Research Article |
Corresponding author: Yun Bu ( buy@sstm.org.cn ) Academic editor: Pavel Stoev
© 2023 Yan Gao, Yun Bu.
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:
Gao Y, Bu Y (2023) Two new species of the genus Samarangopus and the first record of Eurypauropus japonicus (Arthropoda, Myriapoda, Pauropoda, Eurypauropodidae) from China. ZooKeys 1165: 137-154. https://doi.org/10.3897/zookeys.1165.102936
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Two new species, Samarangopus testudineus sp. nov. from Hunan, South China and S. rotundifolius sp. nov. from Zhejiang, East China, are described and illustrated. Samarangopus testudineus sp. nov. is characterized by unusual testudinal patterns on the dorsal side of the body and well-differentiated marginal protuberances on tergites. Samarangopus rotundifolius sp. nov. features large, round, leaf-shaped marginal protuberances and small, candle-like dorsal protuberances on tergites. Both of these species are compared to similar species in detail. In addition, Eurypauropus japonicus Hagino & Scheller, 1985 is newly recorded from China.
Hunan, pauropod, protuberances, setae, taxonomy, Zhejiang
Pauropoda are tiny arthropods living in litter or soil. They are among the least-known myriapods in the world, with only about 990 species described worldwide (https://www.itis.gov/, accessed May 2023). The Chinese pauropod fauna is poorly known, with only 50 species reported so far (
The family Eurypauropodidae Ryder, 1879 currently includes about 70 valid species (https://www.itis.gov/). It is characterized by a flattened body, strongly sclerotized tergites with a coarsely ornamented surface, modified setae, and specialized marginal protuberances (
All pauropods were obtained by extraction of soil and litter samples from broad-leaf or mixed forests using Berlese–Tullgren funnels. Specimens were sorted under a stereomicroscope and preserved in 80% alcohol. They were mounted on slides using Hoyer’s solution and dried in an oven at 50 °C. Observations were performed under a phase contrast microscope (Leica DM 2500). Photos were taken using a digital camera (Leica DMC 4500). Line drawings were made using a drawing tube. All specimens are deposited in the collection maintained by the Shanghai Natural History Museum (SNHM), Shanghai, China.
Abbreviations used in the descriptions follow
Family Eurypauropodidae Ryder, 1879
Samarangopus jacobsoni (Silvestri, 1930).
Holotype , female adult with 9 pairs of legs (slide no. HN-SHS-PA2020035) (SNHM), China, Hunan Province, Shaoyang City, Xinning County, Shunhuangshan Nature Reserve, extracted from soil samples in mixed forest, elev. 900 m, 26°23'N, 111°00'E, 4-IX-2020, coll. C.W. Huang. Paratype, 1 juvenile with 8 pairs of legs (slide no. HN-NS-PA2020036), Hunan Province, Shaoyang City, Chengbu County, Nanshan National Park, extracted from soil samples in mixed forest, elev. 1200 m, 26°18'N, 110°29'E, 8-IX-2020, coll. C.W. Huang.
Samarangopus testudineus sp. nov. is characterized by testudinal pattern (tortoise shell-like) on the dorsal side of the body, marginal protuberances on tergites well-differentiated into four kinds of shapes, and one pair of sausage-shaped bladders on the anal plate.
Adult body length 1.95 mm; body dark brown in alcohol, brown to reddish after mounted on slides, dorsally with distinct testudinal pattern (Figs
Samarangopus testudineus sp. nov. (holotype) A tergites I–VI, showing the testudinal pattern B right antenna, tergal view (arrow indicates pin-shaped seta) C marginal leaf-shaped protuberance, sternal view D left posterior corner of tergite I, tergal view E left posterior corner of tergite IV, sternal view (arrow indicates tiny rod-shaped protuberance) F ridges on the tergite IV, lateral view on slide. Scale bars: 100 μm (A); 20 μm (B–F).
