The exoskeleton of Ungulaspis and Ateleaspis (Osteostraci, Agnatha) from the Lower Devonian of Severnaya Zemlya, Russia
The fragments of osteostracan exoskeleton from the Lover Devonian Severnaya Zemlya Formation of the Severnaya Zemlya archipelago, viz., Ungulaspis arctoa AFANASSIEVA & KARATAJUTE-TALIMAA, 1998 and Ateleaspis sp., were studied. The structure of the exoskeleton of non-tremataspid osteostracans was...
Main Author: | |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Faculty of Geology University of Warsaw
2003
|
Subjects: | |
Online Access: | https://gq.pgi.gov.pl/agp/article/view/10328 |
id |
ftjgq:oai:geojournals.pgi.gov.pl:article/10328 |
---|---|
record_format |
openpolar |
spelling |
ftjgq:oai:geojournals.pgi.gov.pl:article/10328 2024-09-15T17:50:01+00:00 The exoskeleton of Ungulaspis and Ateleaspis (Osteostraci, Agnatha) from the Lower Devonian of Severnaya Zemlya, Russia Afanassieva, Olga B. 2003-06-01 application/pdf https://gq.pgi.gov.pl/agp/article/view/10328 eng eng Faculty of Geology University of Warsaw https://gq.pgi.gov.pl/agp/article/view/10328/8840 https://gq.pgi.gov.pl/agp/article/view/10328 Acta Geologica Polonica; Vol. 49 No. 2 (1999): Circum-Arctic Palaeozoic Vertebrates; 119-123 Acta Geologica Polonica; Tom 49 Nr 2 (1999): Circum-Arctic Palaeozoic Vertebrates; 119-123 Osteostraci Agnatha Lower Devonian Severnaya Zemlya info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 2003 ftjgq 2024-07-30T03:29:09Z The fragments of osteostracan exoskeleton from the Lover Devonian Severnaya Zemlya Formation of the Severnaya Zemlya archipelago, viz., Ungulaspis arctoa AFANASSIEVA & KARATAJUTE-TALIMAA, 1998 and Ateleaspis sp., were studied. The structure of the exoskeleton of non-tremataspid osteostracans was investigated by SEM for the first time. A reconstruction of the structure of the Ungulaspis arctoa exoskeleton is suggested. Because of the poorer preservation of the Ateleaspis sp., only preliminary observations on the thin structure of its exoskeleton could be made. The forms under investigation are characterized by a similar type of sculpture on the surface of the shied (small tubercles) and on the body scales (thin crests). Some similarities in the structure of their shield exoskeleton (the presence of distinctly expressed tesserae, the presence of radiating canals, the probable absence of perforated septa and pore fields) were indicated. Ungulaspis arctoa is remarkable in the possessing macromorphological features typical of both the Ateleaspis- and Scolenaspis-like osteostracans. This similarity in the structure of exoskeleton of the investigated forms provides additional evidence in support of the affinity of these groups of osteostracans and their possible origin from common ancestors. Article in Journal/Newspaper Arctic Severnaya Zemlya Geological Quarterly |
institution |
Open Polar |
collection |
Geological Quarterly |
op_collection_id |
ftjgq |
language |
English |
topic |
Osteostraci Agnatha Lower Devonian Severnaya Zemlya |
spellingShingle |
Osteostraci Agnatha Lower Devonian Severnaya Zemlya Afanassieva, Olga B. The exoskeleton of Ungulaspis and Ateleaspis (Osteostraci, Agnatha) from the Lower Devonian of Severnaya Zemlya, Russia |
topic_facet |
Osteostraci Agnatha Lower Devonian Severnaya Zemlya |
description |
The fragments of osteostracan exoskeleton from the Lover Devonian Severnaya Zemlya Formation of the Severnaya Zemlya archipelago, viz., Ungulaspis arctoa AFANASSIEVA & KARATAJUTE-TALIMAA, 1998 and Ateleaspis sp., were studied. The structure of the exoskeleton of non-tremataspid osteostracans was investigated by SEM for the first time. A reconstruction of the structure of the Ungulaspis arctoa exoskeleton is suggested. Because of the poorer preservation of the Ateleaspis sp., only preliminary observations on the thin structure of its exoskeleton could be made. The forms under investigation are characterized by a similar type of sculpture on the surface of the shied (small tubercles) and on the body scales (thin crests). Some similarities in the structure of their shield exoskeleton (the presence of distinctly expressed tesserae, the presence of radiating canals, the probable absence of perforated septa and pore fields) were indicated. Ungulaspis arctoa is remarkable in the possessing macromorphological features typical of both the Ateleaspis- and Scolenaspis-like osteostracans. This similarity in the structure of exoskeleton of the investigated forms provides additional evidence in support of the affinity of these groups of osteostracans and their possible origin from common ancestors. |
format |
Article in Journal/Newspaper |
author |
Afanassieva, Olga B. |
author_facet |
Afanassieva, Olga B. |
author_sort |
Afanassieva, Olga B. |
title |
The exoskeleton of Ungulaspis and Ateleaspis (Osteostraci, Agnatha) from the Lower Devonian of Severnaya Zemlya, Russia |
title_short |
The exoskeleton of Ungulaspis and Ateleaspis (Osteostraci, Agnatha) from the Lower Devonian of Severnaya Zemlya, Russia |
title_full |
The exoskeleton of Ungulaspis and Ateleaspis (Osteostraci, Agnatha) from the Lower Devonian of Severnaya Zemlya, Russia |
title_fullStr |
The exoskeleton of Ungulaspis and Ateleaspis (Osteostraci, Agnatha) from the Lower Devonian of Severnaya Zemlya, Russia |
title_full_unstemmed |
The exoskeleton of Ungulaspis and Ateleaspis (Osteostraci, Agnatha) from the Lower Devonian of Severnaya Zemlya, Russia |
title_sort |
exoskeleton of ungulaspis and ateleaspis (osteostraci, agnatha) from the lower devonian of severnaya zemlya, russia |
publisher |
Faculty of Geology University of Warsaw |
publishDate |
2003 |
url |
https://gq.pgi.gov.pl/agp/article/view/10328 |
genre |
Arctic Severnaya Zemlya |
genre_facet |
Arctic Severnaya Zemlya |
op_source |
Acta Geologica Polonica; Vol. 49 No. 2 (1999): Circum-Arctic Palaeozoic Vertebrates; 119-123 Acta Geologica Polonica; Tom 49 Nr 2 (1999): Circum-Arctic Palaeozoic Vertebrates; 119-123 |
op_relation |
https://gq.pgi.gov.pl/agp/article/view/10328/8840 https://gq.pgi.gov.pl/agp/article/view/10328 |
_version_ |
1810291868969205760 |