Tetra theobromae, Rodrigues, Daniela F. S., Navia, Denise, Oliveira, Anibal R., Ferragut, Francisco & Flechtmann, Carlos H. W., 2017

Rodrigues, Daniela F. S., Navia, Denise, Oliveira, Anibal R., Ferragut, Francisco & Flechtmann, Carlos H. W., 2017, Two new eriophyoid mite species (Trombidiformes: Eriophyoidea) from the cocoa tree, and a note on Shevtchenkella biseta (Nalepa), Zootaxa 4237 (1), pp. 112-130 : 123-126

Tetra theobromae n. sp. Rodrigues, Navia & Oliveira

( Figs. 3–4 )

Diagnosis. A Tetra species presenting dorsal annuli bearing thin elongated microtubercles occupying posterior 3/4 of annuli; posterior margin of dorsal annuli with sharp subtriangular indentations, mainly in sublateral area where these are arranged in longitudinal rows; prodorsal shield design with a pair of two curved, longitudinal lines, touching medially and anteriorly but posteriorly divergent; 6-rayed empodium; coxisternal region finely granulated; coverflap medially emarginated in posterior margin and with 12–16 longitudinal or radiating lines.

FEMALE (n=14). Body fusiform, 130 (130–159), 50 (46–56) wide. Gnathosoma projecting downwards; pedipalp coxal seta (ep) 4 (2–4); dorsal pedipalp genual seta (d) 4 (4–5), simple; subapical pedipalp tarsal seta (v) 2 (2); cheliceral stylets 16 (16–21). Prodorsal shield semicircular, wider than long, with a curved posterior margin, 24 (23–25), 41 (39–41) wide; short, broad-based frontal lobe, apically curved, 3 (3–4), 11 (9–11) wide; area laterad to prodorsal shield granulated. Shield design of two pairs of curved irregular lines (in position of admedian lines) which touch on anterior shield (1/3 anterior); anterior line is shorter and extends laterally outwards; tubercles and scapular setae (sc) on rear shield margin, sc 21 (19–23), sc tubercles robust and broad-based, 23 (19–24) apart. Legs with all segments and usual setae present. Leg I 21 (21–24); femur 7 (7–9), basiventral femoral seta (bv) 7 (7–9); genu 4 (3–5), antaxial genual seta (l") 16 (15–19); tibia 5 (5–6), paraxial tibial seta (l') 5 (4–6); tarsus 5 (5), antaxial fastigial tarsal seta (ft”) 17 (15–18), paraxial fastigial tarsal seta (ft’) 14 (13–16), unguinal seta (u’) 4 (3– 4), tarsal solenidion (ω) 6 (6), apically slightly expanded; empodium 5 (5–6), undivided, symmetrical, 6-rayed. Leg II 20 (19–21); femur 7 (6–8), bv 8 (7–10); genu 3 (3–4), l" 7 (5–7); tibia 5 (4–5); tarsus 5 (4–5), ft" 16 (15–17), ft' 5 (4–6), u’ 3 (3–4), ω 6 (5–6) as in leg I; empodium 5 (4–5), 6-rayed, as in leg I. Coxisternal region finely microtuberculated. Anterolateral seta on coxisternum I (1b) 5 (5–8), 6 (6–8) apart; proximal seta on coxisternum I (1a) 12 (11–15), 7 (6–7) apart; proximal seta on coxisternum II (2a) 27 (27–31), 17 (17–20) apart; prosternal apodeme 6 (5–6); coxigenital region with 6 (5–7) annuli, microtuberculated. External genitalia 11 (9–13), 19 (18– 20) wide, coverflap semicircular, posterior margin medially emarginated, anteriorly with two curved w-shaped lines finely microtuberculated, posteriorly with 14 (12–16) longitudinal or radiating lines; proximal seta on coxisternum III (3a) 9 (8–11). Internal genitalia, anterior genital apodeme trapezoidal; oblique apodeme distinct, forming an inverted V-like figure, with bent arms laterally directed; spermatheca spherical or slightly elongated, directed posteriad or laterad; spermathecal duct short, ~ 1 long, tube like, directed posteriad (average angle of 120° between spermathecal apparatus and longitudinal bridge); longitudinal bridge ~ 8 long, postspermathecal part of longitudinal bridge reduced. Opisthosoma. Dorsal opisthosoma with wide furrow, except for first annulus with broad median ridge; dorsal annuli bearing thin elongated microtubercles (occupying 3/4 of annuli posteriorly) aligned in distinct transversal row; posterior margin of dorsal annuli with sharp subtriangular indentations, mostly on lateral ridges, arranged in two sub-lateral longitudinal rows, extending from 3rd annulus along whole opisthosoma (except for 5–6 posterior annuli); 21 (21–24) dorsal annuli; 50 (45–54) ventral annuli with slightly elongated microtubercles on posterior margin, more elongated on last annuli posterior to ventral seta f. Lateral seta c2 18 (18–22), on ventral annulus 3 (2–5); ventral seta d 36 (32–36), on annulus 14 (13–16), 27 (27–33) apart; ventral seta e 6 (5–8), on annulus 27 (26–32), 14 (14–19) apart; ventral seta f 14 (12–14), on annulus 46 (41–50), 15 (13–16) apart; caudal seta h2 39 (35–40); accessory seta h1 2 (2).

