Phlogiellus khampheng Sriranan, Songsangchote & Chomphuphuang, 2025

Sriranan, Patipan, Songsangchote, Chaowalit, Sihavong, Odeth, Sayavongsa, Phoukhanh, Sidavong, Keolamphanh, Satakoun, Lilammone, Inkhavilay, Khamla, Chomphuphuang, Narin & Gabriel, Ray, 2025, A new species of Southeast Asian dwarf tarantula in the genus Phlogiellus Pocock, 1897, from Lao PDR (Theraphosidae, Selenocosmiinae), ZooKeys 1247, pp. 19-43 : 19-43

Phlogiellus khampheng Sriranan, Songsangchote & Chomphuphuang sp. nov.

Figs 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 A, B , 9

Type material.

Lao PDR: Holotype • ♂ ( NUoL 00058 – PKP 0001 ) . Paratypes • 1 ♂ ( NUoL 00058 – PKP 0002 ), • 4 ♀ ( NUoL 00058 – PKP 0003 , NUoL 00058 – PKP 0004 , NUoL 00058 – PKP 0005 , NUoL 00058 – PKP 0006 ), deposited at NUOL, Lao PDR: Pakse : Champasack Province (15°05'36.3"N, 105°48'56.2"E), elevation 265 m, 23 Aug. 2023, Patipan Sriranan, Chaowalit Songsangchote, Odeth Sihavong, Phoukhanh Sayavongsa, Keolamphanh Sidavong, Lilammone Satakoun, Wuttikrai Khaikaew, Paveen Piyatrakulchai and Narin Chomphuphuang leg.

Diagnosis.

Phlogiellus khampheng sp. nov. was included in Phlogiellus based on the presence of a strong single retrolateral keel on the male embolus and a third claw on leg IV. P. khampheng sp. nov. is classified in the Yamia group ( Kishida 1920) of Phlogiellus , similar to P. aper , P. birulai , P. brevipes , P. bundokalbo , P. daweiensis , P. longipalpus , P. moniqueverdezae , P. mutus , P. quanyui , P. raveni , and P. watasei due to the absence of maxillary lyra in female specimens. The P. khampheng sp. nov. differs from P. aper , P. birulai , P. brevipes , P. daweiensis , P. longipalpus , P. mutus , and P. watasei in having all metatarsal scopulae undivided, and differs from P. raveni and female P. bundokalbo in tarsal scopula division (divided on tarsus II, III and IV). The male P. khampheng sp. nov. differs from P. brevipes , P. daweiensis , P. moniqueverdezae , P. quanyui , P. raveni , and P. watasei , except P. longipalpus , by having a longer and more slender embolus with a distinct curve (Fig. 8 ). It can be further distinguished from P. moniqueverdezae by the narrower width at the base of the embolus. P. khampheng sp. nov. can also be distinguished from P. moniqueverdezae by geographical distribution with P. moniqueverdezae being found nearly 1,000 km away across the Gulf of Thailand. Furthermore, the male P. khampheng sp. nov. can be distinguished by the angle between the lowest and highest point of the embolus (ALH), which is 59 °, compared to 77 ° in P. longipalpus and 44 ° in P. moniqueverdezae (Fig. 8 ). The female of P. khampheng sp. nov. differs from all other species in the Yamia group in the shape of the female spermathecae (Except female P. aper does not have described) which are twin receptacles with sub-apical buds (Fig. 6 ).

Description.

Male. Holotype ♂ NUoL 00058 – PKP 0001 : Color dark brown in life (Fig. 2 A ). Total length 16.89 (including chelicerae); carapace 5.23 width, 6.29 length, 1.77 high; procurved deep fovea (Fig. 3 G ), 0.98 width; carapace dark brown, with cover of short, grayish white hairs dorsally, chocolate brown on lateral margins (Fig. 2 A ), Ocular tubercle 1.22 width, 0.75 length, Clypeus absent. PER slightly recurved and AER slightly procurved; eyes whitish, ALE larger than the round AME; AME 0.20 length 0.19 width; ALE 0.32 length 0.19 width; PLE 0.27 length 0.17 width; PME 0.21 length 0.15 width; eye interdistances: PME – PME 0.57; PME – PLE 0.04; PLE – PLE 0.83; ALE – PLE 0.13; ALE – PME 0.20; ALE – ALE 0.70; AME – PME 0.14; AME – AME 0.20; AME – ALE 0.08; and AME – PLE 0.27. Chelicerae 3.23 length, 2.18 width, dark brown with eight teeth (Fig. 3 A, B ), three horizontal rows with a series of needle form striker <40 (Fig. 3 C ), Labium dark brown, 1.17 width, 0.84 length with 211 cuspules. Maxilla dark brown, 1.13 width, 2.16 length with 114 cuspules, covered with orange setae on prolateral surface and maxillary lyra absent (Fig. 3 E ). Sternum dark brown, 2.70 width, 3.11 length with soft white hairs and strong dark hairs, with 3 pairs of sigillae present near lateral margin of coxa I, II, and III (Fig. 3 D ). Anterior pair 0.16 from sternal margin 0.07 width, 0.11 length; median pair 0.19 from sternal margin 0.10 width, 0.20 length; posterior pair 0.40 from sternal margin 0.17 width, 0.40 length.

