Research Article |
Corresponding author: Wenlong Chen ( 48708209@qq.com ) Corresponding author: Huiming Chen ( mei0601@126.com ) Academic editor: Luis Ernesto Bezerra
© 2023 Xuankong Jiang, Jiajun Zhou, Jianguo Wang, Wenlong Chen, Huiming Chen.
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:
Jiang X, Zhou J, Wang J, Chen W, Chen H (2023) Description of the first stygobiotic species of the atyid shrimp genus Sinodina (Decapoda, Caridea, Atyidae) from Yunnan Province, China. ZooKeys 1186: 123-137. https://doi.org/10.3897/zookeys.1186.112657
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Sinodina Liang & Cai, 1999, a genus of atyid shrimp, is endemic to China and distributed only in the Yunnan-Guizhou Plateau. We describe here the thirteen species of Sinodina, and the first cave-dweller of the genus, Sinodina ashima sp. nov., collected from a limestone cave in Shilin County, Yunnan Province. This species can be distinguished from its congeners by the completely degraded pigment and eyes, the extremely long rostrum, the rostral formula and the absence of sexual dimorphism of the third and fourth pereiopods. A phylogenetic analysis based on four genes (COI, 16S, 18S, H3) shows that the new species strongly clustered with the type species of this genus, Sinodina gregoriana (Kemp, 1923), supporting the generic status of this new species.
Diversity, morphology, new species, phylogeny, stygobiont, taxonomy
The genus Sinodina Liang & Cai, 1999 belongs to the order Decapoda and the family Atyidae. It was established by
The morphology of Sinodina is similar to that of the genera Caridina and Neocaridina, and they share the same branchial formula. Sinodina can be identified by the simple and lamellar podobranch of the second maxilliped and the obvious sexual dimorphism, that is, the male possesses more spines and distinctive dilation on the propodus of the third and fourth pereiopod (
There are numerous caves in the karst areas of south China, which provided refuge for organisms in this area during the Neogene when the climate and habitat had been changing, especially after the Oligocene-Miocene boundary (
We surveyed Xiangshuiqing Cave in Shilin County, Yunnan Province twice in April and June 2023 and collected a total of 14 atyid shrimp specimens with strong cave morphological features. They were identified as a new species of Sinodina through morphological observations and molecular analysis. This species is the first stygobiont in the genus and the fourth cave atyid species in Yunnan Province, after three Caridina species, Caridina feixiana Cai & Liang, 1999, Caridina alu Cai & Ng, 2018 and Caridina aff. heterodactyla Liang & Yan, 1985 (
Specimens were collected by cage nets from a limestone cave in Shilin, Yunnan, southern China. Live animals were observed and photographed with a Sony A7R4A camera with a Sony FE 90 mm macro lens. Most of the specimens were preserved in 75% ethanol for morphological studies, and the remainder were preserved in absolute ethanol and stored at –40 °C for molecular research. All specimens are deposited at the Institute of Biology, Guizhou Academy of Sciences, Guiyang, China (IBGAS).
Specimens were examined, photographed and measured using a Leica M205A stereomicroscope equipped with a Leica DFC450 camera and LAS X software (v. 5.1, Leica, Germany). All images were edited with PHOTOSHOP CC 2019 software (v. 20.0.0, Adobe, USA).
The following abbreviations are used in the text: alt (altitude), cl (carapace length, measured from the postorbital margin to the posterior margin of the carapace), rl (rostral length, measured from the rostral tip to the postorbital margin) and tl (total length, measured from the rostral tip to the posterior margin of the telson). All measurements are in millimeters.
