Pseudochthonius species

Prado, Guilherme C. & Ferreira, Rodrigo L., 2023, Three new troglobitic species of Pseudochthonius Balzan, 1892 (Pseudoscorpiones, Chthoniidae) from northeastern Brazil, Zootaxa 5249 (1), pp. 92-110 : 108

Key to Brazilian Pseudochthonius species

1 Eyes absent.......................................................................................... 2

- Presence of a pair of eyes or eyespots in one or both gender.................................................... 3

2 Trichobothrium ist closer to est than to esb.................................. Pseudochthonius koinopoliteia sp. nov.

- Trichobothrium ist closer to esb than to est or ist halfway from esb and est....................................... 4

3 Chelal fixed finger with heterodonty (off-set saw-like)....................................................... 5

- Chelal fixed finger without heterodonty (simple row of teeth).................................................. 6

4 Body length with at least 2.0 mm.............................................. Pseudochthonius diamachi sp. nov.

- Body length less than 2.0 mm........................................................................... 7

5 Carapace 1.0–1.1 times longer than wide, chelal fixed finger teeth with microteeth on 15 th and 29 th teeth, endemic to Gruta do Vandercir, Serra do Ramalho, BA.................................................... Pseudochthonius ramalho

- Carapace> 1.1 times longer than wide, chelal fixed finger without microteeth..................................... 8

6 Chelal morphology typically sigmoid with a small apodeme, with flattened teeth on movable finger................................................................................. Pseudochthonius homodentatus Chamberlin, 1929

- Chelal morphology highly straight, large and well-developed apodeme, bearing rounded basal teeth in both fingers.................................................................................... Pseudochthonius orthodactylus

7 Epistome acute and smooth, endemic to Lapa Zé de Sidinei, Presidente Olegário, MG................................................................................................ Pseudochthonius olegario Schimonsky, 2022

- Epistome acute and highly serrated....................................................................... 9

8 Chelal fixed finger bearing more than 26 teeth............................................................. 10

- Chelal fixed finger bearing less than 26 teeth.............................................................. 11

9 Heterodonty on fixed chelal finger present only after the 10 th teeth from basal to distal one, trichobothrium et proximad to it and distad to dx ................................................................... Pseudochthonius pali sp. nov.

- Heterodonty present on almost the whole dentition of chelal fixed finger, endemic to Gruta dos Olhos d’Água, Itacarambi, Minas Gerais .................................................................... Pseudochthonius biseriatus

10 Epistome small and highly dentate, ist–est/ist–esb ratio near 2.0, chelal movable finger with less teeth than chelal fixed finger (24 on movable and 35 on fixed) where the latter presents a distal isolated tooth...... Pseudochthonius tuxeni Mahnert, 1979

- Chelal movable finger with more teeth than chelal fixed finger, with occurrence in S„o Paulo state.................... 12

11 Chelal movable finger with heterodonty dentition........................ Pseudochthonius gracilimanus Mahnert, 2001

- Chelal movable finger partially or fully retroprojected homodont teeth.......................................... 13

12 Epistome acute and prominent, with the anterior margin serrated from the epistome ranging to ame carapacal setae, coxa I and coxae II bearing two coxal spines..................................................... Pseudochthonius strinatii

- Epistome acute and highly dentate only in female, lateral portion of the anterior margin of the carapace wrinkled, presence of six setae on the last seven tergite plates (from anterior to posterior), ist–est/ist–esb ratio of 2.5............................................................................................ Pseudochthonius brasiliensis Beier, 1970

13 Movable finger with 40 or more teeth, distally retrorse and basally rounded teeth... Pseudochthonius ricardoi Mahnert, 2001

- Movable finger with about 30 retrorse tee................................ Pseudochthonius heterodentatus Hoff, 1946