By John R. DeGrace

A Time Before the Dinosaurs

Two hundred and ninety million years is more than a blink in time,

but 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 area now termed the "Maritimes Basin" from highlands to the south and west. These highlands were the Appalachian Mountains, formed by the collision of continents and at that time perhaps as high as the present-day Himalayas. A myriad of small streams flowing from the naked mountain sides delivered to the basin the raw materials for what we now know as the Prince Edward Island Redbeds. That time, a time before even the dinosaurs, straddles the boundary between the geological periods termed the Carboniferous and the Permian.

The low-lying areas along water-courses, lakeshores, and the sea of the Maritimes Basin teemed with life, of which we have today only the most frag-mentary of records. Sometime after the sedimentary beds were deposited, they were oxidized, acquiring the bright red colour characteristic of the Island. In the process, delicate fossil material was de-stroyed. In rocks of similar age in Cape Breton, plant remains are preserved as carbon films, showing much detail. In Prince Edward Island, however, they are reduced to mere compressions on bedding planes — like low-relief sculp-tures — which must be viewed under oblique lighting conditions for any detail at all to be clear.

Animal remains suffered in the oxidi-zation process as well, and they had the additional disadvantage of being re-moved from the site of death. In most cases, the action of the swift-flowing streams disarticulated—pulled apart— the remains of dead animals and turn-

Bathygnathus Comes Home bled them along before depositing them into sites commonly termed "bone beds." For the most part these jumbled depos-its are unhelpfiil in unravelling the f aunal history of the area. In the 1840s, how-ever, an important discovery was made near New London. To this day, these animal remains are the best preserved that have been found in Island rocks.

Bathygnathus borealis

According to the folklore surrounding the fossil, it was found in 1845 by one Donald McLeod at the 21-foot level of a well being dug by hand on a farm in the North Shore community of French River. Some years later, possibly in 1852, McLeod gave the curiosity to John William Dawson, the father of Prince Edward Island geology. Born and raised at Pictou, Nova Scotia, Dawson had begun exploring the Island's landforms as early as 1842, when he published a report on the colony's fossils. By the time he received McLeod's offering, he was deeply involved in the emerging science of paleontology. At the suggestion of his friend Sir Charles Lyell (author of the first great textbook on earth sciences, Principles of Geology), Dawson sent the specimen to the Academy of Natural Sciences of Philadelphia, where it was examined by palaeontologist Joseph Leidy, chair of the Academy's board of curators.

Leidy unveiled the new acquisition at a

meeting of the Academy on 18 October 1853. Dawson had sold him the fossilized remains of the left side of the face of a large animal, from just before the orbit of the eye to a point close to the nostrils, with several teeth preserved. Leidy gave the animal represented by the specimen the name Bathygnathus borealis Leidy; but he did not know its affinities. When he pub-lished his findings the following year in the Academy's Journal, he asked, 'Was this animal probably not one of the bi-peds, which made the so-called bird tracks of the New Red Sandstone of the valley of the Connecticut?" It was not until 1963 that Wann Langston Jr. positively identi-fied the animal as a specimen of Dimetrodon, a well-known sail-backed rep-tile of the Permo-Carboniferous period.

Dimetrodon was a most unusual ani-mal, a scaly, carniverous reptile that could grow to lengths in excess of three me-tres. Long before the so-called "age of dinosaurs," it exhibited characteristics that are reminiscent of those we associ-ate with mammals. Its teeth show differ-entiation for ripping and tearing flesh effectively, in common with mammals and unlike most reptiles. Most interest-ing, perhaps, is its "sail" of skin sup-ported on its back by bony spines. This is generally considered to be a tempera-ture-regulating mechanism. When Dimetrodon wanted to increase its body temperature for hunting while its prey was still sluggish in the mornings, it needed only to turn side-on to the rising sun and absorb the warmth of the rays

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A Dimetrodonsoakingup a little morning sun. From C. L. Fenton andM. A. Fenton, The Fossil Book (New York: Doubleday, 1989).

• Bathygnathusborealis Leidy compared with Dimetrodon limbatus; the Bathygnathus specimen is shaded. From W. Langston, Jr., Fosil Vertebrates and the Late Paleozoic Red Beds of Prince Edward Island, National Museum of Canada Bulletin 187 (Geol. Ser. no. 56), 1963.

