Pseudochthonius, Balzan, 1892

Assis, Leonardo de, Schimonsky, Diego Monteiro von, Gallão, Jonas Eduardo & Bichuette, Maria Elina, 2023, Contribution to the knowledge of Brazilian troglobitic Pseudoscorpiones (Arachnida): description of Pseudochthonius lubueno sp. nov. (Chthoniidae) from Serra do Ramalho karst area, state of Bahia, Brazil, Zoologia (e 22048) 40, pp. 1-11 : 6-8

Key to cave-dwelling Pseudochthonius

1. Eyeless, eyespots present; trichobothrium ist at least 3×further away from est than from esb (ratio ist-est/ ist-esb ≥ 3.0)..................................................................... 2

1’. Eyeless, eyespots absent; trichobothrium ist less than 2.8× further away from est than from esb (ratio ist-est/ ist-esb ≤ 2.8)..................................................................... 3

2. Ratio ist-est/ist-esb = 4.71; chelal length = 0.82–0.90; pedipalpal patella larger (4.1), pedipalpal femur smaller (4.1); endemic to Gruna do Vandercir cave, Bahia, Brazil...................................................................... .......... P. ramalho Assis, Schimonsky & Bichuette, 2021

2’. Ratio ist-est/ist-esb = 3.0; chelal length = 0.82–1.06; pedipalpal patella smaller (2.0), pedipalpal femur larger (5.3–6.1); occurrence in São Paulo, Minas Gerais and Paraná, Brazil................ P. strinatii Beier, 1969

3. Tergite I with 2 setae and tergite II with 4 setae ........ 4

3’. Setae configuration other than the step above .......... 5

4. Ratio ist-est/ist-esb = 1.02–1.11; coxa II with 4 coxal spines; chelal length = 1.43–1.59 pedipalpal femur larger (6.8)............. P. diamachi Prado & Ferreira, 2023

4’. Ratio ist-est/ist-esb = 2.46–2.77; coxa II with 5-6 coxal spines; chelal length = 0.87–0.98, pedipalpal femur smaller (5.7) .................... P. pali Prado & Ferreira, 2023

5. Tergite I and II each with 2 setae ................................. 6

5’. Tergite I and II each with 4 setae ................................. 7

6. Ratio ist-est/ist-esb = 1.78–2.10; chelal length = 1.24– 1.39; pedipalpal femur smaller (6.3–6.6); endemic to Olhos d’Água cave, Minas Gerais, Brazil........................ .............................................. P. biseriatus Mahnert, 2001

6’. Ratio ist-est/ist-esb = 0.68–0.85; chelal length = 1.04– 1.16, pedipalpal femur larger (6.8) ................................. ........................... P. koinopoliteia Prado & Ferreira, 2023

7. Carapace with 20 setae, including four on posterior margin; coxal spines numerous and varied on coxae I and II and including one small spine on coxa III; ist-est/ist-esb = 1.0; chelal length= 1.73; occurrence at Cueva del Cenote Xtolok, Chichkn Itza, Yucatan, Mexico.. ......................................... P. troglobius Muchmore, 1986

7’. Carapace with 18 setae, including two on posterior margin; coxal spines present on coxae I and II, but absent from coxa III; trichobothrium ist closer to esb than to est (2.40 ≤ ist-est/ist- esb≤2.49)......................... 8

8. Rallum with five blades; ist-est/ist-esb = 1.9; chelal length = 0.53–0.76; coxa I with 2 spines, coxa II with 4–5 spines; pedipalpal fixed finger with 30–32 teeth, movable finger with 29–30 teeth; endemic to Gruna da Altina cave, Bahia, Brazil............. P. lubueno sp. nov.

8’. Rallum with six or more blades; 2.40 ≤ ist-est/ist-esb ≤ 2.49................................................................................... 9

9. Coxa I with 2–3 spines, coxa II with 3–4 spines; ist-est/ist-esb = 2.40; chelal length = 0.7; rallum with six blades; occurrence at the cave of Quadirikiri, Aruba... ..................... P. arubensis Wagenaar-Hummelinck, 1948

9’. Coxa I with 4 spines, coxa II with 5 spines; ist-est/ist-esb = 2.49; chelal length = 0.89–0.99; rallum with seven blades; occurrence at Zé de Sidinei cave, Minas Gerais, Brazil................................. P. olegario Schimonsky, 2022