Isometrus (Reddyanus) petrzelkai, Kovařík, 2003

Kovařík, František, 2003, A review of the genus Isometrus Ehrenberg, 1828 (Scorpiones: Buthidae) with descriptions of four new species from Asia and Australia, Euscorpius 10 (10), pp. 1-19 : 10-11

Isometrus (Reddyanus) petrzelkai sp. n.

(Figs 4, 5, and 8, Table 1)

? Isometrus vittatus: Fage, 1933: 28 ; Fage, 1936: 181; Fage, 1944: 71; Takashima, 1945: 87.

? Isometrus (Reddyanus) vittatus: Vachon, 1976: 39 (in part) and 42; Fet & Lowe, 2000: 153.

Isometrus (Reddyanus) vittatus: Kovařík, 1994: 202 (in part); Kovařík, 1995: 188 (in part); Kovařík, 1997a: 9 (in part); Kovařík, 1998a: 37; Kovařík, 1998b: 112 (in part); Kovařík, 2001: 86.

? Isometrus basilicus: Le Xuan Hue et al., 1998: 7 .

TYPE LOCALITY AND TYPE REPOSITORY. Vietnam, 80 km NNE Saigon, prov. Dong Nai, valley Ma Da, Tri An dam ; FKCP.

TYPE MATERIAL. Vietnam, prov. Dong Nai, 80 km NNE Saigon, valley Ma Da, Tri An dam, 1♀ (allotypic paratype), 27.IV.1996, 2♂ (holotype and paratype), III .1998, leg. K. Petrželka, FKCP . Thailand, 20 mi. SE Chantaburi, 75 m., 1.VIII.1962, 1♂ (paratype), leg. E. S. Ross & D. Q. Cavagnaro, CASC .

ETYMOLOGY. Named after Karel Petrželka of Prague, who spent several years in Vietnam and collected the type specimens .

DIAGNOSIS: Total length 45 to 58 mm (males) and 37 mm (female). Male has longer metasomal segments and telson. Segments of pedipalps approximately same length in both sexes. Pedipalps and legs yellow with several small brown spots. Manus of pedipalps yellow, fingers black. Metasoma yellow with small brown spots namely in female, fifth segment darker than preceding. First metasomal segment bears 10 carinae, second through fourth segments bear eight carinae, fifth segment smooth, with only one ventral median carina in males and five carinae in females. Each dorsal metasomal carina terminates in a tooth that on first three segments of males may be somewhat larger than preceding granules. Telson elongate in males, shorter in females. Subaculear tooth large, rounded, dorsally with two pairs of granules and one median granule. Pectinal teeth number 13–16.

DESCRIPTION: The total length is 47 mm in the male holotype and 37.1 mm in the female allotype. A color photo of the holotype and paratype is in Kovařík (in press). Measurements of the carapace, telson, segments of the metasoma and segments of the pedipalps, and numbers of pectinal teeth are given in Table 1. There are 13–16 pectinal teeth in the males and 13 in the female. For the position and distribution of trichobothria on the chela of pedipalps see Fig. 8. Sexual dimorphism is manifested primarily in the length of the metasomal segments and telson (see Figs. 4 and 5 and Table 1).

COLORATION: The base color is yellow with brown spots. The chelicera is posteriorly reticulated and anteriorly as black as much of the fingers. The carapace and mesosoma are dominantly black with a yellow pattern that forms two incomplete longitudinal strips. The ventral side of the mesosoma and of pedipalps is yellow without spots. The femur and patella of pedipalps are dorsally and laterally yellow with several small brown spots. The manus of pedipalps is yellow and fingers are black. The legs have the same color and pattern as the femur and patella of pedipalps. The first to fourth metasomal segments of males are yellow to yellowish brown. Most of the male fifth metasomal segment (except the anterior margin) and telson are reddish brown. The female and the smallest male (CASC paratype) have yellow metasomal segments with several small dark spots and a larger dark spot on the fifth segment.

MESOSOMA AND CARAPACE: The carapace is without carinae but with large granules. The mesosoma bears one median carina and is granulated. The ventral side of the seventh segment bears two or four carinae and is granulated.

METASOMA AND TELSON: The first segment bears 10 carinae, the second through fourth segments bear eight carinae, and the fifth segment of males is smooth, with only one ventral median carina. This carina is present also on the telson, and on the first four metasomal segments is indicated as a dark line and several granules between the two ventral carinae. The fifth metasomal segment of the female bears five carinae. Each of the dorsal metasomal carinae terminates in a tooth that on the first three segments of males is somewhat larger than the preceding granules. The telson is elongate in males and shorter in the female (Figs. 4 and 5). The subaculear tooth is rounded, dorsally with two pairs of granules and one median granule.

PEDIPALPS: The femur and patella bear complete carinae and are granulated. Incomplete dorsal carinae are present also on the manus of both sexes. The sixth cutting edge of the movable fingers bears one external granule.

LEGS: The femur and patella bear complete carinae and are granulated. The legs are hirsute and without bristlecombs.

AFFINITIES. The described features distinguish I. petrzelkai sp. n. from all other species of the genus. They are recounted in the key below. Morphologically closest is I. brachycentrus Pocock, 1899 from India, which differs in darker coloration of namely metasomal segments, a shorter male telson, incompleteness of two ventral parallel carinae on the first three metasomal segments, and their absence on the fouth and fifth segments. I. petrzelkai sp. n. has these carinae well developed on the first four metasomal segments. I suspect in the past this species has frequently been mistaken for s I. vittatus , which however has a different coloration (the fifth metasomal segment is yellow), subaculear tooth with only one pair of granules and one terminal granule, and differs in a number of other characters.