Living Fossils!

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The first question which presents itself for solution is, from whence came the animal? Are we to consider it as the type of a genus which has become extinct and not yet fossil? or does it owe its present locality to accident, having been brought from some distant and unexplored country, and heretofore escaped the eye of the naturalist?1

Thus the anatomist Richard Harlan queried the origin of a skull he scientifically described in the first American summary of the mammalian fauna of North America, Fauna Americana, published in Philadelphia in 1825. For a long time, natural historians balked at the idea of the absolute extinction of species, and the viewpoint, conceived and perpetuated by scholars in the Old World, was transferred to researchers in America. In 1797 Thomas Jefferson publicized his Megalonyx bones, seeking to advance the cause of American science and American scholarship. He was a vehement champion for the uniqueness of America fauna; not that it was superior in any way to that of the Old World, but that it was its equal.2 But Jefferson nonetheless remained a disciple of the whole view of natural history as devised in the Old World. In so doing, he intimated that Lewis and Clark might find living vestiges of animals that had been displaced beyond the western frontier by the encroaching human settlements.

This was not as radical an idea as one might suppose. When he introduced Megalonyx to the scientific community in 1797 (published in 1799), Thomas Jefferson was perplexed: "A difficult question now presents itself," he wrote. "What is become of the great-claw?"3 Here were the bones of what he believed was a formidable predator, yet no living person that he knew of had ever seen a live one.

Jefferson understood that animals such as elephants, rhinoceroses, lions, and tigers do not live in areas inhabited by humans, but instead "have their haunts nearest the inhabited frontier, enter it occasionally, and commit depredations when pressed by hunger: but the mass of their nationÖnever approach the habitation of man, nor are within reach of it." He cited earlier accounts, from the 16th and 17th centuries, some of them from American Indian lore, that "lions" had been seen in North America, and that as recently as the late 1700s--Jefferson's time--there had been reports of "tremendous roaring" heard, and terrifying animals sighted, in the remotest regions of the eastern United States.4 Drawing an analogy with the more leisurely reproduction rates of large predators and more prolific smaller fauna, Jefferson opined: "It is probable then that the great-claw has at all times been the rarest of animals. Hence so little is known, and so little remains of him. His existence however being at length discovered, enquiry will be excited, and further information of him will probably be obtained" But always, Jefferson wrote, "the progress of the new population [of humans] would soon drive off the larger animals, and the largest first."5

Most tantalizing of Jefferson's conjectures was his remarkable suggestion--perhaps hope--that the largest of the enigmatic creatures were alive in the West. He wrote this originally in 1797, six years before the U.S. purchased Louisiana Territory and before the Lewis and Clark Expedition set out. (Jefferson asked George Rogers Clark to lead an expedition to the Pacific in 1797.)

In the present interior of our continent there is surely space and range enough for elephants and lions, if in that climate they could subsist; and the mammoths [mastodons] and megalonyxes who may subsist there. Our entire ignorance of the immense country to the West and North-West, and of its contents, does not authorise us to say what it does not contain.6

The idea that animals--unknown to humans or known only from their bones--had fled unseen before an advancing juggernaut of towns and farms seems preposterous to us today. Even decades after the Lewis and Clark expedition it still was a reasonable, albeit controversial, view as demonstrated by a little skull that Meriwether Lewis probably saw for himself when he visited Philadelphia in 1803. It was an empirical example of the mysteries of unknown creatures, one which might have produced for Lewis some further inspiration for finding marvelous animals in the West.

Osteopera platycephala Harlan
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Osteopera platycephalus

In zoology and botany, a "type" specimen is the original specimen (or one of several) that was used by the author of a species name when he or she first formally published it. A type specimen thus is the taxonomic definition of the species it represents, and against which all later comparisons are made.

The skull, found along the banks of the Delaware River around 1795, was on display for years in Charles Willson Peale's museum in Philadelphia. Sometime before 1825, Richard Harlan examined it and included a description of it in his Fauna Americana. Thinking it was an entirely new kind of animal, he named it Osteopera platycephala ("flat-headed pouch-bone"). He said it was a new genus and species of mammal, and it was known only by this unique skull. Harlan specially took note that "This cranium has been frequently examined by the curious, and by them regarded as a lusus naturae [a trick of nature]."7 Indeed, the little skull tricked Harlan himself. The scenario is a good illustration that scientific work is progressive; one learns from mistakes as well.

