Samarangopus canalis Scheller, 2009, new record to China

Bu, Yun, 2020, Study on the Pauropoda (Myriapoda) from Tibet, China - Part II: New species and new record of the genus Samarangopus, ZooKeys 927, pp. 53-64 : 53

Samarangopus canalis Scheller, 2009, new record to China Figure 4

Material examined.

1 male adult with 9 pairs of legs (slide no. XZ-PA2015053) (SNHM), 1 female adult with 9 pairs of legs (slide no. XZ-PA2015055) (SNHM), China, Tibet, Motuo county, Dexing town, extracted from soil samples of broad-leaf forest, Alt. 1100 m, 29°40'N, 95°26'E, 3-XI-2015, coll. Y. Bu.

Diagnosis.

Samarangopus canalis Scheller, 2009 is characterized by the peculiar shape of distal part of male genital papillae which forming an anteriorly open furrow and the ovoid posterior appendages of the anal plate.

Description of new materials.

Length 0.90 mm (n = 2), yellow to brown in color (Fig. 4A ). Head covered by tergite I and chaetotaxy not studied in detail.

Antennae (Fig. 4B ). Chaetotaxy of segments 1-4: 2/2/2/3. Setae thin, cylindrical, striate, length of seate on segment 4: p = 16-18 μm, p ' = 15-17 μm, p' ’’ = 10-12 μm; p' ’’’ rudimentary; u and r absent. Tergal branch t fusiform, 2.9-3.2 times as wide as greatest diameter and 1.2-1.3 times as long as sternal branch. Sternal branch s with distinct anterior indentation at level of F 2, 1.8-2.0 times as long as greatest diameter, anterodistal corner distinctly truncate. Seta q similar to setae of segment IV, 15-16 μm, 0.8 of the length of s. Globulus g with conical stalk, length of g (10-12 μm) 1.7-2.0 times as long as greatest diameter; the latter 0.2-0.3 of greatest diameter of t; 9-10 bracts, capsule spherical, diameter = 3 μm; stalk length 5 μm. Relative lengths of flagella (base segments included): F 1 = 100, F 2 = 35-40, F 3 = 82-84. Lengths of base segments: bs 1 = 15-18 μm, bs 2 = 7-8 μm, bs 3 = 13-14 μm. F 1 3.3-3.7 times as long as t, F 2 and F 3 1.6-1.9 and 3.6-3.9 times as long as sternal branch s. Calyces of F 1 largest, conical, those of F 2 and F 3 smaller, subhemispherical.

Trunk. Setae of collum segment similar, furcate, branches tapering, pointed; main branch cylindrical, annulated, blunt, secondary branch 0.3 of the length of primary branch, glabrous (Fig. 4C ); submedian seta 0.8-0.9 of the length of sublateral seta. Sternite process broad and low, with anterior incision and rounded pubescent lobes. Appendages subcylindrical, caps flat. Process and appendages glabrous. Tergites densely covered with protuberances. Anterior and lateral margins of tergites with a single row of large protuberances (Fig. 4A, E, F ). Posteriomedian margin of tergites with comb-shaped ornaments (Fig. 4G ). Number of marginal protuberances: I, 26-29; II, 1 small- T 1-1 small-9; III, (5-6)- T 2-l small-6; IV, (6-7)- T 3-l small-5; V, 8- T 4-l small-3; VI, 6- T 5-l. Length/width ratio of tergites: I = 0.67-0.72, II = 0.34-0.36, III and IV = 0.42-0.45, V = 0.44-0.46, VI = 0.56-0.59.

Bothriotricha . All with thin axes, glabrous proximal parts, distally with minute pubescence, T 1, T 2, T 4 and T 5 curled distally, T 3 shorter than others, with thicker axis and terminated by an ovoid swelling (Fig. 4E ). Relative lengths of bothriotricha: T 1 = 100, T 2 = 94, T 3 = 56, T 4 = 94, T 5 = 100.

