Morphology and histology of dorsal spines of the xenacanthid shark Orthacanthus platypternus from the Lower Permian of Texas, USA: palaeobiological and palaeoenvironmental implications

Beck, Kimberly G.; Soler-Gijón, Rodrigo; Carlucci, Jesse R.; Willis, Ray E.

doi:10.4202/app.00126.2014

Cited by 6 publications

(9 citation statements)

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“…It suggests the genus was practising filial cannibalism of juvenile xenacanthids (as postulated at other sites; Hampe ; Soler‐Gijón ; Heidke ; Johnson ; Beck et al . ). The ecology of the other abundant shark, Ageleodus , remains completely unknown, and it is even uncertain whether skeletal elements represent teeth or specialized branchial denticles (Lebedev ; Turner ).…”

Section: Discussionmentioning

confidence: 97%

Fish and tetrapod communities across a marine to brackish salinity gradient in the Pennsylvanian (early Moscovian) Minto Formation of New Brunswick, Canada, and their palaeoecological and palaeogeographical implications

et al. 2016

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42The cosmopolitan biogeography of many fish genera strongly indicates marine-based 43 dispersal, while strontium isotopic data suggest these same fish were exposed, at times, to ). An intriguing characteristic of this episode was the apparent widespread adoption of 68 a euryhaline habit amongst organisms as diverse as microconchids, ostracodes, xiphosurans 69 and fish (Anderson and Shuster 2003; Carpenter et al. 2011; Bennett et al. 2012; Gierlowski-70 Kordesch and Cassle 2015). Euryhaline animals are relatively rare in modern ecosystems 71 (Edwards and Marshall 2013; McCormick et al. 2013), and their dominance in Carboniferous 72 times suggests marine communities converged on similar osmoregulatory strategies in order 73 to utilise empty non-marine coastal ecospace for feeding and breeding (Williams et al. 2006; 74 Carpenter et al. 2014), prior to the widespread colonisation of freshwater tracts further inland. 75The mid-Carboniferous diversification event coincided with a sharp growth of 76Gondwanan ice sheets and the onset of significant Milankovitch-driven glacio-eustatic 86Much recent attention has been given to the apparent dominance of a euryhaline mode 87 of life amongst mid-Carboniferous fish communities (Schultze 2009; Carpenter et al. 2011 Carpenter et al. , 88 2014Carpenter et al. , 2015. However, consensus regarding ecology is currently lacking, with some 89 researchers arguing on palaeogeographic, sedimentological and geochemical grounds that fish 90 taxa, especially xenacanthid sharks (Masson and Rust 1984), may have been obligate 91 freshwater organisms (Śtamberg and Zajíc 2008;Fischer et al. 2011 Fischer et al. , 2013 Montañez and 92 Cecil 2013). In this paper, we describe a new fish fauna from the Carboniferous 93 (Pennsylvanian) of New Brunswick, Canada (Fig. 1A), and demonstrate -based on 94 independent indicators of palaeo-salinity -that fish taxa existed across a brackish to marine 95 gradient, and that communities must therefore have been euryhaline. We discuss how these 96 new findings improve understanding of Carboniferous fish ecology and the mid- 97Carboniferous diversification of non-marine ecosystems in particular. The fish fossils reported here were obtained from opencast mine sites (now reclaimed) within 102 the Minto Coalfield, Queens County, New Brunswick, Canada (Fig. 1A-C 98 +REVISE FOR TETRAPOD STORY 123Extensive borehole arrays indicate that this basal unconformity is marked by a major silcrete 124 paleosol, up to 9 m thick in places (Sullivan 1981; St Peter 2000), which mantles the 125 basement complex and indicates seasonally-dry climate weathering over the preceding (Fig. 3A), implying that the basin deepened towards the 137 southwest, and sediment progressively onlapped towards the northeast; and (2) NE-SW- Coal, fine towards the southwest (Fig. 3B) and suggest sediment transport in that direction. 140We note, however, that this inferred palaeoflow direction opposes regional patterns of Geological Surveys Branch, Fredericton (Fig. 4A). 154The low...

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Section: Discussionmentioning

confidence: 97%

Fish and tetrapod communities across a marine to brackish salinity gradient in the Pennsylvanian (early Moscovian) Minto Formation of New Brunswick, Canada, and their palaeoecological and palaeogeographical implications

et al. 2016

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“…The innermost part of the spine, called the trunk, is made of inward and outward growing orthodentine (Maisey, 1979). Inward and outward growing trunk dentine similar to that from extant chondrichthyans is also described from the fossil dorsal spines of the xenacanth shark Orthacanthus (Soler-Gijón, 1999;Beck et al, 2016), hybodont sharks (Maisey, 1978), and Mesozoic holocephalans (Patterson, 1965, Jerve et al, 2014. However, many fossil taxa lack a dentine trunk and have a spine that is composed primarily of trabecular dentine, including some Helodus (Patterson, 1965), Sphenacanthus (Maisey, 1982), ctenacanth sharks (Maisey, 1982;Stamberg, 2001), and sinacanth spines (Coates et al, 1998;Maisey, 2009).…”

