Eutrichodesmus planatus, Liu, Weixin & Tian, Mingyi, 2013

Liu, Weixin & Tian, Mingyi, 2013, Four new cavernicolous species of the millipede genus Eutrichodesmus Silvestri, 1910 from southern China (Diplopoda: Polydesmida: Haplodesmidae), Zootaxa 3734 (2), pp. 281-291 : 289-290

Eutrichodesmus planatus sp. n.

Figs 9–11

Material: Holotype male (SCAU), China, Guangxi Zhuang Autonomous Region, Hechi City, Liujia Town, Cave Zhenzhuyan, 22.11.2011, leg. Tian Mingyi, Liu Weixin, Zheng Yuan & Sun Feifei (CHIgx11-LWX07). Name: To emphasize the metaterga with several transverse rows of flattened tubercles.

Diagnosis: Differs from congeners by the metaterga behind the collum usually supporting three or four transverse mixostictic rows of tubercles, but the tubercles are distinctly flattened from segment 10 on towards the telson, whereas the gonopod telopodite has a conspicuous, denticulate, lateral, distofemoral process (dp) near midway and a biramous acropodite.

Description: All characters as in E. digitatus sp. n., except as follows.

Holotype ca 10 mm long and 2.5 mm wide. Coloration uniformly pallid.

Conglobation pattern typical of “ Doratodesmidae ”, but volvation apparently imperfect because of paraterga being too broad and mostly only slightly declivous, leaving small lacunae laterally even when body is maximally enrolled.

Antennae rather long and slender ( Fig. 9 A). Collum with several irregular transverse rows of round tubercles ( Fig. 9 B). Metaterga 2-16 usually with three or four transverse mixostictic rows of tubercles, following metaterga with more than four transverse mixostictic rows of tubercles, first row being highest and best expressed in anterior part of body ( Figs 9 B, E), but tubercles distinctly flattened from segment 10 on towards telson ( Fig. 9 H). Paraterga slightly declivous, rather broad, paraterga 3-11 directed laterad, following ones subhorizontal, hardly extending below level of venter. Paraterga 2 strongly enlarged, with four lobulations anterolaterally; paraterga 3 and 4 slightly shorter than others, slightly differently lobulate; following paraterga laterally with three or four distinct lobulations, caudolaterally at base with a distinct lobulation.

Sterna between ♂ coxae 6, 7 and 9 much wider. Legs rather long and slender, hardly reaching tips of paraterga.

Gonopods ( Figs 10–11 ) rather complex. Coxae subquadrate, large, microtuberculate and sparsely setose ventrolaterally. Telopodite much longer than coxite, clearly expanded just distal to a conspicuous, digitiform, simple, lateral, nearly midway, distofemoral process (dp), a mesal tooth (t) near dp base and, still more distally, a clearly biramus acropodite microdenticulate/fringed on both sides; seminal groove terminating in distal third on a clear-cut hairy pad.

Remarks: This is another typical “doratodesmid”, possibly a troglobite.

Figures

FIGURE 9. Eutrichodesmus planatus sp. n., male holotype. A-C. anterior body part, ventral, dorsal and lateral views, respectively. D-F. midbody segments, ventral, dorsal and lateral views, respectively. G-I. posterior body part, ventral, dorsal and lateral views, respectively. Photographed not to scale.

FIGURE 10. Eutrichodesmus planatus sp. n., male holotype. A-B. left gonopod, mesal and lateral view, respectively. Photographed not to scale.

FIGURE 11. Eutrichodesmus planatus sp. n., male holotype. A-B. left gonopod, mesal and lateral view, respectively. Scale bar: 0.2 mm.