Identity of the millipede genus Pyrgodesmus Pocock, 1892, the type genus of the family Pyrgodesmidae (Diplopoda, Polydesmida)
Author
Golovatch, Sergei I.
text
Zootaxa
2021
2021-11-18
5068
4
572
578
journal article
3390
10.11646/zootaxa.5068.4.6
79b5ca84-737c-4722-9994-9f5cdefbebb3
1175-5326
5709642
E4A3743F-14A9-4292-AC55-56B7E7F0905C
Pyrgodesmus obscurus
Pocock 1892
Figs 1–8
Pyrgodesmus obscurus
Pocock, 1892: 155
, plate 2, figs 1–1b (D).
Pyrgodesmus obscurus
—
Attems, 1914: 174
(R); 1936: 246 (R); 1940: 261, fig. 370 (D, R);
Jeekel, 1971: 350
(R, M);
De Zoysa
et al.
, 2016: 477
(R, M);
Aswathy
et al.
, 2021: 373
(D, R).
Remark.
As noted above, the original description of this species was rather superficial and incomplete, especially as regards the crucial gonopodal structure (
Pocock 1892
).
Brief redescription.
Body with 20 rings (19+T), length
ca
10.5 mm
. Coloration mostly dark grey-brown with contrasting pallid legs, tegument heavily coated with an earth crust (
Figs 4–6
).
Head fully covered from above by a flabellate anterior brim of a dome-shaped collum, the latter with 5+5 equal, distinct, rounded lobulations at anterior margin. Antennae C-shaped, short and clavate, antennomere 5 being the largest and subequal in length to 2
nd
. Paramedian tubercles/crests (
PM
) especially strongly developed, high, each tightly fused medially almost all along and only apically slightly divided, inclined anteriad on collum and rings 2–4, subvertical until ring 16, thereafter declined increasingly caudad (
Figs 3 & 4
).
PM
mostly thickened and vaguely bilobate apically, only last few
PM
trilobate (
Fig. 4
). Paraterga very low, oblique and strongly declined, vaguely bi- or trilobate at lateral margin (
Figs 3–6
). Pore formula normal (5, 7, 9, 10, 12, 13, 15–19), ozopores borne on distinct porosteles on rings 5, 7, 9, 10, 12, 13 and 15, but opening flush on dorsal surface at base of caudal lobulation on rings 16–19 (
Figs 3–6
). Surface below
PM
microgranulate, with neither
DL
nor
i
, nor
Am
, nor
Cm
discernible beneath an earth crust.
PM
19 subhorizontal, fused medially and forming a deep caudal notch, tip of epiproct being slightly visible from above.
Legs robust, densely setose, each prefemur with a particularly long distoventral seta; claw small and simple (
Figs 5 & 6
). Gonopods (
Figs 7 & 8
) relatively simple,
in situ
held almost parallel to each other, with only tips of telopodites (= solenomeres), both slightly curved ventrad and poorly bifid, crossing medially; each gonopod consisting of a large, globose, densely microsetose and micropapillate coxite and a unipartite, rather long, ribbon-shaped, distally attenuating telopodite/solenomere curved caudad, strongly sunken inside a deep gonocoel and terminating the seminal groove on top.
Distribution.
Pundaluoya,
Sri Lanka
.