Sphaerobelum petramurum Srikampha & Srisonchai 2025, sp. nov.

Sphaerobelum petramurum Srikampha & Srisonchai, sp. nov. Figs 10, 11, 12, 14E, F, 15 I, J, 16 Type material. Holotype. Thailand • ♂ (MZKKU -MYR 0005) Khon Kaen Province, Phu Pha Man District, Ban Khao Wong, 16°38'30.5"N, 101°46'37"E, ca. 247 m. a. s. l., 23 June 2022, K. Srikampha, R. Srisonchai, and MZKKU students coll. Paratypes. Thailand • ♂, ♀ for SEM (MZKKU -MYR 0006), same data as holotype. • ♂, 2 ♀♀ (MZKKU -MYR 0006), same data as holotype, 16 May 2021. • 3 ♂♂ (MZKKU -MYR 0006), same data as holotype, 26 September 2021. • ♂, 2 ♀♀ (MZKKU -MYR 0006), same data as holotype, 23 September 2023. • 3 ♂♂, 8 ♀♀ (MZKKU -MYR 0006), same data as holotype, 8 October 2023. Additional material examined — non-type. Thailand • 3 ♂♂, 2 ♀♀ (MZKKU), Khon Kaen Province, Phu Pha Man District, Ban Sam Poep, 16°40'44.2"N, 101°52'10"E, ca. 277 m. a. s. l., 17 May 2021. K. Srikampha coll. • ♀ (MZKKU), Khon Kaen Province, Phu Pha Man District, Ban Sam Poep, 16°40'44.2"N, 101°52'10"E, ca. 277 m. a. s. l., 23 June 2022. K. Srikampha coll. • 2 ♂♂ (MZKKU), ♂ (CUMZ - MYR 0033), ♂ (NHM), ♂ (NHMD), ♂ (NHMW), ♂ (ZFMK), Khon Kaen Province, Phu Pha Man District, Wat Si Walee Sattha Tham, 16°39'18.0"N, 101°52'14.5"E, ca. 260 m. a. s. l., 1 June 2024. K. Srikampha coll. • ♀ (MZKKU), Khon Kaen Province, Phu Pha Man District, Wat Si Walee Sattha Tham, 16°39'18.0"N, 101°52'14.5"E, ca. 260 m. a. s. l., 14 September 2024. K. Srikampha coll. • 3 ♂♂, ♀ (MZKKU), Khon Kaen Province, Si Chomphu District, Wat Tham Saeng Tham, 16°50'31.0"N, 102°03'56.2"E, ca. 270 m. a. s. l., 27 May 2024. K. Srikampha coll. • 6 ♂♂, 4 ♀♀ (MZKKU), Khon Kaen Province, Si Chomphu District, Wat Tham Sing to Thong, 16°47'55.9"N, 102°02'49.3"E, ca. 360 m. a. s. l., 27 May 2024. K. Srikampha coll. • ♀ (MZKKU), Chaiyaphum Province, Khon San District, Mortagek Monastery, 16°30'17.0"N, 101°50'41.8"E, ca. 390 m. a. s. l., 16 July 2023. K. Srikampha coll. • ♂ (MZKKU), Chaiyaphum Province, Khon San District, Wat Tham Phaya Chang Phueak, 16°33'47.6"N, 101°51'36.3"E, ca. 320 m. a. s. l., 1 June 2024. K. Srikampha coll. Diagnosis. S. petramurum sp. nov. differs in the femur of the legs, in which only the apical margin carries a few teeth (no teeth or teeth at the entire margin in the other known Sphaerobelum species), a character only shared with S. bicorne Attems, 1938, S. bolavensis Wesener, 2019, S. nonghinensis sp. nov., and S. onyx sp. nov. S. petramurum sp. nov. differs from both S. bicorne and S. bolavensis in the presence of a “ hook ” on telopoditomere 4 of the posterior telopods. S. petramurum sp. nov. differs strongly in the colouration from both S. nonghinensis sp. nov. and S. onyx sp. nov. (greenish-bluish brown vs. black). S. petramurum sp. nov. shares only with S. clavigerum, S. hirsutum, S. laoticum, S. nonghinensis sp. nov., S. onyx sp. nov., S. schwendingeri, S. separatum, and S. splendidum the presence of a “ hook ” on telopoditomere 4 of the posterior telopods. This new species differs from S. clavigerum by having a single short or dot-like locking carina on the anal shield (vs. 3 × long), from S. hirsutum and S. separatum in the presence of glabrous tergites (vs. hairy). It also differs from S. laoticum and S. schwendingeri in the presence of apical dish carrying <60 apical cones and