Periodic Reporting for period 2 - JurRad (UNRAVELLING THE JURASSIC RADIATION OF AVEROSTRA (DINOSAURIA, THEROPODA) FROM NEW DATA OF ITS MOST COMPLETE ARGENTINIAN EARLY REPRESENTATIVES AND EXHAUSTIVE PHYLOGENETIC ANALYSES)
Berichtszeitraum: 2024-04-13 bis 2025-04-12
The Marie S. Curie Actions Project “JurRad” focuses on the evolution of the major group of theropod dinosaurs: Averostra. However, despite being one of the most studied groups, it is also one of the most debated within theropods due to the unclear phylogenetic interrelationship of its ‘basal’ members and the relationships between their major clades. Averostra radiated explosively from the Early to Late Jurassic (from 182.7-145 million years), with the Pliensbachian-Toarcian extinction event (182 million years ago) probably being one of the major causes for this explosive evolution. The increase in the rate of morphological change that followed the extinction, together with the fragmentary nature of the fossil record of the ‘basal’ members could be the cause of the difficulties in unraveling the interrelationships among Averostra. The main goal of this research is to obtain a robust and synthetic view of the evolutionary drivers of this radiation of Averostra during the Jurassic, to explore when averostrans originated at the latest and unravel the impact of the previous extinction on their radiation and how the different lineages were established in the aftermath. To achieve this goal, it will carry out phylogenetical analyses of this group, the subsequent assessment of the morphological changes within a phylogenetic context in the early evolution of Averostra, and the evaluation of its connection with the Pliensbachian-Toarcian extinction event and consequent radiation of theropods. Moreover, it will be studied in detail the most complete early members of the two main averostran lineages, Eoabelisaurus mefi and Asfaltovenator vialidadi (Early Jurassic species) from the Patagonia of Argentina (Chubut province). These taxa are exceptionally complete and show unique character combinations, which will be essential for unravelling the role of the radiation in the early diversification of Averostra.
The specific objectives of the project are:
Specific Objective 1: To establish a good sampling of basal members of different clades within Averostra, gathering all the data available about Averostra taxa. Related to Work Package 1: Gathering of the taxa information and osteological data of Averostra taxa in order to have a good sampling of basal members of Averostra.
Specific Objective 2: To perform an exhaustive and detailed osteological description of two of the most complete and representative taxa from the Jurassic Cañadón Asfalto Formation in order to establish the phylogenetical context of these taxa and test for what the character combination seen in these taxa are key to understand about character distribution and morphological evolution in early averostrans. Related to Work package 2: Describing in-depth the osteology of two averostran taxa from the Cañadon Asfalto Formation.
Specific Objective 3: To produce a phylogenetic tree of Theropoda, focusing on the averostran relationships. Related to Work Package 3: Revision of previous analyses and elaboration of a new matrix of morphological characters in order to perform a heuristic and Bayesian search of phylogenetic trees.
Specific Objective 4: To explore the evolution of osteological traits and the evolutionary history of Averostra, analysing the morphological changes within a phylogenetic context, and, posteriorly, evaluate the likely causes of these changes in the early evolution of Averostra and its connection with the Pliensbachian-Toarcian extinction event and consequent radiation of theropods. Related to WP4: Evaluation of the effects of Pliensbachian-Toarcian extinction event in the radiation of Averostra, focusing specially in the effects of the homoplasy in the phylogenetical results.
The specific objectives of the project are:
Specific Objective 1: To establish a good sampling of basal members of different clades within Averostra, gathering all the data available about Averostra taxa. Related to Work Package 1: Gathering of the taxa information and osteological data of Averostra taxa in order to have a good sampling of basal members of Averostra.
Specific Objective 2: To perform an exhaustive and detailed osteological description of two of the most complete and representative taxa from the Jurassic Cañadón Asfalto Formation in order to establish the phylogenetical context of these taxa and test for what the character combination seen in these taxa are key to understand about character distribution and morphological evolution in early averostrans. Related to Work package 2: Describing in-depth the osteology of two averostran taxa from the Cañadon Asfalto Formation.
Specific Objective 3: To produce a phylogenetic tree of Theropoda, focusing on the averostran relationships. Related to Work Package 3: Revision of previous analyses and elaboration of a new matrix of morphological characters in order to perform a heuristic and Bayesian search of phylogenetic trees.
Specific Objective 4: To explore the evolution of osteological traits and the evolutionary history of Averostra, analysing the morphological changes within a phylogenetic context, and, posteriorly, evaluate the likely causes of these changes in the early evolution of Averostra and its connection with the Pliensbachian-Toarcian extinction event and consequent radiation of theropods. Related to WP4: Evaluation of the effects of Pliensbachian-Toarcian extinction event in the radiation of Averostra, focusing specially in the effects of the homoplasy in the phylogenetical results.
Work Package 1: Compilation of information
-Compilation of relevant information about Averostran theropod dinosaurs and the gathering of all the bibliography and photography of these taxa in the Repository of the LMU
Achievements and outcomes:
✓Deliverable 1.1 (D1.1): Database in the Repository in the cloud networking SYNC-PALMUC system of LMU (Beneficiary).
✓Milestone 1 (M1): Compilation of all bibliography, photography, and data.
Work Package 2: Detailed osteological description of averostrans from the Cañadon Asfalto Formation
-Elaboration of the description of the cranial Eoabelisaurus and Asfaltovenator, photography and Ct-Scan of these skulls, the comparison of these two taxa with other averostra, and the evaluation of the evolutionary pattern of their characters.
-Described the postcranial skeleton of Eoabelisaurus and Asfaltovenator. The obtention of photography and 3D surface scan of them, the comparison of these two taxa with other averostra, and the evaluation of the evolutionary pattern of their characters.
