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Nobile F, Collareta A, Perenzin V, Fornaciari E, Giusberti L, Bianucci G. Dawn of the Delphinidans: New Remains of Kentriodon from the Lower Miocene of Italy Shed Light on the Early Radiation of the Most Diverse Extant Cetacean Clade. BIOLOGY 2024; 13:114. [PMID: 38392334 PMCID: PMC10887126 DOI: 10.3390/biology13020114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 01/29/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024]
Abstract
Nowadays, the infraorder Delphinida (oceanic dolphins and kin) represents the most diverse extant clade of Cetacea, with delphinids alone accounting for more than 40% of the total number of living cetacean species. As for other cetacean groups, the Early Miocene represents a key interval for the evolutionary history of Delphinida, as it was during this time span that the delphinidans became broadly distributed worldwide, first and foremost with the widespread genus Kentriodon and closely related forms. Here, we report on a new odontocete find from Burdigalian (20.4-19.0 Ma) deposits of the Friulian-Venetian Basin of northeastern Italy, consisting of the partial cranium of a small delphinidan with associated ear bones (right periotic, stapes, malleus and tympanic bulla). Osteoanatomical considerations and comparisons allow us to assign the studied specimen to the genus Kentriodon. This is the first confirmed record of Kentriodon from Europe as well as from the whole proto-Mediterranean region. Stratigraphic and phylogenetic considerations suggest that our new specimen may represent the geologically oldest member of Kentriodon. The evolutionary success of Kentriodon may correlate with the emergence of narrow-band high-frequency echolocation as a possible strategy to escape acoustic detection by large marine predators such as the squalodontids. In addition, the relatively high encephalization quotient of Kentriodon spp. may have provided these early dolphins with some kind of competitive advantage over the coeval non-delphinidan odontocetes.
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Affiliation(s)
- Francesco Nobile
- Dipartimento di Scienze della Terra, Università di Pisa, Via Santa Maria, 53, 56126 Pisa, Italy
- Dottorato di Ricerca Geoscienze e Ambiente, Università di Pisa, Via Santa Maria, 53, 56126 Pisa, Italy
| | - Alberto Collareta
- Dipartimento di Scienze della Terra, Università di Pisa, Via Santa Maria, 53, 56126 Pisa, Italy
- Museo di Storia Naturale, Università di Pisa, Via Roma 79, 56011 Calci, Italy
| | - Vittore Perenzin
- Museo Civico Archeologico, Via Lorenzo Luzzo, 23, 32032 Feltre, Italy
| | - Eliana Fornaciari
- Dipartimento di Geoscienze, Università di Padova, Via Giovanni Gradenigo, 6, 35131 Padova, Italy
| | - Luca Giusberti
- Dipartimento di Geoscienze, Università di Padova, Via Giovanni Gradenigo, 6, 35131 Padova, Italy
| | - Giovanni Bianucci
- Dipartimento di Scienze della Terra, Università di Pisa, Via Santa Maria, 53, 56126 Pisa, Italy
- Museo di Storia Naturale, Università di Pisa, Via Roma 79, 56011 Calci, Italy
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