Pachychernes zehorum Muchmore, 1997

Marimon, Karla, Villarreal-Blanco, Eduardo, Romero-Ortiz, Catalina & Gutierrez, Luis C., 2021, A new species and new records of Pachychernes Beier, 1932 from Colombia (Pseudoscorpiones, Chernetidae), Zootaxa 4999 (4), pp. 363-376 : 369-375

Pachychernes zehorum Muchmore, 1997

Figs. 4A–D , 5A–G , 6A–G , 7B

Pachychernes zehorum Muchmore, 1997: 19–21 , figs 1–4; Ceballos, 2004: 429; Villegas-Guzman, 2006: 133; Harvey 2013.

Diagnosis. This species differs from all other Pachychernes species by the first leg of the males, which not only has long and short modified setae on the tibia, but also a conspicuous depression on the dorsal side of the tarsus ( Muchmore 1997) ( Fig. 4 ).

Examined material. COLOMBIA, Bolívar , Municipio de San Jacinto , La Flecha, Finca Amanecer Gaitero (9°51’9.74” N; 75°10’32.32” W), 250 m, 4 ♀ (ICN-Aps-835) and 2 ♂ (IAvH-I-4079), 11–12.IX.2019, K. Marimon and E. Villarreal leg.

Description (adults): Colour: carapace red-brown with a lighter tone below the transversal furrow. Tergites light brown, pedipalps reddish-brown. Legs light yellow-brown toned.

Carapace: heavily granulated, subrectangular with broad posterior margin; 0.78–0.93 (♂) 0.86–1.13 (♀) × longer than broad, with two eye spots; anterior margin with 8 setae (♂) 7 setae (♀), posterior margin with 6 setae (♂, ♀).

Chelicera: 2.13–2.54 (♂), 1.44–2.40 (♀) × longer than broad; with 5 setae on hand and 1 distal seta on movable finger, es, is and ls acuminate, bs and sbs dentate; galea with 5 rami; rallum with 3 blades, posterior blade with several ramifications while others smooth; serrula exterior with 24 blades (♂, ♀); lamina exterior present ( Figs. 5 , 6 ).

Pedipalp: with robust trochanter, femur, patella and granulated hand with several denticulated setae and chelal fingers smooth; trochanter 1.30–1.36 (♂), 1.27–1.39 (♀), femur 2.70–2.92 (♂), 2.10–2.42 (♀), patella 2.38–2.50 (♂), 2.12–2.37 (♀), chela (with pedicel) 2.81–3.05 (♂), 2.61–2.89 (♀), chela (without pedicel) 2.63–2.86 (♂), 2.61–2.89 (♀), hand 1.53–1.63 (♂), 1.54–1.68 (♀) × longer than broad, movable finger 0.76–0.77 (♂), 0.59–0.86 (♀) × longer than hand. All marginal teeth rounded except the terminal ones, which are pointed, external accessory teeth present on both fingers, with 6 (♂), 7 (♀) on the movable finger and 9 (♂), 11(♀) on the fixed finger. Fixed chelal finger with 8 trichobothria, movable chelal finger with 4 trichobothria: eb, esb, est and et slightly L-shaped, eb and esb situated basally, est located medially and at an equal distance from esb and et, which is located terminally; ib and ist basally located, with ist, eb and esb aligned, isb located in a medial position and closer to it and ib; b, sb and st placed in the first half of the movable finger with b and sb much closer to each other than to st, t located subterminally, midway from st and tip of finger. Venom apparatus present only in movable chelal finger with nodus ramosus located next to t ( Figs. 5 , 6 ).

Coxal region: maxillae smooth except for the antero-lateral region, coxae smooth, manducatory process triangular in shape; regarding the setae, these individuals have one apical, one subapical and one sub oral while there are 25 additional setae (♂). Maxillary lyrifissure rounded and placed submedially. Chaetotaxy of coxae I–IV in ♂: 14: 12: 16: 44; ♀: 13: 11: 15: 36.

Legs: leg I sexually dimorphic, with males having a tibia with a large number of setae plus a distinct depression on the surface of the tarsus while that of the females are chernetid in structure. Femur + patella of leg IV 2.67–2.77 (♂), 3.56–4.17 (♀) × longer than broad, as well as tibia and tarsus 3.79–4.11 (♂), 3.56–4.17 (♀) and 4.27–4.64 (♂), 3.89–4.67 (♀) × longer than broad, respectively. Tarsi III and IV with tactile seta, located subbasally, TS= 0.18 in both males and females approximately. Claws and arolium are equal in length.

