Type Material

            Holotype: “Male type from Guanajuata, México, No. 1805 (Roewer No. 9130), deposited in Muséum National d’Histoire Naturelle, Paris, France. The female and young with the type are not conspecific (Muma 1970). Muma’s examination of types found a female paratype labeled “Arkansas” in Zoologisches Staatsinstitut und Zoologisches Museum in Hamburg, Germany he thought to be conspecific. The locality is apparently incorrect. If it refers to a locality in the United States then it is unlikely to be the female of E. formidabilis. The female chelicera is illustrated as fig. 2, p. 13 in Muma (1970) but no description is provided (see Muma 1970, p. 16). It is not a typical Eremocostafemale dentition. We were not able to examine the type of E. formidabilis but were able to examine males of this species from localities near the type locality: male from San Luis Potosi, México (Texas Tech University) and a male from Durango, México and San Luis Potosi, México (IBUNAM)” (Cushing et al., 2018, p. 455-456)

            Measurements: “(n = 2). TL 22.0, 30.0; CL 6.6, 10.0; CH 2.8, 4.7; FNL 0.3, 0.5; FNH 0.3, 0.5; FFH 0.8, 1.3; PL 17.0, 23.0; PT 1.4, 2.7; PMT 5.7, 11.5; LI 11.0, 13.0; LIV 16.5, 16.5; PPL 4.0, 4.3; A/CP 4.2; FNL/FNH 1.0, 1.0; FFH/FNH 2.8, 2.8; FFH/CH 0.3, 0.3” (Cushing et al., 2018, p. 456).

            Palpal Description: “Pedipalps with scattered, long, thin setae, and shorter, thicker setae. Palpal tibia with a series of strong setae basally on the mesal surface. No visible paired setae” (Cushing et al., 2018, p. 456).

            Chelicerae Description: “Chelicera as in Muma (1970, p. 13, fig. 1-2). VDC proximally located (Fig. 1C). Neither Roewer (1934) nor Muma (1970) mentioned or illustrated this unique position of the VDC. Fixed finger with no median dentition. Movable finger: large MP-three MSM attached to MP; distinct MPL (Figs. 2I & J). Fondal notch narrow, longer than wide (Fig. 2I). Two tiny RFA; fondal teeth I, III, II, IV prolaterally and retrolaterally (Fig. 3C)” (Cushing et al., 2018, p. 456).

Diagnosis: “E. formidabilis is easily distinguished from all other Eremocosta by the location of the VDC which lies proximally instead of distally on the ventral edge of the male fixed finger (Fig. 1C). It is also smaller than others and the dark tips of the pedipalps are also distinctive” (Cushing et al., 2018, p. 456).

Other Information: “Putnam’s (1883), Roewer’s (1934), and Muma’s (1970) descriptions are adequate. Two tiny RFA in fondal notch (Fig. 3C). Roewer (1934) indicates 4 ctenidia but Muma (1970), in examining the type, found no ctenidia. The two males that we examined had no ctenidia” (Cushing et al., 2018, p. 456).