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Posts Tagged ‘Canis carcharias’

great white nice doggy

Nice doggy!  

As it is currently construed, the genus Canis includes certain dog-like species, including the dog/dingo/wolf species, the coyote, the Ethiopian wolf, and the jackals. However, recent genomic analysis suggests that this genus is paraphyletic, and it is in need of revision. In order to make Canis monophyletic, one wold have to include the dhole and African wild dog within the genus or create a genus for the side-striped and black-backed jackals.

But as messed up as the genus Canis is now, just imagine what it was like when there was a Canis carcharias.

This name is the old scientific name for the great white shark. “Canis” means dog in Latin, and “carcharis” means sharp and jagged in Greek.

It was never meant to reflect evolutionary relationships between dogs and sharks. Instead, it was just simple common scientific name that was given to this shark. Some early naturalists even used it as the generic name for all sharks, but my sources show that it almost always referred to the great white.

Classifying animals according to their evolutionary relationships is a very new development in science. Before that, animals were given scientific names based upon the whim of the classifier.

After all, before Buffon and Darwin, it was just assumed that all these creatures were divinely created and calling a shark a “sea dog” or “sea hound” made as much sense as using the term Canis carcharias to classify it.

The first person to use the scientific name Canis carcharias was Guillaume Rondelet, a professor of medicine at the University of Montpellier in southern France in sixteenth century.  Rondelet is considered the father of modern ichthyology, for he was the first to describe fishes and other marine creatures using clearly defined anatomical principles in his Libri de piscibus marinis in quibus verae piscium effigies expressae sunt (1556).  In the text, he describes several massive great whites, which the French and Italians called “lamia,” that were captured in Mediterranean. It’s from him that we get the apocryphal story of a great white that was capture with a full suit of armor in its stomach. These sharks were once quite common throughout the Mediterranean, and they were a very real problem for mariners and swimmers in that region. The reason why the French and Italians called them lamia is in reference to a child devouring sea monster in Greek mythology, and they were certainly very well aware of them.

Rondelet tried to describe this shark as something other than a great hulking sea monster. He tried place it as a naturally defined entity, and in this he did science a great service.

However, he lived before Linnaeus, so he didn’t use the Linnaean classification sytem. Canis was not the genus of the shark, and carcharias was not its species name.

It was just a name he divined, and unfortunately, because he was the first to do this, this became the scientific name used for the species for centuries afterward. In the early nineteenth century. Canis carcharias was still very commonly used to refer to great white sharks.

If one performs a simple search in Google Books for the term “Canis carcharias,” one will find any number of commentaries on great white sharks. However, Linnaeus himself called the species “Squalus carcharias” and dropped any reference  to dogs in the name.

And by the end of the nineteenth century, this name had finally fallen from favor.

Richard Lydekker describes “Rondeleti’s shark” in his The Royal Natural History: Fishes and Reptiles (1896.) The sizes are somewhat exaggerated:

The most formidable of all the existing members of the group is the gigantic Rondeleti’s shark (Carcharodon rondeletii), distinguished from the porbeagles by the great size of the broadly triangular teeth, which have strongly serrated edges, and may possess basal cusps. The existing species, which is a purely pelagic creature ranging over all the warmer seas, is known to attain a length of 40 feet, one of the teeth of a specimen of 36 feet in length measuring 2 inches along the edge of the crown, and 1 3/4 inches across the base. Similar teeth are found in the Crag deposits of Suffolk, and are referred to the existing species; but from these same beds, and also from the bottom of the Pacific, between Polynesia and Australia, there are obtained other teeth of much larger dimensions, some of them measuring upwards of 5 inches along the edge and 4 inches in basal depth. These teeth evidently indicate sharks beside which the existing form is a comparative dwarf; and it is not a little remarkable that the specimens dredged from the bed of the Pacific indicate that these giants must in all probability have survived to a comparatively recent date. Observations are still required as to the mode of life and breeding-habits of Rondeleti’s shark. Two other species of large sharks constitute the genus Odontaspis. With teeth almost indistinguishable from those of the porbeagles, these species differ by the second dorsal and anal fins being nearly as large as the first dorsal, and the absence of a pit at the root of the caudal fin, and of a keel on the sides of the tail (pg. 526).

In Lydekker’s time, it was now more acceptable to classify things using Linnaean taxonomy, and he was also trying to place this shark with its closest relatives. The great white is a giant mackerel shark, and he correctly placed it with the porbeagle, a type of shark that is actually quite common in British waters. (I was always told that porbeagle is a portmanteau between the words porpoise and beagle, another canine reference in shark nomenclature. However, other etymologies have been suggested.)

Further, Lydekker was using the new scientific name for the species that had been given to it by the Scottish zoologist Sir Andrew Smith, who had encountered them in his years as a naturalist in the Cape Colony. South Africa  is still a major stronghold for great white sharks, and they likely were more common in the 1820’s and 1830’s when Smith was living there.

The genus name  “Carcharodon” means jagged tooth, and the species name rondeletiirefers to Rondelet, who was the first to systematically describe the species.

However, Rondelet called the species Canis carcharias, so following the scientific tradition of allowing the first discoverer to name the species, we now call the great white Carcharodon carcharias.

It matter not that Rodelet wasn’t trying to classify the great white in the way we do now.

In fact, we really don’t use the same Linnaen system anymore.

We now used cladistic classification, which is why we’re now arguing about how to classify African wild dogs and black-backed jackals in the genus Canis and no serious person would try to call a great white shark a dog.

Great whites are sharks we’ve known for quite some time. They’ve likely attacked humans for thousands of years before we ever had any idea of what they were.

Ancient man just thought of them as evil sea monsters.

More advanced civilizations thought of them as great sea dogs.

And now we know them as amazingly derived mackerel sharks whose predatory prowess is rivaled by few other ocean creatures.

Ranging throughout the world’s oceans, the great white has been one of the most successful species of shark on the planet. Its ability to generate its own body heat has mean that it can travel into quite cold seas in search of marine mammal prey, and they have even been found 4,000 feet below the ocean’s surface.

But now the species is vulnerable.

We’ve killed them by the score. We have thought that if we killed off these sea demons, the oceans would be safe for everyone. Maybe even safe for democracy.

But the truth is the great white does play a vital role as one of the ocean’s top predators.

Without them, the ecosystem falls out of balance, and certain species begin to overpopulate.

We are only just now beginning to realize how important this giant sea dog actually is to maintaining the health of the oceans.

And we may have figured this out before it’s too late.

 

 

 

 

 

 

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