Ragusaseius Kreiter, 2010

Kreiter, S. & Tixier, M. - S., 2010, A New Genus And Species Of Phytoseiid Mites (Acari: Mesostigmata) From The Brazilian Atlantic Forest, Acarologia 50 (2), pp. 197-205 : 198-199

Ragusaseius Kreiter , genus novum

Type species Ragusaseius ferraguti n. sp.

Diagnosis — This genus belongs to the sub-family Amblyseiinae as setae z3 and s6 are absent. It is unique in the combination of the following characteristics: dorsal setae serrated, all medium to long except for J5, presence of both J3 and J4 on the dorsal shield in addition to j1, j3, j4, j5, j6, J2, J5, ventrianal shield anteriorly eroded, with only JV2 and occasionally ZV 2 in addition to circumanal setae. Having the peritremal shield fused anteriorly with adult dorsal shield ( Fig. 1A ), more than 25 pairs of idiosomal setae present, a sternal shield without posterior projection, a deutosternal groove narrow <5 µm in width, without forward migration of preanal setae JV2 and ZV2, preanal setae on male usually arranged in a triangular pattern, setae S4 present, ratio seta s4:Z1 <3.0:1.0, setae s4, Z4 and Z5 not greatly longer than other setae, setae J2 present, Ge II and Ge III without macroseta, fixed digit of the chelicera with more than 6 teeth, Ragusaseius n. gen. keys to the tribe Neoseiulini ( Chant and McMurtry, 2007) . Chant and Mc Murtry (2007) defined this tribe as follows: ratio seta s4:j6 <3.0:1.0; chelicera of normal size and shape, with fixed digit usually having 5 or fewer teeth; posterior margin of sternal shield straight or concave; peritremal shield narrow; preanal setae of female arranged in a triangular pattern; dorsolateral setae approximately equal in length. Within the tribe Neoseiulini , Ragusaseius n. gen. resembles the genera Macrocaudus Moraes, McMurtry and Mineiro , Evansoseius Sheals , Rubuseius Ragusa and Chileseius Gonzalez and Schuster in having more than 5 teeth on cheliceral digit and setae J4 present. However, it differs from Chileseius because of the absence of setae j6 and ZV3 and presence of setae J3, from Evansoseius because of the absence of setae r5 and J1 and the presence of setae R1 and J3, and at last from Rubuseius because of the presence of setae J3 and absence of setae J1. The genus Macrocaudus is the most similar to Ragusaseius n. gen. because of the presence of both J3 and J4. However JV3 is absent in Ragusaseius n. gen. whereas present in Macrocaudus . In conclusion, Ragusaseius differs from all these species in the following combination of characters: pre-anal setae not arranged triangular because ventrianal shield is reduced, setae J3 and J4 present and setae JV3 absent.

Because of all these singular characters, Ragusaseius ferraguti n. gen. is erected as a new genus in the tribe Neoseiulini

Adult Female ( Figures 1-2 ) — Dorsal idiosomal shield reticulated, more regularly in the anterior part (propodosoma) than in the posterior part (opisthosoma). With 21 pairs of serrated and medium to long dorsal setae which can be assigned to the following formula: 10A: 11C/JV-3: ZV; this formula is unique within the Phytoseiidae (Chant and Yoshida-Shaul, 1992; Chant and McMurtry, 2007): 9 pairs of setae in the j-J series (j1, j3, j4, j5, j6, J2, J3, J4, J5), 6 pairs of setae in the z-Z series (z2, z4, z5, Z1, Z4, Z5), 4 pairs of setae in the s-S series (s4, S2, S4, S5), and 2 pairs of setae in the r-R series (r3, R1). The dorsal shield bears 4 pairs of solenostomes (gd1, gd2, gd6, gd9) and 16 pairs of poroids. Lines j3-gd1-z2 and z4-gd2-z4 with angles> than 180. Lines Z1-gd6-z5 and R1-gd6-j6 forming each almost an angle of 180°. Solenostome gd9 very close to S5. Apex of peritremes extending to the level between j1 and j3. Sternal shield smooth. Anterior and posterior margins of the sternal shield convex and slightly concave, respectively. Five pairs of sternal setae (st1-st5; setae st4 on metasternal shield). Ventrianal shield vase-shaped, reticulated and anteriorly eroded, 7 pairs of caudoventral setae (JV1, JV2, JV4, JV5, ZV1, ZV2, ZV3); JV2 and occasionally ZV2 are the only pairs of setae inserted on the ventrianal shield (in addition to circumanal setae); setae JV3 absent; with one pair of solenostome, gv3. With two pairs of metapodal shields. Spermatheca with calyx pocular; atrium not distinct. Fixed cheliceral digit multidentate; movable digit with several large

Acarologia 50(2): 197–205 (2010)

teeth. No distinct macrosetae on the first 3 pairs of legs; leg IV with 3 slightly knobbed macrosetae.

Adult Male ( Figure 3 ) — Reticulation of idiosomal shields and chaetotaxy similar to female. Anterior and posterior margins of sternogenital shield convex and straight, respectively. Seta JV5 on caudoventral cuticule; other caudoventral setae (JV1, JV2 and ZV2) on the sub-triangular ventrianal shield. Spermatodactyl L-shaped.

Etymology — The name of the genus refers to Professor Salvatore Ragusa di Chiara (University of Palermo, Italy), who has greatly contributed to the taxonomy and biology of the phytoseiids.

Figures

FIGURE 1: Ragusaseius ferraguti n. g., n. sp.. Female. (A) – Dorsal idiosoma; (B) – Ventral idiosoma; (C) – Variation in shape of the ventrianal shield.

FIGURE 2: Ragusaseius ferraguti n. g., n. sp.. Female. (A) – Variation in shape of the ventrianal shield. The most common are a, b (female paratypes) and c (female holotype and several paratypes). Setae JV2 usually present. Only one specimen (g) with one member of setae ZV2 in addition to JV2; (B) – Leg IV; (C) – Chelicera; (D) – Spermatheca.

FIGURE 3: Ragusaseius ferraguti n. g., n. sp.. Male; (A) – Dorsal idiosoma; (B) – Ventral idiosoma; (C) – Spermatodactyl.