Feltria (Feltria) aculeata, Tuzovskij, Petr V. & Semenchenko, Ksenia A., 2009

Tuzovskij, Petr V. & Semenchenko, Ksenia A., 2009, New water mites species of the genus Feltria Koenike (Acariformes, Feltriidae) from the Asian Russia, Zootaxa 2124, pp. 38-50 : 39-41

Feltria (Feltria) aculeata sp. n.

( Figs. 1–8 )

Type series. Holotype: male (29-kas– IBSS), Russia, Khabarovsk Territory, Komsomolsky District, Komsomolsk–on–Amur – Nikolaevsk–on–Amur road, near road bridge, the Amur River basin, the Axyan River, N 50°46.266’; E 138°05.471’; depth 60 cm; substrates: stones, pebbles. 0 1.07.2005, coll. K.A. Semenchenko, D.A. Sidorov.

Description. Male. Body flat and oval. Dorsal shield very large, covering almost all dorsal surface, supplied with five pairs of setae: Oi, Oe, Sci, Li, Si ( Fig. 1 ). Setae Fp, Hi, Oi, Oe, Sci, Li, Si without glandularia, other dorsal idiosomal setae located on smooth interscutal membrane around the dorsal shield. Setae Fch, Vi, Ve, He, Sce and Le provided by glandularia and located on small separate platelets. Setae Fp and Hi situated on very small sclerites. Anterior and posterior margins of dorsal shield convex, with lateral margins more or less parallel to each other. All lyriform organs placed on dorsum: i1 on platelets, bearing setae Vi, i2 between setae Ve and Hi, i3 behind setae He, i4 behind setae Sce, and i5 behind setae Le.

Leg coxae incorporated into four groups, situated closely but not fused to each other, and occupied about two thirds of venter surface ( Fig. 2 ). Second coxae not extending to midline, posterior apodemes of first coxae short and posterolaterally directed. Medial pair of setae (Pe) located between fourth coxae and genital plate, lacking glandularia and situated on posterior extensions of fourth coxae; lateral pair of setae (Se) with glandularia and situated on posterior extensions of fourth coxae too. Genital plate large and separate from posterior extensions of fourth coxae; acetabula 18 on one side and 19 on the other side of genital plate. Ventrolateral platelets free and extending between fourth coxae and genital plate. Gonoporus located near anterior end of genital plate. Pregenital sclerite very small, located between posteromedial corners of fourth coxae. Excretory pore, setae Pi and setae Ci with glandularia situated free on smooth interscutal membrane behind genital plate.

Pedipalp slender ( Fig. 3 ). Trochanter relatively short, with single dorsodistal seta. Femur with three thick proximal and two thin dorsodistal setae, ventrally with proximoventrally directed projection, bearing rather numerous sharp-pointed spines ( Fig. 4 ). Genu with two thin dorsodistal setae. Tibia very long and narrow with two unequal ventral setae and one short distolateral spine. Surface of femur and genu with cell-shaped reticulation, surface of tibia with strips.

First four segments of all legs provided with thick setae ( Fig. 5 ). Tarsus of leg III straight and slightly expanded in a median portion, with small flat ventrolateral ledge, bearing 6–8 short modified setae with flat or rounded tips and one relatively long thin seta ( Fig. 6–7 ).

Claws ( Fig. 8 ) with three dents: large median, short and thin internal and external ones. Ventral margin of claw plate concave.

Measurements (n=1). Length of body 455, width 318; length of dorsal shield 378, width 252; length of seta Fch 30; length of genital plate 155, width 270; length of pedipalpal segments (P 1–5): 36, 66, 63, 123, 27; length of coxae I–IV 312; length of leg segments: I — 45, 60, 60, 78, 102, 96; II — 45, 63, 54, 72, 102, 90; III — 50, 48, 60, 78, 110, 102; IV — 78, 75, 72, 93, 120, 96.

Differential diagnosis. The new species is similar to the European species Feltria denticulata Angelier, 1949 and to the North American subspecies F. echinopalpis echinopalpis Cook, 1963 and F. echinopalpis projecta Cook, 1970 . All coxal groups in F. echinopalpis echinopalpis are fused without trace of a suture line, the tarsus of leg III is expanded with six pointed modified setae ( Cook 1963); in contrast, in F. aculeata sp. n. all coxal groups are separated, the tarsus of leg III is slightly expanded with 6–8 blunt setae. In F. echinopalpis projecta the excretory pore plate and the setae Ci with associated glandularia are fused with the genital plate, the tarsus of leg III is expanded and curved with five partially fused short setae ( Cook 1970); in F. aculeata sp. n. the excretory pore platelets and the setae Ci with associated glandularia are not fused with the genital plate, the tarsus of leg III straight and slightly expanded with 6–8 separated short setae. F. aculeata sp. n. differs from F. denticulata in the following characters (character states of F. denticulata are indicated in parentheses from Gledhill 1983): the anterior coxal groups are separated (fused to each other), the medial pair of setae (Pe) between the fourth coxae and the genital field without glandularia (with glandularia), the lateral pair of setae (Se) with glandularia is fused with the posterior extension of the coxae IV (lying free on smooth membrane between the fourth coxae and the genital field), the excretory pore and the setae Ci with glandularia are lying free (fused with the genital field), the tarsus of leg III is slightly expanded with 6–8 blunt spines (well expanded with 4–5 pointed spines).

It should be noted that the new subspecies has more common features with the North American subspecies F. echinopalpis echinopalpis and F. echinopalpis projecta , than with the European species F. denticulata . However, it can be distinguished from all these species by the following features: the tarsus of leg III slightly expanded; the excretory pore and associated setae (Pi and Ci) with glandularia are situated free on smooth interscutal membrane behind the genital plate.

Etymology. Named for its proximoventrally directed projection on the femur of pedipalp, bearing sharppointed spines (from lat. “ aculeáta ” – spiny).

Habitat. Running waters.

Distribution. Khabarovsk Territory, Far East of Russia.

Figures

FIGURES 1 – 2. Feltria aculeata sp. n., male: 1, idiosoma, dorsal view; 2, idiosoma, ventral view. Scale bar = 100 μm.

FIGURES 3 – 8. Feltria aculeata sp. n., male: 3, pedipalp, medial view; 4, proximoventral projection of pedipalp femur; 5, leg I; 6, distal portions of genu, tibia and tarsus of leg III; 7, modified ventrolateral setae of tarsus III; 8, claw of leg I. Scale bars = 50 μm for Figs. 3, 5 – 7; 25 μm for Figs. 4, 8.