Psammopauropus macrospinus, Bu, 2020

Bu, Yun, 2020, A remarkable new genus and species of Hansenauropodidae (Myriapoda Pauropoda) from the seashore of Hainan Island, China, Zootaxa 4803 (2), pp. 373-380 : 375-379

Psammopauropus macrospinus new species

Figures 3–26

Material examined: Holotype, male with 9 pairs of legs (slide no. HN-SY-PA2017054) ( SNHM), China, Hainan Province, Sanya City, flotation of sand and debris from seashore of Sanya Bay , 18°18’N / 109°22’E, 20-X-2017, coll. Yun Bu. Paratypes, 4 females, in alcohol, same locality data as holotype .

Diagnosis. As for the genus.

Description. Body slender, with short legs, holotype length 1.23 mm ( Figs. 11, 12 ). Head ( Figs. 3 , 13 ). Dorsal setae short, rudimentary and bud-shaped, medial and lateral setae cylindrical, striate. Relative lengths of setae, 1 st row: a 1 = 10, a 2 = 10; 2 nd row: a 1 = 10, a 2 = 43, a 3 = 40; 3 rd row: a 1 = 10, a 2 = 17; 4 th row: a 1 = 10, a 2 = 40, a 3 = 16, a 4 = 45; lateral group setae l 1 = 40, l 2 = 37, l 3 = 40; the ratio a 1 / a 1 – a 1 in 1 st row 0.6, 2 nd row 0.3, 3 rd row 0.4 and 4 th row 0.4. Temporal organs oval in dorsal view, their length 1.4 times as long as their shortest distance apart ( Fig. 13 ). Pistil present. Head cuticle faintly granular. Antennae ( Figs. 4 , 16 ). Antennal segments 1–3 with 2, 2, 3 short bud-shaped pubescent setae, respectively. Antennal segment 4 with four cylindrical setae; relative lengths of setae: p = 10, p ’ = 8, p ’’ = 5, r = 4; tergal seta p 1.5 times as long as tergal branch t; the latter cylindrical, 1.6 times as long as its greatest diameter and 1.3 times as long as sternal branch s, which itself is 1.3 times as long as its greatest diameter. Seta q cylindrical, striate, 1.2 times as long as s. Relative lengths of flagella (base segments included) and base segments: F 1 = 100, bs 1 = 9; F 2 = 38, bs 2 = 6; F 3 =89, bs 3 = 8. F 1 6.5 times as long as t, F 2 and F 3 1.9 and 4.5 times as long as s respectively. Distal calyces spherical; distal part of flagella axes slightly fusiform. Globulus g 1.3 times as long as wide; about 10 bracts, capsule subspherical; width of g 0.6 of the greatest diameter of t. Antennae glabrous. Trunk. Setae on collum subcylindrical, striate; sublateral setae length 25 μm, 3.1 times as long as submedian setae; sternite process triangular, pointed; appendages narrowing distally and with flat caps ( Figs. 8 , 14 ). Tergite I entire, with 4+4 short clavate setae ( Fig. 15 ); Tergites II–V transversally divided into a protergite and a metatergite ( Figs. 17–20 ), 6+6 short clavate setae on II–IV, 6+4 short setae on V; Tergite V with two symmetrical sclerotized patches posteriorly ( Figs. 11 , 20 ); Tergite VI entire, with one sclerotized and thickened middle patch of cuticle, 4+2 cylindrical setae, posterior seta 28 μm ( Fig. 21 ). Tergites I–V coarse granulated and tergite VI pubescent. Bothriotricha. Relative lengths: T 1 = 100, T 2 = 107, T 3 = 82, T 4 =108, T 5 = 128. T 1, T 2, T 4 and T 5 slim and long, with dense pubescence on shafts ( Figs. 7 ; 17–21 ). T 3 spatulate with short dense pubescence on axes and coarse granule on distal part ( Figs. 7 , 19 ). Legs. All legs short, leg 1 and 9 5-segmented, others 6-segmented ( Figs. 12 , 22 ). Setae on coxa and trochanter of all legs cylindrical, annulate ( Fig. 22 ), 13 and 15 μm long on leg 9 respectively. Tarsi 1–8 with globular distal seta only ( Fig. 5 ). Tarsus of leg 9 short, 30 μm in length, cylindrical, 2.1 times as long as its greatest diameter ( Fig. 6 ), proximal seta cylindrical, annulate, 12 μm in length; distal globular, 13 μm in length, pubescent; their lengths about 0.4 of the tarsal length. Cuticle of tarsus glabrous. Pygidium. Tergum. Posterior margin undulate. Relative lengths of setae: a 1 = 10, a 2 = 10, a 3 = 17.5 st = 9. Setae distinctly differentiated, a 1 as large spines, a 2 and a 3 slender and pubescent ( Figs. 9 ; 24, 25 ), st large , globular shaped and pubescent ( Figs. 10 ; 26 ). Distance a 1 – a 1 0.75 of length of a 1; distance a 1 – a 2 1.7 times as long as a 2 – a 3; distance st–st 1.4 times as long as st and 1.7 times as long as distance a 1 – a 1. Sternum ( Figs. 10 ; 24 ). Posterior margin with deep indention between b 1. Relative lengths of setae (a 1 =10): b 1 = 19, b 2 =14. All setae slender, striate. Distance b 1 – b 1 0.9 of length of b 1; distance b 1 – b 2 1.6 times as long as b 2. Male genital papillae ( Fig. 23 ) glabrous, rounded distally, 1.6 times as long as greatest diameter; seta 0.5 of the length of papilla. Anal plate shown in Figs. 10 and 24 , small, pubescent and complicated, basally divided into two triangular parts; with two pairs of globular appendages, inner one tiny and smaller than outer one.

Etymology. The species name “ macrospinus ” refers to the two large spines on the pygidium.

Distribution. China (Hainan Island). Only known from the type locality.

Figures

FIGURES 3–10. Psammopauropus macrospinus sp. n. holotype. 3, head, right side, dorsal view; 4, antenna, dorsal view; 5, tarsus of leg 1; 6, tarsus of leg 9; 7, T3 and T5; 8, collum; 9, tergum of pygidium; 10, sternum of pygidium. Scale bars: 20 μm.

FIGURES 11–16. Psammopauropus macrospinus sp. n. holotype. 11, habitus, dorsal view; 12, habitus, ventral view; 13, head, dorsal view—temporal organs are large oval structures; 14, collum; 15, tergite I; 16, antenna. Scale bar: 100 μm (11–12); 20 μm (13–16).

FIGURES 17–26. Psammopauropus macrospinus sp. n. holotype. 17–20, tergites II–V, right side, dorsal view; 21, tergite VI and pygidium; 22, leg 5; 23, male genital papillae; 24, sternum of pygidium, shows anal plates; 25, tergum of pygidium, shows spines; 26, pygidium, shows globular seta st. Scale bars: 20 μm.