Eremocosta Roewer 1934

Cushing, Paula E., Channiago, Felix & Brookhart, Jack O., 2018, Revision of the camel spider genus Eremocosta Roewer and a description of the female Eremocosta gigas Roewer (Arachnida, Solifugae), Zootaxa 4402 (3), pp. 443-466 : 445-446

Genus Eremocosta Roewer 1934 .

Eremopus Roewer 1934: 561 [Junior homonym of Eremopus Brady 1910 (Crustacea, Copepoda)], Muma 1989: 4. Eremocosta Roewer 1934: 569 (synonymized by Muma 1951: 41).

Eremocantha Roewer 1934: 571 (synonymized by Muma 1970: 9).

Type species. Of Eremopus : Eremopus montezuma Roewer 1934 , by original designation. Of Eremocosta : Eremocosta gigas Roewer 1934 , by original designation. Of Eremocantha: Eremocantha robusta Roewer 1934 , by original designation.

Revised diagnosis. Eremocosta species are relatively large; ranging from 26 to 50 mm in length. Color patterns of the body and pedipalps are variable. The diagnostic synapomorphy of Eremocosta is the male fixed finger with a deep VDC ( Figs. 1A–G ). Neither Roewer (1934) nor Muma (1951, 1970) described the carina running inside this cavity that is evident in some species ( Figs. 1B–F , arrows). The fixed finger of males lacks median dentition ( Fig. 2 ). The movable finger of males has a large MP, one to two MSM, and one MM teeth ( Fig. 2 ). The MP tooth is large and distinct. In E. gigas , E. gigasella , and E. striata the movable finger has what we here call a distal tooth of the movable finger (MD) ( Figs. 2K, O & S , arrows). The fondal notch ranges from obscure to distinct ( Fig. 2 ), and ordinarily has two to four RFA in the fondal notch and in some species one to three RFA on the ventral side of the fixed finger ( Fig. 3 ). Pro- and retrolateral fondal teeth vary in gradation among the species ( Fig. 3 ). The retrolateral IV is tiny in some species. Male cheliceral setal formation (sfc) consists of tubular setae dorsally, two rows of tubular setae prolaterally with the inner mesal row being plumose and extending dorsally to and sometimes above fondal tooth I. The prodorsal setae (mpd) consist of a proximal patch in all species except E. gigasella which has a linear row extending to MM. The proventral distal setae (pdp) consist of three robust setae and one proximal thin seta. The female chelicera fixed finger has a large FP, one to two FSM, a large FM, small FSD, and distinct FD ( Fig. 2 ). The female movable finger has a large MP, one or two MSM, and one MM teeth. MPL tooth distinct on males and females ( Fig. 2 ). Eremocosta females demonstrate typical eremobatid female cheliceral setal pattern with pvd and mpd setae forming a continuous plumose row from the FD to the MM teeth. The arms of the genital operculum of Eremocosta are alate and widely separated posteriorly ( Fig. 4 and Muma 1989). The genital operculum is largely species-specific with some possessing thin arms with club like wings; others recurved, bent laterally at their posterior ends with no distinct external pits. No palpal papillae or ctenidia are present.

Figures

FIGURE 1. VDC on the fixed finger of the right chelicera of male Eremocosta. Refer to Figure 2 for scale. A) Eremocosta bajaensis (holotype from CAS).B) Eremocosta calexicensis (holotype from USNM).C) Eremocosta formidabilis (IBUNAM). Note the more proximal locationof the VDC on the fixed finger of thisspecies.D) Eremocosta gigas (holotype from SMK).E) Eremocosta gigasella (DMNS ZA.35465). F) Eremocosta striata (DMNS ZA.21079). G) Eremocosta titania (DMNS ZA.15427).Arrows point to an internal carina in the VDC of some species.

FIGURE 2. Retrolateral (left) and prolateral (right) cheliceral views of the right chelicera of Eremocosta species. Scale bars = 1.0 mm. See text for collection abbreviations. A & B) Eremocosta bajaensis male (holotype from CAS). C & D) Eremocosta bajaensis female (IBUNAM). E & F) Eremocosta calexicensis male (holotype from USNM). G & H) Eremocosta calexicensis female (allotype from USNM). I & J) Eremocosta formidabilis male (IBUNAM). K & L) Eremocosta gigas male (holotype from SMK). M & N) Eremocosta gigas female (IBUNAM CNAN Sol00114). O &P) Eremocosta gigasella male (DMNS ZA.35465). Q & R) Eremocosta gigasella female (DMNS ZA.17350). S & T) Eremocosta striata male (DMNS ZA.21079). U & V) Eremocosta striata female (DMNS ZA.25451). W & X) Eremocosta titania male (DMNS ZA.15427). Y & Z) Eremocosta titania female (DMNS ZA.36256).Arrows in K, O, and S point to MD tooth (see text).

FIGURE 3. Fondal teeth on right fixed fingers of male specimens illustrated in Fig. 2. See Fig. 2 for scale. A) Eremocosta bajaensis (holotype from CAS).B) Eremocosta calexicensis (holotype from USNM).C) Eremocosta formidabilis (IBUNAM). D) Eremocosta gigas holotype from SMK). E) Eremocosta gigasella (DMNS ZA.35465). F) Eremocosta striata (DMNS ZA.21079).G) Eremocosta titania (DMNS ZA.15427).

FIGURE 4. Genital opercula of females. Same specimens as illustrated in Fig. 2. Scale bars = 1.0 mm. A) Eremocosta bajaensis(IBUNAM).B) Eremocostacalexicensis (allotypefrom USNM).C) Eremocosta gigas (IBUNAM CNANSol00114). D) Eremocosta gigasella (DMNS ZA.17350). E) Eremocosta striata (DMNS ZA.25451). F) Eremocosta titania (DMNS ZA.36256).