Isometrus (Isometrus) maculatus (DeGeer, 1778)

Di, Zhi-Yong, Cao, Zhi-Jian, Wu, Ying-Liang, Zhu, Lin, Liu, Hui & Li, Wen-Xin, 2013, The scorpions of Hainan Island, China (Arachnida: Scorpiones), Euscorpius 153, pp. 1-22 : 4-7

Isometrus (Isometrus) maculatus (DeGeer, 1778)

( Figures 1–29; Tables 1–2)

Isometrus maculatus: Thorell, 1876: 8 ; Vachon, 1982: 90; Kovařík, 1997: 362.

Isometrus (Isometrus) maculatus: Vachon, 1972: 177 ; Vachon, 1976: 38; Kovařík, 1994: 197; Kovařík, 1995: 187; Kovařík, 1997: 8; Fet & Lowe, 2000: 147; Kovařík, 2003: 2–4 .

Isometrus (Isometrus) madagassus: Vachon, 1972: 177 ; Vachon, 1976: 38; Vachon, 1982: 90; Kovařík, 1994: 202.

Isometrus (Raddyanus) europaeus: Tikader & Bastawade, 1983: 286 .

Type locality and type repository: “ Suriname and Pennsylvania ” ; NHRS.

Material examined: Hainan: Lingshui District, IV/2007, Hui Liu and Yi-Bao Ma leg., 24 adult and 5 immature males, 41 adult females ( MWHU, Ar.- MWHU - HNLS0701–70 ); Sanya, VIII/2006, Hui Liu and Ying- Liang Wu leg., 5 adult females, 1 juvenile ( MWHU, Ar.- MWHU-HNSY0601–06 ) .

Diagnosis: Moderate to large size, measuring up to 60 mm in adult male and about 50 mm in adult females. General coloration yellowish to pale yellow with symmetrical blackish-brown patterns in both adults and juveniles. Carinae and granulations moderately marked. Carapace strongly emarginate, with an open V-shaped angle. Pectines moderately long; pectinal tooth count 16–19 in both sexes. Dentate margins of fixed and movable fingers of pedipalp chela with 7 almost linear rows of granules. Trichobothrium db on chela of pedipalp situated between trichobothria dt and et. Subaculear tubercle strongly developed and triangular, with two ventral granules.

Relationships: In its general morphology and coloration, Isometrus (Isometrus) maculatus resembles Isometrus (Reddyanus) hainanensis , described from Southeast region in Hainan Island. It can be distinguished from the latter species by the following char- acters: (i) trichobothrium db on chela of pedipalp situated between trichobothria dt and et, while in I. (R.) hainanensis it is situated between trichobothria e t and est; (ii) subaculear tubercle with two ventral granules, while in I. (R.) hainanensis subaculear tubercle has five ventral granules; and (iii) the total length of adult males about 60 mm and 50 mm in adult females, while in I. (R.) hainanensis it is about 50–55 mm and 30–35 mm, respectively.

Description: Based on male specimens from Lingshui District (Hainan Island).

Coloration: Generally yellowish to pale yellow. Prosoma: Carapace yellowish with blackish-brown patterns; eyes surrounded by black pigment ( Figs. 1, 5, 6). Mesosoma: Tergites yellowish with symmetrical blackish-brown stripes; Sternum, genital operculum, sternites III–VI, pectines yellowish, sternites III–VII yellowish with symmetrical brown patterns. Metasomal segments pale yellow, with some diffuse, brownish spots. Vesicle pale yellow; aculeus yellowish at base and reddish-brown at tip. Chelicerae pale yellow with brownish variegated spots; base of fingers pale yellow, rest of fingers blackish-brown, teeth reddish. Pedipalps pale yellow with brownish spots; chela fingers reddishbrown; rows of granules on dentate margins of fingers dark reddish. Legs yellowish with diffuse spots.

Prosoma: Tegument coarse. Surface of carapace coarsely granular with a few smooth patches. Anterior margin of carapace strongly emarginate, with an open Vshaped angle. Carapace carinae weakly developed. Median ocular tubercle anterior to the centre of the carapace with granules; median eyes separated by one ocular diameter. Three pairs of lateral eyes present on anteriorlateral portion with granular lateral ocular tubercles (some specimens with two eyespot pairs dorso-posteriorly and posteriorly respectively, see in Figs. 5–6).

Mesosoma: Tegument coarse. Tergites I–VI with a median carina; weak on I, weak to moderate on II–VI. Tergite VII with two lateral pairs of carinae moderate to strong; median carinae present in proximal half, moderately developed. Intercarinal spaces moderately granular. Sternum pentagonal with a genital operculum subtriangular. Sternites smooth and shiny. Pectines moderately long, tooth count 16–17 in the male, fulcra marked ( Fig. 16). Sternites III to VI smooth; VII with four granular carinae.

Metasoma: Tegument coarse with few granules. Segments I and II with 10 carinae, crenulate; III–IV with 8 carinae, crenulate. Segment V with five carinae. Dorsal furrows of all segments developed, smooth; intercarinal spaces very weakly granular to smooth. Telson very weakly granular, almost smooth with one vestigial ventral carina; subaculear tubercle marked and triangular, with 2 granules on the ventral surface.

Pedipalps: Tegument almost smooth. Femora with all carinae marked crenulate, intercarinal spaces without granules in ventral aspect and other aspects with few granules. Patella with seven crenulate carinae. Chela with obsolete carinae. Dentate margins on fixed and movable fingers composed of six linear rows of granules ( Fig. 25). Trichobothrial pattern type A, orthobothriotaxic ( Figs. 26, 27). For the position and distribution of trichobothria of the femur, patella and chela of pedipalps see Figs. 7–9, 22–24, 26–29.

Chelicerae: Tegument smooth. Tibiae with reticulated pattern, with dentition characteristic of buthids ( Figs. 12, 13); two small basal teeth on dorsal aspect of movable finger.

Legs: Tegument smooth except dorsal aspect of femora with granules. Femora with 2 granular carinae in internal aspect, 2 granular carinae in external aspect and 1 granular carina in dorsal aspect. Patellae with 1 dentate carina in internal, 1 granular carina in dorsal aspect and 3 granular carinae in dorsal aspect. Tibiae with few setae, without spurs. Basitarsi with some setae and two lateral pedal spurs. Tarsi ventrally with two rows of short setae. Tarsal ungues curved and hook-like.

Variation: Females coloration very similar to males. Sexual dimorphism: females differ from males ( Figs. 3– 4, 19–21, 22–26) in having bigger mesosoma, shorter pedipalps and metasoma. Measurements, see Table 1. Pectinal tooth counts, see Table 2.

Habitat: Under stones or bark.

Distribution: See Fet & Lowe (2000).