Pseudochthonius ramalho Assis, Schimonsky & Bichuette, 2021

Assis 1, Leonardo de, Schimonsky 1, Diego Monteiro von & Bichuette 1, Maria Elina, 2021, The first troglobitic Pseudochthonius Balzan, 1892 (Pseudoscorpiones, Chthoniidae) from the karst area of Serra do Ramalho, Brazil: a threatened species, Subterranean Biology 40, pp. 109-128 : 109

Pseudochthonius ramalho Assis, Schimonsky & Bichuette sp. nov.

Figs 3 , 4 , 5 , 6 , 7 , 8

Type material.

Holotype: 1 ♂ (LES9601) Brazil Caatinga province, Serra do Ramalho karst area, Serra do Ramalho, Bahia, Gruna do Vandercir cave; 13°38'11.40"S, 43°50'5.10"W; 31 May 2012; Bichuette ME, Gallão JE, Hattori N leg. Paratype: 1 ♀ (LES9602), same data as holotype.

Etymology.

The species is named after the region of Serra do Ramalho due to its importance regarding the speleological heritage and the unique fauna and flora diversity. The name is to be treated as a noun in apposition.

Diagnosis.

Pseudochthonius ramalho sp. nov. can be identified by the following combination of characters: eyes absent (♂) or with eyes-spots (♀); the middle and distal fixed chelal finger teeth positioned two by two with 29-30 acuminate teeth and 3-4 slightly basally rounded ones, the presence of two rounded micro-denticles, along with pedipalpal fixed finger teeth in males; trichobothria ist closer to esb than to the est (ratio ist - est / ist - esb = 4.71); serrula exterior with 13 (♂) or 14 (♀) lamellae, rallum with seven blades, and coxae I and II with 3 to 5 coxal spines.

Description

(adult ♂ and ♀). Body: Coloration of specimens in 70% ethanol yellowish brown and translucent pedipalps, tergites III-V with a dark median mark, and a darker abdominal region. Live specimens present a light pinkish color on their carapace and appendages, and a light brown abdomen. Female is slightly smaller than male.

Chelicera (Figs 6A , 7B, C ): five setae on left hand, with one seta on the basal position of the fixed finger and one nearly the basal seta on the movable finger; six setae on the right hand; without the lateral microsetae; fixed finger with 10-11 (♂ and ♀) teeth proximally reduced in size; movable finger with 9 (♂) or 8(♀) teeth proximally reduced in size, three distal teeth distinctly larger than others and with subapical isolated tooth (di). Spinneret moderately prominent and apically rounded in female, vestigial in male. Seta gl 0.15 mm from base of movable finger. Serrula exterior with 13 (♂),14 (♀) lamellae. Rallum with seven blades pectinated. Dorsal face of cheliceral palm with four lyrifissures, three lyrifissures situated near seta dt and one situated posteriorly.

Pedipalp (Figs 6B-D , 8A-F ): 1.4 (♂),1.2 (♀) × longer than carapace and 2.2 (♂), 2.6 (♀) × longer than patella; movable finger 1.6 (♂), 1.9 (♀) × longer than hand; fixed finger 1.65 (♂),1.72 (♀) × longer than hand. Fixed chelal finger long and strongly sigmoid in its distal half. Male fixed finger with 33 acute teeth, distinctly separated from each other, but paired and in each pair, one tooth is slightly directed to inside and the other to the outside, and micro-denticles in two interdental spaces, on teeth 15 and 29, respectively. Female fixed finger with 31 teeth arranged as in as in male. Movable finger with 30-33(♂ and ♀) flattened and separated teeth. Trichobothria: ib and isb situated close to each other sub-medially in the dorsal region of the chelal hand; eb closer to esb than to ist, forming a straight oblique row at the base of the fixed chelal finger; ist closer to esb than to the est (ratio ist - est/ist - esb = 4.71); et slightly near the tip of the fixed finger, near to the chelal teeth; dx, located near to the end of the fixed finger; sb closer to b than to st in the movable chelal finger (ratio sb - st/sb - b = 3.37); t closer to st and situated at the same level as est.

Carapace (Fig. 7A ): Carapace 1.09 × longer than broad, posteriorly constricted, chaetotaxy 4:4:4:2:2 (16), one preocular microseta on each side; eyes absent on male and a tiny eyespot on female; anterior margin distinctly serrate with median denticles larger than lateral ones; epistome prominent and dentate (Fig. 7A-C ); 3 lyrifissures anteriorly, 1 medially and 2 posteriorly.

Abdomen: Chaetotaxy of tergites I-XI: ♂, 4: 4: 4: 4: 6: 6: 6: 6: 6: 5: 3; ♀, 4: 4: 4: 4: 5: 6: 6: 6: 6: 5: 3. Chaetotaxy of sternites III-XI: (♂/♀) 12: 13: 8: 8: 8: 8: 6: 5: 2, anal cone 0/2 setae.

Genital area: Anterior genital operculum with 8 (♂), 9 (♀) marginal and discal setae, arranged triangularly in male, with 7-8 unmodified marginal setae on each side; posterior operculum with 6 setae in female.

Coxae (Fig. 7D, E ): Manducatory process distally acute, with 2 setae; pedipalpal coxa with 3 setae, coxa I and II with 4-5 setae on anterior margin and 3-5 highly dented coxal spines in decreasing size distally, coxa III with 7 setae and coxa IV with 8 setae; intercoxal tubercle absent.

Legs (Fig. 7F, G ): Typical of the genus ( Chamberlin 1929).

Measurements and ratios: see Table 1 .

Figures

Figure 3. Holotype of Pseudochthonius ramalho sp. nov. in natural habitat, at Gruna do Vandercir cave, Serra do Ramalho, Bahia. (Image: Adriano Gambarini).

Figure 4. Pseudochthonius ramalho sp. nov. holotype male, habitus A dorsal view B ventral view.

Figure 5. Pseudochthonius ramalho sp. nov. scanning electron images. Paratype female, habitus A dorsal view B ventral view C zoom in on the anterior margin of the carapace with eye spots denoted with red circle. (Images: Luciana B. R. Fernandes).

Figure 6. Pseudochthonius ramalho sp. nov. female paratype scanning electron images A detail on the right chelicera of serrula exterior and rallum B detail on the right pedipalp trichobothrium isb and ib, lateral C left pedipalp D detail on the left pedipalp teeth. (Images: L. B. R. Fernandes).

Figure 7. Pseudochthonius ramalho sp. nov., male A carapace dorsal view, and detail of the anterior margin (with the epistome) B right chelicera (dorsal view) C detail of the rallum D coxa I and II E details of coxal spines F leg I (lateral view) G leg IV (lateral view).

Figure 8. A holotype left pedipalp showing the trichobothria distribution B details of chelal teeth C distal part of fixed chelal finger (lateral view) D detail with emphasis on the micro-denticles in two interdental spaces, on teeth 15 and 29, respectively E pedipalp femur F distal part of fixed chelal finger (ventral view).