Abdomen 5.06 width, 7.93 length dark brown covered with short dark brown and long grayish white hairs dorsally, ventrally, and laterally. Spinnerets dark brown, covered with dark brown, thin and long hairs (Fig. 3 F ); PMS 0.83 length, 0.30 width; PLS 3.74 length basal segment, median segment and apical segment (1.44, + 1.16, + 1.14), width (0.49, + 0.44, + 0.40). Legs dark brown, retrolateral and prolateral of femur covered with dark hair. coxa, trochanter, patella and tibia dark brown and covered with dark brown hairs, metatarsus dark brown, metatarsus leg I and II covered with short and long grayish white hairs (in apical tibia) (Fig. 2 A ). Spination: metatarsus III ventral 0–0 – 1 (apical), metatarsus III prolateral 0–0 – 3 (apical), metatarsus III retrolateral 0–0 – 1 (apical), metatarsus IV ventral 0–0 – 1 (apical), metatarsus IV prolateral 0–0 – 3 (apical), metatarsus IV retrolateral 0–0 – 1 (apical), Length of leg and palp segment show in Table 1 , tibial apophysis absent. Tarsal I, II, III with two claws and tarsus IV with three claws, teeth on claws absent. Scopula undivided on metatarsus. Scopula completely divided by row of long spines on tarsus III and IV, undivided on tarsus I and II. Pedipalps dark brown, covered with long and short grayish white hairs on tibia, two lobes dark brown scopula on cymbium, embolus and bulb light brown (Fig. 4 ).

Palp bulb and embolus (PBL + ELS) 1.82 length, palp bulb oval shape and partly concave, 0.90 width (PBW), 0.65 length (PBL). Embolus needle-like shape 0.42 width (EW), 1.17 length along a straight line with the bulb (ELS) and 1.33 embolus length along the curve (ELC), embolus thin, curve and twist on needle tip. Single longitudinal keel present (Fig. 4 A ). Palp bulb twisted at 59 ° angle between highest and lowest point of embolus (ALH) (Fig. 8 ). Ratios; ELC / PBL = 2.04, ELS / PBL = 1.8, EW / PBL = 0.64, ELC / EW = 3.16 and ELS / EW = 2.78.

Female. Paratype ♀, NUoL 00058 – PKP 0003 : Color chocolate brown in life, carapace brown (Fig. 2 B ). Total length 20.92 (including chelicerae); carapace 4.42 width, 6.70 length, 2.76 high; procurved deep foveal, 1.10 width; carapace brown with a cover of short, whitish hairs dorsally, chocolate brown on lateral margins (Fig. 2 B ). Ocular tubercle 1.15 width, 0.86 length, Clypeus absent. PER slightly recurved; AER slightly procurved; eyes whitish, ALE larger than the round AME; AME 0.20 length 0.21 width; ALE 0.31 length 0.16 width; PLE 0.22 length 0.15 width; PME. 0.24 length 0.13 width; eye interdistances: PME – PME 0.52; PME – PLE 0.05; PLE – PLE 0.93; ALE – PLE 0.12; ALE – PME 0.15; ALE – ALE 0.66; AME – PME 0.10; AME – AME 0.11; and AME – ALE 0.05. Chelicerae 3.48 length, 270 width, dark brown with nine teeth, three horizontal rows with a series of needle form striker <40 (Fig. 5 A, B ). Labium dark brown, 1.33 width, 0.91 length with 260 cuspules. Maxilla dark brown, 1.36 width, 2.22 length with 133 cuspules, covered with orange setae on prolateral surface and maxillary lyra absent. (Fig. 5 C ). Sternum dark brown, 2.72 width, 3.21 length with soft white hairs and strong dark hairs, with 3 pairs of sigillae present near lateral margin of coxa I, II and III, anterior pair 0.81 from sternal margin 0.09 width, 0.11 length; median pair 0.20 from sternal margin 0.10 width, 0.20 length; posterior pair 0.50 from sternal margin 0.14 width, 0.31 length.

Abdomen 6.05 width, 10.13 length, dark brown covered with short dark brown and long grayish white hairs dorsally, ventrally, and laterally. Spinnerets dark brown, covered with dark brown longer and thinner hairs; PMS 0.68 length, 0.34 width; PLS 2.80 length basal segment, median segment and apical segment (0.83, + 0.91, + 1.06), width (0.49, + 0.50, + 0.41).

