Research Article |
Corresponding author: Shuqiang Li ( lisq@ioz.ac.cn ) Academic editor: Charles Oliver Coleman
© 2018 Zhonge Hou, Shuqiang Li.
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:
Hou Z, Li S (2018) Four new Gammarus species from Tibetan Plateau with a key to Tibetan freshwater gammarids (Crustacea, Amphipoda, Gammaridae). ZooKeys 747: 1-40. https://doi.org/10.3897/zookeys.747.21999
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Four new species of the genus Gammarus are described and illustrated from Tibetan Plateau. Gammarus altus sp. n. and G. limosus sp. n. are characterized by pereopods III–IV with a few short setae and uropod III with marginal spines accompanied by short setae. Gammarus kangdingensis sp. n. and G. gonggaensis sp. n. are characterized by pereopods III–IV with long straight setae on posterior margins and inner ramus of uropod III 0.4 times as long as outer ramus. Detailed morphological comparisons with related species are discussed. A key to 15 Gammarus species from the Tibetan Plateau and a map of their distributions are provided.
Amphipoda , diversification, freshwater, taxonomy
The Tibetan Plateau is the highest and largest plateau in the world, and arguably the most prominent topological feature on Earth (
The Holarctic amphipod genus Gammarus contains more than 200 described species (
Distribution map of Gammarus species from Tibetan Plateau. Type localites are shown for species 1–14. 1 Gammarus altus sp. n. 2 G. kangdingensis sp. n. 3 G. gonggaensis sp. n. 4 G. limosus sp. n. 5 G. sinuolatus Hou & Li, 2004 6 G. frigidus Hou & Li, 2004 7 G. lasaensis Barnard & Dai, 1988 8 G. jaspidus Hou & Li, 2004 9 G. abstrusus Hou, Platvoet & Li, 2006 10 G. emeiensis Hou, Li & Koenemann, 2002 11 G. hongyuanensis Barnard & Dai, 1988 12 G. sichuanensis Hou, Li & Zheng, 2002 13 G. praecipuus Li, Hou & An, 2013 14 G. glaber Hou, 2017 15 Gammarus lacustris Sars, 1863 based on material used in
The specimens were collected along the bank of streams flowing from high mountains with a fine-meshed hand net. Samples were preserved in 95% ethanol in the field and deposited in a -20°C refrigerator for long-term preservation. The body length of each amphipod was recorded by holding the specimen straight and measuring the distance along the dorsal side of the body from the base of the first antenna to the base of the telson. All dissected appendages were mounted in glycerol on slides. Appendages were drawn using a Leica DM2500 compound microscope equipped with a drawing tube. The specimens are lodged in the Institute of Zoology, Chinese Academy of Sciences (
Gammarus pulex (Linnaeus, 1758).
Holotype: male (
The specific name alludes to its typical biotope, living in high altitude; adjective.
Pereopods III and IV with a few setae on posterior margins; pereopods V–VII slender, bases elongated, carpus and propodus with spines on anterior margins but few setae; epimeral plates with blunt posterodistal corners; uropod III inner ramus length approx. one-third of outer ramus length, both rami with marginal spines but with few marginal setae.
(
Head. (Fig.
Antenna I (Fig.
Antenna II (Fig.
Upper lip (Fig.
Mandible (Fig.
Lower lip (Fig.
Maxilla I (Fig.
Maxilla II (Fig.
Maxilliped (Fig.
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Pereopod III (Fig.
Pereopod IV (Fig.
Pereopod V (Fig.
Pereopod VI (Fig.
Pereopod VII (Fig.
Coxal gills (Figs
Pleon. Epimeral plates (Fig.
Pleopods (Fig.
Urosome. Urosomites (Fig.
Uropod I (Fig.
Uropod II (Fig.
Uropod III (Fig.
Telson (Fig.
(
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Oostegite: present on gnathopod II and pereopods III–V.
Urosome. Uropod III (Fig.
This species was collected from a stream with altitude 4000 m, water clear and cold. There are a few water plants in the locality.
