Burrowing trilobite caught in the act

Fatka, Oldřich; Szabad, Michal

doi:10.1007/s12542-011-0102-4

Cited by 9 publications

(6 citation statements)

References 19 publications

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“…Reference to the enlarged photographs of topotype hypostomes CAMSM X11474 (Fig. P) and ÚÚG MŠ 267 by Fatka & Szabad () further demonstrates severe discrepancies in all previous interpretations of the unusual hypostomal lateral border, in particular, their placings of the lateral furrow. The hypostome border mainly comprises an interiorly directed, forked, posteriorly‐fused, pair of animal bone‐like structures raised above the depressed posterior lobe; note that the tips of the anterior wings are damaged and it is not possible to know from available specimens whether the ends are rounded or spinal.…”

Section: Systematic Palaeontologymentioning

confidence: 79%

“…Other, more recent examples are those hypostomes figured by Whittington (, pl. 55, figs 8, 9) and Fatka & Szabad (, fig. 3b) that form the basis of their incorrect drawn figures (Fig.…”

Section: Systematic Palaeontologymentioning

confidence: 94%

“…R), Whittington (; Fig. S) and Fatka & Szabad (; Fig. Q) are unreliable, because the area of the anterior margin of the hypostome is not exposed in any of the three known specimens due to damage.…”

Section: Systematic Palaeontologymentioning

confidence: 99%

“…13A), cephalon; E, Henningsmoen (, fig. 205.1), exoskeleton; H, Fatka & Szabad (, fig. 3a), dorsal side of a cephalon; M, Barrande (, pl.…”

Section: Systematic Palaeontologyunclassified

“…P, hypostome CAMSM X11474. Q–S, inaccurate interpretive drawings: Q, Fatka & Szabad () hypostome (h)‐rostral plate (r) relationship in Barrande's specimen ÚÚG MŠ 267; R, Barrande (, pl. 10, fig.…”

Section: Systematic Palaeontologymentioning

confidence: 99%

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Agraulos ceticephalusand other Cambrian trilobites in the subfamily Agraulinae from Bohemia, Newfoundland and Wales

Fletcher

2017

Papers in Palaeontology

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The Cambrian trilobite Agraulos ceticephalus Barrande, first described from Bohemia, is the type species for the genus and subfamily Agraulinae. That subfamily is here regarded as a ptychoparioid grouping in the family Solenopleuridae, characterized by prominently punctate cephala. In Bohemia, it occurs with, and is related to, specimens of the genus Skreiaspis Růžička, differing mainly in their glabellar shapes and cephalic borders. More‐complete descriptions of their type species are based largely on undistorted museum topotypes and supplementary specimens of ceticephalus collected from Avalonian Newfoundland and Wales. With such information and the use of Photoshop, a reinterpretation of the original tectonically‐distorted syntypes of ‘A. longicephalus’ from Wales indicates that those specimens cannot be differentiated from ceticephalus. Consequently, Hicks’ species may be regarded as a junior synonym. Additional information derived from recent Welsh collections concerns the hypostome–rostral plate relationship of ceticephalus and the recognition of a ventral plate lying beneath the rostral plate. Non‐syntype Welsh material, subsequently assigned to ‘longicephalus’, includes specimens of A. lewisi sp. nov. with a prominent occipital spine, relatively long genal spines and upstanding thoracic axial spines. Other species of Agraulos occur in Newfoundland, viz., affinis, socialis, ‘sp. nov. 1’ and ‘sp. nov. 2’, marked by differences in their anterior cephalic borders, occipital rings and ornamented thoracic axes. Two species of Skreiaspis, viz., punctatissimus sp. nov and ‘S. sp. nov. 1’ are recognized in the Newfoundland succession along with two other agraulines, Skehanos quadrangularis Whitfield and ‘Agraulinae gen. nov.’ To demonstrate the significant differences between the biometrics of the external surfaces and their inner parietal moulds/casts, and those of meraspid–holaspid cranidial growth stages between 0.10 and 2.9 cm sagittal length, a suite of A. socialis cranidia intermixed with some other Newfoundland agraulines of comparable size is illustrated.

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Section: Systematic Palaeontologymentioning

confidence: 79%

“…Other, more recent examples are those hypostomes figured by Whittington (, pl. 55, figs 8, 9) and Fatka & Szabad (, fig. 3b) that form the basis of their incorrect drawn figures (Fig.…”

Section: Systematic Palaeontologymentioning

confidence: 94%

Section: Systematic Palaeontologymentioning

confidence: 99%

“…13A), cephalon; E, Henningsmoen (, fig. 205.1), exoskeleton; H, Fatka & Szabad (, fig. 3a), dorsal side of a cephalon; M, Barrande (, pl.…”

Section: Systematic Palaeontologyunclassified

Section: Systematic Palaeontologymentioning

confidence: 99%

See 3 more Smart Citations

Agraulos ceticephalusand other Cambrian trilobites in the subfamily Agraulinae from Bohemia, Newfoundland and Wales

Fletcher

2017

Papers in Palaeontology

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The first report of the bivalved arthropod Tuzoia from the Skryje–Týřovice Basin (Barrandian area, Czech Republic)

Fatka

Herynk²

2016

Annales de Paléontologie

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Distinct causes underlie double-peaked trilobite morphological disparity in cephalic shape

Drage,

Pates

2024

Commun Biol

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Trilobite cephalic shape disparity varied through geological time and was integral to their ecological niche diversity, and so is widely used for taxonomic assignments. To fully appreciate trilobite cephalic evolution, we must understand how this disparity varies and the factors responsible. We explore trilobite cephalic disparity using a dataset of 983 cephalon outlines of c. 520 species, analysing the associations between cephalic morphometry and taxonomic assignment and geological Period. Elliptical Fourier transformation visualised as a Principal Components Analysis suggests significant differences in morphospace occupation and in disparity measures between the groups. Cephalic shape disparity peaks in the Ordovician and Devonian. The Cambrian–Ordovician expansion of morphospace occupation reflects radiations to new niches, with all trilobite orders established by the late Ordovician. In comparison, the Silurian–Devonian expansion seems solely a result of within-niche diversification. Linear Discriminant Analyses cross-validation, average cephalon shapes, and centroid distances demonstrate that, except for Harpida and the Cambrian and Ordovician Periods, order and geological Period cannot be robustly predicted for an unknown trilobite. Further, k-means clustering analyses suggest the total dataset naturally subdivides into only seven groups that do not correspond with taxonomy, though k-means clusters do decrease in number through the Palaeozoic, aligning with findings of decreasing disparity.

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Burrowing trilobite caught in the act

Cited by 9 publications

References 19 publications

Agraulos ceticephalusand other Cambrian trilobites in the subfamily Agraulinae from Bohemia, Newfoundland and Wales

Agraulos ceticephalusand other Cambrian trilobites in the subfamily Agraulinae from Bohemia, Newfoundland and Wales

The first report of the bivalved arthropod Tuzoia from the Skryje–Týřovice Basin (Barrandian area, Czech Republic)

Distinct causes underlie double-peaked trilobite morphological disparity in cephalic shape

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