Eremocosta gigasella ( Muma 1970 )

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 : 457-458

Eremocosta gigasella ( Muma 1970)

Figs. 1E , 2O–R , 3E , 4D , 5F

Eremorhax gigas ( Roewer 1934) : Muma 1951 (misidentification): 48, figs. 32–33. Eremorhax gigasella Muma 1970: 8 .

Eremopus gigasella ( Muma 1989) : 5.

Eremocosta gigasella ( Muma 1970) : Harvey 2002: 451.

Type material. Male holotype from Boquillas, Texas, USA, 7 June 1948, coll. C. and P. Vaurie ( AMNH). We were able to examine the type.

Other specimens examined. Males (8). MÉXICO: Coahuila, Sierra San Marcos II, Cuatro Ciénegas, N 26.91326°, W 102.13757°, 761 m elev., no date, coll. E. González-S., B. Hendrixson, K. McWest, S. Grant , collected with UV. light ( IBUNAM +CNAN-Sol100007) ; MÉXICO : Coahuila, Saltillo , 27 May 1967, coll. M. Oyervides, no other data ( IBUNAM +CNAN-Sol00204) ; USA: New Mexico, Eddy County, Carlsbad , N 32.45°, W 104.30°, 1012 m elev., 10 June 1940, coll. E.S. Deevey, on tent ( DMNS ZA.17982) ; USA: Texas, Brewster County, Big Bend National Park, south of Camp De Leon turn-off, east side of Old Ore Rd. , N 29.245°, W 103.01167°, 696 m elev., 11 June–8 July 2011, coll. David Footle, pitfall trap (3 males: DMNS ZA.35465) ; USA: Texas, Brewster County, Big Bend National Park, east of Terlingua Abajo Village sign, N 29.1975°, W 103.60194°, 673 m elev., 11 June –8 July 2011, coll. David Footle, pitfall trap in sandy flood plain behind Acacia thicket (2 males: DMNS ZA.35475).

Females (7). MÉXICO: Coahuila, Sierra San Marcos II, Cuatro Ciénegas , N 26.91326°, W 102.13757°, no date, coll. E. González-S., B. Hendrixson, K. McWest, S. Grant, collected with UV light; (2 females: IBUNAM +CNAN-Sol100007; USA: Texas, Brewster County, Big Bend National Park, south of Camp De Leon turn-off, east side of Old Ore Rd. , N 29.245°, W 103.01167°, 696 m elev., 11 June–8 July 2011, coll. David Footle, pitfall trap (3 females: DMNS ZA.35465) ; USA: Texas, Brewster County, Big Bend National Park, east of Terlingua Abajo Village sign, N 29.1975°, W 103.60194°, 673 m elev., 11 June–8 July 2011, coll. David Footle, pitfall trap in sandy flood plain behind Acacia thicket (2 females: DMNS ZA.35475).

Diagnosis. Eremocosta gigasella is distinguished by the lack of a fondal notch on the male fixed finger ( Figs. 2O & P ). All other species in the genus have a moderate fondal notch to distinct fondal notch. On the male fixed finger, the relatively flattened MM is also distinctive as well as the presence of an apparent MD or a tooth-like structure at the distal location of the movable finger (Fig. 20, arrow). The female genital operculum is similar to that of E. titania ; however, the two species can be easily distinguished with the posterior part of arms of E. gigasella more rounded and the inner edge slightly hooked (compare Figs. 4D & F ).

Measurements. Males (n = 8). TL 28.0–42.0; CL 9.5–14.0; CH 4.0–6.0; FNL NA; FNH 0.5; FFH 1.0–1.3; PL 29.5–40.5; PT 1.7–4.0; PMT 5.4–9.0; PT 3.0–4.5; LI 20.0–28.0; LIV 33.0–43.0; PPL 35.0–43.0; A/CP 4.7–5.5; FNL/FNH NA; FFH/FNH NA; FFH/ CH 0.2–0.3.

Females (n = 7). TL 39.0–50.0; CL 10.7–16.0; CH 4.3–6.0; PL 29.0–35.0; PT 1.7–3.5; PMT 7.0–7.9; LI 20.5– 30.0; LIV 31.0–45.0; A/CP 4.6–5.0.

Description. Coloration. Male. Palpal tarsus, metatarsus faintly dusky violet-brown; LI, LII pale; LIII, LIV dusky violet-brown at the tibia-femur joint. Propeltidium mottled brownish violet anteriorly with a large pale yellow oval behind ocular tubercle, two smaller pale yellow ovals on either side of ocular tubercle ( Fig. 5F ). Abdomen dark dorsally, greyish ventrally.

Chelicera. Male. VDC occupies approximately half the length of fixed finger; deep, with a thin carina on the interior extending half the length of the cavity ( Fig. 1E , arrow). Fixed finger broad proximally, sinuate dorsally with no median dentition. Movable finger: large MP-2 MSM the proximal larger-MM a long ridge with notch in the middle; MD also a ridge; MPL distinct ( Figs. 2O & P ). Fondal notch indistinct. Two distinct RFA in the notch and two tiny RFA on ventral edge of fixed finger; fondal teeth graded retrolaterally I & II (equal), III, tiny IV; prolaterally I, III, IV, tiny IV ( Fig. 3E ).

Setation. Male. Apical setal complex flat and plumose. No ventral series. Inner medial setal complex plumose setae to the top of fondal notch; mpd extend to the front of MM. This is the only Eremocosta that has a linear mpd as opposed to patchy configuration. Pedipalps with scattered long thin setae. No ctenidia. No palpal papillae. Scattered bacilli on anterior part of coxa of Leg 3.

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

Chelicera. Female. Fixed finger: FP-2 FSM-FM-FSD-FD. Movable finger: MP-2 MSM–MM; large MPL ( Figs. 2Q & R ). One large RFA; fondal teeth I, III, II, IV (III almost the same size as I) retrolaterally and prolaterally.

Setation. Female. Inner row of plumose bristle typical, extend from FD on fixed finger to MD on movable finger. A row of thick bacilli on anterior edge of LIII coxa and a row of smaller bacilli on edge LIV coxa.

Genital Operculum. Genital operculum club shaped with slender anterior arms, posterior rounded with inner edge slightly hooked posteriorly. No visible pits laterally. Genital operculum not as in fig. 31 in Muma (1951). More like E. titania fig. 38 in Muma (1951) but with wider, shorter anterior arms and larger more rounded club shape posteriorly ( Fig. 4D ).

Distribution. USA: New Mexico, Texas and México. Biome: Chihuahuan Desert.

Discussion. This species was described by Muma (1951) as E. gigas . This species is a Chihuahuan Desert inhabitant extending from New Mexico ( Brookhart & Brantley 2000) into the Big Bend region of Texas and south into the Mexican states of Chihuahua, and Coahuila. The collection of this species by David Footle (personal comm.) from 20 pitfall arrays in Big Bend National Park resulted in 24 males, 24 females from April to August. They were collected in 5 of the 20 arrays set up by the collector in the park. Brookhart & Brantley (2000) identified this species as far north and west as Socorro, New Mexico, USA.

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).