Spermophilus fulvus (Lichtenstein, 1823). Naturwissenschaftliche Abhandlungen, Eversmann's Reise: 119.

Type locality: “ near the Kuvandzhur River, east of Mugodzhary Mountains, north of Aral Sea” [Kazakhstan] (Ognev, 1963:29).

Habitat. Spermophilus fulvus inhabits dry steppe areas with sparse grass and also the edges of cultivated areas.

Distribution. This species was collected from 5 localities in Iran (Figure 1, Table 1).

External characters. The dorsum is reddish with a yellowish tone (Figure 2). There is no demarcation line between the flanks and venter. The venter is pale grey. The base of the tail is the same color as the dorsum.. This coloration gets darker towards the tip of the tail, with a dark ring near the white tip. The hairs of the tail are longer than those of the body. Fore- and hind feet are whitish dorsally and darker ventrally.

Cranial characters. The skull is robust and about 25% larger than that of the other three species (Figure 4). Lambdoidal and sagittal crests are pronounced in adult and old adult specimens. Postorbital processes are prominent and heavily built. The skull is not uniformly convex in the dorsal aspect and appears more angular in a lateral view. Unlike the other three species, the rostrum is not tapered anteriorly; in dorsal view, the rostrum widens at the anterior end of the premaxillas. The mandible is also larger than that of the other three species but it is similar in general shape. The anterior edges of the zygomatic arch form an approximate right angle at the junction with the rostrum in adult animals, but this angle is obtuse in young specimens. The anterior surface of the incisors is white in most specimens, 70% of upper incisors and 85 % of lower incisors. Posterior palatal foramina are mostly (95%) located posterior to a line passing between M2 and M3. There is a spine-like process in the medial posterior margin of the palate.

Dentition. The dental formula is the same as in S. citellus. Pm1 has 1 root. Pm2, M1, M2, and M3 have 3 roots. Pm1 has 2 roots; M1, M2, and M3 have 4 roots.

Karyology. The karyotype for specimens from Hamedan, Mashad and Zenjan (Iran) is 2n= 36, NF=70, and NFa= 66. All of the autosomal chromosomes are bi-armed. The X chromosome is large and submetacentric and the Y chromosome is the smallest of the acrocentric chromosomes.