Rhopalomeris nagao Nguyen & Nguyen & Eguchi 2021, sp. nov.
Creators: name: Nguyen, Anh D.
name: Nguyen, Son G.
name: Eguchi, Katsuyuki
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Diplopoda
Glomerida
Glomeridae
Rhopalomeris
Rhopalomeris nagao

description: Rhopalomeris nagao sp. nov.
(Figs 2–5)
Material examined. Holotype. 1 male (IEBR-Myr 854H) Vietnam, Cao Bang Province, Pia Oac – Pia den National Park, on the trail to the peak, near Lung Pham mining site, N22.6082 – E105.8693, elev. 1,600m, natural forest, 7 June 2020, leg. Anh D. Nguyen.
Paratypes. 3 males (IEBR-Myr 854P) same data as for the holotype; 1 male (IEBR-Myr 852) same locality as the holotype, but on the trail to Hang Ong, N22.5540 – E105.8622, elev. 850m, 8 June 2020, leg. Anh D. Nguyen.
Diagnosis. The new species can be recognized by the following combination of characters: antennal tip with numerous sensory cones; telopods with short prefemoral and femoral trichosteles, with long, straight and acute tuberculiform distomesal femoral process, and shorter lobuliform distolateral tibial process; syncoxial lobe being slightly concave medially; syncoxial horns being longer than lobe.
The new species differs from R. variegata Golovatch & Semenyuk, 2016 (from Highlands of Vietnam) and R. sauda Nguyen, Sierwald & Marek, 2019 (from northern Vietnam) in colouration (black colour plus several yellow spots (R. nagao sp. nov.) vs. variegated colour (R. variegata) vs. yellow colour plus black spots (R. sauda )). The new species also differs from R. sauda in length of trichosteles (short in R. nagao sp. nov. vs. long in R. sauda), shape of syncoxial lobe (slightly concave medially (R. nagao sp. nov.) vs. slightly convex medially (R. sauda )) and shape of femoral and tibial processes (long, straight and acute tuberculiform femoral process (R. nagao sp. nov.) vs. large tuberculiform process with bowed distal part (R. sauda); shorter lobuliform tibial process (R. nagao sp. nov.) vs. a long, sigmoid mesad, acute tuberculiform process (R. sauda )). Moreover, femoral process of telopods lacks a membranous apical sac which is clearly observed as in R. carnifex and R. variagata.
Another species, R. tonkinensis Silvestri, 1917, was described from female specimens, the male remains unknown. However, the new species is clearly distinguishable from R. tonkinensis by the colour pattern (black plus yellow spots vs. mostly black in R. tonkinensis), number of ocelli (7+1 vs. 8+1), and number of striae on thoracic shield (10–11 vs. 7).
Etymology. “ nagao ”, noun in apposition, refers to the Nagao Environmental Foundation of Japan which significantly contributes to the biodiversity inventory and conservation in Vietnam.
Description. Holotype length ca. 12.9 mm, width of thoracic shield ca. 5.4 mm.
Terga black with a yellow broad median line or yellow triangular median spot on terga 3–5, and with four yellow lateral spots forming two oval marbled spots laterally (Fig. 2A, B). Thoracic shield with similar color pattern to other terga, but smaller spots (Fig. 3A). Anal shield (= pygidium) with a yellow large triangular spot caudomedially (Fig. 3B).
Ocelli 7+1 (Fig. 2C), lenses convex, black contrasting against light brown background of head. Tömösváry organs transverse strongly horseshoe-shaped, 2X as long as wide (Fig. 2C). Antenna clavate, antennomere 6 largest and longest, 1.7–1.8X long as wide. Antennal tip with numerous apical sensory cones (Fig. 3C, D).
Collum semicircular, light brown, with a marbled yellow-brown, transverse oval spot in the middle, with two distinctly transverse striae (Fig. 2D). Second tergum with a narrow hyposchism, not reaching to caudal margin, with 10–11 striae; other terga with a stria distolaterally. Anal shield rounded, not concave medio-caudally (Fig. 3B).
Leg pair 17 strongly reduced, with 4 podomeres, with a high, regularly rounded outer coxal lobe; coxa with an apical setiferous spine (Fig. 4A); podomere 4 with an apical seta. Leg pair 18 also strongly reduced as legs of legpair 17, with 4 podomeres, with a simple V-shaped syncoxial notch (Fig. 4B).
Telopods (Figs 4C, D, 5) with a trapeziform, slightly concave medially, sparsely setose, central syncoxial lobe accompanying two setiferous horns, each directed ventrad, longer than syncoxial lobe. Prefemur and femur with short trichosteles. Prefemur without additional processes. Femur with a large, long, straight-directed and acute tuberculiform distomesal process. Tibia with a shorter lobuliform distolateral process. Tarsus slightly sigmoid anteriomesad, subacuminate apically, with a seta distoventrally.
Variation. Length from 11.1–15.5 mm, width of thoracic shield varies 5.4–7.8 mm. Two paratypes have 6+1 ocelli.
DNA barcode. COI barcode data (partial) for the paratypes has been uploaded to GenBank under the accession numbers MT749392 and MT749411. The new species shares 89.25% and 83.2% identity with Glomeridella minima and Trachysphaera sp., respectively.
description: Published as part of Nguyen, Anh D., Nguyen, Son G. & Eguchi, Katsuyuki, 2021, A new Rhopalomeris species (Diplopoda: Glomerida: Glomeridae), and notes on the phylogenetic relationships between glomeridans in Vietnam, pp. 257-264 in Zootaxa 4927 (2) on pages 259-263, DOI: 10.11646/zootaxa.4927.2.5, http://zenodo.org/record/4537077