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Wiese R, Harrington K, Hartmann K, Hethke M, von Rintelen T, Zhang H, Zhang L, Riedel F. Can fractal dimensions objectivize gastropod shell morphometrics? A case study from Lake Lugu (SW China). Ecol Evol 2022; 12:e8622. [PMID: 35261738 PMCID: PMC8888252 DOI: 10.1002/ece3.8622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 11/13/2022] Open
Abstract
Morphometrics are fundamental for the analysis of size and shape in fossils, particularly because soft parts or DNA are rarely preserved and hard parts such as shells are commonly the only source of information. Geometric morphometrics, that is, landmark analysis, is well established for the description of shape but it exhibits a couple of shortcomings resulting from subjective choices during landmarking (number and position of landmarks) and from difficulties in resolving shape at the level of micro-sculpture.With the aid of high-resolution 3D scanning technology and analyses of fractal dimensions, we test whether such shortcomings of linear and landmark morphometrics can be overcome. As a model group, we selected a clade of modern viviparid gastropods from Lake Lugu, with shells that show a high degree of sculptural variation. Linear and landmark analyses were applied to the same shells in order to establish the fractal dimensions. The genetic diversity of the gastropod clade was assessed.The genetic results suggest that the gastropod clade represents a single species. The results of all morphometric methods applied are in line with the genetic results, which is that no specific morphotype could be delimited. Apart from this overall agreement, landmark and fractal dimension analyses do not correspond to each other but represent data sets with different information. Generally, the fractal dimension values quantify the roughness of the shell surface, the resolution of the 3D scans determining the level. In our approach, we captured the micro-sculpture but not the first-order sculptural elements, which explains that fractal dimension and landmark data are not in phase.We can show that analyzing fractal dimensions of gastropod shells opens a window to more detailed information that can be considered in evolutionary and ecological contexts. We propose that using low-resolution 3D scans may successfully substitute landmark analyses because it overcomes the subjective landmarking. Analyses of 3D scans with higher resolution than used in this study will provide surface roughness information at the mineralogical level. We suggest that fractal dimension analyses of a combination of differently resolved 3D models will significantly improve the quality of shell morphometrics.
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Affiliation(s)
- Robert Wiese
- Institute of Geological SciencesFreie Universität BerlinBerlinGermany
| | - Kyle Harrington
- Virtual Technology & DesignUniversity of IdahoMoscowIdahoUSA
- Image Data AnalysisMax Delbrück Center for Molecular MedicineBerlinGermany
- Computational Sciences and EngineeringOak Ridge National LaboratoryOak RidgeTennesseeUSA
| | - Kai Hartmann
- Institute of Geological SciencesFreie Universität BerlinBerlinGermany
- Institute of Geographical SciencesFreie Universität BerlinBerlinGermany
| | - Manja Hethke
- Institute of Geological SciencesFreie Universität BerlinBerlinGermany
| | - Thomas von Rintelen
- Museum für NaturkundeLeibniz‐Institut für Evolutions‐ und BiodiversitätsforschungBerlinGermany
| | - Hucai Zhang
- Institute for Ecological Research and Pollution Control of Plateau LakesSchool of Ecology and Environmental ScienceYunnan UniversityKunmingChina
| | - Le‐Jia Zhang
- Museum für NaturkundeLeibniz‐Institut für Evolutions‐ und BiodiversitätsforschungBerlinGermany
| | - Frank Riedel
- Institute of Geological SciencesFreie Universität BerlinBerlinGermany
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Carr AN, Nestler JH, Vliet KA, Brochu CA, Murray CM, Shirley MH. Use of continuous cranial shape variation in the identification of divergent crocodile species of the genus Mecistops. J Morphol 2021; 282:1219-1232. [PMID: 33945166 DOI: 10.1002/jmor.21365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 04/22/2021] [Accepted: 05/02/2021] [Indexed: 11/10/2022]
Abstract
The discovery of cryptic biodiversity has blossomed under the advancements of genetic techniques, but species identification via morphology remains crucial to effective conservation efforts. In this study, we tested the use of continuous cranial shape variation in distinguishing the two living species of Mecistops: the West African slender-snouted crocodile (M. cataphractus) and the Central African slender-snouted crocodile (M. leptorhynchus). Using a combination of geometric morphometric characters and ratios of linear measurements, we identified statistically significant variation in cranial bone and overall skull shape of mature individuals that corroborates existing molecular and discrete morphological evidence for two distinct, extant species within Mecistops. Specifically, variation in the shape of the nasal appears particularly diagnostic, while ratios involving metrics of snout length to snout width at the premaxillary notch offer distinguishing features easily measured in the field. Because of the complementary results and applications of the morphometric and cranial ratio analyses, we argue that both methodologies remain relevant to species identification. Moreover, we recommend continued cooperation between geneticists and morphologists in diagnosing species of conservation concern.
