Amazonacarus paraensis Vázquez, Araújo & Feres, 2014

Vázquez, Ma. Magdalena, Araújo, Marcel Santos De & Feres, Reinaldo José Fazzio, 2014, A new genus and two new species of Opilioacaridae (Acari: Parasitiformes) from Amazonia, Brazil with a key to world genera, Zootaxa 3814 (2), pp. 151-176 : 162-168

Amazonacarus paraensis Vázquez, Araújo & Feres n. sp.

( Figs. 22–34 , 52 )

Diagnosis. Preanal segment XVII with 6–4 dorsal setae (6 in females, 4 in males) plus a pair of latero-ventral setae ( Figs. 44–46 ) Palp tarsus in adults with 12 foliate (d) setae; palp tibia with 24 long serrate and thin setae ( Fig. 40–41 , 52 ). Females ovipositor ( Fig. 33–34 ) with internal membrane forming various digit-like, large projections. Females with 4 large, fine and acute eugenital setae. Pregenital and genital areas in males with, respectively, 15 and 15 short, acute and thick setae.

Description. Based on observation on 2 females and 6 males.

Gnathosoma . Chelicerae ( Fig. 22 ). Basal segment with 1 seta, Fixed digit with 3 setae. Dorsal and antiaxial lyrifissures generally well developed. Movable digit with 2 teeth and terminal hook, fixed digit with 1 well developed tooth and 2 ridges in addition to terminal hook. Movable digit with 5–6 ventral denticles (serrula).

Subcapitulum ( Figs. 23–24 ). Adults with 4 pairs of paralabial setae; pl1 small, conical; With’s organ (pl2) membranous; rutella (pl3) each with 1 row of 5 teeth, inserted dorso- laterally; pl4 very small, inserted dorsally on subcapitulum. In addition, 4 circumbuccal (cb), and 11–14 median and subcapitular setae (includes vm (in part) lvm, ldm, vp and lvp setae). Sexual dimorphism present, females with larger subcapitulum and more setae on subcapitulum (14) than males (11). Lateral lips with distinct channels.

Palps ( Figs. 25–29 ). Trochanter with 5–6 ribbed, tapering subequal (r - type) setae; femur with 13 papilliform (p - type), and 11 r - type setae; genu with 7 p - type and 31 r - type. Tibia with 47 r - type setae and 24 long, serrate and acute (= s - type) setae, plus two sensillae (ss); four of the s - type setae elongate, 2 of them reaching mid-point of the tarsus. Tarsus with 10 foliate (d) setae, 10 v setae,15 ch setae, 3s, and 4 sm in adults.

Idiosoma. Anterior dorsal shield of adults with numerous papilliform setae and 2 pairs of eyes. Remaining idiosoma with many dorsal lyrifissures arranged in transverse rows. Preanal segment in female with 6 dorsal setae, male with 4, both with a pair of lateroventral setae. Each anal valve in female with 12, in male with 9 setae.

Sternitogenital region ( Figs. 31–32 ). Each sternal verruca in adults with 1 composite and 2–3 truncate, slightly shorter setae. Remaining sternal area with 1 pair of basally stout, tapering setae plus 3 pairs of stout, blunt setae of similar lengths. Pregenital capsules in males and females with 3–4 ribbed tapering setae plus 1 composite seta. Pregenital and genital area in male with, respectively, 15 and 15 short, thick, acute setae. Both groups of setae on small papillae. Pregenital and genital area in female without setae.

Ovipositor ( Figs. 33–34 ). Large. with 4 long, serrate, fine eugenital setae, emerging from small tubercles. Internal membrane forming various digit-like large projections. When evaginated, distal portion with many hexagonal cell-like structures almost at top. Structures seemingly at different positions depending upon whether the ovipositor is evaginated or invaginated.

Legs. Tarsus II with dorsal bifurcate seta and 2 smooth sensilla resembling solenidia.

Measures. Idiosoma length 1287, width 1096. Palps: trochanter 60–110; femur 112–212; genu 87–140; tibiotarsus 172–230. Rutella: 82–147. Chelicera: movable digit 55–107; median segment 157–285; basal segment 140–162. Legs. Leg I, absent. Leg II: trochanter I 152, femur 407, genu 207, tibia 220, basitarsus 270, telotarsus 237, acrotarsus 65. Leg III: trochanter I 92 –105, trochanter II 68 –70, femur 176–201, genu 120–142, tibia 125–142, basitarsus 156–188, telotarsus 156–168, acrotarsus 49–73. Leg IV: trochanter I 150–219, trochanter II 99 –176, femur 331–565, genu 198–322, tibia 180–384, basitarsus 218–343, telotarsus 266–302, acrotarsus 89.

