taxonID	type	description	language	source
882A93D5978E53AA8973E76B0BBCD7B3.taxon	diagnosis	Diagnosis. Small Hypogastruridae with a fusiform habitus. White species, without eyes, post-antennal organ, retinaculum and furca. Tibiotarsi with 16 – 20 setae, including 1 or 2 knobbed or pointed tenent hairs. Claws with or without teeth. Setal pattern of type I, with mesosetae more or less serrated and sensory setae sometimes longer and smooth (Thibaud et al. 2004).	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
57B6F3D20AC154CCA47DAFA77356E30B.taxon	description	Figs 3, 4, 5, 6, 7, 8, 17 A, Table 2	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
57B6F3D20AC154CCA47DAFA77356E30B.taxon	diagnosis	Diagnosis. Colour white, without pigment. Eyes, PAO, furca and retinaculum absent. Labrum with 4 / 554 setae. Four anterior setae on labrum thickened. Ant IV with simple apical vesicle and 4 subapical subglobular sensilla. VT with 4 + 4 apical setae. Tibiotarsi with 2 knobbed tenent hairs. Claws with strong internal subapical tooth, empodium absent. Two small anal spines present. Setae m 1, m 4, and m 5 on Abd IV present.	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
57B6F3D20AC154CCA47DAFA77356E30B.taxon	description	Description. Body. Length 0.76 mm on average (n = 8, maximum length 0.84 mm). Habitus and buccal cone typical of genus Acherontiella. Eyes, PAO, retinaculum, and furca absent. Body fusiform, covered by serrate mesosetae; two small anal spines present (Fig. 17 A). Colour white, without traces of pigment. Cuticular granulation rather uniform. Antennae. Antennae slightly shorter than head, 0.134 mm and 0.165 mm, respectively (Fig. 3 A). Length of Ant I: II: III and IV (Ant III – IV fused dorsally) in holotype as 0.024: 0.026: 0.083 mm, respectively. All setae on Ant I – II serrate. Ant I with 7 setae; Ant II with 12 setae. Ant III and IV fused dorsally, intersegmental suture on ventral side well marked, 23 dorsal and 26 ventral setae, all normal, smooth (lateral setae longer than others). Ant IIIO with 2 central short and curved rods (microsensilla) flanked by 2 long guard sensilla of very characteristic constitution (Fig. 3 B) (Deharveng and Díaz 1984); small ventrolateral microsensillum in a ventral pit. Ant IV with a protrusible simple ventroapical vesicle (Fig. 5 B), 4 subglobular sensilla – 2 ventral (lateroexternal) and 2 dorsal (1 lateroexternal, 1 laterointernal) (Fig. 5 A, B), dorsoexternal subapical ms and apical os near external sensilla (see D’Haese 2003). Head. Eyes and PAO absent. Setal formula of labrum 4 / 5, 5, 4, four anterior labral setae thickened (Figs 4 B, 5 C). Labium and labial triangle as in Fig. 4 C, with 5 main papillae (A – E), 6 proximal smooth setae, 4 basomedial and 5 basolateral smooth setae. Maxillary outer lobe with 3 sublobal hairs (Fig. 4 E). Left mandible with 3 teeth and right mandible with 4 teeth (Fig. 4 D). Legs. Legs I – III with normal setae, tibiotarsi with 2 knobbed tenent hairs (Fig. 5 F). Setal pattern as in Fig. 6 A – C. Leg I: coxa with 3 setae, trochanter with 5 dorsal setae, femur with 13 setae, Tib with 19 setae, including 2 knobbed apical tenent hairs. Leg II: coxa with 8 setae, trochanter with 5 setae, femur with 13 setae, Tib with 19 setae, including 2 knobbed apical tenent hairs. Leg III: coxa with 7 setae, trochanter with 4 setae, femur with 11 setae, Tib with 18 setae, including 2 knobbed apical tenent hairs; Claw slender, internal edge with strong subapical tooth (Fig. 5 E); empodium absent; pretarsus with 2 setae (1 internal, 1 external) shorter than half of the length of claw (Fig. 6 D – F). Abdomen. Ventral tube with 4 + 4 apical setae. Retinaculum and furca absent. 