James R. Thomka
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View article: Paleobiological and Taphonomic Implications of Atypical Diploporitan Echinoderm Thecal Attachment Structures—Two Illustrations from the Middle Silurian (Wenlock: Sheinwoodian) of Southern Indiana
Paleobiological and Taphonomic Implications of Atypical Diploporitan Echinoderm Thecal Attachment Structures—Two Illustrations from the Middle Silurian (Wenlock: Sheinwoodian) of Southern Indiana Open
The holocystitid diploporitan Paulicystis occurs within the middle Silurian (Wenlock: Sheinwoodian) Massie Formation of southeastern Indiana, where it utilized its large thecal base as an attachment structure. In softgrounds, Paulicystis t…
View article: Ichnotaxonomic Revisions to Trace Fossils in Echinoderm Substrata from the Silurian Massie Formation of Southern Indiana
Ichnotaxonomic Revisions to Trace Fossils in Echinoderm Substrata from the Silurian Massie Formation of Southern Indiana Open
Several ichnofossils emplaced within stalked echinoderm substrata have been described and figured from the middle Silurian Massie Formation of Ripley County, southeastern Indiana. Reconsideration and reinvestigation of figured and studied …
View article: Silurian Diploporitans as Substrata:
Silurian Diploporitans as Substrata: Open
The middle Silurian Massie Formation of southeastern Indiana contains a rich stalked echinoderm fauna, of which diploporitan “cystoids” are a significant component. A small number of diploporitan thecae are encrusted by the dendritic radic…
View article: Noteworthy Taphonomic Attributes of a Nautiloid Cephalopod from the Middle Silurian (Wenlock) Massie Formation of Southern Indiana
Noteworthy Taphonomic Attributes of a Nautiloid Cephalopod from the Middle Silurian (Wenlock) Massie Formation of Southern Indiana Open
A specimen of the nautiloid cephalopod Dawsonoceras annulatum from the middle Silurian (Wenlock) Massie Formation of southeastern Indiana, USA, is herein described because of its suite of uncommon taphonomic characteristics. Three notewort…
View article: Improving our Understanding of Evolutionary Paleoecology: A Celebration of the Work and Career of Tomasz K. Baumiller
Improving our Understanding of Evolutionary Paleoecology: A Celebration of the Work and Career of Tomasz K. Baumiller Open
Peer Reviewed
View article: Crinoid Anal Sac Spines with Multiple Planes of Regeneration: Predation-Generated Features in the Upper Pennsylvanian of Eastern Ohio, USA
Crinoid Anal Sac Spines with Multiple Planes of Regeneration: Predation-Generated Features in the Upper Pennsylvanian of Eastern Ohio, USA Open
Peer Reviewed
View article: Crinoid encrustation of holocystitid diploporitan echinoderms: strongly asymmetrical Silurian dendritic attachment structures with palaeobiological implications
Crinoid encrustation of holocystitid diploporitan echinoderms: strongly asymmetrical Silurian dendritic attachment structures with palaeobiological implications Open
Articulated thecae of the holocystitid diploporitan echinoderm Holocystites scutellatus from the middle Silurian (Wenlock: Sheinwoodian) Massie Formation of southeastern Indiana, USA, are encrusted by distinctive structures belonging to an…
View article: Paleoecological Significance of a Pre-Mortem Crinoid-Coral Interaction from the Silurian of Southeastern Indiana
Paleoecological Significance of a Pre-Mortem Crinoid-Coral Interaction from the Silurian of Southeastern Indiana Open
A noteworthy specimen recording a syn vivo interaction between a stalked echinoderm and a tabulate coral is described herein from the middle Silurian (Wenlock: Sheinwoodian) Massie Formation of Ripley County, southeastern Indiana. Part of …
View article: Sequential, multi-taxon encrustation of an orthoceratid cephalopod by stalked blastozoan echinoderms in the middle Silurian (Wenlock Series) of southeastern Indiana, USA
Sequential, multi-taxon encrustation of an orthoceratid cephalopod by stalked blastozoan echinoderms in the middle Silurian (Wenlock Series) of southeastern Indiana, USA Open
Encrustation of bioclasts by stalked echinoderms (pelma tozoans) in softsubstrate paleoenvironments is a well known and frequently documented phenomenon in Silurian marine strata (e.g., Brett 1984Brett , 1991)).Cephalopods are occasionally…
View article: Peer Review #2 of "Uncovering the hidden diversity of Mississippian crinoids (Crinoidea, Echinodermata) from Poland (v0.1)"
Peer Review #2 of "Uncovering the hidden diversity of Mississippian crinoids (Crinoidea, Echinodermata) from Poland (v0.1)" Open
