Lychas santoensis, Lourenço, 2009

Lourenço, Wilson R., 2009, Scorpions collected in the island of Espiritu Santo (Vanuatu) and description of a new species of Lychas C. L. Koch, 1845 (Arachnida, Scorpiones, Buthidae), Zoosystema 31 (3), pp. 731-740 : 732-739

Lychas santoensis n. sp.

( Figs 2-5 )

MATERIAL EXAMINED. — Vanuatu. Espiritu Santo Island, Pénaoru, Camp I, 149.6931°S, 166.65665°E, 900 m, low dense humid forest, 16.XI.2006, C. Rollard, ♀ holotype. — Pénaoru, 149.6700°S, 166.6622°E, 1100 m, transition forest, 17.XI.2006, C. Rollard, ♀ paratype.

COMPARATIVE MATERIAL EXAMINED. — Lychas perfidus (original name Isometrus perfidus Keyserling, 1885 ) (= Archisometrus perfidus ): Fiji. Viti Levu – e Mus. Godeffroy. Kpt. Pöhl det., 20.II.1894, 3 paralectotypes, 1 ♀ (lectotype), 2 ♂♂ juveniles ( BMNH).

Isometrus variatus papuanus Thorell, 1888 : New Guinea. Yule, C. York (Somerset) leg. L. M. D’Albertis, 2 ♀♀, lectotype and paralectotype ( MCSN).

DIAGNOSIS. — Scorpions of moderate to small size, with respect to the genus, measuring 31 mm for females.General colouration reddish-yellow to reddish-brown with very intense blackish variegated pigmentation over the body and appendages. Carinae and granulations moderate to strong. Pectines small; pectinal tooth count 12 or 11 for female holotype and 10 or 11 for female paratype; fulcra absent or inconspicuous. Dentate margins of fixed and movable fingers of pedipalp chela with 6 or 7 (6 – see remarks) almost linear rows of granules; one very inconspicuous external accessory granule next to the most basal row of granules. Subaculear tubercle moderate, between rhomboid and spinoid in shape; ventral granules inconspicuous.

ETYMOLOGY. — The specific name refers to the Island of Espiritu Santo ( Vanuatu) where the new species was collected.

RELATIONSHIPS From its general morphology, Lychas santoensis n. sp. is certainly related to Lychas variatus papuanus (Thorell, 1888 ), described from Yule Island in New Guinea,but also to Lychas perfidus (Keyserling, 1885) , described from Viti Levu Island, Fiji. In fact, the new species appears to occupy an intermediate morphological position between the two other species, what is also consistent with their respective geographical areas of distribution. Lychas santoensis n. sp. can, however, be distinguished from the other two species by the following characters:1) darker overall colouration and a much more intense blackish variegated pigmentation on body and appendages; 2) distinct shape of the subaculear tooth, between rhomboid and spinoid; and 3) fulcra absent or inconspicuous (see also taxonomic remarks after the description).

DESCRIPTION BASED ON FEMALE HOLOTYPE AND PARATYPE

Colouration Generally reddish-yellow to reddish-brown with intense blackish variegated pigmentation. Prosoma: reddish-yellow, globally covered with blackish pigmented zones; eyes surrounded by black pigment. Mesosoma: tergites reddish-yellow with several blackish spots forming approximately three longitudinal strips.Venter yellowish, with dense variegated dark spots covering coxapophysis, sternum, genital operculum pectines and all sternites. Metasoma: segments reddish-yellow to reddish-brown intensely marked with blackish variegated spots. Ventral aspect of segments IV and V almost blackish.Vesicle reddish-yellow with intensely marked blackish spots; aculeus yellow at the base and reddish at its extremity. Chelicerae yellowish, intensely marked with blackish variegated spots which cover its entire surface; teeth reddish. Pedipalps: yellowish to reddish-yellow; femur and patella intensely marked with variegated blackish spots; chela yellowish with some blackish spots, much less marked than those of femur and patella; rows of granules on dentate margins of the fingers reddish. Legs yellowish intensely marked with blackish variegated spots.

