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.
Exoskeleton ultrasculpture of early agnathans
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 assemblages of psammosteid agnathans
from the Middle-Late Devonian of the Andoma Hill (Russia).
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.
Three distinctive assemblages of agnathans
are recognized in the Riksu and Rootsikula formations (Wenlock) and in the Paadla Formation (Ludlow).
hedei, remains of several thelodont and osteostracan agnathans
were found on both islands (Klubov et al.
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.