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PHYLOGENY/TAXONOMY
EREMOBATINAE
Eremobates angustus group aztecus group lapazi group pallipes group palpisetulosus group scaber group Eremobates actenidia Eremobates clarus Eremobates corpink Eremobates ctenidiellus Eremobates hodai Eremobates icenogelei Eremobates legalis Eremobates mormonus Eremobates scaber Eremobates similis Eremobates socal Eremobates zinni vallis group Eremocosta Eremorhax Eremothera Horribates THEROBATINAE Chanbria Eremochelis Hemerotrecha
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Eremobates scaber species group
Diagnosis: Muma (1951) established this group to accommodate species of Eremobates that he characterized as having.a wide basal notch in the fixed cheliceral finger of males that is visible from dorsal view. He described the notch as occupying one-third or more of the length of the finger. The mesoventral groove of the fixed finger, he stated, is dilated basally, and the first postspiracular abdominal sternite is provided with two to six ctenidia. Females, he reported, have roughly triangular genital opercula that are well separated along most of their mesal margins. Although he reported that both rows of fondal teeth are graded I, III, II, IV in size, he later (Muma 1986, 1987) suggested that fondal tooth formulae are not valid for genus or group separation, as they are subject to wear, especially by females. TYPICAL SPECIES: Eremobates scabernm(Kraepelin). Muma 1970
Mesal groove of fixed cheliceral finger mesoventral in
position Mesal groove narrow apically, occupying less than half of finger
width Mesal groove distinctly dilated basally Brookhart and Cushing 2004 In the scaber group the mesoventral groove is deep and narrow. The female genital opercula are roughly triangular with species distinguished by differences in the medial margins. Muma (1951) listed six species in the scaber group including the typical or defining species E. scaber (Kraepelin 1899) although he had not seen the female type specimen. After examining type specimens in both the U.S. and Europe as well as other specimens from various collections and collectors Muma (1970) recalled Kraepelin’s 1899 description of Datames scaber based on the female type from ‘‘Washington Territory’’ as the correct characterization of Eremobates scaber. He used his 1951 description, erroneously attributed to E. scaber, to establish E. septentrionis Muma 1970, used his 1951 description of E. geniculatus to erect E. mormonus (Roewer 1934) and defined E. geniculatus (C.L. Koch 1842) (Simon 1879, misidentified) using Simon’s 1879 description of a single female from Mexico (Muma 1970). In 1989 Muma described six new species. This resulted in 15 species in the scaber group with E. scaber, E. actenidia Muma 1988, E. clarus Muma 1989, E. consors Muma 1989, E. ascopulatus Muma 1951 and E. hodai Muma 1989 described from only one sex although Muma included the male of E. scaber in the key. Eremobates clarus, E. actenidia and E. consors were each described from a single specimen and E. ascopulatus from two males. Eremobates similis (Muma 1951) was noted as being described in both sexes (Muma 1989), but the female description has not been found. In describing E. scaber, Muma (1951) used specimens from an area that extended from the northwestern United States to Las Vegas, Nevada but noted that it might include other species of this group. In addition, other species of this group seemed to have sympatric ranges (Muma 1951, 1962, 1989). In each of his publications Muma (1951, 1962, 1989) cited several problems with the distinction between species and problems of sympatric associations. Muma (pers. comm.) indicated that this group needed to be more thoroughly studied. For the most part, this group is an inhabitant of pinon pine-juniper or desert shrub communities. Muma (1963) identified E. zinni (Muma 1951), E. similis, E. ctenidiellus and E. mormonus as inhabitants of the Mercury, Nevada Nuclear Test Site, a Mojave Desert region, although some of the specimens were misidentified. Allred & Muma (1971) listed E. septentrionis and E. ctenidiellus as inhabitants of the Snake River Plain which is part of the Columbian Plateau. Brookhart (1972) found E. mormonus, later changed to E. similis, in the San Luis Valley of Colorado and E. ctenidiellus in the mesa regions of western Colorado. The Sevilleta Long Term Ecological Reserve project at the northern tip of the Chihuahuan Desert surveyed six distinct desert grassland/high desert areas and found E. similis in only the pinon-juniper association (Brookhart & Brantely 2000). At the Hanford Nuclear Site, Rich Zack’s E. scaber material (WSU) was collected in Great Basin Desert shrub habitat, and various Canadian specimens were collected in the sagebrush of the Okanogon Valley. Eremobates scaber group species have been collected at 2394 m in Wyoming, 2303 m in the San Luis Valley of Colorado, and on Mt. Palomar, California. Muma (1951, 1962, 1970, 1989) used length vs. width of the fondal notch, number and shape of ctenidia, and number of palpal papillae, as well as coloration of appendages to separate each species. The number of ctenidia ranged from 0–6. The palpal scopula varied from none to over 120 papillae. Females were identified by the structure of the genital operculum and the coloration of appendages. Coloration of eye tubercle and malleoli were noted but were consistently the same for all species with eye tubercles dark and malleoli white. Abdominal coloration varied from a pale yellow to a grey background dorsally and ventrally with lighter pleural membranes between species and also between specimens of the same species. Many specimens had tergites with a rectangular, brownish, violet pigmentation which gave the appearance of a broad stripe to many specimens. Muma (1951) calls this a sclerite although it is not particularly thick or hardened. It was not found to be diagnostic in this study. Male chelicerae have no teeth on the fixed finger and some variation in the shape of the fixed finger in ectal view. The movable finger follows the general pattern of a large primary tooth, two intermediate teeth, the posterior being larger and an anterior tooth. The mesal tooth varies from tiny to absent. Female chelicerae have a fixed finger with teeth ordered successively posterior to anterior, intermediate tooth, large primary tooth, two intermediate teeth, medial tooth, a single intermediate tooth and a smaller anterior tooth. The female movable finger has a large primary tooth, a variable sized anterior tooth and two intermediate teeth, the posterior of which is larger. The mesal tooth varies from absent to medium size. Fondal teeth in both male and female grade out I, III, II, IV in size, although in some species the fondal tooth III is equal in size to fondal tooth I. Due to wear, the intermediate teeth on both male and female movable fingers are sometimes hard to diagnose. Distribution:
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