Hyleoglomeris krasoon Likhitrakarn, 2024

Likhitrakarn, Natdanai, Jeratthitikul, Ekgachai, Sapparojpattana, Pichsinee, Siriwut, Warut, Srisonchai, Ruttapon, Jirapatrasilp, Parin, Seesamut, Teerapong, Poolprasert, Pisit, Panha, Somsak & Sutcharit, Chirasak, 2024, Six new species of the pill millipede genus Hyleoglomeris Verhoeff, 1910 (Diplopoda, Glomerida, Glomeridae) in Thailand revealed by DNA-barcoding, Contributions to Zoology 93 (4), pp. 289-323 : 314-318

Hyleoglomeris krasoon Likhitrakarn ,

Sutcharit & Panha, sp. n.

Figs 13, 14

Holotype ♂ ( CUMZ-GLO059 ), Thailand, Lampang Province, Mae Phrik District, Wat Tham Nam Pha Pha Ngam, elev. ca. 210 m a.s.l., 17°28’50“N, 99°10’03”E, 21/09/2022, leg. P. Jirapatrasilp.

Paratypes. 11 ♂♂, 7 ♀♀ ( CUMZ-GLO059 ) , 2 ♂♂, 2 ♀♀ ( MUC-GLO059 ), same locality, together with holotype .

Name. To emphasize the word “krasoon ” from the compound word “kingkeu krasoon” which means “pill millipede” in Thai, a noun in apposition.

Diagnosis. Its colour pattern resembles that of Hyleoglomeris tongkerdae sp. n., but this former new species differs in several key characteristics. The most notable distinction is the contrasting transverse band on terga 3–11 [along the anterior edges (fig. 13A–F, H), vs along the posterior edges (fig. 11A–F, H)]. Additionally, the colour of the collum [yellowish (fig. 13A–C, G, H), vs dark (fig. 11A, B, G, H)]. Moreover, the presence of axial stripes in the dark area (absent vs present) and the caudal edge of the anal shield [slightly concave medially (fig. 13F, G), vs very faintly concave (fig. 11F, G)] further support the distinctness of the two species compared.

Description. Body length of unrolled holotype, 7.6 mm, width 3.8 mm. Body length of unrolled paratypes, 5.8–8.3 mm (♂), 5.7– 8.2 mm (♀), width 3.6–4.9 (♂), 3.6–4.7 mm (♀).

Colour of live animals (fig. 13A–E): Body black to dark brown, with contrasting pale yellow to yellow, relatively wide bands positioned along anterior edges of terga 3–11; width of bands approximately 1/3–2/3 height of each tergum, without contrasting axial stripes in dark area (fig. 13A, B, D); lateral sides of terga 3–11 each with a pair of prominent sublateral markings in yellow to marbled yellow-brownish shades, typically reaching neither caudal nor lateral edges (fig. 13A–D); collum, thoracic and anal shields (= pygidium) yellowish to light yellow; anal shield with contrasting pale brown and broad bands along anterior edge. Head and antennae black to dark brown; labrum and Tömösváry’s organ brownish; venter and legs brown to light brown with claws and posterior parts of each tarsus pale yellowish. Colour faded after one year of preservation in alcohol (fig. 13F–H), body of preserved specimens dark brown to pale brown, with contrasting pale yellow to whitish bands. Head and antennae grey to black; venter and legs yellow-brown to pale brown (fig. 13G).

Labrum sparsely setose (fig. 13G). Gnathochilarium with 2 + 2 palps of equal length. Eyes blackish, 7–8(6)+1 ommatidia, cornea very convex and translucent.Antennae with four evident apical cones, antennomere 6 approximately 2.0–2.5 times as long as high (fig. 13A, G). Organ of Tömösváry typical, horseshoe-shaped, oval, approximately 1.1–1.3 times as long as broad (fig. 13G).

Collum usual, with two transverse striae. Thoracic shield with a small hyposchism field, not projecting behind tergal margin (fig. 13A, H). Striae 8–10, mostly superficial, only lower 3–4 lying above schism, one level to schism, remaining 4–5 below schism, 4–6complete and crossing the dorsum.Terga 3 and 4 broadly and laterally rounded (fig. 13A, H). Following terga in front of pygidium faintly concave medially at caudal edge and with two or three striae starting above lateral edge, first stria sometimes fading away mid-dorsally. Pygidium slightly concave medially at caudal edge (fig. 13F, G).

♂ legs 17 (fig. 14A, B) simple, moderately to strongly reduced, with a medium-sized to high and often rounded coxal lobe (cxl). The telopodite with four segments.

♂ legs 18 (fig. 14C) simple, slightly reduced, without any evident outgrowths. Syncoxite membranous, with a simple, small and narrowly ogival syncoxite notch (sn) and a 4-segmented telopodite.

