Spiders of the Chihuahuan Desert of southern New Mexico and western Texas.
Although >80% of the Chihuahuan Desert occurs in Mexico (Ricketts et al., 1999), the 20% that occurs in the United States encompasses a variety of habitats. These include desert with creosotebushes (Larrea tridentata), dunes with mesquites (Prosopis), mountain slopes, mountains, grasslands, playa lakes, riparian areas and washes, pure sand dunes, and rocky outcrops. The northern one-third of the Chihuahuan Desert is the Trans-Pecos subregion and covers parts of northern Mexico, southern New Mexico, and western Texas (Ricketts et al., 1999). Over this area, there have been ecological or biogeographical studies that have included arachnids such as scorpions (Shelley and Sissom, 1995), solifugids (Muma, 1979; Brookhart and Brantley, 2000), harvestmen (Mackay et al., 1992), and mites (Cepeda-Pizarro and Whitford, 1989), but only a few have focused on spiders (Muma, 1975; Gertsch and Riechert, 1976; Broussard and Horner, 2006; Lightfoot et al., 2008).
Over the past 30 years, we collected spiders in different habitats within the Chihuahuan Desert on the Jornada del Muerto of southern New Mexico and have compiled a list of species from museum holdings at New Mexico State University and the University of New Mexico. Goals of our research were to describe the spider fauna, to compare our list of species to those of previous researchers in the area (Muma, 1975; Gertsch and Riechert, 1976; Broussard and Horner, 2006), and to assess habitat and seasonal associations of species in the Chihuahuan Desert of the United States.
MATERIALS AND METHODS--The southern portion of the Jornada del Muerto, Dona Ana County, New Mexico, is an Experimental Range of the United States Department of Agriculture and the Chihuahuan Desert Rangeland Research Center of New Mexico State University. It is east of the Rio Grande and between the San Andres Mountains to the east and the Dona Ana Mountains to the west and south. Although altered by drought, grazing by cattle, and activity of humans to the present form of mostly brushland over the past 150 years (Buffington and Herbel, 1965; Hennessey et al., 1983), the Jornada del Muerto is a mosaic of black grama-mesa dropseed (Bouteloua eriopoda-Sporobolus flexuosus) grassland, tobosa (Hilaria mutica) grassland, dunes with mesquites (Prosopis), creosotebush (Larrea tridentata) and tarbush (Flourensia cernua) desert, scattered yuccas (Yucca), and playa lakes, with mountain slopes along the Dona Ana and San Andres mountains.
Spiders were collected primarily by pitfall traps, along with hand collecting and sweep netting. Spiders were collected from numerous sites during 30 years, including areas dominated by mesquites, tarbushes, creosotebushes, grasslands, mountain slopes, and playas. During 13 months (1978-1979), 40 pitfall traps were used (20 at each site) north of West Well (32[degrees]36'18"N, 106[degrees]50'51"W) on the Jornada del Muerto and sampled, usually, every 2 weeks (Richman et al., 1982). While this study concentrated mostly on a comparison of tenebrionid beetles between 2,4,5-T-sprayed sites and controls for studies of mesquite herbicides, all salvageable spiders were preserved as specimens. During 1992-2002, samples of spiders in pitfall traps have been collected continuously at the Long Term Ecological Research site on the Chihuahuan Desert Rangeland Research Center of New Mexico State University (ca. 32[degrees]30'N, 106[degrees]48'W, 1,188 m elevation).
