Scorpiops (Euscorpiops) krachan Nawanetiwong, Kosulic , Warrit, Lourenco & Ythier, 2024

Nawanetiwong, Wasin, Kosulic, Ondrej, Warrit, Natapot, Lourenco, Wilson R. & Ythier, Eric, 2024, A new species of the genus Scorpiops Peters, 1861, subgenus Euscorpiops Vachon, 1980 from Thailand (Scorpiones, Scorpiopidae), ZooKeys 1193, pp. 161-170 : 161

Scorpiops (Euscorpiops) krachan Nawanetiwong, Kosulic, Warrit, Lourenco & Ythier sp. nov.

Figs 1 , 2 , 3

Type locality.

Thailand, Phetchaburi Province: Kaeng Krachan National Park, Ban Krang Campsite, 12°47.970'N, 99°27.236'E, 324 m a.s.l., wet secondary forest (cloud-forest), 14 Nov. 2022, O. Košulič leg.

Type specimen.

Holotype, ♂. Original label: almost same as designation in type locality, deposited at the Muséum national d’Histoire naturelle, Paris, France. • Paratypes: 1 ♀. same data as holotype; 2 ♂. Original label: Thailand: Phetchaburi Province, Kaeng Krachan National Park, Ban Krang Campsite, 12°47.948'N, 99°27.250'E, 317 m a.s.l., wet secondary forest (cloud-forest), 14 Nov. 2022, O. Košulič leg., deposited at Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand (SCO-2022-005, SCO-2022-006).

Etymology.

The specific name refers to the National Park of Kaeng Krachan where the new species was collected.

Diagnosis.

The new species exhibits the general characteristics of the subgenus Scorpiops Euscorpiops ( Vachon 1980; Soleglad and Sissom 2001). Total length of male and female 21.7-26.9 and 25.9 mm, respectively, defining the new species as very small in comparison to most other species of the subgenus. General coloration brownish yellow; female darker than male; chelicerae yellow without any variegated spots. Pectines with 6-7 and 5-5 teeth in male and female, respectively; two marginal and two middle lamellae present; fulcra present. Sexual dimorphism strongly marked, with male pedipalps markedly elongated; chela length/width ratio 4.5-5.1 in male, 3.0 in female. Chelal fingers straight in both sexes; movable fingers with two parallel longitudinal rows of granules almost fused, formed by a row of about 50 median granules and a row of 19-20 inner granules (4-5) and inner accessory granules (15); 7-8 outer granules are present. Annular ring conspicuous in both sexes; telson length/depth ratio 2.6-2.8 in male, 2.6 in female. Trichobothriotaxy of type C ( Vachon 1974, 1980); three trichobothria on femur (dorsal, internal, and external); patella with two dorsal, one internal, six ventral, and 16(15) external trichobothria; chelal manus with four ventral, two dorsal (Dt, Db), two internal (ib, it), one Est, five Et, one Esb, and three trichobothria in the Eb series; trichobothrium Eb3 located in distal half of manus, between trichobothria Dt and Est.

Description.

Based on male holotype and female and male paratypes.

Coloration.

Basically yellowish to brownish yellow. Carapace brownish yellow, with paler zones posteriorly and on furrows. Tergites brownish yellow. Metasomal segments brownish yellow, darker in female; telson yellow; base of aculeus blackish and tip reddish. Chelicerae yellow, without any variegated spots; one blackish spot at the base of fixed finger; fingers brownish yellow, with reddish teeth. Pedipalps reddish brown to brownish, darker in female; fingers darker than chela manus, almost blackish. Legs yellow, intensely spotted with brownish. Venter yellow; coxapophysis, sternum and sternites markedly infuscated.

Morphology.

Carapace weakly granular, rather shagreened; furrows weakly deep. Median eyes anterior to the middle of carapace; three pairs of lateral eyes, the posterior one small in female and relictual in male. Sternum pentagonal, slightly longer than wide. Tergites weakly granulated, mostly shagreened; VII with five carinae, moderately marked; median carinae vestigial. Pectines large in male and reduced in female with a pectinal tooth count of 6-6 and 5-5, respectively; two marginal and two middle lamellae present; fulcra present. Sternites almost smooth and slightly punctated, with round spiracles; sternite VII with four vestigial carinae and some granulations, better marked in male. Metasomal segments I to V with 10-8-8-8-7 carinae; dorsal carinae on segments II-IV with several spinoid granules and one larger posterior spinoid granule; metasomal tegument weakly granulated; ventral carina on segment V with weakly marked spinoid granules. Telson vesicle with minute granulations, but largely smooth; annular ring conspicuous; telson length/depth ratio 2.6-2.8 in male, 2.6 in female. Setation moderate on metasomal segments and telson. Pedipalps: femur with dorsal internal, dorsal external, ventral internal and ventral external carinae moderately marked; tegument weakly granular. Patella with dorsal internal, dorsal external, ventral internal, ventral external, and external carinae weakly marked; one moderately to weakly marked spinoid granule present on internal aspect; tegument weakly granular. Chela with dorsal marginal, external secondary, ventral internal, and ventral carinae moderately marked; other carinae weak; tegument weakly granulated. Sexual dimorphism strongly marked with male pedipalps markedly elongated; chela length/width ratio 4.5-5.1 in male, 3.0 in female. Chelal fingers straight in both sexes; movable fingers with two parallel longitudinal rows of granules almost fused, formed by a row of about 50 median granules and a row of 19-20 inner granules (4-5) and inner accessory granules (15); 7-8 outer granules present. Cheliceral dentition as defined for the family ( Vachon 1963); a few teeth on ventro-internal face of movable finger. Trichobothriotaxy of type C, as shown in Fig. 2 ( Vachon 1974, 1980); three trichobothria on femur (dorsal, internal, and external); patella with two dorsal, one internal, six ventral, and 16(15) external trichobothria; chelal manus with four ventral, two dorsal (Dt, Db), two internal (ib, it), one Est, five Et, one Esb, and three trichobothria in the Eb series. Trichobothrium Eb3 distal in relation to Eb2 ( Vachon 1974, 1980), located in distal half of manus, between trichobothria Dt and Est. Legs tarsi with 4-5 long setae; tibial spurs absent.

