taxonID	type	description	language	source
03E987CAFFAF8F20FF48E231FF7245EB.taxon	materials_examined	Material Examined. Holotype female (ISLA 126406), preserved in ethanol: Brazil, Iuiú, Bahia, Olho D’água do Coitezeiro (14 ° 27 ' 58.76 " S 43 ° 39 ' 26.24 " W), October 26, 2021, collected by R. L. Ferreira. Paratype male (ISLA 126407), Paratype female (ISLA 126409) same data as the holotype.	en	Guimarães, Lucas, Prado, Guilherme C., Ferreira, Rodrigo L. (2025): Two new species of Tyrannochthonius Chamberlin, 1929 (Pseudoscorpiones: Chthoniidae) from caves in Brazilian semiarid region. Zootaxa 5706 (3): 367-382, DOI: 10.11646/zootaxa.5706.3.3, URL: https://doi.org/10.11646/zootaxa.5706.3.3
03E987CAFFAF8F20FF48E231FF7245EB.taxon	etymology	Etymology. The specific epithet iuiu is a noun in apposition and refers to Serra de Iuiú (Iuiú Hill), southwestern Bahia State, Brazil, where the species was discovered.	en	Guimarães, Lucas, Prado, Guilherme C., Ferreira, Rodrigo L. (2025): Two new species of Tyrannochthonius Chamberlin, 1929 (Pseudoscorpiones: Chthoniidae) from caves in Brazilian semiarid region. Zootaxa 5706 (3): 367-382, DOI: 10.11646/zootaxa.5706.3.3, URL: https://doi.org/10.11646/zootaxa.5706.3.3
03E987CAFFAF8F20FF48E231FF7245EB.taxon	diagnosis	Diagnosis. Tyrannochthonius iuiu sp. nov. most closely resembles T. migrans based on the following combination of characters: presence of two pairs of eyes, carapace chaetotaxy 4 + 2: 4: 4: 2: 2, chelicerae with five setae on the hand, number of teeth on the movable cheliceral finger (10 – 12 in T. iuiu sp. nov. and 10 – 15 in T. migrans), and coxal chaetotaxy 3: 4: 5: 5 (including coxal spines). It differs from T. migrans in number of chelal teeth: fixed finger with 23 teeth and 11 intercalary microdenticles (in T. migrans 16 – 19 teeth and 7 – 9 microdenticles), movable finger with 20 teeth (in T. migrans 10 – 12), movable chelal finger 1.6 – 1.7 times longer than hand (in T. migrans 2.1 – 2.2); presence of two lyrifissures on sternite II, one on each side of genital opening; leg I tarsus 10.3 longer than wide (in T. migrans 7.0 – 7.9); leg IV tarsus 11.0 longer than wide (in T. migrans 7.3 – 8.7).	en	Guimarães, Lucas, Prado, Guilherme C., Ferreira, Rodrigo L. (2025): Two new species of Tyrannochthonius Chamberlin, 1929 (Pseudoscorpiones: Chthoniidae) from caves in Brazilian semiarid region. Zootaxa 5706 (3): 367-382, DOI: 10.11646/zootaxa.5706.3.3, URL: https://doi.org/10.11646/zootaxa.5706.3.3
03E987CAFFAF8F20FF48E231FF7245EB.taxon	description	Description. Body beige, slightly translucent, with darker chelicerae and carapace (Figs 1 A, C), vestitural setae simple, thin and sharp, anteriorly projected on the prosoma and posteriorly projected on the opisthosoma. Carapace. Slightly constricted posteriorly, with a small difference between ocular width and posterior width of 0.09 mm. Surface smooth, without any furrows. Presence of two pairs of eyes, the anterodorsal ones without defined lens (Fig. 2 C). Anterior margin smooth, epistome bifid and small, with 2 setae flanking the base (Fig. 2 A). Carapace chaetotaxy: 4 + 2: 4: 4: 2: 2 (18), simple setae, median lateral ones shorter. Tergites. Undivided, smooth surface. Chaetotaxy uniseriate: I – XI 4: 4: 4 (6): 6: 6 (5): 6 (5): 6: 6: 6: 6: 4. Coxae. Palpal: Manducatory process with two acuminate distal setae, and 3 coxal setae arranged in a triangle. Pedal: Apex anterior of coxae I with an acute projection (Fig. 3 D), coxae II with six coxal