Michel Schmidt1,2,3, Yu Liu4,5, Xianguang Hou6,7, Joachim T Haug8,9, Carolin Haug8,9, Huijan Mai6,7, Roland R Melzer8,6,10,9. 1. Faculty of Biology, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany. mi.schmidt@campus.lmu.de. 2. MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China. mi.schmidt@campus.lmu.de. 3. Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstr. 21, 81247, Munich, Germany. mi.schmidt@campus.lmu.de. 4. MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China. yu.liu@ynu.edu.cn. 5. Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China. yu.liu@ynu.edu.cn. 6. MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China. 7. Yunnan Key Laboratory for Palaeobiology, Yunnan University, 2 North Cuihu Road, Kunming, 650091, People's Republic of China. 8. Faculty of Biology, Ludwig-Maximilians-Universität München, 82152, Planegg-Martinsried, Germany. 9. GeoBio-Center, Ludwig-Maximilians-Universität München, Richard-Wagner-Str. 10, 80333, Munich, Germany. 10. Bavarian State Collection of Zoology, Bavarian Natural History Collections, Münchhausenstr. 21, 81247, Munich, Germany.
Abstract
BACKGROUND: The Chengjiang biota from southwest China (518-million-years old, early Cambrian) has yielded nearly 300 species, of which more than 80 species represent early chelicerates, crustaceans and relatives. The application of µCT-techniques combined with 3D software (e.g., Drishti), has been shown to be a powerful tool in revealing and analyzing 3D features of the Chengjiang euarthropods. In order to address several open questions that remained from previous studies on the morphology of the xandarellid euarthropod Sinoburius lunaris, we reinvestigated the µCT data with Amira to obtain a different approach of visualization and to generate new volume-rendered models. Furthermore, we used Blender to design 3D models showing aspects of intraspecific variation. RESULTS: New findings are: (1) antennulae consist of additional proximal articles that have not been detected before; (2) compared to other appendages, the second post-antennular appendage has a unique shape, and its endopod is comprised of only five articles (instead of seven); (3) the pygidium bears four pairs of appendages which are observed in all specimens. On the other hand, differences between specimens also have been detected. These include the presence/absence of diplotergites resulting in different numbers of post-antennular appendages and tergites and different distances between the tip of the hypostome and the anterior margin of the head shield. CONCLUSIONS: Those new observations reveal intraspecific variation among Chengjiang euarthropods not observed before and encourage considerations about possible sexual dimorphic pairs or ontogenetic stages. Sinoburius lunaris is a variable species with respect to its morphological characters, cautioning that taxon-specific variabilities need to be considered when exploring new species.
BACKGROUND: The Chengjiang biota from southwest China (518-million-years old, early Cambrian) has yielded nearly 300 species, of which more than 80 species represent early chelicerates, crustaceans and relatives. The application of µCT-techniques combined with 3D software (e.g., Drishti), has been shown to be a powerful tool in revealing and analyzing 3D features of the Chengjiang euarthropods. In order to address several open questions that remained from previous studies on the morphology of the xandarellid euarthropod Sinoburius lunaris, we reinvestigated the µCT data with Amira to obtain a different approach of visualization and to generate new volume-rendered models. Furthermore, we used Blender to design 3D models showing aspects of intraspecific variation. RESULTS: New findings are: (1) antennulae consist of additional proximal articles that have not been detected before; (2) compared to other appendages, the second post-antennular appendage has a unique shape, and its endopod is comprised of only five articles (instead of seven); (3) the pygidium bears four pairs of appendages which are observed in all specimens. On the other hand, differences between specimens also have been detected. These include the presence/absence of diplotergites resulting in different numbers of post-antennular appendages and tergites and different distances between the tip of the hypostome and the anterior margin of the head shield. CONCLUSIONS: Those new observations reveal intraspecific variation among Chengjiang euarthropods not observed before and encourage considerations about possible sexual dimorphic pairs or ontogenetic stages. Sinoburius lunaris is a variable species with respect to its morphological characters, cautioning that taxon-specific variabilities need to be considered when exploring new species.
Entities:
Keywords:
3D modelling; Amira; Blender models; Intraspecific variation; Volume rendering
Authors: Yu Liu; Roland R Melzer; Joachim T Haug; Carolin Haug; Derek E G Briggs; Marie K Hörnig; Yu-Yang He; Xian-Guang Hou Journal: Proc Natl Acad Sci U S A Date: 2016-05-02 Impact factor: 11.205
Authors: Dayou Zhai; Mark Williams; David J Siveter; Thomas H P Harvey; Robert S Sansom; Sarah E Gabbott; Derek J Siveter; Xiaoya Ma; Runqing Zhou; Yu Liu; Xianguang Hou Journal: Commun Biol Date: 2019-09-03