2 small anal spines present. Ratio ASp: claw III = 0.36: 1 Setal pattern. Dorsal setal pattern generally of type I with mesosetae (after Jordana et al. 1997). Setae on head and body serrate (Fig. 5 D), sensilla longer and smooth. Head. Dorsal setal pattern as in Fig. 3 C. Seta a 0 often present (absent in some specimens); d 1 – d 5; sd 3 – sd 5 (sd 1 and sd 2 absent); v 1 [v 2 absent]; c 2 – c 5 (c 1 absent); p 1 – p 5; oc 1 – oc 2 (oc 3 absent). Ventral setal pattern as in Fig. 4 A, with smooth setae. Thorax. Dorsal setal pattern as in Fig. 7. Position of ss in p row of setae on Th II – III is 4 and 4, respectively. Th I with 3 + 3 setae (m 1, m 3 and m 4); Th II and III with 3 rows of setae – a: 4 + 4 as a 1, a 2, a 4 and a 5 [a 3 absent]; m: 3 + 3 between m 6 (s) as m 1, m 4 and m 5 [m 2 and m 3 absent]; p: 3 + 3 between p 4 (s) as p 1 – p 3. Thoracic sterna without setae. Abdomen. Dorsal setal pattern as in Fig. 8 A, ventral setal pattern as in Fig. 8 B. The position of ss in p row on Abd I – V as 5, 5, 5, 4, 3, respectively. Abd I – III with 2 rows of setae – a: 5 + 5 as a 1 – a 5; p: 4 + 4 between p 5 (s) as p 1 – p 4. Abd IV with 3 rows of setae – a: 4 + 4 as a 1, a 2, a 4 and a 5 [a 3 absent]; m: 3 + 3 as m 1, m 4 and m 5 [m 2 and m 3 absent]; p: 3 + 3 between p 4 (s) as p 1 – p 3. Abd V with 2 rows of setae – a: 3 + 3 as a 1 – a 3; p: 2 + 2 between p 3 (s) as p 1 and p 2.	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
57B6F3D20AC154CCA47DAFA77356E30B.taxon	etymology	Etymology. The new species is dedicated to Javad Nezamdoost, the founder and former director of the Cave and Speleology Association (ISCA) of Iran who has made a lot of efforts in exploration and protection of Iranian caves.	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
77ACE6A0D884517788655CCD1C98B4AF.taxon	description	Figs 11, 12, 13, 14, 15, 16, 17 B, Table 2	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
77ACE6A0D884517788655CCD1C98B4AF.taxon	diagnosis	Diagnosis. Eyes, PAO, furca, and retinaculum absent. Labrum with 4 / 554 setae, anterior row with 2 medial apically dentate spine-like setae. Ant IV with simple apical vesicle and 4 subapical globular sensilla. VT with 4 + 4 apical setae. Tibiotarsi with 2 knobbed tenent hairs. Claws with strong subapical internal tooth, empodium absent. Anal spines absent. Th I with setae m 1 and m 4.	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
77ACE6A0D884517788655CCD1C98B4AF.taxon	description	Description. Body. Length 1.0 mm on average (n = 9, maximum length 1.18 mm). Habitus and buccal cone typical of the genus Acherontiella. Eyes, PAO, retinaculum, and furca absent. Body fusiform, covered by serrate mesosetae (Fig. 13 D), anal spines absent. Colour white, without traces of pigment. Cuticular granulation rather uniform. Antenna e. Antennae slightly shorter than head, 0.18 mm and 0.20 mm, respectively (Fig. 11 A). Length of Ant I: II: III and IV (dorsally fused) as 0.034: 0.036: 0.11 mm, respectively. All setae on Ant I – II slightly serrate. Ant I with 7 setae; Ant II with 11 setae. Ant III and IV dorsally fused, intersegmental suture on ventral side well marked, 26 dorsal and 25 ventral setae, all normal, smooth (lateral setae longer than other setae). Ant IIIO with 2 central short and curved rods (microsensilla) flanked by 2 long guard sensilla of characteristic constitution (Deharveng and