Hylomus songoku Nguyen & Nguyen & Nguyen & Phung 2019, sp. nov.
Creators: name: Nguyen, Anh D.
name: Nguyen, Manh-Ha
name: Nguyen, Thu-Anh T.
name: Phung, Hong-Luong T.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Diplopoda
Polydesmida
Paradoxosomatidae
Hylomus
Hylomus songoku

description: Hylomus songoku sp. nov.
(Figs. 1, 16−20) urn:lsid:zoobank.org:act: 030505EE-DF75-4832-ABF1- CC70AB989A03
Material examined: Holotype: 1 male (IEBR- Myr 164H) Phu Tho Province, Xuan Son National Park, Lap cave, 11 December 2010, coll. Phung T. H. Luong. Paratypes: 1 male, 3 females (IEBR-Myr 164P) same data as holotype.
Etymology: The name refers to “ songoku ”, a main character of the Japanese manga “Dragon balls” by Toriyama Akira (Japan).
Diagnosis: The species differs from its congeners in suberect gonopod; solenophore with rounded lobuliform lamina medialis, and well developed lamina lateralis with densely setose area; tip of solenophore tuberculiform.
Description: Body length ca. 17.9−25.2 mm (male), 23.9−26.8 mm (female); width of midbody pro- and metazonae 1.1−1.2 mm (male), 2.1−2.3 mm (female) and 1.3−1.4 mm (male), 2.4−2.5 mm (female), respectively. Holotype length 25.2 mm, width of midbody pro- and metazonae 1.2 mm and 1.4 mm, respectively.
Colouration (Figs. 16−18): body generally light yellow. Pleura yellowish brown; head yellowish and somewhat darker on the region between antenna sockets.
Head (Fig. 16A) slightly broader than collum. Clypeolabral region densely setose. Epicranial suture distinct, linear. Antennae (Fig. 16A) slender, thin and extremely long, reaching segment 7 or 8 if stretched posteriorly; antennomere 3> 4> 5> 2> 6> 7> 1 in length; antennomere 7 black.
Collum (Figs. 16 A−B) somewhat narrower than segment 2 in width; surface shining, densely microgranulated and wrinkled, with two rows of setiferous spines: one of 10−12 smaller spines close to anterior margin and, one of 4 + 4 larger spines near posterior margin; the posterior spines gradually smaller medially. Paraterga well developed, highly elevated, antler-shaped with three branches.
Width of body segment 4 <3 <2 = 5−16, thereafter gradually tapering towards telson. Prozonae shining and shagreened. Metazonae with dense microgranulation. Transverse sulcus starting on metatergum 5, but vague, incomplete, thin and line-shaped. Metaterga densely granulated with two rows of setiferous spines; the anterior spines variable, tiny whereas posterior spines longer and larger, 3 + 3 on metaterga 2−3, 4 + 4 on metaterga 4−5, 5(6) + 5(6) on subsequent metaterga (Figs. 16 C−D, 17A, C); metatergum 19 with numerous small setiferous spines, but not arranged in row. Pleurosternal carinae absent. Axial line present, thin and line-shaped. Waist between pro- and metazonae broad, neither striolate nor beaded.
Paraterga (Figs. 16, 17 A−C) well developed, antler-shaped, with 5−6 branches (one main branch, 2−3 anterior ones and 1−2 posterior ones), highly elevated from metatergal surface, sometimes with several very tiny setiferous spines around base. Ozopore on segments 5, 7, 9−10, 12−13, and 15−19, lying under the base of the second anterior branch.
Epiproct (Figs. 17D, 18 A−B) strongly modified with two large lateral setiferous tubercles. Tip normal with four spinnerets. Hypoproct (Fig. 18B) trapeziform with two well separated, distolateral setiferous knobs.
Sterna (Fig. 17 D) modestly setose; cross impression vague, without modifications except two separated, setiferous tubeliform processes between coxae 4 (Fig. 18C).
Legs slender and extremely long, about 3−3.5 times as long as midbody height. Prefemora not swollen. Femora without modifications except femora 6 & 7 with a big ventral tubercle at 2/3 its length (Fig. 18D). Tarsal brushes absent.
Gonopod (Figs. 19−20) simple. Coxite (co) about 1/3 as long as telopodite. Prefemorite (prf) about half as long as acropodite, densely setose, demarcated laterally from femorite by a transverse sulcus. Femorite (fe) longer than postfemoral region, slightly enlarged distally, and somewhat curved ventrad. Postfemoral region suberect, consisting of solenophore (sph) and solenomere (sl). The former simple with a rounded lobuform (rl) lamina medialis and well developed lamina lateralis with a densely setose region (ds). Solenomere flagelliform, partly sheathed by solenophore. Seminal groove running entirely mesally, directed distodorsad before entering the solenophore. Tip (tp) of solenophore tuberculiform.
Remarks: The species was found in the Lap cave, and it is the first troglobitic species of the genus Hylomus recorded in Vietnam.
description: Published as part of Nguyen, Anh D., Nguyen, Manh-Ha, Nguyen, Thu-Anh T. & Phung, Hong-Luong T., 2019, Review of Dragon Millipedes (Diplopoda, Polydesmida, Paradoxosomatidae) in the Fauna of Vietnam, with Descriptions of Three New Species, pp. 1-31 in Zoological Studies 58 (14) on pages 13-18, DOI: 10.6620/ZS.2019.58-14, http://zenodo.org/record/8065869