Samarangopus rotundifolius, Gao & Bu, 2023

Gao, Yan & Bu, Yun, 2023, Two new species of the genus Samarangopus and the first record of Eurypauropus japonicus (Arthropoda, Myriapoda, Pauropoda, Eurypauropodidae) from China, ZooKeys 1165, pp. 137-154 : 137

Samarangopus rotundifolius sp. nov.

Figs 5 , 6 , 7

Material examined.

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 .

Diagnosis.

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.

Description.

Adult body length (1.4-) 1.5 mm (n = 2); body brown to yellow (Fig. 5A ).

Head (Fig. 6B ) setae strongly reduced, with setae a 0 (33 μm) on dorsal surface and one pair of lateral setae l 1 (35 μm), other dorsal setae absent. Temporal organs rectangular in tergal view, length 0.8 of shortest interdistance, glabrous. Tiny pistils present laterally.

Antennae (Fig. 6D ). Chaetotaxy of segments 1-4: 2/2/3/4. Setae thin, tapering, striate, length of setae on segment 4: p = 45 μm, p ' = 28 (-30) μm, p ″ = 28 (-30) μm, u present and r absent. Third antennal segment with two normal setae and one rudimentary, pin-shaped setae. Tergal branch t cylindrical, 4.0 (-4.7) times as long as greatest diameter and 1.2 times as long as sternal branch s; the latter with distinct anterior indentation at level of F 2, 2.6 (-2.9) times as long as greatest diameter. Seta q similar to setae of segment 4, (25-) 30 μm, (0.7-) 0.9 times of the length of s. Globulus g with conical stalk, length of g (10 μm) (1.0-) 1.2 times as long as its greatest diameter; the latter 0.2 times of greatest diameter of t; 12 bracts, capsule spherical, diameter = 8 μm; stalk length 10 μm. Relative lengths of flagella (base segments included): F 1 = 100, F 2 = 46 (-48), F 3 = 84 (-92). Lengths of base segments: bs 1 = (26-) 28 μm, bs 2 = 10 μm, bs 3 = (18-) 20 μm. F 1 (2.9-) 3.1 times as long as t, F 2 and F 3 1.7 and 3.1 (-3.3) times as long as sternal branch s, respectively. Calyces of F 1 largest, those of F 2 and F 3 smaller, all subhemispherical.

Trunk. Setae of collum segment uniform, furcate, branches cylindrical and striate; both setae length 20 μm (Fig. 7A ). Appendages barrel-shaped; caps flat (Fig. 7A ). Sternite process broad, with anterior V-shaped incision. Tergites densely covered with protuberances of different shapes (Figs 5A, D-K , 6A, C, E ). Tergites II-V incompletely 2-partitioned posteriorly by a narrow, median, longitudinal groove; tergites I and VI entire (Fig. 6A ). Three main types of protuberances: large and round, leaf-shaped protuberances present on anterior margin of tergite I and lateral margins of tergites I-VI (Figs 5E-I, K , 6C ); small, candle-like protuberances each surrounded by a circular collar (Fig. 6C, E ); tiny, conical protuberances with circular collar (Fig. 6C, E ). Distribution pattern of candle-like protuberances as shown in Fig. 6A . Cuticle between these structures glabrous (Fig. 5D-K ). Anterior margin of tergites II-VI with 3-5 rows of regular coarse granules (Fig. 5E-I ). Pattern of marginal protuberances: tergite I: 40; tergite II: 1 small- T 1-10; tergite III: 1 small-7- T 2-7; tergite IV: 1 small-7 (8-9)- T 3-5; tergite V: 9- T 4-4 (3-4); tergite VI; 7 (8)- T 5-1. Length/width ratio of tergites: I = 0.59(-0.63), II = 0.38(-0.4), III = (0.45-)0.48, IV = (0.45-)0.48, V = 0.48, and VI = 0.59(-0.67).

