Charinus iuiu, 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 : 190-195

Charinus iuiu sp. n.

( Figs. 12–26 )

Type material. BRAZIL: Bahia: Iuiu : Lapa do Baixão (14º23 8.13"S, 43º37 35.06”W): Female holotype: 07.VIII.2013, leg. R. L. Ferreira ( ISLA 4097); Female paratypes: 07.VIII.2013, leg. R. L. Ferreira ( ISLA 4098; ISLA 4099; ISLA 4101); Male paratype: 07.VIII.2013, leg. R. L. Ferreira ( ISLA 4100). BRAZIL: Bahia: Iuiu : Toca Fria (14º32´53"S, 43º32´10"W): Female paratype: 07.VIII.2013, leg. R. L. Ferreira ( ISLA 4103); Male paratype: 07.VIII.2013, leg. R. L. Ferreira ( ISLA 4102).

Diagnosis. Charinus iuiu differs from others species of the genus by having the following combination of characteristics: Anterior margin of the carapace with 6 strong and elongated setae; frontal process triangular in shape, longer than wide and with a thickened apex; chelicera claw with 10 denticles; pedipalp densely setose with femur with 4 dorsal spines (3 can be found) and 5 ventral (4 can be found), and patella with 6 dorsal spines (5 are found in smaller specimens) and 3 ventral; female gonopods sucker-like, with length larger than the width, opening rounded and a posterior slit to the upper region of each structure, edges with a fold and a small bottleneck below these; male gonopods with several long lobes (LoL2 and LoL1) emerging from the Fi.

Description. Carapace ( Figs. 12–14 ): Flattened. Ratio length/width slightly less than 3/4. Portions above the coxae of leg I slightly curved upwards. Anterior margin rounded, with corners flattened down; 6 strong and elongated 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, longer than wide and 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 slightly divided between the two eyes, and located in a small depression. Lateral eyes developed, with internal pigmentation and one seta posterior to each triad. 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. 16 ): Tri-segmented, with all segments sclerotized and convex. Tritosternum projected anteriorly, elongated and cone-shaped, with one apical pair, one medial and one basal pair of strong setae, and several setulae in the base. Second segment (tetrasternum) rounded, with one strong setae at each upper corner and several setulae encircling the base. Third segment (pentasternum) slightly smaller than the second, with one strong seta at each upper corner and several setulae encircling the base. The segments are separated from each other approximately by the diameter of the tetrasternum.

Abdomen ( Fig. 12 ): Oblong, with punctuations distinguishable.

Chelicera ( Fig. 15 ): Cheliceral furrow with 4 inner teeth in the basal segment. The distal tooth is bifid, with the distal cusp slightly larger than the proximal. Teeth length: IV>Ia>Ib=II>III. Claw with 10 denticles. Strong setae located distally on the dorsal and on the surface of the inner side of the chelicera.

Pedipalp ( Figs. 17–19 ): Trochanter: Ventral spiniform apophysis pointed forwards with a series of strong setiferous tubercles. 2 subequal spines aligned on the prolateral face, the first being close to the medial region and the second above the projection of the apophysis and close to the femur. Three strong setae, on average, of basal location to the first spine and three or four setae aligned between the two spines. Femur: Many strong dorsal setae along the segment. 4 dorsal spines (3 can be found) of sizes: F1>F2>F3>F4. 5 ventral spines (4 can be found) of sizes: FI>FII>FIII>AI>FIV. Patella: Densely setose. 6 dorsal spines (5 are found in smaller specimens) of sizes: 1>2>3>A1>4>5. 3 ventral spines of sizes: I>II>III. Tibia: Densely setose with long ventral setae. 2 dorsal spines, spine 2 being almost three times larger than spine 1. 1 ventral spine located in the distal half slightly larger to almost twice the size of dorsal spine 1. Tarsus: Densely setose with long ventral setae. 2 spines above the cleaning organ, the second being two to three times larger than the first spine ( Fig. 19 ). Cleaning organ occupies about half the article length. 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. 20 ): 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>BT3>BT2. Ratio tarsus/metatarsus is approximately 3/4. Tarsus composed with 4 segments.

Measurements (total specimens=7): Total length: 9.80 mm (6.64–13.92). Cephalothorax: Length: 3.22 mm (2.43–3.97); Width: 4.46 mm (3.19–5.57). Pedipalp: Femur: 2.50 mm (1.20–3.72); Patella: 2.79 mm (1.51–4.00); Tibia: 1.34 mm (0.8–1.75); Tarsus: 1.01 mm (0.68–1.32); Apotele (claw): 0.68 mm (0.44–0.94). Measurements (fully-grown specimens=4): Total length: 11.71 mm (10.40–13.92). Cephalothorax: Length: 3.69 mm (3.46–3.97); Width: 5.12 mm (4.59–5.57). Pedipalp: Femur: 3.15 mm (2.48–3.72); Patella: 3.48 mm (2.72–4.00); Tibia: 1.62 mm (1.32–1.75); Tarsus: 1.18 mm (1.01–1.32); Apotele (claw): 0.79 mm (0.62–0.94).

