Ornithopod footprints with metatarsal traces from Lower Cretaceous of Spain + anomalous carbon isotope values in Cretaceous dinosaur bioapatite (free pdfs)
83 views
Skip to first unread message
Ben Creisler
Jun 26, 2026, 7:56:42 PM (6 days ago) Jun 26
to DinosaurMa...@googlegroups.com
Ben Creisler
Ben Egan, Thomas M. Cullen, Maria I. Velez, Scott M. Rosendahl, Seyed Hesam-Aldin Samaei, Jinkai Xue & Ryan C. McKellar (2026)
13C enrichment within Cretaceous amber as an alternate C3 plant proxy to investigate anomalous carbon isotope values observed within Cretaceous food webs
Cretaceous Research 106446
doi: 10.1016/j.cretres.2026.106446
https://www.sciencedirect.com/science/article/pii/S0195667126001357
Highlights
Unity dinosaur bioapatite is anomalously enriched in 13C.
13C enrichment in Unity ambers explain some of the 13C enrichment in dinosaurs.
Other factors must be contributing to anomalous 13C enrichment in dinosaurs.
Abstract
Stable carbon isotope analysis of animal tissues has commonly been used in trophic studies to determine dietary preference. Bioapatite from Late Cretaceous animals has consistently demonstrated anomalously enriched δ13C values for organisms living in a predominantly C3 plant-dominated ecosystem. The origin of such enrichment is poorly understood. Initially thought to be only occurring within Dinosauria, 13C enrichment is now observed in a wide range of Cretaceous vertebrates and thought to be a result of an unknown ecosystem-wide shift in isotopic baseline. Several factors have been suggested as potential contributors to the observed enrichment, such as diagenesis, dietary preferences, aquatic-terrestrial resource exchange, and/or environmental pressures resulting in 13C enrichment in C3 plants. This study focuses on improving estimates of the average δ13C values for Cretaceous C3 plants by using amber stable isotope geochemistry. δ13C values were measured from ambers within a Dinosaur Park Formation bonebed near Unity, Saskatchewan. Our results suggest that the average δ13C value for C3 plants were +1.4‰ more enriched at Unity than previously described in studies using ambient organic carbon. In addition to reporting an enriched δ13C amber baseline, bioapatite from the site is notably enriched compared to amber (+19.6‰, σ = 1.41 for ceratopsians and +20.3‰, σ = 1.59 for hadrosaurs). While other factors could possibly be contributing to the carbon isotope enrichment seen in Cretaceous animals, the 13C enrichment of C3 plants suggests atmospheric factors and/or regional environmental inputs played a large role in the recently defined positive Carbon Isotope Anomaly in Cretaceous vertebrate enamel.
Recent papers:
Ricardo Ochoa Martínez, María José Ochoa Martínez, Adrián Páramo Blázquez, Isabel Ibáñez Lavega, Arturo Fernández Ortega & Félix Pérez-Lorente (2026)
Huellas ornitópodas con marca de metatarso en el Cretácico Inferior de la Cuenca de Cameros (Enciso, La Rioja, España) /
Ornithopod footprints with metatarsal traces in the Lower Cretaceous of the Cameros Basin (Enciso, La Rioja, Spain)
GEOGACETA 79: 83-86 (in Spanish)
Free pdf:
https://sge.usal.es/archivos/geogacetas/geo79/geo79_p_83_86.pdf
In this paper, two bipedal ornithopod trackways attributed to Caririchnium with additional metatarsal marks are described. The morphology of the footprints is congruent with a metatarsal inclined position, and their trace is due to the depth at which the foot was sunk in the mud. Metatarsal marks are not abundant in ornithopod footprints (sensu Romero Molina et al., 2003)., Ornithopods footprints with metatarsal marks have only been found in two sites among the more than 9,000 dinosaur footprints studied in La Rioja.
Free pdf:
Ricardo Ochoa Martínez, María José Ochoa Martínez, Adrián Páramo Blázquez, Isabel Ibáñez Lavega, Arturo Fernández Ortega & Félix Pérez-Lorente (2026)
Huellas ornitópodas con marca de metatarso en el Cretácico Inferior de la Cuenca de Cameros (Enciso, La Rioja, España) /
Ornithopod footprints with metatarsal traces in the Lower Cretaceous of the Cameros Basin (Enciso, La Rioja, Spain)
GEOGACETA 79: 83-86 (in Spanish)
Free pdf:
https://sge.usal.es/archivos/geogacetas/geo79/geo79_p_83_86.pdf
In this paper, two bipedal ornithopod trackways attributed to Caririchnium with additional metatarsal marks are described. The morphology of the footprints is congruent with a metatarsal inclined position, and their trace is due to the depth at which the foot was sunk in the mud. Metatarsal marks are not abundant in ornithopod footprints (sensu Romero Molina et al., 2003)., Ornithopods footprints with metatarsal marks have only been found in two sites among the more than 9,000 dinosaur footprints studied in La Rioja.
====
Free pdf:
Ben Egan, Thomas M. Cullen, Maria I. Velez, Scott M. Rosendahl, Seyed Hesam-Aldin Samaei, Jinkai Xue & Ryan C. McKellar (2026)
13C enrichment within Cretaceous amber as an alternate C3 plant proxy to investigate anomalous carbon isotope values observed within Cretaceous food webs
Cretaceous Research 106446
doi: 10.1016/j.cretres.2026.106446
https://www.sciencedirect.com/science/article/pii/S0195667126001357
Highlights
Unity dinosaur bioapatite is anomalously enriched in 13C.
13C enrichment in Unity ambers explain some of the 13C enrichment in dinosaurs.
Other factors must be contributing to anomalous 13C enrichment in dinosaurs.
Abstract
Stable carbon isotope analysis of animal tissues has commonly been used in trophic studies to determine dietary preference. Bioapatite from Late Cretaceous animals has consistently demonstrated anomalously enriched δ13C values for organisms living in a predominantly C3 plant-dominated ecosystem. The origin of such enrichment is poorly understood. Initially thought to be only occurring within Dinosauria, 13C enrichment is now observed in a wide range of Cretaceous vertebrates and thought to be a result of an unknown ecosystem-wide shift in isotopic baseline. Several factors have been suggested as potential contributors to the observed enrichment, such as diagenesis, dietary preferences, aquatic-terrestrial resource exchange, and/or environmental pressures resulting in 13C enrichment in C3 plants. This study focuses on improving estimates of the average δ13C values for Cretaceous C3 plants by using amber stable isotope geochemistry. δ13C values were measured from ambers within a Dinosaur Park Formation bonebed near Unity, Saskatchewan. Our results suggest that the average δ13C value for C3 plants were +1.4‰ more enriched at Unity than previously described in studies using ambient organic carbon. In addition to reporting an enriched δ13C amber baseline, bioapatite from the site is notably enriched compared to amber (+19.6‰, σ = 1.41 for ceratopsians and +20.3‰, σ = 1.59 for hadrosaurs). While other factors could possibly be contributing to the carbon isotope enrichment seen in Cretaceous animals, the 13C enrichment of C3 plants suggests atmospheric factors and/or regional environmental inputs played a large role in the recently defined positive Carbon Isotope Anomaly in Cretaceous vertebrate enamel.
Reply all
Reply to author
Forward
0 new messages