Telopods (= ♂ legs 19) (fig. 14E–F) with a small, subrectangular, rounded syncoxite lobe (sl) flanked by two elongated, spiniform, obliquely truncate, setose syncoxite horns (sh), these surpassing syncoxite lobe in height (fig. 14D–F). Telopodite 4-segmented, with a spine apically. Prefemur (fig. 14D) subrectangular, with a conspicuous, elongated, robust, tuberculiform, distomesal prefemoral trichostele (pft); in caudal view with a rounded tip, extending to about half to distal boundary of femur (fig. 14D). Femur (fig. 14E) subtrapeziform, with a prominent, stout, relatively short femoral trichostele (ft), in the caudal view extending apically to approximately 1/2–3/4 length of prefemoral trichostele (pft), and in the caudal view with a rounded subtriangular femoral process (fp) curved anterolaterally and gently tapering into an acuminate tip pointing distally (fig. 14E). Tibia relatively strongly elongated, gently tapering distally and curved basad towards femoral process, with a small, distolateral tibial process (tp) strongly curved mesad (fig. 14D). Tarsus the smallest, subcylindrical, moderately sigmoid, strongly curved, narrowly rounded apically, with a robust and small terminal seta (fig. 14C, D).

DNA barcode. The differences observed in the molecular data provide robust evidence for the validity of this species.The interspecific divergence between Hyleoglomeris krasoon sp. n. and the nearest species, H. hongkhraiensis , amounts to 9.12% COI p-distance (table 2).

Remarks. The colour of H. krasoon sp. n. bears resemblance to that of H. tongkerdae sp. n.; however, the collection localities are 80 km apart (fig. 15). Furthermore, the differentiation observed in the molecular data provided robust evidence for the validity of both species compared.

Key to species of Hyleoglomeris presently known to occur in Thailand (based chiefly on ♂), modified after Likhitrakarn et al. (2015b): 1. Dorsum: orange, monochromatic (fig.

3A–J) …………...… H. dracosphaera sp. n.

‒ Dorsum:coloration not monochromatic,

variegated …………………………………….. 2 2. Thoracic shield and pygidium creambrown, each with a pair of dark spots,

not contrasting with cream-brown terga

3–11. ………………………….…... H. siamensis

‒ Thoracic shield and pygidium without a pair of contrasting dark spots........…… 3

3. Terga 3–11 yellowish to pallid at background, with a pair of dark triangles located at caudal border of each tergum, or mostly a dark background with yellow to greyish inverted triangles of axial stripes. Head and collum dark …......................……..…… H. hongkhraiensis

‒ Colour patterns different ……………….... 4

4. Terga 3–11 yellowish at background with contrasting dark patterns and markings .........……………………………………………....5

‒ Terga 3–11 dark at background with a lighter band or pattern ………………….... 6

5. Terga 2–11 with distinctive dark brown bands along caudal edges (fig. 2A, B) ………………………………………….. H. aurea Terga 3–11 with two contrasting pairs of dark paramedian circular patches at median margin and smaller dark circles on lateral sides (fig. 5A, C) …............…….……. H. nigromaculata sp. n.

6. Terga 3–11 with a contrasting lighter posterior band along caudal edges.……….. 7

‒ Terga3–11withoutacontrastingposterior band along caudal edges ………..……….. 9

7. Thoracic shield and pygidium almost entirely yellowish to pallid. ……………... 8

‒ Thoracic shield and pygidium almost dark with a yellowish band along caudal edges(fig.7A–E)………………………………... ………………… H. suwannakhuhensis sp. n.

8. Venter and legs dark, matching the background coloration of dorsum (fig. 9D–F). Telopod femoral process (fp) trapezoi- dal in shape (fig. 10C, D) …………….…….. ………………………………… H. bomba sp. n.

‒ Venter and legs lighter in contrast to the background coloration of dorsum (fig. 11F–H). Telopod femoral process (fp) triangular in shape (fig. 11C, D) ……. …………………………… H. tongkerdae sp. n.

9. Collum yellowish to pallid ………………10

‒ Collum dark. Thoracic shield almost entirely dark with a thin, yellow-whitish, axial stripe …………………..…. H. montana

10. Thoracic shield almost entirely yellowish to pallid…………………………………… 11

‒ Thoracic shield almost dark with a yellowish posterolateral corner ………………………………….…... H. albicollis

11. Terga 3–11 with a contrasting anterior band lacking contrasting axial stripes (fig. 13A–F, H) …………… H. krasoon sp. n.

‒ Terga 3–11 without a contrasting band, but a light axial stripe in dark area ……………………………………….... H. cremea