Section: Histological Compositions Of Ramsåsa Fin Spines -Comparison mentioning

confidence: 99%

“…In extinct chondrichthyans, the dorsal fin spines display a wide range of morphologies from the large spine-brush complex in symmoriiforms (Maisey, 2009), the tubiform spines of xenacanths (Soler-Gijón, 1999;Beck et al, 2016), to the typical selachian fin spines in ctenacanthoids and hybodontoids (Zangerl, 1981;Stamberg, 2001). The median dorsal spines from the Ramsåsa assemblage, which are represented by morphotypes D, E and G, are also symmetrical and recurved, but some are much more laterally compressed than what is seen in both extinct and extant chondrichthyan material.…”

Section: Morphological and Taxonomical Affinitiesmentioning

confidence: 99%

“…Callorhinchus fin spines are generally more ornamented than those from extant sharks, having some longitudinal striations near the anterior portion of the spine surface and retrose nodes along the posterolateral margins. Xenacanth sharks had spines ornamented with longitudinal striae on the anterior face and denticles on the posterior side of the tip (Soler-Gijón, 1999;Beck et al, 2016), while dorsal fin spines of ctenacanths and hybodontoids can be covered in enameloid tubercles or nodes and may bear posterolateral denticles (Cappetta, 1987). Acanthodian spines are generally much more ornamented with ribbing or nodes (Denison, 1979), which is observed on all of the Ramsåsa morphotypes.…”

Section: Histological Compositions Of Ramsåsa Fin Spines -Comparison mentioning

confidence: 99%

“…There are additional areas of growth in dorsal fin spines from all extant spine-bearing chondrichthyans and some fossil chondrichthyans (e.g., Orthacanthus), which is marked by the presence of trunk dentine exhibiting both outward and inward growth (Maisey, 1979;Soler-Gijon, 1999;Tovar-Ávila et al, 2008;Beck et al, 2016). Callorhinchus and other holocephalan fin spines also have a trabecular component (Halstead and Bunker, 1952;Jerve et al, 2014).…”

Section: Growth Patterns Of Ramsåsa Fin Spinescomparison With Fossil mentioning

confidence: 99%

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Morphology and histology of acanthodian fin spines from the late Silurian Ramsåsa E locality, Skåne, Swede

Jerve¹,

Bremer²,

Sanchez³

et al. 2017

Palaeontologia Electronica

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Systematics, ontogeny and palaeobiogeography of the genus Orthacanthus (Diplodoselachidae, Xenacanthiformes) from the lower Permian of France

Luccisano

Pradel

Amiot

et al. 2022

Papers in Palaeontology

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The erection of Orthacanthus buxieri Heyler & Poplin from the lower Permian locality of Buxi eres-les-Mines (Allier, France) was based on a poorly prepared specimen with only a few parts of its anatomy visible. The supposedly related teeth have been regarded as possibly belonging to O. kounoviensis, a species already known from the Carboniferous-Permian of Germany and Czech Republic. The holotype of O. buxieri requires extensive preparation before it can be revised, but the description of Orthacanthus isolated teeth and dorsal spines from Buxi eres-les-Mines nevertheless provides useful information, especially given that no precise description of this material has been provided so far. The aim of this description is to better understand the evolutionary history of the French Orthacanthus and its relationships with the other European species. The studied material is assigned to O. kounoviensis. This is the latest occurrence of this genus in Europe and the presence of both juvenile and adult teeth indicate that Buxi eres-les-Mines was probably one of the last suitable environments for its reproduction. We also identify Orthacanthus cf. kounoviensis from the Muse oil-shale bed, the first record of this genus in the Autun Basin. This brings into question the relationships between the different Carboniferous-Permian basins of the Northern Massif Central and suggests that they could still have been in connection during the lower Permian, in contrast to the central European basins, which seem to be more isolated from each other.

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Morphology and histology of dorsal spines of the xenacanthid shark Orthacanthus platypternus from the Lower Permian of Texas, USA: palaeobiological and palaeoenvironmental implications

Abstract: Detailed studies on Carboniferous species of the xenacanth

Cited by 6 publications

References 56 publications

Fish and tetrapod communities across a marine to brackish salinity gradient in the Pennsylvanian (early Moscovian) Minto Formation of New Brunswick, Canada, and their palaeoecological and palaeogeographical implications

Fish and tetrapod communities across a marine to brackish salinity gradient in the Pennsylvanian (early Moscovian) Minto Formation of New Brunswick, Canada, and their palaeoecological and palaeogeographical implications

Morphology and histology of acanthodian fin spines from the late Silurian Ramsåsa E locality, Skåne, Swede

Systematics, ontogeny and palaeobiogeography of the genus Orthacanthus (Diplodoselachidae, Xenacanthiformes) from the lower Permian of France

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