New data on psammosteid heterostracans (Pteraspidomorpha) and acanthodians (Acanthodii) from the Pärnu Regional Stage (Lower Eifelian, Middle Devonian) of Estonia

Estonian Journal of Earth Sciences

Darya V. Pinakhina¹  Vadim N. Glinskiy² 

[1] [e-mail];Department of Sedimentary Geology, St Petersburg State University, 7/9 Universitetskaya nab., 199034 St Petersburg, Russia;

关键词: Agnatha;    Psammosteida;    Gnathostomata;    Acanthodii;    Middle Devonian;    Main Devonian Field;    histology.;   

DOI  :  10.3176/earth.2018.05

来源: DOAJ

【 摘 要 】

Vertebrate remains from the Lower Eifelian Pärnu Formation, Estonia, are described. New data on the topography of ornamentation and histology of psammosteids from the Pärnu Regional Stage are presented. The occurrence of the genus Guerichosteus Halstead Tarlo in the Lower Eifelian of the Main Devonian Field is established. Representatives of this taxon had previously been known from the Emsian (Lower Devonian) of the Holy Cross Mountains, Poland. The histological study of the exoskeleton of Guerichosteus heterolepis (Preobrazhensky) showed the presence of a thin layer of hypermineralized tissue (enameloid) on the surface of dentine tubercles. The taxonomic composition of the vertebrate assemblage from the Taali locality (Tori Parish, Pärnu County, southwestern Estonia) is described for the first time. Along with the taxa characteristic of the Pärnu Regional Stage, the acanthodian Cheiracanthus sp. cf. C. splendens is first recorded in this interval.

【 授权许可】

Unknown