Eutrichodesmus similis Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009

Golovatch, Sergei, Geoffroy, Jean-Jacques, Mauriès, Jean-Paul & VandenSpiegel, Didier, 2009, Review of the millipede family Haplodesmidae Cook, 1895, with descriptions of some new or poorly-known species (Diplopoda, Polydesmida), ZooKeys 7 (7), pp. 1-53 : 26-29

Eutrichodesmus similis Golovatch, Geoffroy, Mauriès & VandenSpiegel , sp. n.

urn:lsid:zoobank.org:act:9CE9BBFF-66DF-42BC-B4E8-C44E2C71F972

Figs 18-21 .

Type material. China, Guangxi Prov., Mulun Nature Reserve, Gui Dong 2 Cave , 18.V. 2007, leg. F. Bréhier ( CHI-GX07-18/20 ), holotype ♂ ( IZAS), paratypes: 2 ♂♂, 2 ♀♀, 2 juv. ( MNHN JC 313 ), 1 ♂, 1 ♀ ( ZMUM), 1 ♂ ( ZMUC), 1 ♂ ( SEM) ; same locality, Shen Long Dong Cave , 22.V. 2007, leg. L. Deharveng & A. Bedos ( CHI-GX07-22/01 ); 1 ♂, 3 ♀♀, 4 juv. ( SCAU) .

Name. To emphasize the obvious similarities with the preceding species.

Diagnosis. See diagnosis of the previous species.

Description. Length of adults of both sexes ca 11-13 mm, width 3.0- 3.3 mm; ♂♂ usually a little smaller than ♀♀. Holotype ca 12 mm long and 3.0 mm wide. Coloration uniformly pallid or light yellowish, only seldom marbled light-brownish.

All characters virtually as in E. latus sp. n. ( Figs 18 A-C, E, F; 19B-F; 20A, B), but collum with a row of very conspicuous teeth at front margin ( Figs 18D ; 19A ).

Gonopods ( Figs 20C, D ; 21 ) slightly more complex than in E. latus sp. n. Telopodite distally somewhat expanded and folded, with a hairpad subapically.

Remarks. Together with E. latus sp. n., this remarkable species partly bridges the gap between “doratodesmoid” Haplodesmidae and the large tropical family Cryptodesmidae Karsch, 1879 in showing the very broad and, at most, only slightly declivous paraterga so characteristic of cryptodesmids, including those occurring in East and Southeast Asia ( Hoffman 1980; Simonsen 1990). However, the metaterga in Cryptodesmidae are often densely setose, the collum is always enlarged, flabellate and covering the head from above to an even greater extent than it does in Pyrgodesmidae ,

whereas the paraterga are often deeply incised caudolaterally or have clear radii, again much as in some Pyrgodesmidae . Therefore, it seems safe for the present to consider the Cryptodesmidae as a distinct family in the superfamily Polydesmoidea ( Hoffman 1980, 1982 b; Simonsen 1990).

What is more remarkable, however, is that the above two new Chinese species have the body so strongly flattened, and the paraterga apparently too broad to allow a tight volvation. This condition represents the opposite to that observed for E. basalis sp. n., in which the paraterga are obviously too short to permit complete volvation. In other words, within Eutrichodesmus we find species representing virtually the entire spectrum

of “doratodesmid” evolution of conglobation, including a few exceptional cases of imperfect volvation.

Concerning the two new Chinese species that are not capable of complete conglobation, the situation somewhat parallels that observed in Proeilodesmus mecistonyx Hoffman, 1990 ( Sphaeriodesmidae Humbert & DeSaussure, 1869 , Sphaeriodesmoidea), a cavernicole from Mexico that is apparently incapable of volvation ( Hoffman 1990). In contrast to “doratodesmids”, however, most of the characters of this millipede seem plesiomorphic and suggest a link between a presumed flat-bodied chelodesmidean (= leptodesmidean) ancestor and the remaining, convex, truly volvatory members of this rather large, Neotropical family ( Hoffman 1990; Golovatch 2003).

Figures

Figure 1. Eutrichodesmus basalis sp. n., ♀ paratype; A, habitus, lateral view; B, anterior part of body, lateral view; C, midbody segments, lateral view; D, posterior part of body, lateral view; E, midbody segments, dorsal view; F, posterior part of body, dorsal view. − Scale bars: A, 0.5 mm, B, C, D & F, 0.1 mm & E, 0.2 mm.

