title: Three-dimensionally preserved minute larva of a great-appendage arthropod from the early Cambrian Chengjiang biota.
abstract: A three-dimensionally preserved 2-mm-long larva of the arthropod Leanchoilia illecebrosa from the 520-million-year-old early Cambrian Chengjiang biota of China represents the first evidence, to our knowledge, of such an early developmental stage in a short-great-appendage (SGA) arthropod. The larva possesses a pair of three-fingered great appendages, a hypostome, and four pairs of well-developed biramous appendages. More posteriorly, a series of rudimentary limb Anlagen revealed by X-ray microcomputed tomography shows a gradient of decreasing differentiation toward the rear. This, and postembryonic segment addition at the putative growth zone, are features of late-stage metanauplii of eucrustaceans. L. illecebrosa and other SGA arthropods, however, are considered representative of early chelicerates or part of the stem lineage of all euarthropods. The larva of an early Cambrian SGA arthropod with a small number of anterior segments and their respective appendages suggests that posthatching segment addition occurred in the ancestor of Euarthropoda.
authors.affiliation: Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, People's Republic of China; Department Biology II, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany; GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 Munich, Germany;
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department Biology II, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany; GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 Munich, Germany; Bavarian State Collection of Zoology, Bavarian Natural History Collections, 81247 Munich, Germany;
authors.forename: Roland R
authors.initials: RR
authors.lastname: Melzer
authors.affiliation: Department Biology II, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany; GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 Munich, Germany;
authors.forename: Joachim T
authors.initials: JT
authors.lastname: Haug
authors.affiliation: Department Biology II, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany; GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 Munich, Germany;
authors.forename: Carolin
authors.initials: C
authors.lastname: Haug
authors.affiliation: Department of Geology and Geophysics, Yale University, New Haven, CT 06520-8109; Peabody Museum of Natural History, Yale University, New Haven, CT 06520-8109;
authors.forename: Derek E G
authors.initials: DE
authors.lastname: Briggs
authors.affiliation: Cytology and Evolutionary Biology, Zoological Institute and Museum, Ernst-Moritz-Arndt-University of Greifswald, 17487 Greifswald, Germany.
authors.forename: Marie K
authors.initials: MK
authors.lastname: Hörnig
authors.affiliation: Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, People's Republic of China;
authors.forename: Yu-Yang
authors.initials: YY
authors.lastname: He
authors.affiliation: Yunnan Key Laboratory for Palaeobiology, Yunnan University, Kunming 650091, People's Republic of China; xghou@ynu.edu.cn.
authors.forename: Xian-Guang
authors.initials: XG
authors.lastname: Hou
mesh_terms: D000818:Animals; D001181:Arthropods / Q000033:anatomy & histology* / Q000648:ultrastructure; D058448:Biota; D002681:China; D007814:Larva / Q000033:anatomy & histology* / Q000648:ultrastructure; D014057:Tomography, X-Ray Computed
keywords: 3D preservation; Cambrian radiation; Chengjiang biota; arthropod larva; micro-CT