Pitfall traps and searching were used to sample spiders on the Jornada del Muerto during two other studies. In the first, spiders were sampled and captured alive in pitfall traps from 15 plots (5 by 5-m plots) and 14 marked shrubs (six mesquites, four creosotebushes, and four tarbushs) during October-November 1999 and April-May 2000. These sites included 3 plots on dunes with mesquites between West Well and the Headquarters (32[degrees]36'57"N, 106[degrees]44'32"W) and 12 sites near South Well (32[degrees]32'00"N, 106[degrees]44'50"W). A total of 967 spiders was collected, 557 in October-November and 410 in April-May (M. E. A. Whitehouse, in litt.). The second study used similar methods on 30 plots, but was centered on both the Chihuahuan Desert Rangeland Research Center of New Mexico State University near the Long Term Ecological Research site and the Jornada Experimental Range near South Well. Spiders were sampled during October-December 2000 and April-June 2001. A total of 1,795 spiders was collected, 861 in spring and 934 in autumn (Hu, 2002). Finally, other samples have been collected since the 1970s on other trips to the Jornada del Muerto, mostly by sweep netting and searching, including collections made at Red Lake Well (32[degrees]42'32"N, 106[degrees]49'28"W), at a playa lake just south of the Jornada Experimental Range, and in the foothills of the Dona Ana Mountains. The resultant list is based on a total of .10,000 specimens.
White Sands National Monument, Otero County, New Mexico, is an area of gypsum (calcium sulfate) dunes and surrounding rangeland ca. 50 km northeast of the Jornada del Muerto. Muma (1975) used pitfall traps to sample in the dunes and in an area 10 km north of the monument near Alamogordo, Otero County, New Mexico, during June-September 1972. Valley of Fires near Carrizozo, Lincoln County, New Mexico, sampled by Gertsch and Riechert (1976), is ca. 170 km northeast of the Jornada del Muerto. They sampled on the lava and on adjacent grassland during 1969-1974. Methods included pitfall traps, sweep netting, suction sampling, and beating. While this site is just outside the Chihuahuan Desert, exact boundaries of this desert are not that distinct and the Valley of Fires and adjacent area is similar to much of the Jornada del Muerto.
Sites in western Texas (Broussard and Horner, 2006) were near Big Bend National Park, Presidio County, ca. 500 km southeast of the Jornada del Muerto and were areas of desert pavement and a dry stream bed. Spiders were collected in 1999-2000 using pitfall traps. Because sampling effort among studies was unequal in methods, time, and area, we did not make statistical comparisons.
We identified spiders from the Jornada del Muerto using Ubick et al. (2005) and verfied names using N. I. Platnick (http://research.amnh.org/entomology/spiders/catalog/INTRO1.html). Specimens were deposited in the Arthropod Museum, New Mexico State University, Las Cruces, the Museum of Southwestern Biology, University of New Mexico, Albuquerque, and the Florida State Collection of Arthropods, Gainesville.
RESULTS--The spider fauna on Jornada del Muerto included 117 species in 24 families; [greater than or equal to] 5 were undescribed species (Table 1) and [greater than or equal to] 4 were range extensions. Potential undescribed species occurred in three families (Gnaphosidae, Salticidae, and Thomisidae), which are large and still not completely known in the Southwest. A sixth possibly undescribed species was in the genus Filistatoides (Filistatidae). N. I. Platnick (http://research.amnh.org/entomology/spiders/catalog/INTRO1.html) did not mention any species in this genus from the United States, although Ubick (2005) listed F. insignis and two undescribed species mentioned by Roth (1994). Thus, we are uncertain as to status of these specimens. Range extensions on the Jornada del Muerto were four state records: Phidippus californicus (Salticidae) was known previously from Baja California, northern Mexico, Arizona, California, Nevada, Oregon, Texas, and Utah (Edwards, 2004); Syspira analytica (Miturgidae) was known previously from Baja California and western Arizona (Chamberlin, 1924); Habronattus icenoglei (Salticidae) was known previously from as far east as Maricopa County, Arizona (Griswold, 1987; and Ebo macyi (Philodromidae) was known previously from as far east as Portal, Cochise County, Arizona (Sauer and Platnick, 1972).
