Research Article |
Corresponding author: Jie-Xin Zou ( jxzou@ncu.edu.cn ) Academic editor: Saskia Brix
© 2021 Qi-Hong Tan, Xiao-Juan Zhou, Jie-Xin Zou.
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:
Tan Q-H, Zhou X-J, Zou J-X (2021) Two new species of freshwater crab of the genus Aparapotamon Dai & Chen, 1985 (Crustacea, Brachyura, Potamidae) from Yunnan, China. ZooKeys 1056: 149-171. https://doi.org/10.3897/zookeys.1056.63755
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Two new species of freshwater crab of the genus Potamid Aparapotamon Dai & Chen, 1985 are described from Yunnan Province, southwest China. Morphological comparisons were made between the two new species and type materials of other 11 species of Aparapotamon. Aparapotamon binchuanense sp. nov. and A. huizeense sp. nov. can be separated from their congeners by the shape of the epibranchial tooth, the frontal view of the cephalothorax, the male first gonopod, and the female vulvae. The molecular analyses based on partial mitochondrial 16S rRNA gene are also included. This study brings the number of Aparapotamon species to 13.
Aparapotamon, freshwater crab, new species, taxonomy, 16S rRNA
Crabs of the family Potamidae Ortmann, 1896 (Crustacea, Decapod, Brachyura) spend their whole life history in freshwater or terrestrial environments (
Previous studies have shown that China has the world’s highest number of freshwater crab species (
Aparapotamon was established by
Specimens were collected by Han Dai from Biji Village (25°53'34"N, 100°55'30"E, alt. 1658 m), Lawu Town, Binchuan County, Dali Bai Autonomous Prefecture, Yunnan Province and Yue Huang from Zebu Village (26°30'41"N, 103°10'25"E, alt. 1954 m), Nagu Town, Huize County, Qujing City, Yunnan Province, respectively. All materials were preserved in 95% ethanol and deposited in the Department of Parasitology of the Medical College of Nanchang University, Jiangxi, China (
We compared two new species with type materials of other eleven species of Aparapotamon deposited in Chinese Academy of Sciences, Beijing, China (
Institutional abbreviations used in the paper are as follows:
NNU College of Life Sciences, Nanjing Normal University, Nanjing, China;
SYSBM Sun Yat-sen Museum of Biology, Sun Yat-Sen University, Guangzhou, China;
The pereiopod muscle tissue was extracted from specimens of the new species with a DP1902 Tissue Kit (BioTeKe Inc. Beijing). Partial mitochondrial 16S rRNA gene sequences were obtained by PCR amplification with the primers 1471 (5’-CCTGTTTANCAAAAACAT-3’) and 1472 (5’-AGATAGAAACCAACCTGG-3’) (
For molecular analysis, 30 partial sequences of 16S rRNA gene were used to construct BI and ML phylogenetic trees, including those of 27 species in 22 genera of potamids (Table
Species | Museum catalogue no. | Locality | GenBank no. | Reference |
---|---|---|---|---|
Aparapotamon grahami |
|
Yunnan, China | AB428489 |
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Cryptopotamon anacoluthon Kemp, 1918 |
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Hong Kong | AB428453 |
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Daipotamon minos Ng & Trontelj, 1996 |
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Guizhou, China | LC198524 |
|
Diyutamon cereum Huang, Shih & Ng, 2017 | SYSBM | Guizhou, China | LC198520 |
|
Mediapotamon leishanense Dai, 1995 | SYSBM001094 | Guizhou, China | LC155164 |
|
Minpotamon nasicum Dai & Chen, 1979 |
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Fujian, China | AB428450 |
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Nanhaipotamon hongkongense Shen, 1940 |
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Hong Kong, China | AB212869 |
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Parapotamon spinescens Calman, 1905 |
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Yunnan, China | AB428467 |
|
Pararanguna semilunatum Dai & Chen, 1985 |
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Yunnan, China | AB428490 |
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Potamiscus yongshengense Dai & Chen, 1985 | NNU150951 | Yunnan, China | KY963597 |
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Socotrapotamon nojidensis Apel & Brandis, 2000 |
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Socotra, Yemen | AB428493 |
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Tenuipotamon huaningense Dai & Bo, 1994 | CAS CB05175 | Yunnan, China | AB428491 |
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Trichopotamon daliense Dai & Chen, 1985 |
