Eutrichodesmus communicans 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 : 17-23

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

urn:lsid:zoobank.org:act:8293BC13-BF5A-4E2F-BCEE-0711CFC4C86E

Figs 9-13 .

Type material. Vanuatu, Espirito Santo, Malo Island, Avorani , forest litter, Berlese extraction, 15.IX.2006, leg. L. Deharveng & A. Bedos ( SK06-15/06 ), holotype ♂ ( MNHN JC 311 ), paratypes: 1 ♂, 4 ♀♀ ( MNHN JC 311 ), 1 ♂, 1 ♀ ( ZMUM), 1 ♀ ( NMNHS), 1 ♀ ( MCSNV), 1 ♀ ( ZMUC) ; same place, date and collectors ( SK06- 15/13 ), 1 ♂, 1 ♀, 1 juv. ( MNHN JC 311 ) ; Espirito Santo, Fapon doline 3, 5.IX.2006, leg. L. Deharveng & A. Bedos ( SK06-15/18 ), 5 ♀♀, 4 juv. ( MNHN JC 311 ), 1 ♂ ( SEM) ; Espirito Santo, very humid forest at Boutmas Pass , 27.IX.2006, leg. L. Deharveng & A. Bedos ( SK06-27/12 ), 1 ♂ ( MNHN JC 311 ) ; Espirito Santo, Boutmas, forest above Jourdain River , Berlese extraction of litter, 27.IX.2006, leg. L. Deharveng & A. Bedos ( SK06-27/09 ), 1 ♂ ( MNHN JC 311 ) ; Espirito Santo, Boutmas, Fapon doline 2, 5.IX.2006, leg. L. Deharveng & A. Bedos ( SK06-05/12 ), 2 ♀♀ ( MNHN JC 311 ) ; Espirito Santo, Funatus, Katae Cave , Berlese extraction of guano, 18.09.2006, leg. J. Lips ( SK06-18/07 , Katae 4gu), 1 ♂, 2 juv. ( ZMUC) .

Name. To emphasize a superficial transition from a still non-volvatory “haplodesmid” condition to the typical, fully volvatory “doratodesmid” one.

Diagnosis. Differs from congeners by the tergal trichome being composed of only very long, bisegmented, tactile setae, coupled with the gonopod telopodite having a peculiar, dentate-microtuberculate, lateral process at midway and a lobiform, slightly coiled distal part.

Description. Length of adults of both sexes ca 3.5-4.2 mm, width 0.6-0.75 mm, body broadest at segment 3 or 4; ♂♂ usually a little smaller than ♀♀. Holotype ca 3.8 mm long and 0.65 mm wide. Coloration uniformly pallid, ranging from white to light yellow or pink.

Adults with 19 segments, body subcylindrical ( Figs 9 ; 10A ), pattern of conglobation typical of “ Doratodesmidae ”, but volvation itself barely complete, poorly concealing at least legs of several caudal segments. Head ( Figs 10E, F ; 11A, B) slightly transverse, rather densely pilose, microgranular; isthmus between antennal sockets very narrow. Antennae ( Figs 11C, D ) very short and stout; antennomere 6 longer than 5, dorsoapically with an evident pit containing minute bacilliform sensilla; antennomere 8 with usual four sensory cones apically. Collum rather large, even and convex, not covering the head from above, very densely and irregularly setose, setae bisegmented, tactile ( Fig. 10F ). Prozona very finely alveolate, collum and metaterga covered with a rather even cerotegumental crust held by microvilli, this crust, like on collum, being perforated only by dense, irregularly arranged, tactile, bisegmented setae; stricture between pro- and metazona broad and shallow, even more finely alveolate than prozona; limbus entire, not

hidden by sparse microvilli ( Figs 11F ; 12 A-C). Paraterga subvertical and rather narrow, weakly set off by 1-2 shallow depressions or sulci, slightly bisinuate caudally at base ( Figs 10E ; 11E); paraterga 2 strongly enlarged, schism and hyposchism very small; paraterga

3 and 4 shorter than others ( Figs 9 ; 10A, E ), following paraterga broadly rounded, overlap typical. Pore formula normal, ozopores located near ventral margin, progressively closer to caudal corner of paraterga. Pleurotergal ridges very small, microgranular like entire ventral surface ( Fig. 11E ). Epiproct short, slightly uneven, directed ventrocaudad, below tip with the usual four cones; para- and hypoproct as in Figs 10C, D .

Sterna usually with a minute middle knob separating bases of nearly contiguous coxae ( Fig. 12D ), only sterna between coxae 6, 7 and 9 much wider ( Fig. 12E ). Gonopod aperture transverse-oval, relatively small, far from reaching lateral sides of segment 7, as in Fig. 12E . Legs relatively short; coxae and prefemora microgranular; tarsal segment longest; claw usual, simple, very slightly curved ventrad; some setae very sparsely microdenticulate ( Fig. 12D ). Coxae 1 of ♂ with a distinct distomedial spine, coxae 2 of ♂ perforated by vas deferens ( Fig. 11B ).

Gonopods ( Figs 12E, F ; 13 ) rather complex. Coxae subquadrate, very large, scaly, with only a few setae ventrolaterally.Telopodite only slightly longer than coxite, its basal part setose and slender, with a conspicuous, densely dentate-tuberculate, distofemoral outgrowth (dp) at about midway, more distally with an expanded, somewhat folded, coiled, broadly trifid lobe, carrying a very short solenomere branchlet laterally.

Remarks. This remarkable species partly bridges the former Haplodesmidae and Doratodesmidae in showing the tergal trichome of peculiar, bisegmented setae so characteristic of Cylindrodesmus (in which, however, it is mixed with usual setation), also shared with several true “doratodesmids”, on the one hand, and the body and gonopod structure of a rather typical “doratodesmid”, on the other.

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

Figure 10. Eutrichodesmus communicans sp. n., ♂ paratype from Fapon doline 3; A, habitus, lateral view; B, midbody segments, dorsal view; C, posterior part of body, dorsal view; D, same, ventral view; E, anterior part of body, ventrolateral view; F, same, front view. − Scale bars: A, 0.2 mm, B-F, 0.1 mm.

Figure 11. Eutrichodesmus communicans sp. n., ♂ paratype from Fapon doline 3; A, anterior part of body, ventral view; B, same, ventrocaudal view; C, antenna; D, apex of antenna; E, cross-section of a midbody segment, caudal view; F, texture of prozonite and limbus. − Scale bars: A, B, E, 0.1 mm, C, 0.05 mm, D, 0.01 mm & F, 0.02 mm.

Figure 12. Eutrichodesmus communicans sp. n., ♂ paratype from Fapon doline 3; A, metatergal cerotegument and bisegmented setae; B, same with microvilli, lateral view; C, same with base of a bisegmented seta; D, legs, ventral view; E, gonopods, ventral view; F, left gonopod, dorsolateral view. − Scale bars: A, B, 0.01 mm, C, 0.005 mm, D, F, 0.05 mm.

Figure 13. Eutrichodesmus communicans sp. n., ♂ paratype from Boutmas; A-D, left (A, B) and right (C, D) gonopods, lateral, mesal, mesal and lateral views, respectively (dp = distofemoral outgrowth). − Scale bar: 0.2 mm.