A new crocodylomorph related ootaxon from the late Maastrichtian of the Southern Pyrenees (Huesca, Spain)

ABSTRACT

Crocodylomorph eggs and eggshells are known as old as the Late Jurassic and are frequent components of most multiootaxic eggshell assemblages. Classified within the oofamily Krokolithidae, thei histo- and ultrastructures are conservative throughout geological time, characterised by inverted-trapezoid-shaped shell units that grow from highly spaced basal knobs and present a diagnostic tabular ultrastructure. Here, we report 327 eggshell fragments from a new fossil site from the Maastrichtian of the Southern Pyrenees, Veracruz 1, and erect a new oogenus and oospecies, Pachykrokolithus excavatum oogen. et oosp. nov. characterised by crocodyloid morphotype and a prominent rugosocavate ornamentation. Eggshells from the slightly older locality of Blasi 2b, previously reported as aff. Krokolithidae, are also assigned to this new ootaxon. Different crocodylomorph taxa coexisted during the Late Cretaceous of the Tremp Basin, hindering the attribution of Pachykrokolithus excavatum oogen. et oosp. nov. to a single clade. Nevertheless, allodaposuchid eusuchians were dominant in this ecosystem, and are the most probable producers of Pachykrokolithus excavatum oogen. et oosp. nov. eggs.

KEYWORDS:

• Crocodylomorpha
• Krokolithidae
• eggshell fragments
• Tremp Basin
• Late Cretaceous

Acknowledgments

This research is supported by the PLEC2021-008203 project, funded by MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR”, the Spanish Ministry of Science and Innovation (project PID2021-122612OB-I00) and by the Government of Aragón-FEDER 2014–2020 Construyendo Europa desde Aragón (Group E18: Aragosaurus: Recursos Geológicos y Paleoambientales) and Fundação para a Ciência e a Tecnologia (grant number PTDC/CTA-PAL/31656/2017 and research unit UIDB/04035/2020; GeoBioTec). Authors would like to acknowledge the use of Servicio General de Apoyo a la Investigación-SAI, Universidad de Zaragoza. MMA and EPP funded by Ministerio de Universidades and Unión Europea-NextGenerationEU “Requalification of Spanish university system for 2021-2023”. MPP is supported by the Spanish Ministry of Education, Culture and Sport (Grant Number FPU 16/03064). CNL is the recipient of a Juan de la Cierva-Formación contract (FJC2020-044561-I), supported by the MCIN and co-financed by the NextGenerationEU/PRTR. We thank the contribution of the two anonymous reviewers and the editor, Dr Gareth Dyke.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Fundação para a Ciencia e a Tecnologia [PTDC/CTA-PAL/31656/2017,UIDB/04035/2020]; Gobierno de Aragón [Group E18: Aragosaurus: Recursos Geológicos y Pal]; Ministerio de Educacion, Cultura y Deporte [FPU 16/03064]; Ministerio de Universidades Unión Europea-NextGenerationEU [Maria Zambrano. Requalification of Spanish univers]; Ministerio de Universidades (by Unión Europea-NextGenerationEU) [Maria Zambrano. Requalification of Spanish univers]; MCIN/AEI/10.13039/501100011033 and by the European Union ‘NextGenerationEU’/PRTR”, [FJC2020-044561-I,PLEC2021-008203]; Spanish Ministry of Science and Innovation [CGL2017-85038-P; MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR”,MCIN/AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR”, [FJC2020-044561-I,PLEC2021-008203].