Neosilphitrombium gratum Fain, 1992

Saboori, Alireza, Hajiqanbar, Hamidreza & Hakimitabar, Masoud, 2011, First Iranian species of Neosilphitrombium (Acari: Prostigmata: Neothrombiidae) with a key to world species, Zootaxa 2738, pp. 60-68 : 68

Neosilphitrombium gratum Fain, 1992

Fain (1992) described N. gratum but his description does not fit to standard criteria (e.g. number of normal setae on leg segments is neither mentioned in the text nor shown in figures). For this reason, we borrowed four paratypes of N. gratum and present some supplementary data.

Diagnosis. Larvae with the following features (n = 4): fn Ge = 4-2-2; fnTi = 6-5-5; fnTa = 18-13-13; fζ = 2-0- 0; fε = 1-1-0; microseta present on Ti I; SD = 75–94; leg I 223 238; leg II 192–200; leg III 217–227; IP = 635–665. Number of dorsal setae of idiosoma (fD) varies in four paratype specimens as follows: 30, 32, 37, 36 and number of ventral setae of idiosoma (fV) as follows: 24, 24, 37, 25. Palpal setal formula (fPp) = 0-0-0- BNN 2-BBBNNω. There are nude adoral setae on gnathosoma. Leg setal formula: Leg I: Ta- 1ω, 1ε, 2ζ, 17n; Ti- 2φ, 1κ, 6n; Ge- 2σ, 1κ, 4n; Fe- 6n; Tr- 1n; Cx- 3n (+1 eI). Leg II: Ta-1ω, 1ε, 13n; Ti- 2 φ, 5n; Ge- 1σ, 2n; Fe- 4n; Tr-1n; Cx- 4n. Leg III: Ta- 13n; Ti- 5n; Ge- 1σ, 2n; Fe- 4n; Tr- 1n; Cx- 2n.

Measurements are given in Table 2.

Remarks. Our study on N. tenebrionidum and N. gratum showed that the number of normal setae on the dorsal and ventral idiosoma varies, whereas the number of normal setae on legs is typically constant and has no variation. In N. annabellae only Ti II has 4–5 normal setae (Haitlinger, personal communication) which we considered 4 normal setae as an abnormality because there are 5 normal setae on Ti II in Trombidioidea (including Neothrombiidae ) except Achaemenothrombiidae (see Saboori et al. 2010). The presence of the supracoxal seta on coxa I (in N. tenebrionidum and N. gratum ) is the first report of this seta in the Neothrombiidae (see Saboori et al. 2010).