On the mis-location of a giant sloth

To start off, I though you might be interested in a new series of pages on the National Park Service paleontology site, concerning the history of paleontology in NPS lands (including going back to before the sites were parks). We're always on the lookout for historical information. One odd case we've recently come across is a sloth which was at one time thought to come from a cave in the Mammoth Cave system.

It all began innocently enough with a paper by Richard Harlan in 1831, who reported on some sloth remains purchased for the Academy of Natural Sciences of Philadelphia (today the Academy of Natural Sciences of Drexel University). They had been obtained at least third-hand, with Harlan receiving them from a Mr. Dorfeuille of the Cincinnati Museum, who had bought them from the estate of a Mr. Clifford from Kentucky, who seemingly had obtained them from White Cave, Kentucky. White Cave is today part of Mammoth Cave National Park, but at the time was mined for saltpeter, used in gunpowder. The bones consisted of a molar tooth, five vertebrae, rib, two hand claws (one with a nonbony sheath), radius, humerus, scapula, tibia, partial femur, and fragments, pertaining to a young sloth.

Plate XII from Harlan (1831), illustrating the claws (1–2 and 3–4), radius (5–6), and molar tooth (7–9; I apologize that 7 and 8 are cut off) from the cave specimens.

As is frustrating with so many of these vintage publications, Harlan introduced the sloth remains as a new species, Megalonyx laqueatus, but didn't go right out and state that he was naming a new species, nor did he designate a type specimen. He further confused matters by also introducing some adult remains from Big Bone Lick. (If you're curious, M. laqueatus "White Cave" is no longer in use, whereas M. laqueatus "Big Bone Lick" grew up to become Paramylodon harlani.) Per Spamer et al. (1995), the "White Cave" material is catalogued as ANSP 12487–12490 and 12492–12499.

A photo of the sloth claw illustrated as 3 and 4 in Plate XII of Harlan (1831), included in Mercer (1897). As noted by Mercer, the claw includes the non-bony sheath.

The plot thickened the next year with the intrusion of Constantine Samuel Rafinesque, whom you might recognize in the brachiopod Rafinesquina. Outside of brachiopod circles, he is rather better known as a prodigiously prolific scientific character. In an 1832 publication, he reported that the caves of the Mammoth Cave area not only contained sloths, but also bones of bovids, a small carnivoran, and a shrew-like animal. Furthermore, according to him, Harlan's Megalonyx laqueatus did not come from White Cave, but from nearby Mummy Cave, and Rafinesque had already described it as Aulaxodon speleum. Far be it for me to impugn Rafinesque's version of events, but as far as I can tell the only place "Aulaxodon speleum" has ever been used seriously is in this very article, Rafinesque (1832), and even in 1832 the confident declaration that you had already named a species without actually doing any work toward this end was not going to fly. (Be that as it may, this article also appears to be the first report of fossils in the walls of the caves themselves, invertebrates he identified as Madrepores, a Mastrema, and a Turbinolite, all apparently corals of some flavor or another [and/or bryozoans since the line wasn't as firm them]).

Rafinesque's message did not go without response. In our old acquaintance George William Featherstonhaugh's short-lived "Monthly American Journal of Geology and Natural Science", he came in for a kicking from not only Harlan, but also the editor Featherstonhaugh himself in an uncredited review (Featherstonhaugh 1832). (Amusingly, both sides of the back-and-forth are in publications owned by the combatants.) Featherstonhaugh, warming up for his eventual abuse of Arkansas, devoted more than a half-dozen pages to laying into Rafinesque with all the gusto of a YouTube Star Wars critic. (Things haven't changed much in nearly 200 years, except back then you got yelled at in Dickensian English.) Within this there is space for an indignant letter from Harlan (p. 514) in which not only does he report that Rafinesque pumped him for information on the sloth before its publication, but that he borrowed a fish from Harlan and secretly sent it to Georges Cuvier with the information that it was a new genus and species. Harlan once again asserted the veracity of the late Mr. Clifford's locality information.

So, there we go. Everything is wrapped up in a neat package, Rafinesque is given a sound thrashing, just good clean wholesome early 1830s paleontological fun. But then...