Gammarus altus sp. n. is most similar to G. glaber Hou, 2017 in having some setae on posterior margins of pereopods III and IV , and uropod III inner ramus length around one-third of outer ramus length, both rami with spines but few setae. The new species can be distinguished from G. glaber by the following characters (G. glaber in parentheses): second article of palp with two groups of B-setae (a group of B-setae); bases of pereopods V–VII elongated (broad), narrowing distally (posterior margin of pereopods V and VI nearly straight); uropod III with spines accompanied by simple setae on inner margin (uropod III with spines accompanied by plumose setae); and telson with no medial spines on surface (with one or two spines on medial surface).
This species is similar to G. sichuanensis Hou, Li & Zheng, 2002 in peduncle of antenna I and II with two or three groups of setae along anterior and posterior margins, and pereopod IV with a few setae on posterior margin. It differs from G. sichuanensis (G. sichuanensis in parentheses) by pereopod III with short setae on posterior margins of merus and carpus (with long setae on posterior margins of merus and carpus); bases of pereopods V–VII elongated (broad in G. sichuanensis); uropod III with no plumose setae (both rami with plumose setae on inner and outer margins).
Holotype: male (
The specific name is derived from the type locality; adjective.
Pereopods III and IV with long setae on posterior margins; epimeral plates blunt; uropod III inner ramus length less than half of outer ramus length, outer margin of outer ramus with few plumose setae.
(
Head. (Fig.
Gammarus kangdingensis sp. n., male holotype. A body (lateral view) B head C urosomites (dorsal view) D epimeral plates I–III E urosomites (lateral view) F antenna I G flagellum of antenna I H left mandible I inner face of article III of right palp J incisor of right palp K left maxilla L palp of right maxilla M upper lip.
Antenna I (Fig.
Antenna II (Fig.
Upper lip (Fig.
Mandible (Fig.
Lower lip (Fig.
Maxilla I (Fig.
Maxilla II (Fig.
Maxilliped (Fig.
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Pereopod III (Fig.
Pereopod IV (Fig.
Pereopod V (Fig.
Pereopod VI (Fig.
Pereopod VII (Fig.
Coxal gills (Figs
Pleon. Epimeral plates (Fig.
Pleopods I–III (Figs
Urosome. Urosomites I–III (Fig.
Uropod I (Fig.
Uropod II (Fig.
Uropod III (Fig.
Telson (Fig.
(
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Pereopods III–VII (Fig.
Oostegites (Fig.
Urosome. Uropod III (Fig.
This species was collected from a small stream at the foot of mountain, with weak water flow but many detritus.
Gammarus kangdingensis sp. n. resembles G. emeiensis Hou, Li & Koenemann, 2002 in pereopods III and IV having long setae on posterior margins; pereopods V–VII having marginal spines, but with few setae; and epimeral plates with blunt posterodistal corners. Gammarus kangdingensis sp. n. can be distinguished from G. emeiensis(G. emeiensis in parentheses) in antenna II peduncle having short setae along anterior and posterior margins, and calceoli (peduncle with long setae on anterior and posterior margins, calceoli absent); uropod III inner ramus 0.4 times the length of outer ramus (inner ramus 0.7 times the length of outer ramus); uropod III terminal article of outer ramus longer than adjacent spines (terminal article as long as adjacent spines).
Gamamrus kangdingensis sp. n. is similar to G. altus sp. n. in the shape of gnathopods I and II. It differs from G. altus sp. n. (G. altus in parentheses) in having pereopods III and IV with long setae on posterior margins (with a few short setae on posterior margins); and inner ramus of uropod III 0.4 times the length of outer ramus (0.3), inner margins of inner and outer rami with a row of plumose setae (with no plumose setae).
Holotype: male (
The specific name is derived from the type locality; adjective.
Antenna II with long setae along anterior and posterior margins of peduncle articles IV and V, calceoli absent; pereopods III and IV with long straight setae on posterior margin; inner ramus of uropod III less than half the length of outer ramus, both inner and outer rami with few marginal setae.
(
Head. (Fig.
