Charinus caatingae, Vasconcelos, Ana Caroline Oliveira & Ferreira, Rodrigo Lopes, 2016

Vasconcelos, Ana Caroline Oliveira & Ferreira, Rodrigo Lopes, 2016, Description of two new species of Charinus Simon, 1892 from Brazilian caves with remarks on conservation (Arachnida: Amblypygi: Charinidae), Zootaxa 4072 (2), pp. 185-202 : 187-189

Charinus caatingae sp. n.

( Figs. 1–11 )

Type material. BRAZIL: Bahia: Várzea Nova: Fazenda Jurema cave (11º03 23.51"S, 41º05 34.47”W): Female holotype: 21.I.2012, leg. R. L. Ferreira ( ISLA 3918); Female paratypes: 02.I.2008, leg. R. L. Ferreira ( ISLA 3919; ISLA 3920; ISLA 3921; ISLA 4104); Female paratypes: 07.I.2014, leg. R. L. Ferreira ( ISLA 4996; ISLA 4997). Male unknown.

Diagnosis. Charinus caatingae differs from others species of the genus by having the following combination of characteristics: anterior margin of the carapace slightly elongated with 8 strong setae; lateral eyes underdeveloped, being reduced by only an eyespot; tritosternum with 1 apical pair and 2 median pair of strong setae; pedipalpal femur with 5 dorsal spines (4 can be found) and 5 ventral (4 can be found), pedipalpal patella with 5 dorsal spines (can be found one more basal of reduced size) and 3 ventral (can be found one more basal of reduced size), and pedipalpal tarsus with 3 dorsal spines on the cleaning organ; female gonopods sucker-like, with length similar to the width, opening rounded, edges with a small fold and a pronounced bottleneck below these.

Description. Carapace ( Figs. 1–3 ): Flattened. Ratio length/width slightly more than 3/4. Anterior margin slightly elongated, with corners flattened downwards; 8 strong setae on the anterior margin projected upwards, the central two located directly in front of the median eyes tubercle. Frontal process triangular in shape, with thickened apex, length similar to the width and not visible in dorsal view. Carina begins at the corners of the anterior margin and extends from the coxa of legs II to the corners of the posterior margin. Median eyes developed, with low tubercle, located in a small depression. Lateral eyes underdeveloped, without pigmentation (little pigmentation in juvenile) and with 1 small posterior seta. Frontal hump present at each side, starting just at the front of the lateral eyes and ending in a depression located at each side; fovea located posterior to the center, from which radiate two pairs of furrows in anterior and posterior orientation like an X; median depression located on each side between these two pair of furrows; a thin furrow follows medially from the median eye tubercle and reaches the posterior margin. Punctuations in lines and spots, more dense in the anterior region.

Sternum ( Fig. 5 ): Tri-segmented, with all segments sclerotized and convex. Tritosternum projected anteriorly, elongated and cone-shaped, with one apical and two medial pairs of strong setae, and some setulae in the base. Second segment (tetrasternum) slightly conical shaped, with one strong seta at each upper corner and some setulae encircling the base. Third segment (pentasternum) a little more flattened than the second, with one strong seta at each upper corner and few setulae encircling the base. The segments are separated from each other approximately by the diameter of the tetrasternum.

Abdomen ( Fig. 1 ): Oblong, with punctuations distinguishable.

Chelicera ( Fig. 4 ): Cheliceral furrow of the basal segment with 4 inner teeth. The distal tooth is bifid, the distal cusp being larger than the proximal. Teeth length: IV>Ia>Ib=II>III. Claw with 8 denticles (can be found up to 10). Strong setae located distally on the dorsal side of the chelicera.

Pedipalp ( Figs. 6–8 ): Trochanter: Ventral spiniform apophysis pointed forwards with a series of strong setiferous tubercles. 2 spines aligned on the prolateral face, the first being near to the medial region, and the second above the projection of the apophysis and close to the femur. First spine is slightly thinner than the second one. Second spine and the spine AI of the ventral femur are subequal in some specimens. One or two strong setae of basal location to the first spine and three aligned between the two spines. Dorsal series of strong setae. Femur: Strong dorsal setae. 5 dorsal spines (4 can be found) of sizes: F1>F2>F3>F4>F5. 5 ventral spines (4 can be found) of sizes: FI>FII>FIII>AI>FIV. Patella: Strong dorsal setae between the spines. 5 dorsal spines (can be found one more basal of reduced size) of sizes: 1>2>3>A1>4>5. Strong ventral setae. 3 ventral spines (can be found one more basal of reduced size) of sizes: I>II>III. The spines III and IV (when present) are generally pointed forward. Tibia: Strong dorsal setae. 2 dorsal spines, spine 2 being approximately twice larger than the spine 1. One strong ventral setae in the basal portion of the ventral spine. 1 ventral spine located in the distal half of size slightly smaller than dorsal spine 1. Tarsus: Several strong dorsal setae and long ventral setae. 3 dorsal spines on the cleaning organ in ascending order of size, the third being three times larger than the first spine ( Fig. 8 ). Cleaning organ occupies about half the length of the article. Claw: Long with sharp curved tip.

