Metaculus rapistri Carmona 1969

Monfreda, Rosita & Lillo, Enrico De, 2012, Eriophyoid mites (Acari: Eriophyoidea) on Brassicaceae: a new species of Metaculus from Turkey and remarks on other species associated with brassicaceous plants, Zootaxa 3154, pp. 47-60 : 50-53

Metaculus rapistri Carmona 1969

( Fig. 3 )

Description. FEMALE. Body spindle shaped, 158 (140‒190, n = 11), 54 (52‒62) thick, 46 (41‒58) wide. Gnathosoma 23 (18‒24), projecting obliquely downwards, chelicerae 16 (12‒16), pedipalp seta d 6 (5‒6). Prodorsal shield 37 (30‒37) plus 7 (7‒9) for a sub-triangular and slightly pointed anterior lobe over cheliceral base, 47 (43‒48) wide; shield pattern almost obscure, composed of two, thin, admedian lines extending down posterior 3/4 of shield, and two curved submedian lines anteriorly connecting with admedian lines. Tubercles sc on rear shield margin, 27 (25‒29) apart, setae sc 26 (21‒26) directed to rear. Leg I 37 (26‒38), tibia 9 (8‒10), tarsus 7 (6‒8), ω 8 (7‒8) distally rounded, empodium simple, 4, 4-rayed; seta bv 12 (11‒13), seta l ʹʹ26 (23‒28), seta l ʹ 5 (4‒6), seta ft ʹ 23 (21‒24), seta ft ʹʹ 18 (16‒22). Leg II 35 (28‒37), tibia 8 (7‒9), tarsus 6 (6‒7), ω 7 (6‒7) distally rounded, empodium simple, 4, 4-rayed; seta bv 11 (10‒13), seta l ʹʹ 9 (7‒10), seta ft ʹ 5 (4‒6), seta ft ʹʹ 21 (19‒23). Coxae with fine granules on most surfaces; setae and tubercles 1b absent, setae 1a 15 (10‒18), tubercles 1a 9 (7‒10) apart, setae 2a 38 (23‒42), tubercles 2a 23 (19‒23) apart. Prosternal apodeme 7 (6‒8). Opisthosoma with 35 (30‒38) broad, dorsal semiannuli with faint microtubercles, 61 (57‒65) narrow and microtuberculate ventral semiannuli. Rounded microtubercles located on rear margin of ventral semiannuli. Elongated microtubercles ventrally on rear 8 (7‒9) ventral annuli. Setae c2 30 (25‒33), on ventral semiannulus 9 (8‒10), setae d 48 (45‒60), on ventral semiannulus 24 (21‒26); setae e 10 (8‒17), on annulus 38 (36‒41); setae f 22 (18‒32), on ventral semiannulus 56 (52‒60). Setae h2 43 (43‒55); setae h1 4 (3‒4), strong. Genitalia 16 (13‒17), 23 (21‒24) wide, with 10 longitudinal striae; setae 3a 14 (10‒15), 15 (14‒18) apart.

MALE. Body spindle shaped, 143 (n = 1). Prodorsal shield 34 plus 6 for the subtriangular and slightly pointed anterior lobe over cheliceral base. Tubercles sc on rear shield margin, 26 apart, setae sc 19 directed to rear. Opisthosoma with 34 broad, dorsal semiannuli with faint microtubercles, 58 narrow and microtuberculate ventral semiannuli.

Host plant in Turkey. Isatis tinctoria L. ( Brassicaceae ), Dyer’s woad.

Relation to the host. In April (mid spring), leaves of rosettes, particularly the youngest, were strongly deformed appearing to be rolled on their longitudinal axis and quite twisted; leaves were also a bit darker in colour ( Fig. 4 ).

Localities. Goreme, Turkey, 38°38'24 N, 34°51'10 E, 1201 m elev., 11 March 2007 (BBCA sample code #TK 091107), collected by Cristofaro M. and Di Cristina F.; Goreme, Turkey, 38°38'233 N; 34°51'097 E, 1207 m elev., 1 April 2007 (CABI sample code #TRIS8), collected by Hinz H.L. and Gerber E. The male was not found in the sample indexed as #TK 091107 but one male was mounted from the #TRIS8 sample. Samples #TK 091107 and #TRIS8 consist of dried stems and leaves.

Differential diagnosis and remarks. The measured Turkish population appears to be slightly smaller than that described from Portugal. Other morphometric differences could be pointed out on the basis of the data available from Carmona (1969).

Two other phyllocoptine mites have been found on brassicaceous hosts: Aculops arabis Keifer 1972 and Aculops lepidii ( Roivainen 1953) . Metaculus differs from Aculops / Aculus by lacking setae 1b on the leg coxisternal area. Even though A. lepidii was assigned to Aculus ( Amrine & Stasny 1994) , there was no information on the setae of the first pair of leg coxae either from the morphometric data or lateral drawing made by Roivainen (1953). Also, other literature on this species ( Farkas 1965; Davis et al. 1982; Amrine & Stasny 1994) did not add any further data and nothing is known about the availability of Roivainen’s original collection. On the basis of the available literature, anterior lobe shape, distance between sc tubercles, length of the sc setae and the ratio between these measurements, appear to be the main differences between the Spanish specimens of A. lepidii (Roivainen’s description) and Turkish specimens of Metaculus (current description). These characters may not be sufficient to consistently separate these two species and specimens from Spain are needed for making a valuable comparison and clarifying the correct taxonomical position of the Spanish population. Additionally, the Metaculus populations found in Turkey and Portugal and that of A. lepidii from Spain, are all associated with brassicaceous plants. All were found to cause leaf deformation of their host plants.

Figures

FIGURE 3. Metaculus rapistri Carmona (schematic drawings). Scale bar: 10 µm for AP, CS, DA, GF, L; 5 µm for ES, L 1; 2 µm for E.

FIGURE 4. Isatis tinctoria L.: leaf deformations (courtesy of Dr Cristofaro M., ENEA, Casaccia, Roma).