{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/32503"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/32503","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Quantitative Taphonomy of a Triassic Reptile: Tanytrachelos ahynis from the Cow Branch Formation, Dan River Basin, Solite Quarry, Virginia","abstract":"The Virginia Solite Quarry assemblage of Tanytrachelos ahynis, with its exceptionally abundant and uniquely preserved specimens, offers an opportunity to quantify multiple aspects of vertebrate taphonomy. The presence or absence of 128 skeletal elements (i.e., bones) as well as the presence or absence of 136 skeletal variables (i.e., morphometric dimensions) were recorded for 100 specimens collected from two distinct layers within the quarry (lake cycles 2 and 16). Anatomical specimen completeness (or the percent of bones/variables present in a specimen) is low (the median specimen preserves 14.5% of bones and 11.8% of measured variables) in spite of protection from high energy currents, predators, and scavengers afforded by anoxic bottom waters. Specimen size, as approximated by femur length, does not significantly impact specimen completeness. Also, post-exhumation weathering, duration of exposure before burial, and morphotype groupings do not appear to have significantly affected anatomical specimen completeness or articulation. Presence or absence of the enigmatic heterotopic bones represents a true biological signal as indicated by the lack of significant difference in anatomical specimen completeness between the two morphotypes as well as qualitative taphonomic evidence. When anatomical specimen completeness has been corrected for post-depositional faulting, lake cycles 2 and 16 differ from one another significantly in terms of articulation and anatomical completeness of specimens. Specimens with soft-bodied preservation are significantly more articulated, but not significantly more complete, than specimens without preserved soft tissues. Preservation frequency of bones/variables (or the percent of specimens in which a bone/variable is present) varies greatly, but is generally low (an average skeletal element is present in 19% of specimens and an average variable can be measured in 12% of specimens), with significant preferential removal of smaller skeletal elements. Hind limbs, specifically femora, are most commonly preserved. Low anatomical specimen completeness and positive correlation between bone size and frequency of preservation both indicate specimen disturbance by minor hydraulic currents. These taphonomic patterns suggest a moderate-depth depositional environment (slightly shallower than previously proposed).","abstract_html":"The Virginia Solite Quarry assemblage of Tanytrachelos ahynis, with its exceptionally abundant and uniquely preserved specimens, offers an opportunity to quantify multiple aspects of vertebrate taphonomy. The presence or absence of 128 skeletal elements (i.e., bones) as well as the presence or absence of 136 skeletal variables (i.e., morphometric dimensions) were recorded for 100 specimens collected from two distinct layers within the quarry (lake cycles 2 and 16). Anatomical specimen completeness (or the percent of bones/variables present in a specimen) is low (the median specimen preserves 14.5% of bones and 11.8% of measured variables) in spite of protection from high energy currents, predators, and scavengers afforded by anoxic bottom waters. Specimen size, as approximated by femur length, does not significantly impact specimen completeness. Also, post-exhumation weathering, duration of exposure before burial, and morphotype groupings do not appear to have significantly affected anatomical specimen completeness or articulation. Presence or absence of the enigmatic heterotopic bones represents a true biological signal as indicated by the lack of significant difference in anatomical specimen completeness between the two morphotypes as well as qualitative taphonomic evidence. When anatomical specimen completeness has been corrected for post-depositional faulting, lake cycles 2 and 16 differ from one another significantly in terms of articulation and anatomical completeness of specimens. Specimens with soft-bodied preservation are significantly more articulated, but not significantly more complete, than specimens without preserved soft tissues. Preservation frequency of bones/variables (or the percent of specimens in which a bone/variable is present) varies greatly, but is generally low (an average skeletal element is present in 19% of specimens and an average variable can be measured in 12% of specimens), with significant preferential removal of smaller skeletal elements. Hind limbs, specifically femora, are most commonly preserved. Low anatomical specimen completeness and positive correlation between bone size and frequency of preservation both indicate specimen disturbance by minor hydraulic currents. These taphonomic patterns suggest a moderate-depth depositional environment (slightly shallower than previously proposed).","abstract_has_math":false,"creators":["Casey, Michelle M."],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Geosciences","degree_department":"Geosciences","school":null,"contributors":[],"advisors":[],"committee_chairs":["Kowalewski, Michal"],"committee_members":["Fraser, Nicholas C.","Xiao, Shuhai"],"year":2005,"date_issued":"2005-04-27","date_published":"2005-04-27","updated_at":"2026-07-22T22:18:44Z","subjects":["Lacustrine","Newark Supergroup","Lagerstatten","Depositional Environment"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05102005-200657"],"render_values":[{"text":"etd-05102005-200657","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/32503","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Kowalewski, Michal"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Fraser, Nicholas C.","Xiao, Shuhai"]},{"key":"dc:contributor.department","label":"Department","values":["Geosciences"]},{"key":"dc:creator","label":"Author","values":["Casey, Michelle M."