Morphology, phylogeny and taxonomy of osteolepiform fish

Borgen, Ulf J.; Nakrem, Hans Arne

doi:10.1002/9781119286448.ch1

Cited by 13 publications

(17 citation statements)

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“…Although we find a basic conservation of extraosseous replacement within early sarcopterygians our results also reveal previously unrecognized diversity in replacement processes both between tooth types, and between teeth and denticles. In the lingual maxillary and dentary rows of Eusthenopteron and Tiktaalik , and the anterior tooth row (ectopterygoid) of Onychodus , teeth were replaced in an almost alternating pattern similar to other onychodontiforms and osteolepiforms [19,20]. This alternating replacement within distinct rows, or fang pairs (in the case of Eusthenopteron and Tiktaalik ), was traditionally used to infer the presence of a dental lamina [5,37].…”

Section: Discussionmentioning

confidence: 99%

“…Specimens were obtained from the Natural History Museum, London, United Kingdom (NHM UK), Naturhistoriska Riksmuseet, Stockholm, Sweden (NRM), Nunavet Fossil Vertebrate collection (NUFV), Canadian Museum of Nature, Ottawa, Ontario, Canada (NMC); tomographic data were obtained from the Muséum National d'Histoire Naturelle, Paris, France (MNHN). Scan data of the following specimens were used: a left maxilla, left dentary, left ectopterygoid and parasymphyseal tooth whorl of Onychodus jandemarrai (NHMUK PV P63570, Frasnian, Gogo Formation, Western Australia) [18]; an anterior right dentary fragment of Eusthenopteron foordi (NRM-PAL P.35; Frasnian, Escuminac Formation, Miguasha National Park, Canada) [20,23,24]; a left anterior dentary fragment of Tiktaalik roseae (NUFV666; Frasnian, Fram Formation, Nunavut territory, Canada); and a coronoid 2 of Latimeria chalumnae (MNHN-ZA-AC-2012-26, caught in Domoni, Comores) [25].…”

Section: Methodsmentioning

confidence: 99%

“…Based on phylogenetic bracketing, basal sarcopterygians might be expected to replace their teeth extraosseously, with damaged teeth shed via basal resorption, as in modern coelacanths and stem-osteichthyans. This is supported by the distinctive replacement pits organized in an alternating pattern in osteolepiform and onychodontiform jaws [19,20]. However, it is also known that onychodontiforms and porolepiforms had parasymphyseal ‘tooth whorls’ with a potential rotational replacement mechanism, somewhat reminiscent of that in chondrichthyans [19,21,22].…”

Section: Introductionmentioning

confidence: 99%

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Tooth replacement in early sarcopterygians

et al. 2019

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Teeth were an important innovation in vertebrate evolution but basic aspects of early dental evolution remain poorly understood. Teeth differ from other odontode organs, like scales, in their organized, sequential pattern of replacement. However, tooth replacement patterns also vary between the major groups of jawed vertebrates. Although tooth replacement in stem-osteichthyans and extant species has been intensively studied it has been difficult to resolve scenarios for the evolution of osteichthyan tooth replacement because of a dearth of evidence from living and fossil sarcopterygian fishes. Here we provide new anatomical data informing patterns of tooth replacement in the Devonian sarcopterygian fishes Onychodus, Eusthenopteron and Tiktaalik and the living coelacanth Latimeria based on microfocus- and synchrotron radiation-based X-ray microtomography. Early sarcopterygians generated replacement teeth on the jaw surface in a pattern similar to stem-osteichthyans, with damaged teeth resorbed and replacement teeth developed on the surface of the bone. However, resorption grades and development of replacement teeth vary spatially and temporally within the jaw. Particularly in Onychodus, where teeth were also shed through anterior rotation and resorption of bone at the base of the parasymphyseal tooth whorl, with new teeth added posteriorly. As tooth whorls are also present in more stem-osteichthyans, and statodont tooth whorls are present among acanthodians (putative stem-chondrichthyans), rotational replacement of the anterior dentition may be a stem-osteichthyan character. Our results suggest a more complex evolutionary history of tooth replacement.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tooth replacement in early sarcopterygians

et al. 2019

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“…More specifically, Hay (1902) was the first to coin the term “Megalichthyidae”, after which Long (1985) suggested synapomorphies to define this particular “osteolepidid” clade, but the first full familial description was not provided until Young, Long & Ritchie (1992) . This was later revised by Fox et al (1995) , Borgen & Nakrem (2016) , and again most recently by Downs & Daeschler (2020) .…”

