A new psammosteid (Agnatha, Heterostraci) from the Amata Regional Stage of the Main Devonian Field and morpho-histological types of discrete micromeric elements in the family Psammosteidae
| Autor: | S P Nilov, V N Glinskiy |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
010506 paleontology
Regional stage new species 010502 geochemistry & geophysics 01 natural sciences Devonian Paleontology Psammosteidae Late Devonian 0105 earth and related environmental sciences Water Science and Technology Agnatha biology Main Devonian Field lcsh:QE1-996.5 Morpho biology.organism_classification Field (geography) Psammosteida lcsh:Geology Amata Heterostraci General Earth and Planetary Sciences Geology |
| Zdroj: | Estonian Journal of Earth Sciences, Vol 66, Iss 2, Pp 59-76 (2017) |
| ISSN: | 1736-7557 1736-4728 |
| Popis: | In memory of an outstanding palaeoichthyologist Elga Mark-Kurik The range of diversity of psammosteids from the family Psammosteidae is still poorly known. Here a new species, Psammosteus ramosus sp. nov. Glinskiy, from the Amata Regional Stage of the Main Devonian Field is described. Its morphology, ornamentation, histology of exoskeletal plates, and micromeric elements are compared with those of other representatives of the family Psammosteidae. The comparison shows a close relationship of the new species with Psammosteus falcatus Obruchev, P. kiaeri Halstead Tarlo and P. pectinatus Obruchev, a group of species that is significantly different from other representatives of the genus Psammosteus and constitutes a separate evolutionary lineage. On the basis of morphological and histological features we here differentiate in the fields of tesserae of Psammosteidae the discrete micromeric elements of the ‘basic type’, known in Psammosteus bergi (Obruchev), P. levis Obruchev, P. livonicus Obruchev, P. maeandrinus Agassiz, P. megalopteryx (Trautschold), P. praecursor Obruchev and Karelosteus weberi Obruchev, and micromeric elements of the ‘progressive type’, known in Psammosteus falcatus, P. cf. kiaeri and P. ramosus sp. nov. Glinskiy. |
| Databáze: | OpenAIRE |
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