Legs dark brown, retrolateral and prolateral sides of femur covered with dark hair. Coxa and trochanter dark brown and covered with dark brown hairs. Patella, tibia, and metatarsus dark brown and covered with short and long brownish white hairs (Fig. 2 B ) Spination: metatarsus III ventral 0–0 – 1 (apical), metatarsus III prolateral 0–0 – 3 (apical) (Fig. 7 A ), metatarsus III retrolateral 0–0 – 1 (apical), metatarsus IV ventral 0–0 – 1 (apical), metatarsus IV prolateral 0–0 – 3 (apical), metatarsus IV retrolateral 0–0 – 1 (apical). Length of leg and palp segment show in Table 2 . Tarsus I, II, III with two claws (Fig. 7 B ) and tarsus IV with three claws, teeth on claws absent (Fig. 7 C ). Scopula undivided on metatarsus. Scopula completely divided on tarsus II, III and IV, undivided on tarsus I. Scopula divided by row of long spines. (Fig. 7 D ).

Spermatheca twin receptacles with sub-apical buds present; basal 0.44 width, 0.43 high, sub-apical bud 0.33 width, 0.73 high; the tops of sub-apical buds are ridged and swollen.

Female. Paratype ♀, NUoL 00058 – PKP 0004 : Color chocolate brown (in life), carapace brown. Total length 20.46 (including chelicerae); carapace 4.12 width, 5.58 length, 2.12 high; procurved deep fovea, 0.75 width (Fig. 5 E ); carapace brown with a cover of short, whitish hairs dorsally, chocolate-brown on lateral margins. Ocular tubercle 1.07 width, 0.67 length. (Fig. 5 F ). PER slightly recurved and AER slightly procurved; eyes whitish, ALE larger than the round AME; AME 0.19 length 0.18 width; ALE 0.27 length 0.13 width; PLE 0.18 length 0.10 width; PME 0.17 length 0.11 width; eye interdistances: PME – PME 0.52; PME – PLE 0.05; PLE – PLE 0.84; ALE – PLE 0.13; ALE – PME 0.18; ALE – ALE 0.57; AME – PME 0.13; AME – AME 0.13; and AME – ALE 0.09. Chelicerae 2.89 length, 2.15 width, dark brown with nine teeth, three horizontal rows with a series of needle form striker <40, Labium dark brown, 1.14 width, 0.80 length with 229 cuspules (Fig. 5 D ). Maxilla dark brown, 1.21 width, 2.08 length with 109 cuspules, covered with orange setae on prolateral surface and maxillary lyra absent. Sternum dark brown, 2.43 width, 2.95 length with soft white hairs and strong dark hairs, with three pairs of sigillae present near lateral margin of coxa I, II, and III, anterior pair 0.13 from sternal margin 0.06 width, 0.11 length; median pair 0.20 from sternal margin 0.09 width, 0.18 length; posterior pair 0.40 from sternal margin 0.11 width, 0.27 length.

Abdomen dark brown 6.23 width, 10.60 length covered with short dark brown and long grayish white hirsute dorsally, ventrally, and laterally. Spinnerets dark brown, covered with dark brown longer and thinner hairs; PMS 0.73 length, 0.31 width; PLS 2.81 length basal segment, median segment and apical segment (0.85, + 0.90, + 1.06), width (0.49 + 0.53 + 0.44).

Legs dark brown, retrolateral and prolateral of femur covered with dark hair. Coxa and trochanter dark brown and covered with dark brown hairs. Patella, tibia, and metatarsus dark brown and covered with short and long brownish white hairs. Spination: metatarsus III ventral 0–0 – 1 (apical), metatarsus III prolateral 0–0 – 3 (apical), metatarsus III retrolateral 0–0 – 1 (apical), metatarsus IV ventral 0–0 – 1 (apical), metatarsus IV prolateral 0–0 – 3 (apical), metatarsus IV retrolateral 0–0 – 1 (apical), Length of leg and palp segment show in Table 3 . Tarsi I, II, III with two claws and tarsus IV with three claws, teeth on claws absent. Scopula undivided on metatarsus. Scopula completely divided on tarsus II, III, and IV, undivided on tarsus I. Scopula divided by row of long spines.

Spermatheca twin receptacles with sub-apical buds present (Fig. 6 A ); basal 0.30 width, 0.42 high, sub-apical bud 0.25 width, 0.74 high, the tops of sub-apical buds are ridged and swollen (Fig. 6 C ).

Distribution and natural history.

