Decapauropus convexus, Scheller, 2009

Scheller, Ulf, 2009, New species of Pauropoda (Myriapoda) from Tasmanian temperate rainforests, Memoirs of Museum Victoria 66 (2), pp. 289-329 : 301-303

Decapauropus convexus sp. nov.

( Figs. 62–71 )

Material Examined. Holotype. Subad. 8 (female), Savage River, Loc. 1, (41°18.5'S, 145°16.3'E), soil core, 21.iv.1989 ( JD).

Paratype. Same data as holotype, 1 subad. 8 (male) .

Diagnosis. Decapauropus convexus shows superficial similarities in the shape of the T 3 and some pygidial characters with three species described by Remy: D. burghardti (1941) from France, D. pachypus (1948) from the Ivory Coast and D. zaianus (1952a) from Spain and Morocco. Good distinguishing characters in relation to burghardti are the tergal antennal branch 1.7–1.8 times longer than wide, not long and slender; the distal swelling of T 3 well delineated from the bothriotrix axis, axis not slowly becoming thicker distally; the posterior margin of the pygidial tergum has a shallow median indentation between the st, not a distinct rounded lobe. Decapauropus convexus can be distinguished from D. pachypus by the subspherical antennal globulus, not longish, the proportionately longer tarsi, by the posteromedian indentation in the pygidial tergum, not a triangular projection; and by the thin appendages of the anal plate, not thick and clavate. Distinguishing characters in relation to D. zaianus are the size of the antennal globulus, the length of which is about half of the length of sternal branch s, not 0.7 of that length, the shape of the distal swelling of the T 3 which is ovoid, not longish and subcylindrical; and the number of appendages of the anal plate, being two not four. D. convexus has some similarity too with D. insignis Remy, 1961 from India, but is distinguished especially by the much smaller antennal globulus, the proportionately shorter and thicker tergal antennal branch and by the the shape of the seta st which are curved and somewhat clavate, rather than straight and lanceolate.

Description. Length. -0.48(-0.50) mm.

Head.-Most tergal setae short, posterolateral ones of medium length, subcylindrical, densely annulate, blunt; relative lengths of setae (holotype only), 1st row: a 1 =10, a 2 =12; 2nd row: a 1 =10, a 2 =20, a 3 =12; 3rd row: a 1 =10, a 2 =13; 4th row: a 1 =10, a 2 =23, a 3 =a 4 =24; lateral group setae: l 1 =30, l 2 =24, l 3 =32. The ratio a 1 /a 1 -a 1 0.8 in 1st row, 0.6 in 2nd and 4th rows and 0.7 in 3rd row. Temporal organs large; their length in tergal view 1.2 times as long as their shortest distance apart; small aperture in posterior margin on a level with l 1. Head cuticle glabrous.

Antennae.-Segment 4 with four subcylindrical annulate setae, p, p' and p'' blunt, r pointed; their relative lengths: p =100, p' =44(-47), p'' =28(-30), r =(72-)75 and 80. The p''' rudimentary, u absent. Tergal seta p 1.6(-1.8) times as long as tergal branch t. The latter subcylindrical, (1.7-)1.8 times as long as its greatest diameter and 0.9 of the length of sternal branch s; that branch 1.7 times as long as its greatest diameter; anterodistal corner of s truncate. Seta q subcylindrical, annulate, blunt, 0.8(-0.9) of the length of s. Relative lengths of flagella (basal segments included) and basal segments: F 1 =100, bs 1 =7; F 2 =(41-)42, bs 2 =4; F 3 =(79-)81, bs 3 =7(-8). The F 1 4.9(-5.4) times as long as t, F 2 and F 3 (1.8-)1.9 and (3.6-)3.7 times as long as s respectively. Distal calyces small subhemispherical; distal part of flagella axes somewhat fusiform in F 1 and F 3, distinctly fusiform in F 2. Globulus g spherical with thin stalk, 1.2 times as long as wide; about nine bracts, capsule subspherical with somewhat flattened bottom; width of g 0.5 of the greatest diameter of t. Antennae glabrous.

Trunk. -Setae of collum segment cylindrical, striate, blunt, rudiments of secondary branches probably absent; sublateral setae 2.5 times as long as submedian ones; sternite process very narrow; appendages small with rounded caps; process and appendages glabrous.

Setae on tergites thin, cylindrical, annulate, blunt and of the same length on all tergites; 4+4 setae on tergite I, 6+6 on II–IV, 4+4 on VI. Relative lengths of bothriotricha (holotype only): T 1 =T 3 =100, T 2 =107, T 5 =135, with thin, simple, straight axes, T 3 with distal swelling. Pubescence hairs on T 5 and on proximal 1/3 of T 1, T 2, T 3 and on T 4 oblique; on T 1, T 2 and T 4 pubescence erect, sparse and whorled in outer 2/3; also on outer half of T 3 pubescence on distal swelling somewhat shorter than on the axis below it.

Genital papillae (paratype) small, conical, blunt.

Legs.-Setae on coxa and trochanter of leg 8 simple, cylindrical, striate, blunt; more anteriorly similar but coxal setae somewhat thicker than those on trochanter. Tarsus of leg 8 short, strongly tapering, (2.8)3.0 times longer than its greatest diameter. Setae cylindrical, blunt, proximal one annulate, distal one striate; proximal seta 0.2 of the length of tarsus and 0.6 of the length of distal seta. Tarsus with very delicate pubescence.

Pygidium. Tergum.-Posterior margin between st with two low submedian lobes separated by a shallow median indentation. Relative lengths of setae: a 1 =100, a 2 =93(96), a 3 =241(250), st =93(115), setae blunt, a 1 and a 2 subcylindrical, straight, annulate, the former pointing inwards, the latter pointing outwards; a 3 and st curved inwards, the former cylindrical and annulate, the latter somewhat clavate, striate, pointing inwards. Distance a 1 -a 1 (1.4)1.6 times as long as a 1; distance a 1 -a 2 (2.3)2.6 times as long as distance a 2 -a 3; distance st-st (2.1)2.2 times as long as st and 1.3(1.6) times as long as distance a

1

-a

1

. Cuticle almost glabrous.

Sternum.-Posterior margin between b 1 somewhat indented. Relative lengths of setae (a 1 =100): b 1 =463(490), b 2 =185(192). The b 1 cylindrical, densely striate, blunt; b 2 as a 3 of pygidial sternum. The b 1 (1.1)1.2 times as long as their distance apart; b 2 0.9 of distance b 1 -b 2. Cuticle sparsely pubescent. Anal plate subrectangular with slightly concave lateral margins and rounded posterolateral corners, 1.2 times as long as broad, glabrous; two parallel cylindrical and blunt appendages protrude backwards from posterior part of sternal side; length of appendages 0.5 of the length of the plate.

Etymology.-From Latin convexus = well rounded (at the top, posterior part of the anal plate).

Distribution in Tasmania. Known from a single site in north-eastern Tasmania.

Figures

Figs. 62–71. Decapauropus convexus sp.nov., holotype: 62, head, median and right part, tergal view; 63, temporal organ, posterior part, lateral view; 64, left antenna, sternal view; 65, collum segment, median and left part, sternal view; 66, T; 67, T; 68, seta on trochanter of 9th pair of 1 3 legs; 69, tarsus of 9th pair of legs; 70, pygidium, posterior and left part, sternal view; 71, anal plate, lateral view. Scale line a for figures 62, 63, 66, 67; b for figures 64, 65, 68, 69; c for figures 70, 71.