Plusioglyphiulus, Silvestri, 1923

Golovatch, Sergei I., Geoffroy, Jean-Jacques, Mauriès, Jean-Paul & Vandenspiegel, Didier, 2011, The millipede genus Plusioglyphiulus Silvestri, 1923 in Thailand (Diplopoda, Spirostreptida, Cambalopsidae) 2940, Zootaxa 2940 (1), pp. 1-63 : 60-61

Key to species of Plusioglyphiulus :

1. Crests on collum not differentiated, arranged in two transverse rows ( Figs 5A, D), just like in typical Glyphiulus species. Gonopods also much like in typical Glyphiulus species ( Figs 7F, G), but each posterior gonopod coxite with a distinct apical ampulla devoid of a nearby flagellum ( Fig. 7G)..................................................... P. antiquior

– Crests on collum markedly differentiated, usually broken and arranged in three transverse rows ( Figs 1A, D, 8A, D). Anterior gonopods usually not shield-shaped like in typical Glyphiulus species , but more complex and typically divided into a pair of anterior and posterior coxosternal processes ( Figs 11G, 15C, 18C, D). Each posterior gonopod coxite with a distinct apical ampulla either supplied with a nearby flagellum or not; when supplied, then flagellum nearly always simple ( Figs 11H, 18E, F), very rarely plumose or serrate ( Fig. 15D)................................................................ 2

2. At least some crests on collum complete ( Figs 8A, D, 28A, D, 39A, D, 51A, D).................................... 3

– No complete crests on collum, all interrupted ( Figs 1A, D, 12A, D, 16A, D)....................................... 9

3. Collum with 3(4)+3(4) complete crests..................................................................... 4

– Collum with 5(6)+5(6) or 1+1 complete crests............................................................... 6

4. Complete crests on collum: 2, 3 and 4, paramedians incomplete. Sabah, Malaysia........................ P.macfarlanei

– Complete crests on collum always including paramedians...................................................... 5

5. Collum with 3+3 complete crests ( Figs 28A, D). Gonopods as in Figs 30B–D, 31C–E. North-central Thailand....... P.tham

– Collum with 4+4 complete crests ( Figs 51A, D). Gonopods as in Figs 52F, G. Southern Vietnam.............. P. ampullifer

6. Only paramedians on collum complete. Carinotaxy formula of midbody segments, 3/3+I/i+3/3/3+m/m/m. Thailand........ 7

– Collum with 5(6)+5(6) complete crests. Carinotaxy formula of midbody metaterga different. Borneo................... 8

7. Gonopods as in Figs 41G, H.................................................................... P . puttakun

– Gonopods as in Figs 11G, H.................................................................... P . sutchariti

8. Carinotaxy formula of midbody segments, 3/3+I/i+2/2+m/m. Cave in Sarawak, Malaysia................ P. cavernicolus

– Carinotaxy formula of midbody segments, 4/4+I/i+3/3/3+m/m. Cave in Kalimantan, Indonesia................ P. bedosae

9. Carinotaxy pattern of collum isostichic (i.e. devoid of intercalary tubercles or crests). Laos.................... P.steineri

– Carinotaxy pattern of collum mixostichic.................................................................. 10

10. Carinotaxy formula of midbody metaterga 3/3+I/i+3/3+m/m. Anterior gonopods with a prominent, spiniform, median, sternal process. Caves in Malaya.................................................................... P. grandicollis

– Carinotaxy formulae of midbody metaterga different. Anterior gonopods without sternal process...................... 11

11. Carinotaxy formula of midbody metaterga, 2/2+I/i+1/1+m/m. Male leg 1 with a relatively short central hook ( Fig. 4C). Male leg 2 moderately enlarged ( Fig. 4D). Anterior gonopods shield-shaped ( Figs 3D, 4G), like in Glyphiulus species. Posterior gonopods much like in P. antiquior , but supplied with evident, bare flagella on top ( Figs 3B, C, 4H)............. P. panhai

– Carinotaxy formulae of midbody metaterga different. Male leg 1 with a strong, long, central hook ( Fig. 11C). Male leg 2 moderately enlarged ( Fig. 11D). Anterior gonopods much more elaborate, with two pairs of prominent processes ( Figs 11G, 15C, 18C). Posterior gonopods different, telopodites rudimentary to missing......................................... 12

12. Second transverse row of tubercles on midbody segments intercalary, apparently developed only towards onset of sexual maturity, formula 3/3+I/i+3/4/3+m//m. Epiproct short. Legs more or less as long as body diameter. Borneo................. 13

– Dorsal tubercles or crests arranged in clear-cut longitudinal rows, pattern isostichic ( Figs 12B, E, 16B, E, 20B, E). Epiproct longer ( Figs 12C, F, 13D, E, 16C, F, 20C, F). Legs usually closer to being half as long as body diameter ( Figs 13F, 17E, 21F). ................................................................................................... 15

