grubs were able to make adhesive
meniscate burrows in well-drained media without ingesting
sediment. Grubs and nymphs moved through the sediment by
excavating an empty cell around their bodies, then moved
the cell through the enclosure by scraping sediment from
the front of the cell, grasping sediment in their limbs
while somersaulting, then packing the sediment behind them
on the back end of the cell. Burrows produced in enclosures
of layered, colored sand appeared as long bands of
crescent-shaped material of alternating color. This
research falsifies the previous hypothesis that
sediment-ingesting organisms produce this style of burrow
and are restricted to marine settings and aquatic or
saturated continental environments. Research is on going as
there is a vast opportunity to study a wide variety of
insects, arthropods, and other invertebrates that spend
some portion of their lives in soil.
Researchers: Hasiotis, Smith, Counts
Neoichnology of
vinegaroons: This
study documented the tracemaking ability of vinegaroons
(whip scorpions). Vinegaroons are organisms related to
scorpions, except they lack a stinging tail and their first
set of walking limbs are modified into antennae-like
structures. Experiments were performed in nine trials of
varying grain size and moisture settings. Trackways were
found to be preserved better in settings that were dry and
fine-grained, with the preservation potential of trackways
decreasing as the media became coarser and wetter.
Individual tracks were oblong to striate and were arranged
in triangular patterns. It is hoped that this research will
be used to identify fossil vinegaroon trackways, which have
been previously undescribed in the fossil record. Research
in this venue is on going as the trackways and behaviors of
a variety of arthropods have yet to be documented in
detail.
Researchers: Schmerge, Riese, Hasiotis.
Paleoenvironmental
analysis of the White River Formation: The paleoecology and paleoclimate of the
White River Formation near Douglas, Wyoming was
investigated. This formation contains a record of the
Eocene-Oligocene transition, a time of significant global
cooling. This event was interpreted from the field area
based on paleoenvironmental analysis of paleosols, which
indicated that forest cover receded during the Oligocene.
Stable isotope analysis of carbonate from these rocks
confirms that paleotemperatures decreased during the
transition as well. These paleoclimate records will be
compared to body mass approximations of mammals from those
times to evaluate the effect of climate change on mammalian
body mass. Research is on going.
Researchers: Schmerge, Hasiotis, Martin