Mesomexovis, González-Santillán & Prendini, 2013

González-Santillán, Edmundo & Prendini, Lorenzo, 2013, Redefinition And Generic Revision Of The North American Vaejovid Scorpion Subfamily Syntropinae Kraepelin, 1905, With Descriptions Of Six New Genera, Bulletin of the American Museum of Natural History 2013 (382), pp. 1-71 : 42-44

Mesomexovis , gen. nov.

Figures 2D , 6 , 7 , 19A, B , 27B ; table 1

Vejovis punctatus Karsch, 1879 [= Mesomexovis punctatus (Karsch, 1879) , comb. nov.], type species, here designated.

Vejovis first section (part): Hoffmann, 1931: 134, 139.

Vejovis eusthenura group (part): Williams 1970a: 395, 396.

Vaejovis eusthenura group (part): Williams, 1980: 55; Sissom, 1991: 26; Stockwell, 1992: 408, 409; Sissom, 1993: 68; Lourenço and Sissom, 2000: 135; Sissom, 2000: 530, 534, 535; Armas and Martín-Frías, 2001: 8; González-Santillán, 2004: 29; Ponce-Saavedra and Sissom, 2004: 541; Francke and Ponce-Saavedra, 2005: 67; Sissom and Hendrixson, 2005b: 33, 34; Fet et al., 2006a: 7; 2006b: tables 1 , 9; Graham and Soleglad, 2007: 9, 11, 12; Soleglad et al., 2007: 134, 135; McWest, 2009: 8, 48, 52, 56, 61, 64, 98, 101–103, 108 table 1 ; Santibáñez-López and Sissom, 2010: 49.

Vaejovis intrepidus group (part): Sissom, 1989: 180; 1991: 24, 26; Stockwell, 1992: 409; Sissom, 1993: 68; Lourenço and Sissom, 2000: 135; Sissom, 2000: 537, 538, 551; Armas and Martín-Frías, 2001: 8; Hendrixson 2001: 47; González-Santillán, 2004: 30, 31; Ponce-Saavedra and Sissom, 2004: 539, 541; Graham and Fet, 2006: 7; McWest, 2009: 66, 69, 70, 100–102, table 1 ; Santibáñez-López and Sissom, 2010: 52.

Vaejovis punctipalpi group (part): Francke and González-Santillán, 2007: 586, 587, 590; Graham and Soleglad, 2007: 11, 12; Soleglad et al., 2007: 134, 135.

Hoffmannius (part): Soleglad and Fet, 2008: 4 , 91, tables 3 , 5, 9; Ayrey and Soleglad, 2011: 1.

Kochius (part): Soleglad and Fet, 2008: 1 , 26, 30, 35, 57, 60, 66, 73, 92–95, 102, tables 4, 9; Ayrey and Soleglad, 2011: 1.

Thorellius (part): Soleglad and Fet, 2008: 1, 5, 30, 35, 53, 67, 73, 94, 95, 102, fig. 26, tables 1 , 4, 9; Ayrey and Soleglad, 2011: 1.

ETYMOLOGY: The generic name is a noun in apposition that combines three words, the Greek prefix ‘‘meso,’’ meaning ‘‘middle,’’ the first three letters of the country name ‘‘Mexico’’ and the last three letters of the genus Vaejovis , and is masculine in gender. The name refers to the distribution of the genus, which is endemic to the central states of Mexico, and to the original placement of its component species within the genus Vaejovis .

DIAGNOSIS: Species of Mesomexovis , gen. nov., are characterized by infuscate carinae on the pedipalp chela, patella, and femur. Infuscation of the chela dpl, plm, vrl, and vrs carinae is complete, extending the entire length of the manus, although ornamentation is absent, i.e., there is no difference in height or texture between these carinae and the adjacent intercarinal surfaces (fig. 19A, B). In contrast, the pedipalp patellar vrl and femoral rlds carinae are smooth and costate in most species of Mesomexovis , gen. nov. The vsm and vl carinae of metasomal segments I–IV are also markedly infuscate in most species of the genus, except M. atenango , comb. nov., as in some Chihuahuanus , gen. nov., and Paravaejovis species. However, species of Chihuahuanus , gen. nov., may be separated from Mesomexovis , gen. nov., by the presence of a small fusiform, whitish glandular area on the dorsal surface of the telson, near the base of the aculeus (fig. 26A), whereas most species of Paravaejovis may be separated by the pale and immaculate integument.

