Hyleoglomeris halang Kuroda, Nguyen & Eguchi, 2022

Kuroda, Mai, Eguchi, Katsuyuki, Oguri, Emiko & Nguyen, Anh D., 2022, Two new cave Hyleoglomeris species (Glomerida, Glomeridae) from northern Vietnam, ZooKeys 1108, pp. 161-174 : 161

Hyleoglomeris halang Kuroda, Nguyen & Eguchi sp. nov.

Figs 1 , 2 , 3 , 4 , 5

Material examined.

Holotype. Vietnam: male, Cao Bang Province, Ha Lang District, Duc Quang commune, Quang Hoai village , Nguom Hang cave , 22.7208N, 106.6692E, 10 Oct 2020, coll. AD Nguyen, VD Dang & VT Mai (IEBR-Myr 898H) . Paratypes. Vietnam: 1 male, 1 female; Cao Bang Province, Ha Lang District, Duc Quang commune, Quang Hoai village , Nguom Hang cave , 22.7208N, 106.6692E, 10 Oct 2020, coll. AD Nguyen, VD Dang & VT Mai (IEBR-Myr 898P) ; 1 male, 1 female; Cao Bang Province, Ha Lang District, Duc Quang commune, Quang Hoai village , Nguom Hang cave , 22.7208N, 106.6692E, 15 March 2022, coll. AD Nguyen & DD Nguyen (IEBR-Myr 926) .

Diagnosis.

The species differs from its congeners in having a distinct body color pattern of white with oval-black spots on terga 4 and 5 and tadpole-shaped black bands on the thoracic shield and terga 6-9; telopods with a large, square/rectangular, slightly concave medially, sparsely setose, central syncoxital lobe; and syncoxital horns ~ 1.5 × as long as the lobe.

The new species can be keyed out at the 26th node in Golovatch et al. (2006), characterized by a thoracic shield and pygidium that are entirely or mainly light and whitish to brown, as well as spots or markings, when present, that is darker than the background. Thus, this species can be grouped with Hyleoglomeris triangulifera Attems, 1938 and Hyleoglomeris siamensis (Silvestri, 1917). However, its smaller size distinguishes it from both species (3.5 mm wide vs. 6.5 mm and 5.0 mm wide).

Etymology.

The new species is named after the Ha Lang District where the types were found. Noun in apposition.

Description.

Body length 6 mm, width of the second segment ca. 3.5 mm. Coloration shown as in Figs 2 and 3 . Generally white with a line of symmetrical, marbled, black, oval spots at terga 4 and 5, tadpole-shaped black bands on thoracic shield and terga 6-9. Anal shield white, with two laterally symmetrical triangular black spots.

Head. Ocelli 6+1; lenses convex, black contrasting against to a pale blackish background of the head. Tömösváry’s organs transverse and strongly horseshoe-shaped, ~ 2 × as wide and long. Antennae clavate apically; antennomere 6 large, ~ 2.5 × longer than wide; antennal tip with four large, apical sensory cones.

Collum semi-circular, with a very large marbled white spot in the center and two transverse striae; the other parts of the collum pale black. The thoracic shield has a narrow hyposchism, not reaching the caudal margin, with 12 superficial transverse striae, eight of which cross the dorsum.

Leg-pair 17 strongly reduced, 4-segmented with a high, regularly rounded, outer coxal lobe (Figs 3D , 5A ). Leg-pair 18 also reduced, but more developed in comparison with leg-pair 17, 4-segmented with a simple V-shaped syncoxital notch.

Telopods (Figs 4 , 5B-D ) with a large, quadrate, slightly concave medially, sparsely setose, central syncoxital lobe (syl) accompanying two setiferous horns (syh), each directed subventrad, 1.5 × longer than the syncoxital lobe, tip crowned with an apical setoid. Prefemur (pre) and femur (fe) with long trichosteles (pret and fet), prefemoral one (pret) longer than femoral one (fet). Prefemur without additional processes. Distomesal process of femur (dpf) large, long, straight, lamelliform; distal part tuberculiform and strongly curved down, directed laterodorsad. Tibia (ti) with a shorter triangular distolateral process (dpt). Tarsus (ta) slightly sigmoid anteriomesad, subacuminate apically with a seta distoventrally.

Variability.

Syncoxital horns can be 2.0 × longer than the syncoxital lobe, each horn directed ventromesad. Two trichosteles are almost of the same in length.

DNA barcode.

The COI barcode data (679 bp fragment of the COI) for the paratype was uploaded to GenBank under the accession numbers ON704753 and ON704754. The new species shares 86.98% and 85.89% of its identity with Hyleoglomeris lobus Nguyen, Sierwald & Marek, 2019 (MT749402) and Hyleoglomeris hoanglien Nguyen, Eguchi & Hwang, 2019 (MH248038), respectively.

Remarks.

This species is not a true cave inhabitant. However, it was discovered in the cave entrance (Fig. 1 ), and its body is less pigmented with large white areas, suggesting that this species is adapting to a cave-dwelling life.

Figures

Figure 1. A Hyleoglomeris halang Kuroda, Nguyen & Eguchi, sp. nov. B Nguom Hang cave, entrance zone. Images not to scale.

Figure 2. Hyleoglomeris halang Kuroda, Nguyen & Eguchi, sp. nov., holotype A whole body, lateral view, B dorsal view C collum, anterior view D ocelli, sub-anterior view.

Figure 3. Hyleoglomeris halang Kuroda, Nguyen & Eguchi, sp. nov., holotype A right antenna B hyposchism C pygidium, posterior view D leg-pair 17.

Figure 4. Hyleoglomeris halang Kuroda, Nguyen & Eguchi, sp. nov., holotype A telopods, anterior view B telopods, posterior view.

Figure 5. Hyleoglomeris halang Kuroda, Nguyen & Eguchi, sp. nov., holotype A leg-pair 17 B syncoxital lobe and syncoxital horns, posterior view C left telopod, posterior view D left telopod, anterior view. Scale bar: 0.1 mm. Abbreviations: syl = syncoxital lobe, syh = syncoxital horn, pref = prefemur, fe = femur, pret = prefemoral trichostele, fet = femoral trichostele, dpf = distomesal process of femur, ti = tibia, dpt = distolateral process of tibia, ta = tarsus.