Head setae strongly reduced, dorsally with setae a0 and one pair of lateral setae l1, other setae absent. Temporal organs rectangular in tergal view, length 0.7 of shortest interdistance, glabrous. Tiny pistils present laterally.
Antennae
(Fig.
Trunk. Collum segment not clearly visible. Tergites with testudinal patterns limited by different kind of structures and protuberances (Figs
Samarangopus testudineus sp. nov. (holotype) A anterior margin of tergite I B left posterior corner of tergite I C hind margin of tergite I D ridges on tergite IV E left side of tergite II (black arrow indicates tiny rod-shaped protuberance, white arrow indicates round leaf-shaped) F marginal protuberances on tergite II, sternal view G tergite IV, left side (arrow indicates the same as in E). Scale bars: 20 μm.
Bothriotricha. All with short pubescence, T1, T2, T4, and T5 thin and with blunt apex (Fig.
Legs. All legs 5-segmented. Setae on coxa and trochanter of leg 9 similar to each other; thin, glabrous, bifurcate, with length of secondary branch 0.6 times of primary one (Fig.
Pygidium. Tergum
(Fig.
Sternum
(Fig.
Anal plate
(Fig.
From the masculine Latin word “testudineus” meaning “with the pattern of tortoise shell” that refers to the testudinal pattern on the tergites of the new species.
China (Hunan). Known only from the type locality.
Samarangopus testudineus sp. nov. can be easily distinguished from all other congeners by the unique dorsal testudinal pattern on the body and the shape of protuberances on the body, as well as the anal plate. The dark-brown ridges composed of different structures and protuberances on tergites were only observed in S. amplissimus Scheller, 2009 from Indonesia, but their patterns are apparently different between the two species (vertically located on posterior part of tergites I–V in S. testudineus sp. nov. vs located on anterior part of tergite I and lateral part of tergites II–VI, curved). The species also differ in the shapes of marginal protuberances on tergite I (differentiated in three kinds, with pattern 1 tiny–3 large–41 small–3 large–1 tiny in S. testudineus sp. nov. vs with 38 similar leaf-shaped, large protuberances in S. amplissimus), the shape of leaf-shaped protuberances (with reticulations in S. testudineus sp. nov. vs without reticulations in S. amplissimus), the shape of globulus g on antenna (1.4 times as long as greatest diameter in S. testudineus sp. nov. vs 2.4 times as long as greatest diameter in S. amplissimus), the shape of the setae on the pygidial sternum (cylindrical in S. testudineus sp. nov. vs slender and pointed in S. amplissimus), and the anal plate (with sausage-shaped, granulated bladders in S. testudineus sp. nov. vs with ovoid, pubescent bladders in S. amplissimus).
Holotype , male adult with 9 pairs of legs (slide no. ZJ-GTS-PA2012011) (SNHM), China, Zhejiang Province, Gutian Mountain, extracted from soil samples in the broad-leaved forest, Alt. 1000 m, 29°16'N, 118°06'E, 11-IV-2012, coll. Y. Bu. Paratype, 1 male adult with 9 pairs of legs (slide no. ZJ-GTS-PA2012012), same data as holotype. Non-type specimens, 2 juveniles with 6 pairs of legs (slides no. ZJ-GTS-PA2012028, ZJ-GTS-PA2012029), 1 juvenile with 5 pairs of legs (slide no. ZJ-GTS-PA2012030), same data as holotype.
Samarangopus rotundifolius sp. nov. is characterized by large, round, leaf-shaped protuberances on the anterior margin of tergite I and the lateral margins of tergites I–VI, small, candle-like protuberances with distal, flame-like structures and entire protuberance surrounded by a circular collar mainly situated in the caudal halves of all tergites, trifurcated setae on coxa and trochanter of leg 1, and a pair of triangular bladders on the anal plate.
Adult body length (1.4–) 1.5 mm (n = 2); body brown to yellow (Fig.
