(Figures 39–45)
Diagnosis. Female dorsal shield smooth. Dorsal setal pattern 10 A: 9 B. Seventeen pairs of dorsal setae, Z 5 serrated. Seta j 3 much longer than j 1 and similar in length to s 4. Seven pairs of dorsal solenostomes. Peritremes reaching seta j 1. Sternal shield with three pairs of setae and posterior margin straight. Ventrianal shield smooth, with three pairs of setae and pre-anal pores crescentic. Calyx of spermatheca saccular. Fixed digit in the chelicerae with nine teeth; movable digit three–toothed. Genu II with seven setae. Leg IV with three long macrosetae; msti and msta similar in length and shorter than msge. Male ventrianal shield anteriorly convex; five pairs of pre-anal setae. Spermatodactyl L-shaped.
FEMALE (Figures 39–43) (three females measured)
Dorsal surface. Dorsal shield smooth, 418 (418–427) long, 222 (222–252) wide. Seventeen pairs of smooth and acute setae, except Z 5 serrated. Setae j 1 and j 3 straight and oriented forward in live specimens. Seta j 1 35 (34– 35), j 3 52 (49–52), j 4 9 (9–10), j 5 8 (7–8), j 6 10 (10–12), J 2 11 (11–12), J 5 8 (7–8), z 2 19 (19–21), z 4 18 (17–20), z 5 9 (8–9), Z 1 14 (14–15), Z 4 72 (70–75), Z 5 99 (97–100), s 4 54 (54–56), S 2 18 (18–19), S 4 15 (15–16), S 5 13 (12– 13), r 3 20, R 1 20 (20–22). Seven pairs of solenostomes; gd 9 anteromedial to S 5. Distance gd 9 – S 5 17; distance gd 9 –Z 5 24. Peritremes fully developed, reaching setae j 1.
Ventral surface. Sternal shield smooth, with three pairs of setae. Distance st 1 –st 3 80 (80–84), distance st 2 –st 2 85 (85–86). Seta st 4 on metasternal platelets. Posterior margin of shield straight. Genital shield 87 (87–100) wide. Ventrianal shield smooth, with two lateral areas of muscle attachments on the posterior margin, at the level of anus. Anterior part wider than posterior, 136 (136–146) long, 109 (105–109) wide at level of ZV 2. Three pairs of pre-anal setae; crescentic and close pre-anal pores, distance 23 (23–24). Four pairs of setae around the shield, JV 5 48 (47– 48).
Chelicerae. Fixed digit with about nine teeth; movable digit with three teeth.
Insemination apparatus. Calyx saccular, major duct narrow, atrium C-shaped and prominent.
Legs. Genu II with seven setae; 2 – 2 /0, 2/ 0–1. Macroseta on genu I not very distinctive from other setae in the segment, 24 (24–26) long, macroseta on genu II 35, genu III 32 (32–36). Leg IV with three long and blunt macrosetae; msge 62 (62–64), msti 54 (52–54), msta 51 (51–52).
MALE (Figures 44–45): (two males measured)
Dorsal surface. Dorsal shield smooth, 348 (346–350) long, 216 (212–220) wide. Nineteen pairs of smooth and acute setae, except for Z 4 and Z 5 which are slightly serrated. Seta j 1 29 (27–30), j 3 41 (40–42), j 4 8 (7–8), j 5 6 (5– 6), j 6 12 (11–12), J 2 12, J 5 10 (9–10), z 2 14 (13–14), z 4 17, z 5 8, Z 1 15 (14–15), Z 4 56 (55–57), Z 5 74 (73–74), s 4 47 (46–48), S 2 17 (16–18), S 4 13 (12–13), S 5 12 (11–12), r 3 19 (18–20), R 1 17 (15–18). Seven pairs of dorsal solenostomes. Peritremes extending almost to bases of setae j 1.
Ventral surface. Ventrianal shield subtriangular with anterior margin convex, 152 (150–154) long, 179 (178– 180) wide at level of anterior corners. Surface smooth with scant anterior striae, bearing five pairs of pre-anal setae, four pairs of poroids and a pair of crescentic pores posteromesad to JV 2. Two prominent lateral areas of muscle attachments on the anterior corners of the shield. Seta JV 5 40 (39–40).
Chelicerae. Fixed digit apparently with eight teeth; movable digit unidentate. Spermatodactyl L-shaped, with a well-developed lateral projection.
Legs. Leg IV with three blunt macrosetae; macroseta on genu 50 (49–50), tibia 38 (37–38) and basitarsus 47 (46–47).
Type material. One female holotype, two female paratypes and two male paratypes on Saxegothaea conspicua. Tinquilco Lake near Pucón (Chile); 39 º 10 '09" S, 71 º 43 ' 33 " W; 814 m asl; 6 January 2013. Holotype and some paratypes were deposited at Museo Nacional de Ciencias Naturales, Madrid, Spain (MNCN). Reference number of holotype: MNCN 20.02 / 17391; 1 female paratype MNCN 20.02 / 17392; 2 male paratypes (MNCN 20.02 / 17393; MNCN 20.02 / 17394).
Etymology. The specific name caliginosus means "gloomy" or "foggy" and refers to the humid and dark forest where the mite was collected in Chile.
Comments. This species belongs to the nicola subgroup of the obtusus species group (Chant & McMurtry, 2004) and is most similar to A. grandiporus. It can be differentiated by the absence of hypertrophied pre-anal pores, by the largest length of seta j 3 related to j 1 and the insertion of seta JV 2 relative to the pre-anal pores. In addition, A. caliginosus has only nine teeth on fixed digit and the male shows five pairs of pre-anal setae.