Despite his rhetorical question (quoted above) about whether the animal had just become extinct, Harlan rather imagined that its kind had been displaced by human settlement along the Delaware River, and that this individual didn't make it away:

Suppose an animal to inhabit the shores of the great rivers of America previous to the discovery of this continent, and not to be endowed with the instinct of emigration, to become surrounded by the habitations of civilized man; hemmed in, and cut off from all resources by the march of civilization, the natural consequences would be destruction.8

The clue to the real identity of Osteopera platycephala was actually close at hand. Once Harlan published its description, the animal was immediately recognized by other researchers. It was a creature known to be alive in Central and South America–the paca, Coelogenys paca ("hollow-cheeked paca"), a species of nocturnal rodent originally named by Carl Linnaeus in 1766. Why no one had properly identified it while it lay for years in Peale's museum, "examined by the curious," is a mystery. After the publication of Fauna Americana, John Godman, a well-known physician and medical editor, immediately published unsigned reviews of Harlan's monograph and took him to task severely, with blistering accusations of plagiarism and sloppy research.9

Harlan, in his own defense, said that the animal "was never affirmed to be extinct" and claimed, "we have never attempted to conceal it."10 He seems to have been influenced by the lingering worldview of naturalists who argued against extinction. And he had not considered that a foreign animal may have been a shipboard pet or cargo, which wound up on the bank of the Delaware River either as an escapee or a dead body.

Even though Harlan was wrong in his taxonomic identification, he had toyed with the concept of extinction, but in the end refused to accept it; instead he sent Osteopera platycephala, alive, into the wilderness, perhaps to be yet discovered.

This tangle with reality is the kind of academic legacy that Meriwether Lewis faced two decades earlier. The American fauna was not made up of degenerate forms of Old World animals. And it was not beyond the realm of possibility to find those elusive mastodons and megalonyxes alive. To imagine this sort of thing must have inspired awe in Lewis.


1. Richard Harlan, Fauna Americana: Being a Description of the Mammiferous Animals Inhabiting North America (Philadelphia: Anthony Finley, 1825), 130-131.

2. Jefferson, "Memoir On the Discovery of Certain Bones," p. 258. He held this position as early as 1785, when he discussed it in his Letters On the State of Virginia (about which see more below).

3. Ibid., 251.

4. Ibid., 251-253.

5. Ibid., 256.

6. Ibid., 252.

7. Harlan, Fauna Americana, 129.

8. Ibid., 131.

9. Unsigned [John Godman], [Review of Richard Harlan's] "Fauna Americana," North American Review, vol. 50 (new series, vol. 25), pp. 122, 134. X. [John Godman], "Remarks on an Article in the North American Review," Franklin Journal, and American Mechanics' Magazine, vol. 1, no. 1 (January 1826), p. 20. In fact, Godman's most scathing–even unprofessional–remarks were saved as handwritten notes in what may have been his own copy of Fauna Americana (now in the library of the American Philosophical Society). On page 131, adjacent to Harlan's published remarks on the historical demise of the animal--"Suppose an animal to inhabit the shores of the great rivers..."--Godman penned in snide, silent reply, "ëSuppose' that this genus should prove to be all ëfudge'." And on page 126, next to Harlan's introduction of the new genus and species names, Osteopera platycephala, Godman wrote for himself, sarcastically in Latin, "Io! triumphe! Bisdicite Io! Paean!" (which has various meanings, but generally, "Hurrah! Triumph! Two names, hurrah! A hymn of victory!").

10. Richard Harlan, "Refutation of Certain Misrepresentations Issued Against the Author of the ëFauna Americana,' in the Philadelphia Franklin Journal, No. 1, 1826, and in the North American Review, No. 50," privately published, printed by William Stavely (Philadelphia, 1826), 21-22.

Funded in part by a grant from the National Park Service, Challenge-Cost Share Program.