Skip to Main Content
GEOREF RECORD

Discovery of the arthrodire genus Actinolepis (class Placodermi) in the Middle Devonian of Scotland

Michael J. Newman and Nigel H. Trewin
Discovery of the arthrodire genus Actinolepis (class Placodermi) in the Middle Devonian of Scotland
Scottish Journal of Geology (2008) 44 (1): 83-88

Abstract

A single specimen of the placoderm Actinolepis found in the Middle Devonian (Eifelian) Achanarras fish bed of Achanarras Quarry, Caithness, is the first record of the genus in the Devonian of Scotland. The articulated specimen displays an external view of the dorsal armour. Two species of Actinolepis are known from the Middle Devonian of the Baltic: Actinolepis tuberculata and Actinolepis magna. This find strengthens the faunal connection between the Baltic area and northern Scotland in Eifelian and Givetian times, which is supported by other species common to both areas, such as the arthrodire Millerosteus minor. Both areas were connected, perhaps at different times, to the same marine area. The most likely connection is to the Rheic Ocean to the south, but another possible connection lies between Laurentia and Baltica to an ocean to the north. Migration of fish into the Old Red Sandstone continent was controlled by long-term climatic cycles. When lake basins overflowed at times of high runoff, fish could migrate to internal continental basins through river systems. During dryer and hotter periods lake basins became isolated and fish evolved in non-marine waters, isolated from marine conditions, possibly explaining the minor differences in fish species from widely separated basins.


ISSN: 0036-9276
EISSN: 2041-4951
Coden: SJGEAX
Serial Title: Scottish Journal of Geology
Serial Volume: 44
Serial Issue: 1
Title: Discovery of the arthrodire genus Actinolepis (class Placodermi) in the Middle Devonian of Scotland
Affiliation: Llanstadwell House, Church Road, Milford Haven, United Kingdom
Pages: 83-88
Published: 2008
Text Language: English
Publisher: Scottish Academic Press, Edinburgh, United Kingdom
References: 35
Accession Number: 2009-010066
Categories: Vertebrate paleontology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch map
N58°10'00" - N58°40'00", W03°49'60" - W03°00'00"
Secondary Affiliation: Kings College, GBR, United Kingdom
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom
Update Code: 200906
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal