Larca boulderica, Harvey & Steinmann, 2024

Harvey, Mark S. & Steinmann, David B., 2024, A new troglomorphic species of Larca (Pseudoscorpiones, Larcidae) from Colorado, ZooKeys 1198, pp. 279-294 : 279

Larca boulderica sp. nov.

Figs 6 , 7-9 , 10-18 , 19-21

Material examined.

Types: U.S.A.: Colorado: Boulder County: holotype male, Mallory Cave , 39°58.45'N, 105°17.37'W, 7000 ft (2140 m) a.s.l., 29 November 2008, under rock, dark zone of cave, D. Steinmann (DMNS) . Paratypes: 4 females, collected with holotype (DMNS) ; 1 male, collected with holotype (WAM T162363) ; 1 female, same data as holotype except 12 November 2009 (DMNS) ; 1 female, same data as holotype except 12 November 2009 (WAM T162059) .

Diagnosis.

Larca boulderica most closely resembles L. aalbui , L. rotunda and L. welbourni as all have four trichobothria on the movable chelal finger (Figs 14 , 15 ) and trichobothrium ist is closer to ib than to isb (Figs 14 , 15 ). The only other species with four trichobothria, L. cavicola and L. guadalupensis , have trichobothrium ist situated midway between ib and isb. Larca Archeolarca rotunda and L. welbourni have a rounded chelal hand, whereas L. aalbui and L. boulderica have a thinner hand (Figs 12 , 13 ). Larca boulderica differs from L. aalbui by the positions of trichobothria st and t (separated by at least one areolar diameter in L. boulderica but by less than one areolar diameter in L. aalbui ), and the less slender pedipalpal segments [e.g., 4.57-4.59 (♂), 4.07-4.71 (♀) × and patella 3.09-3.22 (♂), 3.21-3.32 (♀) × longer than broad in L. boulderica (Figs 12 , 13 ); femur 5.3-5.9 × and patella 3.9-4.35 × longer than broad in L. aalbui ].

Description

(adults). Colour: most body parts pale yellow-brown, genital region of female and legs slightly paler (Figs 6 - 9 ).

Setae and cuticle: setae long, usually curved, distally acuminate; most cuticular surfaces granulate.

Chelicera: with 4 (rarely 5) setae on hand, with sbs usually absent, and 1 subdistal seta on movable finger; all setae acuminate; seta bs slightly shorter than others; with 2 dorsal lyrifissures and 1 ventral lyrifissure; galea of ♂ short with terminal bifurcation (Fig. 16 ), of ♀ long and slender with 3 terminal to subterminal rami (Fig. 17 ); rallum of 4 blades, the most distal blade with several serrations on leading edge, other blades smooth; serrula exterior with 16 (♂), 18 (♀) blades; lamina exterior present.

Pedipalps: Pedipalp (Figs 12 , 13 ): most surfaces of trochanter, femur, patella and chelal hand lightly and granulate, chelal fingers smooth; trochanter, femur, patella and chelal hand with prominent, curved, slightly denticulate setae arranged sparsely; patella with 3 small sub-basal lyrifissures; trochanter 1.85 (♂), 1.79 (♀), femur 4.57-4.59 (♂), 4.07-4.71 (♀), patella 3.09-3.22 (♂), 3.21-3.32 (♀), chela (with pedicel) 4.36-5.00 (♂), 3.83-4.03 (♀), chela (without pedicel) 4.09-4.78 (♂), 3.60-3.81 (♀), hand (with pedicel) 2.09-2.33 (♂), 1.83-1.87 (♀) × longer than broad, movable finger (with pedicel) 0.96-1.05 (♂), 0.97-1.03 (♀) × longer than hand. Fixed chelal finger with 8 trichobothria, movable chelal finger with 4 trichobothria (Figs 14 , 15 ): eb, esb, ib and ist situated subbasally, est, isb and it submedially, et subdistally, est slightly distal to it, ib opposite esb, and ist distal to esb; b and sb situated subbasally, and st and t situated submedially, with st situated very close to t, separated by slightly more than 1 areolar diameter; patch of microsetae not present on retrolateral margin of fixed chelal finger near et. Venom apparatus present in both chelal fingers, venom ducts not visible. Chelal teeth rounded, very low; fixed finger with 30 (♂), 30 (♀) teeth; movable finger with 29 (♂), 28 (♀) teeth; accessory teeth absent.

Cephalothorax: carapace (Figs 9 , 10 ): 0.73-0.75 (♂), 0.79-0.83 (♀) × longer than broad; anterior margin straight; with 2 pairs of rounded corneate eyes, tapetum present; with 25-41 (♂), 24-30 (♀) setae, arranged with 6-8 (♂), 4-6 (♀) near anterior margin, 8-17 (♂), 10-15 (♀) in prozone, 7-8 (♂), 7 (♀) in metazone and 4-6 (♂), 3-4 (♀) near posterior margin; with 1 deep, broad median furrow. Coxal region: manducatory process rounded with 1 distal seta, 1 small sub-oral seta, and 12 (♂), 9 (♀) additional setae; median maxillary lyrifissure large, rounded and situated submedially; posterior maxillary lyrifissure rounded. Coxae I to IV becoming progressively wider. Chaetotaxy of coxae I-IV: ♂, 8: 8: 8: 12; ♀, 8: 8: 7: 11.

