reconstruction of Turrisaspis

Turrisaspis elektor
(groenlandaspid placoderm)

fossil of TurrisaspisArticulated trunk and head shields of Turrisaspis elektor. The trunk shield is rotated clockwise relative to the head shield. Specimen is about 5 cm long. Photo courtesy of Ted Daeschler, ANS.

A new species of groenlandaspid placoderms, Turrisaspis elektor, is one of the two most numerous fossil vertebrates at Red Hill. (The other abundant species, Limnomis delaneyi, is a ray-fin.) Turrisaspis is represented by numerous articulated and partially articulated specimens and over 200 isolated plates, Common in both the shallow channel margin and the floodplain pond facies, it reached a density of over 20 individuals per square meter in one bedding plane of the channel margin facies. This horizon, which also contains the articulated remains of an unidentified acanthodian and Limnomis, may represent a mass mortality caused by stranding in an ephemeral pool.

Turrisaspis elektor is smaller (about 20 cm in length) than a similar new Red Hill placoderm, Groenlandaspis pennsylvanica. It can readily be distinguished from its larger relative by its narrow and tall median dorsal plate (a dermal skeletal element that resembles the dorsal fins in more familiar fishes).

Turrisaspis and Groenlandaspis pennsylvanica are the only two members of the Groenlandaspidae found in the Catskill Formation. Other members of this widely distributed family are known from elsewhere in Euramerica (Belgium, Germany, Greenland and Ireland) and Gondwana (Antarctica, Australia Columbia, Iran, South Africa and Turkey). The earliest member of this family is known from the Early Devonian. The last member, Groenlandaspis seni, dates from either the uppermost Devonian or the early Tournaisian (lowermost Carboniferous).

Another placoderm, Phyllolepis, has also been collected from Red Hill. You can also learn More About Placoderms.

 scuplture of turrisaspis Sculptural reconstruction of Turrisaspis elektor by C. Fredrick Mullison.
Photo courtesy of Ted Daeschler, ANS.

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Long, J.A. 1995. The Rise of Fishes: 500 Million Years of Evolution. Baltimore and London: John Hopkins Univ. Press.
Scientific Papers:
Daeschler, A.C. Frumes and C.F. Mullison. 2003. "Groenlandaspid placoderm fishes from the Late Devonian of North America." Records of the Australian Mus. 55:45-60.
Image Credits:
The reconstruction of Turrisaspis is copyrighted © 2005, Dennis C. Murphy. (See Terms of Use.)

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