Pseudochthonius biseriatus Mahnert, 2001

Material examined. 2 males, Pernambuco, Brazil: Furna do Morcego cave, 8°34’14.1”S; 37°22’55.6”W, 556 m a.s.l., 09-V-2019; Catimbau National Park, E. Barbier leg. (LECA; Ps-SCR008) .

Diagnosis. According to Mahnert (2001) Pseudochthonius biseriatus, it can be easily distinguished from the other species of the genus by the carapace reticule, as long as broad, absent eyes, anterior margin with a prominent dentate epistome, 16 strong setae, one preocular seta present on each side (Mahnert 2001; Fig. 13); Chelicerae with five setae, fixed finger with 9–11 acute teeth, movable finger with 8–10 teeth, absent spinneret tooth-like in male, serrula exterior with 20 blades, rallum nine setae, first only shorts dentate (see Mahnert 2001; Fig. 14); Tergites whitish-yellow, tergites III–IV with round medial spots, chaetotaxy: 2: 2: 4: 4-6: 6: 6: 6: 6: 4: 4(2ST): 2; Pedipalps, femur 6.4–6.6×, patella 2.2–2.5×, hand 2.3–2.4×, chela 7.5–8.0×, finger 2.3×, fixed finger with 37–41 pointed teeth arranged like offset saw teeth and therefore giving the impression of heterodonty, trichobothrium ist much near to esb than to est, and one sensillum distal to sb on movable finger (see Mahnert 2001; Figs. 15–16); Leg I: femur 6.1–6.2×, 4.2–4.5×, tibia 4.9–5.3×, tarsus 10.4–11.3×; Leg IV: femur+patella 3.1–3.4×, tibia 5.0–5.2×, metatarsus 3.5–3.8×, tarsus 10.6–11.9× (one basal tactile seta).

Remarks. Measurements and proportion of pedipalps, distribution of trichobothria, and some other taxonomic characters correspond to the description of P. biseriatus from Minas Gerais, Brazil (Mahnert 2001; Figs. 13–16). The specimens of the cave from Pernambuco (Brazil) slightly differ from the other specimens in the body length (1.649 –1.656), smaller than those described by Mahnert (2001), similarly in the number of teeth on the fingers of the chela, 35 teeth on the fixed finger and 31 on the movable finger, however, these differences can be attributed to intraspecific variations by the geographical distribution of the species, since all the diagnostic characters correspond to the species P. biseriatus .

Measurements (mm). Body length: 1.649 –1.656. Carapace: 0.523–0.526/0.438–0.456. Pedipalps: femur: 0.426–0.459/0.114–0.116, patella 0.237–0.241/0.101–0.103, chela: 0.792–0.796/0.157–0.159, movable finger: 0.513 / 0.030. Chelicera: 0.149 / 0.090, movable finger length: 0.125. Leg I: femur: 0.461–0.463/0.070–0.080, patella: 0.273–0.281/0.060–0.080, tibia: 0.251–0.273/0.050–0.070, tarsus: 0.477–0.479/0.050–0.060. Leg IV: femur+patella: 0.689–0.690/0.213–0.232, tibia: 0.441–0–443/ 0.070 –0.090, metatarsus: 0.25–0.27/ 0.070 –0.090, tarsus: 0.493–0.495/0.050–0.070.

Distribution: Brazil (Harvey 2013; World Pseudoscorpiones Catalog 2022).