MALE (n=1). Smaller than female. All measurements of male are given in Table 1. External genitalia 10, 13 wide; 3a 7, area flanked by 3a and posterior to gonopore finely granulated, eugenital setae seen on anterior median area.

Type material. Sixteen specimens intercepted at the plant quarantine station " Estação Quarentenária de Germoplasma Vegetal, Embrapa Recursos Genéticos e Biotecnologia ", Brasília , DF, Brazil, from Theobroma cacao L. ( Malvaceae ) seedlings, originated from the germplasm bank “ Centro Agronómico Tropical de Investigación y Enseñanza ( CATIE)”, Turrialba, Costa Rica, on 13 June 2013, collected by F. J. Carvalho and H.M.C. Rocha. Female holotype (red labelled slide, indicated by a red ring and in the specimen map at the right side label) and five paratypes (5 females) on three slides deposited in the Acarological Collection at "Embrapa Recursos Genéticos e Biotecnologia", Brasília , DF, Brazil . Six paratypes (5 females and 1 male) in four slides deposited in the Acarological Collection at Universidade Estadual de Santa Cruz ( UESC), Ilhéus, BA, Brazil . Four paratypes (4 females) in four slides deposited in the Acarological Collection at “ Departamento de Entomologia e Acarologia, Universidade de São Paulo, Escola Superior de Agricultura ‘ Luiz de Queiroz’ ( ESALQ)", Piracicaba , SP, Brazil .

Relation to host. A vagrant species found on young leaves, no symptoms observed.

Etymology. The specific designation “ theobromae ” is derived from the genus name of the type host plant, Theobroma , in the genitive possessive case.

Remarks. The new Tetra species is very distinct from T. coimbatorensis Mohanasundaram, 1994 and T. striata Navia, 1999 , the only two species in this genus associated with a Malvaceae host plant. Although Tetra theobromae n. sp. is similar to T. striata in the dorsal annuli bearing thin elongated microtubercles, they differ in distribution in the two species (microtubercles distributed along entire dorsal annuli in T. theobromae n. sp.; absent in the median area between dorso-median ridges in T. striata , except for the first 2–3 and last 9–11 annuli); in T. coimbatorensis the dorsal opisthosomal annuli are smooth. The new species has sharp subtriangular annuli indentations in the posterior margin of the dorsal annuli, mostly arranged in sublateral longitudinal rows; these were not observed in T. striata and T. coimbatorensis . Other remarkable differences are: prodorsal shield ornamentation with median line absent and two irregular curved lines in the position of admedian lines in T. theobromae n. sp. (median line present and connected by transversal lines to admedian ones, bearing closed cells in T. striata ; smooth in T. coimbatorensis ); the number of empodium rays (6 rays in T. theobromae n. sp.; 5 rays in T. striata ; 4 rays in T. coimbatorensis ); the coverflap ornamentation (longitudinal or radiating lines in T. theobromae n. sp.; smooth in T. striata ; only longitudinal lines in T. coimbatorensis ).

