Hyleoglomeris bomba Likhitrakarn, 2024

Hyleoglomeris bomba Likhitrakarn View in CoL ,

Sutcharit & Panha, sp. n.

Figs 9, 10

Holotype ♂ ( CUMZ-GLO096 ), Thailand, Chiang Rai Province, Wiang Chai District, Wat Tham Phakok (Wat Tham Phra Pha Ngam), outside cave area, elev. ca. 420 m a.m.s.l., 19°52’19“N, 100°02’41”E, 19/09/2022, leg. N. Likhitrakarn and P. Jirapatrasilp. GoogleMaps

Paratypes. 5 ♂♂, 3 ♀♀, 1 Juvenile ( CUMZ-GLO096 ) , 2 ♀♀ ( MUC-GLO096 ), same locality, together with holotype .

Name. To emphasize the body coloration with contrasting black and yellow bands, resembling the typical color pattern of a bum- blebee of the genus Bombus , a noun in feminine gender.

Diagnosis. This species closely resembles Hyleoglomeris suwannakhuhensis sp. n., but is distinguished by the colour of the thoracic shield and pygidium [almost yellowish or paler (fig. 9A–F) vs dark (fig. 7A, B) or almost dark (fig. 7C, E)], the colour of the venter and legs (predominantly dark (fig. 9E), vs almost yellowish or paler (fig. 7D), the number of striae along the lateral edge of the thoracic shield (8–10, vs 6–7), and the structure of the tip of the syncoxite lobe (sl) [spiniform and tapered tip (fig. 10E), vs a small bulbous projection (fig. 8E)]. Finally, the femoral process (fp) is different [narrowed subtrapeziform (fig. 8D), vs subtriangular (fig. 10D)].

Description. Body length of unrolled holotype, 8.5 mm, width 5.4 mm. Body length of unrolled paratypes, 6.2–8.2 mm (♂), 8.4– 9.3 mm (♀), width 3.8–5.1 (♂), 5.2–6.3 mm (♀).

Colour of live animals (fig. 9A–C): Body blackish, with contrasting broad light yellow to yellow bands along posterior edges of terga 3–11; width of bands approximately 1/3–2/3 height of each tergum; axial stripe yellow and extending fully across terga 3–7, and then gradually reduced in length on following terga (fig. 9A–C), thoracic and anal shields (= pygidium)

yellow to light yellow (fig. 9A–C). Head, collum and antennae black to dark brown; only labrum and Tömösváry’s organ brownish. Collum with contrasting yellow bands at caudal edge; venter and legs dark brown to black with a pale yellowish posterior part of each tarsus and claw. Colour faded after one year of preservation in alcohol (fig. 9D–F), body of preserved specimens black to dark brown, with contrasting pale yellow to whitish bands; axial stripe faded or extending 1/4 its height to middle. Head and antennae dark brown to black; venter and legs dark brown to brownish (fig. 9E).

Labrum sparsely setose (fig. 9E). Gnathochilarium with 2 + 2 palps of nearly equal length. Eyes blackish, comprising 8 + 1 ommatidia, cornea highly convex and translucent. Antennae with four evident apical cones, antennomere 6 approximately 2.3–3.1 times as long as its height (fig. 9A, C, E). Tömösváry’s organ typical, horseshoe-shaped, suboval, approximately 1.5–1.7 times longer than wide (fig. 9E).

Collum normal, with two transverse striae. Thoracic shield with a small hyposchism field not projecting behind tergal margin (fig. 9A, F). Striae 8–10, mostly superficial, only lower 2–3 lying above schism, one level to schism, remaining 5–6 below schism, with 5–6 complete and crossing the dorsum (fig. 9A). Terga 3 and 4 relatively broadly rounded laterally (fig. 9A, F). Following terga in front of pygidium faintly concave medially at caudal edge and with three or four striae starting above lateral edge, sometimes the first and second striae fading out at midway. Pygidium very faintly concave medially at caudal edge (fig. 9B, D).

♂ legs 17 (fig. 10A) simple, rather strongly reduced, with a rather low to medium-sized, often rounded coxal lobe (cxl) and a 4-segmented telopodite.

♂ legs 18 (fig. 10B) simple, slightly reduced, without any evident outgrowths. Syncoxite membranous, with a small, broadly archshaped syncoxite notch (sn) and a 4-segmented telopodite.

Telopods (= ♂ legs 19) (fig. 10C–E) with a small, subrectangular, rounded syncoxite lobe (sl)flanked by two elongated, spiniform, setose syncoxite horns (sh) tapering at tip, these being notably higher than syncoxite lobe (fig. 10C, D). Telopodite 4-segmented, with a spine apically. Prefemur (fig. 10C) subtrapeziform, with a conspicuous, elongated, robust, tuberculiform, distomesal prefemoral trichostele (pft); in anterior view with a rounded tip, extending apically to approximately half or to distal boundary of femur (fig. 10C). Femur (fig. 10D) subtrapeziform, with a stout, relatively short femoral trichostele (ft) in anterior view, extending apically to approximately 1/2–3/4 length of prefemoral trichostele and a rounded, slightly narrowed, subtrapeziform femoral process (fp), in posterior view strongly anterolaterad curved and gently tapering into an acuminate tip pointing distad (fig. 10D). Tibia stout, gently tapering distad and curved basad towards femoral process, with a small, distolateral tibial process (tp) strongly curved mesad (fig. 10C, D). Tarsus the smallest, subcylindrical, moderately sigmoid, strongly curved, narrowly rounded apically, with a robust and small terminal seta (fig. 10C, D).

DNA barcode. Hyleoglomeris bomba sp. n. seems to be sister to H. tongkerdae sp. n. with strong support (0.99 bpp for BI and 98% for ML). Yet it differs genetically from H. tongkerdae sp. n. by an interspecific COI divergence of 10.77% (table 2).

Remarks. The above new species shows a colour pattern that is superficially very similar to that of Hyleoglomeris pulchra Attems, 1953 . However, H. pulchra was described from a single female specimen collected at Pak Lai, Xayaburi Province, Laos (Attems, 1953), which geographically lies far away from the type locality of our new species (over 230 kilometers). Given this significant difference in geographic distribution, coupled with the limitations inherent in comparisons based on a single specimen of H. pulchra , we suggest the two species being different. Further examination of additional specimens from both localities, particularly males for comparisons of genitalic structure and/or molecular data, would be necessary to conclusively confirm this suggestion.

The type locality has topographical features consisting of undulating limestone hills and is still densely forested, providing suitable environments for a diverse range of terrestrial fauna such as various groups of land snails and millipedes. The type locality is surrounded by extensive agricultural areas, emphasizing the urgent necessity for comprehensive conservation initiatives to protect the distinct and delicate ecosystem that flourishes within its constraints.