X-ray micro-computed tomography (micro-CT) of pyrite-permineralized fruits and seeds from the London Clay Formation (Ypresian) conserved in silicone oil: a critical evaluation

Collinson, Margaret E.; Adams, Neil F.; Manchester, Steven R.; Stull, Gregory W.; Herrera, Fabiany; Smith, Selena Y.; Andrew, Mary J.; Kenrick, Paul; Sykes, Dan

doi:10.1139/cjb-2016-0078

Cited by 36 publications

(18 citation statements)

References 61 publications

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“…In order to accurately reconstruct the three-dimensional (3D) morphology of Viracarpon and non-destructively study valuable museum specimens, many of the fossils were studied using μCT ( Smith et al, 2009 ; Collinson et al, 2012 , 2016 ). In a μCT scan, X-rays are emitted by a microfocus X-ray tube and pass through a rotating sample to an X-ray detector, which takes a series of two-dimensional (2D) radiographic projection images as the sample rotates.…”

Section: Methodsmentioning

confidence: 99%

Reinvestigating an enigmatic Late Cretaceous monocot: morphology, taxonomy, and biogeography of Viracarpon

Matsunaga

Smith

Manchester

et al. 2018

PeerJ

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Angiosperm-dominated floras of the Late Cretaceous are essential for understanding the evolutionary, ecological, and geographic radiation of flowering plants. The Late Cretaceous–early Paleogene Deccan Intertrappean Beds of India contain angiosperm-dominated plant fossil assemblages known from multiple localities in central India. Numerous monocots have been documented from these assemblages, providing a window into an important but poorly understood time in their diversification. One component of the Deccan monocot diversity is the genus Viracarpon, known from anatomically preserved infructescences. Viracarpon was first collected over a century ago and has been the subject of numerous studies. However, resolution of its three-dimensional (3D) morphology and anatomy, as well as its taxonomic affinities, has remained elusive. In this study we investigated the morphology and taxonomy of genus Viracarpon, combining traditional paleobotanical techniques and X-ray micro-computed tomography (μCT). Re-examination of type and figured specimens, 3D reconstructions of fruits, and characterization of structures in multiple planes of section using μCT data allowed us to resolve conflicting interpretations of fruit morphology and identify additional characters useful in refining potential taxonomic affinities. Among the four Viracarpon species previously recognized, we consider two to be valid (Viracarpon hexaspermum and Viracarpon elongatum), and the other two to be synonyms of these. Furthermore, we found that permineralized infructescences of Coahuilocarpon phytolaccoides from the late Campanian of Mexico correspond closely in morphology to V. hexaspermum. We argue that Viracarpon and Coahuilocarpon are congeneric and provide the new combination, Viracarpon phytolaccoides (Cevallos-Ferriz, Estrada-Ruiz & Perez-Hernandez) Matsunaga, S.Y. Smith, & Manchester comb. nov. The significant geographic disjunction between these two occurrences indicates that the genus Viracarpon was widespread and may be present in other Late Cretaceous assemblages. Viracarpon exhibits character combinations not present in any extant taxa and its affinities remain unresolved, possibly representing an extinct member of Alismatales. The character mosaic observed in Viracarpon and the broad distribution of the genus provide new data relevant to understanding early monocot evolution and suggest that the (thus far) largely invisible Late Cretaceous monocot diversification was characterized by enigmatic and/or stem taxa.