To verify the classification of the new species, a multi-genes phylogenetic analysis was conducted. Four specimens of Sinodina ashima sp. nov. were sampled. The ingroup of the matrix was composed of Sinodina gregoriana (Kemp, 1923), two cave-dweller species of Caridina, Caridina cavernicola Liang & Zhou, 1993 and Caridina sinanensis
Taxon | Voucher number | Collection data | GenBank number | Reference | |||
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COI | 16S | 18S | H3 | ||||
Sinodina ashima sp. nov. | GBZD-676 | Xiaoliao Cave, Shilin, Yunnan, China, 4. VI. 2023, X.K. Jiang leg. | – | OR537884 | OR539523 | – | This study |
GBZD-677 | OR536642 | OR537885 | OR539524 | – | This study | ||
GBZD-678 | OR536643 | OR537886 | OR539525 | – | This study | ||
GBZD-679 | OR536644 | OR537887 | OR539526 | – | This study | ||
Sinodina gregoriana | GBZD-238 | Yangwanqiao Reservoir, Weining, Guizhou, China, 17. X. 2020, X.K. Jiang & H.M. Chen leg. | – | OR537881 | OR539518 | OR540202 | This study |
GBZD-239 | – | – | OR539519 | OR540203 | This study | ||
GBZD-240 | – | – | OR539520 | OR540204 | This study | ||
GBZD-241 | – | OR537882 | OR539521 | OR540205 | This study | ||
Sinodina sp. | ZMB DNA-651 | Yunnan, China | – | FN995388 | – | – |
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Caridina cavernicola | – | Hechi, Guangxi. | MZ753498 | MZ753801 | – | – |
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Caridina sinanensis | – | Sinan, Guizhou, 25. I. 2019 | MT433963 | MT434874 | – | – |
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Neocaridina palmata | GBZD-098 | Lisong, Hezhou, Guangxi, China, 25. IV. 2021, X.K. Jiang leg. | OR536639 | – | OR539516 | OR540200 | This study |
Neocaridina hofendopoda | GBZD-141 | Sijia River, Yacai, Sanjiang, Guangxi, China, 15. III. 2021, X.K. Jiang, H.M. Chen & J.C. Lv leg. | OR536640 | – | OR539517 | OR540201 | This study |
Paracaridina guizhouensis | GBZD-562 | Longquan, Maopo, Yuping, Guizhou, China, 29. IV. 2022, X.K. Jiang, H.M. Chen & L.P. Ye leg. | OR536641 | OR537883 | OR539522 | OR540206 | This study |
Macrobrachium nipponense | GBZD-001 | Guangzhao Reservoir, Qinglong, Guizhou, China, 14. I. 2021, H.M. Chen leg. | OR536638 | OR537880 | OR539515 | OR540199 | This study |
Four loci, including two mitochondrial genes (cytochrome c oxidase subunit I and 16S rDNA) and two nuclear genes (18S rDNA and histone H3 gene) were used to conduct the analysis. Primer sequences are in Table
Genes | Primer | Sequence (from 5’ to 3’) | Reference |
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COI | LCO1490 | GGTCAACAAATCATAAAGATATTGG |
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HCO2198 | TAAACTTCAGGGTGACCAAAAAATCA | ||
16S | 16sA | ACTTGATATATAATTAAAGGGCCG |
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16sB | CTGGCGCCGGTCTGAACTCAAATC | ||
18S | 18s ai | CCTGAGAAACGGCTACCACATC |
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18s bi | GAGTCTCGTTCGTTATCGGA | ||
H3 | H3 AF | ATGGCTCGTACCAAGCAGAC(AGC)GC |
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H3 AR | ATATCCTTRGGCATRARTGTGAC |
Raw sequences were edited and assembled using SEQMAN PRO software (Lasergene v. 7.1; DNA Star, Inc., Madison, Wis., USA). Protein-coding gene sequences (COI and H3) were aligned based on amino acid translation using CLUSTALW in MEGA 7.0 (
PARTITIONFINDER 2 (
Maximum likelihood (ML) and Bayesian inference (BI) analyses were conducted to infer the phylogeny. ML was performed in RAXML v. 8.2.0 (
In addition, the pairwise p-distances between COI and 16S genes of all specimens of Sinodina ashima sp. nov. and Sinodina gregoriana were calculated with MEGA 7.0. One 16S sequence of Sinodina sp. derived from Genbank (Table
Holotype : male (rl 5.1 mm, cl 5.8 mm, tl 26.7 mm), China, Yunnan Province, Kunming City, Shilin County, Xiangshuiqing Cave, 24°45′27.53″N, 103°19′54.88″E, alt. 1790 m, 4. VI. 2023, Jiang X.K. leg. Paratypes. 2 males (rl 5.0–5.9 mm, cl 6.0–6.6 mm, tl 27.5–29.5 mm) and 8 females (rl 4.6–6.5 mm, cl 5.4–6.6 mm, tl 23.5–28.7 mm), collected with holotype; 3 females (rl 5.7–9.0 mm, cl 6.7–8.2 mm, tl 28.9–40.0 mm), same locality, III. 2023, Zhou J.J. leg.
Body color and eyes strongly degenerated. Rostrum extremely elongated and upturned, obviously beyond end of scaphocerite, rostral formula: 7–11 + 14–15/8–14. Male propodus of third and fourth pereiopod normal without dilation. Dactylus of third pereiopod with 4–6 spinules. Telson with 6–7 pairs of dorsal spines.
Body slender
(Fig.
Eyes
small, highly reduced, without ocular peduncle, only centre of cornea slightly pigmented (Figs
Carapace
smooth, glabrous, antennal spine acute, pterygostomian margin subrectangular, pterygostomian spine absent (Figs
Antennule
(Fig.
Antennal
(Fig.
Mandible
incisor process with six irregular and blunt teeth. Molar process truncated (Fig.
Maxillula
(Fig.
Maxilla
(Fig.
First maxilliped
(Fig.
Second maxilliped
(Fig.