Some species were strongly associated with a given habitat, plant, or substrate. Synageles noxiosus, an ant-like salticid, was common on woody snakeweeds (two species of Gutierrezia; D. B. Richman and D. C. Thompson, in litt.), Sassacus papenhoei, a beetle-like salticid with metallic scales, was often on creosotebushes, and Herpyllus bubulcus was collected commonly on the ground from creosotebush habitat. Diguetia signata was only in tarbushes, while D. canities was common in creosotebushes. Geolycosa rafaelena, a wolf spider, was almost always inside silk-lined burrows in sandy soils and Physocyclus enaulus was in cavities at the base of mesquites or in burrows of vertebrates. It is likely that P. enaulus is the same species referred to as Artema atlanta by Fowler and Whitford (1983), but we cannot confirm this because no specimen was preserved. In our collecting on the Jornada del Muerto and surrounding area, A. atlanta, which is a Mediterranean spider in origin, was never collected. In contrast, Apollophanes texanus was collected in pitfall traps in creosotebush shrubland, grassland, and tarbush shrubland. The numerous ant-mimics (one Castianeira, seven Micaria, and one Synageles) reflect the rich ant fauna (41 species) of the Jornada del Muerto (Bestelmeyer and Wiens, 2001).
Of the 39 species recorded from sites on White Sands National Monument and vicinity, Muma (1979) noted 10 species collected only from dunes and 18 only from rangeland. Of 91 species recorded from Valley of Fires and vicinity, 5 were mostly in mixed grassland, 5 were mostly in rangeland (which was lower in species richness of plants), and 29 were mostly on the lava flow (including several small dictynids and several active species, such as salticids and philodromids). In Big Bend and vicinity, the campsite had 17 unique species, the sandy canyon had 29 unique species, and the two sites shared 20 of the total 63 species. Comparisons of shared and unshared spider faunas found at each site are shown in Table 2.
Seasonal associations also were important in this region, which receives most of its rainfall in summer, although in locally unpredictable patterns (Buffington and Herbel, 1965). The 25 most-common species (>10 individuals collected in autumn and spring 1999-2001) are listed in Table 3. Examples of taxa with adult stages in autumn at Jornada del Muerto were Micaria gosiuta, Dictyna personata, Habronattus ustulatus, Pellenes, Zorocrates karli, and Syspira analytica. Species with adults occurring mostly in spring were Micaria nye and Habronattus icenoglei. In some species, adults were present in autumn and spring: Habronattus conjunctus, Psilochorus imitatus, and Euryopis mulaiki. Oxyopes apollo and Mecaphesa (probably M. coloradensis) were collected in spring and autumn, but only as immatures. Crab spiders, formerly in Misumenops, are now considered to be in Mecaphesa (Lehtinen and Marusik, 2008). Immature crab spiders of the genus Mecaphesa were strongly associated with the bloom of many yellow flowers (Asteraceae) during autumn.
Species at White Sands National Monument and vicinity with strongly seasonal patterns were: Hogna carolinensis (June), Callilepis gosoga (June), and Psilochorus imitatus (June-August). At Valley of Fires and vicinity, representative species with strongly seasonal patterns were: Peckhamia scorpionia, Physocyclus enaulus, and Bassaniana utahensis (May-July); Titanoeca nigrella, Agelenopsis aperta, and Gnaphosa hirsutipes (June); Idionella sclerata, Tmarus angulatus, and Uloborus diversus (July); and Geolycosa rafaelana, Zelotes lasalanus (referred to as Z. chicano in Gertsch and Riechert, 1976), and Aphonopelma echinum (August-October). At Big Bend and vicinity, in Texas, seasonal patterns in families were: Dictynidae (February), Gnaphosidae and Salticidae (May-October), Lycosidae (May-December), and Oxyopidae (May-October.)
