Metaculus tanythrix, Flechtmann, Carlos H. W. & De, Dalva L., 2010

Flechtmann, Carlos H. W. & De, Dalva L., 2010, New taxa in the Eriophyidae (Acari, Prostigmata) from forest trees in southern Brazil, Zootaxa 2337, pp. 18-30 : 26-29

Metaculus tanythrix n. sp.

( Figs. 6 , 7 )

Diagnosis. This is the first species in the genus Metaculus to be reported from ferns (Pteridophyta). It is distinct in having by far the longest prodorsal shield seta (scapular seta, sc) 54–65 µm long (sc range from 6– 35µm in the other species), an eight or nine-rayed empodium (four to six-rayed in the other species) and long second ventral opisthosomal (e) seta, 36–46µm long (e ranges from 7–22µm in other species), reaching basis of third ventral seta (less than half the distance e -f in other species).

Female (n = 6) – Body spindleform, widest at 3–4th dorsal opisthosomal annulus, 184(166–190), 69(60– 69) wide. Gnathosoma projecting down, apical seta (d) 13(11–14); basal seta (ep) 4(3–5); chelicerae 22(16– 22). Prodorsal shield widely rectangular, 36(35–36), 45(42–48) wide, smooth and with a transverse line in between shield tubercles; scapular seta (sc) about one third of entire body length, 61(54–65), 40(35–40). Shield with an anterior rounded lobe, 6(6–8). Legs with all usual setae present. Leg I 28 (27–30); femur 9(8– 11), femoral seta (bv) 11(10–12); genu 3(3–4), genual seta (l”) 34(33–38); tibia 4(4–5), tibial seta (l’) 9(7–11); tarsus 7(6–7), dorsal seta (ft’) 19(18–20), lateral seta (ft”) 26(21–26), unguinal seta (u’) 4(4–5), solenidion blunt, 11(11–12), empodium 7(6–7), 8 or 9-rayed. Leg II 26 (25–27), femur 10(7–10), bv 11(9–12); genu 4(3– 4), l” 11(9–12); tibia 3(3–4); tarsus 6(6–8), ft’ 7(6–8), ft” 26(22–26), u’ 5(4–6), solenidion 13(11–14), empodium 7(5–7), 8 or 9-rayed. Coxae partially with short dashes; coxae I barely touching mesally; coxal seta I (1b) absent; coxal seta II (1a) 19(16–19), 11(10–11) apart; coxal seta III (2a) 38(37–41), 25(19–25) apart. Coxisternal region with 5(5) annuli, microtuberculate. Genitalia 22(21–23) wide, 16(12–16) long; epigynum divided transversally by a curved line and each part by a mediolongitudinal line; anterior two areas with short dashes and posterior areas with two curved, transverse lines; genital seta (3a) 9(9–4). Opisthosoma with smooth dorsal annuli except for the caudal 5(5–6) microtuberculate annuli; ventral annuli entirely microtuberculate. Lateral seta (c2) 45(45–50), on annulus 5–6(5–9). Ventral seta I (d) 70(56–70), 46(42–49) apart, on annulus 19(16–20); ventral seta II (e) 46(36–46), reaching basis of third ventral seta, 26(26–30) apart, on annulus 35(31–35); ventral seta III (f) 23(20–25), 17(15–17) apart, on annulus 58(53–58) or 6(6)th from rear. Total dorsal annuli 31(30–32); total ventral annuli 64(59–64). Caudal seta (h2) 31(27–33); accessory seta (h1) 7(6–8).

Male (n = 2) Smaller than female, 151, 55 wide. Gnathosoma: d 9, ep 3; chelicerae 16. Prodorsal shield 30–33, 40–42 wide; sc 37–40, 31–33 apart. Frontal lobe 4. Legs: leg I 26; femur 8–9, bv 9–11; genu 4, l” 28– 31; tibia 4, l’ 8–9; tarsus 6, ft’ 17–18, ft” 19–21, u’ 3–4, solenidion 10, empodium 6, 8 or 9-rayed. Leg II 23– 25; femur 7–8, bv 9–10; genu 3, l” 10–11; tibia 3–4; tarsus 5–6, ft’ 7, ft” 20, u’ 3, solenidion 10–11, empodium 5–6, 8-rayed. Coxae: 1b missing; 1a 13–15, 8–10 apart; 2a 27–30, 19–21 apart. Coxisternal area with 6 annuli. Genitalia: 11–12 wide, 14–16 long; 3a 9. Opisthosoma: c2 39–40, on annulus 4; d 48–53, 30– 33 apart, on annulus 12; e 28, 20 apart, on annulus 23; f 21, 16 apart, on annulus 43, or 6th from rear. Total dorsal annuli 28; total ventral annuli 49; h2 33–41, h1 4–5.

Type material. Female holotype and 54 female and 2 male paratypes, from Dicksonia sellowiana Hook. (Dicksoniaceae) , “xaxim”, a tree fern, Jardim Botânico, Curitiba, Paraná, Brazil, 25º26’S and 49º14’W, August 2008, collected by Dalva L. de Queiroz, on 10 microscopic preparations in the collection of Departamento de Entomologia e Acarologia, ESALQ – Universidade de São Paulo, Piracicaba, São Paulo, Brazil.

Relation to host. Vagrant on fronds; no apparent damage.

Etymology. The specific designation tanythrix comes from the Greek, meaning long- haired and refers to the long scapular and ventral setae.

Figures

FIGURE 6. Metaculus tanythrix n. sp., female. D—dorsal aspect; IG—internal genital structures; V—ventral aspect.

FIGURE 7. Metaculus tanythrix n. sp. GM—male genitalia; L—antero lateral aspect of female; L 1 — leg I; L 2 — leg II.