Gammarus gonggaensis sp. n., male holotype. A head B epimeral plates C urosomites (lateral view) D urosomites (dorsal view) E maxilla II F maxilliped G incisor of left mandible H palp of left mandible I left maxilla I J palp of right maxilla I K incisor of right mandible L upper lip M lower lip.
Antenna I (Fig.
Antenna II (Fig.
Upper lip (Fig.
Mandible (Fig.
Lower lip (Fig.
Maxilla I (Fig.
Maxilla II (Fig.
Maxilliped (Fig.
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Pereopod III (Fig.
Pereopod IV (Fig.
Pereopod V (Fig.
Pereopod VI (Fig.
Pereopod VII (Fig.
Coxal gills (Fig.
Pleon. Epimeral plates (Fig.
Pleopods I–III (Fig.
Urosome. Urosomites I–III (Fig.
Uropod I (Fig.
Uropod II (Fig.
Uropod III (Fig.
Telson (Fig.
(
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Oostegites (Fig.
Urosome. Uropod III (Fig.
This species was collected from a small brook flowing under a large stone, forming a pool with an area of one square meter.
The new species of Gammarus gonggaensis sp. n. is similar to G. kangdingensis sp. n. in pereopods III and IV having long setae on posterior margins; and inner ramus of uropod III 0.4 times the length of outer ramus. Gammarus gonggaensis sp. n. can be distinguished from G. kangdingensis sp. n. (G. kangdingensis in parentheses) by antenna II peduncle having long setae along anterior and posterior margins, calceoli absent (peduncle with short setae, calceoli present); outer ramus of uropod III with a few plumose setae on inner margin, inner ramus with no plumose marginal setae (with a row of plumose setae on inner margins of inner and outer rami); terminal article of uropod III shorter than adjacent spines (longer than adjacent spines).
Gammarus gonggaensis sp. n. is similar to G. emeiensis Hou, Li & Koenemann, 2002 in antenna II peduncle with long setae along anterior and posterior margins, calceoli absent, and pereopods III and IV with long setae on posterior margins. It differs from G. emeiensis
Gammarus gonggaensis sp. n. differs from G. altus sp. n. (G. altus in parentheses) by anternna II peduncle with long setae, calceoli absent (with short setae, calceoli present); pereopods III and IV with long setae on posterior margin (with a few short setae); uropod III with plumose setae on inner margin of inner ramus (with no plumose setae), terminal article shorter than adjacent spines (longer than adjacent spines).
Holotype: male (
This specific name alludes to its living environment, living silt beside a polluted river; adjective.
Diagnosis. Antenna I accessory flagellum with three articles; antenna II calceoli present; pereopods III and IV with few setae on posterior margin; inner ramus of uropod III reaching 0.6 times the length of outer ramus, terminal article of outer ramus longer than adjacent spines, both inner and outer rami with few marginal setae.
(
Head. (Fig.
Antenna I (Fig.
Antenna II (Fig.
Upper lip (Fig.
Mandible (Fig.
Lower lip (Fig.
Maxilla I (Fig.
Maxilla II (Fig.
Maxilliped (Fig.
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Pereopod III (Fig.
Pereopod IV (Fig.
Pereopod V (Fig.
Pereopod VI (Fig.
Pereopod VII (Fig.
Coxal gills (Figs
Pleon. Epimeral plates (Fig.
Pleopods (Fig.
Urosome. Urosomites (Fig.
Uropod I (Fig.
Uropod II (Fig.
Uropod III (Fig.
Telson (Fig.
(
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Pereopods III–VII (Fig.
Oostegites (Figs
Urosome. Uropod III (Fig.
This species was collected along a riverside with altitude 4400 m, water polluted.
Gammarus limosus sp. n. is similar to G. altus sp. n. in antenna II having calceoli; pereopod V having few setae on posterior margin; and bases of pereopods V–VII elongated. Gammarus limosus sp. n. can be distinguished from G. altus (G. altus in parentheses) by pereopod III with few setae on posterior margin (merus with four groups of setae on posterior margin); epimeral plate III acute on posterodistal corner (blunt); and uropod III inner ramus longer than half of outer ramus length (inner ramus 0.3 times the length of outer ramus).
