Scaphokogia huachafo: fossil whale with both nostrils on its left, from one skull

The skull of an estimated 2.7-metre animal from Peru is so lopsided that its describers had to rule out crushing in the rock, and its seafloor diet is read from bone shape alone.

Peer reviewed · Fossil description · Single skull · Behaviour inferred from anatomy

A pygmy sperm whale that swam off Peru between 6.3 and 5.6 million years ago had both of its bony nostrils on the left side of its skull and a heavy snout bent 31° downward. Aldo Benites-Palomino, Gabriel Aguirre-Fernández and nine colleagues named it Scaphokogia huachafo in Communications Biology on 9 November 2026. They argue it fed on the seafloor, a specialised habit with no direct counterpart among living toothed whales. The species is known from one skull, and the feeding habit is inferred from its shape.

Evidence at a glance

Is this a big deal?

For whale anatomy, it is a solid step. The skull is real, well preserved and odd enough to redraw the outer edge of what a whale’s face can look like. The feeding story is an early, reasonable reading that needs more fossils. Any claim to the most lopsided face of any mammal should be held loosely: the paper itself says “potentially”, and it compared whales with other whales.

What scientists found

Toothed whales already have crooked faces. Their skulls are skewed around the nasal passages, a trait the paper links to the fatty, sound-producing structures in the forehead that they use for echolocation. Pygmy sperm whales, the family Kogiidae, take this further than most.

Scaphokogia huachafo takes it further again. In the paper’s diagnosis, both external bony nares (the nostril openings in the skull) sit left of the midline, and the left one is considerably larger than the right. The skew spreads beyond the nostrils. The bony structures in front of each eye socket differ in shape, and the bowl in the top of the skull that housed the sound-making organs is deepened unevenly.

The snout is the other oddity. It is a thick tube of unusually dense bone, stiffened by cartilage that had turned to bone, and it points 31° below the skull’s main axis. The two previously named species of the genus tilt less: about 16° to 21° in S. cochlearis and 27° in S. totajpe. The authors estimate the animal’s body length at roughly 2.7 m (about 8.9 ft). NOAA Fisheries lists about the same figure, 9 feet, as the upper length of today’s dwarf sperm whale.

The upper jaw has eight large tooth sockets, all filled in with spongy bone. The authors suggest the teeth were lost or reabsorbed as the animal grew. The species name comes from a word used in Peru for something bizarre, odd or extravagant.

How they found it

The skull, catalogued as MUSM 972 at the Museo de Historia Natural in Lima, was collected at Aguada de Lomas in the Sacaco basin of Arequipa, southern Peru. It comes from a layer of the Pisco Formation laid down in shallow sea between 6.3 and 5.6 million years ago, in the Late Miocene. The University of Zurich says it was found in the mid-1990s and that Benites-Palomino first studied it in 2015, as an undergraduate in Lima. He later did his doctorate at Zurich and is now at Friedrich-Alexander-Universität Erlangen-Nürnberg.

A skull this bent raises an obvious objection: perhaps the rock squashed it. The authors answer that distortion would show up elsewhere, and it does not: the joins between the skull bones are fully closed, and they report no fractures or warping in the rest of the skull. “This was genuine biology, not a result of poor preservation,” Benites-Palomino said in the university’s release.

To put a number on the skew, the team marked 37 points on the facial bones of 31 kinds of toothed whale: 11 sperm whales, 4 early toothed whales and 16 from the group that includes dolphins and porpoises. On overall face shape, S. huachafo sat at the extreme of its family, and it stayed at an extreme after the analysis accounted for family relationships.

The neck was harder. No neck bone survives with the new skull. A second fossil, MUSM 171, is the only Scaphokogia specimen that preserves the atlas, the first neck vertebra, though its exact species is unknown. Fitting that skull and atlas together, the team found the snout pointed 22° below the body axis with the neck fully raised and 55° with it fully lowered. SciQuest’s arithmetic: that is 33° of travel, and the snout never came up to level.

Why it matters to you

Nothing here changes your week. It speaks to the wonder lens: the sea off Peru once held a whale built for a job that toothed whales do not do this way today. Living sperm whales, large and small, are suction feeders that mostly take squid at depth, the paper notes.

The authors’ picture is something like a person sweeping a beach with a metal detector: the sensor is held angled at the ground and swung over the sand. The dense, down-pointing snout may have helped the whale hold itself near the bottom, and they propose its sonar searched soft sediment for prey. The comparison has a clear limit. A metal detector’s design is known; this whale’s sonar organs did not fossilise, so their size and aim are unknown.

What the evidence does not show

It does not show the animal eating. Bottom feeding rests on three anatomical clues: the down-turned snout, the heavy bone, and the neck range. Heavy bone is common in bottom-feeding marine mammals such as sea cows and walruses, the paper says, where it helps control buoyancy. That is consistent with life on the seafloor. Consistent is as far as it goes.