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Yunnan, China | AB428492 |
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Yarepotamon fossor Huang, 2018 | SYSBM 001417 | Guangxi, China | MG709238 |
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Artopotamon latopeos Chu, Wang & Sun, 2018 | NNU 170502 | Yunnan, China | MH045061 |
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Arquatopotamon jizushanense Chu, Zhou & Sun, 2017 | NNU 160506 (holotype) | Yunnan, China | KY963596 |
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Semicirculara lincangensis Chu, Wang & Sun, 2018 | NNU 1605 | Yunnan, China | MH045059 |
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Tenuilapotamon latilum Chen, 1980 |
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Hubei, China | AB428468 |
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Sinopotamon davidi Rathbun, 1904 |
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Shaanxi, China | LC155132 |
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Tiwaripotamon xiurenense Dai & Naiyanetr, 1994 |
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Guangxi, China | LC198522 |
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Cantopotamon zhuhaiense Huang, Ahyong & Shih, 2017 | SYSBM 001439 | Guangdong, China | LC342045 |
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Qianguimon splendidum Huang, 2018 | SYSBM 001598 | Guangxi, China | MG709241 |
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Artopotamon compressum |
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Yunnan, China | MN594116 | This study |
Aparapotamon huiliense |
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Yunnan, China | MN594113 | This study |
Aparapotamon huiliense |
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Yunnan, China | MN594118 | This study |
Aparapotamon similium |
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Yunnan, China | MN594114 | This study |
Aparapotamon binchuanense sp. nov. |
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Yunnan, China | MN943639 | This study |
Aparapotamon binchuanense sp. nov. |
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Yunnan, China | MN594120 | This study |
Aparapotamon huizeense sp. nov. |
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Yunnan, China | MN594121 | This study |
Aparapotamon huizeense sp. nov. |
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Yunnan, China | MN594122 | This study |
Aparapotamon grahami Dai & Chen, 1985
Holotype
:
Carapace trapezoidal, regions defined. External orbital angle triangular, postorbital cristae convex, postfrontal lobe prominent. Cervical groove indistinct, H-shaped groove conspicuous. Epibranchial tooth blunt, anterolateral margin lined with numerous granules. Third maxilliped exopod without flagellum. Adult male and female chelipeds slightly unequal. Ambulatory legs relatively slender. Male sterno-pleonal cavity deep, median longitudinal groove between sternites 7/8 long. Male pleon narrow triangular, telson triangular. Vulva small, ovate, located close to each other at anterior part of sternites 6, posterior margin not convex. G1 slender, distal end tapering, distinctly bent. G2 basal segment ovate, tip of terminal segment laterally flattened.
Carapace width 1.25 × length (n = 7), regions defined; dorsal surface slightly convex (Figs
Third maxilliped exopod without flagellum, claviform, reaching proximal 1/3 of merus lateral margin (Figs
Aparapotamon binchuanense sp. nov. Holotype male (17.1 × 13.6 mm) (
Chelipeds slightly unequal in both adult male and female, right cheliped larger (Fig.
Male thoracic sternum punctate, formed by tidy depression; sternites 1–4 broad, sternites 1/2 completely continuous; suture 2/3 complete, transverse; suture 3/4 visible, mesially reaching distolateral part of sterno-pleonal cavity (Fig.
G1 slender; terminal segment claviform, distal end tapering, distinctly bent, inner margin arc-shaped, outer margin straight, dorsal lobe barely visible in ventral view (Fig.
The species is named after the type locality, Binchuan County, Dali Bai Autonomous Prefecture, Yunnan Province.
The new species is presently known only from the type locality, Binchuan County, Dali Bai Autonomous Prefecture, Yunnan Province.
Aparapotamon binchuanense sp. nov. closely resembles congeners in general carapace morphology. However, A. binchuanense sp. nov. can be distinguished from other species by the terminal segment of G1, which is claviform, with distal end tapering and distinctly bent (Fig.
(Fig.