DISCUSSION--Although species of spiders often are distributed widely, local populations may be small. Although similar in families and genera present, the four sites differed markedly in the exact species present (Table 2). Of all species present, there were only three species collected at all four sites: Castianeira occidens, Apollophanes texanus, and Habronattus conjunctus. Eight additional species were at three sites, but not always at the same three sites. Obviously, the different time periods, collecting techniques, areas involved, and individual variation, make such studies difficult to compare. However, the two sites (Jornado del Muerto and Valley of Fires) that were most intensively collected by a variety of techniques had 118 and 92 species and it is likely that the other two may have had similar results if sampled by methods in addition to pitfall traps. Thus, a given site in the Chihuahuan Desert may have ca. 100 species of spiders, which may vary by ca. 65% of its fauna from other sites separated by distance or geological features, such as mountain ranges.
A recent study of affinity of ecoregions of ground-dwelling arthropods (Lightfoot et al., 2008) examined 121 species of spiders. Sites formed a transect from habitats in the Chihuahuan Desert, northward to a desert grassland, and into the Jemez Mountains of the southern Rocky Mountains. Spiders showed affinity to ecoregions and tracked a precipitation gradient. As expected, the most distant ecoregions (southern Rocky Mountains and Chihuahuan Desert) shared the fewest species (42). However, the southern Rocky Mountains shared only 34 species with neighboring shortgrass prairie, but shared 57 species with the Arizona-mountains region, which was much farther away.
Spiders are generalist predators and often are lumped in ecological studies as a single group.
However, spiders specialize in methods used to capture prey including: ambushers (Thomisidae), stalkers (Oxypidae, Salticidae), runners (Gnaphosidae, Lycosidae), orb-web weavers (Araneidae), tangled-web weavers (Dictynidae, Diguetidae, Theridiidae), and sheet-web weavers (Agelenidae, Linyphiidae; Wise, 1993). Species often are rare in space and time; thus, assessing them benefits greatly from multiple sampling methods and long-term collecting, as we have shown for the Jornada del Muerto.
Continued collection of spiders in the Chihuahuan Desert certainly will add to the lists given here, although here we provide a baseline for future studies, especially with reference to possible distributional shifts due to climatic change. As shown here, a number of species may be useful indicators of type or structure of habitat and of seasonal conditions. Some of these include wetland-adapted spiders such as Tetragnatha, grassland-adapted spiders such as Marpissa pikei, shrub-inhabiting spiders such as Paramarpissa albopilosa and Hamataliwa grisea, and ground or animal burrow-inhabiting spiders such as Loxosceles, Syspira analytica, Zorocrates karli, Hogna coloradensis, and Neoanagraphis chamberlini.
In addition to data from specimens we collected, collections and information were provided by D. Lightfoot, B. Cutler, G. B. Edwards, and P. Pache, J. Achata, provided the Spanish version of the abstract, and staff of the Jornada Experimental Range and Chihuahuan Desert Rangeland Research Center allowed access to sites. To all of these, we are indebted. This research was supported in part by the International Arid Lands Consortium, the United States Department of Agriculture Forest Service, the United States Department of Agriculture Cooperative State Research, Education, and Extension Service under grant 99R-12 to Y. Lubin, MEAW, and DBR, and the Agricultural Research Station, New Mexico State University.
Associate Editor was Jerry L. Cook.
Submitted 29 November 2008. Accepted 4 May 2010.
