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Home , Dimetrodon

By John R. DeGrace

A Time Before the wo hundred and ninety million years is more than a blink in time, Tbut still not so old as the earth goes. If the 4.5-billion year history of our planet were compressed to the span of a single day, then the rocks underlying Prince Edward Island would have been laid down at about 10:30 p.m. And yet what changes have taken place since then! At that time, our cli- mate was tropical. The geographic loca- tion now occupied by Charlottetown lay within five degrees of the equator, though already it was being pushed northward and away from Europe by the inexorable forces drivingthe continents slowly about the globe. The Gulf of St. Lawrence did not exist; instead, sand, silt and mud were being deposited into a complex low Bathygnathus Comes Home area now termed the "Maritimes Basin" from highlands to the south and west. bled them along before depositing them meeting of the Academy on 18 October These highlands were the Appalachian into sites commonly termed " beds." 1853. Dawson had sold him the fossilized Mountains, formed by the collision of For the most part these jumbled depos- remains of the left side of the face of a continents and at that time perhaps as its are unhelpfiil in unravelling the f aunal large , from just before the orbit of high as the present-day Himalayas. A history of the area. In the 1840s, how- the eye to a point close to the nostrils, with myriad of small streams flowing from ever, an important discovery was made several teeth preserved. Leidy gave the the naked mountain sides delivered to near New London. To this day, these animal represented by the specimen the the basin the raw materials for what we animal remains are the best preserved name Bathygnathus borealis Leidy; but he now know as the Prince Edward Island that have been found in Island rocks. did not know its affinities. When he pub- Redbeds. That time, a time before even lished his findings the following year in the dinosaurs, straddles the boundary the Academy's Journal, he asked, 'Was between the geological periods termed Bathygnathus borealis this animal probably not one of the bi- the and the . peds, which made the so-called tracks The low-lying areas along water- According to the folklore surrounding of the New Red Sandstone of the valley of courses, lakeshores, and the sea of the the fossil, it was found in 1845 by one the Connecticut?" It was not until 1963 Maritimes Basin teemed with life, of Donald McLeod at the 21-foot level of a that Wann Langston Jr. positively identi- which we have today only the most frag- well being dug by hand on a farm in the fied the animal as a specimen of mentary of records. Sometime after the North Shore community of French River. , a well-known sail-backed rep- sedimentary beds were deposited, they Some years later, possibly in 1852, tile of the Permo-Carboniferous period. were oxidized, acquiring the bright red McLeod gave the curiosity to John Dimetrodon was a most unusual ani- colour characteristic of the Island. In the William Dawson, the father of Prince mal, a scaly, carniverous that could process, delicate fossil material was de- Edward Island geology. Born and raised grow to lengths in excess of three me- stroyed. In rocks of similar age in Cape at Pictou, Nova Scotia, Dawson had tres. Long before the so-called "age of Breton, plant remains are preserved as begun exploring the Island's landforms dinosaurs," it exhibited characteristics carbon films, showing much detail. In as early as 1842, when he published a that are reminiscent of those we associ- Prince Edward Island, however, they report on the colony's fossils. By the ate with . Its teeth show differ- are reduced to mere compressions on time he received McLeod's offering, he entiation for ripping and tearing flesh bedding planes — like low-relief sculp- was deeply involved in the emerging effectively, in common with mammals tures — which must be viewed under science of paleontology. At the and unlike most . Most interest- oblique lighting conditions for any detail suggestion of his friend Sir Charles Lyell ing, perhaps, is its "sail" of skin sup- at all to be clear. (author of the first great textbook on ported on its back by bony spines. This Animal remains suffered in the oxidi- earth sciences, Principles of Geology), is generally considered to be a tempera- zation process as well, and they had the Dawson sent the specimen to the ture-regulating mechanism. When additional disadvantage of being re- Academy of Natural Sciences of Dimetrodon wanted to increase its body moved from the site of death. In most Philadelphia, where it was examined by temperature for hunting while its prey cases, the action of the swift-flowing palaeontologist Joseph Leidy, chair of was still sluggish in the mornings, it streams disarticulated—pulled apart— the Academy's board of curators. needed only to turn side-on to the rising the remains of dead and turn- Leidy unveiled the new acquisition at a sun and absorb the warmth of the rays

