Decapauropus arcuatilis, Scheller, Ulf, 2011

Scheller, Ulf, 2011, Pauropoda (Myriapoda) from Great Smoky Mountains National Park, U. S. A., with descriptions of four new species, Zootaxa 2962, pp. 36-48 : 38-39

Decapauropus arcuatilis n. sp.

Figs 1–11

Type locality. U.S.A., Tennessee, Great Smoky Mountains National Park, Sevier Co., Rainbow Falls.

Type specimens. Holotype: ad. 9(3), 4 May 1999, leg. E.C. Bernard & P.L. Jennings. — 1 specimen.

Diagnosis. D. arcuatilis n. sp. is well defined by the shape of the anal plate, with long cylindrical appendages which also are curved inwards, the T-shaped st and the downwards directed appendages of the collum segment. Its relationships can not be traced at present.

Derivation of name. From the Latin arcuatilis = shaped like a bow (referring to the appendages of the anal plate).

Description. Length. 0.68 mm.

Head (Fig. 1). Tergal setae striate, median and submedian setae somewhat clavate, lateral and sublateral ones cylindrical, a 3 in 2nd row and l -group setae tapering, pointed. Relative lengths of setae, 1st row: a 1=10; a 2=9; 2nd row: a 1=18, a 2=19, a 3=16; 3rd row: a 1=10, a 2=?; 4th row: a 1=14, a 2=21, a 3=13, a 4=17; l 1=14, l 2=18, l 3=?. Ratio a 1 /a 1 -a 1 in 1st row 0.5, 2nd and 3rd rows 0.8, 4th row 1.0. Temporal organs large, their length in tergal view 2.2 times as long as shortest interdistance; small pistill in posterior part. Head cuticle glabrous.

Antennae (Fig. 2). Segment 4 with at least 3 cylindrical striate blunt setae. Relative lengths of setae: p =10, p ʹ=15, p ʺ=3. Tergal seta p as long as tergal branch t. The latter fusiform, distally cut obliquely, 2.5 times as long as its greatest diameter and as long as sternal branch s, the latter 2.1 times as long as its greatest diameter and with its anterodistal corner truncate. Seta q as p ' of 4th segment, 0.7 of the length of s. Relative lengths of flagella (with base segments included) and base segments: F 1=100, bs 1=8, F 2=73, bs 2=5, F 3=75, bs 3=8. F 1 4.0 times as long as t, F 2 and F 3 2.9 and 3.0 times as long as s respectively, F 3 tapering. Distal calyces subhemispherical, largest on F 1, axis of flagella widened below calyx only in F 1. Globulus g subspherical, 9 bracts; capsule somewhat flattened. Diameter of g 0.9 of greatest diameter of t. Antennae glabrous.

Trunk (Figs 3, 4). Setae on collum segment (Fig. 3) furcate, branches cylindrical blunt, main branch striate, secondary branch rudimentary glabrous, sublateral setae 2.6 times as long as submedian setae. Sternite processes very thin anteriorly; appendages directed downwards. Collum segment glabrous.

Tergite I partly divided transversally, setae on tergites only partly studied. 4+4 setae on tergite I, 6+6 setae on II–IV, 4+2 on VI. Posterior setae on VI (Fig. 4) tapering, length 0.8 of interdistance and 1.7 times as long as pygidial setae a 1. Tergites glabrous.

Bothriotricha (Figs 5, 6). Axes thin straight, thickest in the middle of T 3 (Fig. 6). Relative lengths: T 1=100, T 2≈100, T 3=118, T 4=?, T 5=187. They have thin simple straight axes; pubescence consisting of simple straight hairs, oblique on most proximal parts, outwards erect, on distal 1/3 of T 1 (Fig. 5) and on T 2 branched erect hairs.

Genital papillae (Fig. 7). Conical, twice longer than greatest diameter, base segment well developed, seta 0.3 of the length of papilla.

Legs (Figs 8, 9). Legs short, setae on coxa and trochanter (Fig. 8) of leg 9 furcate, branches cylindrical blunt striate, secondary branch somewhat thinner than main branch. These setae on more anterior legs with rudimentary secondary branches. Tarsus of leg 9 (Fig. 9) straight tapering, 4.8 times as long as its greatest diameter. Setae striate, proximal seta tapering pointed, 0.3 of the length of tarsus and 2.2 times as long as cylindrical blunt distal seta. Cuticle of tarsus glabrous.

Pygidium (Figs 10, 11). Tergum. Posterior margin almost straight but with low broad lobe behind st. a -setae thin cylindrical blunt, a 1 straight diverging, a 2 and a 3 somewhat curved inwards, converging, st in sternal/tergal view straight converging T-shaped glabrous, distal broad part bent downwards. Relative lengths of setae: a 1=10, a 2=14, a 3=21, st ≈7. Distance a 1 -a 1 1.4 times as long as interdistance, distance a 1 -a 2 almost as long as distance a 2- a 3; distance st-st about 3 times longer than st and 0.7 of distance a 1 -a 1. Cuticle glabrous.

Sternum. Posterior margin between b 1 with low bulge below anal plate. Setae tapering, striate distally, b 1 blunt, b 2 pointed, their relative lengths (pygidial a 1 = 10): b 1 = 51, b 2=13. b 1 1.5 times as long as interdistance, b 2 0.8 of distance b 1- b 2.

Anal plate subquadrate, lateral margins concave, posterior corners each with a long cylindrical blunt appendage, this curved inwards and somewhat longer than plate itself. Plate and appendages glabrous.

FIGURES 1–11. Decapauropus arcuatilis n. sp., holotype (3). 1, head, submedian and right part, tergal view. 2, left antenna, sternal view. 3, collum segment, median and left part, sternal view. 4, tergite VI, right posterior corner and posteriomedian part. 5, T 1. 6, T 3. 7, genital papilla, lateral view. 8, seta on trochanter of leg 9. 9, tarsus of leg 9. 10, pygidium, posteriomedian and left posteror corner, sternal view. 11, anal plate, lateral view. Scale a: 5, 6, 9; b: 1, 4, 7, 8; c: 2, 3; d: 10, 11.