Type Material

            Holotype: "Male holotype, female allotype and male paratypes from Calexico, California, USA, coll. M.G. Armstrong, no date (USNM 2073704)" (Cushing et al., 2018).

            Measurements: Male holotype: TL 37.0; CL 10.4; CH 4.0; FNL 0.3; FNH 0.5; FFH 1.0; PL 42; PT and PMT NA (pedipalps of male disassociated in vial and damaged); LI 31.0; LIV 56.0; PPL 5.2; A/CP 8.3; FNL/FNH 0.6; FFH/FNH 2.0.

Female allotype: TL 42.0; CL 13.8; CH 6.1; PL 41.0; PT and PMT NA (pedipalps of female disassociated in vial and damaged); LI 30.0; LIV 49.0; A/CP 6.1.

            Chelicera Description: Male: "Chelicera as in Muma (1951, p. 49, fig. 40). VDC deep, cup-shaped occupying approximately one-third to one-half the length of fixed finger with a slight prolateral orientation (Fig. 1B). Fixed finger with no median dentition. Movable finger: large, acute MP-small MSM-small MM; large MPL. (Figs. 2E & F). Fondal notch tiny. Sometimes 1–3 RFA on the ventral edge of the fixed finger as well as 2–3 in the fondal notch (Fig. 3B). Muma graded the fondal teeth I, II, III, IV but we suggest they might be II, I, III, IV since I and II are about equal in size, tiny or absent IV retrolaterally and I, III, II, tiny serrate IV prolaterally (Fig. 3B). FNH smaller than the FFH" (Cushing et al., 2018).

Female: ":Typical. Fixed finger: FP-FSM-FM-small FSD-FD. Movable finger: MP-MSM-MM; MPL distinct (Figs. 2G & H). One large RFA; fondal teeth II, III, I, tiny IV retrolaterally; I, III, II, IV prolaterally" (Cushing et al., 2018).

            Genital Operculum: "Female genital operculum as in Muma (1951, fig. 43) with long anterior arms, club-like wings with two tiny outgrowths/knobs on the interior margin (Fig. 4B)" (Cushing et al., 2018).

Diagnosis: "Eremocosta calexicensis is closely related to E. titania. The two species can be separated by the length of the fixed finger of the male, shape of the VDC, and relative length of the VDC. Most males of E. calexicensis have the fixed finger somewhat shorter than the movable finger. The edge of the VDC, when viewed from the retrolateral surface (Fig. 2E) is slightly convex compared to the same view of the VDC of E. titania. The VDC of E. calexicensis also extends only 1⁄2 or less the length of the fixed finger whereas the VDC of E. titania typically extends more than 1⁄2 the length of the fixed finger (compare Fig. 2E & W). Males of E. calexicensis are also generally larger than males of E. titania. The female genital operculum is also distinct from E. titania. The wings of the genital operculum of E. calexicensis are shaped like hockey sticks with the inner margins more or less parallel to one another (Fig. 4B), whereas the inner margins of the wings quickly diverge in E. titania (Fig. 4F)" (Cushing et al., 2018).

Other Information: "Because of the morphological similarity between E. calexicensis and E. titania and because the ranges are partly sympatric, there may be instances of hybridization between the two species. Cushing et al. (2015) demonstrated no significant molecular differences between the two specimens used to represent E. calexicensis and E. titania in the phylogenetic analysis. Upon re-examination of these specimens, it was clear that they both represented E. titania. Muma’s (1951) designation of specimens from Arizona are probably E. striatus and those from coastal California are probably E. bajaensis. In his 1951 descriptions of both E. calexicensis and E. titania Muma noted variance that probably reflects these misidentifications" (Cushing et al., 2018).

Users of this Field Guide, be aware that iNaturalist images and associated “species identifications” are NOT verified by voucher specimens and not reviewed by solifuge researchers. Therefore, do not use iNaturalist images for identification purposes.