Genital papillae (Fig. 4D ). Base segments in the shape of a truncated cone, relatively long, length of papillae 65 μm, greatest diameter 20 μm, seta 55 μm. Proximal part of papillae strongly tapering outward, distal 3/4 forming an anteriorly open furrow. Papilla 3.3 times as long as greatest diameter, seta 0.8 of length of papilla. Cuticle glabrous. Coxal seta of leg 2 in male with long base, furcate, primary branch cylindrical, annulated, secondary branch short, tapering, pointed, glabrous.

Legs. All legs 5-segmented. Setae on coxa and trochanter of leg 9 similar to each other, thin, furcate, densely annulated, length of secondary branch 0.7-0.8 of primary one (Fig. 4I ). On more anterior legs these setae with rudimentary secondary branches (Fig. 4H ). Tarsi of leg 9 short and thick, tapering, 2.2 times as long as greatest diameter; tergal setae pointed, glabrous. Proximal seta length 9-10 μm, 0.3 of the length of tarsus (33 μm) and 1.2-1.3 times as long as distal seta (7-8 μm). Cuticle of tarsus with minute granules. No proximal seta on tarsus of leg 1. All legs with large main claw and small setose anterior secondary claw, the former on those of leg 9 0.5 of tarsi. Anterior side of femur of leg 1 with one blunt appendage with short pubescence, length = 4-5 μm (Fig. 4H ).

Pygidium. Tergum. Posterior margin with two narrow, digitiform posterior directed processes protruding from between setae a 2 and a 3. Setae glabrous, a 1 straight, a 2 clavate, short, a 3 slender and long; st long and leaf-shaped, 10-11 μm. Two semicircle plates close to st with dense pubescence. Lengths of setae: a 1= 5 μm, a 2 =6-8 μm, a 3 = 15 μm. Distance a 1- a 1=7-9 μm, a 1- a 2=5-7 μm, a 2- a 3=4-5 μm, st - st =10 μm.

Sternum. Posterior margin between b 1 almost straight. Setae thin, tapering, pointed, distal part of b 1 annulated, b 2 and b 3 striated. Lengths of setae: b 1= 32 μm, b 2=23-25 μm, b 3= 11-13 μm. Distances b 1- b 1= 28-30 μm, b 2- b 2= 50-53 μm, b 1- b 2= 21-23 μm, b 3- b 3= 23-25 μm. b 1 1.1 times as long as interdistance, b 2 1.0-1.2 of distance b 1 - b 2, b 3 0.55 of interdistance.

Anal plate. 1.2 times as long as broad; lateral margins straight anteriorly, concave posteriorly; distal part of plate cleft by narrow U-shaped incision, depth 0.3-0.4 of the length of plate, incision forming two posterior branches with subparallel sides, each with two appendages: a submedian short, straight, glabrous one and a thin folioform stalked appendage protruding backward. Folioform appendage about 0.6 of length of plate. Plate glabrous, distal appendages with somewhat granular surface.

Distribution.

China (Tibet), Indonesia (Sulawesi).

Remarks.

Samarangopus canalis was originally described and only known from Sulawesi Island, Indonesia ( Scheller 2009). The anal plate, the male genital papillae as well as the protuberances on the body of Chinese specimens are nearly the same with S. canalis which proved the species identity. The main difference is that the posterior branches of anal plate of Chinese specimens each have two appendages, with a submedian, short, straight, glabrous appendage present, but absent in the types from Sulawesi. Other minor differences are the body size, numbers of protuberances on the body and the lengths of setae, bothriotricha, and flagella, which might belong to the variances between populations of different localities. In addition, the anal plate of S. canalis and S. zhongi sp. nov. both having two appendages, but the shape of posterior one is different: bladder is triangular in S. zhongi sp. nov. but folioform in S. canalis .

Figures

Figure 4. Samarangopus canalis Scheller, 2009 (Chinese specimens) A habitus, tergal view B left antenna, tergal view C collum segment, sternal view D male genital papillae E right margin of tergite IV, show T 3 F right anterolateral corner of tergite II, tergal view G posteriomedian margin of Tergite I H leg 1 I setae on coxa and trochanter of leg 9. Scale bars: 100 μm (A); 20 μm (B-I).