Morphology Prosoma: anterior margin of carapace moderately to strongly emarginate. Carapace carinae moderate to weak; anterior median and posterior median carinae moderately developed;other carinae weak to obsolete. Intercarinal spaces moderately granular.Median ocular tubercle anterior to the centre of the carapace; median eyes separated by one ocular diameter.Three pairs of lateral eyes. Mesosoma: tergites I-VI with a median carina; weak to obsolete on I, moderate on II-VI. Tergite VII pentacarinate, with lateral pairs of carinae moderate to strong; median carinae present in proximal half, moderately developed.Intercarinal spaces with a moderately to strongly marked granulation; similar to that of carapace.Sternites with moderately to weakly marked granulations; spiracles rather short; sternite VII more intensely granulated than other sternites and with four carinae. Pectines moderately long to small; pectinal teeth count 12 or 11 in holotype and 10 or 11 for paratype; fulcra absent or totally inconspicuous. Metasoma: segments I and II with 10 carinae, crenulate; III and IV with eight carinae, crenulate. Segment V with five carinae; absence of any posterior spinoid granule on the dorsal carinae of segments I-IV. Dorsal furrows of all segments weakly developed and with some thin granulations; intercarinal spaces moderately granular.Telson moderately elongated and weakly granular, with one ventral and two lateral carinae; aculeus moderately curved; subaculear tubercle moderate and between rhomboid and spinoid in shape; ventral granules inconspicuous. Chelicerae with the dentition characteristic of the buthids ( Vachon 1963); two small but well distinct basal teeth on movable finger. Pedipalps: Femur pentacarinate;all carinae moderately crenulate.Patella with seven carinae, moderately crenulate; dorsointernal carinae with 6 or 7 spinoid granules. Chela with vestigial dorso-external carinae weakly crenulated, and no internal granules. Intercarinal spaces weakly granular on femur and patella; almost smooth on chela.Dentate margins on movable and fixed fingers composed of 6-7 (6) linear rows of granules; one very inconspicuous external accessory granule next to the most basal row of granules. Trichobothrial pattern type A, orthobothriotaxic ( Vachon 1974); dorsal trichobothria of femur in β (beta) configuration ( Vachon 1975). Legs: ventral aspect of tarsi with a brush-like group of setae.Tibial spurs present on legs III-IV, moderately to strongly developed; pedal spurs present on all legs; reduced on legs I and II.

Morphometric measurements See Table 1.

TAXONOMIC REMARKS 1) In the very precise diagnosis proposed by Vachon (1986) for the genus Lychas , the absence of fulcra is assumed to be observed only in very rare cases ( Vachon 1986: 845, statement number 8: “fulcres externes présents, ces derniers rarement absents”). In the subsequent, but very superficial diagnosis proposed by Kovařik (1997), fulcra are indicated as always present. This assumption by Kovařik (1997) seems, however, to be based on a previous statement by Sissom (1990). The absence of fulcra in Lychas santoensis n. sp. seems to bring further evidence to the observations done by Vachon (1986).

2) According to Vachon (1986), the dentate margins of movable finger of pedipalp bear a fundamental number of 6 linear rows of granules. In fact, the most distal row of granules is not included in the count. Since this distal row can be, in many cases, rather conspicuous, the actual number of counted rows of granules should be 7 instead of 6.

Figures

FIG. 2. — Lychas santoensis n. sp., ♀ holotype, habitus, dorsal aspect. Scale bar: 1 cm.

FIG. 3. — Lychas santoensis n. sp., ♀ holotype, habitus, ventral aspect. Scale bar: 1 cm.

FIG. 4. — Lychas santoensis n. sp., ♀ holotype: A, chelicera, dorsal aspect; B, dentate margin of movable finger, showing rows of granules; C-G, trichobothrial pattern; C, D, chela, dorso-external and ventral aspects; E, F, patella, dorsal and external aspects; G, femur, dorsal aspect. Scale bars: 1.5 mm.

FIG. 5. — Metasomal segment V and telson, lateral aspect: A, Lychas santoensis n. sp., ♀ holotype; B, L. perfidus (Keyserling, 1885), ♀ paralectotype; C, L. variatus papuanus (Thorell, 1888), ♀ lectotype. Scale bars: 1.5 mm.