Additionally, the vl carinae are smooth and costate (sometimes obsolete), and the vsm carinae obsolete to absent, on sternite VII and metasomal segments I–IV, in most species of Mesomexovis , gen. nov. (fig. 27B). The ventral intercarinal surfaces of metasomal segment V are uniformly, finely granular (matte) to shagreened.

Mesomexovis , gen. nov., resembles Maaykuyak , gen. nov., in displaying similar patterns of infuscation on the carapace and tergites, as well as glabrous lateral intercarinal surfaces on metasomal segments I–V. The two genera may be separated by the presence of a medium-sized oval, whitish glandular area on the dorsal medial surface of the telson vesicle in Maaykuyak , gen. nov. (fig. 26B), which is absent in Mesomexovis , gen. nov.

Mesomexovis , gen. nov., shares with Kuarapu the completely infuscated rlds and rlm carinae of the pedipalp patella, but differs from Kuarapu in the shorter pedipalp chela fingers with relatively proximal trichobothria (fig. 19A, B; cf. fig. 18C, D), and the obsolete to absent vsm carinae of metasomal segments I–IV (fig. 27B; cf. fig. 24B).

INCLUDED SPECIES: Mesomexovis atenango ( Francke and González-Santillán, 2007) , comb. nov.; Mesomexovis oaxaca ( Santibáñez-López and Sissom, 2010) , comb. nov.; Mesomexovis occidentalis ( Hoffmann, 1931) , comb. nov.; Mesomexovis punctatus (Karsch, 1879) , comb. nov.; Mesomexovis spadix ( Hoffmann, 1931) , comb. et stat. nov.; Mesomexovis subcristatus (Pocock, 1898) , comb. nov.; Mesomexovis variegatus (Pocock, 1898) , comb. nov.

DISTRIBUTION: Mesomexovis , gen. nov., is endemic to Mexico, and has been recorded from 18 states on the mainland: Aguascalientes, Colima, Chiapas, Guanajuato, Guerrero, Hidalgo, Jalisco, Estado de México, Michoacán, Morelos, Nayarit, Oaxaca, Puebla, Sinaloa, Querétaro, Tlaxcala, Veracruz, and Zacatecas (fig. 6). The known distribution of this genus encompasses the mountain ranges of the Trans-Mexican Volcanic Belt, the valleys along the Pacific coast, extending from the southern limits of the Sierra Madre Occidental to the Isthmus of Tehuantepec and the Balsas Depression.

NATURAL HISTORY: Species of Mesomexovis , gen. nov., occur at the greatest range and the highest altitudes among Syntropinae , from sea level to 2600 m altitude, where they inhabit temperate and tropical deciduous forest and semidesert habitats. These scorpions appear to be maladapted to xeric conditions and are replaced by species of Chihuahuanus , gen. nov., and Paravaejovis in the northern part of mainland Mexico and the southwestern United States. Unlike Chihuahuanus , gen. nov., and Paravaejovis , Mesomexovis , gen. nov., exhibits a pronounced seasonal activity. Observations by the first author suggest that species of the genus are active during the rainy season, often becoming the numerically dominant species at particular localities, and estivate during the dry season, when the number of individuals active on the surface dwindles drastically. Due to this phenology, Mesomexovis , gen. nov., species are more commonly collected during the rainy season, by turning stones during the day and with UV light detection at night. The habitat and habitus are consistent with the lapidicolous ecomorphotype ( Prendini, 2001a).

REMARKS: This genus accommodates species previously assigned to the eusthenura , intrepidus , and punctipalpi groups of Vaejovis , first proposed by Hoffmann (1931), Williams (1970a, 1971a), and Sissom (1989). Soleglad and Fet (2008) devised the names Hoffmannius , Thorellius , and Kochius for these groups, respectively, without quantitatively testing their monophyly and composition. All three genera, as defined by Soleglad and Fet (2008), were consistently polyphyletic, and the group of species hereby assigned to Mesomexovis , gen. nov., consistently monophyletic, in the phylogenetic analyses of González-Santillán and Prendini (in press) based on DNA and those based on morphology and DNA. Mesomexovis atenango , comb. nov., was previously assigned to the punctipalpi group ( Francke and González-Santillán, 2007) and then to Kochius ( Soleglad and Fet, 2008) ; M. occidentalis , comb. nov., and M. subcristatus , comb. nov., to the intrepidus group ( Hoffmann, 1931; Sissom, 1989, 2000) and then to Thorellius ( Soleglad and Fet, 2008) ; and M. oaxaca , comb. nov., to the eusthenura group ( Santibáñez-López and Sissom, 2010).

