DOI: 10.1016/j.palaeo.2016.12.012
论文题名: Skeletal microstructure of uintacrinoid crinoids and inferences about their mode of life
作者: Gorzelak P. ; Głuchowski E. ; Brachaniec T. ; Łukowiak M. ; Salamon M.A.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2017
卷: 468 起始页码: 200
结束页码: 207
语种: 英语
英文关键词: Cretaceous
; Crinoidea
; Santonian
; Stereom
英文摘要: Uintacrinoids (Uintacrinoidea) are among the most bizarre of all the crinoids. These stratigraphically important Late Cretaceous crinoids are characterized by an atypical large stalkless globular cup without cirriferous centrodorsal and extremely long arms. Owing to this unusual morphology, the mode of life of these crinoids has confused palaeontologists for more than a century. While uintacrinoids have been commonly regarded as pelagic forms, either swimming actively or floating passively by means of a putative buoyancy mechanism, some recent authors have favoured a benthic mode of life. However, evidence supporting a benthic lifestyle hypothesis is still limited. Here we describe the stereom microstructure of Marsupites and Uintacrinus. In Marsupites, thecal plates are typically comprised of coarse to medium, clearly structural, galleried stereom, which alternates with zones of fine and deeply penetrating galleried stereom oriented perpendicular to the plate margins. The latter stereom type corresponds to the external ribbed ornament of the theca, and is indicative of collagenous sutural fibers for binding adjacent plates. In Uintacrinus, thecal plates are almost entirely composed of fine galleried stereom diagnostic for collagenous sutural fibers. In both taxa, a perforate stereom layer, that is known to increase plate strengthening and resistance to abrasion in some Recent echinoderms, is developed most externally, and also produces a characteristic interior growth banding pattern. No skeletal adaptations for maintaining buoyancy, such as skeletal lightening and hollow architecture, that are known to occur in nektonic and pseudoplanktonic crinoids, are observed. Instead, the stereom organization in uintacrinoids closely resembles those observed in Recent benthic crinoids. Our findings thus strongly support a benthic mode of life of uintacrinoids. Their widespread distribution within a short time interval can be best explained by having a very long-term planktonic larval stage as previously hypothesized by some authors. © 2016 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/67977
Appears in Collections: 过去全球变化的重建
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作者单位: Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, Warsaw, Poland; Department of Palaeontology and Stratigraphy, Faculty of Earth Sciences, University of Silesia, Będzińska 60, Sosnowiec, Poland; Department of Geochemistry, Mineralogy and Petrography, Faculty of Earth Sciences, University of Silesia, Będzińska 60, Sosnowiec, Poland
Recommended Citation:
Gorzelak P.,Głuchowski E.,Brachaniec T.,et al. Skeletal microstructure of uintacrinoid crinoids and inferences about their mode of life[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2017-01-01,468