spines with branched apex (4 – 6 branches each, Fig. 2 D), arranged in an oblique row (Figs 3 B, D). Intercoxal tubercle absent. Chaetotaxy of pedal coxae: 3: 4: 5: 5. (Fig. 3 D). Male genital operculum. Genital opening slit-like; sternite II with 6 – 7 setae; sternite III with 8 – 7 marginal setae on each side; one pair of lyrifissures on each side of sternite III (Fig. 3 C). Female genital operculum. Sternite II with 5 – 6 setae on posterior margin, sternite III with 9 setae scattered on median area. (Fig. 2 E). Sternites. Male chaetotaxy III ‒ XI: 8: 10: 10: 8: 8: 8: 8: 4, anal operculum with 2 ventral setae. Female chaetotaxy IV – XI: 8: 9: 7: 6: 7: 7: 7: 2 + 2 anal setae. Chelicerae. 0.21 times longer than wide. Hand with 5 setae (Fig. 2 B), 3 lyrifissures at the base of the fixed finger (dorsally visible) and small spines projecting anteriorly (Figs 4 C, D). Movable cheliceral finger with 1 medial seta (Fig. 4 D), and 12 acute teeth (4 proximal ones shorter), galea absent; fixed cheliceral finger with 6 teeth (including a large distal one). External and internal serrulae with 17 and 13 blades, respectively. Rallum with 7 unilaterally pinnate blades (Figs 4 C, D). Pedipalp. Trochanter 1.74, femur 4.67, patella 2.39, chela 4.75, hand 1.93 times as long as wide; femur 2 times as long as patella; movable chelal finger 1.57 times as long as hand and 0.41 times as long as chela. Movable chelal finger with apodeme slightly sclerotized, with 24 (23) well-spaced acute teeth (except the six most basal ones, which are vestigial and rounded), and 5 (6) intercalary microdenticles in the distal portion (Figs 4 A, B). Fixed chelal finger with 23 acute teeth, 11 intercalary microdenticles along almost entire length, and 6 vestigial teeth in the basal region (Figs 4 A, B). Trichobothria: ib and isb adjacent, located submedially on the dorsum of the hand. In the fixed finger, esb is slightly distal to eb and slightly more distal to ist. In the posteromedial portion, it is slightly distal to est. In the distal portion, et is proximal to dx. In the movable finger, sb is halfway between b and st; t is distal to b (Fig. 4 A), b much closer to t than sb (ratio distance sb – b / b – t = 4.2). Leg I. Femur 2.00 times as long as patella, tarsus 2.06 times as long as tibia. Arolium undivided, slightly shorter than simple claws. One lyrifissure at the apex of the femur (Fig. 5 C). Leg IV. Femur and patella 2.86 times as long as wide, tibia 4.85 times as long as wide, basitarsus 3.00 times as long as wide, telotarsus 11.0 times as long as wide and 2.20 times as long as basitarsus. Arolium undivided, slightly shorter than simple claws. One lyrifissure at the anterior face of the femur (Fig. 5 A). Measurements (mm): (length / width or depth in mm and ratios in parentheses calculated with three significant digits). Female holotype: Body length 1.39 (male paratype 1.00 mm [measured during SEM analysis]). Carapace 0.41 / 0.44 (0.93). Palps: trochanter 0.19 / 0.11 (1.72), femur 0.48 / 0.10 (4.8), patella 0.24 / 0.10 (2.4), chela 0.72 / 0.15 (4.8), movable finger length 0.46. Leg I: trochanter 0.12 / 0.09 (1.33), femur 0.28 / 0.06 (4.66), patella 0.14 / 0.05 (2.8), tibia 0.15 / 0.04 (3.75), tarsus 0.31 / 0.03 (10.3). Leg IV: trochanter 0.12 / 0.10 (1.2), femoropatella 0.49 / 0.19 (2.57), tibia 0.34 / 0.06 (5.66), basitarsus 0.15 / 0.05 (3.0), telotarsus 0.33 / 0.03 (11.0). Ecological Remarks. Specimens of Tyrannochthonius iuiu sp. nov. are exclusively recorded