Dinychus serratus, Kontschán, Jenő & Starý, Josef, 2011

Kontschán, Jenő & Starý, Josef, 2011, Uropodina species from Vietnam (Acari: Mesostigmata), Zootaxa 2807, pp. 1-28 : 5-7

Dinychus serratus sp. nov.

( Figs 7–12)

Material examined. Holotype. Female ( HNHM), Vietnam, Lao Cai Prov., Sín Chai, Hoáng Liên N.P. Tram Ton, along and over a rivulet, 1936 m, 22 ° 20.941 ’N 103 ° 46.197 ’E, from fallen acorns with soil, 12 December 2008, L. Peregovits coll. Paratypes. Male ( HNHM), and female and male ( ISB), locality and date same as holotype.

Description. Female. Length of idiosoma 510–530 µm, width 280–290 µm (n= 2). Idiosoma oval.

Dorsal idiosoma ( Fig. 7). Marginal and dorsal shields not fused anteriorly. All setae on dorsal shield ca 27–45 µm long, needle-like, basally serrate. Setae on marginal shield similar in shape and length to those on dorsal shield. Surface of posterior platelets smooth, with two pairs of basally serrate, needle-like setae and one pair of smooth, needle-like setae ( Fig. 8). Surface of dorsal and marginal shields alveolar.

Ventral idiosoma ( Fig. 9). Sternal setae short (ca 6–9 µm), smooth, needle-like. St 1 placed at the level of central region of coxae II, St 2 at the level of posterior margin of coxae III, St 3 at the level of central region of coxae III, and St 4 situated at the level of central region of coxae IV, St 5 near posterior edges of genital shield. Sternal shield with reticulate sculptural pattern anterior to genital shield and oval pits between coxae III and IV. Ventral shield covered by alveolar pits, all ventral setae smooth, needle-like, ca 17–30 µm long. Adanal setae and postanal setae similar in length and shape to ventral setae. Peritremes long and m-shaped ( Fig. 10). Genital shield linguliform, placed between coxae III and IV, without anterior process and sculptural pattern. Tritosternum ( Fig. 11) with narrow base, tritosternal laciniae subdivided into four branches, the lateral branches smooth, central branches with bulbiform apices.

Gnathosoma ( Fig. 11). Corniculi horn-like, internal malae apically subdivided into two branches. Hypostomal setae h 1 long (ca 40–45 µm), basally serrate, h 2 and h 3 needle-like, h 2 ca 27–29 µm long, h 3 ca 20–22 µm long, h 4 short (ca 5–6 µm), marginally serrate. Chelicerae not clearly visible. Palp trochanter with two serrate ventral setae. Epistome with three marginally serrate branches.

Legs. Ornamented with small alveolar sculptural pattern, and with smooth and serrate setae, all legs with ambulacral claws.

Male. Length of idiosoma 530–540 µm, width 280–290 µm (n = 2). Shape of idiosoma, ornamentation, and dorsal chaetotaxy as in female. All sternal setae short (ca 7–9 µm) and needle-like; St 1 placed near central region of coxae II, St 2 near posterior margin of coxae II, St 3 placed near central region of coxae III, St 4 and St 5 near central region of genital shield. Surface of sternal shield near coxae covered by alveolar pits. Genital shield oval, placed between coxae III and IV ( Fig. 12). Ventral setae and ornamentation similar to those of female.

Etymology. The name of this species refers to its basally serrate dorsal setae.

Remarks. On the basis of the setae on posterior platelets (one pair of smooth and two pairs of serrate), this species belongs to the Dinychus perforatus group ( Hirschmann et al., 1984). The reticulate sculptural pattern on the sternal shield near the anterior margin of genital shield and the basally serrate dorsal setae are unique characters in the Dinychus perforatus group.