New look at Concavicaris woodfordi (Euarthropoda: Pancrustacea?) using micro-computed tomography

IF 2 4区地球科学 Q1 Earth and Planetary Sciences

Palaeontologia Electronica Pub Date : 2023-01-01 DOI:10.26879/1218

Thomas Laville, T. Hegna, M. Forel, S. Darroch, S. Charbonnier

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引用次数: 1

Abstract

Known from at least the Silurian to the Cretaceous, Thylacocephala is an enigmatic fossil euarthropod ingroup, often allied with Pancrustacea. Previous studies show that thylacocephalans are characterized by a folded protective shield, hypertrophied compound eyes, three pairs of raptorial appendages, a posterior trunk comprised of eight to 22 segments bearing appendages, and eight pairs of gills. Despite this knowledge of their anatomy, many questions remain, especially surrounding the anatomy of Paleozoic representatives. The Upper Devonian Woodford Shale (upper Famennian, Oklahoma, USA) has yielded several fossil euarthropods, including two species of Thylacocephala: Concavicaris elytroides and Concavicaris woodfordi. Here, we use micro-computed Xray tomography to re-explore the anatomy of the holotype of C. woodfordi, illustrating fine details of the shield structure, of the circulatory, digestive and reproductive systems, and of the appendages. A marginal fold of the shield as well as an inner layer are described for the first time in a thylacocephalan. Concavicaris woodfordi shares similarities with Concavicaris submarinus, another Famennian species, including the morphology of the shield and the internal anatomy. It also displays a similar organisation as Mesozoic taxa, such as Dollocaris ingens. All of this provides important information that will be crucial to reconstruct the evolution and the affinities of Thylacocephala. Thomas Laville. Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie-Paris (UMR7207), MNHN-Sorbonne Université-CNRS, Paris, France and Biogéosciences, UMR 6282CNRS, Université Bourgogne Franche-Comté, EPHE, Dijon, France. Corresponding author. thomas.laville@ecomail.fr Thomas A. Hegna. Department of Geology and Environmental Science, State University of New York at Fredonia, New York, USA thomas.hegna@fredonia.edu Marie-Béatrice Forel. Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie-Paris (UMR7207), MNHN-Sorbonne Université-CNRS, Paris, France. marie-beatrice.forel@mnhn.fr Simon Darroch. Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, LAVILLE ET AL.: NEW LOOK AT CONCAVICARIS WOODFORDI 2 Tennessee, USA. simon.a.darroch@vanderbilt.edu Sylvain Charbonnier. Muséum national d’Histoire naturelle, Centre de Recherche en Paléontologie-Paris (UMR7207), MNHN-Sorbonne Université-CNRS, Paris, France. sylvain.charbonnier@mnhn.fr

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利用微型计算机断层扫描技术对木蛙进行新的观察（真节肢动物门：Pancrustacea？）

至少从志留纪到白垩纪，Thylacocephala是一种神秘的真节肢动物化石，通常与Pancrustacea联系在一起。先前的研究表明，袋头类动物的特征是:折叠的保护罩、肥大的复眼、三对猛禽附肢、由8至22个附肢组成的后躯干和八对鳃。尽管了解了它们的解剖结构，但许多问题仍然存在，特别是围绕古生代代表的解剖结构。美国俄克拉荷马州上泥盆统伍德福德页岩(上法门纪)出土了几种真节肢动物化石，其中包括两种袋头类:鞘翅类和伍德福德类。在这里，我们使用微型计算机x射线断层扫描重新探索C. woodfordi的全型解剖结构，说明了盾牌结构的精细细节，循环系统，消化系统和生殖系统，以及附体。本文首次在甲壳类动物中描述了盾状体的边缘褶皱和内层。woodfordi Concavicaris与famenia的另一种物种Concavicaris submarinus有相似之处，包括盾的形态和内部解剖结构。它还显示出与中生代分类群类似的组织结构，如Dollocaris ingens。所有这些都提供了重要的信息，这些信息对于重建头囊类动物的进化和亲缘关系至关重要。托马斯Laville。国家自然历史组织，巴黎帕尔萨姆·弗朗什-康普斯大学(UMR7207)，法国巴黎索邦大学(mnn - sorbonne university)，法国巴黎和生物化学组织(UMR 6282CNRS)，法国第戎，勃艮第，弗朗什-康普斯大学(EPHE)相应的作者。thomas.laville@ecomail.fr Thomas A. Hegna。美国纽约州弗里多尼亚纽约州立大学地质与环境科学系thomas.hegna@fredonia.edu marie - bsamatrice Forel。国家自然历史组织，巴黎帕尔萨蒙大学(UMR7207)，巴黎索邦大学(MNHN-Sorbonne university)，法国巴黎。marie-beatrice.forel@mnhn.fr西蒙·达罗克。范德比尔特大学地球与环境科学系，纳什维尔，拉维尔等人:WOODFORDI 2田纳西州，美国。simon.a.darroch@vanderbilt.edu Sylvain Charbonnier。国家自然历史组织，巴黎帕尔萨蒙大学(UMR7207)，巴黎索邦大学(MNHN-Sorbonne university)，法国巴黎。sylvain.charbonnier@mnhn.fr

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来源期刊

Palaeontologia Electronica 地学-古生物学

CiteScore

3.60

自引率

0.00%

发文量

审稿时长

>12 weeks

期刊介绍： Founded in 1997, Palaeontologia Electronica (PE) is the longest running open-access, peer-reviewed electronic journal and covers all aspects of palaeontology. PE uses an external double-blind peer review system for all manuscripts. Copyright of scientific papers is held by one of the three sponsoring professional societies at the author''s choice. Reviews, commentaries, and other material is placed in the public domain. PE papers comply with regulations for taxonomic nomenclature established in the International Code of Zoological Nomenclature and the International Code of Nomenclature for Algae, Fungi, and Plants.