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Section: Methodsmentioning

confidence: 99%

Reinvestigating an enigmatic Late Cretaceous monocot: morphology, taxonomy, and biogeography of Viracarpon

Matsunaga

Smith

Manchester

et al. 2018

PeerJ

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“…Type locality and horizon. Walton-on-the-Naze, Essex, United Kingdom; Walton Member of the London Clay Formation (previously Division A2; Jolley 1996; Aldiss 2012), early Eocene (early Ypresian; 54.6-55 million years ago; Collinson et al 2016).…”

Section: Diagnosismentioning

confidence: 99%

A partial skeleton of a new species of Tynskya Mayr, 2000 (Aves, Messelasturidae) from the London Clay highlights the osteological distinctness of a poorly known early Eocene “owl/parrot mosaic”

Mayr

2021

PalZ

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Tynskya eocaena is an early Eocene bird with a raptor-like skull and semi-zygodactyl feet, whose description is based on a skeleton from the North American Green River Formation. In the present study, three-dimensionally preserved bones of a new species of Tynskya, T. waltonensis, are reported from the London Clay of Walton-on-the-Naze (Essex, UK). The fossils belong to a single individual and provide new insights into the skeletal morphology of messelasturids. In particular, they reveal unusual vertebral specializations, with the cervical vertebrae having concave rather than saddle-shaped caudal articulation facets and the caudalmost thoracic vertebra being platycoelous (flat articular surfaces). The very deep mandible and a derived morphology of the ungual phalanges support a sister group relationship between Tynskya and the taxon Messelastur (Messelasturidae). Phylogenetic analyses of an emended data matrix did not conclusively resolve the higher-level affinities of messelasturids and the closely related halcyornithids, with both taxa sharing derived characters with only distantly related extant taxa (Accipitriformes, Strigiformes, Falconiformes, and Psittaciformes). An analysis that was constrained to a molecular scaffold, however, recovered messelasturids as the sister taxon of a clade including psittaciform and passeriform birds. The derived morphologies of the mandible and cervical vertebrae suggest specialized feeding adaptations of Tynskya, and messelasturids may have exploited a feeding niche, which is no longer available to extant birds.

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“…An asterisk indicates a specimen not figured here but figured in Collinson et al (2016; this volume). observed from the specimens in Appendix A2 or obtained from the literature (Howard 1942a,b;Sleumer 1971;Peng and Howard 2008).…”

Section: Significance Of Extinct Taxa-mentioning

confidence: 99%

Revision of Icacinaceae from the Early Eocene London Clay flora based on X-ray micro-CT1

Stull¹,

Adams²,

Manchester³

et al. 2017

Preprint

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The Early Eocene (Ypresian) London Clay Formation contains one of the most important fruit and seed assemblages from the Paleogene, including a large diversity of taxa (>350 spp.) preserved as pyrite permineralizations retaining 3D structure as well as anatomical detail. Despite the importance of the flora for understanding angiosperm biogeographic and evolutionary history, the majority of the fossil material has not been revisited since the original taxonomic treatments by E.M. Reid and M.E.J. Chandler. Given subsequent advances in our understanding of angiosperm phylogeny and fruit morphology, coupled with technological advances in imaging/visualizing fossil material, many of the taxa represented in the flora deserve further study. Here we present a revision of the pantropical family Icacinaceae using X-ray micro-computed tomography (micro-CT) images of 21 species from the flora. Based on the results, four new combinations are made, a new fossil-genus is established for a distinctive species with affinities to the Phytocreneae, and emended diagnoses are provided for eight taxa. Of the seven genera recognized from the flora, only one, Iodes Blume, is extant. This study offers important insights on the biogeographic and evolutionary history of Icacinaceae, which is one of the most abundant and diverse components of the flora from the London Clay Formation.

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X-ray micro-computed tomography (micro-CT) of pyrite-permineralized fruits and seeds from the London Clay Formation (Ypresian) conserved in silicone oil: a critical evaluation

Cited by 36 publications

References 61 publications

Reinvestigating an enigmatic Late Cretaceous monocot: morphology, taxonomy, and biogeography of Viracarpon

Reinvestigating an enigmatic Late Cretaceous monocot: morphology, taxonomy, and biogeography of Viracarpon

A partial skeleton of a new species of Tynskya Mayr, 2000 (Aves, Messelasturidae) from the London Clay highlights the osteological distinctness of a poorly known early Eocene “owl/parrot mosaic”

Revision of Icacinaceae from the Early Eocene London Clay flora based on X-ray micro-CT1

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