Enghoffosoma fedorenkoi ( Golovatch, 2016 ) Golovatch, 2016

Nguyen, Anh D. & Golovatch, Sergei I., 2016, The millipede genus Enghoffosoma Golovatch, 1993 recorded in Vietnam for the first time, with descriptions of three new species (Diplopoda, Polydesmida, Paradoxosomatidae), Zootaxa 4139 (2), pp. 151-166 : 154-156

Enghoffosoma fedorenkoi ( Golovatch, 2016) comb. nov.

( Figs 3–5 )

Sundanina fedorenkoi Golovatch, 2016: 149 , figs 79–90.

Material examined. 1 male (IEBR-Myr 249), Vietnam, Dak Lak Prov., Chu Yan Sin National Park, coniferous and broadleaved forests, 1000–1500 m a.s.l., 28 March–12 April 2012, leg. Le X. Son; 1 male (damaged), 1 female (IEBR-Myr 119), Vietnam, Lam Dong Prov., Bi Doup-Nui Ba National Park, Pinus forest, 1400 m a.s.l., pitfall trapping, 7 May 2009, leg. Anh Duc Nguyen.

Descriptive notes. There are a number of apparently intraspecific variations observed in the new samples as compared to the original description ( Golovatch 2016). In comparison with holotype, a sympatric material from Chu Yan Sin National Park is considerably larger in size, up to 35.6 mm long (vs ca 22–27 mm); width of pro- and metazonae 3.2 mm and 3.8 mm, respectively (vs 2.5–3.3 and 3.0–4.0 mm, respectively).

The new material shows a subtriangular hypoproct with two separated distolateral setae borne on small knobs ( Fig. 3 I); male sternum 5 with a densely setose, bifid, trapeziform lobe between coxae 4 ( Fig. 3 C); legs stout and strong, especially three last pairs of legs, 1.2–1.3 times as long as midbody height; and ventral brushes on tarsi being present until segment 12, thereafter thinning out. In contrast, the holotype has a semi-circular hypoproct with two separated distolateral setae which are not borne on knobs; male sternum 5 shows a pair of small, densely setose, basally subcontiguous, rounded lobes between coxae 4; the legs are longer (in the male about 1.4–1.5 times as long as midbody height); and ventral brushes are present on all tarsi ( Golovatch 2016).

Except for the above differences, the new material totally agrees with the holotype in the gonopod conformation. The gonopod femorite is slender, slightly curved, with neither processes nor other modifications. The postfemoral region is separated from the femorite by a distinct cingulum and consists only of a long parabasal process and a long, thick, gradually attenuated solenomere. The distal part of the solenomere is twisted.

Remarks. Golovatch (2016) described this species as Sundanina fedorenkoi , based on 2 males coming from the Chu Yan Sin National Park. So some of our material represents a strict topotype. Golovatch also emphasized his strong hesitation in placing that species in the genus Sundanina Attems, 1914 , a member of the tribe Sundaninini. Indeed, the gonopods in the latter genus and tribe always show a (disto)femoral outgrowth or process and a slender flagelliform solenomere, whereas in S. fedorenkoi the former is absent while the latter is conspicuously thick. As such conditions fully fit in the diagnosis of Enghoffosoma as given by Likhitrakarn et al. (2014) and above, we do not hesitate to formally transfer S. fedorenkoi to Enghoffosoma . This results in the following new combination: Enghoffosoma fedorenkoi ( Golovatch, 2016) , comb. nov. ex Sundanina .

The species is fairly similar to E. triangulare sp. nov. in the paraterga being well-developed, the gonopod femorite slender and devoid of processes, the postfemoral region consisting only of a solenomere and a process e, and the solenomere showing a distal tooth terminating the seminal groove. Process e is triangular in E. triangulare sp. nov., but oar-shaped in E. fedorenkoi .

Figures

FIGURE 3. Enghoffosoma fedorenkoi (Golovatch, 2016), comb. nov., male from Chu Yan Sin National Park, Vietnam. Anterior segments, dorsal view (A), lateral view (B); midbody segments, dorsal view (D), lateral view (E), ventral view (F); posterior segments, dorsal view (G), lateral view (H), ventral view (I); sternum between coxae 4, ventral view (C). Scale = 1 mm.

FIGURE 4. Enghoffosoma fedorenkoi (Golovatch, 2016), comb. nov., male from Chu Yan Sin National Park, Vietnam. Right gonopod, lateral view (A); mesal view (B). Scale = 1 mm.

FIGURE 5. Enghoffosoma fedorenkoi (Golovatch, 2016), comb. nov., male from Chu Yan Sin National Park; Vietnam. Left gonopod, lateroventral view (A), mesoventral view (B).