González-Santillán and Prendini (in press) identified sufficient, consistent diagnostic character differences to elevate to species rank, M. spadix , comb. et stat. nov., formerly recognized as a subspecies of M. punctatus , comb. nov., and reinstate to its original rank as species, M. variegatus , comb. nov., also formerly considered a subspecies of M. punctatus , comb. nov. ( Hoffmann, 1931; Sissom, 2000).

MATERIAL EXAMINED: Mesomexovis atenango ( Francke and González-Santillán, 2007) , comb. nov.: MEXICO: Guerrero: Municipio de Copalillo: Totonimitla , Papalutla , 18 ° 01.4700 ′ N 98 ° 53.8092 ′ W, 650 m, 28.i.2011, U. Lonjino and J. Mendez, 18, 1♀ ( IBUNAM). Municipio de Tepecoacuilco de Trujano: Cerro de la Coronilla , 18 ° 0.9756 ′ N 99 ° 31.7256 ′ W, 844 m, 27.vi.2008, O.F. Francke, A. Quijano, and C. Santibáñez, 18, 1♀ ( IBUNAM); Cerro de la Coronilla, 3.4 km NE of Ahuehuepan , 18 ° 00 ′ 57 " N 99 ° 31 ′ 32 " W, 857 m, 23–24.x.2009, A. Valdez, T. López, and C. Quijano , 18, 1♀ ( IBUNAM). Mesomexovis spadix ( Hoffmann, 1931) , comb. et stat. nov.: MEXICO: Guanajuato: Municipio de León : León , iv.2004, P. Berea, 18, 1♀ ( IBUNAM). Mesomexovis oaxaca ( Santibáñez-López and Sissom, 2010) , comb. nov.: MEXICO: Oaxaca: Municipio de Ocotlán : Chichicapan , 4.8 km E, 1645 m, 23.viii.1966, C.M. Bogert, 18, 1♀ ( AMNH). Municipio de San Pablo Villa Mitla: Mitla , 8 km NE, on ridge ca. 6800– 7200 ft, near El Crucero ruins, 27.viii.1963, C.M. Bogert, G. Sluder, and N. Bucknall, 18, 1♀ ( AMNH). Municipio de Tlacolula de Matamoros: Tlacolula , 16.vii.1955, C. and P. Wauer, 18, 1♀ paratypes ( AMNH). Mesomexovis occidentalis ( Hoffmann, 1931) , comb. nov.: MEXICO: Guerrero: Municipio de Acapulco: Acapulco , holotype ♀ of Vaejovis subcristatus occidentalis Hoffmann, 1931 ( AMNH), H. Hoffmann, 18, 1♀ paratypes ( AMNH); Cumbres de Llano Largo , 16 ° 49.505 ′ N 99 ° 49.999 ′ W, 371 m, 19.vi.2007, O.F. Francke, H. Montaño, and A. Ballesteros, 18 ( CAS [ ARA 1975 ]). Municipio de Copala: Microwave antenna Fogos , E of Copala , 16 ° 33.9918 ′ N 98 ° 53.30 ′ W, 103 m, 22.vi.2007, O.F. Francke, H. Montaño, L. Escalante, and A. Ballesteros, 18, 1♀ ( IBUNAM). Mesomexovis punctatus (Karsch, 1879) , comb. nov.: MEXICO: Hidalgo: Municipio de Zimapán: Microwave antenna at Zimapán , 20 ° 44.7828 ′ N 99 ° 20.8998 ′ W, 1900 m, 3.viii.2002, L. Prendini, O.F. Francke, E. González, and J. Ponce, 28, 2♀ ( AMNH [ ARA 1170 ]). Mesomexovis subcristatus (Pocock, 1898) , comb. nov.: MEXICO: Oaxaca: Municipio de Cuicatlán: Tomellin , 17 ° 45.180 ′ N 96 ° 57.237 ′ W, 605 m, 23.vii.2002, L. Prendini, O.F. Francke, E. González, and J. Ponce, 18, 1♀ ( AMNH [ LP 2086]). Puebla: Municipio de Tehuacán: Tehuacán , 2 km E, 18 ° 24.002 ′ N 97 ° 22.867 ′ W, 1435 m, 25.vii.2002, L. Prendini, O.F. Francke, E. González, and J. Ponce, 18, 1♀ ( AMNH [ LP 2048]). Mesomexovis variegatus (Pocock, 1898) , comb. nov.: MEXICO: Guerrero: Municipio de Buenavista de Cuellar: El Comal , 18 ° 27.086 ′ N 99 ° 17.139 ′ W, 1749 m, 13.vi.2007, O.F. Francke et al., 18, 1♀ ( AMNH [ ARA 2623 ]).