13. Body length 43–50 mm, width 2.0– 2.1 mm; segments 64–70p+2–1a+ T. Collum with a distinct transverse impression near anterior 1/3. Carinotaxy formula of midbody segments 2/2+I/i+3/4/3+m//m. Paraprocts flattened. Kalimantan .... P. pallidior

– Body length up to about 30 mm, width 1.0– 1.6 mm; segments up to 53p+1a+T. Collum not particularly impressed near anterior 1/3. Carinotaxy formula of midbody segments 3/3+I/i+3/4(5)/3+m//m. Paraprocts regularly convex................... 14

14. Brown spots present dorsad of ocellaria. Epiproct very short, roundly subtrapeziform. Anterior gonopods without cxp2. Lateral arms of posterior gonopods rudimentary. Sarawak.................................................... P. hoffmani

– Brown spots absent dorsad of ocellaria. Epiproct a little longer, regularly rounded. Anterior gonopods swollen, stout, with both cxp1 and cxp2 present. Lateral arms of posterior gonopods long and spiniform. Kalimantan ..................... P. similis

15. General coloration very dark brown to blackish (fading to reddish after long conservation in alcohol). Paraprocts with a distinct, median, ridge-like elevation. Cambodia........................................................ P. dubius

– General coloration lighter, usually yellow-brown to brown. Paraprocts flat medially................................ 16

16. Paraprocts strongly flattened. Each posterior gonopod with a long lateral spine.......................... P. deharvengi

– Paraprocts regularly convex ( Figs 12C, 16C, 20C). Posterior gonopods without long spine laterally.................... 17

17. Carinotaxy of midbody metaterga, 3/3+I/i+3/3/3+m/m/m, changing 4/4+I/i+3/3/3+m/m toward caudal third of body...... 18

– Basic carinotaxy of midbody metaterga, 3/3+I/i+3/3/3+m/m/m, remaining unchanged toward telson.................. 23

18. Anterior gonopods as in Figs 14D, E, 15C; posterior gonopods with plumose flagella on top ( Fig. 15D).......................................................................................................... P. likhitrakarni

– Anterior gonopods different; flagella on posterior gonopods either simple or absent................................ 19

19. Anterior gonopods with cxp1 considerably longer than cxp2 ( Figs 22C–E, 23G); flagella on to posterior gonopods very short, telopodites missing, but coxite with a conspicuous frontomedial arm ( Fig. 23H)............................. P. erawan

– Anterior gonopods with cxp1 usually shorter than to about as long as cxp2; posterior gonopods different, a frontomedian arm less conspicuous or missing............................................................................ 20

20. Anterior gonopods as in Figs 26D, E, 27C; posterior gonopods shield-like, front arms short ( Figs 26F, 27D).......... P.wat

– Both gonopod pairs different............................................................................ 21

21. Anterior gonopods as in Figs 18C, D, 19F; posterior gonopods with very long flagella on top ( Figs 18E, F, 19G).................................................................................................... P.pimvichaiae

– Both gonopod pairs different............................................................................ 22

22. Anterior gonopods with rounded tips of cxp1 ( Figs 34A–D, 35F); posterior gonopods virtually devoid of flagella ( Figs 34E, F, 35G)........................................................................................... P. phra

– Anterior gonopods with acuminate cxp1 ( Fig. 50F); posterior gonopods more elaborate, flagella present ( Fig. 50G)...................................................................................................... P. bessoni

23. Brown spots present dorsad of ocellaria. Anterior gonopods with very short and lobe-like cxp1. Posterior gonopods without arms. Cambodia................................................................................ P. boutini

– Brown spots absent dorsad of ocellaria. Anterior gonopods with both cxp1 and cxp2 equally well developed. Posterior gonopods with or without arms............................................................................... 24

24. Anterior gonopods as in Figs 47G, H; posterior gonopods more elaborate, with clear telopodite remains ( Fig. 47I)..................................................................................................... P. samakkee

– Both gonopod pairs different............................................................................ 25

25. Anterior gonopods with both cxp1 and cxp2 bifid; posterior gonopods with rudimentary arms, devoid of flagella. Laos.................................................................................................. P. foveatus

– Anterior gonopods with cxp1 uncinate while cxp2 tip either digitiform or expanded; posterior gonopods without arms, but with flagella. Thailand..................................................................................... 26

26. Anterior gonopods with digitiform cxp2 ( Fig. 38E); posterior gonopods as in Figs 38F, G...................... P . jaydee

– Anterior gonopods with subtriangular tips of cxp2 ( Fig. 44G); posterior gonopods as in Fig. 44H................ P .saksit