Zoosphaerium libidinosum (de Saussure & Zehntner, 1897)

Wesener, Thomas & Sagorny, Christina, 2021, Seven new giant pill-millipede species and numerous new records of the genus Zoosphaerium from Madagascar (Diplopoda, Sphaerotheriida, Arthrosphaeridae), European Journal of Taxonomy 758 (1), pp. 1-48 : 7-9

Zoosphaerium libidinosum species-group

Remarks

Species can be identified as members of the Z. libidinosum species-group based on morphological characters of the posterior telopods, in which the third telopoditomere carries more than 15 large crenulated teeth as well as two large membranous lobes ( Wesener & Wägele 2008). The species-group now contains 16 described species distributed in all types of forests all over Madagascar, including the arid spiny bush (Wesener 2009).

Key to species of the Zoosphaerium libidinosum species-group

1. Anal shield without locking carinae (in small, immature individuals sometimes traces of carinae are visible).........................................................................................................................................2

– Anal shield with two obvious locking carinae..............................................................................7

2. Operculum of vulva at least weakly notched apically. Fifth antennomere with field of sensilla basiconica apically............................................................................................................................3

– Operculum of vulva well-rounded apically. No sensilla basiconica present on fifth antennomere...............................................................................................................................................4

3. Tergites dark green, in alcohol almost blackish, posterior margin light brown to yellow. Tarsus of walking legs broad, only 3.0 times as long as wide. Third podomere of anterior telopods with four large, sclerotized teeth. Endotergal marginal bristles strongly extending beyond tergite ....... .................................................................................................................. Z. haackeri Wesener, 2009

– Tergites almost white, with light, shiny-green field dorso-laterally on each side. Tarsus of walking legs of usual size, 3.8 times as long as wide. Third podomere of anterior telopods with single large, sclerotized tooth. Endotergal marginal bristles slightly extending beyond tergite .......................... ...................................................................................................................... Z. album Wesener, 2009

4. Anterior telopod second podomere process slightly extending beyond third podomere. Third podomere laterally with plateau and mesally with a sharp, prominent process. Tergites light green with distinct, light brown posterior margin. Male harp with two weakly-developed stridulation ribs ............................................................................................................ Z. discolor Wesener, 2009

– Anterior telopod second podomere process shorter than third podomere. Third podomere of anterior telopods only laterally with plateau....................................................................................5

5. Tergites dark, almost blackish green, posteriorly with distinct and wide light brown margin. Anal shield covered with numerous short hairs. Endotergum with a single row of marginal bristles, slightly extending beyond tergite .............................................................. Z. mitoho Wesener, 2009

– Tergites with dark green, light green pattern, posteriorly with distinct, thin light brown margin. Anal shield glabrous. Endotergum with two or more rows of marginal bristles, clearly extending beyond apical margin.......................................................................................................................6

6. Endotergum with ≥ 3 rows of marginal bristles, strongly extending beyond tergite. Third podomere of anterior telopods laterally with a triangular projection. Tarsi of walking legs>3.7 times as long as wide. Male harp with two strongly developed stridulation ribs ............................. ................................................................................ Z. libidinosum (de Saussure & Zehntner, 1897)

– Endotergum with two rows of marginal bristles, strongly extending beyond tergite. Third podomere of anterior telopods laterally without triangular projection. Tarsi of walking legs 3.5 times as long as wide. Male harp with two weakly developed stridulation ribs ........................... Z. silens sp. nov.

7. Second and third podomeres of posterior telopods covered with numerous minute hairs. Antennae with four apical cones; tergites glossy, glabrous...............................................................................8

– Second and third podomeres of posterior telopods glabrous or covered with long setae...........10

8. Tergites black. Anterior telopod with one stridulation rib .................................... Z. nigrum sp. nov.

– Tergites jade-like green. Anterior telopod at least apically with 2 stridulation ribs........................9

9. Tergites glossy, completely jade-like green. Male harp with two basally fused stridulation ribs. Third podomere of anterior telopods mesally with sharp, prominent process. Endotergum with one row of rounded cuticular impressions. Fixed finger of posterior telopod basally without membranous lobe ..................................................... Z. anomalum (de Saussure & Zehntner, 1902)

– Tergites glossy, jade-like green, with shiny dark green pattern. Male harp with two fully separate stridulation ribs. Third podomere of anterior telopods without process. Endotergum without cuticular impressions. Fixed finger of posterior telopod with basal membranous lobe ...................... ............................................................................................................... Z. pulchellum Wesener, 2009

10. Posterior end of anal shield in both sexes excavated..................................................................11

– Posterior end of anal shield well-rounded....................................................................................14

11. Tergites glossy, green. Male harp with two weakly-developed stridulation ribs. Third podomere of anterior telopods with a single large sclerotized tooth ............ Z. endemicum Wesener, 2009

– Tergites matte, brownish. Male harp with two well-developed stridulation ribs........................12

12. Locking carinae on anal shield of similar length. Third podomere of posterior telopods with ca 28 large sclerotized teeth. Antenna with more than 40 apical cones ............................................... ............................................................................................................. Z. xerophilum Wesener, 2009

– Posterior locking carina at least two times as long as anterior carina. Third podomere of posterior telopods with less than 25 large sclerotized teeth. Antenna with less than 30 apical cones ......................................................................................................................................................13

13. Posterior locking carina of anal shield more than three times as long as anterior carina ............ ........................................................................................... Z. arborealis Wesener & Sierwald, 2005

– Posterior locking carina ca twice as long as anterior one ..... Z. lambertoni ( Brolemann, 1922)

14. Anal shield glabrous, golden. Tergites with unique pitch-black/reddish-brown pattern. Third podomere of anterior telopods without large sclerotized teeth. First antennomere without sensilla basiconica. Sclerotized teeth present on antennomeres 1–4. Endotergal marginal bristles not extending beyond tergite margin ................................................................................. Z. aureum Wesener, 2009

– Anal shield covered with few, minute hairs of dirty brownish color. Tergites with light brown, blackish coloration pattern. Third podomere of anterior telopods laterally with at least a single large sclerotized tooth. First antennomere with sensilla basiconica. Sclerotized teeth present on antennomeres 1–5. Endotergal marginal bristles slightly extending beyond tergite margin.........15

15. Legs short, femur 1.45 times as long as wide, tarsus 3.2 times as long as wide. Third pair of legs without apical spine. Third podomere of posterior telopods with ca 18 large sclerotized teeth. Endotergum with two rows of marginal bristles. Posterior locking carina 4 times as long as anterior carina. Antenna with 25 or fewer apical cones ......... Z. priapus (de Saussure & Zehntner, 1897)

– Legs of usual size, femur 1.9 times as long as wide, tarsus 4.2 times as long as wide. Third pair of legs with apical spine. Third podomere of posterior telopods with ca 22 large sclerotized teeth. Endotergum with three rows of marginal bristles. Locking carinae of equal size. Antenna with 35–86 apical cones ........................................... Z. pseudopriapus Wesener, 2009