Extreme cranial asymmetry in extinct benthic feeding sperm whales
Abstract
The fossil record provides critical insights into morphological changes beyond those observable in extant species, revealing evolutionary novelties. Among mammals, toothed cetaceans are notable for pronounced cranial asymmetry associated with sound-emitting forehead structures. Pygmy sperm whales (Kogiidae),display some of the most extreme cranial asymmetries known. Here, we describe Scaphokogia huachafo sp. nov., a new pygmy sperm whale species from the Late Miocene Pisco Formation, Peru. This species is characterised by extreme craniofacial asymmetry that extends beyond the external bony nares to the surrounding cranial structures. Geometric morphometric and symmetry analyses centred on S. huachafo indicate that this genus exhibits the most extreme facial asymmetry documented among cetaceans, and potentially among mammals. Distinct morphological traits include a robust, ventrally oriented, tubular rostrum composed of dense pachyostotic bone and reinforced by ossified cartilage. Morphological reconstruction of the atlanto-occipital joint in closely related congeners suggest enhanced ventral neck flexibility in Scaphokogia , which in turn is consistent with a benthic foraging behaviour. This extreme cranial morphology likely represents a unique adaptation with no direct modern analogues – one that greatly expands the known diversity of cetacean skull architecture. S. huachafo demonstrably occupied extinct ecological niches, revealing pivotal benthic foraging shifts during the Late Miocene.
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BibTeX
@article{benitespalomino2026extreme,
title = {{Extreme cranial asymmetry in extinct benthic feeding sperm whales}},
author = {Aldo Benites-Palomino and Marcelo R. Sánchez-Villagra and Florencia Paolucci and Jorge Vélez-Juarbe and Alberto Collareta and Apolline Alfsen and Alton Dooley and Dan Omura and Mario Urbina and Rodolfo Salas-Gismondi and Gabriel Aguirre-Fernández},
journal = {Communications Biology},
year = {2026},
month = nov,
doi = {10.1038/s42003-026-11074-2},
url = {https://www.nature.com/articles/s42003-026-11074-2},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Extreme cranial asymmetry in extinct benthic feeding sperm whales
AU - Aldo Benites-Palomino
AU - Marcelo R. Sánchez-Villagra
AU - Florencia Paolucci
AU - Jorge Vélez-Juarbe
AU - Alberto Collareta
AU - Apolline Alfsen
AU - Alton Dooley
AU - Dan Omura
AU - Mario Urbina
AU - Rodolfo Salas-Gismondi
AU - Gabriel Aguirre-Fernández
PY - 2026
DA - 2026/11/09
JO - Communications Biology
DO - 10.1038/s42003-026-11074-2
UR - https://www.nature.com/articles/s42003-026-11074-2
AB - The fossil record provides critical insights into morphological changes beyond those observable in extant species, revealing evolutionary novelties. Among mammals, toothed cetaceans are notable for pronounced cranial asymmetry associated with sound-emitting forehead structures. Pygmy sperm whales (Kogiidae),display some of the most extreme cranial asymmetries known. Here, we describe Scaphokogia huachafo sp. nov., a new pygmy sperm whale species from the Late Miocene Pisco Formation, Peru. This species is characterised by extreme craniofacial asymmetry that extends beyond the external bony nares to the surrounding cranial structures. Geometric morphometric and symmetry analyses centred on S. huachafo indicate that this genus exhibits the most extreme facial asymmetry documented among cetaceans, and potentially among mammals. Distinct morphological traits include a robust, ventrally oriented, tubular rostrum composed of dense pachyostotic bone and reinforced by ossified cartilage. Morphological reconstruction of the atlanto-occipital joint in closely related congeners suggest enhanced ventral neck flexibility in Scaphokogia , which in turn is consistent with a benthic foraging behaviour. This extreme cranial morphology likely represents a unique adaptation with no direct modern analogues – one that greatly expands the known diversity of cetacean skull architecture. S. huachafo demonstrably occupied extinct ecological niches, revealing pivotal benthic foraging shifts during the Late Miocene.
SN - 2399-3642
ER -