Elgin Reptiles Explained

Elgin Reptiles is the name given to the Permian and Triassic fossils found in the sandstone deposits in and around the town of Elgin, in Moray, Scotland. They are of historical and scientific importance, and many of the specimens are housed in the Elgin Museum, and some in the Hunterian in Glasgow, and the National Museum of Scotland in Edinburgh. The Elgin Reptiles include the dinosauriform Saltopus elginensis,[1] the dicynodont Gordonia,[2] and the pareiasaur Elginia.[3] There are also many footprints and tail-drags associated with the same Permian and Triassic sandstone deposits.[4] [5]

History

The sandstone in the Elgin area was originally quarried for building materials. The quarries were where the first reptile fossils were found, and they have continued to yield fossils to this day.[5] The first Elgin Reptile was discovered in 1844, but because it was only a few scales scientists of the time believed it was an Old Red Sandstone fish fossil,[5] which were relatively well-known from sites across Northern Scotland. In 1851 a second indisputably reptilian fossil was found. Fossils of Gordonia were first found by Scottish naturalist Ramsay Heatley Traquair in 1885 and E.T. Newton described several key fossil specimens.[2]

Elgin Museum is Scotland's oldest independent museum.[6] The Elgin Reptiles, footprints, and older fish fossils held by the Elgin Museum are “recognised” by the Scottish Government as a Collection of National Significance due to the major part played by the Museum’s founders and associated geologists in helping answer questions about geological succession that challenged 19th century naturalists. The Museum has many original papers, including letters from Hugh Miller, and correspondence with Charles Darwin.[3]

Geological background

The land North of Elgin consists of fragments of Permian, Triassic and Jurassic bedrocks on the edge of the Moray Firth Basin, south of the Great Glen Fault. The Elgin Reptiles come from the Permian and Triassic rocks. These are called the Hopeman Sandstone Formation and the Burghead Sandstone Formation, both part of the New Red Sandstone Supergroup.[7] Some marine reptiles have been found in a glacial erratic of Jurassic strata. Most of the sandstones are wind-blown desert dune deposits, but there are some river deposits and the later Jurassic deposits include mudstones.[8] These rocks overly much older Devonian lake deposits from Lake Orcadie. The intervening Carboniferous sediments were eroded before the Permian deposition, leaving a 100 million year gap in the stratigraphy. This unusual sequence of rocks confused 19th century geologists for many years.The Moray Firth Basin has been exploited for offshore oil deposits. Scotland lay at about 20 degrees North in the Late Permian-Early Triassic, and was moving North.[8] [5] Permian, Triassic and Jurassic rocks are rare in Scotland, but some can be found along the Northern edge of the Moray Firth, and in the Inner Hebrides, particularly on the Isle of Skye. The Hopeman Sandstone Formation quarry at Clashach is designated as a SSSI (Site of Special Scientific Importance) for its fossils.

Fossils

Many of the Elgin Reptile fossils contain no actual bone: they are often voids in the sandstone that used to contain bone, but are now virtually empty. This made them difficult to identify and study. In the 19th century until the late 20th century, the most common method to explore them was to infill the void, then break the surrounding rock.[4] [5] [9] More recently, CT-scanning has been used to see inside the rock and reconstruct the fossils digitally. These can also be printed or cast as models to facilitate study and as museum pieces. Elgin Museum has such a cast of the dicynodont Gordonia.[3] [4] The reptiles of Cutties Hillock, Quarrywood and the Hopeman Sandstones are Late Permian, around 250 million years old, while most other reptile fossils are found in the early Triassic rocks of Lossiemouth, Spynie and Findrassie, and are about 220 million years old.[5] The fossils are “recognised” by the Scottish Government as a Collection of National Significance.[3] Many of the type and significant specimens are on display, with more fossils and archives in the collection at Elgin Museum, available for study and research.

More recent fossil discoveries from Elgin have been footprints, with over 200 found prior to 1997.[4] These range in size from 0.5 cm to 24 cm wide, and most belong to therapsids.[4] [5] Numerous taildrags have also been recovered and studied, many from therapsids.[4]

Archosaurs

Elgin Reptiles: Archosaurs
TaxaPresenceLocationDescriptionImages
TriassicLossiemouth, Spynie, and Findrassie ScotlandA 1.2adj=midNaNadj=mid extinct genus of pseudosuchian originally thought to be the ancestor to carnosaurian dinosaurs, but now known to be more closely related to crocodilians than to dinosaurs.
TriassicLossiemouth, Spynie, and Findrassie ScotlandA quadrupedal armoured aetosaur, around 2 m long, with a very small head for its size (25 cm). It had a beak-like face that arched upwards, and is believed to have used this to uproot plants in a similar manner to a modern pig. The peg-like molar teeth would have been suitable for chewing tough vegetation.
TriassicLossiemouth, ScotlandThis small cursorial archosaur (18 cm long) is of uncertain phylogenetic position. It is possibly the basal-most ornithodiran, the sister-taxon to Pterosauria, or a basal member of Avemetatarsalia that lies outside of Ornithodira.
TriassicLossiemouth, ScotlandA pseudosuchian, its phylogenetic position is debated.
  • Saltopus
    • S. elginensis Newton, 1894
TriassicLossiemouth, ScotlandWas thought to be Scotland's earliest dinosaur, but research by Professor M. Benton instead identified it as dinosauriform – a forerunner of the dinosaurs.

†Dicynodonts

Elgin Reptiles: Dicynodonts
TaxaPresenceLocationDescriptionImages
PermianCutties Hillock, ScotlandAn extinct therapsid. It was formerly assigned to the wastebasket taxon Dicynodon as Dicynodon traquairi. Re-study of the specimen using CT-scanning has allowed this taxon to be more formally described and it was renamed Gordonia traquairi.
  • Geikia
    • G. elginensis Newton, 1893
PermianCutties Hillock, ScotlandAn extinct therapsid notable for its unusual square-shaped skull.

†Pareiasaurs

Notes and References

  1. Benton . Michael J. . Walker . Alick D. . Saltopus, a dinosauriform from the Upper Triassic of Scotland . Earth and Environmental Science Transactions of the Royal Society of Edinburgh . 2011 . 101 . 3–4 . 285–299 . 10.1017/S1755691011020081. 129803084 .
  2. XIII. Reptiles from the Elgin sandstone.—Description of two new genera. E. T.. Newton. F. R.. S. 1 January 1894. Phil. Trans. R. Soc. Lond. B. 185. 573–607. rstb.royalsocietypublishing.org. 10.1098/rstb.1894.0013. free.
  3. Web site: Fossils. 10 December 2013.
  4. Clark. Neil D. L. . 2008. The Elgin Marvels. Deposits. 13. 36–39.
  5. Web site: Moray Firth Learning Zone - Elgin Reptiles. morayfirth-partnership.org.
  6. Web site: Elgin Museum (@ElginMuseum) - Twitter. twitter.com.
  7. Web site: New Red Sandstone Supergroup. BGS Lexicon of Named Rock Units . British Geological Society.
  8. Friend, P. 2012 Scotland: Looking at Natural Landscapes. The New Naturalist Library.
  9. Walker AD. 1973. The age of the Cuttie's Hillock Sandstone (Permo-Triassic) of the Elgin Area. Scottish Journal of Geology 9:177-183.
  10. Web site: PalAlba: Preserving Scotland's Fossil Heritage. sites.google.com.