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Noun1.heterostracan - extinct jawless fish with the anterior part of the body covered with bony plates; of the Silurian and Devonian
agnathan, jawless fish, jawless vertebrate - eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms
Heterostraci, suborder Heterostraci - extinct group of armored jawless fishes or fish-like vertebrate; taxonomy is not clear
References in periodicals archive ?
Ray's heterostracan studies were a focus of the later stages of his career and indeed, at the time of his death, he had almost completed a major monograph on this topic--a true magnum opus--that will be published posthumously.
A similar model of skeletal development is also seen in a heterostracan Lepidaspis serrata Dineley & Loeffler, 1976: it possesses dentine ridges on the aspidin ridges, filled with aspidin trabeculae (Keating et al.
Pander in 1856, who described shields of the heterostracan Tolypelepis undulata, plates of the osteichthyan Lophosteus superbus and a number of jaw bones of acanthodians (Pander 1856).
perensae Marss, Nethertonodus laadjalaensis Marss, Trimerolepis tricava (Gross), Longodus acicularis Marss; heterostracan Archegonaspis sp.
A complete, articulated heterostracan from Wenlockian (Silurian) beds of the Delorme Group, Mackenzie Mountains, Northwest Territories, Canada.
In the incomplete Lower Devonian sequence the Phialaspis (previous Traquairaspis) heterostracan Zone and the Skamolepis fragilis thelodont Zone have been recognized.
early Devonian tessellated heterostracan Oniscolepis Pander, 1856 from the East Baltic and North Timan.
Psammosteid heterostracans (Pteraspidomorpha) predominate in number among species-level taxa, but the specimens of antiarch placoderm remains are most numerous.