Samarangopus rotundifolius sp. nov. (holotype) A habitus, tergal view, on slide B anal plate C setae on coxa (cx) and trochanter (tr) of leg 1 D tergite I E tergite II, right side F tergite III, right side G tergite IV, right side H tergite V right side I tergite VI and pygidum J middle part of tergite II, showing protuberances K left side of tergite IV, with round, leaf-shaped protuberance and T3 L setae on coxa (cx) and trochanter (tr) of leg 9. Scale bars: 100 μm (A); 20 μm (B–L).
Head
(Fig.
Samarangopus rotundifolius sp. nov. (holotype) A tergites I–VI, showing the pattern of candle-shaped protuberances on the body B head, tergal view (to–temporal organ; arrows indicate pistils) C left posterior corner of tergite I D right antenna, tergal view (arrow indicates pin-shaped seta) E middle part of tergite II, with candle-like and conical protuberances F seta on coxa of leg 1 G seta on trochanter of leg 1 H seta on the coxa of leg 9 I seta on the trochanter of leg 9. Scale bars: 100 μm (A); 20 μm (B–I).
Antennae
(Fig.
Trunk. Setae of collum segment uniform, furcate, branches cylindrical and striate; both setae length 20 μm (Fig.
Bothriotricha. All with short pubescence, T1, T2, T4, and T5 thin and with distal part curled (Fig.
Legs. All legs 5-segmented. Setae on coxa and trochanter of leg 1 both trifurcated, striate, two short branches 0.2 times of primary one, with middle one glabrous and lateral one pubescent (Figs
Male genital papillae
(Fig.
Pygidium. Tergum
(Fig.
Sternum
(Fig.
Anal plate
(Figs
From the Latin “rotundus” = “round” and “folium” = “of leaf”. The species name “rotundifolius” is masculine that refers to the round, leaf-shaped protuberances on the margin of tergites in the new species.
China (Zhejiang). Known only from the type locality.
Samarangopus rotundifolius sp. nov. can be easily distinguished from all other congeners by the round, leaf-shaped marginal protuberances on its tergites. It is similar to S. umbonifer Scheller, 1995 and S. doiinthanonaeus Scheller, 1995 from Thailand in the shape of the anal plate and setae on the pygidium. They differ in the shape of marginal protuberances on tergite I (all rounded leaf-shaped in S. rotundifolius sp. nov. vs fungiform at anterior and anterolateral margins and some wedge- to leaf-shaped at posterolateral corners in S. umbonifer, and all wedge- to leaf-shaped in S. doiinthanonaeus), the shape of setae on the collum segment (furcate and the secondary branch about half length of primary one in S. rotundifolius sp. nov. vs furcate with a rudimentary secondary branch in S. umbonifer and S. doiinthanonaeus), shape of setae on tergum of pygidium (a1 and a2 short, clavate, pubescent, subequal in S. rotundifolius sp. nov. vs a1 cylindrical and longer than clavate a2, both glabrous in S. umbonifer, and a1 and a2 both cylindrical, pubescent in S. doiinthanonaeus), and the shape of the plate on the anterior side of the femur of leg 1 (conical in S. rotundifolius sp. nov. vs linguiform and slightly pointed in S. umbonifer, linguiform and round in S. doiinthanonaeus).
Eurypauropus spinosus Ryder, 1879.
Fourth antennal segment with four well-developed setae; globulus g of ventral antennal branch long-stalked; third antennal segment with a globulus g2; setae of tergites inserted in rounded crater-shaped structures; first and last pair of legs 5-segmented, other pairs 6-segmented; anal plate V-shaped with straight lateral margins; interdistance of pygidial setae a1 nearly twice as long as distance a2–a3 (
Nearctic, Palaearctic.
1 female adult with 9 pairs of legs (slide no. ZJ-GTS-PA2012023), China, Zhejiang Province, Gutian Mountain, extracted from soil samples in broad-leaved forest, alt. 1000 m, 29°16'N, 118°06'E, 27-III-2013, coll. Y. Bu.
