Genus Chanbria Muma, 1951

Revised diagnosis

Chanbria are medium-sized eremobatids, with mature individuals ranging from 14 to 27 mm in length when measured from the distal tip of the abdomen to the distal-most portion of the chelicerae. They are generally a uniform light tan to yellowish in colour, with some individuals taking on a darker, sandy reddish brown that might be dependent on substrate association. Coloration is interspecifically variable among some species, notably among the pedipalps and legs of C. serpentinus, C. plicatus, and C. mapemes, hence these taxa are noticeably darker in overall coloration than C. regalis . Papillae are present on the palpal tarsi in all species; however, this character is absent in specimens of C. plicatus and C. regalis, possibly owing to habitat association. Leg I possess a single terminal claw (Supporting Information, Fig. S1A, B). The female genital opercula vary both inter- and intraspecifically (Fig. 7A–D), with simple lobate, thin, angular, triangular, or broad anterior pillars, with laterally curving lobes. Dentition on the FF of the male chelicerae is heavily reduced or absent distally, but present proximally in C. regalis and C. mapemes (Fig. 7). The MF of the male chelicerae displays a prominent, recurved proximal tooth, with MSM, an MM, and MST, except in C. plicatus . Female chelicerae are noticeably anteroposteriorly elongate and dorsoventrally slim in comparison to other eremobatids.Females also display between seven and nine teeth on the FF (Supporting Information, Fig. S2). Except for C. mapemes, Chanbria lack ctenidia. Synapomorphies for Chanbria include a distinctively shaped MF of the male chelicerae that forms the shape of an exponential curve (Supporting Information, Fig. S1C, D) and extreme morphologies of the FF not observed in any other eremobatid genus, such as sigmoidal shapes, modified folded tips, or FF in a positive slope position with respect to the manus. Pedipalpal tarsi possess a high density of setae. Legs are also slim and long (e.g. Fig. 3B).

Note on spine-like setae

Chanbria brookharti (Fig. 8) and C. mapemes (Fig 9) are the first observed Chanbria species known to have enlarged,moveable palpal spines. Similar palpal spines have been found in other eremobatids and is a current synapomorphy for the genus Horribates Muma, 1962 (Muma, 1989). In eremobatids, such spines are motile, having a ~45° range of movement between their extended state perpendicular to the pedipalp and their relaxed state. Histological cross-sections of such spines indicate that haemolymph pressure might be responsible for extending and retracting these spines in a hydraulic fashion.Likewise, the presence of pores at the tip of these specialized spines that open into the subcutaneous tissue suggests a sensory function (Garcia EL, Laudier D, Cushing PE, unpublished data). In some eremobatid specimens that possess these spines, a notched base is present which allows the spines to be ‘locked’ in an extended position. Similar moveable spines are also present on the appendages of other solifuge families (WGarcia EL, pers. obs.) and arachnid groups, such as in the lycosid spider Zoropsis spinimana (Dufour, 1820), which uses these spines to aid in subduing prey during capture (Eggs et al. 2015). Eremobatid solifuges have been observed capturing and manipulating prey with their pedipalps (Willemart et al. 2011), hence the palpal spines of C. brookharti, C. mapemes, and other eremobatids that possess these structures might play a similar role in subduing prey.