Eremocosta gigas 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 : 456-457

Eremocosta gigas Roewer 1934

Figs. 1D , 2K–N , 3D , 4C , 5D & E

Eremocosta gigas Roewer 1932 (nomen nudum): figs. 127a–b. Eremopus gigas ( Roewer 1934) : Muma 1989: 5.

Not Eremorhax gigas ( Roewer 1934) : Muma 1951 (misidentified): 48, figs. 32–33. Eremocosta gigas ( Roewer 1934) : Harvey 2002: 451.

Type material. Male holotype from Tampico, México (SMF). Muma’s 1951 designation was in error and was in fact the description of E. gigasella which he corrected in 1970 and added the description of E. gigas at that time. We were able to examine the type.

Other specimen examined. Female (1). (Previously undescribed.) MÉXICO: Durango, Dinamita, N 25.733333°, W 103.666667°, 1328 m elev., 29 July 2005, coll. O. Francke, H. Montaño, J. Ballesteros, C. Durán- Barrón, at night ( IBUNAM +CNAN-Sol00114).

Diagnosis. Eremocosta gigas male is distinguished by its unique cheliceral shape with a sharp dagger-like fixed finger, a long thin fondal notch, and the presence of an acute distal tooth (MD) on the movable finger ( Fig. 2K , arrow). The female genital operculum is also distinct with tear-drop shaped opercular wings that diverge distally ( Fig. 4C ).

Measurements. Holotype Male. TL 50.0; CL 10.4; CH 7.7; FNL 1.3; FNH 1.0; FFH 2.2; PL 47.0; PMT NA; PT 2.6; PMT 10.3; LI damaged; LIV 50.3; PPL 8.0; A/CP NA; FNL/FNH 1.3,; FFH/FNH 2.2.

Female. TL 47.0; CL 14.0; CH 6.4; PPL 5.7 ; PL 39.5; PT 2.6; PMT 8.6; LI 28.5 ; LIV 40.5; A/CP 5.5.

Description. Coloration. Male. Overall pale yellow body and appendages. Propeltidium lightly mottled brownish-violet, darker on the anterior margin ( Fig. 5D ). Abdomen dusky.

Chelicera. Male. Typical ventrally located VDC with a thin carina inside the cavity ( Fig. 1D , arrow) similar to E. striata and E. gigasella ( Figs. 1E & F ). Fixed finger with no median dentition. Movable finger: prominent MPone tiny MSM-small MM-small MD (the only Eremocosta to possess a distinct tooth-like MD); MPL prominent ( Figs. 2K & L ; tip of MPL tooth just visible in front of MP in Fig. 2L ). Fondal notch distinct, narrow and rounded, greater than height; height of fixed finger larger than height of fondal notch ( Fig. 2K ). One very tiny RFA in fondal notch and one tiny RFA on ventral side of fixed finger; fondal teeth retrolaterally II, I, III, tiny IV; prolaterally I, III, II, IV ( Fig. 3D ).

Setation. Male. Cheliceral setal pattern, pvd setae typical; mvd a proximal patch of plumose setae. Typical setation of pedipalps. A few scattered bacilli on the coxae of LII and LIII. No scopula or ctenidia.

Coloration. Female. Basically cream-yellow, legs similar but a bit darker. Palp dusky on tarsus and metatarsus, LIV light violet at tibia-femur joint; propeltidium blotchy violet-brown, darker on anterior edge, creamy oval area behind ocular tubercle and smaller ovals on either side ( Fig. 5E ). Abdomen with typical dark, violet brown rectangles on each segment that give the appearance of a stripe; ventral grey-cream.

Chelicera. Female. Chelicera worn but apparently fixed finger: FP-2FSM-FM-FSD-FD. Movable finger: MP (very worn)-MSM if present, worn away-MM ( Figs. 2M & N ). MPL apparently missing but may just be worn away. One large RFA; fondal teeth I, III, II, IV (III almost the same size as I) retrolaterally and prolaterally.

Setation. Female. Typical with inner row of plumose bristle extending from FM on fixed finger to MM on movable finger. A row of thick bacilli on anterior edge of LIII coxa and a row of smaller bacilli on anterior edge LIV coxa.

Genital Operculum. Genital operculum tear-drop shaped with slender anterior arms, posterior wing rounded with inner edge slightly notched posteriorly. No visible pits laterally ( Fig. 4C ).

Distribution. MÉXICO: Veracruz. Biome: Chihuahuan Desert.

Discussion. We place the female from Dinamita, Durango, México in this species because of the overall similarity in body size and color pattern. However, without females collected from the type locality and without males collected from the new site we may find this placement either refuted or supported as more specimens are examined from México.

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).

FIGURE 5. Propeltidia of specimens illustrated in Fig. 2. Scale bars = 1.0 mm. A) Eremocosta bajaensis male (holotype from CAS). B) Eremocosta calexicensis male (holotype from USNM). C) Eremocosta formidabilis male (IBUNAM). D) Eremocosta gigas male (holotype from SMK). E) Eremocosta gigas female (IBUNAM CNAN Sol00114). F) Eremocosta gigasella male (DMNS ZA.35465). G) Eremocosta striata male (DMNS ZA.21079). H) Eremocosta titania male (DMNS ZA.15427).