Section: Introductionmentioning

confidence: 98%

“…Aside from Cladarosymblema , there are several other genera commonly recognised within the Megalichthyidae: Megalichthys ( Agassiz, 1835 ) contains several species found in Devonian-Carboniferous deposits across North America ( Cope, 1882 ; Downs & Daeschler, 2020 ), Morocco ( Janvier & Martin, 1979 ), and the UK ( Thomson, 1964 ); Ectosteorhachis nitidus ( Cope, 1882 ) is known from the Lower Permian of the USA ( Thomson, 1964 ); Sengoerichthys ottoman —considered by some as the earliest megalichthyid—from the Frasnian of Turkey ( Janvier, Clément & Cloutier, 2007 ); Palatinichthys laticeps described from the Lower Permian of Germany ( Witzmann & Schoch, 2012 ); and the most recently described megalichthyid genus, Askerichthys heintzi, comes from the Late Carboniferous of Norway ( Borgen & Nakrem, 2016 ). However, Downs & Daeschler (2020) considered that the “unusual combinations of characters” in S. ottoman and P. laticeps precluded them from being megalichthyids.…”

Section: Introductionmentioning

confidence: 99%

A fresh look at Cladarosymblema narrienense, a tetrapodomorph fish (Sarcopterygii: Megalichthyidae) from the Carboniferous of Australia, illuminated via X-ray tomography

Clement

Cloutier

Lü

et al. 2021

PeerJ

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Background The megalichthyids are one of several clades of extinct tetrapodomorph fish that lived throughout the Devonian–Permian periods. They are advanced “osteolepidid-grade” fishes that lived in freshwater swamp and lake environments, with some taxa growing to very large sizes. They bear cosmine-covered bones and a large premaxillary tusk that lies lingually to a row of small teeth. Diagnosis of the family remains controversial with various authors revising it several times in recent works. There are fewer than 10 genera known globally, and only one member definitively identified from Gondwana. Cladarosymblema narrienense Fox et al. 1995 was described from the Lower Carboniferous Raymond Formation in Queensland, Australia, on the basis of several well-preserved specimens. Despite this detailed work, several aspects of its anatomy remain undescribed. Methods Two especially well-preserved 3D fossils of Cladarosymblema narrienense, including the holotype specimen, are scanned using synchrotron or micro-computed tomography (µCT), and 3D modelled using specialist segmentation and visualisation software. New anatomical detail, in particular internal anatomy, is revealed for the first time in this taxon. A novel phylogenetic matrix, adapted from other recent work on tetrapodomorphs, is used to clarify the interrelationships of the megalichthyids and confirm the phylogenetic position of C. narrienense. Results Never before seen morphological details of the palate, hyoid arch, basibranchial skeleton, pectoral girdle and axial skeleton are revealed and described. Several additional features are confirmed or updated from the original description. Moreover, the first full, virtual cranial endocast of any tetrapodomorph fish is presented and described, giving insight into the early neural adaptations in this group. Phylogenetic analysis confirms the monophyly of the Megalichthyidae with seven genera included (Askerichthys, Cladarosymblema, Ectosteorhachis, Mahalalepis, Megalichthys, Palatinichthys, and Sengoerichthys). The position of the megalichthyids as sister group to canowindrids, crownward of “osteolepidids” (e.g.,Osteolepis and Gogonasus), but below “tristichopterids” such as Eusthenopteron is confirmed, but our findings suggest further work is required to resolve megalichthyid interrelationships.

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New description and diagnosis ofHyneria lindae(Sarcopterygii, Tristichopteridae) from the Upper Devonian Catskill Formation in Pennsylvania, U.S.A.

Daeschler

Downs

2018

Journal of Vertebrate Paleontology

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Morphology, phylogeny and taxonomy of osteolepiform fish

Cited by 13 publications

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Tooth replacement in early sarcopterygians

Tooth replacement in early sarcopterygians

A fresh look at Cladarosymblema narrienense, a tetrapodomorph fish (Sarcopterygii: Megalichthyidae) from the Carboniferous of Australia, illuminated via X-ray tomography

New description and diagnosis ofHyneria lindae(Sarcopterygii, Tristichopteridae) from the Upper Devonian Catskill Formation in Pennsylvania, U.S.A.

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