A New Species of the Spider Genus Zelotes (Araneae, Gnaphosidae) from California

3 Pages·1999·2.5 MB·English

by  Norman I Platnick

1999. The Journal of Arachnology 27:672-674
RESEARCH NOTE
A NEW SPECIES OF THE SPIDER GENUS ZELOTES
(ARANEAE, GNAPHOSIDAE) FROM CALIFORNIA
Recent sampling near Lake Skinner in where clay has been deposited by runoff. Be-
southern California has produced the first tween the shrubs, the substrate is bare except
known specimens ofa small species ofZelotes for sparsely distributed Schismus grass and a
that seems mostclosely related toZelotesnan- few relatively large surface rocks. Leaf litter
nodes Chamberlin 1936, known only from accumulates only beneath a few of the more
southeastern Oregon, Nevada, and Utah (Plat- closely grouped shrubs. Because of the hard
nick & Shadab 1983). We describe here this ground surface, few burrows or surface open-
new species and provide some notes on its ings of any kind were found; those that were
habitat and on other spiders taken in the same noted opened in surface depressions or in the
samples. sandier sections of the plot.
Lake Skinner is surrounded by undisturbed Three other gnaphosid species were col-
Riversidian coastal sage scrub (Westman lected in the June samples from both plots:
1983) in the Southwestern Riverside County Callilepis gosoga Chamberlin & Gertsch
Multispecies Reserve. The new species was 1940, Cesonia classica Chamberlin 1924, and
collected in June from pitfall traps set in two Drassyllus insularis (Banks 1900). The first
m
sampling plots, approximately 600 and 450 site also provided Drassyllus fractus Cham-
m, respectively, from the lake’s northeast berlin 1936 and (the probably introduced) Ze-
shore. The first site (on a north-facing, rela- lotes nilicola (O. R-Cambridge 1874) in June
tively steep slope), providing one male, has a samples, whereas the second site produced
very dense shrub cover, primarily ofArtemisia Gnaphosa californica Banks 1904, Micaria
californica Lesson (California sage) and sec- jeanae Gertsch 1942, and Zelotes monachus
ondarily of Erigonum fasciculatum Bentham Chamberlin 1924. Over70% oftheBlabomma
&
(California buckwheat) and Salvia mellifera sanctum Chamberlin Ivie 1937 specimens
E. Greene (black sage) with Salvia apiana collected (from a possible 24 plots) were tak-
Jepson (white sage) interspersed among the en in December samples from the first site.
major shrub components. The composition ra- The second site produced specimens of ap-
tio of the three major shrubs is approximately parently undescribed species of Blabomma,
4:2:1. The soil consists ofdecomposed granite Aptostichus (both in December samples), and
ofrelatively fine particle size mixed withclay; Psilochorus (in June samples).
large exposed rocks are absent. The substrate The format of the description follows that
is essentially bare, with sparsely distributed of Platnick & Shadab (1983). We thank Mo-
annual Schismus grass or, in less exposed ar- hammad Shadab of the American Museum of
eas, a thin lichen cover. Only near the bases Natural History for help with the illustrations.
of shrubs is any leaf litter present.
The second site (on a south-facing, gentle Zelotes skinnerensis new species
slope), providing the female and a second Figs. 1-4
male, is vegetated by sparsely distributed —
shrubs, primarily E.fasciculatum and second- Types. Male holotype and female allo-
arily A. californicum, with a few scattered S. type taken in pitfall traps at an elevation of
mellifera shrubs. The composition ratio ofthe ca. 470 m in a site 450 m from the NE shore-
two major shrubs is approximately 2.5:1. The line of Lake Skinner, Southwestern Riverside
soil here also consists of decomposed granite County Multispecies Reserve, Riverside
but has acoarserparticle size and amuch low- County, California (<3, 13-16 June, 1998; $
er clay content, except in surface depressions 6-10 June 1998, both by TR. Prentice), de-
672
PLATNICK & PRENTICE 673
—
Figures 1-4. Zelotes skinnerensis new species. 1, Left male palp, ventral view; 2, Same, retrolateral
view; 3, Epigynum, ventral view; 4, Same, dorsal view.
posited in American Museum of Natural His- interdistances: AME 0.03, ALE 0.05, PME
tory courtesy of Metropolitan Water District 0.04, PLE 0.05; AME-AME 0.04, AME-ALE
ofSouthern California and R. Redak (Dept, of 0.01, PME-PME 0.05, PME-PLE 0.00, ALE-
Entomology, U—niv. of California, Riverside). PLE 0.05; MOQ length 0.12, frontwidth0,10,
Etymology. ^The specific name refers to back width 0.12. Embolus shorter than in Z.
the type locality. nannodes, without prolateral hump (Figs. 1,
Diagnosis.-“This species, with its trans- 2). Leg spination: tibia IV pi-0-1; metatarsi:
verse embolus extending across the distal III pO-2-2, V2-0-0, rO-1-2; IV pO-2-2.
edge of the male palpal bulb, belongs to the Female: Total length 3.30. Carapace 1.14
laccus subgroup of the genus, and is likely to long, 0.88 wide. Femur II 0.67 long. Eye sizes
be confused only with what appears to be its and interdistances: AME 0.03, ALE 0.05,
sister species, Z. nannodes. Males have the PME 0.05, PLE0.05; AME-AME0.04, AME-
distal edge of the terminal apophysis rounded ALE 0.01, PME-PME 0.04, PME-PLE 0.04,
(Fig. 1), whereas inZ. nannodes the prolateral ALE-PLE 0.04; MOQ length 0.11, front width
edge ofthe terminal apophysis bears a sharply 0.10, back width 0.14. Epigynum with trian-
pointed projection (Platnick & Shadab 1983: gular median plate longer than in Z. nannodes
figs. 231, 235). Females of the new species (Figs. 3, 4). Leg spination: tibiae: III vlr-2-2;
have a longer median epigynal plate (Fig. 3) IV pi-0-1; metatarsi: I vO-0-0; II vlr-0-0; III
than that found in females of Z. nannodes pO-2-2, V2-0-0, rO-1-2; IV pO-—2-2.
(Platnick & Shadab 1983: fig. 233); the single Othermaterial examined. One maletak-
m
female available for study has what appear to en in pitfall trap at an elevation of ca. 480
be fragments of the male embolus extending in a site 600 m from the NE shoreline ofLake
from the epigynal openings and partially ob- Skinner, Southwestern Riverside County Mul-
scuring the medi—an epigynal plate. tispecies Reserve, Riverside County, Califor-
Description. Male: Total length 2.49, nia (6-10 June 1998, T.R. Prentice), deposited
2,65. Carapace 1.08, 1.14 long, 0.81, 0.82 in University of—California, Riverside.
wide. Femur II 0.64, 0.66 long. Eye sizes and Distribution. Known only from the type
674 THE JOURNAL OF ARACHNOLOGY
locality in Riverside County, southern Cali- Norman I. Platnicki Division of Inverte-
fornia. brate Zoology, American Museum of Nat-
ural History, Central Park West at 79th
LITERATURE CITED Street, New York, New York 10024 USA
Platnick, N.L & M.U. Shadab. 1983. A revision of
the American spiders ofthe genus Zelotes. Bull. Thomas R. Prentice: Department of En-
American Mus. Nat. Hist., 175:97-192. tomology, University of California, River-
Westman, W.E. 1983. Xeric Mediterranean-type side, California 92521 USA
shrubland associations of Alta and Baja Califor-
nia and the community/continuum debate. Ve- Manuscript received 4 December 1998, revised 15
getatio, 52:3-19. March 1999.