Figure 2. Eutrichodesmus basalis sp. n., ♀ paratype; A, anterior part of body, frontodorsal view; B, head, front view; C, antenna; D, cross-section of a midbody segment, caudal view; E, posterior part of body, ventral view; F, legs, ventral view. − Scale bars: A, B, D, E, 0.1 mm & C, F, 0.05 mm.

Figure 3. Eutrichodesmus basalis sp. n., ♀ paratype; A, enlarged paraterga with ozopores, lateral view; B, bisegmented seta; C, tegument texture; D, limbus and adjacent parts; E, claw. − Scale bars: A, 0.05 mm, B, D, E, 0.01 mm, C, 0.02 mm.

Figure 4. Eutrichodesmus basalis sp. n., ♂ paratype; A, leg 9, caudal view; B & C, left gonopod, mesal and lateral views, respectively (dp = distofemoral process). − Scale bar: A, 0.2 mm, B, C, 0.1 mm.

Figure 5. Eutrichodesmus armatocaudatus sp. n., ♂ paratype from cave 4; A, habitus, lateral view; B, midbody segments, lateral view; C, posterior part of body, lateral view; D, midbody segments, ventral view; E, posterior part of body, ventral view; F, telson, ventral view. − Scale bars: A, 1.0 mm, B, C, E, 0.2 mm, D, 0.5 mm & F, 0.1 mm.

Figure 6. Eutrichodesmus armatocaudatus sp. n., ♂ paratype from cave 4; A, anterior part of body, frontoventral view; B, cross-section of a midbody segment, caudal view; C, enlarged paraterga with ozopores, lateral view; D, paratergum with porostele, caudal view; E, porostele; F, texture of prozonite and limbus; G, cerotegument with a bisegmented seta. − Scale bars: A, B, 0.2 mm, C, D, 0.1 mm, E, G, 0.01 mm & F, 0.05 mm.

Figure 7. Eutrichodesmus armatocaudatus sp. n., ♂ paratype from cave 4; A, body segments 6 and 7, ventral view; B, gonopods, ventral view; C, same, ventral view; D, gonopod apices. − Scale bars: A, 0.5 mm, B, 0.2 mm, C, 0.05 mm & D, 0.02 mm.

Figure 8. Eutrichodesmus armatocaudatus sp. n., ♂ paratype from cave 4; A & B, right gonopod, mesal and lateral views, respectively (micropilosity not shown; dp = distofemoral process). − Scale bar: 0.2 mm.

Figure 9. Eutrichodesmus communicans sp. n., ♂ paratype from Malo Island, habitus.

Figure 18. Eutrichodesmus similis sp. n., ♂ paratype from Gui Dong 2 Cave; A, anterior part of body, lateral view; B, midbody segments, lateral view; C, posterior part of body, lateral view; D, anterior part of body, dorsal view; E, midbody segments, dorsal view; F, posterior part of body, dorsal view. − Scale bars: A-E, 0.5 mm & F, 0.2 mm.

Figure 19. Eutrichodesmus similis sp. n., ♂ paratype from Gui Dong 2 Cave; A, anterior part of body, ventral view; B, segments 5-9, ventral view; C, posterior part of body, ventral view; D, cross-section of segment 4, caudal view; E, texture of prozonite, limbus and bisegmented seta; F, metatergal cerotegument with a bisegmented seta. − Scale bars: A, D, 0.5 mm, B, 1.0 mm, C, 0.02, E, 0.01 mm & F, 0.005 mm.

Figure 20. Eutrichodesmus similis sp. n., ♂ paratype from Gui Dong 2 Cave; A, paratergum with ozopore, lateral view; B, leg; C, gonopods, ventral view; D, gonopod apex, ventral view. − Scale bars: A-C, 0.1 mm & D, 0.05 mm.

Figure 21. Eutrichodesmus similis sp. n., ♂ paratype from Gui Dong 2 Cave; A, left gonopod, mesal view; B & C, distal half of right gonopod, mesal and lateral views, respectively (dp = distofemoral process). − Scale bar: 0.2 mm.