Collection information. Holotype female. BRAZIL, Pará, Santarém, 11km SE of Santarém, coll. Lehtinen, P., 7.IX.1983, ex thick layer of litter on root turf in primary, forest. Paratypes, same data of holotype.

Deposition of types. Holotype female at ZMT. Paratypes at ZMT and DZSJRP.

Etymology. The specific name is derived from the region were the exemplars were collected, Pará state.

Description of the immatures. Based on deutonymphs ( A. setosus = 2, A. paraensis = 4) and tritonymphs ( A. setosus = 4, A. paraensis = 1). No larvae or protonymphs were available.

The number of setae on the main parts of the body gradually increases in each instar ( Table 1 ).

Chelicera (Figs. 35–37). Setation and denticles same as adults.

Subcapitulum (Figs. 38–39). On hypostome, DN with 6 (rarely 7 in A. setosus ) subcapitular setae plus 4 circumbuccal (cb) setae. TN with 10 subcapitular setae (rarely 11 in A. paraensis ) plus 4 cb. All paralabial setae present in these instars.

Palps ( Figs. 40–41 ). Tarsus in DN with 6 foliate setae, TN 8 (adults with 10 foliate serrate setae plus 16 medium-large fine, serrate setae on palp-tibia. In adults there are 4–6 large serrate setae plus 22 medium-large sized, fine, serrate setae.

Sternitogenital region ( Figs. 42–43 ). Sternal verrucae with 2+1 setae (rarely 3+ 1 in A. paraensis ). Sternal area between sternal and genital verrucae in DN and TN with 1 pair of composite setae and 3 pairs of large, serrate setae. Genital capsule with 2+1 setae in DN (rarely 3+ 1 in A. paraensis ) and 3+ 1 in TN. In two exemplars of A. paraensis TN, 2 small setae on genital area. A tritonymph of A. paraensis presents setae on the genital area, probably indicating a developing male, because females have no setae in this region.

Preanal segment ( Figs. 44–46 ) presents variation in crescent setae according to instar. DN with 3 setae dorsally plus 1 pair of lateroventrals on both species, TN with 3 setae dorsally (4 in A. setosus ) plus 1 pair of lateroventrals as in males.

Each anal plate in DN with 6–7 setae in A. paraensis and 8 setae in A. setosus ; TN of both species with 8 setae.

Figures

FIGURES 22 – 24. Amazonacarus paraensis n. sp. 22, lateral view of male chelicerae and details of denticles (arrow: ventral denticles). Ventral view of hypostome: 23, female; 24, male.

FIGURES 25 – 26. Amazonacarus paraensis n. sp. Ventral view of (25) male and (26), female palp tibiotarsus. Arrows indicate the unique length of this setae group in Opilioacaridae.

FIGURES 27 – 29. Amazonacarus paraensis n. sp. Dorsal (left) and ventral (right) view of genu (27); femur (28); trochanter (29).

FIGURES 30. Amazonacarus paraensis n. sp. 30, dorsal view of female XVIII segment and anal segment (moulting).

FIGURES 31 – 32. Amazonacarus paraensis n. sp. Ventral view of sternitogenital region: 31, female (arrow points to genital setae); 32, male.

FIGURES 33 – 34. Amazonacarus paraensis n. sp. 33, Ventral view of evaginated ovipositor (arrow points ovipositor tip). 34, ventral view of female sternitogenital area and invaginated ovipositor (arrow points ovipositor tip).

FIGURES 51 – 53. 51, Caribeacarus panamensis. 52, Amazonacarus paraensis n. sp. 53, Amazonacarus setosus n. sp. Showing the group of setae s-type which are very large in A. setosus, but not in other species.

FIGURES 44 – 46. Amazonacarus setosus n. sp. Dorsal view of preanal segment: 44, tritonymph; 45, deutonymph. Amazonacarus paraensis n. sp. 46, dorsal view of deutonymph preanal segment.

FIGURES 40 – 41. Amazonacarus setosus n. sp. Lateral view of palps: 40, tritonymph; 41, deutonymph.

FIGURES 42 – 43. Amazonacarus setosus n. sp. Ventral view of sternitogenital region: 42, tritonymph; 43, deutonymph.