The assemblages of the Middle Devonian psammosteid agnathans
from the eastern part of the Main Devonian Field.
Thelodont and other agnathan
distributions as tests of lower Palaeozoic continental reconstructions.
Earlier invertebrate species do not possess either gene, and thus these two aqp genes, which are derived from aqp4, likely originated in an agnathan
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.
* Novel molecular mechanisms of receptor diversification are beginning to be found in a variety of invertebrate phyla and agnathan
In middle Saaremaa, microlaminated argillaceous Eurypterus-dolostones or domerites contain often lingulid, eurypterid, and agnathan
remains (Uduvere-968 core, depth 3.0-6.0 m; Kuressaare-804 core, depth 22.0-25.7 m; Suurlahe-738 core, depth 17.5-22.5 m).
Isolation of Dlx and Emx gene cognates in an agnathan
species, Lampetra japonica, and their expression patterns during embryonic and larval development: conserved and diversified regulatory patterns of homeobox genes in vertebrate head evolution.
The diverse agnathan
and fish remains include the psammosteids Pycnosteus tuberculatus (Rohon), Pycnosteus sp., Ganosteus stellatus Rohon, Tartuosteus maximus Mark-Kurik, Psammolepis abavica Mark-Kurik and Psammosteus bergi (Obruchev); the placoderms Rhynchodus sp., Actinolepis magna Mark-Kurik, Homostius cf.
In Scotland, the associated faunal list includes the protochordate Ainiktozoon loganense Scourfield and the agnathan
Jamoytius kerwoodi White in addition to L.
Sostav i rasprostranenie beschelyustnykh i ryb v silurijskikh i devonskikh otlozheniyakh Latvii [Composition and distribution of agnathan
and vertebrate assemblages in the Silurian and Devonian deposits of Latvia].
zones include mainly these of the psammosteid heterostracans.
vertebrates from the Lower Silurian of Gotland, Sweden.
dentata and compare them with those of other tessellated agnathan
Thus, the growth-promoting and osmoregulatory properties of the single hormone remained unchanged in agnathans
. Further comparative and functional studies of GH and PRL will shed more light on the divergence and development of these structurally and functionally related hormones and their receptors.
Exoskeleton ultrasculpture of early agnathans