Pseudochthonius pali, Prado & Ferreira, 2023

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 : 103-107

Pseudochthonius pali sp. nov.

Material examined. Holotype male (ISLA 100992), preserved in ethanol: Brazil, Serra do Ramalho, Bahia, Gruna do Google Cave (13º37’41.93”S, 43º48’49.04”W), 22 September 2021, leg. R. L Ferreira . Allotype female ( ISLA 100993), same data as holotype .

Etymology. Páli (from Greek “πάλη”) can be translated as “fight, battle”, and represents the recent fight of the Brazilian speleology community in favor of cave preservation and against the recent presidential decree that allowed the destruction of maximum relevance caves in Brazil. This noun should be treated as noun in apposition.

Diagnosis. Differing from the other members of the genus by the following combination of characters: Absence of eyes or eyespots; carapace with a strong posterior constriction; ist–est/ist–esb trichobothria ratio of 2.46 (2.77); chelal fixed finger with 34 (39) acute teeth with heterodonty starting from the 10 th proximal tooth, chelal movable finger with 36 (38) small and retrorse teeth; cheliceral fixed finger with 9 (11) spaced and regular teeth, movable finger with 9 (12) teeth, with no constrictions or distal isolated teeth; presence of two and four setae on the first and second tergites, respectively; trichobothria est, it and et grouped; body length of 1.33 (1.70) mm; chela 5.9 to 6.5 times as long as broad.

Description ( Figs 9C–D , 11B ). Body pale yellowish, very translucent; chelicerae slightly orange, abdomen beige. Vestitural setae thin and anteriorly projected on prosoma and posteriorly projected on opisthosoma.

Carapace ( Fig. 8C ). 1.09 (1.05) times longer than broad, strongly constricted posteriorly showing a difference between ocular width and posterior width of 0.11 (0.15) mm ( Fig. 8C ); anterior margin all serrated; no eyes or eyespots; epistome strongly dentate and saw-like (ranging to lateral setae); posterior margin of carapace smooth; chaetotaxy 4+2: 4: 4: 2: 2 (18).

Chelicera ( Figs 2A–B , 8B ). Hand with 5 setae; movable finger with 1 subdistal seta and fixed finger; galea present as a smooth hump; fixed finger with 9 (11) well-defined acute teeth; movable finger with 9 (12) well-defined acute teeth; rallum with 7 blades, serrula exterior with 14 blades, serrula interior with 10 blades.

Tergites. Not divided; surface smooth; chaetotaxy uniseriate, I–XI 2: 4: 4: 4: 6: 6: 6: 4: 6: 2: 2 + 2 sensory setae. Anal operculum without dorsal setae. Pleural membranes striate.

Coxae ( Figs 8A–G ). Manducatory process with two apical setae, lateral ones slightly smaller than medial; rest of palp coxae with 3 setae arranged in a triangle; delicate lamellae outlined by 9 small spines. Pedal ( Fig. 8A ): coxal spines plumose (highly dentated), arranged in a single transverse row in coxae I (3–5) and II (5–6) (( Fig. 8G ), chaetotaxy: I 4+1, II 4 (5), III 7–8, IV 8 (9); intercoxal tubercle absent.

Genital operculum of female: 9 setae distributed in three horizontal rows: 2: 3: 4, genital opening not clearly bifurcated.

Genital operculum of male ( Fig. 8H ): anterior margin of operculum with 8 discal setae distributed marginally; six valvular setae on each side of the opening; 4 surrounding setae and 3-2(5) microlateral setae ( Fig. 8H ).

Sternites: chaetotaxy IV‒XI: 10: 8: 8: 8: 8: 6: 4: 2. Anal operculum with two ventral setae.

Palp ( Figs 8F, I ). Trochanter 1.67 times longer than wide, femur 5.65 (5.71) times longer than wide, patella 2.22 (2.23) times longer than wide. Femoral chaetotaxy 5: 6: 3: 5: 2. Trichobothrial pattern: ib and isb located at the half portion of the hand proximad to a tiny hump ( Fig. 8I ), adjacent to each other, eb proximad to esb, ist distad to esb, it between est and et, et proximad from dx and distad to it; ist closer to esb than to est (ratio distance ist-est/ist-esb = 2.46 [2.77]). Fixed finger slightly sigmoid; movable finger slightly curved ( Fig. 8I ). Chelal fixed finger with 34 (39) acute, triangular, and widely spaced teeth, with heterodonty starting from the 10 th teeth. Movable finger with 36 (38) small and projected backwards teeth.

