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Fossil whale’s tilted snout points to hunting on the seabed

A newly described pygmy sperm whale from Peru had an unusually lopsided skull and a heavy snout directed downwards. The peer-reviewed fossil study interprets this anatomy as suited to searching for prey in seabed sediment, widening the known feeding habits of this whale family beyond those of its living relatives.

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Frontal view of a Scaphokogia huachafo fossil skull on a laboratory support, showing its left-heavy cranial bones and thick downward-tilted snout.

A skull from Peru’s ancient coast

Scaphokogia huachafo, a newly described extinct pygmy sperm whale from southern Peru, had a skull whose bones were strikingly concentrated towards the left. The peer-reviewed anatomical research describes a fossil from rocks deposited along Peru’s ancient coast. Its heavy, downward-facing snout has prompted the researchers to propose that it searched for food near the seabed, unlike the deep-water feeding familiar in living relatives.[1], [2]

The skull was recovered at Aguada de Lomas, a fossil locality in Peru’s Sacaco area, in rocks of the Pisco Formation. It dates to approximately 6.3–5.6 million years ago. Closed joins between skull bones indicate an adult animal. The researchers found no crushing or burial deformation consistent with a later distortion of the skull, supporting the conclusion that the asymmetry belonged to the living whale.[1]

A heavy snout angled downwards

The snout points down by about 31 degrees and contains dense bone reinforced with cartilage that had turned to bone. Its robust, tubular shape distinguishes the animal from living pygmy sperm whales. The proposed feeding role concerns this combination of weight, orientation and skull architecture, rather than asymmetry alone. Living members of the family therefore offer an incomplete guide to the extinct animal’s ecology.[1]

Comparing skulls and head posture

Geometric comparisons used 31 groups of animals and 37 anatomical landmarks to place the skull among living and extinct toothed whales. A separate evolutionary analysis compared 38 units using 68 characters. The team also examined neck vertebrae from another fossil of the same genus to reconstruct how the head could bend towards the bottom. That neck posture was not preserved directly in the new species.[1]

A weighty snout directed into soft sediment could have helped the whale reach bottom-dwelling prey. Echolocation, locating objects from returning sound, is also proposed as part of its hunting behaviour. The sound-producing soft tissues did not survive fossilisation, so the complete hunting sequence remains an anatomical interpretation. The comparisons reveal an extinct skull design; rankings of the most asymmetric animals depend on which measurements are used.[1]

References

  1. News sourceCommunications BiologyA fossil whale’s skewed skull points to bottom feeding↩1↩2↩3↩4↩5
  2. News sourceAgencia AndinaA fossil whale’s skewed skull points to bottom feeding↩
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