Those three clues also come from more than one animal. The snout angle is from the new skull. The neck range is from MUSM 171, and the paper labels its application to S. huachafo a hypothesised reconstruction. The CT scan used to map bone thickness was of the S. totajpe skull.

The record claim needs care too. When the team compared only the left and right premaxillae, the paired bones at the front of the upper jaw, the most lopsided species was S. totajpe, not the new one. The authors’ firm conclusion is about the genus: Scaphokogia is the most asymmetric group of whales in their sample. One statistical test of differences between whale groups gave p = 0.076, which the paper calls marginal. With one skull, nobody can say how much individuals of this species varied.

How this fits what we already knew

Lopsided whale skulls are old news in outline. A 2020 study in BMC Biology by Ellen Coombs and colleagues measured 162 living and extinct cetaceans and found that asymmetry in toothed whales is concentrated in the nose and face, with sperm whales and their relatives among the lineages where it increased. Baleen whales, which do not echolocate, were about as symmetric as cattle.

What changes is the extreme. Scaphokogia was named in 1988, and a second species, S. totajpe, followed in 2020. The new species is the most specialised of the three on the team’s family tree. It also had company. The Pisco Formation has yielded Odobenocetops, a walrus-like dolphin with a down-turned snout that earlier researchers also read as a bottom feeder. The authors take two such animals in one place as a sign of rich seafloor life and stable shallow seas, which they say lasted in the region until the Pliocene. For another case where a skull is the main evidence for how an animal fed, see the Tasmanian tiger’s skull and hunting style.

Independent view

SciQuest found no on-record comment from a researcher outside the team as of 10 November 2026, and could not request one during this automated run. The journal names Travis Park, a co-author of the 2020 asymmetry study, as one of the peer reviewers and has posted the review file; SciQuest has not read that file. We will add outside comment if we obtain it.

How other headlines framed it

The two independent reports we found both lead with a record. Sci.News calls the asymmetry record-breaking. Earth.com says the whale might hold the record for any mammal, and notes in its opening lines that the claim rests on a single skull. The University of Zurich release describes extreme asymmetry and gives the 55° head-down figure without naming the second specimen it was measured on. The paper’s own title pairs the asymmetry with bottom feeding. SciQuest’s headline reports the nostrils, which were observed, and keeps the one-skull limit in view.

What happens next

The 3D surface scans of the skull are public on MorphoMuseuM, so other researchers can remeasure it. The feeding idea would be tested best by a second S. huachafo skull, ideally with its neck bones, and by wider comparisons with other mammals before any all-mammal record is claimed. No follow-up dig or study has been announced that we could find. We will update this page if one is.

In one sentence

A single skull about 6 million years old from Peru shows a pygmy sperm whale with both bony nostrils on its left and a snout fixed pointing downward, which its describers read, without direct proof, as the kit of a seafloor feeder.

Read next

• Invictibellatrix, a dinosaur known from one braincase: how much a single specimen can and cannot support.
• Are killer whales dolphins or whales?: where toothed whales, sperm whales included, sit on the family tree.
• How fast was megalodon?: another large animal of Miocene seas.

Sources and disclosure

1. Benites-Palomino A., Sánchez-Villagra M. R., Paolucci F., Vélez-Juarbe J., Collareta A., Alfsen A., Dooley A., Omura D., Urbina M., Salas-Gismondi R., Aguirre-Fernández G. “Extreme cranial asymmetry in extinct benthic feeding sperm whales.” Communications Biology 9, 1406 (2026). doi:10.1038/s42003-026-11074-2. Received 4 June 2025, accepted 18 September 2026, published 9 November 2026. Open access, CC BY 4.0.
2. University of Zurich, 9 November 2026: Prehistoric Whale Reveals Extreme Skull Asymmetry (source of the quote, the discovery decade and the 2015 date).
3. 3D scans of the holotype: MorphoMuseuM, doi:10.18563/journal.m3.304.
4. Coombs E. J., Clavel J., Park T., Churchill M., Goswami A. “Wonky whales: the evolution of cranial asymmetry in cetaceans.” BMC Biology 18, 86 (2020). doi:10.1186/s12915-020-00805-4.
5. Benites-Palomino A., Vélez-Juarbe J., Salas-Gismondi R., Urbina M. “Scaphokogia totajpe, sp. nov., a new bulky-faced pygmy sperm whale (Kogiidae) from the late Miocene of Peru.” Journal of Vertebrate Paleontology 39 (6): e1728538 (issue dated 2019, online 2020). doi:10.1080/02724634.2019.1728538.
6. NOAA Fisheries species page: Dwarf sperm whale (length).

Disclosure: This article was drafted with AI assistance and checked against the sources above. SciQuest read the paper’s full main text but not its supplementary files or peer review file. Calculations by SciQuest: 55° − 22° = 33° of head travel; 270 cm = 2.7 m, about 8.9 ft. The authors declare no competing interests; the paper lists European Union NextGenerationEU funding for one author and open-access funding from the University of Zurich. The graphic is a SciQuest original schematic; no figures or photos from the paper or the release are used. Spotted an error? See our corrections policy.