Squalodon - The Shark Toothed Whale - Facts and Fossil Information about the Prehistoric Fossil Whale


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Squalodon Excavation Article by Paul R. Murdoch Jr.


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Location Where Squalodon Fossils Can Be Found:
Calvert Cliffs, MD


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Location Where Squalodon Fossils Can Be Found:
PCS Mine, Aurora, NC


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Extinct Long-Snouted Dolphin
Eurhinodelphis - Facts and Information


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Fossil Shark Gallery




My rendition of a squalodon, which could get around 10 feet in length (~3 meters)

This is my rendition of Squalodon calvertensis (Long-snouted shark Toothed Whale). Notice the large pectoral fins, reduced dorsal fin, mobile neck, the long beak, and the front teeth protruding from the jaw, creating small "tusks."
The body shape is based on an Irrawaddy Dolphin (Orcaella brevirostris), due to its large pectoral fins, mobile neck, and reduced dorsal fin. The head is based on many squalodon skulls, the body pattern is similar to a Rough-Toothed Dolphin (Steno bredanensis), because I think it looks cool!

Squalodon (Brandt, 1973)
The Shark Toothed Whale
Facts, Information, Fossil Examples, and Fossil Hunting Locations of Squalodon, The Shark Toothed Whales!

Squalodon Information Squalodon Fossil Identification Fossil Examples



Squalodon Facts and Information

General Overview
Squalodons lived from the early-middle Oligocene into the middle Miocene, roughly 33 to 14 million years ago. The squalodon genus belongs to the Odontocete Order, the toothed whales. Specifically it belongs to the Squalodontidae superfamily. This superfamily is named after the shark squallus, since its' cheek teeth superficially resemble the teeth of a squallus shark; hence the name "shark toothed whale". The Squalodontidae superfamily contains three different groups of medium-sized (roughly 3 meters in length - 10 ft) shark toothed whales. They are the short-snouted shark toothed whales (prososqualodon), the medium-snouted shark toothed whales (phoberodon), and the long-snouted shark toothed whales. This last group contains the genus squalodon.

Modern and Archaic Features - The Teeth
A strange mix of archaic and modern features characterizes these interesting prehistoric whales. One of the most noticeable archaic features of squalodons is their complex dentition. While other toothed whales were evolving simple conical teeth at this time, Squalodontidae retained their primitive teeth that their ancestors (the archaeocetis) had. For example their dentition is complex, their teeth are widely spaced apart, and their cheek teeth are triangular and serrated for grasping and cutting. An illustration of this similar archaeoceti dentition can be seen in figure 1.


Illustration of a squalodons skull compared to a zygorhiza skull, an archaeoceti
Here is my illustration of a squalodon skull compared to an archaeoceti's skull. The archaeoceti illustrated here is an Eocene zygorhiza, which was actually much larger than a squalodon. Notice how similar the molars are.

An actual skull (minus the mandibles) of a squalodon can be seen on public display at the Smithsonian Museum of Natural History in Washington, DC. Below is a picture of their skull on public display. The rear of the skull has been partially restored. Also, the front of the maxilla has also been restored. However the front "fangs" that stick straight out of the maxilla are not present.

A picture of the squalodon skull on public display at the Smithsonian Museum of Natural History in Washington DC.


The Neck
Another archaic quality the Squalodontidae possess is their necks. The necks are more compressed than archaeoceti; however they were probably more mobile than the other "modern looking" toothed whales at the time. Finally, paleontologists believe the dorsal fins were larger than archaeocetis, but still somewhat reduced.

Modern Characteristics - Blowhole and Echolocation
Despite these ancient features on Squalodontidae, they also had a mix of modern characteristics. For example, their craniums were well compressed and their rostrums were telescoped outward. This compression moved the nostrals toward the top of the head, giving them a similar appearance to modern toothed whales. Finally, squalodon skulls show evidence for the first appearance of echolocation. An illustration of a skull can be seen in figure 2.