Holotype
:
Carapace trapezoidal, dorsal surface slightly convex, regions defined. External orbital angle round, separated from anterolateral margin, postorbital cristae convex, postfrontal lobe prominent. Cervical groove shallow, H-shaped groove distinct, especially in female specimen. Epibranchial tooth distinct, especially in female specimen. Third maxilliped exopod without flagellum. Ambulatory legs slender. Male pleon broad triangular, telson triangular, apex rounded. Vulva ovate, covering anterior half of sternite 6, with the posterior margin distinctly convex. G1 very slender, dorsal lobe well developed, exceeding suture 4/5 in situ, G2 basal segment ovate, tip of terminal segment round.
Carapace width 1.25 × length (n = 8), regions distinctly defined; dorsal surface slightly convex, anterolateral and frontal region covered with conspicuous round granules (Fig.
Third maxilliped exopod without flagellum, claviform, reaching proximal 1/3 of merus lateral margin (Figs
Aparapotamon huizeense sp. nov. Holotype male (25.9 × 21.2 mm) (
Male thoracic sternum punctate, formed by tidy depression; sternites 1–4 broad, sternites 1/2 completely continuous; suture 2/3 complete, transverse; suture 3/4 visible, mesially reaching distolateral part of sterno-pleonal cavity (Fig.
G1 very slender; terminal segment claviform, slightly bent distally, inner margin arc-shaped, outer margin straightly, dorsal lobe well developed and gonopod pore located in it (Fig.
The species is named after the type locality, Huize County, Qujing City, Yunnan Province.
The new species is presently known only from the type locality presently, Huize County, Qujing City, Yunnan Province.
Aparapotamon huizeense sp. nov. closely resembles A. grahami in the general carapace morphology and G1 structure. However, A. huizeense sp. nov. can be distinguished from A. grahami by the following characters: G1 exceeding suture 4/5 in situ (Fig.
Left G1s. A Aparapotamon binchuanense sp. nov.
Species/characters | Epibranchial tooth | Pterygostomial and sub-hepatic regions | Sub-orbital region | G1 in situ | Terminal segment of G1 | Vulva |
---|---|---|---|---|---|---|
A. binchuanense sp. nov. | Blunt (Fig. |
Densely covered with round granules (Fig. |
Sparely covered with round granules (Fig. |
Exceeding pleonal locking tubercle but not suture 4/5 (Fig. |
Slender, distal end tapering, distinctly bent (Fig. |
Ovate, posterior margin not convex (Fig. |
A. huizeense sp. nov. | Sharp (Fig. |
Sparely covered with round granules (Fig. |
Smooth (Fig. |
Exceeding suture 4/5 (Fig. |
Very slender, distal end slightly bent, dorsal lobe well developed inward (Fig. |
Ovate, posterior margin distinctly convex (Fig. |
A. inflomanum (cf. |
Blunt | Smooth | Smooth | Reaching suture 4/5 | Slender, distal end disc-shaped (Fig. |
Ovate, posterior margin not convex |
A. molarum (cf. |
Blunt | Smooth | Smooth | Exceeding suture 4/5 | Slender, distal end disc-shaped (Fig. |
Transversely ovate, posterior margin not convex |
A. emineoforaminum (cf. |
Blunt | Densely covered with round granules | Smooth | Exceeding suture 4/5 | Very slender, tapering distally (Fig. |
Ovate, posterior margin distinctly convex |
A. tholosum (cf. |
Sharp | Densely covered with round granules | Smooth | Exceeding pleonal locking tubercle but not suture 4/5 | Slender, dorsal lobe well developed upwards (Fig. |
Transversely ovate, posterior margin distinctly convex |
A. protinum (cf. |
Sharp | Densely covered with round granules | Smooth | Exceeding pleonal locking tubercle but not suture 4/5 | Slender, dorsal lobe slightly developed upwards (Fig. |
Transversely ovate, posterior margin arching to form semicircular structure |
A. arcuatum (cf. |
Blunt | Sparely covered with round granules | Smooth | Exceeding pleonal locking tubercle but not suture 4/5 | Slender, arc-shaped, dorsal lobe slightly developed upwards (Fig. |
Transversely ovate, posterior margin not convex |
A. muliense (cf. |
