Wernerius mumai Soleglad & Fet, 2008

Soleglad, Michael E. & Fet, Victor, 2008, Contributions to scorpion systematics. III. Subfamilies Smeringurinae and Syntropinae (Scorpiones: Vaejovidae), Euscorpius 71 (71), pp. 1-115 : 88-89

W. mumai (Sissom, 1993) , comb. nov. W. spicatus ( Haradon, 1974) , comb. nov.

Distribution. USA (Mojave Desert of Arizona and California).

This rare genus (see map in Fig. 202 ) has a limited range based so far on the few specimens collected. W. spicatus has been found in the south-central area of the Joshua Tree National Monument in California. W. mumai has been collected on the Arizona side of the Colorado River, between Kingman and Parker, Arizona. Both species appear to be somewhat adapted to rocky outcrops, similar to the microhabitats of many small Serradigitus species.

Etymology. The new generic name (masculine) is a patronym honoring Austrian zoologist Franz Werner (1867–1939), author of an encyclopedic treatise on scorpions (Werner, 1934).

Diagnosis. Modification to basal pectinal teeth of female marginalized, missing sensorial area reduced to one or two teeth, not particularly swollen or elongated and showing some distal angling or ovoid; OD denticles not serrated, all observable the entire length of both chelal fingers; distal denticle not overly elongated or hook-like, “whitish patch” minimal or absent altogether; inner accessory denticles (IAD) absent; conspicuous subaculear spinoid tooth present; ventromedian (VM) carinae of metasomal segments I–II granular to serrate.

Discussion. In the original species descriptions of W. spicatus, Haradon (1974) , and W. mumai, Sissom (1993) , certain diagnostic characters used in our current study are not outlined. However, by combining the two descriptions of these closely related species, both inhabiting the Mojave Desert of California and Arizona and sharing a distinct spinoid subaculear tooth (unusual in the vaejovids, see discussion below), we can establish most of the missing data. For example, the genital operculum, chelicerae and leg tarsus armature are not discussed by Sissom (1993) for W. mumai but they are, in part, for W. spicatus : Haradon (1974: 23 – 24) states the genital operculum is “completely fused medially” and the cheliceral movable finger has “serrula along smooth inferior margin, not extending to apex”. Neither author discusses the distal spinule pairs of the leg tarsus, but McWest (2000, in his unpublished Master thesis) states there are three spinules on W. mumai , which we will interpret here as a single pair. Haradon (1974) does not describe the hemispermatophore of W. spicatus (only females were available) nor does he state the condition of peg sensilla on the basal pectinal teeth. Sissom (1993: 65, figs. 12 – 14), however, nicely illustrates the hemispermatophore and mating plug of W. spicatus and reports that the basal pectinal tooth of the female W. mumai is ovoid and lacks sensilla. Both authors do illustrate the trichobothrial pattern which are identical in the key positions discussed in this study: fixed finger trichobothria dsb and dst are distal to esb and est, respectively; distance between chelal ventral trichobothria V 1 | V 2 and V 2 | V 3 are roughly the same (V 2 | V 3 slightly shorter); trichobothrium Dt is located slightly proximal of palm midpoint, 0.424 – 0.429; Db is positioned ventral of digital (D1) carina; ib – it are located just proximal of basal inner denticle (ID); and patella trichobothrium v 3 is distal of et 3. In Sissom’s illustrations of the chelae, the “whitish patch” is shown though it is not mentioned specifically in the text. Although the chelal finger distal denticles are not reported enlarged or elongated by Sissom (1993: figs. 5, 10), the female illustrated by Haradon (1974: figs. 1, 3, 6) appears to have enlarged distal denticles. Sissom’s (1993) illustration of the hemispermatophore of W. spicatus conforms to that exhibited in Syntropinae (see Figs. 47–56 ): a well developed, slightly bifurcated, lamellar hook exaggerated by a conspicuous basal constriction. Though the ventral trough is not indicated, it is clear that the distal aspect of the lamellar hook is situated well distal of the former. The mating plug barb is smooth and the overall appearance of the base is quite similar to that found in tribe Stahnkeini ( Figs. 83–84 ).

Sissom (1993: 68) discusses the taxonomic placement of these two taxa stating that “… In light of the structure of the hemispermatophore, the earlier interpretation of V. spicatus as a member of the Vaejovis nitidulus group …. now seems inappropriate. V. spicatus and V. mumai seem more properly allied to Serradigitus (but not included therein) …”. We agree with this assessment, especially if the genital operculum of the female is fused medially as reported by Haradon (1974). It is clear that these two species belong in subfamily Syntropinae , based on the genital operculum of the female, the shape of hemispermatophore, trichobothrial pattern, in particular, the non-basal placement of the chelal ib – it trichobothria. Based on the lack of sensilla on the basal tooth of the female pectines, the smooth barb of the mating plug, the single pair of ventral distal spinules of the leg tarsus, and well developed serrula, these species belong to tribe Stahnkeini where they share, in part, characters common to the genus Gertschius . Of course, genus Wernerius is unique with its spinoid subaculear tubercle, considered here a synapomorphy for the genus. Until detailed analysis of the chelal finger dentition of these two species is conducted, especially the number of MD and OD denticles, exact nature of MD development, etc. The exact placement of Wernerius within Stahnkeini remains somewhat unclear (see phylogram in Figure 196 ).