Díaz 1984) (Fig. 11 B), a small ventrolateral microsensillum in a ventral pit. Ant IV with a protrusible ventroapical simple vesicle (Fig. 13 A), 4 globular sensilla (Fig. 13 B) – 2 dorsal (1 lateroexternal, 1 laterointernal) and 2 ventral (both lateroexternal), dorsoexternal subapical ms and apical os near external sensilla (see D’Haese 2003). Head. Eyes and PAO absent. Setal formula of labrum 4 / 5, 5, 4, two medial setae in anterior row on labrum thickened as spines and apically dentate (Figs 12 B, 13 C). Labium and labial triangle as in Fig. 12 C, with 5 main papillae (A – E), 6 proximal smooth setae, 4 basomedial and 5 basolateral smooth setae. Maxillary outer lobe with 1 sublobal hair (Fig. 12 E). Left mandible with 3 teeth and right mandible with 4 teeth (Fig. 12 D). Legs. Legs I – III with normal setae, tibiotarsi with 2 knobbed tenent hairs (Fig. 13 E). Setal pattern as in Fig. 14 A – C. Leg I: coxa with 3 setae, trochanter with 6 setae, femur with 12 setae, Tib with 18, including 2 knobbed apical tenent hairs. Leg II: coxa with 8 setae, trochanter with 6 setae, femur with 12 setae, Tib with 18, including 2 knobbed apical tenent hairs. Leg III: coxa with 7 setae, trochanter with 6 setae, femur with 11 setae, Tib with 17, including 2 knobbed apical tenent hairs; claw slender (Fig. 14 D – F), internal edge with strong subapical tooth (Fig. 13 F); empodium absent. Pretarsus with 2 setae (1 internal, 1 external), both reaching the half length of internal lamella. Abdomen. Ventral tube with 4 + 4 setae. Retinaculum and furca absent. Anal spines absent, substituted by 2 serrate setae (Fig. 17 B). Setal pattern. Dorsal setal pattern generally of type I with mesosetae (after Jordana et al. 1997). Setae on head and body slightly serrate, sensory setae longer and smooth. Head. Dorsal setal pattern as in Fig. 11 C. Seta a 0 present; d 1 – d 5; sd 3 – sd 5 (sd 1 and sd 2 absent); v 1 – v 2; c 2 – c 5 (c 1 absent); p 1 – p 5; oc 1 – oc 2 (oc 3 absent). Ventral setal pattern as in Fig. 12 A, all setae smooth. Thorax. Dorsal setal pattern as in Fig. 15. Position of ss in p row on Th II – III is 4 and 4, respectively. Th I with setae m 1 and m 4 [m 2 and m 3 absent]; Th II and III with 3 rows of setae – a: 4 + 4 as a 1, a 2, a 4 and a 5 [a 3 absent]; m: 3 + 3 between m 6 (s) as m 1, m 4 and m 5 [m 2 and m 3 absent]; p: 2 + 2 between p 4 (s) as p 1 and p 2 [p 3 absent]. Thoracic sterna without setae. Abdomen. Dorsal setal pattern as in Fig. 16 A. Position of ss in p row on Abd I – V is 5, 5, 5, 4 and 3, respectively. Abd I – III with 2 rows of setae – a: 5 + 5 as a 1 – a 5; p: 4 + 4 between p 5 (s) as p 1 – p 4. Abd IV with 3 rows of setae – a: 3 + 3 as a 1, a 2 and a 4 [a 3 absent]; m: 1 + 1 (or 2 + 2) as m 4 (m 5) [m 1, m 2 and m 3 absent]; p: 3 + 3 between p 4 (s) as p 1 – p 3. Abd V with 2 rows of setae – a: 3 + 3 as a 1, a 3 and a 4 [a 2 absent]; p: 2 + 2 between p 3 (s) as p 1 – p 2. Ventral abdominal setal pattern as in Fig. 16 B.	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
77ACE6A0D884517788655CCD1C98B4AF.taxon	etymology	Etymology. The new species is dedicated to our colleague and friend professor José G. Palacios-Vargas (Universidad Nacional Autónoma de México) for his immense contribution to taxonomy of soil and subterranean Collembola.	en	Mehrafrooz Mayvan, Mahmood, Kováč, Ľubomír (2025): Two new species of the genus Acherontiella (Collembola, Hypogastruridae) from caves of the Alborz and Kopet Dagh mountains in Iran. ZooKeys 1255: 1-25, DOI: 10.3897/zookeys.1255.164170