Along came Gerard Troost, who in 1835 related that at least one of the sloth bones given to John Clifford and later to Harlan actually came from Big Bone Cave in Tennessee, so named for obvious reasons, and suggested that all of the "White Cave" sloth bones were from that site. (Incidentally, Big Bone Cave is also now protected, as both a State Natural Area and a National Natural Landmark.) The bones had been discovered at about the time of the War of 1812 when saltpeter was in particular demand. Some of the bones were given to a Squire Moses Fink, who gave a rib to Clifford and kept the rest for a natural history development that never occurred; these were later given to Troost. Troost reported that the rib was one of the bones illustrated by Harlan. At another point, a barrel of bones from Big Bone Cave had been sent to Clifford, who was apparently a major buyer of saltpeter from the cave. With this new information, Harlan (1835) agreed that yes, in all probability the sloth bones actually came from Big Bone Cave. In hindsight, a potential reason for the mis-location is that Big Bone Cave was formerly within White County, Tennessee (now within Van Buren County). It is not inconceivable that someone along the line garbled White County with White Cave. If Clifford was not actually obtaining bones himself but acquiring them alongside buying saltpeter from multiple caves, including White Cave, this kind of confusion could easily be introduced.

Henry Chapman Mercer had the most detailed follow-up after an excavation at Big Bone Cave in 1896 (Mercer 1897). Chapman wasn't a paleontologist per se, and his cave work is not what he's been remembered for, but he did have an uncanny knack for turning up at fossil-bearing caves (see also Hartman's Cave and Port Kennedy Cave for some previous examples). His interest was from the archeological side of things; for example, his work at Big Bone Cave was to investigate if sloth fossils found there were in any way associated with human artifacts found at the cave. A small number of sloth bones had been removed from the cave over the years, and Mercer and his party recovered another small group of bones. He came to the conclusion that all of the sloth bones found there probably belonged to the same young individual, and most likely included Harlan's specimens. If you're curious, Mercer did not find any definite association with artifacts, but did regard the sloth as geologically young. Not only were the fossils not mineralized, but they also included cartilaginous elements, and wads of hair and a coprolite found in the same layer may have also come from the sloth. (In an interesting if gruesome taphonomic observation, he suggested that a caked layer below the bones derived from fluids coming from the carcass.)

The stratigraphy of Big Bone Cave per Mercer (1897). Some caves are full of bat guano, or sloth or mammoth dung. This one was full of rat poop, produced by an eastern species of our old friend the packrat (Neotoma).

References

Featherstonhaugh, G. W. 1832. Rafinesque's Atlantic Journal. Monthly American Journal of Geology and Natural Science 1(11):508–515.

Harlan, R. 1831. Description of the fossil bones of the Megalonyx, discovered in “White Cave,” Kentucky. Journal of the Academy of Natural Sciences of Philadelphia 6(2):269–288.

Harlan, R. 1832. [Letter to the editor.] Monthly American Journal of Geology and Natural Science 1(11):514, footnote.

Harlan, R. 1835. Notice of the os ilium of the Megalonyx laqueatus, from Big Bone Cave, White County, Tennessee.​ Transactions of the Geological Society of Pennsylvania 1(2):347.

Mercer, H. C. 1897. The finding of the remains of the fossil sloth at Big Bone Cave, Tennessee, in 1896. Proceedings of the American Philosophical Society 36:36–70.

Rafinesque, C. S. 1832. The caves of Kentucky. Atlantic Journal, and Friend of Knowledge 1(1):27-30.

Spamer, E. E., E. Daeschler, and L. G. Vostreys-Shapiro. 1995. A study of fossil vertebrate types in the Academy of Natural Sciences of Philadelphia: taxonomic, systematic, and historical perspectives. The Academy of Natural Sciences of Philadelphia Special Publication 16.

Troost, G. 1835. On the localities in Tennessee in which bones of the gigantic mastodon and Megalonyx jeffersonii are found. Transactions of the Geological Society of​ Pennsylvania 1(1):139–146, 1(2):236–243.