in Olho D’Água do Coitezeiro Cave, located in the municipality of Malhada, Bahia State, Brazil. This cave features a single entrance (Fig. 6 B), formed by the resurgence of a subterranean drainage system that remains active throughout the year (Fig. 6 D), although discharge volume varies considerably between the dry and rainy seasons. The main conduit, shaped by the drainage flow, is relatively narrow but connects to upper-level passages and galleries (Fig. 6 C). These elevated areas remain humid but are not directly influenced by flowing water. Tyrannochthonius iuiu sp. nov. was observed within one of these upper galleries, sheltered beneath rocks on the cave floor. Potential prey, such as springtails (Collembola) and mites, were also present in the same microhabitats. Olho D’Água do Coitezeiro Cave is situated atop the Serra do Iuiú, where the surrounding vegetation remains relatively well preserved (Fig. 6 A). The rugged terrain created by limestone outcrops limits access and has restricted agricultural and livestock activities in the area. Furthermore, the cave interior shows minimal signs of human disturbance, indicating a high level of habitat integrity.	en	Guimarães, Lucas, Prado, Guilherme C., Ferreira, Rodrigo L. (2025): Two new species of Tyrannochthonius Chamberlin, 1929 (Pseudoscorpiones: Chthoniidae) from caves in Brazilian semiarid region. Zootaxa 5706 (3): 367-382, DOI: 10.11646/zootaxa.5706.3.3, URL: https://doi.org/10.11646/zootaxa.5706.3.3
03E987CAFFAA8F2BFF48E254FDC846F7.taxon	materials_examined	Material Examined. Holotype male (ISLA 126405), preserved in ethanol: Brazil, Iuiú, Bahia, Morro do Aurélio cave (14 ° 30 ' 49.34 " S, 43 ° 32 ' 35.56 " W), October 20, 2021, collected by Ferreira, R. L.	en	Guimarães, Lucas, Prado, Guilherme C., Ferreira, Rodrigo L. (2025): Two new species of Tyrannochthonius Chamberlin, 1929 (Pseudoscorpiones: Chthoniidae) from caves in Brazilian semiarid region. Zootaxa 5706 (3): 367-382, DOI: 10.11646/zootaxa.5706.3.3, URL: https://doi.org/10.11646/zootaxa.5706.3.3
03E987CAFFAA8F2BFF48E254FDC846F7.taxon	etymology	Etymology. The specific epithet aratu refers to the Aratu ceramic tradition, an archaeological complex associated with pre-colonial indigenous peoples from the interior regions of northeastern Brazil. The name honors the cultural history of the region where the species was discovered. This should be treated as a noun in apposition.	en	Guimarães, Lucas, Prado, Guilherme C., Ferreira, Rodrigo L. (2025): Two new species of Tyrannochthonius Chamberlin, 1929 (Pseudoscorpiones: Chthoniidae) from caves in Brazilian semiarid region. Zootaxa 5706 (3): 367-382, DOI: 10.11646/zootaxa.5706.3.3, URL: https://doi.org/10.11646/zootaxa.5706.3.3
03E987CAFFAA8F2BFF48E254FDC846F7.taxon	diagnosis	Diagnosis. Tyrannochthonius aratu sp. nov. most closely resembles T. rotundimanus in the following combination of characters: presence of two pairs of eyes, a small triangular smooth epistome, carapace chaetotaxy of 4 + 2: 4: 4: 2: 2, cheliceral dentition with 7 teeth on the movable finger and 10 teeth on the fixed finger, and coxal chaetotaxy of 3: 4: 5: 5. It differs from T. rotundimanus by more elongate pedipalp: femur 4.9 longer than wide (in T. rotundimanus 3.7 – 4.0), chela 5.0 longer than wide (in T. rotundimanus 4.5 – 4.7), femur / patella ratio 2.34 (in T. rotundimanus 1.94 – 2.01), fixed chelal finger with 30 teeth (in T. rotundimanus 18 – 22), fixed chelal finger with 9 intercalary microdenticles (in T. rotundimanus, 5); leg IV: tibia 4.8 longer than wide (in T. rotundimanus 2.9 – 3.1), telotarsus 11.0 longer than wide (in T. rotundimanus 6.0 – 7.6), basitarsus 3.0 longer than wide (in T. rotundimanus 2.2 – 1.8).	