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* Correspondent: firstname.lastname@example.org
DAVID B. RICHMAN, * SANDRA L. BRANTLEY, DAVID H-C. HU, AND MARY E. A. WHITEHOUSE
Arthropod Museum, Department of Entomology, Plant Pathology and Weed Science, New Mexico State University, Las Cruces, NM 88003 (DBR)
Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131-0001 (SLB)
Gifford Pinchot National Forest, 10600 NE 51st Circle, Vancouver, WA 98682 (DH)
Australian Cotton Research Institute, Commonwealth Scientific and Industrial Research Organization, Entomology, Locked Bag 59, Narrabri, NSW 2390, Australia (MEAW)
Table 1--Taxa of spiders collected from the Jornada del Muerto, Dona Ana County (Muma, 1975), White Sands National Monument and vicinity, Otero County (Muma, 1975), and Valley of Fires near Carrizozo and vicinity, Lincoln County, New Mexico (Gertsch and Riechert, 1976), and Big Bend area, Presidio County, Texas (Broussard and Horner, 2006). Spiders listed only by genus usually were immature. Jornada del White Family Taxon Muerto Sands Cyrtaucheniidae Entychides arizonicus Entychides X Promyrmekiaphila Theraphosidae Aphonopelma X Aphonopelma echinum Filistatidae Filistatoides X X Kukulcania arizonica X X Kukulcania hibernalis Sicariidae Loxosceles apachea X Pholcidae Physocyclus enaulus X Psilochorus imitatus X X Psilochrous utahensis Psilochorus Diguetidae Diguetia canities X Diguetia imperiosa X Diguetia signata X Caponiidae Orthonops lapanus Oonopidae Gamasomorpha X Scaphiella hespera X Scaphiella (New Mexico) X Scaphiella (Texas) Mimetidae Mimetus hesperus X X Uloboridae Uloborus diversus Nesticidae Eidmannella pallida X Theridiidae Asagena fulva X X Dipoena abdita X Euryopis mulaiki X Euryopis scriptipes X Euryopis texana X Latrodectus hesperus X X Steatoda variata X Steatoda X Theridion leviorum Theridion X unidentified theridiids Linyphiidae Ceraticelus cf. laticeps Ceraticelus X Erigone whymperi X Erigone X Grammonota X Idionella sclerata Tapinocyba Tennesseellum formica Tetragnathidae Tetragnatha laboriosa X Araneidae Araneus arizonensis Araneus illaudatus X Argiope trifasciata X Larinia X Metepeira arizonica X Metepeira comanche X Lycosidae Neoscona oaxacensis X Alopecosa aculeata Alopecosa kochi X Camptocosa parallela X Geolycosa rafaelana X Hesperocosa unica X Hogna antelucana X Hogna carolinensis X Hogna coloradensis X X Hogna helluo Hogna X Pardosa sternalis X Pardosa Schizocosa mimula Varacosa gosiuta X Varacosa parthenus Oxyopidae Hamataliwa grisea X Oxyopes apollo X Oxyopes felinus Oxyopes lynx Oxyopes panther Oxyopes salticus Oxypes tridens X Peucetia longipalpis X Zorocratidae Zorocrates karli X Ctenidae Leptoctenus byrrhus Agelenidae Agelenopsis aperta X Agelenopsis longistyla X Agelenopsis naevia Dictynidae Argennina X Cicurina deserticola Cicurina ludoviciana X Cicurina parma X Cicurina varians X Cicurina Dictyna calcarata X Dictyna personata X X Dictyna terrestris X Dictyna tucsona Emblyna oasa X Emblyna reticulata X Emblyna stulta Mallos niveus Phantyna mulegensis X Amaurobiidae Coras Titanoecidae Titanoeca nigrella X Miturgidae Cheiracanthium inclusum X Syspira analytica X Anyphaenidae Anyphaena dixiana Anyphaena rita Liocranidae Neoanagraphis chamberlini X Clubionidae Clubiona oteroana Corinnidae Castianeira amoena Castianeira dorsata Castianeira nanella Castianeira occidens X X Castianeira 1 Castianeira 