Pseudochthonius limettioides, Schimonsky, 2024

Schimonsky, Diego Monteiro Von, 2024, Two new cavernicolous species of Pseudochthonius Balzan, 1892 (Pseudoscorpiones, Chthoniidae) from Lagoa Santa karst, Minas Gerais, Brazil, Zootaxa 5433 (1), pp. 107-120 : 111-112

Pseudochthonius limettioides sp. nov.

Fig. 3–4

Type material. Holotype: 1 ♂ ( LES22817 ), BRAZIL: Minas Gerais, Cerrado province, Limeira massif karst area, Prudente de Morais , 01L cave; S19°26'32.5" W44° 6'24.3"; 04.iii.2019; Zampaulo, R. A.; Reis, A. S. leg. Allotype: 1 ♀ ( LES22817 ), together with the holotype .

Paratypes: 1 ♂ ( LES22817 )together with the holotype ; 1 ♂ ( LES22813 ), 40L cave; S19°26'24.9" W44°06'20.4"; 08.iii.2019; Zampaulo, R. A.; Reis, A. S. leg ; 1 ♀ ( LES22798 ), 51L cave; S19°26'23.5" W44°06'13.1"; 09.iii.2019; Zampaulo, R. A.; Reis, A. S. leg ; 1 ♀ ( LES22805 ), ES17 cave; S19°26'45.1" W44°06'10.2"; 08.iii.2019; Zampaulo, R. A.; Reis, A. S. leg ; 1 ♀, 1 ♂ ( MZSP78847 ), 48L cave; S19º26'21.8'' W44º06'18.2''; 05.xii.2021; Zampaulo, R. A.; Reis, A. S. leg ; 1 ♂ ( MZSP78848 ), 77L cave; S19º26'20'' W44º05'39''; 05.xii.2021; Zampaulo, R. A.; Reis, A. S. leg.

Other studied material: 1 ♂, 1 ♀ ( LES22814 ), ES05 cave; S19º26'29.6'' W44º06'24.6"; 01.iii.2019; Zampaulo, R. A.; Reis, A. S. leg ; 2 ♀, 1 ♂ ( LES 22820 ), ES13 cave; S19º26'29.44'' W44º06'25.6''; 06.iii.2019; Zampaulo, R. A.; Reis, A. S. leg ; 1 ♀ ( LES22828 ), ES03 cave; S19º26'29.44'' W44º06'25.6''; 01.iii.2019; Zampaulo, R. A.; Reis, A. S. leg ; 1 ♀ ( ISLA 48243), 02L cave; S19º26'32.5'' W44º06'22.7''; 20.xi.2017; Bondezan, F. leg.

Etymology. The epithet limettioides is in allusion to the tree known as Limeira in Portuguese which is the name of the karst massif where the new species occurs.

Diagnosis. Pseudochthonius limettioides sp. nov. can be identified by the absence of eyes or eyespots in males, one pair of eyespots in females, epistome prominent and dentate, appearing like a crown, cheliceral serrula exterior with 16 lamellae and interior with 14 lamellae and coxa II with some small protuberances appearing like a grater.

Description (adult male and female): Body: Specimens in 70% ethanol are yellowish-brown, in carapace, chelicera and pedipalps. The integument is weakly sclerotized and depigmented; tergites III–V with dark median mark ( Fig. 3 ). Live specimen with most of body light yellow, and carapace, chelicera and pedipalps pale reddishbrown and a bit translucent. Male is smaller than female.

Carapace ( Fig.4A–B ): epistome prominent, dentate, crown-like in appearance; eyeless (eyespot present in females); slightly constricted posteriorly; chaetotaxy 6:4:4:2:2 (18), one pair of preocular microsetae; 2 lyrifissures anteriorly, 2 medially and 2 posteriorly.

