Systematic Revision of the Oligocene Billfishes (Istiophoriformes: Palaeorhynchidae) from Romania

Grădianu, Ionuț; Monsch, Kenneth A.; Baciu, Dorin Sorin

doi:10.3390/d17060393

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Systematic Revision of the Oligocene Billfishes (Istiophoriformes: Palaeorhynchidae) from Romania

by

Ionuț Grădianu

^1,2,*

,

Kenneth A. Monsch

³ and

Dorin Sorin Baciu

⁴

¹

Natural Sciences Museum of Piatra-Neamţ, Petru Rareș no. 26, RO-610119 Piatra-Neamț, Romania

²

Faculty of Biology, Geology, Babeş-Bolyai University, Gheorghe Bilaşcu Street, RO-400015 Cluj-Napoca, Romania

³

Naturalis, Biodiversity Centre, Department of Vertebrate Evolution, Development and Ecology, P.O. Box 9517 2300 RA Leiden, The Netherlands

⁴

Department of Geology, Faculty of Geography and Geology, “Alexandru Ioan Cuza” University of Iaşi, B-dul Carol I, Nr. 20 A, RO-700505 Iasi, Romania

^*

Author to whom correspondence should be addressed.

Diversity 2025, 17(6), 393; https://doi.org/10.3390/d17060393

Submission received: 27 April 2025 / Revised: 29 May 2025 / Accepted: 30 May 2025 / Published: 31 May 2025

(This article belongs to the Special Issue Diversity, Biogeography and Evolution of Actinopterygians)

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Abstract

This study revises †Palaeorhynchidae (Istiophoriformes), a rare and taxonomically disputed group within Romania’s Oligocene ichthyofauna. Historically placed within Scombroidei, Istiophoriformes is now supported by molecular phylogenetics as a distinct lineage. However, prior Romanian fossil descriptions, often fragmentary, require critical revision to resolve their phylogeny, ecology, and biogeography. Outdated classifications must align with modern systematics. Our analysis confirms only two valid istiophoriform taxa in Romania’s Oligocene: †Homorhynchus colei, previously misassigned to †Palaeorhynchus longirostris or †P. glarisianus, and †Palaeorhynchus humorensis. This clarifies long-standing taxonomic uncertainties and underscores the need for integrative approaches in paleoichthyology. The findings refine regional Oligocene biodiversity records and highlight the Eastern Carpathians’ significance in understanding marine ecosystems of the epoch.

Keywords: Oligocene; billfishes; Piatra-Neamț; Gura Humorului; Romania

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MDPI and ACS Style

Grădianu, I.; Monsch, K.A.; Baciu, D.S. Systematic Revision of the Oligocene Billfishes (Istiophoriformes: Palaeorhynchidae) from Romania. Diversity 2025, 17, 393. https://doi.org/10.3390/d17060393

AMA Style

Grădianu I, Monsch KA, Baciu DS. Systematic Revision of the Oligocene Billfishes (Istiophoriformes: Palaeorhynchidae) from Romania. Diversity. 2025; 17(6):393. https://doi.org/10.3390/d17060393

Chicago/Turabian Style

Grădianu, Ionuț, Kenneth A. Monsch, and Dorin Sorin Baciu. 2025. "Systematic Revision of the Oligocene Billfishes (Istiophoriformes: Palaeorhynchidae) from Romania" Diversity 17, no. 6: 393. https://doi.org/10.3390/d17060393

APA Style

Grădianu, I., Monsch, K. A., & Baciu, D. S. (2025). Systematic Revision of the Oligocene Billfishes (Istiophoriformes: Palaeorhynchidae) from Romania. Diversity, 17(6), 393. https://doi.org/10.3390/d17060393

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Systematic Revision of the Oligocene Billfishes (Istiophoriformes: Palaeorhynchidae) from Romania

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