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The two most common fish in Achanarras are Coccosteus cuspidatus and Dipterus valenciennesi References: A Guide to Achanarras Fossils Volume 16: Fossil Fishes of Great Britain Chapter 6: Mid-Devonian fossil fishes sites of Scotland. Site: ACHANARRAS QUARRY (GCR ID: 351)

Grammatically incorrect form: Pentlandia macropterus. Taxonomy from Challands & Blaauwen, 2016. Emended diagnosis from Challands & Blaauwen, 2016, p. 3: "A medium-sized dipnoan (up to 40 cm) in which the I-bones do not meet medially posterior to the B-bone. The B-bone is 1.2 times as long as it is wide. The paired C-bones are 1.7 times long as they are wide. There are two paired Y-bones that lie lateral to the I-bone and contact the operculum along with bone 4, the J-bone, and the X-bone. Only one suboperculum is present. The X-bone carries the bifurcation for the supraorbital and infraorbital lateral line. There are six circumorbital bones, bone 3 being positioned dorsally and the largest. An A-bone is present posterior to the B-bone. The parasphenoid is short with a poorly developed posterior stalk. The entopterygoids are thin and L-shaped and carry subtriangular tooth plates with up to 12 rows of dentine-covered cusps. The lateral margins of the A-bone contact dorsal protuberances of the I-bone. The posterior dorsal fin is 17% of the total length of the animal with the anterior-most portion supported by a basal plate that carries three radials. Cosmine is not present on any scales or dermal bones. M-, O-, and P-bones are present in the snout region anterolateral to the E-bones but anterior to these bones the snout is unossified or poorly ossified and is not preserved in all but the largest specimens." Reconstruction from Challands & Blaauwen, 2016, p. 40: Identified by oilshale. References: Challands, T. and Blaauwen, Jan den (2016) A redescription of the Middle Devonian dipnoan Pentlandia macroptera Traquair, 1889, and an assessment of the Phaneropleuridae. Zoological Journal of the Linnean Society. p. 1-47. doi: 10.1111/zoj.12491 Volume 16: Fossil Fishes of Great Britain. Chapter 6: Mid-Devonian fossil fishes sites of Scotland. Site: JOHN O'GROATS, CAITHNESS (GCR ID: 353) Emma Jude, Zerina Johanson, Anton Kearsley and Matt Friedman(2014): Early evolution of the lungfish pectoral-fin endoskeleton: evidence from the Middle Devonian (Givetian) Pentlandia macroptera. Frontiers in Earth Science, 2014, Vol. 2, Article 18

The little fish, Palaeospondylus gunni, from the Middle Devonian of Achanarras, Caithness, is perhaps the most widely known of all problematical fossils. Ever since it was first described by Traquair in 1890, it has attracted the attention of a very large number of workers. Nevertheless, its affinities have not yet been convincingly demonstrated. The phylogeny of this bizarre fossil has puzzled scientists since its discovery in 1890, and many taxonomies have been suggested. Traquair and the majority of writers have considered Palaeospondylus to be related to Cyclostomes. However, other workers proposed that Palaeospondylus was a larval lungfish, a larval tetrapod, an unarmored placoderm, an agnathan or a chimera. In 2016, Tatsuya Hirasawa, Yasuhiro Oisi and Shigeru Kuratani proposed that Palaeospondylus was a primitive hagfish. This assignment was recently questionend by Z. Johanson et al.: X-ray tomography provided new data and morphological characters demonstrating that Palaeospondylus is a jawed vertebrate. Line drawing: References: J. A. Moy-Thomas (1940): The Devonian Fish Palaeospondylus gunni Traquair. Philosphical Transactions of the Royal Society B. 1940, Volume 230, issue 573. Tatsuya Hirasawa, Yasuhiro Oisi and Shigeru Kuratani (2016): Palaeospondylus as a primitive hagfish. Zoological Letters 2016, 2:20. Volume 16: Fossil Fishes of Great Britain Chapter 6: Mid-Devonian fossil fishes sites of Scotland. Site: ACHANARRAS QUARRY (GCR ID: 351) Johanson Z, Smith M,Sanchez S, Senden T, Trinajstic K, Pfaff C. 2017 Questioning hagfish affinities of the enigmatic Devonian vertebrate Palaeospondylus. R. Soc. open sci. 4: 170214. http://dx.doi.org/10.1098/rsos.170214. Achanarras Quarry

References: Volume 16: Fossil Fishes of Great Britain. Chapter 6: Mid-Devonian fossil fishes sites of Scotland. Site: JOHN O'GROATS, CAITHNESS (GCR ID: 353) Long, J.: Origins of copulation - ancient Scottish fishes did it sideways, square-dance style.