Legs: femora I and II longer than patellae; junction between femora and patellae III and IV very angulate; femora III and IV much smaller than patellae III and IV; femur + patella of leg IV 5.21 (♂), 4.81 (♀) × longer than broad (Fig. 18 ); metatarsi and tarsi not fused; tarsus IV without tactile seta; subterminal tarsal setae arcuate and acuminate; claws simple; arolium much longer than claws, not divided.

Abdomen: tergites II-VIII and sternites IV-VIII of male and female with medial suture line fully dividing each sclerite. Tergal chaetotaxy: ♂, 7: 8: 8: 11: 11: 11: 11: 10: 6: 6 (arranged T4T): 6: 2; ♀, 4: 6: 10: 11: 12: 11: 12: 11: 10: 8 (arranged T6T): 4: 2; tergites I-X uniseriate. Sternal chaetotaxy: ♂, 22: (0) 7 [3 + 3] (0): (0) 21 (0): 8: 9: 8: 8: 6: 6: 4: 2; ♀, 13: (0) 12 (0): (0) 7 (0): 8: 7: 8: 9: 7: 6: 4: 2; sternites IV-X uniseriate; ♂ and ♀ sternite II with all setae situated near posterior margin (Figs 19 , 20 ); most setae of male sternite III clustered near posterior margin (Fig. 19 ). Spiracles with helix. Anal plates (tergite XII and sternite XII) situated between tergite XI and sternite XI, and surrounded by desclerotized region of tergite XI and sternite XI; sternite XI with 26 (♂), 22 (♀) small lyrifissures. Pleural membrane finely wrinkled-plicate; without any setae.

Genitalia: male: very similar to that described for L. laceyi Muchmore, 1981 by Muchmore (1981). Female with 1 pair of lateral cribriform plates and 2 median cribriform plates, one of which is larger than the other (Fig. 21 ); spermathecae absent.

Dimensions (mm): Male: holotype, with 1 other male in parentheses (when measured): Body length (excluding chelicerae) 2.37 (2.25). Pedipalp: trochanter 0.370/0.200, femur 0.895/0.195 (0.845/0.185), patella 0.725/0.225 (0.650/0.210), chela (with pedicel) 1.200/0.275 (1.225/0.245), chela (without pedicel) length 1.200 (1.170), chelal hand (without pedicel) length 0.575 (0.570), movable finger length 0.550 (0.600). Carapace 0.640/0.850 (0.580/0.800), anterior eye diameter 0.055, posterior eye diameter 0.050. Leg IV: femur + patella 0.730/0.140, tibia 0.530/0.100, metatarsus 0.265/0.065, tarsus 0.250/0.055.

Female: paratype, with 3 other females in parentheses (when measured): Body length (excluding chelicerae) 2.51 (2.51-2.74). Pedipalp: trochanter 0.375/0.210, femur 0.895/0.205 (0.895-0.990/0.205-0.220), patella 0.755/0.235 (0.765-0.795/0.230-0.240), chela (with pedicel) 1.205/0.315 (1.190-1.255/0.295-0.325), chela (without pedicel) length 1.135 (1.125-1.255), chelal hand (without pedicel) length 0.575 (0.550-0.595), movable finger length 0.565 (0.565-0.575). Carapace 0.640/0.815 (0.645-0.655/0.805-0.815), anterior eye diameter 0.065, posterior eye diameter 0.060. Leg IV: femur + patella 0.745/0.155, tibia 0.530/0.095, metatarsus 0.270/0.065, tarsus 0.250/0.055.

Etymology.

The species epithet is a noun taken from the type locality of Boulder County, Colorado. Mallory Cave is situated on City of Boulder, Open Space and Mountain Parks property.

Figures

Figure 6. Larca boulderica sp. nov., in situ in Mallory Cave.

Figures 7 - 9. Larca boulderica sp. nov., paratype female (DMNS): 7 body, dorsal 8 body, ventral 9 cephalothorax, dorsal. Scale bars: 0.5 mm.

Figures 10 - 18. Larca boulderica sp. nov., holotype male and paratype female (DMNS): 10 carapace, dorsal, male 11 left pair of eyes, dorsal, male 12 right pedipalp, dorsal, male 13 right pedipalp, dorsal, male 14 left chela, retrolateral, male 15 left chela, retrolateral, female 16 left galea, dorsal, male 17 left galea, ventral, female 18 left leg IV, retrolateral, male. Scale bars: 0.5 mm (12, 13); 0.25 mm (10, 14, 15, 18); 0.1 mm (11); 0.05 mm (16, 17).

Figures 19 - 21. Larca boulderica sp. nov., holotype male and paratype female (DMNS): 19 genital sternites, ventral, male 20 genital sternites, ventral, female 21 genitalia, ventral, female. Scale bars: 0.2 mm.