Leg IV ( Fig. 8E ). Arolia slightly smaller than claws.

Measurements (length/width or depth in mm and ratios in parenthesis calculated by using three significant digits): Male holotype (female paratypes in brackets). Body length 1.33 [1.70]. Carapace 0.42/0.39 (1.1) [0.49/0.46 (1.1)]. Palps: trochanter 0.20/0.12 (1.7) [0.22/0.13 (1.7)], femur 0.63/0.11 (5.7) [0.74/0.13 (5.7)], patella 0.28/0.13 (2.2) [0.31/0.14 (2.2)], chela 0.87/0.13 (6.5) [0.98/0.17 (5.9)], movable finger length 0.58 [0.64]. Leg I: trochanter 0.14/0.10 (1.4) [0.15/0.11 (1.4)], femur 0.34/0.07 (5.2) [0.39/0.07 (5.5)], patella 0.18/0.05 (3.6) [0.2/0.06 (3.6)], femur/patella 1.9 [2.0], tibia 0.19/0.04 (4.7) [0.22/0.04 (5.0)], tarsus 0.35/0.03 (10.2) [0.41/0.04 (10.2)]. Leg IV: Trochanter: 0.12/0.11 (1.2) [0.16/0.12 (1.3)], femur + patella 0.5/0.19 (2.7) [0.6/0.21 (2.8)], tibia 0.31/0.08 (3.9) [0.37/0.09 (4.2)], basitarsus 0.17/0.06 (2.9) [0.22/0.06 (3.6)], telotarsus 0.36/0.04 (9.9) [0.42/0.04 (10.6)].

Ecological Remarks. Specimens of Pseudochthonius pali sp. nov. were found in the Gruna do Google cave, located in Serra do Ramalho municipality, southwestern Bahia state, Brazil. This cave has 1.230 meters of horizontal projection, with a single entrance, which represents a sinkhole ( Fig. 9A ). There is an intermittent drainage in the external landscape, which drains to the cave entrance. Hence, a huge amount of sediment and organic matter are seasonally carried to the cave demanding periodic debris removal in order to access inner conduits. The conduits are predominantly wide, and moistened sediments cover the floor ( Fig. 9B ). The majority of the main conduit is seasonally flooded, and the main organic resource observed is plant-decaying material. The specimens of P. pali sp. nov. were found walking freely on the floor ( Figs 9C–D ) situated in an upper chamber located laterally in relation to the main cave conduit, at about 600 meters from the entrance.

This cave has only been visited by speleologists since its discovery, due to the difficult access to its inner portions, which leads to a quite preserved interior. Nonetheless, since it receives a huge contribution of external sediments brought by water, an apparent silting was observed along the main conduit of the cave. However, contrary to the observations for the other two caves herein described, the external landscape surrounding the cave (especially upstream) is slightly modified, and a secondary forest predominates along the area.

Figures

FIGURE 2. SEM images of the new species A P. pali sp. nov. right chelicera of the paratype, dorsal view B P. pali sp. nov. left chelicera of the paratype, ventral view C P. diamachi sp. nov. coxae region of the paratype D P. koinopoliteia sp. nov. right chelicera of the paratype, dorsal view E P. koinopoliteia sp. nov. left chelicera of the paratype, ventral view F P. diamachi sp. nov. detail of coxal spines of the paratype. Scale bars: 0.2 mm (A–B); 0.4 mm (C); 0.1 mm (D–E); 0.05 mm (F).

FIGURE 8. Pseudochthonius pali sp. nov. A Male holotype palp and pedal coxae B Left chelicera of male holotype, antiaxial view C Carapace of male holotype D Leg I of male holotype E Leg IV of male holotype F Pedipalp femur of male holotype, dorsal view G Detail of coxae I and II, showing arrangement of coxal spines H Male holotype genitalia I Right Chela of holotype, showing trichobothrial pattern, antiaxial view. Scale bars: 0.2 mm (A–B); 0.25 mm (C–F); 0.1 mm (G–H); 0.5 mm (I).

FIGURE 9. Pseudochthonius pali sp. nov. A Google cave region. Satellite view B Google cave general aspect C Live male holotype D Live female paratype.

FIGURE 11. New species habitus. A Pseudochthonius diamachi sp. nov. paratype habitus. B Pseudochthonius pali sp. nov. paratype habitus C Pseudochthonius koinopoliteia sp. nov. holotype habitus. Scale bars: 2.0 mm (A); 1.0 mm (B–C).