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:36:02Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:36:02Z","2006-05-18"]},{"key":"dc:date.issued","label":"Date","values":["2005-04-27"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Geosciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Lacustrine","Newark Supergroup","Lagerstatten","Depositional Environment"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05102005-200657"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/32503"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The Virginia Solite Quarry assemblage of Tanytrachelos ahynis, with its exceptionally abundant and uniquely preserved specimens, offers an opportunity to quantify multiple aspects of vertebrate taphonomy. The presence or absence of 128 skeletal elements (i.e., bones) as well as the presence or absence of 136 skeletal variables (i.e., morphometric dimensions) were recorded for 100 specimens collected from two distinct layers within the quarry (lake cycles 2 and 16). Anatomical specimen completeness (or the percent of bones/variables present in a specimen) is low (the median specimen preserves 14.5% of bones and 11.8% of measured variables) in spite of protection from high energy currents, predators, and scavengers afforded by anoxic bottom waters. Specimen size, as approximated by femur length, does not significantly impact specimen completeness. Also, post-exhumation weathering, duration of exposure before burial, and morphotype groupings do not appear to have significantly affected anatomical specimen completeness or articulation. Presence or absence of the enigmatic heterotopic bones represents a true biological signal as indicated by the lack of significant difference in anatomical specimen completeness between the two morphotypes as well as qualitative taphonomic evidence. When anatomical specimen completeness has been corrected for post-depositional faulting, lake cycles 2 and 16 differ from one another significantly in terms of articulation and anatomical completeness of specimens. Specimens with soft-bodied preservation are significantly more articulated, but not significantly more complete, than specimens without preserved soft tissues. Preservation frequency of bones/variables (or the percent of specimens in which a bone/variable is present) varies greatly, but is generally low (an average skeletal element is present in 19% of specimens and an average variable can be measured in 12% of specimens), with significant preferential removal of smaller skeletal elements. Hind limbs, specifically femora, are most commonly preserved. Low anatomical specimen completeness and positive correlation between bone size and frequency of preservation both indicate specimen disturbance by minor hydraulic currents. These taphonomic patterns suggest a moderate-depth depositional environment (slightly shallower than previously proposed)."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Quantitative Taphonomy of a Triassic Reptile: Tanytrachelos ahynis from the Cow Branch Formation, Dan River Basin, Solite Quarry, Virginia"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Kowalewski, Michal"],"dc:contributor.committeemember":["Fraser, Nicholas C.","Xiao, Shuhai"],"dc:contributor.department":["Geosciences"],"dc:creator":["Casey, Michelle M."],"dc:date.accessioned":["2014-03-14T20:36:02Z"],"dc:date.available":["2014-03-14T20:36:02Z","2006-05-18"],"dc:date.issued":["2005-04-27"],"dc:description.abstract":["The Virginia Solite Quarry assemblage of Tanytrachelos ahynis, with its exceptionally abundant and uniquely preserved specimens, offers an opportunity to quantify multiple aspects of vertebrate taphonomy. The presence or absence of 128 skeletal elements (i.e., bones) as well as the presence or absence of 136 skeletal variables (i.e., morphometric dimensions) were recorded for 100 specimens collected from two distinct layers within the quarry (lake cycles 2 and 16). Anatomical specimen completeness (or the percent of bones/variables present in a specimen) is low (the median specimen preserves 14.5% of bones and 11.8% of measured variables) in spite of protection from high energy currents, predators, and scavengers afforded by anoxic bottom waters. Specimen size, as approximated by femur length, does not significantly impact specimen completeness. Also, post-exhumation weathering, duration of exposure before burial, and morphotype groupings do not appear to have significantly affected anatomical specimen completeness or articulation. Presence or absence of the enigmatic heterotopic bones represents a true biological signal as indicated by the lack of significant difference in anatomical specimen completeness between the two morphotypes as well as qualitative taphonomic evidence. When anatomical specimen completeness has been corrected for post-depositional faulting, lake cycles 2 and 16 differ from one another significantly in terms of articulation and anatomical completeness of specimens. Specimens with soft-bodied preservation are significantly more articulated, but not significantly more complete, than specimens without preserved soft tissues. Preservation frequency of bones/variables (or the percent of specimens in which a bone/variable is present) varies greatly, but is generally low (an average skeletal element is present in 19% of specimens and an average variable can be measured in 12% of specimens), with significant preferential removal of smaller skeletal elements. Hind limbs, specifically femora, are most commonly preserved. Low anatomical specimen completeness and positive correlation between bone size and frequency of preservation both indicate specimen disturbance by minor hydraulic currents. These taphonomic patterns suggest a moderate-depth depositional environment (slightly shallower than previously proposed)."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-05102005-200657"],"dc:identifier.uri":["http://hdl.handle.net/10919/32503"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Lacustrine","Newark Supergroup","Lagerstatten","Depositional Environment"],"dc:title":["Quantitative Taphonomy of a Triassic Reptile: Tanytrachelos ahynis from the Cow Branch Formation, Dan River Basin, Solite Quarry, Virginia"],"dc:type":["Thesis"],"thesis:degree_discipline":["Geosciences"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:18:44Z"}