Tenuisternum

Fiaboe, K. K. M., De Moraes, G. J. & Gondim, M. G. C., 2004, A new genus and a new species of phytoseiid mite (Acari: Phytoseiidae) from northeastern Brazil, Zootaxa 599, pp. 1-4 : 1-2

Tenuisternum n. g.

TYPE SPECIES. Tenuisternum bahiense n. g., n. sp.

DIAGNOSIS. Females of this new genus are distinguishable by the following combination of characteristics: dorsal idiosomal shield distinctly wider anteriorly than posteriorly, areolate to polygonal pattern of the dorsal idiosomal shield, reduced sclerotization of ventral idiosomal shields (such that only the lateral margins of the sternal shield are faintly visible and metasternal shields are indistinct), genital shield considerably wider than ventrianal shield, absence of leg macrosetae and tubular spermathecal calyx. This new genus resembles Typhlodromalus Muma by the light sclerotization of the ventral idiosomal shields, the vase­shaped ventrianal shield and the tubular spermathecal calyx; it differs from that genus mostly, by the absence of leg macrosetae, in which it resembles genera in the tribe Neoseiulini, defined by Chant and McMurtry (2003). It differs from the latter group mostly by the light sclerotization of the ventral idiosomal shields, the vaseshaped ventrianal shield and the shape of the spermathecal calyx. It further differs from both groups by having dorsal idiosomal shield distinctly wider anteriorly than posteriorly and genital shield considerably wider than ventrianal shield.

ADULT FEMALE — ( Figs. 1–5 ). Dorsal idiosomal shield distinctly wider anteriorly than posteriorly, with areolate to polygonal pattern on most of its extent. With 19 pairs of dorsal idiosomal setae (pattern 10A:9B/JV­3:ZV of Chant & Yoshida­Shaul, 1992): 7 pairs of setae in the j­J series (j1, j3, j4, j5, j6, J2 and J5), 6 pairs of setae in the z­Z series (z2, z4, z5, Z1, Z4 and Z5), 4 pairs of setae in the s­S series (s4, S2, S4 and S5) and 2 pairs of setae in r–R series (r3 and R1). Dorsal shield setae subequal. With 5 pairs of sternal setae (st1–st5), 7 pairs of caudoventral setae (JV1, JV2, JV4, JV5, ZV1, ZV2 and ZV3), one of which on ventrianal shield (JV2), paranal and postanal setae. Sternal shield with only lateral margins faintly visible; metasternal shields indistinct. Genital shield considerably wider than ventrianal shield. With one pair of metapodal shields. Fixed cheliceral digit with 10 teeth; movable digit with 3 teeth. Leg macrosetae absent.

ADULT MALE — (Figa. 6–7). Dorsal shield pattern and chaetotaxy similar to female. Sternogenital shield lightly sclerotized. Caudoventral setae JV1, JV2, JV4, ZV1, ZV2 and ZV3 on ventrianal shield. Fixed cheliceral digit with 6 teeth; movable digit with 1 tooth. Leg macrosetae absent.

ETYMOLOGY. The generic name Tenuisternum is derived from the Latin tenuis, thin, rarefied, plus the Greek sternon, breast plate. It refers to the reduced sclerotization of idiosomal ventral shields. Neuter gender.

Figures

FIGURES 1 – 7. Tenuisternum bahiense n. g., n. sp.: Female — 1. Dorsal shield; 2. ventral surface; 3. Chelicera; 4. Spermatheca; 5. Leg IV. Male — 6. Ventrianal shield; 7. Spermatodactyl.