†<i>Tingitanius tenuimandibulus,</i>a new platyrhinid batoid from the Turonian (Cretaceous) of Morocco and the cretaceous radiation of the Platyrhinidae

Claeson, Kerin M.; Underwood, Charlie J.; Ward, David J.

doi:10.1080/02724634.2013.767266

Cited by 30 publications

(72 citation statements)

References 25 publications

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“…I chose to include Pristis as an outgroup because, in some morphologically driven hypotheses of elasmobranch relationships, Pristis is the sister taxon to all remaining batoids (e.g., Shirai, ). I chose to include Platyrhinoidis as an outgroup because platyrhinid‐guitarfishes (Platyrhinidae) or guitarfish‐like taxa (e.g., †Spathobatidae) appear earliest in the fossil record (Underwood, ; Claeson et al, ). In addition, the only molecular analysis to treat all major clades of batoids simultaneously places electric rays and platyrhinids as sister taxa (Aschliman et al, ).…”

Section: Methodsmentioning

confidence: 99%

The impacts of comparative anatomy of electric rays (Batoidea: Torpediniformes) on their systematic hypotheses

Claeson

2013

Journal of Morphology

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The Comparative anatomy of the 11 recognized genera within Torpediniformes is described, systematically categorized, and illustrated in a comprehensive photo-atlas. Data are compiled into a character matrix and cladistically analyzed using parsimony to test hypotheses about the previously recognized subfamilies, while reconstructing the possible evolutionary history of Torpediniformes. Results are consistent with the previous rank-based classifications, regardless of the parsimony criteria used to generate the phylogenetic hypothesis, with one notable exception: a monophyletic Narcininae was never recovered. Torpedinoidea (=Hypnos + Torpedo) is supported by the presence of long, slender, flexible jaw cartilages, absence of a large rostral fontanelle, presence of suprascapular antimeres that are each shorter than the scapular process of the scapulocoracoid, antorbital cartilages that articulate on the anterior aspect of the nasal capsules and absence of a frontoparietal fontanelle. Subfamilial names Hypninae and Torpedininae are redundant with the genus names Hypnos and Torpedo and are not adopted here. Narcinoidea (=nontorpedinoid torpediniforms) is supported by unambiguous character transformations to the presence of a divided lower lip, labial cartilages, laterolingually compressed palatoquadrates, bifurcated antorbital cartilages, a rostral fontanelle, ventrally projecting nasal capsules, a dorsal rim of the synarcual mouth posterior to occipital condyle, posteriorly positioned lateral stays, and obtuse anterior margins of lateral stays. Narkidae is supported by unambiguous character transformations to the presence of an uncovered eye that protrudes above dorsal surface, a shared rim between the spiracle and the eye, an anterior nasal turret that projects ventrally, a nasal curtain that covers the upper lip and dentition when the mouth is closed, tab-like prepelvic processes, a mesopterygium that is shorter than propterygium but longer than metapterygium, a slender median rostral cartilage, and a basibranchial cartilage with an anterior margin that is depressed medially and a posterior margin that tapers.

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Section: Methodsmentioning

confidence: 99%

The impacts of comparative anatomy of electric rays (Batoidea: Torpediniformes) on their systematic hypotheses

Claeson

2013

Journal of Morphology

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“…This aspect of the topology resembles that of Maisey (), except for the placement of Pristis . Finally, more recently, Claeson, Underwood & Ward () considered Sclerorhynchus and Spathobatis as two consecutive stem‐batoid groups, with Spathobatis as sister to crown batoids. Similarly, the systematic position of Ptychotrygon remains controversial, even at a subordinal (or upper) level (Cappetta, ; see also Underwood, ; Kriwet, Nunn & Klug, ).…”

Section: Discussionmentioning

confidence: 99%

New insights into the enameloid microstructure of batoid fishes (Chondrichthyes)

2016

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Chondrichthyan teeth are capped with a hypermineralized tissue known as enameloid. Its microstructure displays a hierarchical organization that has increased in structural complexity from a homogenous singlecrystallite enameloid (SCE) in early Chondricthyans to the complex multilayered enameloid found in modern sharks (consisting of bundles of crystallites arranged in intriguing patterns). Recent analyses of the enameloid microstructure in batoid fishes, focused on Myliobatiformes and fossil taxa, point to the presence of a bundled (or fibred) multilayered enameloid, a condition proposed as plesiomorphic for Batoidea. In this work, we provide further enameloid analysis for a selection of taxa covering the phylogeny of batoids. Our SEM analysis shows a superficial layer of SCE, where individualized crystallites are clearly discernable, capping the teeth in most of the species studied. A bundled double-layered enameloid was found only in a Rhinoidei, Rhina ancylostoma Bloch & Schneider, 1801. We conclude that the most widespread condition among extant batoids is a monolayer SCE lacking microstructural differentiation, probably plesiomorphic at least for crown batoidea. We suggest that the complex bundled enameloid present in other batoids is a convergent character that has appeared repeatedly during the evolution of batoids, probably as a mechanical adaptation towards moderate durophagous diets.

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“…Whilst application of this method in the study of post-Palaeozoic chondrichthyans is in its infancy, it has allowed the study of specimens that could not be readily prepared from the matrix (e.g. Lane 2010, Claeson et al 2013. Even though the direct application of this method to chondrichthyans may be more limited than in other vertebrate fossil groups, it has vast potential and allows additional information to be extracted from specimens (Fig.…”

Section: Maisey 2001mentioning

confidence: 99%

Development of understanding of the Mesozoic and Cenozoic chondrichthyan fossil record

Underwood

Ward²,

Guinot

2015

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Fossils of post-Palaeozoic sharks and rays are common and well known, and have been extensively studied. Early studies, especially the monographic works of Agassiz and Woodward, described species based on macroscopic remains of isolated teeth, fin spines and rostral 'teeth' as well as rare specimens of articulated skeletons and skulls. This material was obtained from a range of sources but especially from commercial collectors in Britain and mainland Europe. Additional research over subsequent decades also concentrated on large specimens, giving a very biased perception of the chondrichthyan record. The use of large scale bulk sampling in the latter part of the 20 th Century revealed a previously unknown wealth of small fossils, especially teeth, and vastly improved knowledge of ancient sharks and rays. Widening use of these techniques to obtain small specimens has let to a dramatic increase in the fossil taxa known. In addition, re-assessment of previously known taxa has allowed has allowed generic diversity of some clades to be appreciated. Detailed work on

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†Tingitanius tenuimandibulus,a new platyrhinid batoid from the Turonian (Cretaceous) of Morocco and the cretaceous radiation of the Platyrhinidae

Cited by 30 publications

References 25 publications

The impacts of comparative anatomy of electric rays (Batoidea: Torpediniformes) on their systematic hypotheses

The impacts of comparative anatomy of electric rays (Batoidea: Torpediniformes) on their systematic hypotheses

New insights into the enameloid microstructure of batoid fishes (Chondrichthyes)

Development of understanding of the Mesozoic and Cenozoic chondrichthyan fossil record

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