Bothriotricha . All with short pubescence, T 1, T 2, T 4, and T 5 thin and with distal part curled (Fig. 7E ), T 3 shorter than others, with thicker axis, distal part spatulate and densely pubescent (Figs 5K , 7D ). Relative lengths of bothriotricha: T 1 = 100, T 2 = 120(-125), T 3 = 38(-45), T 4 = 60(-68), T 5 = 75(-77).

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 5C , 6F, G ). Tarsus of leg 1 with a single pubescent distal seta (Fig. 7B ). All legs with large main claw and small setose anterior secondary claw (Figs 7B, C ). Setae on coxa and trochanter of leg 9 thin (Figs 5L , 6H, I ), furcate, and striate, length of secondary branch 0.9 times of primary one on trochanter (Fig. 6H ), subequal on coxa (Fig. 6I ). Tarsi tapering, those of leg 9 (2.6-)3.0 times as long as greatest diameter; setae pubescent, tapering, pointed, proximal one (25-)30 μm, 0.4 times of the length of tarsus (65 μm) and 2.1(-2.5) times as long as distal one (12 μm) (Fig. 7C ). Anterior side of femur of leg 1 with a single conical pubescent plate (Fig. 7H ).

Male genital papillae (Fig. 7I ). Base segments cylindrical. Length of papillae = 75 μm, greatest diameter = 32 μm, length of seta = 25 μm. Proximal part of genital papillae subcylindrical, distal part conical, seta 0.3 times of length of papilla. Cuticle glabrous.

Pygidium. Tergum (Fig. 7G ). Setae pubescent: a 1 and a 2 short and clavate; a 3 straight, pointed. A median, unpaired linguiform, pubescent appendage framed by the paired seta a 1. Posterior margin with a pair of lateral triangular appendages situated between stae a 2 and a 3 of each side. Lengths of setae: a 1 = a 2 = 10 μm, a 3 = (24-)26 μm. Distances a 1- a 1 = 14 μm, a 1- a 2 = 8 μm, a 2- a 3 = 5 μm.

Sternum (Fig. 7F ). Setae pubescent: b 2 and b 3 thin, pointed. Seta b 1 thick, long, tapering, pointed. Lengths of setae: b 1 = 56(-60) μm, b 2 = 33 μm, b 3 = 20 μm. Distance b 1- b 1 = 50 μm, b 2- b 2 = 78 μm, b 1- b 2 = 26 μm, b 3- b 3 = 30 μm. Seta b 1 1.2 times as long as interdistance, b 2 1.3 times as long as distance b 1- b 2, b 3 0.7 times of interdistance. Posterior margin of sternum between b 1 slightly rounded. Between b 1 and anal plate, a pair of pubescent oval appendages present and a pair of lanceolate, glabrous styli st. st = 18 μm, st - st = 13 μm.

Anal plate (Figs 5B , 7F ) 1.6 times as long as broad, slightly tapering posteriorly; lateral margins with a pair of thin, diverging, pubescent branches, 0.5 times of the length of plate, distal part faintly inflated; posterior 1/2 of plate divided into two tapering branches by a deep, V-shaped incision, each branch with two apical appendages: a submedian short, straight, glabrous one and a stalked bladder of triangular shape in sternal view. Bladder 0.6 times of length of plate. Plate glabrous, bladder densely granulated.

Etymology.

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.

Distribution.

China (Zhejiang). Known only from the type locality.

Remarks.

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 (a 1 and a 2 short, clavate, pubescent, subequal in S. rotundifolius sp. nov. vs a 1 cylindrical and longer than clavate a 2, both glabrous in S. umbonifer , and a 1 and a 2 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 ).

Figures

Figure 5. 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 T 3 L setae on coxa (cx) and trochanter (tr) of leg 9. Scale bars: 100 μm (A); 20 μm (B-L).

Figure 6. 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).

Figure 7. Samarangopus rotundifolius sp. nov. (holotype) A collum segment, sternal view B tarsus of leg 1 C tarsus of leg 9 D T 3 E T 5 F sternum of pygidium and anal plate G tergum of pygidium H femur of leg 1 with appendage I male genital papillae. Scale bars: 20 μm.