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| Eophyseter damarcoi |
Abstract
A new sperm whale species is described from the late Zanclean (Early Pliocene) of Piedmont, northwest Italy, based on a partial vertebral column and parts of the forelimb. The new taxon, Eophyseter damarcoi gen. nov. sp. nov., is characterized by elongated vertebral centra in the thoracic and lumbar regions of the vertebral column, wider and higher articular facets for the occipital condyles in the atlas, elliptical and dorsoventrally compressed posterior articular facet of the axis-bearing block, ulna with posteriorly convex margin. These characters distinguish Eophyseter damarcoi gen. nov. sp. nov.from other physeteroids and show that the vertebral proportions are differently arranged with respect to those of the extant sperm whale species. A phylogenetic analysis was performed to understand the relationships of Eophyseter damarcoi gen. nov. sp. nov. by adding 20 postcranial characters to a previous character x taxon matrix; it revealed that E. damarcoi gen. nov. sp. nov. forms a clade with P. macrocephalus. A taphonomic analysis suggested that the carcass of the holotype specimen of Eophyseter damarcoi gen. nov. sp. nov. was exploited by sharks and colonized by barnacles and molluscs; however, a quick burial prevented its total destruction by other invertebrates, as usual in the cetacean fossil record from the Pliocene of Piedmont.
Keywords: Italy; Physeteridae; Phylogeny; Eophyseter; Physeteroidea; Piedmont; Pliocene; Postcranial skeleton.
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| Reconstruction of the sperm whale Eophyseter damarcoi gen. nov sp. nov. (MGPTPU 13864, holotype). B) Piero Damarco, to whom Eophyseter damarcoi gen. nov. sp. nov. is dedicated, applying the final touch to the skeleton MGPT-PU 13864 on display in Asti. |
Class MAMMALIA Linnaeus, 1758
Order Cetacea Brisson, 1762
Clade Neoceti Fordyce & Muizon, 2001
Parvorder Odontoceti Flower, 1867
Superfamily Physeteroidea Gray, 1868
Family Physeteridae Gray, 1821
Genus Eophyseter gen. nov.
Etymology: Eo is a Greek word (ήώς) that means dawn, meaning ancestral, old. Physeter derives from the Greek φυσώ meaning blower. Diagnosis of genus: Eophyseter damarcoi gen. nov. sp. nov. shows a unique morphology of the atlas, in the axis-bearing cervical block, in the proportions of the vertebral column and in the ulna.
Diagnostic characters are the following: (1) the atlas is characterized by articular facets for the occipital condyles that protrude dorsally to the body of the vertebra and reach the height of the superior surface of the neural arch; (2) the articular surface for occipital condyles are comparatively wider than those of all the other physeteroids in which the atlas is preserved, and their ventromedial portion is comparatively longer; (3) in the axis-bearing cervical block, the epiphysis of the 7th cervical vertebra is dorsoventrally compressed and transversely widened to form showing an elliptical outline (it is transversely narrow and rounder in all the other physeteroids in which the axis-bearing block is preserved); (4) the lengths of the vertebral centra are comparatively more elongated than those of physeterids in which the vertebral column is known; in particular, in a long portion of the thoracic and lumbar regions of the vertebral column, the lengths of the centra are almost equal to the corresponding widths and heights (this pattern contrasts with that of extant sperm whales in which the length values are lower than those of heights and widths); (5) the posterior border of the ulna is posteriorly convex rather than being straight or concave as in other physeterids in which the ulna is preserved.
Eophyseter damarcoi gen. nov. sp. nov.
Etymology: The patronymic damarcoi is to honor Piero Damarco (Fig. 2B) who coordinated and executed extensive preparation of the specimen and who dedicated his life to the discovery and curation of the fossil treasures of Piedmont, Northwest Italy
Michelangelo Bisconti, Riccardo Daniello, Riccardo Stecca and Giorgio Carnevale. 2025. A New Pliocene Sperm Whale from Vigliano D’Asti, Piedmont, Northwest Italy. RIVISTA ITALIANA di PALEONTOLOGIA e STRATIGRAFIA. 131(1): 139-175. DOI: doi.org/10.54103/2039-4942/22338