Agnatha

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Agnatha

aquatic, jawless, fish-like vertebrates characterized by fewer than two pairs of limbs (fins). The group is often given the status of a subphylum to separate it from other vertebrates with jaws which are included in the subphylum Gnathostomata. The Agnatha includes lampreys, hagfish, and the fossil OSTRACODERMI.
References in periodicals archive ?
2016 (collecting the agnathan and fish remains from the Gauja and Amata deposits of the Baltic Region and comparison of vertebrate assemblages).
Among euryhaline fishes, most teleosts and petromyzontid agnathans (lampreys) are regulators, while chondrichthyans and the myxinoid agnathans (hagfishes) are conformers (see "Water Balance in Elasmobranchs" below).
Electrolocation has been documented among agnathans (Bodznick and Northcutt, 1981), amphibians (Himstedt et al.
In 1975 a palaeontological expedition from Gottingen and Cologne universities (Germany) visited Arctic Canada (Langenstrassen & Schultze 1996) and inter alia collected agnathans and gnathostomes in Lower Devonian localities on the northern part of Prince of Wales Island (Fig.
An incorrect name for it is Atla (Patten 1931), since that locality is situated about 5 km to the northwest of Himmiste-Kuigu and has not yielded articulated agnathans or their shields and scales.
Evolution of the brain developmental plan: insights from agnathans.
The branchial region in vertebrates, including agnathans, is occupied by cephalic neural-crest-derived mesenchymes divided into preotic and postotic cell populations by the otic vesicle.
These strata are rich in fossils, including macro- and microremains of agnathans and fishes, conodonts, diverse shelly fauna and associations of invertebrate microfossils, with intense bioturbation and Skolithos trace fossils (Nestor 1990; Vinn & Wilson 2013; Marss & Nestor 2014), altogether indicating shallowwater environment.