Research Article |
Corresponding author: Manuel Lopes-Lima ( lopeslima.ciimar@gmail.com ) Academic editor: Richard Willan
© 2016 Olga K. Klishko, Manuel Lopes-Lima, Elsa Froufe, Arthur Bogan, Vera Y. Abakumova.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Klishko OK, Lopes-Lima M, Froufe E, Bogan AE, Abakumova VY (2016) Systematics and distribution of Cristaria plicata (Bivalvia, Unionidae) from the Russian Far East. ZooKeys 580: 13-27. https://doi.org/10.3897/zookeys.580.7588
|
The number of anodontine bivalve species placed in the genus Cristaria (Bivalvia, Unionidae) from the Russian Far East is still not stable among authors. Some recognize only one valid species C. plicata (Leach, 1815) while others accept two additional species, C. tuberculata Schumacher, 1817 and C. herculea (Middendorff, 1847). In the present study, these taxonomic doubts are addressed using analyses of mitochondrial DNA sequences and shell morphometry. No significant differences have been revealed by the COI DNA sequences or the main statistical morphometric indices from the three Cristaria forms. In the specimens analysed, changes in shell morphometry with age suggest that original descriptions of the different forms may be attributed solely to differences in age and sex. We consider that C. plicata, C. tuberculata and C. herculea from the Russian Far East should be considered as a single species, namely Cristaria plicata (Leach, 1815), with C. tuberculata and C. herculea as junior synonyms. The geographic range of Cristaria plicata and its conservation status are also presented here.
Bivalvia , Unionidae , Anodontini , COI, morphometry, Russia
It is well known that freshwater bivalves of the Unionidae provide important ecosystem functions (
The different classification systems used in Russia considerably hamper identification of species and inventories of the molluscan fauna. This is the situation for the taxonomy of freshwater bivalve species of the genus Cristaria from the Russian Far East, which has been contentious among taxonomists. According to the classification system of
Using a conchological classification system, some Far East Russian specimens from the collection of the Zoological Institute Museum, St. Petersburg (ZIM-SP) have been attributed only to C. tuberculata Schumacher, 1817 and indicated as the type species of the genus (
Only one conchological character, shell convexity, was used to separate both species. Cristaria herculea, with laterally compressed shells, is widespread in the Amur River basin and Khanka Lake in Russia, as well as the Buyr-Nor Lake in Mongolia. Cristaria tuberculata, with inflated shells, is rare and limited to the Russian Far East, in Khanka Lake and the Ussury River basin (
Based on conchological observations,
Despite all this evidence, these two species continue to be recognized as independent species by the Russian system of taxonomy (
The main goals of the present work are to establish the taxonomic status and phylogenetic relationships of C. tuberculata and C. herculea from the Russian Far East, and C. plicata from the adjacent territories of Transbaikalia and China. This will be achieved by using molecular analysis of the Cytochrome c Oxidase I gene fragment and morphometric statistical analysis of the shells. Finally, the distributional range of these taxa in Russia and Eastern Asia will also be evaluated.
For molecular analyses, C. tuberculata specimens were collected in 2014 from the Luchegorsky Reservoir, of Ussury River Basin, in Russian Far East. Cristaria herculea specimens from Khanka Lake, Primorye, were retrieved from the collection of the Institute of Biology and Soil Science, Far East Branch, Russian Academy of Sciences (Vladivostok). Whole genomic DNA was extracted from small tissue pieces of 2 C. tuberculata and 2 C. herculea individuals (Table
List of specimen samples sequenced (CO1) and GenBank accession numbers. *Unpublished
Species | Locality | Country | Code/GenBank | Study |
---|---|---|---|---|
Cristaria tuberculata | Luchegorsky reservoir | Russia | Biv1530/KT348507 | This study |
Cristaria tuberculata | Luchegorsky reservoir | Russia | Biv1531/KT348508 | This study |
Cristaria herculea | Onon River | Russia | Biv246/KT362704 |
|
Cristaria herculea | Charanorsky Reservoir | Russia | Biv247/KT362705 |
|
Cristaria herculea | Khanka Lake | Russia | Biv1537a/KU297678 | This study |
Cristaria herculea | Khanka Lake | Russia | Biv1537b/KU297678 | This study |
Cristaria plicata | Lower Yangtze | China | EU698893; EU698897; EU698913; EU698948 | Jia and Li* |
Cristaria plicata | Unknown | China | JF700152; JF700153 | Zhang et al.* |
Cristaria plicata | Zhejiang | China | FJ986302 |
|
Cristaria plicata | Unknown | South Korea | GQ451860 | Park et al.* |
Cristaria plicata | Unknown | South Korea | GU944476 |
|
Cristaria sp. | Lower Yangtze | China | EU698909; EU698910; EU698940; EU698942 | Jia and Li* |
Anodonta beringiana | Jo-Jo Lake | Canada | DQ272370 |
|
Sinanodonta woodiana | Unknown | Poland | HQ283347 | Soroka and Burzynski* |
For the C. herculea and C. tuberculata morphometric analyses, specimens of Cristaria from the collections of the Institute of Natural Resources, Ecology and Cryology, of the Russian Academy of Sciences Siberian Branch (INREC-RAS-SB) and from the Zoological Institute Museum, St. Petersburg (ZIM-SP), including the specimens used for the original species descriptions (
The distribution of Cristaria taxa in Far Eastern Russia and adjacent territories was compiled using data from the INREC-RAS-SB and ZIM-SP collections, and from an extensive bibliographic search (Suppl. material
Three haplotypes were retrieved from the four newly sequenced individuals: two in C. tuberculata specimens (i.e., Biv1530 and Biv1531; Fig.
