Silurian-Devonian vertebrate-dominated communities, with particular reference to agnathans
. In Paleocommunities: a case study from the Silurian and Lower Devonian.
As noted above, there are two copies of Aqp3 in the agnathan
lamprey genome (sea lamprey Petromyzon marinus Linnaeus, 1758; Finn et al., 2014) but the amino acid homology of these sequences is only 34.2%.
Novitskaya (2004) reviewed fossil 'agnathans
and early fishes' of the former USSR and treated the cyathaspids as an order, Cyathaspidiformes, as Obruchev (1964; order Cyathaspidida) had done previously.
Antigen-receptor genes of the agnathan
lamprey are assembled by a process involving copy choice.
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.
Lampreys are jawless vertebrates (agnathans
) and the most primitive representatives of the cyclostome branch from which it is feasible to obtain embryos routinely.
Some marl levels downstream along the Lemovzha River contain well-preserved remains of agnathans
and fishes (Ivanov & Lebedev 2011; Skutschas et al.
The taxonomy and distribution of agnathans
and fishes in southern Britain have been investigated, the regional vertebrate zonal scheme has been updated and characteristic vertebrate assemblages have been correlated with the conodont zonation (Miller & Marss 1999; Turner 2000; Marss & Miller 2004).
The fossil fishes that have so far been used for distinguishing zones are agnathans
, placoderms and acanthodians (e.g.
A new agnathan
from the Lower Devonian of Arctic Canada, and a review of the tessellated heterostracans.
Kompleksy srednedevonskikh psammosteidnykh beschelyustnykh vostochnoj chasti Glavnogo devonskogo polya [The assemblages of Middle Devonian psammosteid agnathans
from the eastern part of Main Devonian Field].
Three distinctive assemblages of agnathans
are recognized in the Riksu and Rootsikula formations (Wenlock) and in the Paadla Formation (Ludlow).