en	Guimarães, Lucas, Prado, Guilherme C., Ferreira, Rodrigo L. (2025): Two new species of Tyrannochthonius Chamberlin, 1929 (Pseudoscorpiones: Chthoniidae) from caves in Brazilian semiarid region. Zootaxa 5706 (3): 367-382, DOI: 10.11646/zootaxa.5706.3.3, URL: https://doi.org/10.11646/zootaxa.5706.3.3
03E987CAFFAA8F2BFF48E254FDC846F7.taxon	description	Description. Preserved specimen: Body slightly translucent light yellow; chelicerae and carapace slightly darker (Figs 1 B, D). Live specimen: Carapace brown (charred orange); abdomen dark burnt orange; chelicerae reddishorange; pedipalps slightly translucent, with a color resembling aged copper (Fig. 8 D). Vestitural setae simple, thin and sharp, anteriorly projected on prosoma and posteriorly projected on opisthosoma. Carapace. Slightly constricted posteriorly, with a small difference between ocular width and posterior width of 0.07 mm. Surface smooth, without any furrows. Presence of two pairs of eyes, the anterodorsal ones without defined lens. Anterior margin smooth, epistome triangular, small and smooth, with 2 setae flanking the base. Carapace chaetotaxy: 4 + 2: 4: 4: 2: 2 (18), simple setae, the median lateral ones shorter (Fig. 7 B). Tergites. Undivided, smooth surface. Chaetotaxy uniseriate: I – XI 4: 4: 6: 4: 6: 6: 6: 6: 7 (8): 4: 4. Coxae. Palpal: Manducatory process with two acuminate distal setae, and 3 coxal setae arranged in a triangle. Pedal: Apex anterior of coxae I with an acute projection, coxae II with 6 coxal spines with branched apex (4 – 6 branches each), arranged in an oblique row (Figs 7 A, F). Intercoxal tubercle absent. Coxal chaetotaxy: 3: 4: 5: 5 (Fig. 7 A). Male genital operculum. Genital opening slit-like; sternite II with 8 setae; sternite III with 7 marginal setae on each side (22 setae distributed throughout the sternite) (Fig. 7 G). Sternites. Chaetotaxy IV ‒ XI: 6: 6: 6: 8: 6: 6: 6: 8, anal operculum with 2 ventral setae. Chelicerae. 0.15 times longer than wide. Hand with 5 setae, movable finger with 1 medial seta. Movable cheliceral finger with 10 teeth (1 – 2 acute, 3 – 5 worn and 8 – 10 vestigial teeth), galea absent; fixed cheliceral finger with 7 teeth (most distal one larger and the second most distal bicuspid, followed by 3 smaller and acute teeth), basal ones with rounded apex (Fig. 7 H). External and internal serrula with 19 and 12 – 15 blades, respectively. Rallum with 6 unilaterally pinnate blades. Pedipalp. Trochanter 1.71, femur 4.91, patella 1.7, chela 5.18, hand 1.90 times as long as wide; femur 2.34 times as long as patella; movable chelal finger 1.64 times as long as hand and 0.62 times as long as chela. Movable chelal finger with apodeme slightly sclerotized, with 31 well-spaced and acute teeth, except for the four most basal, which are vestigial, rounded, and contiguous; 3 intercalary microdenticles in the distal portion. Fixed chelal finger with 30 well-spaced and strongly acute teeth; 9 intercalary microdenticles in the distal portion. Trichobothria: ib and isb adjacent, located submedially on the dorsum of the hand. Trichobothrium esb is slightly distal to eb and slightly more distal to ist. In the posteromedial portion, it is slightly distal to est. In the distal portion, et is proximal to dx. On movable