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Affiliation(s)
- Amanda N Carr
- Department of Wildlife Ecology & Conservation, University of Florida, Gainesville, Florida, USA
| | | | - Kent A Vliet
- Department of Biology, University of Florida, Gainesville, Florida, USA
| | - Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Christopher M Murray
- Department of Biological Sciences, Southeastern Louisiana University, Hammond, Louisiana, USA
| | - Matthew H Shirley
- Institute of Environment, Florida International University, North Miami, Florida, USA.,Project Mecistops, Sarasota, Florida, USA
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Hu Y, Gao MZ, Huang P, Zhou HL, Ma YB, Zhou MY, Cheng SY, Xie HG, Lv ZY. Taxonomic integrative and phylogenetic identification of the first recorded Triatoma rubrofasciata in Zhangzhou, Fujian Province and Maoming, Guangdong Province, China. Infect Dis Poverty 2019; 8:70. [PMID: 31409377 PMCID: PMC6693202 DOI: 10.1186/s40249-019-0579-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 07/19/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Most species of Triatominae live exclusively in Latin America. However, one species, Triatoma rubrofasciata, has been recorded in the Americas as well as in various port areas in Africa and Asia. An increasing number of T. rubrofasciata have been reported in southern China in recent years. However, the origin of this invasive insect vector in China remains unknown, therefore, accurate identification and phylogenetic analysis of the bugs are urgently needed. METHODS A total of seven triatomine insect specimens were found and collected from Maoming City, Guangdong Province, China (GDMM) and Zhangzhou City, Fujian Province, China (FJZZ), respectively. The obtained insect vector specimens were observed under a dissecting microscope for morphological classification and then the genomic DNA was extracted, and the 16S ribosomal RNA (rRNA), 28S rRNA as well as cytochrome oxidase subunit I (COI) genes of the species were amplified and sequenced. Subsequently, molecular phylogenetic analyses based on multiple alignments of the above genes were conducted in order to identify the species and determine the phylogenetic origin approximation accurately. RESULTS The triatomine insects collected from GDMM and FJZZ were identified as Triatoma rubrofasciata using morphological and genetic analyses. All of the Chinese T. rubrofasciata captured in FJZZ, GDMM and other localities in southern China, together with a Vietnamese and Brazilian strain, formed a new, cohesive clade. T. rubrofasciata in GDMM and FJZZ are likely derived from strains found in Vietnam or Brazil. CONCLUSIONS To the best of our knowledge, this is the first record of the invasive insect T. rubrofasciata, which is likely derived from strains native to Vietnam or Brazil, in both Maoming City, Guangdong Province and Zhangzhou City, Fujian Province of China. A comparison of the DNA sequences of the 16 s rRNA, 28 s rRNA and COI genes confirmed the specific identification of T. rubrofasciata, and its potential origin in China is based on the phylogenetic analyses undertaken in this study. More targeted interventions and improved entomological surveillance are urgently needed to control the spread of this haematophagous insect in China.
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Affiliation(s)
- Yue Hu
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Min-Zhao Gao
- Department of Gastroenterology of the Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, 519000, China
| | - Ping Huang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Hong-Li Zhou
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Yu-Bin Ma
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Min-Yu Zhou
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Shao-Yun Cheng
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.,Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, 510080, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China
| | - Han-Guo Xie
- Fujian Center for Disease Control and Prevention, Fuzhou, 350001, China.
| | - Zhi-Yue Lv
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China. .,Key Laboratory of Tropical Disease Control (Sun Yat-sen University), Ministry of Education, Guangzhou, 510080, China. .,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, 510080, China.
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