2 Corinna Phrurolithus apacheus Phrurotimpus certus Phrurotimpus woodburyi Piabuna brevispina X Piabuna X Scotinella pugnata Scotinella. X Septentrinna bicalcarata X Gnaphosidae Callilepis chisos Callilepis gertschi Callilepis gosoga X Callilepis mumai X Cesonia sincera X X Drassodes gosiutus X Drassodes saccatus Drassodes new species X Drassyllus insularis X Drassyllus mumai X Drassyllus notonus Drassyllus orgilus Drassyllus prosaphes Drassyllus new species A X Drassyllus new species B X Gnaphosa fontinalis Gnaphosa hirsutipes X Gnaphosa saxosa X Gnaphosa utahana Haplodrassus chamberlini X Haplodrassus Herpyllus bubulcus X Herppyllus. ecclesiasticu X Herpyllus hesperolus X Herpyllus propinquus X X Herpyllus schwartzi Micaria deserticola X Micaria emertoni Micaria gosiuta X Micaria imperiosa Micaria langtry Micaria longipes X X Micaria mormon X Micaria nye X Micaria porta X Micaria cf. triangulosa X Micaria X Nodocion eclecticus Nodocion cf. utus X Scopoides cambridgei Sergiolus angustus Sergiolus stella Urozelotes rusticus Zelotes anglo X Zelotes lasalanus X Zelotes tuobus X X Sparassidae Heteropoda venatoria Philodromidae Apollophanes margareta X Apollophanes punctipes X Apollophanes texanus X X Ebo dondalei X Ebo macyi X Ebo merkeli X Ebo mexicanus Ebo pepinensis X Ebo cf. texanus X Philodromus infuscatus utus Philodromus marginellus Philodromus cf. rufus group X Thanatus altimontis Thanatus coloradensis X Tibellus chamberlini X Thomisidae Bassaniana utahensis Mecaphesa celer Mecaphesa coloradensis X Mecaphesa rothi X Misumenoides formosipes X Synema neomexicanum X Tmarus angulatus Xysticus aprilinus X Xysticus cunctator X Xysticus lassanus X Xysticus lutzi X Xysticus new species X Xysticus Salticidae Chalcoscirtus diminutus X Habronattus cf. californicus Habronattus clypeatus X Habronattus coecatus Habronattus conjunctus X X Habronattus fallax Habronattus geronimoi X Habronattus hirsutus Habronattus icenoglei X Habronattus tranquillus X Habronattus tuberculatus X Habronattus ustulatus X Habronattus virgulatus X Habronattus new species X Marpissa lineata X Marpissa pikei Metacyrba taeniola X Metaphidippus manni Paramarpissa albopilosa X Peckhamia scorpionia Pelegrina arizonensis Pelegrina Pellenes limatus Pellenes new species X Phidippus apacheanus X Phidippus ardens X Phidippus californicus X Phidippus carneus X Phidippus octopunctatus Phidippus pius Phidippus vexans X Salticus peckhamae Sassacus papenhoei X Sitticus dorsatus Sitticus juniperi Synageles noxiosus X Synageles Terralonus shaferi X Tutelina similis Valley of Big Family Taxon Fires Bend Cyrtaucheniidae Entychides arizonicus X Entychides Promyrmekiaphila X Theraphosidae Aphonopelma Aphonopelma echinum X Filistatidae Filistatoides X Kukulcania arizonica X Kukulcania hibernalis X Sicariidae Loxosceles apachea X Pholcidae Physocyclus enaulus X Psilochorus imitatus Psilochrous utahensis X Psilochorus X Diguetidae Diguetia canities Diguetia imperiosa Diguetia signata Caponiidae Orthonops lapanus X Oonopidae Gamasomorpha Scaphiella hespera Scaphiella (New Mexico) Scaphiella (Texas) X Mimetidae Mimetus hesperus X Uloboridae Uloborus diversus X Nesticidae Eidmannella pallida Theridiidae Asagena fulva Dipoena abdita Euryopis mulaiki Euryopis scriptipes X Euryopis texana X X Latrodectus hesperus X Steatoda variata X X Steatoda Theridion leviorum X Theridion unidentified theridiids X