Holotype: 1♂ (GUSAL), Turkey: Şırnak Province, İdil District, Yörük Village (37°16'47.54"N, 42°1'17.18"E), 655 m, 12 May 2007, leg. E.A. Yağmur and H. Koç.

Paratypes. 2 ♂, 4♀ (GUSAL), 1 ♂, 1♀ (AZMM=Alaşehir Zoological Museum, Manisa) same data as holotype.

Up to now only known from type locality in the Şırnak Province, Turkey.

The new species is similar to Z. anatolicus (Kulczyński 1903: 660; Šilhavý 1956: 34, figs 1–5; -1965: 382–384, figs 1–13, Staręga 1976: 376, figs 75–77; Chevrizov 1979: 22, figs 119–121) and Z. redikorzevi (Staręga and Chevrizov 1978: 419–422, figs 1–2; Staręga 1978: 219; Chevrizov 1979: 22, figs 122–124; Kurt et al. 2011: 146–147, figs 1–8). The differences between these species are given in Table 1.

The specific epithet is in honor of Dr. Osman SEYYAR (Niğde University, Niğde, Turkey), who has made important contributions to Turkish arachnology.

Male: body length 7.2 mm, width 4.5 mm; chelicera basal segment 2.8 mm, second segment 3.7 mm.

Body (Fig. 1a): approximately oval-shaped in dorsal view. Opening of odoriferous gland prominent with 1–2 black denticles. Cephalothorax covered with small black denticles. Carapace ochre-brown. Abdomen dorsally with distinct brownish-gray saddle. Saddle with longitudinal whitish-yellow stripe in the center. Abdominal tergites with transverse rows of dark brown spots, not denticulated.

Tuber oculorum (Fig. 4f): nearly hemispherical, median furrow present, relatively low and with 1–2 setae on each side.

Ventral side (Fig. 1c): coxae and genital operculum covered with sparse hairs. Abdomen ventrally with transverse rows of brown spots, and with sparse hairs.

Chelicerae (Fig. 2, 4e): strong, robust and dark ochre brown. Basal segment apically not widened and slightly bent, dorsally with small black-tipped tubercles and setae, ventrally with long black-tipped tubercles. Second segment apically widened, zebra-like stripe pattern of pigmentation, and covered with setae.

Pedipalp (Fig. 3): normally structured, strong; ochre-brown and with dark brown spots. Coxae with finger-shaped apophysis and covered with long setae; trochanter relatively long, ventrally and dorsally with black tubercles and setae; femur of male slighty curved, dorsally and ventrally covered with black-tipped tubercles and setae; patella distally with usual bulge densely hairy in female, less developed in male: similar in tibia; tibia and tarsus only with setae, but male tarsus ventrally bearing black microdenticles, tarsal claw smooth.

Legs (Fig. 4a–d): short and strong, light ochre-brown and with dark brown spots. Femur to tarsus I relatively thicker than in legs II to IV. Femur and patella I with setae, tibia ventrally with microdenticles and dorsally with setae, metatarsus ventrally covered with densely spaced microdenticles, tarsus bearing only setae. Leg pairs II and III with sparse setae. Femur and tibia IV ventrally covered with black denticles, and dorsally setae; metatarsus IV ventrally with bristle, dorsally with microdenticles; tarsus ventrally bristle, dorsally with setae.

Male genital morphology (Fig. 1d–f): truncus wide at base, proximal fourth of shaft straight-sided; then slightly narrowed at the center; straight-sided from center to distal end of shaft, forming a spoon-shape, wings not very wide; glans stocky, widened, not elongated, not banana-shaped; stylus long.

Female: body length 9.0 mm, width 4.7 mm; chelicera basal segment 1.5 mm, second segment 2.1 mm. General appearance similar to that of male, but body larger and wider (Fig. 1b). Second segment of chelicerae normally structured, not enlarged, basal segment ventrally without tubercles.

This paper describes a new species belonging to the genus Zachaeus. This genus has five species (Z. anatolicus, Z. crista, Z. hebraicus, Z. orchimonti, and Z. redikorzevi) in Turkey. Z. anatolicus is distributed in Bulgaria, Caucasus, Crimea, Greece, former Yugoslavia, and Turkey (Adana, Ankara, Bayburt, Gümüşhane, Kayseri and Manisa Provinces) and Z. redikorzevi is recorded from Russia and Turkey (Bayburt, Gümüşhane, and Osmaniye Provinces) (Kurt 2014). Z. crista is distributed throughout South and Eastern Europe, Caucasus. It is widespread in Turkey (Ankara, Antalya, Bayburt, Bilecik, Bolu, Denizli, Gümüşhane, İzmir, Kırıkkale, Niğde and Osmaniye Provinces). Z. hebraicus is known from Jordan, Israel, Lebanon, Libya, Syria and Turkey (Adana, Manisa Provinces). Z. orchimonti is only known from Turkey (Aydın, Denizli, İzmir and Manisa Provinces) (Giltay, 1932) and Z. kervillei is known from Syria (Roewer 1923). The new species differs from Z. hebraicus, Z. crista, and Z. kervillei by the presence of setae only on the ocularium, abdomen not denticulated dorsally, and legs I–III femora covered with setae only (Z. hebraicus, Z. crista, and Z. kervillei are characterized by ocularium with denticles, abdomen dorsally denticulated, and leg I–III femora covered with denticles). Zachaeus seyyari sp. nov. differs from Z. orchimonti by a setose ocularium, femur of pedipalp dorsally and ventrally covered with black-tipped tubercles and setae (in Z. orchimonti, ocularium with 5–7 small denticles and femur of pedipalp with setae).

With Zachaeus seyyari sp. n., the number of Zachaeus species known from Turkey is now increased to 6. Considering the geographical features of Turkeyand the habitat preferences of the genus, the number of species will surely increase with ongoing studies in the future.