Paleoecology of pelmatozoan attachment structures from a hardground surface in the middle Silurian Massie Formation, southeastern Indiana

Thomka, James R.; Brett, Carlton E.

doi:10.1016/j.palaeo.2014.12.001

Cited by 18 publications

(19 citation statements)

References 41 publications

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“…For example, taxa that are particularly susceptible to fouling by fine-grained sediments and/or unable to occupy soft substrates will occur primarily or exclusively in carbonate hardground facies, which are best developed during major transgressive intervals in mixed carbonate-siliciclastic systems (e.g., Thomka and Brett, 2015). Conversely, those taxa that are particularly tolerant of turbidity and/or readily able to occupy soft, shifting, or unstable substrata may be restricted to various siliciclastic facies.…”

Section: Assessing Temporal Trendsmentioning

confidence: 99%

The role of preservation on the quantification of morphology and patterns of disparity within Paleozoic echinoderms

Deline

Thomka

2017

J. Paleontol.

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Abstract.-The loss of information resulting from taphonomic degradation could represent a significant bias in the study of morphological diversity. This potential bias is even more concerning given the uneven effect of taphonomy across taxonomic groups, depositional facies, and stratigraphic successions and in response to secular changes through the Phanerozoic. The effect of taphonomic degradation is examined using character-based morphological data sets describing disparity in Paleozoic crinoids and blastozoans. Characters were sequentially excluded from the analyses following progressive taphonomic loss to determine how morphologic metrics, such as the relative distribution of taxa in morphospace and partial disparity, changed with increasing taphonomic alteration. Blastozoans showed very little change in these metrics with decreasing preservational quality, which is a result of characters that create distance in morphospace being recognizable in isolated plates. The opposite result is present in crinoids as the characters that are important in structuring the morphospace require intact modules (i.e., the calyx) to accurately assess. Temporal and stratigraphic trends produced encouraging results in that patterns could be largely recovered even with exaggerated taphonomic biases. However, certain parts of a stratigraphic sequence should be avoided and morphological outliers could potentially play a larger role through time, though both of these biases can be easily identified and avoided. The methods presented in this study provide a way to assess potential taphonomic biases in character-based studies of morphological diversity.

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Section: Assessing Temporal Trendsmentioning

confidence: 99%

The role of preservation on the quantification of morphology and patterns of disparity within Paleozoic echinoderms

Deline

Thomka

2017

J. Paleontol.

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“…Brett (pers. comm., 2014) has found similar forms in the Rochester Shale associated with the large camerate Periechocrinus Morris ; they are also found on hardgrounds in the Massie Formation (Thomka & Brett ).…”

Section: Morphometrics: Resultsmentioning

confidence: 92%

“…This growth also obscures the boundaries between adjacent ossicles. This pattern is apparently characteristic of forms living on muddy substrates, but not of those in carbonate environments, where the individual ossicles remain visible (Thomka & Brett ). Examination of broken edges of radicle ossicles shows that most are circular in cross‐section.…”

Section: Morphometrics: Resultsmentioning

confidence: 99%

“…These are by far the most common crinoid holdfasts of any kind in museum collections. Eucalyptocrinites holdfasts are also known from the Rochester Shale in New York and Ontario (Brett & Eckert ) and from the correlative Massie Formation in Ohio and Indiana (Thomka & Brett ). Undescribed dendritic holdfasts occur in a number of other Silurian localities in North America (Frest et al .…”

Section: Palaeontology Of Eucalyptocrinitesmentioning

confidence: 99%

“…Franzén ; Brett , ; Donovan et al . ; Thomka & Brett ). Research on specific genera is less common, with most of the attention on unusual forms such as scyphocrinitid ‘loboliths’ and Ancyrocrinus Hall (Ehrenberg ; Haude ; Ausich et al .…”

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confidence: 99%

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A radicle solution: morphology and biomechanics of the Eucalyptocrinites ‘root’ system

Plotnick

Ebey

Zinga

2016

LET

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Eucalyptocrinites is one the most common and familiar mid‐Palaeozoic crinoids and is the exemplar of a form with dendritic radicular holdfasts. American museums have hundreds of specimens of Eucalyptocrinites holdfasts from the Silurian Waldron Shale of Indiana and Kentucky, USA. The radix (‘root’) system of Eucalyptocrinites can be described as comprised of links (branches) that meet at nodes. Measured values include the x‐ and y‐coordinates of the nodes, the distances of the nodes from the stem, the angles between branches, branch length and branch width. Rose diagrams show clearly that the root systems are not isotropic but have preferred orientations. Branch angles are highly variable, but cluster around 60 degrees. Branch lengths and distal branch widths are relatively constant, but branch width increases variably towards the column. The branching pattern can be modelled as a self‐similar (‘fractal’) structure. Several specimens labelled as Eucalyptocrinites show a distinct fivefold symmetry without branching and very likely represent a different taxon. The Eucalyptocrinites radix system, along with the probably stiff dististele, most likely functioned as a rigid plate that resisted rotational forces due to currents acting on the crown. Upstream radicles experienced tension, whereas downstream roots were compressed. This force distribution may explain the observed anisotropies in radix morphology. The ‘roots’ of Eucalyptocrinites and other crinoids have long been compared with the root systems of plants. Although there are superficial similarities, there are fundamental differences.

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A radix sorting parallel algorithm suitable for graphic processing unit computing

Xiao

Guo

et al. 2020

Concurrency and Computation

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Radix sorting is an essential basic data processing operation in many computer fields. It has important practical significance to accelerate its performance through Graphic Processing Unit (GPU). The heterogeneous parallel computing technology attracts much attention and is widely applied for its effective computation efficiency and parallel real-time data processing capability. Taking advantage of the parallelism of GPU in numerical computation processing, a parallelization design method of the Binary_Least Significant Digit (LSD) first Radix Sorting (B_LSD_RS) algorithm based on Open Computing Language (OpenCL) is proposed. The radix sorting algorithm is divided into multiple kernel tasks, and the kernels are sequentially controlled by the event information transfer. The parallel algorithm is implemented and verified on the GPU + CPU heterogeneous platform. The experimental results show that compared with the performance of the B_LSD_RS sequential algorithm based on AMD Ryzen5 1600X CPU, B_LSD_RS parallel algorithm based on Open Multi-Processing (OpenMP) and B_LSD_RS parallel algorithm based on Compute Unified Device Architecture (CUDA), the B_LSD_RS parallel algorithm based on OpenCL obtained 28.86 times, 11.01 times and 2.14 times speedup in the NVIDIA GTX 1070 computing platform respectively, not only achieves high performance but also achieves performance portability among different GPU computing platforms.

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Paleoecology of pelmatozoan attachment structures from a hardground surface in the middle Silurian Massie Formation, southeastern Indiana

Cited by 18 publications

References 41 publications

The role of preservation on the quantification of morphology and patterns of disparity within Paleozoic echinoderms

The role of preservation on the quantification of morphology and patterns of disparity within Paleozoic echinoderms

A radicle solution: morphology and biomechanics of the Eucalyptocrinites ‘root’ system

A radix sorting parallel algorithm suitable for graphic processing unit computing

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