Linyphiidae Ceraticelus cf. laticeps X Ceraticelus Erigone whymperi Erigone Grammonota Idionella sclerata X Tapinocyba X Tennesseellum formica X Tetragnathidae Tetragnatha laboriosa X Araneidae Araneus arizonensis X Araneus illaudatus Argiope trifasciata Larinia Metepeira arizonica X Metepeira comanche Lycosidae Neoscona oaxacensis X Alopecosa aculeata X Alopecosa kochi Camptocosa parallela Geolycosa rafaelana X Hesperocosa unica X Hogna antelucana Hogna carolinensis X Hogna coloradensis X Hogna helluo X Hogna Pardosa sternalis X Pardosa X Schizocosa mimula X Varacosa gosiuta X Varacosa parthenus X Oxyopidae Hamataliwa grisea Oxyopes apollo X X Oxyopes felinus X Oxyopes lynx X Oxyopes panther X Oxyopes salticus X Oxypes tridens X Peucetia longipalpis Zorocratidae Zorocrates karli X Ctenidae Leptoctenus byrrhus X Agelenidae Agelenopsis aperta X Agelenopsis longistyla X Agelenopsis naevia X Dictynidae Argennina Cicurina deserticola X Cicurina ludoviciana Cicurina parma Cicurina varians X Cicurina X Dictyna calcarata X Dictyna personata Dictyna terrestris Dictyna tucsona X Emblyna oasa Emblyna reticulata X Emblyna stulta X Mallos niveus X Phantyna mulegensis Amaurobiidae Coras X Titanoecidae Titanoeca nigrella X Miturgidae Cheiracanthium inclusum Syspira analytica Anyphaenidae Anyphaena dixiana X Anyphaena rita X Liocranidae Neoanagraphis chamberlini X Clubionidae Clubiona oteroana X Corinnidae Castianeira amoena X Castianeira dorsata X Castianeira nanella X Castianeira occidens X X Castianeira 1 X Castianeira 2 X Corinna X Phrurolithus apacheus X Phrurotimpus certus X Phrurotimpus woodburyi X Piabuna brevispina Piabuna Scotinella pugnata X Scotinella. Septentrinna bicalcarata Gnaphosidae Callilepis chisos X Callilepis gertschi X Callilepis gosoga Callilepis mumai Cesonia sincera X Drassodes gosiutus Drassodes saccatus X Drassodes new species Drassyllus insularis Drassyllus mumai X Drassyllus notonus X Drassyllus orgilus X Drassyllus prosaphes X Drassyllus new species A Drassyllus new species B Gnaphosa fontinalis X Gnaphosa hirsutipes X Gnaphosa saxosa Gnaphosa utahana X Haplodrassus chamberlini X Haplodrassus X Herpyllus bubulcus X Herppyllus. ecclesiasticu Herpyllus hesperolus X Herpyllus propinquus X Herpyllus schwartzi X Micaria deserticola Micaria emertoni X Micaria gosiuta Micaria imperiosa X Micaria langtry X Micaria longipes X Micaria mormon Micaria nye X Micaria porta Micaria cf. triangulosa Micaria X Nodocion eclecticus X Nodocion cf. utus X Scopoides cambridgei X Sergiolus angustus X Sergiolus stella X Urozelotes rusticus X Zelotes anglo X Zelotes lasalanus X X Zelotes tuobus Sparassidae Heteropoda venatoria X Philodromidae Apollophanes margareta Apollophanes punctipes Apollophanes texanus X X Ebo dondalei Ebo macyi Ebo merkeli Ebo mexicanus X Ebo pepinensis Ebo cf. texanus Philodromus infuscatus utus X Philodromus marginellus X Philodromus cf. rufus group Thanatus altimontis X Thanatus coloradensis Tibellus chamberlini X Thomisidae Bassaniana utahensis X Mecaphesa celer X X Mecaphesa coloradensis X Mecaphesa rothi Misumenoides formosipes Synema neomexicanum Tmarus angulatus X Xysticus aprilinus Xysticus cunctator X Xysticus lassanus X Xysticus lutzi X Xysticus new species Xysticus X Salticidae Chalcoscirtus diminutus X Habronattus cf. californicus X Habronattus clypeatus X Habronattus coecatus X Habronattus conjunctus X X Habronattus