Parobisium Chamberlin 1930

JAMES C. COKENDOLPHER & JEAN K. KREJCA, 2010, A NEW CAVERNICOLOUS PAROBISIUM CHAMBERLIN 1930 (PSEUDOSCORPIONES: NEOBISIIDAE) FROM YOSEMITE NATIONAL PARK, U. S. A., Occasional Papers of the Museum 297, pp. 1-28 : 3-4

Genus Parobisium Chamberlin 1930

Neobisium (Parobisium) Chamberlin 1930:17 ; Beier 1932:84; Morikawa 1960:112-113; Hoff 1961:427.

Parobisium Chamberlin : Chamberlin and Malcolm 1960:112-113; Chamberlin 1962:123; Harvey 1991:394; Mahnert 2003:744-745.

Diagnosis.—Fixed chelal finger with a compact subterminal cluster of only three tactile setae (et, it, est) and a more diffuse subbasal to basal cluster of five tactile setae (isb, ist, ib, esb, eb); both clusters of setae number four (et, est, it, ist / esb, eb, isb, ib) in other genera, and seta ist is subterminal instead of subbasal in position ( Chamberlin 1962).

Subordinate taxa and distribution.— Parobisium now consists of 16 described species and four additional subspecies ( Harvey 2009): East Asia: China (three species), Japan (four species), South Korea (two species); North America: western U.S.A. (seven species).

North American ( U.S.A.) taxa:

KEY TO ADULTS OF THE GENUS PAROBISIUM OF NORTH AMERICA

Galea absent ( Chamberlin 1962: Fig. 7H ); large species, palpal femur and tibia each longer than 2.0 mm........................................... Parobisium charlotteae Chamberlin 1962 (troglophile, Deschutes County, Oregon)

Galea present, small rounded sclerotic knob ( Figs. 25-26 , 28 ); small to medium sized species, palpal femur and tibia each 0.5-1.8 mm long..................................................2

Anterior eyes reduced in size or absent, posterior pair absent; palpal femur longer than 1.4 mm ...................................................................................................................................3

Two pairs of eyes well developed; palpal femur shorter than 0.85 mm ...................................................4

Epistomal process a small extension ( Fig. 5 ), palp patella with bulge on mesal margin ( Figs. 14-15 ), palpal hand elongated in dorsal and ventral view ( Fig. 15 )....................................................... Parobisium yosemite Cokendolpher and Krejca , n. sp. (troglobite, Mariposa County, California)

Epistomal process absent, palpal patella smooth on mesal margin, palpal hand rounded in dorsal and ventral view ( Schuster 1966: Fig. 12 )………………………………........... .................................................................................................. Parobisium hesperum ( Chamberlin 1930) (humus, Clatsop County, Oregon; Shasta County, California)

Smaller robust species, palpal femur 0.57-0.64 mm long, California ......................................................5

Medium sized species, palpal femur 0.72-0.84 mm long, Utah, Colorado ..............................................6

Galeal knob a long, low crest ( Schuster 1966: Fig. 9 ); patella II with 11-12 setae; coxa IV with about 12 setae; anterior genital area (sternite II) of male with about 20 setae …......................................................... Parobisium hastatum Schuster 1966 (humus, El Dorado, Marin, Mariposa, Napa, Placer, Sonoma, Yolo counties, California)

Galeal knob a short, rounded crest ( Schuster 1966: Fig. 11 ); patella II with 18 setae; coxa IV with about 16 setae; anterior genital area (sternite II) of male with about 30 setae........................................................... Parobisium hesternum Schuster 1966 (humus, El Dorado, Mariposa counties, California)

Posterior margin of carapace with 10-12 setae; palpal femur of male 3.9-4.1 times as long as broad, chela 3.3-3.4 times as long as broad; chelal fingers with 45-59 marginal teeth ……………….................. Parobisium vancleavei ( Hoff 1961) (beneath rocks in pinyon-juniper woodland, Montezuma County, Colorado)