Color: Body grayish brown, abdomen with lighter coloring and reddish chelicerae ( Figs. 26 C–26D). In alcohol ( Fig. 12 ): Body reddish brown with the abdomen yellowish brown.

Genitalia: Female ( Fig. 21 ): Rounded genital operculum margin with many strong setae. Gonopods suckerlike, barrel shaped and with length larger than the width. Gonopods opening rounded and with a posterior slit to the upper region of each structure. Gonopods edges with a fold and a small bottleneck below these. Gonopods separated from one another by a distance slightly smaller than the diameter of each one and from the margin of the operculum by a distance slightly larger than its length. Male ( Figs. 22–25 ): Margin of GO rounded with a few scattered setae. Genitalia wider than long. Fi exceeds the genital operculum margin, with sclerotized bands surrounding each side. Several long lobes (LoL2 and LoL1) emerge from each side of the gonopod tube. A pair of lobes (LoD) located dorsally in the interior of the gonopod ( Fig. 24 ). A pair of small lobes (LaM) located medially and ventrally to the Fi ( Fig. 25 ).

Etymology. The specific epithet “ iuiu ” is treated as a noun in apposition and refers to the municipality where the species inhabits.

Natural history. The specimens were found in “Lapa do Baixão” and in “Toca Fria” caves, both located in Iuiu municipality (Bahia state, Brazil), belonging to the Bambuí limestone group ( Fig. 27 ). Some other caves in the area were also inventoried, but specimens were only found in these two caves, which are located around 18 km apart from each other. This area is located in the domains of the Caatinga biome ( Fig. 26 A). The surroundings of the entrance in both caves are severely impacted, mainly by human activities such as agriculture, extensive cattle and goat breeding. Such activities have resulted in a rather fragmented landscape, where remaining vegetation is mainly associated with the tops of outcrops (inappropriate areas for human use).

The main population of Charinus iuiu was found in Lapa do Baixão cave, which comprises a labyrinthic cave in which some inner chambers become flooded during rainy periods. The only known entrance (with small dimensions - 1m 2) is located at the bottom of a subsidence sinkhole, which makes the cave atmosphere quite isolated from the external environment. Many roots, which constitute an important nourishment source for the hypogean fauna, were observed inside the cave ( Fig. 26 B). Specimens of C. iuiu were mainly observed in deeper zones within the cave, and potential prey includes especially crickets ( Endecous sp.). Fortunately, this cave has not been visited by anyone except the research team, so it is quite preserved.

Two specimens were found in Toca Fria cave. This cave comprises the biggest known cave in the Iuiu municipality. It has around 2 km of labyrinthic galleries with many connections to the external environment. The huge number of entrances (with distribution spread along the cave) promotes a higher influence of the external climate (which is mainly dry) on the cave atmosphere. Accordingly, most areas within this cave are dry. The specimens were found under rocks on the cave floor. The Toca Fria cave is regularly visited by locals, exhibiting some impacts (such as trampling and graffiti) arising from these visits.

Figures

FIGURE 26. Charinus iuiu sp. n.: A. External environment of the Lapa do Baixão cave. B. Interior of the Lapa do Baixão cave where specimens were collected. C. Individual inside the cave. D. Female with egg sac.

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

FIGURES 12 – 19. Charinus iuiu sp. n.: Holotype: 12. Habitus. Scale bar = 2 mm. 13. Carapace. Scale bar = 1 mm. 14. Frontal view of the carapace and frontal process. Scale bar = 1 mm. Female paratype: 15. Right chelicerae. Scale bar = 500 µm. Holotype: 16. Sternum. Scale bar = 500 µm. 17. Right pedipalp in ventral view. 18. Right pedipalp in dorsal view with spines on the tarsus detached. Scale bar = 2 mm. 19. Spines on the tarsus of the right pedipalp in detail.

FIGURES 20 – 23. Charinus iuiu sp. n.: Holotype: 20. Distitibia and last pseudo-article of the basitibia of the right leg IV. Scale bar = 1 mm. 21. Female gonopod. Scale bar = 250 µm. Paratype: 22. Dorsal view of the male gonopod. Scale bar = 500 µm. 23. Ventral view of the male gonopod. Scale bar = 250 µm.

FIGURES 24 – 25. Charinus iuiu sp. n.: Male paratype: 24. Dorsal view of the gonopod with LoD detached in dashed lines. 25. Ventral view of the gonopod with LaM detached in dashed lines.