fallax X Habronattus geronimoi Habronattus hirsutus X X Habronattus icenoglei Habronattus tranquillus X Habronattus tuberculatus X Habronattus ustulatus Habronattus virgulatus Habronattus new species Marpissa lineata Marpissa pikei X Metacyrba taeniola Metaphidippus manni X Paramarpissa albopilosa Peckhamia scorpionia X Pelegrina arizonensis X Pelegrina X Pellenes limatus X Pellenes new species Phidippus apacheanus Phidippus ardens Phidippus californicus Phidippus carneus X Phidippus octopunctatus Phidippus pius X Phidippus vexans Salticus peckhamae X Sassacus papenhoei Sitticus dorsatus X Sitticus juniperi X Synageles noxiosus Synageles X Terralonus shaferi X Tutelina similis X X Table 2--Comparison of the spider fauna at four areas in the Chihuahuan Desert. Because collections at Jornada del Muerto, Dona Ana County, and Valley of Fires near Carrizozo and vicinity, Lincoln County, New Mexico, were obtained by several methods, they are probably the most comparable. Number Number Number Number of of of of species in Location families genera species common Jornada del 24 73 117 White Sands, 14 Muerto, Dona Valley of Fires, 35 County, New Big Bend, 19 Mexico White Sands 15 31 38 Jornada del Muerto, 14 National Valley of Fires, 14 Monument and Big Bend, 7 vicinity, Otero County, New Mexico (a) Valley of 23 66 91 Jornada del Muerto, 35 Fires near White Sands, 14 Carrizozo and Big Bend, 10 vicinity, Lincoln County, New Mexico Big Bend area, 21 47 63 Jornada del Muerto, 19 Presidio White Sands, 7 County Texas Valley of Fires, 10 (a) (a) Data were from pitfall samples only. TABLE 3--Life stages of the most abundant spiders ([greater than or equal to] 10 specimens) collected during spring and autumn over 3 years (autumn 1999, spring and autumn 2000, and spring 2001) on the Jornada del Muerto, Dona Ana County, New Mexico. Number of Number of adults and Number of adults and Number of subadults immatures subadults immatures Species in autumn in autumn in spring in spring Loxosceles 6 males, 1 3 males 3 apachea 5 females, 1 subadult male Physocyclus 6 males, 3 1 female 0 enaulus (a) 8 females, 3 subadults Psilochorus 9 males, 36 1 males, 17 imitatus 10 females, 2 females, 3 subadults 4 subadults Euryopis 11 males, 4 3 males, 0 mulaiki (a) 4 subadults 2 females Latrodectus 1 female, 3 1 subadult 7 hesperus (b) 5 subadults Steatoda 2 females 2 1 male, 6 fulva 2 females Camptocosa 7 subadults 35 8 males, 11 parallela (b) 3 females, 6 subadults Geolycosa 1 female, 24 1 male, 6 raphaelana 2 subadults 3 subadults Hesperocosa 0 0 21 males, 0 unica (b) 2 females Dictyna 5 males, 6 1 male, 3 personata 5 subadults 7 subadults Dictyna 7 females, 0 11 males, 0 terrestris (b) 1 subadult 29 females Oxyopes 0 33 10 males, 18 apollo (c) 3 females, 3 subadults Oxyopes 4 subadults 243 41 males, 60 tridens (c) 6 females, 28 subadults Syspira 1 male, 4 8 males, 5 analytica 1 subadult 1 female, 2 subadults Micaria 4 males, 2 0 102 gosiuta 19 females Micaria 0 3 3 males, 0 nye 5 females Ebo macyi 3 males, 0 0 19? 2 females Thanatus 1 male, 27 2 males, 41 coloradensis (b) 5 females, 3 females, 9 subadults 12 subadults Tibellus 10 subadults 131 2 males, 72 chamberlini (c) 1 female, 38 subadults Habronattus 0 4 2 males, 2 clypeatus 3 females, 1 subadult (a) Occurs almost exclusively in shrubland. (b) Occurs almost exclusively in grassland. (c) Occurs rarely outside of grassland.