Pseudouroctonus maidu, a new species of scorpion from northern California (Scorpiones, Vaejovidae)

Abstract A new species of vaejovid scorpion from northern California, Pseudouroctonus maidu sp. n., is named and described. This new species appears to be most similar to Pseudouroctonus iviei (Gertsch & Soleglad, 1972) and Pseudouroctonus glimmei (Hjelle, 1972).


Introduction
Recent fieldwork in northern California has revealed the presence of a previously undescribed species in the vaejovid scorpion genus Pseudouroctonus Stahnke, 1974. To facilitate its inclusion in discussions of ongoing systematic and phylogeographic studies of Pseudouroctonus and its near relatives (Francke and Savary 2006, Bryson et al. 2013, Bryson et al. 2014, the new species is named and described herein. It represents the third species of Pseudouroctonus in California, all endemic to the state, and only the fourth new species of scorpion to be described from California in the past twenty years.

Materials and methods
Study specimens were preserved in 70% ethanol and examined and photographed at 6× to 30× magnification with a Wild MP5 stereo microscope. Specimens were photographed under ultraviolet light following Volschenk (2005) for illustrative purposes. Terminology for carination and hemispermatophore follows Williams (1980); trichobothrial terminology follows Vachon (1974). Measurements cited are standard ones used in scorpion systematics, as defined by Williams (1980), unless otherwise noted.  Comparative diagnosis. Members of this small to medium-sized, darkly pigmented species (Fig. 1) appear to be most closely related to Pseudouroctonus iviei (Gertsch & Soleglad, 1972) and Pseudouroctonus glimmei (Hjelle, 1972), which together form a distinct group within the genus. All three species can be distinguished from other Pseudouroctonus by the lack of a distinct ridge on the primary lamellar hook of the hemispermatophore (Figs 2-7; see also figs 28 and 29 in Williams and Savary 1991). Pseudouroctonus maidu differs from P. iviei in having a proportionately less elongate and significantly less inflated fifth metasomal segment and in having the second metasomal segment longer than wide (see Figs 8-10 and Table 1). Pseudouroctonus maidu differs from P. glimmei in having a more granular carapace (Figs 11 and 12), and in having a well-developed, coarsely granular internomedial carina on the pedipalp patella .

Taxonomy
Unlike other members of Pseudouroctonus, P. maidu, P. iviei and P. glimmei bear an elevated secondary lamellar hook on the hemispermatophore (Figs 2-5; see also figs 26 through 29 in Williams and Savary 1991). This feature is also present in members of the related genus Kovarikia Soleglad, Fet & Graham, 2014 from southern California, although members of that genus also exhibit a distinct ridge on the primary lamellar hook of the hemispermatophore (Figs 6 and 7; see also figs 22 through 27 in Williams and Savary 1991) that is lacking in P. maidu, P. iviei and P. glimmei.
Description. Based on the adult holotype female [CASENT 9057357]. Color: Base color uniform dark reddish brown with legs, chelicerae and underside of preabdomen slightly paler.
Distribution. Known only from the type locality near the confluence of North and Middle Forks of the American River in El Dorado County, California (see Fig. 20).
Natural history. Specimens were collected on 6 May 2013 and 23 September 2013. Two were found during the day on 6 May beneath rocks in moist leaf litter along a steep rocky drainage. The remaining specimens were collected by UV detection at night on 23 September. All were found on or near the bottom of a rocky embankment next to the highway. The area is characterized by oak-dominated woodlands on the drier south-facing slopes and mixed-conifer forest on the cooler north-facing slopes. Most P. maidu were found on north-facing slopes with scattered patches of moss-covered rocks. Pseudouroctonus iviei were common in drier rocky habitat with an abundance of oak leaf litter, and the two species were found in close proximity (within 0.5 m of each other) under rocks in a steep rocky drainage connecting the two types of habitat.