tergites greenish-bluish brown (vs. 81–86 in S. laoticum, 36–73 in S. schwendingeri, and tergites black), from S. splendidum in the presence of leg 2 with coxal process (vs. absent) and a long telopoditomere 2 of anterior telopod (vs. short, without process as long as telopoditomere 3), and from S. nonghinensis sp. nov. by having a greenish-bluish brown body colour (vs. almost black). It differs from S. onyx sp. nov. by the presence of 5–6 rows of marginal bristles and marginal bristles covering 3 / 4 of outer area (vs. 3–4 rows, 1 / 4 cover area). Description. Measurements: Male holotype; body length 29.1 mm, width (broadest) of thoracic shield 13.7 mm, of tergite 7 = 14.5 mm; height of tergite 7 = 8.5 mm. Males: body length = 25.7–25.9 mm; width (broadest) of thoracic shield = 13.0– 13.7 mm, of tergite 7 = 13.9–14.7 mm; height of tergite 7 = 8.3–8.9 mm. Females: body length = 29.7–30.5 mm; width (broadest) of thoracic shield = 14.5–15.3 mm, of tergite 7 = 15.3–16.2 mm; height of tergite 7 = 9.2–10.0 mm. Colouration (Fig. 10 A – G): Specimens in life greenish-bluish brown or light brown, shiny. Head and collum brown to dark brown. Antennae, thoracic shield, paratergites, anal shield, legs, and venter light brown. Midbody area of each tergite with a longitudinal bluish-green or brown stripe (band), becoming visible when the animal rolls up. Lateral margin of each tergite with a brown patch. Anal shield with a large triangular brown patch. Specimens in alcohol after 3 years slightly faded to pale greenish-bluish brown. Head (Fig. 11 A, E): Trapeziform; densely setose in anterior part and sparsely setose in posterior one; each seta located inside small pit. With 66–83 ommatidia (ocelli) in males and 54–79 in females. Aberrant ommatidium and organ of Tömösváry as in S. nonghinensis sp. nov. and S. onyx sp. nov. Antennae (Figs 10 B, C, 11 B – D): Quite short and slender; covered by long and dense setae; last antennomere reaching back to leg pair 2 or 3. Lengths of antennomeres 6> 1 = 2 = 3 = 4 = 5 Antennomere 6 rounded apically; oval; apically with sensilla basiconica. Apical disc slightly convex, with 49–56 apical cones in male or 27–32 in female. Epipharynx (Fig. 11 F): With a regular central tooth (ct); laterally with numerous external teeth (et), short and sharp; inner area of each side with a row of delicately dentate spines (rsp). Gnathochilarium (Fig. 11 G, H): Structure typical as for Sphaerotheriida. Lamellae linguales (ll) rectangular, apically truncate. Central pads (Cp) modified, with numerous sensory cones. Stipites (st) large; densely setose; located laterally to lamellae linguales. Mentum (me) large; fused at base; with dense and long setae. Lateral palpi inconspicuous. Inner palpi (ip) with sensory cones (sc) arranged in three fields (clusters). Mandibles (gnathal lobe) (Fig. 11 I): With undivided external tooth (Et) and with conspicuous 3 - combed inner tooth (3 it). With 5–6 rows of pectinate lamellae (pl). Inner area (Ia) with group of tiny teeth. Molar plate (mp) flat, velvet-like; lacking a membranous fringe. Condylus (co) apically with two or three ridges. Tegument (Fig. 10 A – G): Shiny; all tergites sparsely microscopic setose; each seta located in an inconspicuous pit. Anterior margins of midbody tergite and anal shield with a few rows of long setae. Collum (Figs 10 B, C, 11 