Third maxilliped
(Fig.
First pereiopod
(Fig.
Second pereiopod
(Fig.
Third pereiopod
(Fig.
Fifth pereiopod
(Fig.
First pleopod
(Fig.
Second pleopod
endopod slender. Appendix masculina (Fig.
Telson
(Fig.
Eggs 0.85–0.91 × 1.20–1.27 in diameter.
Color
strongly degenerated, translucent to flavescent (Fig.
The specific name is in honor of Ashima, who is a famous female character of the local legend spreading among the Yi nationality and is a symbol of love and bravery.
Yunnan Province (Xiangshuiqing Cave), China.
Subterranean river in a karst cave.
The phylogenetic matrix included 14 terminals with 2262 nucleotides (COI: 647 bp; 16S: 453 bp; 18S: 867 bp; H3: 295 bp). The best-fitting evolutionary model for the first codon of COI, 18S and the first and second codons of H3 was TRNEF+I+G. The best model for the second codon of COI was HKY+G. TRNEF+I was the optimal model for the third codon of COI. HKY+I+G and TVM+G suited the 16S and the third codon of H3 respectively.
The only difference between the topologies derived from the ML and BI analyses was the position of Paracaridina guizhouensis. It was either sister to Sinodina spp. (ML) (Fig.
The COI sequences were successfully obtained from three specimens of Sinodina ashima sp. nov., but failed in all specimens of Sinodina gregoriana. The intraspecific p-distances of COI of the new species were 0% and 1.85%. Nevertheless, the 16S sequences of all specimens of Sinodina spp., but two ones of Sinodina gregoriana, have been obtained. No intraspecific variation in 16S of Sinodina ashima sp. nov. was detected, and the intraspecific p-distance of Sinodina gregoriana was 0.45%. The interspecific p-distances between Sinodina ashima sp. nov. and Sinodina gregoriana were 4.55% and 4.32%, between Sinodina ashima sp. nov. and Sinodina sp. were 2.05% and 2.27%, and between Sinodina gregoriana and Sinodina sp. was 4.09%.
Some morphological characteristics of Sinodina seem to be plesiomorphic. Its simple lamellar podobranch is the same as that of Caridina during the metamorphosis from the zoea to the first post-larval stage, without further development (
The new species with the simple and lamellar podobranch and its distribution is certainly a member of the genus Sinodina. This result is also supported by the phylogenetic analysis, in which Sinodina ashima sp. nov. is firmly clustered with the type species Sinodina gregoriana. As the first cave-dweller described in the genus, it can be easily distinguished from other species by its degraded body color and eyes. Besides, Sinodina ashima sp. nov. is similar to S. heterodactyla (Liang & Yan, 1985) and S. banna (Cai & Dai, 1999). They all show nearly no sexual dimorphism on the third and fourth pereiopod. The new species differs from the two species not only in the stygomorphic traits, but also in the extremely elongated and upturned rostrum, obviously beyond the end of scaphocerite (vs. S. heterodactyla reaching the end of scaphocerite and S. banna only reaching the end of the first segment of the antennular peduncle); the rostrum with 8–14 teeth ventrally (vs. 5–9 in S. heterodactyla and no ventral tooth in S. banna); the dactylus of male third pereiopod with 4–6 spines (vs. 7 in S. heterodactyla and 8–10 in S. banna); the body length 23–40 mm (vs. 23–32 mm in S. heterodactyla and 14–17 mm in S. banna).
Cave organisms in the karst region of south China have a long evolutionary history and high diversity (
We thank Mr Lei Chunyun (Yunnan Academy of Fishery Science, China) and Dr Liu Yewei (Guangxi University, China) for assistance during fieldwork. The comments by Dr Valentin de Mazancourt and Dr Luis Ernesto Bezerra helped to improve this paper.
The authors have declared that no competing interests exist.
No ethical statement was reported.
This research is supported by grants from the National Science and Technology Basic Research Program of China (2019FY101900), the National Natural Science Foundation of China (32100365), the Talents Platform Construction Program of Guizhou Province (2017571903), the Doctoral Foundation of Guizhou Academy of Sciences (R[2021]1) and the Forestry Reform and Development Fund of Guizhou Province (2021-01).
Formal analysis: XJ. Investigation: JZ, XJ. Methodology: HC. Resources: WC. Writing - original draft: XJ. Writing - review and editing: JW, JZ, WC, HC.
Xuankong Jiang https://orcid.org/0000-0003-3506-5894
Jiajun Zhou https://orcid.org/0000-0003-1038-1540
Jianguo Wang https://orcid.org/0009-0000-4675-4615
Wenlong Chen https://orcid.org/0009-0002-1170-3847
Huiming Chen https://orcid.org/0000-0002-2449-3036
All of the data that support the findings of this study are available in the main text.