Legs: All densely setose. Femur lengths: I>III>II>IV. Leg I: Tibia with 23 articles and tarsus with 41 articles. Leg IV ( Fig. 9 ): Basitibia with 4 pseudo-articles. One trichobothrium located proximally on the last article. Distitibia with 3 trichobothria positioned proximally and 15 trichobothria positioned distally; frontal and caudal series with 6 trichobothria each. Basitibia-distitibia length: DT>BT1>BT4>BT2=BT3. Ratio tarsus/metatarsus is approximately 3/4. Tarsus composed of 4 segments.

Measurements (total specimens=7): Total length: 8.29 mm (5.29–12.60). Cephalothorax: Length: 3.10 mm (2.32–4.54); Width: 4.03 mm (2.96–5.70). Pedipalp: Femur: 2.24 mm (1.38–4.21); Patella: 2.43 mm (1.48–4.75); Tibia: 1.13 mm (0.78–1.89); Tarsus: 0.86 mm (0.62 – 1.38); Claw: 0.70 mm (0.52–1.06). Measurements (fullygrown specimens=4): Total length: 9.91 mm (8.84–12.60). Cephalothorax: Length: 3.60 mm (3.08–4.54); Width: 4.69 mm (3.88–5.70). Pedipalp: Femur: 2.80 mm (2.02–4.21); Patella: 3.05 mm (2.11–4.75); Tibia: 1.35 mm (1.08–1.89); Tarsus: 1.01 mm (0.84 – 1.38); Claw: 0.81 mm (0.64–1.06).

Color: Body light brown with reddish chelicerae ( Fig. 11 E). In alcohol ( Fig. 1 ): Body yellowish brown in general. Some specimens exhibit slightly reddish coloration on the carapace, pedipalps, chelicerae and legs.

Genitalia: Female ( Fig. 10 ): Rounded genital operculum margin with few scattered setae. Gonopods suckerlike, barrel shaped and with length similar to the width. Gonopods opening rounded; edges with a small fold and a pronounced bottleneck below these. Gonopods separated from each other by a distance smaller than its diameter and positioned from the margin of the operculum by a distance larger than its length.

Etymology. The specific epithet “ caatingae ” is treated as a noun in apposition and refers to the biome (Caatinga) where the species inhabits.

Natural history. The Fazenda Jurema cave belongs to the Una limestone group ( Fig. 27 ), and is located in the Caatinga biome, which is the only semi-arid biome occurring in Brazil ( Fig. 11 A) ( De Oliveira et al. 2012). It comprises a relatively small cave (around 100 meters long), with a single small entrance. The cave conduit descends in a considerable slope reaching the final chamber, in which the phreatic level is observed. Specimens were mainly found in this final portion of the cave. Many other caves were sampled in the area, and specimens of C. caatingae were only found in the Fazenda Jurema cave, which suggests that the species is endemic to this single locality. Potential preys include crickets ( Endecous sp.) and moths ( Tineidae ).

The external vegetation was partially removed for the establishment of corn and manioc crops. In the first visit to the cave (in 2008), apparently the entrance had not been modified by human activities ( Fig. 11 B). However, in 2014, the last visit to the area, we asserted that an electric pump was installed inside the cave to pump water for crop irrigation ( Fig. 11 D). Among the anthropogenic impacts, we can emphasize electric light installation and modifications in the surrounding area near the cave entrance ( Fig. 11 C). Due to all these harsh influences inside and outside the cave, it is likely that this species is severely threatened. Accordingly, urgent actions are required in this cave in order to protect this endangered species and its natural habitat.

Figures

FIGURE 11. Charinus caatingae sp. n.: A. External environment of the Fazenda Jurema cave. B. Entrance of the cave in 2008. C. Entrance modified by human activities in 2014. D. Electric pump inside the cave. E. Female inside the Fazenda Jurema cave.

FIGURE 27. Map of Bahia state with the limestone groups represented. A. Locality of Charinus caatingae. B. Locality of Charinus iuiu.

FIGURES 1 – 8. Charinus caatingae sp. n.: Holotype: 1. Habitus. Scale bar = 2 mm. 2. Carapace. Scale bar = 1 mm. 3. Frontal view of the carapace and frontal process. Scale bar = 500 µm. Paratype: 4. Right chelicerae. Scale bar = 500 µm. Holotype: 5. Sternum. Scale bar = 500 µm. 6. Right pedipalp in ventral view. 7. Right pedipalp in dorsal view with spines on the tarsus detached. Scale bar = 1 mm. 8. Spines on the tarsus of the right pedipalp in detail.

FIGURES 9 – 10. Charinus caatingae sp. n.: Holotype: 9. Distitibia and last pseudo-article of the basitibia of the left leg IV. Scale bar = 1 mm. 10. Female gonopod. Scale bar = 250 µm.