Abdomen: tergites I–X and sternites I–X with a clear medial suture line. Tergal chaetotaxy: ♂, 8: 7: 9: 8: 11: 13: 12: 12: 13: 12: 11: 2; ♀, 10: 10: 10: 10: 12: 12: 12: 13: 14: 13: 11: 2, all setae clavate. Sternal chaetotaxy: ♂, 47, (3) 16 (3): (1) 8 (1): 17: 19: 19: 23: 20: 17: 15: 2; ♀, 38: (2) 8 (2): (1) 9 (1): 20: 19: 18: 18: 18: 17: 16: 4. Spiracle with helix. Pleural membrane striated and without setae.

Genitalia: spermatheca somewhat H-shaped, with four lobes, the anterior ones, oval in shape while the posterior ones have a tubular form with several cribriform plates along the ducts ( Fig. 7B ). Male genitalia consisting of 47 setae on the anterior operculum and 16 on the posterior operculum.

Dimensions (mm): males, followed by females in parentheses: Body length 3.05–3.10 (2.44–3.30). Carapace 0.86–1.09/1.10–1.17 (0.81–1.05/0.82–1.22) Chelicera 0.32–0.33/0.13–0.15 (0.23–0.31/0.10–0.16), movable finger length 0.23–0.28 (0.20–0.25. Pedipalps: trochanter 0.48–0.49/0.36–0.37 (0.33–0.46/0.26–0.36), femur 1.10–1.14/0.37–0.39 (0.61–0.87/0.29–0.39), patella 1.00–1.15/0.42–0.46 (0.72–0.97/0.34–0.45), chela (with pedicel) 1.74/0.57–0.62 (1.39–1.89/0.46–0.62), chela (without pedicel) 1.63 (1.31–1.79), hand (without pedicel) length 0.93–0.95 (0.71–1.00), movable finger length 0.72 (0.57–0.85). Leg IV: femur 0.35–0.37/0.27–0.30 (0.26– 0.32/0.19–0.25), patella 0.77–0.8/0.35–0.36 (0.51–0.73/0.20–0.33), tibia 0.72–0.78/0.19 (0.50–0.72/0.12–0.18) tarsus 0.47–0.51/0.11 (0.35–0.49/0.09–0.11).

Distribution and habitat. This species has been previously recorded from Mexico and Panama ( Muchmore 1997; Ceballos 2004; Villegas-Guzman 2006), and according to Muchmore (1997) it is probably widespread through Central America. Here we expand the distribution to South America, with a population found in the Montes de María in northern Colombia. The new records demonstrate that this species is not necessarily restricted to environments such as rain forest (type locality) but also occurs in tropical dry forest ( Figs. 8 , 9 ).

Figures

FIGURE 4. Pachychernes zehorum Muchmore, 1997. A–B. Male habitus (IAvH-I-4079). A, Dorsal view. B. Ventral view. C–D. Female habitus (ICN-Aps-835). C. Dorsal view. D. Ventral view. Scale bar: A–D:1mm.

FIGURE 5. Pachychernes zehorum Muchmore, 1997. Male. A. Left pedipalp. B. Left leg IV. C. Left chelicera. D. Left leg I. E. Rallum. F. Left chela, lateral view. G. Galea. Scale bars: A–B, D, F: 0.3 mm; C: 0.1 mm; E, G: 0.05 mm.

FIGURE 6. Pachychernes zehorum Muchmore, 1997. Female. A. Left pedipalp. B. Left leg IV. C. Left chelicera. D. Left leg I. E. Left chela, lateral view. F. Galea G. Rallum. Scale bars: A–B, D–E: 0.3 mm; C: 0.1 mm, F–G: 0.05 mm.

FIGURE 7. Schematic representation. of spermathecae. A. Pachychernes florezi sp. n. B. Pachychernes zehorum.

FIGURE 8. A–B. Type locality of Pachychernes florezi sp. n. and habitat of P. zehorum. San Jacinto, Bolívar.

FIGURE 9. Known distribution of extant species of Pachychernes.