Partial crinoid crowns and aboral cups are reported from the Mississippian of Poland for the first time.Most specimens are partially disarticulated or isolated plates, which prevent identification to genus and species, but regardless these…
View article: Taphonomic Implications of a Crinoid from Echinoderm-Poor Lithofacies in the Upper Ordovician (Katian: Cincinnatian) of Northern Kentucky
Taphonomic Implications of a Crinoid from Echinoderm-Poor Lithofacies in the Upper Ordovician (Katian: Cincinnatian) of Northern Kentucky Open
Crinoids (Phylum Echinodermata) represent major components of fossil assemblages in the type Cincinnatian (Upper Ordovician: Katian) of the greater Cincinnati Arch region. However, certain shallow marine lithofacies are characterized by a …
View article: Interaction between dendritic radix structures of pelmatozoan echinoderms on a hardground in the middle Silurian (Wenlock) of southeastern Indiana, USA
Interaction between dendritic radix structures of pelmatozoan echinoderms on a hardground in the middle Silurian (Wenlock) of southeastern Indiana, USA Open
View article: A noteworthy accumulation of disparid crinoids from the type Cincinnatian (Upper Ordovician) of southwestern Ohio, USA: implications for the palaeoecology and taphonomy of crinoid “logjam” assemblages
A noteworthy accumulation of disparid crinoids from the type Cincinnatian (Upper Ordovician) of southwestern Ohio, USA: implications for the palaeoecology and taphonomy of crinoid “logjam” assemblages Open
View article: Notes on Additional Material Associated with the Type Specimens of Diphuicrinus ohioensis (Echinodermata: Crinoidea) from the Middle Pennsylvanian of Southeastern Ohio
Notes on Additional Material Associated with the Type Specimens of Diphuicrinus ohioensis (Echinodermata: Crinoidea) from the Middle Pennsylvanian of Southeastern Ohio Open
The cladid crinoid Diphuicrinus ohioensis Burke, 1976, was originally described from shallow marine facies of the Middle Pennsylvanian Putnam Hill Limestone of southeastern Ohio. One of the type localities for this taxon is an abandoned qu…
View article: The role of preservation on the quantification of morphology and patterns of disparity within Paleozoic echinoderms
The role of preservation on the quantification of morphology and patterns of disparity within Paleozoic echinoderms Open
The loss of information resulting from taphonomic degradation could represent a significant bias in the study of morphological diversity. This potential bias is even more concerning given the uneven effect of taphonomy across taxonomic gro…
View article: Sequence boundaries and chronostratigraphic gaps in the Llandovery of Ohio and Kentucky: The record of early Silurian paleoceanographic events in east-central North America
Sequence boundaries and chronostratigraphic gaps in the Llandovery of Ohio and Kentucky: The record of early Silurian paleoceanographic events in east-central North America Open
New and published data are integrated herein to resolve the age and stratigraphic relationships for problematic strata of the Aeronian and Telychian (Llandovery; Silurian) in Ohio and Kentucky (USA). At least two major depositional sequenc…
View article: Sequence stratigraphic model for repeated “butter shale” Lagerstätten in the Ordovician (Katian) of the Cincinnati, Ohio region, USA
Sequence stratigraphic model for repeated “butter shale” Lagerstätten in the Ordovician (Katian) of the Cincinnati, Ohio region, USA Open
The “butter shale” Lagerstätten of the Cincinnati Arch have produced an abundance of articulated trilobites, along with assorted bivalves and cephalopods. These bluish gray shales are rich in clay, poorly calcified, and show vague internal…
View article: Calibrating water depths of Ordovician communities: lithological and ecological controls on depositional gradients in Upper Ordovician strata of southern Ohio and north-central Kentucky, USA; pp. 19–23
Calibrating water depths of Ordovician communities: lithological and ecological controls on depositional gradients in Upper Ordovician strata of southern Ohio and north-central Kentucky, USA; pp. 19–23 Open
Limestone and shale facies of the Upper Ordovician Grant Lake Formation (Katian: Cincinnatian, Maysvillian) are well exposed in the Cincinnati Arch region of southern Ohio and north-central Kentucky, USA. These rocks record a gradual chang…
View article: Dynamic linkages between stratigraphy, climate, oceanography, and biotic events in the middle Silurian of eastern Laurentia
Dynamic linkages between stratigraphy, climate, oceanography, and biotic events in the middle Silurian of eastern Laurentia Open