finger, sb is halfway between b and st; t is distal to b (Fig. 7 I), b closer to t than sb (ratio distance sb – b / b – t = 3.0). Leg I. Femur 1.77 times as long as patella, tarsus 2.27 times as long as tibia. Arolium undivided, slightly shorter than the simple claws. Chaetotaxy (trochanter to tibia) 0: 9: 8: 12 (Fig. 7 E). Leg IV. Femur and patella 2.91 times as long as wide, tibia 5.03 times as long as wide; basal tactile setae on both tarsal segments, basitarsus 2.95 times as long as wide, telotarsus 9.46 times as long as wide and 2.18 times as long as basitarsus. Arolium undivided, slightly shorter than the claws. Chaetotaxy (trochanter to basitarsus) 1: 3: 6: 10: 10 (Fig. 7 C). Measurements (mm): (length / width or depth in mm and ratios in parentheses calculated with three significant digits). Male holotype. Body length 1.17. Carapace 0.32 / 0.36 (0.88). Palps: trochanter 0.16 / 0.09 (1.7), femur 0.40 / 0.08 (5.0), patella 0.17 / 0.10 (1.7), chela 0.57 / 0.11 (5.18), movable finger length 0.35. Leg I: trochanter 0.11 / 0.08 (1.37), femur 0.23 / 0.05 (4.6), patella 0.13 / 0.05 (2.6), tibia 0.11 / 0.04 (2.75), tarsus 0.25 / 0.02 (12.5). Leg IV: trochanter 0.09 / 0.09 (1.0), femoropatella 0.41 / 0.17 (2.35), tibia 0.29 / 0.06 (4.8), basitarsus 0.13 / 0.04 (3.25), telotarsus 0.28 / 0.03 (9.3). Ecological Remarks. The single specimen of Tyrannochthonius aratu sp. nov. was collected in Morro do Aurélio Cave, situated in the municipality of Iuiú, southwestern Bahia, Brazil. This cave develops within a relatively small limestone outcrop (approximately 2.2 km in length and 1.5 km in width), located about 2.5 km from the larger Serra de Iuiú massif. Morro do Aurélio Cave has a labyrinthine structure, which extends for 1,380 meters and features multiple entrances (primarily vertical shafts or skylights) located at the top of the outcrop. These features facilitate significant air circulation and light penetration, creating microclimatic conditions characterized by extensive dry zones, particularly during the rainy season when evaporation is intensified. Despite this overall dryness, T. aratu sp. nov. was found in a humid aphotic zone far from the cave entrances. The specimens were observed walking on moist sediment beneath limestone blocks in a chamber that receives episodic input of surface runoff during rainfall events. These inputs not only maintain localized humidity but also deposit allochthonous organic matter, such as plant debris, which likely supports the cave’s trophic network. The cave interior is remarkably well preserved, primarily due to the absence of regular human visitation. Archaeological artifacts (including lithic fragments and pottery shards) found within the cave attest to its historical use by ancient South American cultures. The vegetation atop the outcrop remains relatively intact; however, the surrounding external environment is heavily degraded. As in other areas of the Iuiú region, native vegetation has been largely replaced by pasturelands and monocultures. Nevertheless, due to its elevated position atop the outcrop, Morro do Aurélio Cave is likely to be less directly impacted by these external alterations.	en	Guimarães, Lucas, Prado, Guilherme C., Ferreira, Rodrigo L. (2025): Two new species of Tyrannochthonius Chamberlin, 1929 (Pseudoscorpiones: Chthoniidae) from caves in Brazilian semiarid region. Zootaxa 5706 (3): 367-382, DOI: 10.11646/zootaxa.5706.3.3, URL: https://doi.org/10.11646/zootaxa.5706.3.3