A): Subsemicircular; tip of lateral margin obtuse; sparsely long setose at margin. Thoracic shield: Anteriorly with shallow and large grooves separated by a long ridge. Groove and ridge smooth, without setae. Sloped towards groove laterally with 4 inconspicuous keels. Midbody tergite: With a row of oval impressions at anterior margin. Tips of midbody paratergites projecting posteroventrad. Paratergites: Paratergites 3 and 4 slender, slightly attenuate; tip sharp. Paratergites 5–12 wide; tip obtuse. Anal shield: Slightly sexually dimorphic; large and well-rounded in female, slenderer in male. Underside with a single, black locking carina; twice as long as length of tergites. Endotergum of midbody tergite (Fig. 14 E, F): Posterior margin (pm) unmodified, flat, regular. Outer area (oa) quite wide; smooth, without setae. Marginal bristles arranged in three or four rows; tips of the longest bristles not protruding above posterior margin. Middle area (ma) with a single row of conspicuous, wavy impressions; distance between impressions twice as long as individual diameter. Inner area (ia) without tubercles or setae. Pleurites (laterotergites) (Fig. 12 D): First pleurite slender, boomeranglike; apical margin attenuated, strongly projecting into a wide tip. Pleurite 2 wider than the first one, protruding into obtuse tip. All remaining pleurites flat and broad, apical margin slightly extended. Subanal plate (Fig. 12 H): Densely setose; broad and wide; subsemicircular; apical margin slightly concave. Stigmatic plates (Fig. 12 C): First stigmatic plate trapeziform, apex rounded. Second stigmatic plate in both sexes not curved. Legs (Fig. 12 A – G): All podomeres sparsely setose. Coxa (cx) large; coxal process absent in first legs; each side of legs 4–21 marginally with a large, dentate ridge. Prefemur (pre) quite short; apico-mesally with a weak projection. Femur (fe) 1.8 times longer than wide, with long ridge in all leg pairs; apico-mesally with inconspicuous dentate margin, carrying inconspicuous teeth (Sp). Postfemur (po) and tibia (ti) short. Tarsus (ta) of midbody legs quite long, 4 times longer than wide, as long as length of femur + postfemur; first two leg pairs without an apical spine; leg-pair 1 with 2 ventral spines; leg-pair 2 with 4 or 5 ventral spines; leg-pair 3 with 6 or 7 ventral spines and 1 apical spine; leg pairs 4–21 with 6 or 7 ventral spines and 1 apical spine. Claw normal, with a small notch at base. Male gonopore (Fig. 12 F): Small, triangular; covered by long setae. Anterior telopods (Fig. 13 A, C, E – G): First telopoditomere rectangular, slender, width <height. Telopoditomere 2 large, longer than telopoditomere 1. Immovable finger (process of telopoditomere 2) long and slender, longer than telopoditomere 3, clearly seen in posterior and ventral views, strongly curved; tip obtuse, apically with several sclerotised spots. Telopoditomere 3 longer than telopoditomere 4, distinctly demarcated from telopoditomere 4 by suture when seen in ventral view, apically with a single spine. Tepoloditomere 4 short, less than half as long as telopoditomere 3, with three spines (two spines located near base and one at apex); tip directed mesad. Posterior telopods (Figs 13 A – D, 15 I, J): Slender. Consisting of 4 telopoditomeres. First telopoditomere rectangular. Telopoditomere 2 large and long.