Chelicera ( Fig.4C–D ): 3 lyrifissures; 5 setae on hand, with one seta (dt) on basal position of fixed finger and one seta (gl) close to basal position of movable finger, with two lateral microsetae (vb and vt), with two seta on central position of the hand (it and db); all setae acuminate; fixed finger with 7 teeth proximally reduced in size; movable finger with 6 teeth proximally reduced in size with subapical isolated tooth (di); serrula exterior with 14 blades; serrula interior with 16 blades; rallum with 7 pectinate blades. Movable finger of ♀ with a subapical small galea.

Pedipalp ( Figs.3E–G ): 3.8 (♂)/3.4 (♀) × longer than patella; movable finger 1.8 (♂)/1.6 (♀) × longer than hand. Fixed chelal finger long and strongly sigmoid in distal half. Fixed finger with 34 distinctly separated acute teeth. Movable finger with 35 flattened and separated teeth. Trichobothria: ib and isb situated close to each other sub–medially in dorsal region of chelal hand; eb closer to esb than to ist, forming a straight oblique row at base of fixed chelal finger; ist three times closer to esb than to est (ratio ist-est/ist-esb = 3.0); et near tip of fixed finger; dx at end of the fixed finger; t closer to st and situated at same level as est, st closer to t, than sb to b.

Coxae ( Fig.3H ): manducatory process distally acute, with 2 setae; pedipalpal coxae with 3 setae; coxa I with 5 setae and 2 coxal spines; coxa II with 5 setae and 4–5 coxal spines decreasing in size distally, and with some small protuberances appearing like a grater; coxa III with 7 setae; coxa IV with 8 setae; intercoxal tubercle absent. Coxal spines softly serrated, almost smooth.

Abdomen: chaetotaxy of tergites I–XI: 4: 4: 4: 4: 6: 6: 6: 6: 6: 5: 3. Chaetotaxy of sternites III–XI: (♂) 8: 3(14)3: 8: 8: 8: 8: 6: 5: 2 (♀) 12: 12: 8: 8: 8: 8: 6: 5: 2; anal cone with 0/2 setae. Genital area: ( Fig.3I ): anterior genital operculum with 8(♂)/12(♀) marginal and discal setae, genital opening slit-like and triangular in males, with 7 marginal setae on each side; posterior operculum with 12 setae in females.

Legs: leg I: femur 5.8 (♂)/6.4 (♀) times longer than deep and 1.7 (♂)/1.5 (♀) longer than patella; patella 3.4 (♂)/4.2 (♀) times longer than deep; tibia 4.0 (♂)/4.5 (♀) times longer than deep; tarsus 9.6 (♂)/11.6 (♀) times longer than deep; tarsus 1.8 (♂)/1.9 (♀) times longer than tibia. Leg IV: femur + patella 2.3 (♂)/2.7 (♀) times longer than deep; tibia 4.1 (♂)/4.0 (♀) times longer than deep; basitarsus 2.8 (♂)/3.6 (♀) times longer than deep; telotarsus 10.3 (♂)/ 12.3(♀) times longer than deep.

Measurements and ratios: see Table 1 .

Remarks. The species resembles other Brazilian species of Pseudochthonius that lack eyes but have a pair of eyespots, P. ramalho and P. strinatii , but differs from them as follows: P. limettioides sp. nov. has rallum with 7 blades (8 in P. strinatii ), absence of microdenticles on fixed pedipalpal finger (2 present in P. ramalho ), and ratio ist-est/ist-esb = 3.0 (4.71 in P. ramalho ). Pseudochthonius limettioides sp. nov. differs from other cave-dwelling species of the genus by its ratio ist-est/ist-esb (0.68–0.85 in P. koinopoliteia , 1.0 in P. troglobius , 1.02 in P. diamachi , 1.22 in P. gracilimanus Mahnert, 2001 , 1.72 in P. galapagensis Beier, 1977 , 1.78–2.10 in P. biseriatus , 1.90 in P. lubueno 1.98 in P. ricardoi Mahnert, 2001 , 2.4 in P. arubensis , 2.46–2.77 in P. pali , 2.49 in P. olegario , 4.71 in P. ramalho and 2.0 in P. lundi sp. nov).