Phlogiellus khampheng sp. nov. specimens were collected from a mixed deciduous forest in the mountains near Pakse, Lao PDR. The habitat, situated at an elevation of 265 m, is characterized by a relatively open area with numerous boulders and cobbles. Large trees providing ample shade dominate the landscape. The spiders are opportunistic utilizing various microhabitats such as soil walls, under rocks (Fig. 9 B ), beneath timber, within cracks in timber (Fig. 1 E ), and inside tree hollows. Some nests are also constructed in cavities under bamboo roots (Fig. 1 D ). A silk structure is often built around the entrance of their nests. In this environment, P. khampheng sp. nov. is frequently found near colonies of ants and termites. Remains of these insects are often discovered within their retreats, suggesting that ants and termites form a significant part of their diet. During the observation, a notably small female P. khampheng sp. nov. (non-type NUoL 00058 – PKP 0006 ♀) was encountered, measuring only 9.94 mm in total length from chelicerae to abdomen. This specimen was less than half the size of two paratypes: NUoL 00058 – PKP 0004 (20.46 mm) and NUoL 00058 – PKP 0003 (20.92 mm). Despite its diminutive size, this female was observed carrying an egg sac. Upon examination, the egg sac revealed a relatively low fecundity, containing only seven spiderlings (Fig. 9 A ) possibly due to age, with larger older females producing more young.

Etymology.

The species name “Khampheng” originates from the Lao and Thai languages, particularly in the Northeastern region, where it is used as a term of endearment to refer to someone who is cherished and precious to the speaker. The word carries a strong connotation of deep affection and high esteem, and it is often used in a loving and respectful manner when addressing or describing a person of great importance in one’s life. By choosing this name, the authors sought to convey the special and valuable relationship between Thailand and Laos, the two countries that collaborated closely in the discovery of this remarkable new tarantula species. “ Khampheng ” symbolizes the mutual respect, friendship, and cooperation that enabled the two nations to work together in advancing our understanding of the natural world and the incredible biodiversity it contains.

Figures

Figure 1. Locality of Phlogiellus khampheng sp. nov. A. Type locality; B, C. Habitat in the type locality, Pakse, Champasack Province, elevation 265 m; D. Habitat under a bamboo root cavity retreat. E. Habitat on timber.

Figures 2. Phlogiellus khampheng sp. nov. A. Holotype ♂, NUoL 00058 – PKP 0001; B. Paratype ♀, NUoL 00058 – PKP 0003.

Figures 3. Phlogiellus khampheng sp. nov. Holotype, ♂, NUoL 00058 – PKP 0001. A. Chelicerae, retrolateral view; B. Chelicerae, prolateral view; C. Chelicerae striker, retrolateral view arrowed; D. Sternum, ventral view; E. Right maxilla, prolateral view; F. Spinneret, ventral view, G. Foveal groove, dorsal view. Scale bars: 1 mm.

Figure 4. Phlogiellus khampheng sp. nov. Holotype, ♂, NUoL 00058 – PKP 0001 right palp. A. Retrolateral view; B. Ventral view; C. Prolateral view.

Figure 5. Phlogiellus khampheng sp. nov. A – C. Paratype ♀, NUoL 00058 – PKP 0003; D – F. Paratype ♀, NUoL 00058 – PKP 0004. A. Chelicerae, retrolateral view; B. Chelicerae, prolateral view; C. Right maxilla, prolateral view; D. Maxilla, labium and cuspules, ventral view; E. Foveal groove, dorsal view; F. Ocular tubercle. Scale bars: 1 mm.

Figure 6. Phlogiellus khampheng sp. nov. A. Paratype ♀, NUoL 00058 – PKP 0004: B, C. Paratype ♀, NUoL 00058 – KP 0005. A, B. Spermathecae, dorsal view; C. Spermathecae, apical view. Scale bars: 1 mm.

Figure 7. Phlogiellus khampheng sp. nov. Paratype ♀, NUoL 00058 – PKP 0003. A. Right tarsus III, prolateral view, arrow indicates spine on metatarsus; B. Right tarsus I, retrolateral view, claws of tarsus; C. Right tarsus IV, retrolateral view, arrow indicates third claws; D. Right tarsus III, ventral view, scopula divided, arrow indicates row of long spines Scale bars: 1 mm.

Figure 8. Angle of the lowest to highest point of male embolus (ALH). A. Phlogiellus khampheng sp. nov. holotype NUoL 00058 – PKP 0001 ♂, prolateral view; B. Phlogiellus khampheng sp. nov. paratype NUoL 00058 – PKP 0002 ♂, prolateral view; C. Phlogiellus moniqueverdezae ♂ Non-type C 6 – VA 1, prolateral view; D. Phlogiellus longipalpus ♂ Non-type B 1 – NA 1, prolateral view. Scale bars: 1 mm.

Figure 9. Phlogiellus khampheng sp. nov. A. Non-type NUoL 00058 – PKP 0006 ♀ adult carrying an egg sac; B. Subterranean system of silk tube retreats under rock.