Morphometric values.

Male holotype and female paratype of Scorpiops (Euscorpiops) krachan sp. nov. Total length including the telson 26.9/25.9. Carapace: length 4.2/4.1; anterior width 2.7/2.5; posterior width 4.2/4.2. Mesosoma length 8.6/9.8. Metasomal segments. I: length 1.3/1.2, width 1.7/1.5; II: length 1.6/1.4, width 1.5/1.3; III: length 1.8/1.6, width 1.4/1.2; IV: length 2.2/2.0, width 1.3/1.1; V: length, 3.6/2.9, width 1.1/1.0, depth 1.2/1.1. Telson length 3.6/2.9; vesicle: width 1.6/1.2, depth 1.3/1.1. Pedipalp: femur length 5.8/3.9, width 1.4/1.4; patella length 6.1/4.2, width 1.5/1.4; chela length 9.5/6.9, width 2.1/2.3, depth 1.8/1.9. Movable finger length 3.1/2.9.

Relationships.

The most similar species seem to be Scorpiops (Euscorpiops) phatoensis and Scorpiops (Euscorpiops) dunlopi , both described by Kovařík et al. (2020) from South Thailand (Fig. 4 ), notably based on size, number of pectine teeth, marginal and middle lamellae, shape of fingers, and number of external trichobothria on patella. Scorpiops krachan sp. nov. can, however, be separated from these two species by the following main features:

lighter coloration pattern (reddish brown to reddish black in S. phatoensis and S. dunlopi );

chelicerae without any variegated spots (variegated in S. phatoensis and S. dunlopi );

pectines with fulcra present (absent in S. phatoensis and reduced in S. dunlopi );

male chela slenderer than in S. phatoensis with length to width ratio 4.5-5.1 (3.7 in S. phatoensis );

chelal movable fingers with about 50 median granules (about 40 in S. phatoensis and 35 in S. dunlopi ), 4-5 inner granules (5-7 in S. phatoensis and absent in S. dunlopi ), 15 inner accessory granules (about 10 in S. phatoensis and 10-12 in S. dunlopi ) and 7-8 outer granules (absent in S. dunlopi );

female telson less elongated with length to depth ratio 2.6 in female (2.8-3.0 in S. phatoensis and 3.1 in S. dunlopi );

chelal manus trichobothrium Eb 3 located in distal half of manus, between trichobothria Dt and Est (located in middle of manus, at same level or distal to Dt in S. phatoensis );

an allopatric geographic distribution (type localities of S. phatoensis and S. dunlopi about 350 km and 500 km to the south, respectively).

Another species, Scorpiops (Euscorpiops) binghamii Pocock, 1893, described from southern Myanmar, is geographically close to S. krachan sp. nov. but can easily be distinguished from the new species, notably by the number of external trichobothria on patella (20-21), whereas S. krachan sp. nov. has 15-16.

Figures

Figure 1. Scorpiops (Euscorpiops) krachan sp. nov. A, B male holotype, habitus, dorsal A and ventral B aspects C, D female paratype, habitus, dorsal C and ventral D aspects. Scale bar 1 cm.

Figure 2. Scorpiops (Euscorpiops) krachan sp. nov. Male holotype, trichobotrial pattern A-C chela, dorso-external A ventral B and external C aspects D femur, dorsal aspect E-G patella, dorsal E external F and ventral G aspects. Scale bars 2 mm.

Figure 3. Scorpiops (Scorpiops Euscorpiops) Scorpiops Euscorpiops krachan sp. nov., alive with pre-juveniles (instar I).

Figure 4. Distribution map showing the type localities of the new species and its most relative Scorpiops species: S. (Euscorpiops) krachan sp. nov. (red triangle), S. phatoensis Kovarik et al., 2020 (green square), S. dunlopi Kovarik et al., 2020 (purple square).