Illustration comparing the skull of an archaoceti, a squalodon, and a modern dolphin
This illustration shows a comparison of three skulls, zygorhiza, squalodon, and phoca (a modern porpoise). Notice how the squalodon has it's nasal passages upward toward the cranium, instead of on the rostrum as the zygorhiza has (the nasal passages are shaded in black, the zygorhiza has one large one on its snout, whereas the other skulls have two small ones further back.) This is remarkably similar to the nasal passage placement on modern dolphins, thus showing modern characteristics. Also notice how asymmetric modern dolphin skulls are (the asymmmetry aids in echolocation). In reality, the eocene zyghoriza is much larger than a squalodon and dolphin.

Extinction and Fossil Occurence
These strange looking creatures could be found throughout the world in the Oligocene and Miocene. However, squalodons became extinct in the middle of the Miocene and left no descendants. Now, occasionally one can find an isolated tooth or bone from one of these great beasts while beach combing along the shores below the Calvert Cliffs of Maryland, or searching the Miocene and Oligocene exposures in NC and SC.

Species
There are at least two species of squalodon found along the Atlantic Coastal deposits. They all look similar, but are different in size, and have slight differences in tooth morphology. Squalodon whitmorei (Dooley, 2005) is the largest species, and Squalodon calvertensis (Kellogg, 1923) is the slightly smaller species with a longer snout. There are possibly other species of squalodon found in Europe (mainly Italy and France).

Squalodon atlanticus is a common species name attributed to numerous specimens, however, S. atlanticus is probably invalid. For an excellent explanation, Dr. Alton Dooley (THE expert on Squalodons) has a good summary on the VMNH website here.




Recommended Book to learn about early whales and whale evolution:
The following book: The Walking Whales: From Land to Water in Eight Million Years is a great book for learning about whale evolution. It is up to date (2014), and has all of the recent discoveries over the last few years.
Hans Thewissen gives a first hand account of the fossil discoveries, from their origins as small land dwelling mammals to modern whales. He is also one of the leading researchers in the field of whale paleontology. This is a great book for if you are interested in understanding whale evolution. Check it out.




For a good article on a squalodon excavation, click here



References:

Carrol, R. (1988). Vertebrate Paleontology and Evolution. NY: W.H. Freeman & Company.

Mchedlidze G.A.; Translated by Chakravarthy, R. (1984). General Features of the Paleobiological Evolution of Cetacea. New Delhi: Oxonian Press. Translated for Smithsonian Institution Libraries.



Squalodon Fossil Identification

Isolated teeth cannont be identified to a species level. One needs skull material to determine an exact species of squalodon.
Below are fossil identification images for Squalodon:

Fossil squalodon teeth - molar and incisor
Identification image for Squalodon teeth. The molars and incisors look very different.
Although this image says S. ?calvertensis, species determination cannot be done on isolated teeth, as there is tooth variation between individual animals.



fossil squalodon jaw fragment
Identification image for a Squalodon jaw. Squalodon jaw fragments are very easy to identify, as they had large teeth compared to other odontocetes living at that time. Because of this, they have very large root holes, whereas most of the other odontocetes had very small root holes.

For images of a better set of squalodon jaws, go to the Squalodon Excavation Article.




Sample Squalodon Fossils
squalodon tooth
This squalodon tooth with a broken root is probably a molar.

Formation:
squalodon fossil tooth
This is another molar with a broken root.

Formation:
fossil squalodon incisor
This is a squalodon incisor. Unfortunately the tip and root are broken.

Formation:
squalodon fossil tooth
This is probably a worn incisor (tip of tooth, and bottom of root are missing). Squalodon teeth are very hard to find, and much rarer than shark teeth, as whales do not constantly loose their teeth like sharks do. Also, these are less common than the more modern looking Mysteceti, or baleen whales, found here.


Formation:

Squalodon Jaw fragment
squalodon jaw fragment
This is a small jaw section from a Squalodon. Notice the large tooth socket.

Formation:



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