Gammarus limosus sp. n. is very similar to G. balcanicus Schäferna, 1922 (widespread in Europe). It differs from the latter by pereopods III–IV and uropod III having few setae; bases of pereopods VI and VII slender.
The species of the genus Gammarus recorded from the Tibetan Plateau can be classified into four groups based on morphological comparison: (1) G. lacustris group, is characterized by uropod III inner ramus longer than half of outer ramus length, both rami fringed with plumose setae, and includes five species: G. lacustris Sars, 1863, G. lasaensis Barnard & Dai, 1988, G. hongyuanensis Barnard & Dai, 1988, G. frigidus Hou & Li, 2004, and G. jaspidus Hou & Li, 2004; (2) cave species with no eyes, including G. abstrusus Hou, Platvoet & Li, 2006, and G. praecipuus Li, Hou & An, 2013; (3) G. sinuolatus Hou & Li, 2004 with long simple setae on uropod III; and (4) G. kangdingensis group is characterized by uropod III having a few simple or plumose setae, and includes G. emeiensis Hou, Li & Koenemann, 2002, G. sichuanensis Hou, Li & Zheng, 2002, G. glaber Hou, 2017, Gammarus altus sp. n., G. kangdingensis sp. n., G. gonggaensis sp. n., and G. limosus sp. n. A key to these species is presented as follows.
1 | Eyes absent | 2 |
– | Eyes presen | 3 |
2 | Pereopod III with long curled setae on posterior margin | G. abstrusus |
– | Pereopod III with short setae on posterior margin | G. praecipuus |
3 | Uropod III inner ramus longer than half of outer ramus, both rami with dense plumose setae | 4 |
– | Uropod III with some simple or plumose setae | 8 |
4 | Epimeral plates II and III very acute on posterodistal corners | 5 |
– | Epimeral plate II and III moderate on posterodistal corners | 6 |
5 | Gnathopod II propodus palm with three medial spines | G. lasaensis |
– | Gnathopod II propodus palm with one medial spine | G. lacustris |
6 | Urosomites dorsally elevated | G. jaspidus |
– | Urosomites dorsally non-humped | 7 |
7 | Uropod III inner ramus reaching 0.8 times the length of outer ramus | G. frigidus |
– | Uropod III inner ramus reaching 0.6 times the length of outer ramus | G. hongyuanensis |
8 | Uropod III only armed with long simple setae | G. sinuolatus |
– | Uropod III with simple or plumose setae | 9 |
9 | Pereopods III and IV merus and carpus with long setae on posterior margins | 10 |
– | Pereopods III and IV merus and carpus with a few short setae on posterior margins | 12 |
10 | Antenna II peduncle with long setae, calceoli absent | 11 |
– | Antenna II peduncle with short setae, calceoli present | G. kangdingensis sp. n. |
11 | Uropod III inner ramus reaching 0.4 times the length of outer ramus | G. gonggaensis sp. n. |
– | Uropod III inner ramus reaching 0.7 times the length of outer ramus | G. emeiensis |
12 | Uropod III inner ramus reaching 0.6 times the length of outer ramus, both rami with plumose setae | G. sichuanensis |
– | Uropod III with few plumose setae | 13 |
13 | Pereopods V–VII bases elongated | 14 |
– | Pereopods V–VII bases broad | G. glaber |
14 | Uropod III inner ramus longer than half of outer ramus | G. limosus sp. n. |
– | Uropod III inner ramus 0.3 times the length of outer ramus | G. altus sp. n. |
We are very grateful to Prof. Yifeng Chen (Institute of Hydrobiology, Chinese Academy of Sciences) for organizing the biota inventory in Tibet, to Drs Xianjin Peng, Jinzhong Fu, and Yuezhao Wang for their help in the field collection. We thank Prof. Cene Fišer, Prof. Kristine White, and Prof. Charles Oliver Coleman for their constructive comments. This study was supported by the Strategic Priority Research Program, Chinese Academy of Sciences (Category A, Tibet program), the National Science and Technology Basic Special (2014FY210700), the National Natural Sciences Foundation of China (NSFC-31772417), and CAS-SEABRI (Y4ZK111B01).