Other vaejovids with subaculear tubercles. Francke & Ponce Saavedra (2005) named a new species of Vaejovis , V. kuarapu , from Michoacán, Mexico. Of particular interest, this species exhibited a distinct subaculear tooth on the telson. Francke & Ponce Saavedra (2005) discussed their new species in context with other vaejovids reported with a subaculear tubercle, spanning all of North America: Wernerius spicatus , W. mumai, Mojave Desert , USA; Vaejovis pattersoni , Baja California Sur, Mexico; V. chamelaensis , Jalisco, Mexico; V. acapulco , Guerrero, Mexico; and V. nayarit , Nayarit, Mexico. They also mentioned Serradigitus joshuaensis from Mojave and Sonora Deserts, USA, which exhibits a small subaculear tubercle (see Fet et al., 2006b: fig. 1). Interestingly, since Haradon (1974) originally compared W. spicatus with S. joshuaensis, Sissom (1993) contrasted the subaculear tubercles between the two, S. joshuaensis having a tubercle but not a spinoid tooth as seen in W. spicatus and W. mumai . To add further to this distinction, Francke & Ponce Saavedra (2005) contrasted the subaculear tubercle on V. kuarapu (and V. acapulco and V. nayarit ) as a spinoid tooth and W. spicatus and W. mumai as having a conical tooth.

Originally, Williams (1980: 65 – 66) placed Vaejovis pattersoni in the “eusthenura ” group, as he also did the species V. chamelaensis (Williams, 1986) . After viewing specimens Sissom (2000) moved V. pattersoni to the “mexicanus ” group. Francke & Ponce Saavedra (2005: fig. 12) show that trichobothria ib – it in V. chamelaensis are situated quite basal on the fixed finger, not adjacent to the basal inner denticle (ID), a characteristic of subfamily Vaejovinae . Also, the ventromedian (VM) carinae of metasomal segments I – IV in V. chamelaensis are granular, unusual for the genus Hoffmannius (i.e., the “eusthenura ” group). Consequently, we place V. chamelaensis in subfamily Vaejovinae . We agree with Francke & Ponce Saavedra (2005) that the Mexican species exhibiting the subaculear tubercle may be related. Based on their descriptions alone, all should tentatively be placed in subfamily Vaejovinae along with V. pattersoni . As far as a definite Vaejovis group affiliation, if any, we will defer on this until actual specimens are available for examination, but for this study they are placed in the “mexicanus ” group.

Figures

Figure 196: Phylogram showing the three current subfamilies of family Vaejovidae based on the results of this study. * Note, subfamily Vaejovinae (shaded), the default nominotypic subfamily for Vaejovidae, has not yet been revised and therefore only reflects the remaining taxa and their relationships as suggested by Stockwell (1989) and/or Soleglad & Fet (2005).

Figure 202: General distribution of scorpion subfamily Syntropinae (tribe Stahnkeini) in North America with the ranges of genera Stahnkeus, Serradigitus, Gertschius, and Wernerius delineated.

Figures 47–56: Right hemispermatophore, dorsal view, of genera of subfamily Syntropinae showing well developed lamellar hook. Dotted line indicates position of ventral trough. Tribe Syntropini: 47. Kochius hirsuticauda, Indian Gorge Canyon, ABDSP, California, USA. 48. Kochius cazieri, Cuatro Ciénegas, Coahuila, Mexico. 49. Thorellius intrepidus, Mexico. 50. Hoffmannius eusthenura, Cabo San Lucas, Baja California Sur, Mexico. 51. Hoffmannius waeringi, Vallecito Creek, Carrizo Badlands, ABDSP, California, USA. 52. Hoffmannius puritanus, Jasper Trail, ABDSP, California, USA. 53. Syntropis macrura (after Stockwell, 1989: fig. 218, in part). Tribe Stahnkeini: 54. Serradigitus wupatkiensis, Wupatki Ruins, Wupatki National Monument, Arizona, USA. 55. Stahnkeus subtilimanus, Vallecito Creek, Carrizo Badlands, ABDSP, California, USA. 56. Gertschius crassicorpus, paratype, Navojoa, Sonora, Mexico (after Graham & Soleglad, 2007: fig. 10, in part).

Figures 75–88: Representative hemispermatophore mating plugs of subfamilies Syntropinae, Smeringurinae, and Vaejovinae. Tribe Syntropini, note toothed terminus. 75. Thorellius cristimanus, Autlán, Jalisco, Mexico. 76. Kochius punctipalpi punctipalpi, Los Aripes, Baja California Sur, Mexico. 77. Kochius hirsuticauda, Indian Gorge Canyon, ABDSP, California, USA. 78. Kochius cazieri, Cuatro Ciénegas, Coahuila, Mexico. 79. Hoffmannius eusthenura, Cabo San Lucas, Baja California Sur, Mexico. 80. Hoffmannius puritanus, Jasper Trail, ABDSP, California, USA. 81. Hoffmannius confusus, Mesa, Arizona, USA. 82. Syntropis macrura (after Stockwell, 1989: fig. 228, in part). Tribe Stahnkeini, note smooth terminus. 83. Serradigitus wupatkiensis, ventral view, Wupatki Ruins, Wupatki National Monument, Arizona, USA. 84. Stahnkeus subtilimanus, ventral view, Vallecito Creek, Carrizo Badlands, ABDSP, California, USA. Tribe Smeringurini, note smooth terminus. 85. Paruroctonus silvestrii, Chihuahua Road, ABDSP, California, USA. 86. Paruroctonus boreus, Mercury, Nevada, USA. Subfamily Vaejovinae, note smooth terminus. 87. Pseudouroctonus minimus castaneus, Vista, San Diego Co., California, USA. 88. Pseudouroctonus williamsi, Santa Ysabel Reserve, San Diego Co., California, USA.