Orthomorphoides sapa, Nguyen & Nguyen & Eguchi, 2021

Nguyen, Anh D., Nguyen, Dai Dac & Eguchi, Katsuyuki, 2021, Mountainous millipedes in Vietnam. I. Two new species of the family Paradoxosomatidae from Mount Fansipan (Diplopoda, Polydesmida), ZooKeys 1032, pp. 1-15 : 1

publication ID	https://dx.doi.org/10.3897/zookeys.1032.64917
publication LSID	lsid:zoobank.org:pub:E45C61A8-6565-4AB5-B5FC-AD907A9B4738
persistent identifier	https://treatment.plazi.org/id/3BBAA752-06DC-47AD-894A-FAD9AD6E8283
taxon LSID	lsid:zoobank.org:act:3BBAA752-06DC-47AD-894A-FAD9AD6E8283
treatment provided by	ZooKeys by Pensoft
scientific name	Orthomorphoides sapa
status	sp. nov.

Treatment

Orthomorphoides sapa sp. nov. Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5

Material examined.

Holotype: male (IEBR-Myr 710H), Vietnam, Lao Cai Province, Hoang Lien National Park , natural forest, 22.32250°N, 103.77081°E, 2478 m a.s.l., 7 July 2018, coll. Nguyen Dac-Dai. GoogleMaps Paratype: 1 female (IEBR-Myr 710P), together with holotype.

Diagnosis.

The species is easily recognized by having a black sub-moniliform body, small and crest-shaped paraterga, a long and slender gonofemorite, a simple solenophore with neither modifications nor additional processes, a poorly developed lamina medialis, a well-developed lamina lateralis with a tongue-shaped process, and the gonopod tip with a broad apical lobule.

Description.

Holotype body length about 22.1 mm, width of pro- and metazona 1.6 mm and 2.1 mm, respectively.

Colouration (Figs 1 View Figure 1 - 2 View Figure 2 ): body black except whitish yellow legs and sterna; several podomeres light brown.

Head (Fig. 1A, B View Figure 1 ) somewhat larger than collum, clypeolabral region densely setose, vertex sparsely setose. Epicranial suture distinct; frons with 2+2 setae along epicranial suture. Antenna long, slender, reaching segment 3 if stretched laterally; antennomere 2>3=4=5=6>1>7; tip with four sensory cones.

Collum (Fig. 1B View Figure 1 ) semicircular; surface smooth, shining with two rows of setae: 4+4 anterior and 1+1 intermediate; transverse sulcus present, but short, indistinct. Paratergum present, crest-shaped.

Body sub-moniliform (Figs 1C, D View Figure 1 , 2C View Figure 2 ). Surface smooth and shining, without metatergal setae. Transverse metatergal sulci deep, line-shaped and present on all segments. Waist between pro- and metazonae relatively deep, striolate. Paraterga present, but small, crest-shaped, lying lower than metatergal surface. Pleurosternal carinae present as complete crests on segments 2-3, reduced to caudal teeth on segments 4-7, and missing on subsequent segments. Axial line missing.

Epiproct (Fig. 2B-D View Figure 2 ) broadly truncated, flattened dorsoventrally; tip with four spinnerets. Hypoproct subtriangular, with two distolateral, separated setiferous knobs (Fig. 2D View Figure 2 ).

Sterna sparsely setose, with distinct cross-impressions, without modifications except for a setiferous, broadly tongue-shaped lobule between coxae 4 (Fig. 3A, B View Figure 3 ).

Legs slender, long about 1.6-1.8 times as long as midbody height. Femora without modifications. Prefemora not swollen. Tarsal brushes absent.

Gonopods simple (Figs 3C-F View Figure 3 , 4 View Figure 4 , 5 View Figure 5 ). Coxite long, cylindrical, distoventral part sparsely setose. Prefemorite densely setose, set off from femorite by an oblique sulcus laterally. Femorite long, slender, without processes or modifications. The demarcation between postfemoral region and femorite present laterally. Lamina medialis of solenophore poorly developed while lamina lateralis well developed, with a tuberculiform process. Tip of gonopod broadly rounded lobule. Seminal groove running entirely on mesal side of femorite, then entering a flagelliform solenomere sheathed by solenophore.

DNA barcoding.

Fragments of COI and 16S rRNA genes were uploaded to GenBank with the accession numbers: MW647898 and MW648327, respectively. The new species has a close COI gene similarity with Orthomorphoides setosus (KU234720) of 87.17%. It also shares 74.04% and 72.68% of its 16S rRNA gene sequence with Asiomorpha coarctata (KU721885) and Pogonosternum nigrovirgatum (KU745218), respectively.

Etymology.

Named after Sapa, the type locality. It is a noun in apposition.

Remarks.

The genus Orthomorphoides was extracted from the genus Orthomorpha by Likhitrakarn et al. (2011) for two species: Orthomorpha setosa (Attems, 1937) and Orthomorpha exarata (Attems, 1953). The genus, therefore, currently contains only two species, Orthomorphoides setosus from Lam Dong Province (Vietnam) and Orthomorphoides exaratus from Xieng Khouang (Laos).

This new species obviously belongs to the genus Orthomorphoides because of its generic characters, such as: long and slender femorite without visible modifications and processes, and the solenomere being sheathed by a solenophore except for the exposed tip. The new species does, however, clearly differ from the two known Orthomorphoides species in body shape and the degree of development of the paraterga. In addition, the solenophore of the new species carries a tuberculiform process laterally while neither O. setosus nor O. exaratus possess additional processes on the solenophore.

The two previously described Orthomorphoides species were found only in high mountains in southcentral Vietnam and Xieng Khouang (>1500 m a.s.l.) ( Attems 1953). The discovery of this new species, found in Sapa, may further support the mountainous distribution of this genus, although this must be confirmed with additional field studies and possible discoveries.