New finds of psammosteids (Heterostraci) in the Devonian of Estonia and Latvia.
Subclass Heterostraci. In Iskopaemye pozvonochnye Rossii i sopredel'nykh stran.
On the evolution of the psammosteids (Heterostraci).
The taxon was initially recognized as a suborder by Kiaer (1932), who named it the Cyathaspida and included it with the suborders Psammosteida and Pteraspida within the order Heterostraci. He included within this taxon heterostracans in which (1) the orbits are not surrounded by the dorsal shield but form semicircular notches in it, (2) the large oblong branchial plate situated between the dorsal and ventral plates is detached and (3) the dentine ridges forming the surface of the dermal skeleton are smooth and not crenulated as in the pteraspids.
4.8) showed in cladistic form (although without a cladistic analysis) as part of a phylogeny of the Heterostraci a simple cyathaspid phylogeny in which Nahanniaspis represented basal forms and Anglaspis and Torpedaspis more advanced forms, while the ctenaspids and amphiaspids formed a sister-group.
Within the Heterostraci only the Pteraspididae have been subjected to a cladistic analysis (Pernegre & Elliott 2008) until an analysis of the Cyathaspididae was published by Lundgren & Blom (2013).
Novye dannye po Karelosteus weberi Obruchev (Agnatha: Heterostraci) [New data on Karelosteus weberi Obruchev (Agnatha: Heterostraci)].
The tessellated pattern of the dermal armour in the Heterostraci. Journal of the Linnean Society of London, Zoology, 47, 45-54.
The classification and evolution of the Heterostraci. Acta Palaeontologica Polonica, 7, 249-290.
At first psammosteids sensu stricto (from Drepanaspis to Psammosteus) in the group Heterostraci were proposed to form the families Drepanaspidae and Psammosteidae (Traquair 1900; Brotzen 1936; Berg 1940; Obruchev 1941) or only the family Drepanaspidae (Stensio 1927), or only the family Psammosteidae (Woodward 1910; Gross 1937; Berg 1955).
A revision of Obruchevia (Psammosteida: Heterostraci) and a description of a new obrucheviid from the Late Devonian of the Canadian Arctic.
New finds of the psammosteids (Heterostraci) in the Devonian of Estonia and Latvia.
Aufbau des Panzers obersilurischer Heterostraci
and Osteostraci Norddeutschlands (Geschiebe) and Oesels.
New fords of psammosteids (Heterostraci) in the Devonian of Estonia and Latvia.
Distribution of vertebrate microremains in samples from the Karksi outcrop Vertebrate taxa Karksi Karksi Karksi 02-1 02-2 02-3 Heterostraci Tartuosteus maximus xxx x x (Psammosteida) Pycnosteus xxx xx xx tuberculatus Ganosteus stellatus x?