Hyperossification in the vertebral column of Devonian placoderm fishes (Arthrodira)
Journal of Vertebrate Paleontology, 2020 Skeletal bone enlargement (hyperossification) was thought to only occur in endochondral and dermal bones (e.g., endoskeletons of marine tetrapods and dermal bones of certain jawless vertebrates, placoderms, and teleost fishes). However, in some arthrodiran placoderms (basal jawed vertebrates), i.e., Millerosteus minor, Compagopiscis croucheri ...
van Mesdag, S. +3 more
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Paleo-evo-devo implications of a revised conceptualization of enameloids and enamels. [PDF]
Biol Rev Camb Philos SocABSTRACT Understanding the origin and evolution of the mineralized skeleton is crucial for unravelling vertebrate history. However, several limitations hamper our progress. The first obstacle is the lack of uniformity and clarity in the literature for the definition of the tissues of concern, especially of enameloid(s) and enamel(s), resulting in ...
Houée G +3 more
europepmc +2 more sources
Cautionary tales on the use of proxies to estimate body size and form of extinct animals. [PDF]
Ecol EvolReconstructing the body size and form of extinct animals is of vital importance to our understanding of macroevolution and palaeontology. This is often done using anatomical proxies where extinct species are known only from fragmentary remains. However, there are many limitations influencing the selection of proxy taxa that are frequently overlooked ...
Gayford JH +7 more
europepmc +2 more sources
Ecomorphological inferences in early vertebrates: reconstructing Dunkleosteus terrelli (Arthrodira, Placodermi) caudal fin from palaeoecological data [PDF]
PeerJ, 2017 Our knowledge about the body morphology of many extinct early vertebrates is very limited, especially in regard to their post-thoracic region. The prompt disarticulation of the dermo-skeletal elements due to taphonomic processes and the lack of a well ...
Humberto G. Ferrón +2 more
doaj +3 more sources
Placoderm fishes, pharyngeal denticles, and the vertebrate dentition
Journal of Morphology, 2003 AbstractThe correlation of the origin of teeth with jaws in vertebrate history has recently been challenged with an alternative to the canonical view of teeth deriving from separate skin denticles. This alternative proposes that organized denticle whorls on the pharyngeal (gill) arches in the fossil jawless fish Loganellia are precursors to tooth ...
Johanson, Z, Smith, M M
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Vascularization and odontode structure of a dorsal ridge spine of Romundina stellina Ørvig 1975. [PDF]
PLoS ONE, 2017 There are two types of dermal skeletons in jawed vertebrates: placoderms and osteichthyans carry large bony plates (macromery), whereas chondrichthyans and acanthodians are covered by small scales (micromery).
Anna Jerve +4 more
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Bioerosion in the Late Devonian placoderm remains from the Holy Cross Mountains, Poland
Acta Palaeontologica PolonicaWe report the first occurrence of trace fossils in placoderm bones from the Upper Devonian of the Holy Cross Mountains. A taxonomic analysis of three ichnogenera revealed the earliest evidence of Sulculites (ie., Sulculites bellus), characterised by ...
Patrycja G. Dworczak +2 more
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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
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Neurocranial anatomy of the petalichthyid placoderm <i>Shearsbyaspis oepiki</i> Young revealed by X-ray computed microtomography. [PDF]
Palaeontology, 2018 Stem‐group gnathostomes reveal the sequence of character acquisition in the origin of modern jawed vertebrates. The petalichthyids are placoderm‐grade stem‐group gnathostomes known from both isolated skeletal material and rarer articulated specimens of ...
Castiello M, Brazeau MD.
europepmc +2 more sources
The relationship of placoderms [PDF]
Journal of Vertebrate Paleontology, 1984 ABSTRACT A review of the evidence suggests that placoderms are more closely related to osteichthyans than chondrichthyans. A new phylogeny of placoderms is proposed in which the ptyctodonts are considered the collateral descendants of all other placoderms.
Long, J. +11 more
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