Distribution and habitat. The type locality of Pseudochthonius limettioides sp. nov. (01L Cave) is located in the Limeira Massif, near the dissolution dolmen, and is seasonally flooded by the rainwater that feeds it. Speleometrically, this cave has 175 m of horizontal projection, 3.5 m of unevenness, 416.9 m ² of surface area and 1,254.2 m ³ of volume. Morphologically it has a meandering pattern, with soil composed of clay sediment and chemical deposits represented by a variety of speleothems ( CANIE 2022, Robson de Almeida Zampaulo personal communication). Organic matter is introduced into the cave mainly by flood pulses, which allow the transport of leaf litter, root growth and even the capture of fish inside the cave. Almost entirely composed of aphotic zones with high isolation and humidity (Robson de Almeida Zampaulo personal communication). This new species occurs in other caves in the surroundings (02L, 25L 27L, 34L, 40L, 44L, 48L, 51L, 77L in the Limeira Massif and ES03, ES05, ES13, ES 17 in the Escrivânia massif,) with characteristics similar to those of the type locality. In addition to the troglomorphic pseudoscorpions, biological sampling of the cave fauna has recorded spiders, collembola.

Figures

FIGURE 3. A. Holotype ♂ of Pseudochthonius limettioides sp. nov. in 01L cave, Prudente de Morais, Minas Gerais (Image: Robson A. Zampaulo); B. Paratype ♂ of Pseudochthonius limettioides sp. nov, habitus and C. ventral view; D. Alotype ♀ of Pseudochthonius limettioides sp. nov, habitus and E. ventral view.

FIGURE 4. Pseudochthonius limettioides sp. nov., holotype (♂). A. anterior margin of the carapace; B. carapace; C. cheliceral movable finger of ♀; D. left chelicera; E. right chela, prolateral view with trichobothria pattern; F. right chelal dentition; black arrows show the terminal isolated tooth; G. right palpal (except chela); H. coxal spines on coxa I and II and the detail of the “grater” pattern on coxa II; I. genital opening.

Tables

TABLE 1. Measurements (in mm) of the holotype (male), allotype and paratypes of Pseudochthonius limettioides sp. nov.

	Holotype (male)	Female allotype (paratypes)
Body	1.34	1.42 (1.04–1.45)
Carapace	0.29/0.26 [0.18]	0.32/0.26[0.20] (0.20–0.33/0.16–0.20)
Pedipalp femur	0.57/0.1	0.63/0.1 (0.46–0.67/0.1)
Pedipalp patella	0.22/0.11	0.27/0.12 (0.21–0.28/0.10–0.12)
Pedipalp chela	0.84/0.13	0.92/0.15 (0.72–0.93/0.12–0.15)
Pedipalp hand length	0.29	0.34 (0.22–0.36)
Pedipalp movable finger length	0.54	0.55 (0.45–0.56)
Chelicera length/width	0.34/0.16	0.42 (0.31–0.20
movable finger length	0.18	0.20
Leg I femur	0.29/0.05	0.32/0.05 (0.25–0.30/0.05)
Leg I patella	0.17/0.05	0.21/0.05 (0.13–0.17/0.04–0.05)
Leg I tibia	0.16/0.04	0.18/0.04 (0.16–0.20/0.04)
Leg I tarsus	0.29/0.03	0.35/0.03 (0.27–0.34/0.03)
Leg IV femur+patella	0.45/0.19	0.47/0.17 (0.35–0.51/0.17–0.19)
Leg IV tibia	0.29/0.07	0.29/0.07 (0.22–0.31/0.06–0.07)
Leg IV basitarsus	0.14/0.05	0.18/0.05 (0.13–0.19/0.04–0.05)
Leg IV tarsus	0.31/0.03	0.37/0.03 (0.30–0.35/0.03)