Antiarchi

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Antiarchi

[‚an·tē′är‚kī]
(paleontology)
A division of highly specialized placoderms restricted to fresh-water sediments of the Middle and Upper Devonian.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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Microbrachius is a small antiarch genus first discovered in the Middle Devonian (Givetian) Orcadian Basin of Scotland.
From the earliest descriptions of Microbrachius it was known that it was an antiarch although a more precise understanding of its phylogeny was not possible until the detailed description of the dermal armour was made by Hemmings (1978).
Under the prestressing of the CFRP plates, the antiarch of the strengthened RC beam occurred, so that the concrete flexural cracks in the tension zone are substantially closed, and by contrast, a few reverse flexural cracks occurred at the compression zone.
The lowermost vertebrate-bearing layer (layers 7 and 8) yields rare isolated skeletal elements of the psammosteid Psammolepis sp., arthrodire Plourdosteus livonicus (Eastman), antiarch Asterolepis sp., acanthodian Haplacanthus sp., an unidentifiable dipnoan fish, as well as porolepiforms Glyptolepis sp.
Psammosteid heterostracans (Pteraspidomorpha) predominate in number among species-level taxa, but the specimens of antiarch placoderm remains are most numerous.
The Andreyevka-2 community including antiarch placoderms, acanthodians, chondrichthyans and osteichthyans, as well as tetrapods, has been discussed on repeated occasions by the first author of this paper (Lebedev 1986, 1992, 2013; Lebedev et al.
No chondrichthyans have been recorded in Draguny and no antiarchs, actinopterygians and tetrapods are known further to the east in Mikhailovskoye.
The MNI of Phyllolepis tolli and Devononchus tenuispinus (see Tables 2, 3) is only slightly smaller than that of the antiarch placoderms (Bothriolepis), whereas other taxa, constituted by Dunkleosteus, Chelyophorus and sarcopterygians, are represented by minor MNI, but the actual number of remains varies greatly from only one specimen of Dunkleosteus sp.
2011) and the antiarch placoderm Asterolepis ornata, demonstrating head shields with plates tightly connected long after disintegration of the trunk shield (Upeniece 1999).
These are represented by species of arthrodires Coccosteus, Watsonosteus and Plourdosteus and antiarchs Asterolepis and Bothriolepis.