Phylogenetic tree obtained by Bayesian Inference analysis, using mtDNA fragments (CO1). Support values are given as Bayesian posterior probability above nodes, except for those within major clades, which have been omitted for clarity. Available sequences downloaded from GenBank and new sequences codes refer to Table
The genus Cristaria exhibits high shell plasticity, common to most unionoid species. However, the basic shell morphology of Cristaria taxa from Russia identified by different authors as C. plicata, C. tuberculata and C. herculea is very similar (Fig.
Shell morphology of Cristaria plicata from Eastern Russia: A–C C. plicata from Khanka Lake identified by Zhadin in 1927 D–E C. plicata from Khanka Lake identified by Starobogatov in 1967 F–G C. tuberculata and H C. herculea from Khanka Lake identified by Moskvicheva in 1971 I limnetic, and J riverine forms of C. (herculea) plicata from Transbaikalia (
Not only do the morphometric characteristics change with the increase of shell length, but these may also vary considerably in shells from the same size. In fact, all morphometric indexes calculated in this study for Cristaria taxa showed wide variation (Figs
It should be noted that the R-index for the museum’s specimens of C. tuberculata identified by Moskvicheva in 1971 varied between 0.801–0.813 (shell lengths: 146–175 mm), identifying these specimens as C. herculea and not as C. tuberculata, according to the Key of
The values of the shell morphometric indexes (B/H, H/L and B/L) varied widely without separating any of the putative species groups (Fig.
Discriminant analysis revealed no differentiation into discrete entities or species with the distribution of all points (Wilk’s l = 0.852); the discriminant plot shows a considerable overlap in all taxa of Cristaria (Fig.
No statistically significant morphological discreteness was found between C. plicata and forms C. herculea and C. tuberculata for any of the morphometric indexes used, individually or combined. The reliability of morphological discreteness assessed by Wilk’s λ values for complex indexes values, were near to 1 which indicates the absence of morphological discreteness. A discriminant analysis provided no evidence of differentiation into entities or species (Wilk’s λ = 0.852, F (6.70) = 0.974, n = 40, p < 0.449).
Cristaria herculea is listed as Vulnerable in the Red Book of the Khabarovsky Krai (
Until now, according to the Russian system of taxonomy, C. herculea and C. tuberculata were considered valid species, both being considered as threatened in regional and national Russian Red Books. Using a synthesis of morphological and genetic data, we present categorical evidence that all forms of the genus Cristaria inhabiting in Russia are one species, C. plicata. This fact should be considered for future conservation measures. At the moment C. herculea and C. tuberculata are considered to be threatened in Eastern Russia and their populations are in decline due to anthropogenic impacts. Integrating both forms into the single species, C. plicata, should maintain a threatened conservation status in this region. However, it is necessary to reassess the conservation status for C. plicata, both at the regional and National (Russia) levels, using the entire distributional range and demographic trends of both previously recognized forms. Nevertheless, further research is still required on the abundance, distribution, ecology and threats to this species for a more accurate Global Red List assessment, especially in its Southern edge of distribution in China and Indochina.
Cristaria plicata is found across the territory of Far East Russia including the Onon, Shilka, Argun, Zeya, Bureya, Ussury river basins, the lower Amur River, the Tym River (Sakhalin Island) and Khanka Lake. It is also present in Mongolia (Buyr-Nur Lake), China (Dong Ting Lake and Poyang Lake of the Yangtze River Basin (
In a previous revision of the Far Eastern Anodontinae, and although specimens identified as C. plicata were already present in the collection of the ZIM-SP, the genus Cristaria was separated into two species, C. tuberculata and C. herculea (
The authors want to thank the editor, Dr. Richard Willan, and the two reviewers for their excellent comments and suggestions that significantly improved the manuscript. Special thanks go also to Dr. A.V. Chernyshev (Institute of Sea Biology of Far East Branch of the Russian Academy of Sciences, Vladivostok) for tissue samples of C. tuberculata from Luchegorsky reservoir (Ussury River basin) and Dr. E.M. Sayenko (Institute of Biology and Soil, Far East Branch of the Russian Academy of Sciences, Vladivostok) for tissue samples of C. herculea from Khanka Lake. We also thank Dr. P.V. Kijashko (Zoological Institute of Russian Academy of Sciences, St. Petersburg) for the help with the work on the Cristaria from the museum collections. The financial support for the genetics work was provided by the European Regional Development Fund (ERDF) through the COMPETE - Operational Competitiveness Program, and national funds through FCT – Foundation for Science and Technology, under a Grant to EF (SFRH/BPD/108445/2015) and under the Strategic Funding UID/Multi/04423/2013)
References used to determine Cristaria taxa distribution
Data type: references list
Explanation note: References used to determine Cristaria taxa distribution.
* - Museum of Zoological Institute, Russian Academy of Sciences, St.-Petersburg;
** - unpublished.