Achievements and outcomes:
✓Deliverable 2.1: Manuscript of the Eoabelisaurus description. Plan to submit in May 2025.
✓Deliverable 2.2: Manuscript of the Asfaltovenator description. In prep.
✓Milestone 2: Detailed osteological description of Eoabelisaurus.
✓Milestones 3: Detailed osteological description of Asfaltovenator.
✓Milestone 4: Comparison with other averostran taxa.
Work Package 3: Exhaustive phylogenetic analysis: elaboration of a new data matrix and Parsimonious and Bayesian analysis
-Evaluation of previous phylogenetic matrices.
-Creation of a new and updated matrix of characters and taxa (60% finished)
-Preliminary parsimonious and Bayesian phylogenetic analysis
Achievements and outcomes:
✓Deliverable 3.1: new matrix of Averostra available in MorphoBank. (60% of characters reviewed, created, and updated).
✓Deliverable 3.2: Manuscript of phylogenetic results. Not achieved.
✓Milestone 5: Revision of all the data sets of previous matrices. Fully achieved in Task 3.1.
✓Milestones 6: Results of the parsimonious phylogenetic analysis. Partly achieved.
✓Milestone 7: Results of the Bayesian phylogenetic analysis. Partly achieved.
Work Package 4: Integration of data and evaluation of the effects of Pliensbachian-Toarcian extinction event
- Analysis of ancestral character states for both taxa in preliminary trees.
- Attend in a course about Macroevolutionary analysis using phylogenies.
- Time-Calibration of the preliminary trees
Achievement and outcomes:
✓ Deliverable 4.1: manuscript of the radiation of Averostra. Not achieved.
✓ Milestones 8: elaboration of a graph of homoplasy distribution. Not achieved.
✓ Milestones 9: elaboration of the time-calibrated trees. Partly achieved.
-Compilation of relevant information about Averostran theropod dinosaurs and the gathering of all the bibliography and photography of these taxa in the Repository of the LMU
Achievements and outcomes:
✓Deliverable 1.1 (D1.1): Database in the Repository in the cloud networking SYNC-PALMUC system of LMU (Beneficiary).
✓Milestone 1 (M1): Compilation of all bibliography, photography, and data.
Work Package 2: Detailed osteological description of averostrans from the Cañadon Asfalto Formation
-Elaboration of the description of the cranial Eoabelisaurus and Asfaltovenator, photography and Ct-Scan of these skulls, the comparison of these two taxa with other averostra, and the evaluation of the evolutionary pattern of their characters.
-Described the postcranial skeleton of Eoabelisaurus and Asfaltovenator. The obtention of photography and 3D surface scan of them, the comparison of these two taxa with other averostra, and the evaluation of the evolutionary pattern of their characters.
Achievements and outcomes:
✓Deliverable 2.1: Manuscript of the Eoabelisaurus description. Plan to submit in May 2025.
✓Deliverable 2.2: Manuscript of the Asfaltovenator description. In prep.
✓Milestone 2: Detailed osteological description of Eoabelisaurus.
✓Milestones 3: Detailed osteological description of Asfaltovenator.
✓Milestone 4: Comparison with other averostran taxa.
Work Package 3: Exhaustive phylogenetic analysis: elaboration of a new data matrix and Parsimonious and Bayesian analysis
-Evaluation of previous phylogenetic matrices.
-Creation of a new and updated matrix of characters and taxa (60% finished)
-Preliminary parsimonious and Bayesian phylogenetic analysis
Achievements and outcomes:
✓Deliverable 3.1: new matrix of Averostra available in MorphoBank. (60% of characters reviewed, created, and updated).
✓Deliverable 3.2: Manuscript of phylogenetic results. Not achieved.
✓Milestone 5: Revision of all the data sets of previous matrices. Fully achieved in Task 3.1.
✓Milestones 6: Results of the parsimonious phylogenetic analysis. Partly achieved.
✓Milestone 7: Results of the Bayesian phylogenetic analysis. Partly achieved.
Work Package 4: Integration of data and evaluation of the effects of Pliensbachian-Toarcian extinction event
- Analysis of ancestral character states for both taxa in preliminary trees.
- Attend in a course about Macroevolutionary analysis using phylogenies.
- Time-Calibration of the preliminary trees
Achievement and outcomes:
✓ Deliverable 4.1: manuscript of the radiation of Averostra. Not achieved.
✓ Milestones 8: elaboration of a graph of homoplasy distribution. Not achieved.
✓ Milestones 9: elaboration of the time-calibrated trees. Partly achieved.
The anatomical description of Eoabelisaurus and Asfaltovenator and preliminary phylogenetic analyses demonstrate:
-Eoabelisaurus possesses a mosaic of features between Ceratosaurus and Abelisaurids, and constitutes an essential taxon to improve the phylogenetic results of Ceratosauria and for understanding the ancestral character reconstruction of this group.
-The stable position of Asfaltovenator in allosauroids and its influence on the changes in the topology of the trees are related to its completeness and its potential to provide pivotal information about the evolution of the clade.
Further research using macroevolutionary analysis with phylogenies will be necessary to unravel the evolutionary history of this group and improve the phylogenetic phylogenies of Averostra.
-Eoabelisaurus possesses a mosaic of features between Ceratosaurus and Abelisaurids, and constitutes an essential taxon to improve the phylogenetic results of Ceratosauria and for understanding the ancestral character reconstruction of this group.
-The stable position of Asfaltovenator in allosauroids and its influence on the changes in the topology of the trees are related to its completeness and its potential to provide pivotal information about the evolution of the clade.
Further research using macroevolutionary analysis with phylogenies will be necessary to unravel the evolutionary history of this group and improve the phylogenetic phylogenies of Averostra.