Paruroctonus silvestrii ((Borelli 1909)
Vejovis silvestrii Borelli, 1909: 225-227;
Ewing, 1928: 14
Vaejovis silvestrii: Ewing, 1928: 14; Hjelle, 1972: 6, 23-26, 27,
fig. 11, 47, 48, 51.
Vejovis boreus (part; MIS): Gertsch, 1958: 6.
Vejovis (Paruroctonus) silvestrii: ►Gertsch & Soleglad,
1966: 15-20, fig. 1, 4, 5, 7, 9, 27, 28.
Paruroctonus silvestrii: Williams, 1972: 3, 4, 8; Soleglad, 1973b:
355; Williams, 1976: 2; Williams, 1980: 32, 39-41, fig. 39, 46; Hjelle,
1982: 98; Haradon, 1985: 24, 40; Williams, 1987b: 329; Kovarík, 1998:
144; Beutelspacher, 2000: 69, 136, 146, 152, map 39; Sissom, 2000:508;
Soleglad & Fet, 2003b: 6, fig. 7; Soleglad & Fet, 2003a: 8, 67, 150,
figs. 107, B-1.
Paruroctonus silvestrii (Borelli), female.
Photograph by W. David Sissom
Borelli 1909: Holotype (female) from Sierra Madre, Los
Angeles County, California, USA in the Museo Zoologico, Turin, Italy.
Gertsch and Soleglad 1966
DIAGNOSIS: Distinct species (figs. 4, 5) resembling
boreus in general appearance but differing in following features:
carapace heavily mottled with black pattern and tergites of preabdomen
having transverse black bands continuous to posterior margins. Females
attaining larger size, having shorter and stouter cauda with heavier
telsons, and longer and less granulose hands on chelae. Sexual
dimorphism more pronounced, and considerably smaller males having more
slender cauda and quite thin, weak hands. Ventral surfaces of cauda
bearing one more pair of setae on each segment. Eyes of medium size and
somewhat smaller than those of boreus.
COLORATION: Similar to that of boreus in both sexes but more boldly
marked in black. Base color yellow to dull orange or tan, with well
marked black pattern as shown in figures 7 and 9. Eyes and eye tubercles
black. Carapace typically bright yellow, with intricate pattern of black
bands and stripes radiating from pale midline. Tergites I-VI of
preabdomen with transverse black bands covering most of surface, dark to
posterior margins; each tergite enclosing pair of oval yellow markings
near center and irregular series of spots on each side. Tergite VII much
paler than tergites in front, without pronounced pattern. Cauda yellow
to orange, unmarked above, but with series of four dusky lines below on
segments I-IV as in boreus; these markings in some cases faint or
lacking, but well indicated in many females and broader and darker in
STRUCTURE: Similar to that of boreus except as indicated below. Males
much smaller than females, with proportionately thinner cauda.
Measurements given in table 2.
Carapace: Shape of carapace of female from northeast of Lucia, Monterey
County, California: Anterior margin straight, set with six suberect
bristles; width at side eyes four-sevenths of width at posterior margin;
length and breadth about equal. Median eyes of average size situated
just forward of midpoint of carapace; width of median diad about
one-fifth of width of carapace at that point (22/110). Surface polished
in spite of numerous granules situated chiefly on dark pattern areas and
seemingly coarser and more conspicuous than corresponding granules of
boreus; carapace of male more coarsely granulate than that of females.
Preabdomen: With typical sculpturing of boreus.
Cauda: Similar to that of boreus (figs. 16, 17) on all surfaces.
Obsolete inferior median keels of segments I-IV with 3-4-4-5 pairs of
Telson: Essentially smooth: vesicle globular, somewhat less slender than
that of boreus; sting gradually curved, half as long as vesicle.
Pectines: Pectinal teeth of female 18-22, of male 25-29.
Chelicerae: Similar in both sexes and differing little from those of
boreus (figs. 46-48). Lower margin of fixed fingers usually with two
distinct, dusky nodules at base. Lower margin of movable finger with
keel dissected into four to seven distinct, irregularly formed teeth.