Blunt | Sparely covered with round granules | Smooth | Exceeding pleonal locking tubercle but not suture 4/5 | Slender, arc-shaped, dorsal lobe well developed upwards (Fig. |
Transversely ovate, posterior margin distinctly convex |
A. grahami (cf. |
Sharp | Sparely covered with round granules | Smooth | Reaching pleonal locking tubercle | Slender, dorsal lobe variably developed inwards (Fig. |
Ovate, posterior margin slightly convex |
A. huiliense (cf. |
Sharp | Sparely covered with round granules | Smooth | Exceeding pleonal locking tubercle but not suture 4/5 | Slender, dorsal lobe roundly developed (Fig. |
Transversely ovate, posterior margin slightly convex |
A. similium (cf. |
Blunt | Densely covered with round granules | Sparely covered with round granules | Exceeding pleonal locking tubercle but not suture 4/5 | Slender, dorsal lobe slightly developed inwards, tapering distally (Fig. |
Transversely ovate, posterior margin distinctly convex |
A. gracilipedum (cf. |
Sharp | Densely covered with round granules | Sparely covered with round granules | Exceeding pleonal locking tubercle but not suture 4/5 | Slender, dorsal lobe slightly developed inwards, distal end blunt (Fig. |
Ovate, posterior margin slightly convex |
Thirty 529 bp 16S rRNA gene sequences were used to construct BI and ML trees. The phylogenetic tree in this study included five species of Aparapotamon, and the results showed that they were clustered into one clade (Fig.
species | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
A. grahami AB428489 | ||||||||
A. similium MN594114 | 0.0095 | |||||||
A. huiliense MN594113 | 0.0038 | 0.0095 | ||||||
A. huiliense MN594118 | 0.0038 | 0.0095 | 0.0000 | |||||
A. binchuanense sp. nov. MN943639 | 0.0019 | 0.0076 | 0.0019 | 0.0019 | ||||
A. binchuanense sp. nov. MN594120 | 0.0019 | 0.0076 | 0.0019 | 0.0019 | 0.0000 | |||
A. huizeense sp. nov. MN594121 | 0.0057 | 0.0038 | 0.0057 | 0.0057 | 0.0038 | 0.0038 | ||
A. huizeense sp. nov. MN594122 | 0.0057 | 0.0038 | 0.0057 | 0.0057 | 0.0038 | 0.0038 | 0.0000 |
There are currently 13 species in this genus including those described in this study. The original eleven species of Aparapotamon are morphologically diverse, with the distal end of G1s of A. inflomanum and A. molarum being disc-shaped but that of A. emineoforaminum tapering distally, and the three G1s extend to suture 4/5, while the other eight species have G1s that are claviform in terminal segment and distal ends do not extend to suture 4/5 (
In this study, 30 sequences of 16S rRNA gene from 27 species of 22 genera were used to performed phylogenetic analyses. Since the two new species cluster with other Aparapotamon species form a separate branch in clade (Fig.
The present molecular results show five species of Aparapotamon were clustered into one clade. And Aparapotamon cluster with other genera from Yunnan form ‘Yunnan’ clade. The genera in the branch of ‘Yunnan’ have many similarities in terms of morphological structure, such as the G1 slender, the terminal segment is longer than the half of subterminal segment, third maxilliped exopod without flagellum, and the ability to live at an altitude of 1500–2900 meters (
We thank Song-Bo Wang very sincerely for his guidance in writing and data analysis. We also thank Chao Huang and Yi-Yang Xu for providing specimens for morphological study and appraising the two new species when we identified them. Finally, we give a special thanks to the Subject editor and Tohru Naruse, Jin-Ho Park, William Santana, and Peter K. L. Ng for greatly improving our manuscript.
This work was supported by the National Natural Science Foundation of China (Nos. 32060306 and 21866020), the National Parasitic Resources Center (NPRC-2019-194-30), the Nanchang University College Students’ Innovation and Entrepreneurship Training Program (No. 2020CX298), Nanchang University’s Scientific Research Training Program (No. 15334).
BI tree
Data type: Tre. file
Explanation note: Phylogenetic.
ML tree
Data type: MTSX file
Explanation note: Phylogenetic.
Sequences
Data type: FASTA. file
Explanation note: Genomic.