12 A Dimetrodonsoakingup a little morning the more correct name Apatosaurus, but Upon his retirement Dr. Prest gave sun. From C. L. Fenton andM. A. Fenton, the revision has not taken outside nar- the replica of Bathygnathus to Dr. H. W. The Fossil Book (New York: Doubleday, row scientific circles. (Walter) van de Poll, Chair of the De- 1989). partment of Geology at the University of New Brunswick. Van de Poll had been • Bathygnathusborealis Leidy compared The Long Road Home working on a new geological map of the with Dimetrodon limbatus; the Bathygnathus specimen is shaded. From The photograph reproduced here shows W. Langston, Jr., Fosil and a facsimile of the original fossil, which the Late Red Beds of Prince still resides in the Academy of Edward Island, National Museum of Natural Sciences of Phila- Canada Bulletin 187 (Geol. Ser. no. 56), delphia. When Wann Lang- 1963. ston Jr. began his studies of Prince Edward Island T A reproduction of the Bathygnathus fossils in the borealis Leidy fossil. The original remains early 1960s for the National at the Philadelphia Academy of Natural Museum of Canada, he was Sciences (No. 9524). permitted to borrow the original fossil for a short period. He had three high- into its sail, transferring the heat gained quality replicas of the fossil thereby to its body core by means of its made for study purposes. One of circulatory system. Similarly, it could shed these was placed in the Victoria heat by placing the sail with its edge to Museum in Ottawa, one was retained by Island, which was published by the De- the sun and radiating excess heat away. Dr. Langston for his own research, and partment of Energy and Forestry in 1983. Much more research will be necessary one was designated by him for display in Prest left it to Dr. van de Poll to decide before it can be established whether or Prince Edward Island. It took some thirty whether or not to return the specimen to not Dimetrodon is a part of the lineage years for his wishes in respect of Prince Prince Edward Island "when the time leading directly to the mammals. Edward Island to come true. was right." Van de Poll understood this Langston had been attracted to Prince to mean when provision had been made Edward Island by a colleague from the for safe storage and display. Geological Survey of Canada, Victor K. In August of 1992 the specimen was Prest, who needed expertise on fossil donated to the University of Prince from the Island. Dr. Prest had Edward Island to be placed in the Uni- been given office space for his field versity's permanent fossil collection. It studies above the Canton Cafe on has been made part of a public display of ower Queen Street. That space was Island fossils on exhibit at the Atlantic so being used for the storage of Veterinary College, University of Prince prospective museum materials by Edward Island, during 1992-93. B. Graham Rogers, then Director of Bathygnathus borealis Leidy has come Transportation in the provincial gov- home. ernment, but also designated as its "Geological Officer. "The reproduction fossil ended up being lodged there. Sources After Rogers' death in 1968, Dr. Prest happened upon the replica of The most persuasive analysis of A/V Services, UPEI Bathygnathus and, remembering its pur- Bathygnathus borealis is Wann Langston pose, took it to the Park Warden at the Jr.'s important study, Fossil Vertebrates The long-standing tradition in palae- Prince Edward Island National Park for and the Late Palaeozoic Red Beds of Prince ontological circles is that the name ac- exhibition. Revisiting the Park two years Edward Island, published in 1963 as corded a newly discovered animal group later, he found that the specimen still had National Museum of Canada Bulletin is that given by its discoverer. The sug- not been put on display. He recovered it No. 187. The discovery of the fossil, and gestion has been raised from time to and offered it to the provincial Minister of the quote from Leidy, are recounted time, then, that Bathygnathus should be Industry and Natural Resources, Cecil A. there. Walter van de Poll's newgeological made the operative name since it was Miller, and his Deputy, Patrick map of the province appears in Geology of discovered some years before the Murnaghan, to be transferred to the Prov- Prince Edward Island, Prince Edward we now cdllDimetrodon. This is not likely ince when a display case was ready for it. Island Department of Energy and to happen, since Dimetrodon has, to According to Prest, the two were excited Forestry Report 83-1 (1983). I amgrateful some extent, captured the public imagi- initially, but when they saw the small to Dr. Victor K. Prest for telling me about nation because of its unusual physical specimen nestled in newspapers in the his part in the story of how Bathygnathus features. In a similar vein, an attempt has trunk of Prest's car, they appeared to lose finally returned to the Island, MI been made in recent years to give the much of their interest. There was no well-known large Brontosaurus follow-up from government.

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