Pedipalps: Those of female of medium length, with heavy hands and
fingers as shown in figure 28. Basal segments with all carinae coarsely
granulated. Chelae greatly incrassated, with all eight carinae distinct
as in boreus but somewhat smoother and less granulose. Inner keels of
fingers rather smooth, weakly scalloped, and armed as in boreus.
Pedipalp of male far more slender than that of female as shown in figure
27, with carinae rather weak and weakly granulated as compared with
those of female.
Walking legs: With setation essentially as in boreus, but protarsi with
fewer and quite irregularly spaced setae.
"DIAGNOSIS.-Dorsal surface of carapace and mesosoma with underlying dusky or dark markings, dusky markings continuous to posterior margin of each mesosomal tergum; position of ventromedian and ventrolateral keels of metasoma with underlying dusky or dark markings: base color of cuticle dull orange or yellow. Metasoma with ventrolateral keels weakly developed
and smooth. ventromedian keels obsolete, position of ventromedian keels of segments 1-IV set with 3, 4, 4, 5 pairs of setae, respectively; chelicera with ventral margin of fixed finger usually with 2 distinct, dusky denticles at base; ventral margin of movable finger with about 4-7 irregular denticles; pectine teeth 18-22 in females, 25-29 in males.
Similar to P. arnaudi, but distinguished by obsolete ventromedian metasomal keels (not smooth to lightly crenulate)."
AMERICA. México (Baja California Norte), USA (southern California).
California: Modoc County: Adin Summit, September 18, 1961 (W. Ivie, W. J.
Gertsch), one immature. El Dorado County: Ranger Station, 12 miles east of
Kyburz, October 9, 1945 (G. Linsley, J. W. MacSwain, R. F. Smith), female.
Marin County: Mt. Tamalpais, May 13, 1934, female. San Joaquin County: One
and one-quarter miles east of Atomic Energy Commission Explosive Test Site,
Corral Hollow Valley, July 31, 1965 (K. Hom), pit trap, two females. Contra
Costa County: Four miles south of Antioch, April 9, 1945 (R. F. Smith), two
males, six females; Antioch, sand dunes, March 16, 1951 (E. I. Schlinger),
male. Alameda County: Corral Hollow, 5 miles west of Tracy; April 19, 1945
(R. F. Smith, 0. Bacon), two immature females, March 8, 1945 (R. F. Smith,
A. E. Michelbacher), female. Corral Hollow, October 1, 1945 (J. W. MacSwain),
female. Canyon north of Mitchell Ravine, August 26, 1965 (K. Hom), pit trap,
male. Tuolumne County: Four miles west of Pinecrest, July 8 and 16, 1961 (J.
Rozen), two males, female; Reservoir Canyon, San Luis Obispo, August 15,
1959 (V. Roth, W. J. Gertsch), male. San Benito County: Four miles east of
Panoche, July 28, 1965 (K. Hom, V. Lee), female. Fresno County: Cedar Grove,
Kings River Canyon, 4633 feet, July 16, 1952 (W. J. Gertsch), female.
Monterey County: Indian Creek, King City-Memorial Park Road, January 16,
1956 (H. B. Leech), under stones, male. Junipera Serra Peak, 5800 feet,
Santa Lucia Mountains, August 9, 1956 (L. Salanave), male, August 14, 1956
(B. Hargis), male, August 15-16, 1956 (H. B. Leech), under stones, male, two
females; Seaside, behind beach dunes, June 24, 1957 (T. J. Cohn), female
with boreus pattern; Cone Peak Trail, 4100-5100 feet, 3.5 air miles
northeast of Lucia, August 18, 1957 (T. J. Cohn), male, four females. Tulare
County: Near Ash Mountain, Sequoia National Park, July 9, 1958 (W. J.