Tetra theobromae n. sp. also differs from the other four Neotropical species of this genus. It differs from T. tuttlei Keifer, 1975 and T. gibbosa Flechtmann, 2014 (in Ballari et al. 2014) in the dorsal opisthosomal annuli (with thin, elongated microtubercles occupying 3/4 of the annuli posteriorly in T. theobromae n. sp.; with beadlike acuminate microtubercles on rear annulus margins in T. tuttlei ; smooth in T. gibbosa ); the prodorsal shield ornamentation pattern (two curved irregular lines in position of admedian lines in T. theobromae n. sp.; median lines present on 2/5 area enclosed by admedians, admedians complete, longitudinal lines are linked by transversal lines forming cells in T. tuttlei ; and with dorsal elevations or callosities, delimited by mainly longitudinal lines and one transversal line in T. gibbosa ); and the number of empodial rays (6 rays in T. theobromae n. sp.; 8 rays in T. tuttlei ; and 4 rays in T. gibbosa ).

Tetra indiciva Flechtmann, 2009 , described from Brazil, presents prominent groups of pointed wax-like secreting structures on the two lateral ridges of the dorsal opisthosoma. In the new species we observed the presence of sharp subtriangular indentations mostly arranged in longitudinal rows on the area of the lateral ridges. It is possible that these structures are homologous. Regarding other traits, these species are very distinct: in T. indiciva the dorsal annuli are not microtuberculated (thin elongated microtubercles in T. theobromae n. sp.); in T. indiciva the prodorsal shield lacks lines (curved lines in T. theobromae n. sp.); and T. indiciva presents a 4-rayed empodium (6-rayed in T. theobromae n. sp.).

Tetra theobromae n. sp. differs from T. eldoradensis Keifer, 1966 in the prodorsal shield shape (semicircular, wider than long in T. theobromae n. sp.; subtriangular, at least as wide as long in T. eldoradensis ); frontal lobe (short, not extending over gnathosomal base in T. theobromae n. sp.; prominent extending over gnathosomal base in T. eldoradensis ), and ornamentation (median line absent, two irregular curved lines in the position of admedian lines in T. theobromae n. sp.; median line present and connected by transversal lines to admedian lines in T. eldoradensis ); and in the 6-rayed empodium (4–5 in T. eldoradensis ).

The internal female genitalia of the new species presents some similarities with that of T. tuttlei : the anterior and oblique apodemes present a similar shape and orientation, as well as the relative length of the longitudinal bridge and spermathecal shape. However in T. theobromae n. sp. the spermathecae are smaller than in T. tuttlei and the spermathecal duct is directed posteriad (directed laterad in T. tuttlei ). The female internal genitalia of the new species also presents some similarities with that of T. eldoradensis (e.g. spermatheca is spherical; spermathecal tube and vesicle are directed postero-laterad). However some remarkable differences are observed: the anterior apodeme is relatively wider in T. theobromae n. sp. (in T. theobromae n. sp. it is longer than the longitudinal bridge; in T. eldoradensis it is shorter than the longitudinal bridge); in T. theobromae n. sp. the oblique apodeme presents laterally curved extremities (in T. eldoradensis this is directed posteriad); in T. theobromae n. sp. the spermathecal tubes are tube-like (funnel-like in T. eldoradensis ); and in T. theobromae n. sp. the spermathecal vesicles are smaller than in T. eldoradensis .

Figures

FIGURE 3. Tetra theobromae n. sp. D. Dorsal habitus. V. Ventral habitus. PS. Prodorsal shield, female.

FIGURE 4. Tetra theobromae n. sp. L. Lateral habitus, female; GM. External genitalia, male; GF. External genitalia, female; IGF. Internal genitalia, female; E. Dorsal view of empodium, female (enlarged); L 1. Leg I, antaxial view, female; L 2. Leg II, antaxial view, female.