Figures

Fig. 2. Representative habitats of species in the North American vaejovid scorpion subfamily Syntropinae Kraepelin, 1905. A. Cuatro Cienegas de Carranza, Coahuila, Mexico, habitat of Chihuahuanus cazieri (Williams, 1968), comb. nov., Chihuahuanus coahuilae (Williams, 1968), comb. nov., and Chihuahuanus globosus (Borelli, 1915), comb. nov. B. Death Valley, California, habitat of Kochius hirsuticauda (Banks, 1910). C. Isla Espiritu Santo, La Paz, Baja California Sur, Mexico, habitat of Kochius insularis (Williams, 1971), Paravaejovis diazi (Williams, 1970), comb. nov., and Paravaejovis gravicaudus (Williams, 1970), comb. nov. D. Cuicatlán, Oaxaca, Mexico, habitat of Mesomexovis subcristatus (Pocock, 1898), comb. nov. E. Pinacate desert, Sonora, Mexico, habitat of Paravaejovis confusus (Stahnke, 1940), comb. nov. F. West of La Paz, Baja California Sur, Mexico, habitat of Syntropis williamsi Soleglad et al., 2007. Photos in B and E courtesy of R. Mercurio and in C courtesy of I.G. Nieto.

Fig. 6. Map of southwestern North America, plotting known locality records for three genera in the vaejovid scorpion subfamily Syntropinae Kraepelin, 1905, based on data collected in the present study: Maaykuyak, gen. nov. (squares); Mesomexovis, gen. nov. (circles); Vizcaino, gen. nov. (triangles).

Fig. 7. Most parsimonious tree (length: 10894.593, CI: 0.190, RI: 0.628, fit: 244.08), obtained by simultaneous phylogenetic analysis of 250 qualitative and quantitative morphological characters and 4221 aligned DNA nucleotides from three mitochondrial and two nuclear gene markers, for 18 genera and 61 species in the North American vaejovid scorpion subfamily Syntropinae Kraepelin, 1905. Analyses were conducted with an implied weighting regime (k 518) that maximized average support (González-Santillán and Prendini, in press). Synapomorphies are optimized with accelerated transformation. Black bars indicate uniquely derived apomorphic states, white bars indicate parallel derivations of apomorphic states, numbers above indicate characters, and numbers below indicate states (appendix 1).

Fig. 19. Syntropinae Kraepelin, 1905, dextral pedipalp chela, dorsal (A, C) and retrolateral (B, D) aspects, illustrating carinae and distribution of trichobothria. A, B. Mesomexovis punctatus (Karsch, 1879), comb. nov., 8 (AMNH). C, D. Paravaejovis hoffmanni (Williams, 1970), 8 (AMNH). Scale bars 5 1 mm.

Fig. 27. Syntropinae Kraepelin, 1905, metasomal segments I–V and telson, ventral aspect, illustrating carinae. A. Chihuahuanus coahuilae (Williams, 1968), comb. nov., 8 (AMNH). B. Mesomexovis punctatus (Karsch, 1879), comb. nov., 8 (AMNH). C. Paravaejovis diazi (Williams, 1970), comb. nov., 8 (AMNH). Scale bars 5 2 mm.