Posterior margin of carapace with 8-10 setae; palpal femur of male 4.2-4.4 times as long as broad; chela 3.7-3.8 times as long as broad; chelal fingers with 62-82 marginal macrodenticles ………………………………….....…. Parobisium utahensis Muchmore 1968 (moss on rocks, Cache County, Utah)

Figures

Figures 7-8. Paratype female (TTU-Z 51548) Parobisium yosemite, n. sp. from Indian Cave, Yosemite National Park. 7, palp and leg coxae. 8, left palp coxa. Rounded median maxillary lyrifissures (arrows pointing left - see text) and curved posterior maxillary lyrifissures (arrows pointing right). Scale = 0.15 mm.

Figures 24-25. Paratype female (TTU-Z 51548) Parobisium yosemite, n. sp. from Indian Cave, Yosemite National Park. 24, upside-down view of palp hand (moveable finger should open ventrally), setal positions marked as well as in another view in Fig. 23 (damage to base of chela and basal portion of hand broken off); 25, lateral view of chelicera; seven setae on the hand and a setae on moveable finger are highlighted in yellow, macrodenticles of the fingers as well as the lyrifissure (= lf) are also marked.

Figures 26-27. Paratype female Parobisium yosemite, n. sp. (TTU-Z 51548) from Indian Cave, Yosemite National Park. 26, lateral view of chela tips; 27, mesal side of chela; five long hirsute filaments (arrow on right), plus three shorter hirsute filaments (arrow on left) in rallum.

Figures 28-29. Galea on moveable finger of chelicera of paratype female (TTU-Z 51548) Parobisium yosemite, n. sp. from Indian Cave, Yosemite National Park. 28, lateral aspect with 4 numbered pore positions; depression above 1 does not appear to be a pore; 29, anterior close-up of pores. Pores at 0.6 µm diameter (measured at much higher resolution). Numbers 1, 4 are certainly pores, but the openings are less clear of the depressions at 2 and 3, but likely pores of the galea (spinneret).

Figures 5-6. Parobisium yosemite, n. sp. from Indian Cave, Yosemite National Park. 5, holotype male (TTU-Z 51528) carapace, dorsal (anterior is to left; posterior pair of lyrifissures added and indicated by arrows - see text). 6, female (TTU-Z 51548) tarsus IV claw with bifurcate setae (indicated by arrows). Scale, 5 = 0.25 mm, 6 = 0.05 mm.

Figures 13-17. Parobisium yosemite, n. sp. from Indian Cave, Yosemite National Park. 13, holotype TTU-51528, internal male genitalia (internal piece of genital operculum) with six and seven socketed spines bounded by larger triangular denticles. 14-17 male paratype TTU-Z51576. 14, enlargement of palp patella base showing medial buldge, ventral aspect; 15, palp, ventral aspect; 16, leg I, posterior aspect; 17, leg IV, posterior aspect. Scales, 13 = 0.063 mm, 14 = 0.167 mm, 15-17 = 0.5 mm.

Figures 11-12. Parobisium yosemite, n. sp. from Indian Cave, Yosemite National Park (TTU-Z 51528). 11, male genital sternites. 12, paratype female (TTU-Z 51548) genital sternites with seven pairs of setae, arrows point to pair of lyrifissures. Scales, 11 = 0.1 mm, 12 = 0.05 mm.

Figures 9-10. Paratype female (TTU-Z 51548) Parobisium yosemite, n. sp. from Indian Cave, Yosemite National Park. 9, sternites III and IV with spiracles positions noted with arrows; the trachea are easily visible, pleural membrane granulations indicted by circle. 10, enlarged view of genitalia: 1 = atrium, 2 = left lyrifissure, 3 = left group of seven setae on genital sternite, 4 = series of pores of lateral apodeme, 5 = medium genital sac below the pore covered gonosacs, la = part of cribriform plate of the lateral apodeme. Scales, 9 = 0.15 mm, 10 = 0.1 mm.