Gertsch, V. Roth), immature female. Ventura County: Wheeler Springs, July 2,
1958 (W. J. Gertsch, V. Roth), three immature females; 10 miles north of
Wheeler Springs, July 2, 1958 (V. Roth), female; Mt. Pinos, July 31, 1961
(V. and B. Roth), male, two females. Los Angeles County: Los Angeles; July
30, 1948 (C. and P. Vaurie), immature female, March, 1922 (G. Grant), male,
immature, November-December, 1912 (D. D. R. Ruthling), male; Lower Shake
Camp, Pine Canyon, July 6, 1954 (W. A. McDonald), female; Crystal Lake, San
Gabriel Mountains, September 29, 1965 (J. and W. Ivie), two females. Orange
County: Santa Ana Canyon, 12 miles east of Capistrano, March 30, 1960 (W. J.
Gertsch), male. Riverside County: Riverside, 500-800 feet, July 14, 1907,
female; Keen Camp area, San Jacinto Mountains, April 26, 1961 (W. J. Gertsch),
male. San Diego County: Mt. Palomar State Park, July 13, 1953 (W. J. and J.
W. Gertsch), immature females; Del Mar, April 1, 1956 (J. A. Comstock),
female; 6 miles northwest of Campo, on Hauser Creek, October 1, 1961 (W. J.
Gertsch, W. Ivie, V. Roth), female, immature female. Baja California Norte:
La Rumarosa; 43 miles west of Mexicali, October 7, 1961 (O. Clarke), female,
October 1, 1961 (V. Roth), immature; 10-15 miles south of La Rumarosa, July
14, 1961 (V. Roth), female; Ensenada, March 10, 1946 (B. Malkin), immature
female; 17 miles north of Colonia Guerrero, April 29, 1961 (W. J. Gertsch,
V. Roth), male.
California Norte, Mexico: 4.8 km S Mexicali-Tecate hwy.. Sierra Juarez, 20-VI-1973 (Williams. Blair); 16.6 km SW Rumorosa, 25-VII-1963 (LBS); El Progreso, head of El Tajo Canyon, 12-IX-1958 (Truxal, LACM); Sierra Juarez, Sawmill, 9-VII-I969 (Williams, Lee); Laguna Hanson, 7-X-1938 (Meadows, LACM); 18 km SE Ojos Negros, 15-VII-I969 (Williams. Lee): 19 km E Ensenada. 15-VI I- 1969 (Williams, Lee); NE slope N Los Coronados
Islands, 20-VI-196I (Farmer); between Rancho Filipinas and Rancho Viejo, 30-VI-I962 (Lindsay); Punta Banda. 10-VII-1969 (Williams, Lee); Puerto Santo Tomas, ll-VII-1969 (Williams, Lee); 0.8 km W La
Milla Ruins, Sierra Juarez, 21-VI-1973 (Williams, Blair); 2.6 km N Punta Calaveras,
Hematite Mine. I3-VII-1962 (Parrish); Arroyo Seco. 9-II-1964 (Allen, Croulet); 26 km E Meling Ranch, Sierra San Pedro Martir. 13-VII-1969 (Williams. Lee); La Grulla. Sierra San Pedro Martir. 5-IX-1961 (Parrish, Lindsay, Sloan); Mike's Sky Ranch. Sierra San Pedro Martir. 14-19-VI-1973 (Williams, Blair); SW side La Encantada Meadow. Sierra San Pedro Martir, 5-IX-I961 (Parrish); 0.5 km SW Socorro, San Pedro Martir foothills, 2-IX-196I (Parrish); 8.0 km N
Colonia Guerrero, 23-VIII-1961 (Parrish); El Progreso, l-IV-1969 (Williams).
Beutelspacher (2000) lists a record
of P. silvestrii from Sonora (Benjamin Hill); this record was based
on a misidentified specimen of Vaejovis spinigerus (Wood). Williams
(1980) stated, "One of the
most abundant scorpions in the higher elevations of the northern parts of the Baja California. It occupies a wide variety of ecological conditions, but is generally not found east of the Sierra Juarez and Sierra San Pedro Martir. Commonly encountered in coastal sand dunes, chaparral foothills, oak grassland,and coniferous forests."
(Borelli), male. Photograph by W. David Sissom
(Borelli), male. Photograph by Warren Savary