T A reproduction of the Bathygnathus borealis Leidy fossil. The original remains at the Philadelphia Academy of Natural Sciences (No. 9524).

into its sail, transferring the heat gained thereby to its body core by means of its circulatory system. Similarly, it could shed heat by placing the sail with its edge to the sun and radiating excess heat away. Much more research will be necessary before it can be established whether or not Dimetrodon is a part of the lineage leading directly to the mammals.

A/V Services, UPEI

The long-standing tradition in palae-ontological circles is that the name ac-corded a newly discovered animal group is that given by its discoverer. The sug-gestion has been raised from time to time, then, that Bathygnathus should be made the operative name since it was discovered some years before the genus we now cdllDimetrodon. This is not likely to happen, since Dimetrodon has, to some extent, captured the public imagi-nation because of its unusual physical features. In a similar vein, an attempt has been made in recent years to give the well-known large dinosaur Brontosaurus

the more correct name Apatosaurus, but the revision has not taken outside nar-row scientific circles.

The Long Road Home

The photograph reproduced here shows a facsimile of the original fossil, which still resides in the Academy of Natural Sciences of Phila-delphia. When Wann Lang-ston Jr. began his studies of Prince Edward Island vertebrate fossils in the early 1960s for the National Museum of Canada, he was permitted to borrow the original fossil for a short period. He had three high-quality replicas of the fossil made for study purposes. One of these was placed in the Victoria Museum in Ottawa, one was retained by Dr. Langston for his own research, and one was designated by him for display in Prince Edward Island. It took some thirty years for his wishes in respect of Prince Edward Island to come true.

Langston had been attracted to Prince Edward Island by a colleague from the

Geological Survey of Canada, Victor K. Prest, who needed expertise on fossil bones from the Island. Dr. Prest had been given office space for his field studies above the Canton Cafe on ower Queen Street. That space was so being used for the storage of

prospective museum materials by B. Graham Rogers, then Director of Transportation in the provincial gov-

ernment, but also designated as its "Geological Officer. "The reproduction

fossil ended up being lodged there. After Rogers' death in 1968, Dr.

Prest happened upon the replica of Bathygnathus and, remembering its pur-pose, took it to the Park Warden at the Prince Edward Island National Park for exhibition. Revisiting the Park two years later, he found that the specimen still had not been put on display. He recovered it and offered it to the provincial Minister of Industry and Natural Resources, Cecil A. Miller, and his Deputy, Patrick Murnaghan, to be transferred to the Prov-ince when a display case was ready for it. According to Prest, the two were excited initially, but when they saw the small specimen nestled in newspapers in the trunk of Prest's car, they appeared to lose much of their interest. There was no follow-up from government.

Upon his retirement Dr. Prest gave the replica of Bathygnathus to Dr. H. W. (Walter) van de Poll, Chair of the De-partment of Geology at the University of New Brunswick. Van de Poll had been working on a new geological map of the

Island, which was published by the De-partment of Energy and Forestry in 1983. Prest left it to Dr. van de Poll to decide whether or not to return the specimen to Prince Edward Island "when the time was right." Van de Poll understood this to mean when provision had been made for safe storage and display.

In August of 1992 the specimen was donated to the University of Prince Edward Island to be placed in the Uni-versity's permanent fossil collection. It has been made part of a public display of Island fossils on exhibit at the Atlantic Veterinary College, University of Prince Edward Island, during 1992-93. Bathygnathus borealis Leidy has come home.

Sources

The most persuasive analysis of Bathygnathus borealis is Wann Langston Jr.'s important study, Fossil Vertebrates and the Late Palaeozoic Red Beds of Prince Edward Island, published in 1963 as National Museum of Canada Bulletin No. 187. The discovery of the fossil, and the quote from Leidy, are recounted there. Walter van de Poll's newgeological map of the province appears in Geology of Prince Edward Island, Prince Edward Island Department of Energy and Forestry Report 83-1 (1983). I amgrateful to Dr. Victor K. Prest for telling me about his part in the story of how Bathygnathus finally returned to the Island, M I

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