Results 11 to 20 of about 236 (131)
An antiarch placoderm shows that pelvic girdles arose at the root of jawed vertebrates [PDF]
Biology Letters, 2012 Almost all gnathostomes or jawed vertebrates (including osteichthyans, chondrichthyans, ‘acanthodians’ and most placoderms) possess paired pectoral and pelvic fins. To date, it has generally been believed that antiarch placoderms (extinct armoured jawed fishes from the Silurian–Devonian periods) lacked pelvic fins.
Min Zhu, Xiaobo Yu, Brian Choo
exaly +5 more sources
A new Early Devonian antiarch placoderm from Belarus, and the phylogeny of Asterolepidoidei [PDF]
Acta Palaeontologica Polonica, 2023 A new asterolepidoid antiarch, Sherbonaspis talimaae sp. nov., is described based on the disarticulated skeletal elements from several boreholes in Belarus, from the Lepel Beds of the Vitebsk Formation, which has been assigned to an Early Devonian, late ...
Dmitry P. Plax, Ervins Lukševičs
doaj +2 more sources
Revision of asterolepidoid antiarch remains from the Ogre Formation (Upper Devonian) of Latvia [PDF]
Estonian Journal of Earth Sciences, 2020 The Frasnian (Upper Devonian) antiarch Walterilepis speciosa was first described in 1933 (as Taeniolepis) on the basis of a single specimen. The newly collected material has allowed the head to be described in a more detail, especially the nuchal and ...
Ervīns Lukševičs
doaj +2 more sources
Revision of the Late Devonian ptyctodonts (Vertebrata, Placodermi) from southern Poland [PDF]
Estonian Journal of Earth SciencesNew studies on Frasnian ptyctodonts, including the revision of historic material in addition to the description of new material, have resulted in the detailed description of two species of Ptyctodus (Ptyctodus obliquus, Ptyctodus kielcensis), eight ...
Katarzyna Grygorczyk +2 more
doaj +3 more sources
The internal cranial anatomy of Romundina stellina Ørvig, 1975 (Vertebrata, Placodermi, Acanthothoraci) and the origin of jawed vertebrates-Anatomical atlas of a primitive gnathostome. [PDF]
PLoS One, 2017 Placoderms are considered as the first jawed vertebrates and constitute a paraphyletic group in the stem-gnathostome grade. The acanthothoracid placoderms are among the phylogenetically most basal and morphologically primitive gnathostomes, but their ...
Dupret V +3 more
europepmc +3 more sources
An examination of the Devonian fishes of Michigan. [PDF]
PeerJ, 2018 We surveyed the taxa, ecosystems, and localities of the Devonian fishes of Michigan to provide a framework for renewed study, to learn about the diversity and number of these fishes, and to investigate their connection to other North American faunas ...
Stack J, Sallan L.
europepmc +3 more sources
New findings in a 400 million-year-old Devonian placoderm shed light on jaw structure and function in basal gnathostomes. [PDF]
Sci Rep, 2017 Arthodire placoderms have been proposed as the sister group of Chinese 'maxillate' placoderms plus all the more crownward gnathostomes. These basal groups provide key information for understanding the early evolution of jaws.
Hu Y, Lu J, Young GC.
europepmc +3 more sources
Известия высших учебных заведений: Геология и разведка, 2015 The stratigraphic distribution of antiarch remains in the Middle-Upper Devonian of central, southern and east-south regions of East European Platform (EEP), western slope of South Urals and Siberia are analyzed.
S. V. Moloshnikov
doaj +2 more sources
Mathematical Problems in Engineering, Volume 2018, Issue 1, 2018., 2018 A composite structure, including concrete antiarches and bolts, was designed to control the floor heave. This semiclosed structure may reinforce the floor and the two bottom corners of the roadway. Then, based on some relative assumptions, we established a model for this structure.
Wenxiang Zheng +3 more
wiley +2 more sources
Copulation in antiarch placoderms and the origin of gnathostome internal fertilization [PDF]
Nature, 2014 Reproduction in jawed vertebrates (gnathostomes) involves either external or internal fertilization. It is commonly argued that internal fertilization can evolve from external, but not the reverse. Male copulatory claspers are present in certain placoderms, fossil jawed vertebrates retrieved as a paraphyletic segment of the gnathostome stem group in ...
Long, J. +11 more
openaire +4 more sources