Eurypauropus japonicus is characterized by the shape of the anal plate with one pair of small, pointed lateral appendages, subcylindrical setae b2 on the sternum of the pygidium, tergites with large, curved, ciliated spines and small, nipple-shaped tubercles with conical bases.
Length 1.28 mm, light brown (Fig.
Eurypauropus japonicus Hagino & Scheller, 1985 (Chinese specimen) A habitus, tergal view, on slide B right antenna, tergal view C posterior corner of tergite VI, pygidium and anal plate (arrow indicates the big spine), sternal view D antennal segment III, showing globulus g2 E Tergite II–IV F tergites I G tergite II, middle part H tergite III, middle part I tergite IV, middle part J tergite V K tergite IV, left side, showing the marginal protuberances and T3 L tergite V, left side, showing marginal protuberances. Scale bars: 100 μm (A); 20 μm (B–L).
Antennae
(Fig.
Trunk. Setae of collum segment not clearly seen. Tergites densely covered with two types of protuberances: large, curved, evenly distributed, spiniform protuberances and small, nipple-shaped tubercles with conical bases (Fig.
Bothriotricha. T1 and T2 with thin axes and glabrous proximal parts, medial part with erect, short pubescence, and distal 4/5 with branched hairs arranged in whorls. T3 shorter than others, club-like, and glabrous (Fig.
Legs. Legs 1 and 9 both 5-segmented, others 6-segmented. Setae on coxa and trochanter of leg 9 similar to each other, bifurcate, densely annulated, length of secondary branch subequal to primary one. Tarsus of leg 9 thick, tapering, 1.6 times as long as greatest diameter; 2 tergal setae and 1 sternal setae pointed, glabrous; proximal seta length 23 μm, 0.4 times of the length of tarsus (52 μm) and 1.9 times as long as distal seta (13 μm). Main claw 27 μm, 0.5 times as long as tarsus, anterior accessory claw tapering (17 μm). Cuticle of tarsus with minute granules. Tarsus of leg 1 with 1 tergal seta (13 μm) and 1 sternal seta (15 μm), both glabrous and pointed, main claw 27 μm and accessory claw 10 μm.
Pygidium. Tergum.
Posterior margin round. Seta a1 short, cylindrical, pubescent; a2 and a3 spiniform, glabrous; a3 sharply pointed (Fig.
Sternum
(Fig.
Anal plate. 1.1 times as long as broad; narrow at base; distal part of plate cleft by narrow, V-shaped incision, depth about half of plate length, incision forming two posterior branches, each carrying two pairs of appendages: submedian pair leaf-shaped, about half length of plate, 2.1 times as long and wide; lateral ones short, pointed and pubescent. Plate glabrous, distal appendages pubescent (Fig.
China (Zhejiang), Japan (Honshu, Kyushu).
Eurypauropus japonicus was originally described and known from Honshu and Kyushu, Japan (
The genus Samarangopus includes 40 species distributed in the Palearctic, Ethiopian, and Oriental regions (
The genus Eurypauropos includes about 10 species recorded from USA and Japan (
We thank C.W. Huang for the collection of specimens from Hunan province. We appreciate Dr Nerivania Nunes Godeiro for the linguistic corrections of the manuscript and Dr Yasunori Hagino (Japan) for kindly posting the reprints of his Pauropoda article. Special thanks are given to Dr Nikolaus Szucsich (Austria), Dr Derek Hennen (USA), and an anonymous reviewer for their valuable comments in review of the manuscript. This research is supported by the National Natural Science Foundation of China (no. 32170471).
No conflict of interest was declared.
No ethical statement was reported.
No funding was reported.
Conceptualization: YB. Funding acquisition: YB. Investigation: YG, YB. Methodology: YB. Project administration: YB. Validation: YB, YG. Writing – original draft: YG. Writing – review and editing: YG, YB.
All of the data that support the findings of this study are available in the main text or Supplementary Information.