Eryx sistanensis Eskandarzadeh & Rastegar-Pouyani & Rastegar-Pouyani & Zargan & Hajinourmohamadi & Nazarov & Sami & Rajabizadeh & Nabizadeh & Navaian 2020, sp. nov.
Creators: name: Eskandarzadeh, Naeimeh
name: Rastegar-Pouyani, Nasrullah
name: Rastegar-Pouyani, Eskandar
name: Zargan, Jamil
name: Hajinourmohamadi, Ashkan
name: Nazarov, Roman A.
name: Sami, Soheil
name: Rajabizadeh, Mahdi
name: Nabizadeh, Hossein
name: Navaian, Majid
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Squamata
Boidae
Eryx
Eryx sistanensis

description: Eryx sistanensis sp. nov.   
(Figs. 2–6)  
 Holotype: HCHSU 6469, a juvenile female, collected from Jahan-abad, about 20 km east of Zabol in Sistan & Baluchistan Province, Iran.   
 Paratype: A male specimen (HCHSU 8487), from Sistan & Baluchistan Province, collected on the road from Jask to Chabahar near Bent (in a direct path about 600 km South of the type locality).   
 Etymology: Eryx sistanensis sp. nov. is named after the Sistan Region in Sistan & Baluchistan Province, where the holotype was collected.   
 Diagnosis: Eryx sistanensis sp. nov. and E. johnii differ from other erycids by having the banding pattern on the tail, although this pattern is not always observed in the specimens of E. johnii (Boulenger 1893; Wall 1912; Smith 1943; Minton 1966; Leviton & Anderson 1970; Sorensen 1988; Das 1991; Sharma 2007). As Russell (1801) stated in the description of the type specimen of E. johnii: “the obtuse point of the tail resembles the head, and in point of thickness sometimes exceeds it.” In our specimens of the new species, the end of the tail is not as blunt as E. johnii and the thickness of the end of the tail is less than that of the head (Fig. 2). Despite the overlapping ranges in the pholidosis and morphometric characters of E. sistanensis sp. nov. and E. johnii, E. sistanensis sp. nov. differs from E. johnii by having fewer dorsal scale rows at midbody (43–56 versus 47–67).   
 Description of holotype (Fig. 3): A juvenile, body length 220 mm, and tail length 30 mm. The ratio of interocular space width to distance between the posterior edge of the eye and the corner of the mouth 1.2. Head small, indistinct from the neck; eye small, on side of the head, bordered by 11 and 10 small scales on each side; six large scales between the eyes. Two elongated postinternasal scales; the first four rows of the scales immediately after the rostral arranged in a symmetric pattern. Three scales between the eye and nasal. Eleven supralabial scales; the second supralabial scale higher than the third. Dorsal surface of the body with small scales (DRS 43:43:38). Ventral scales 190, wider than dorsal scales. Subcaudal scales 26. The scales of the dorsal surface of tail slightly keeled.   
 Coloration of holotype: The preserved specimen in alcohol has paler color than that in alive specimen. Dorsal ground color of the preserved specimen in alcohol was yellow with shadows of grey color. The banding pattern was obvious on the tail with three large dark spots; a very pale shadow of patched areas was observed over the dorsal surface of the trunk. The ventral surface was yellow.   
 Description of paratype (Fig. 4): The head was almost destroyed and the pholidotic characters couldn’t be entirely studied. The detailed meristic and morphometric characters of the holotype and paratype are presented in Table 4.   
 Additional material: The morphological characters of the third specimen, an adult male (Fig. 5), from Gurband Village, Minab County in Hormozgan Province that was solely for morphological study is presented in Table 4. The symmetric pattern of the head scales was similar to the holotype specimen. As in the holotype specimen, the eyes were lateral surrounded by small scales; large scales between the eyes; the second supralabial scale was higher than the third and having two elongated postinternasal scales.   
 Variation in color: Pictures of two additional specimens from Rikukash in Sistan & Baluchistan Province (25.88N 61.68E) and near Shamil Village (27.5N 56.85E) in Hormozgan Province (Fig. 6) were also observed. These specimens had been photographed in farms by local people. In spite of the common banding pattern observed in all the studied and photographed specimens, they show different color patterns. HCHSU 8487 was grey in dorsal surface; the banding pattern along the body was more obvious than that in the holotype specimen. The head was black; ventral surface was cream with some black spots forming a narrow line in the middle of ventral surface; this line was discontinuous. The dorsal color of the specimens from Gurband was reddish brown; having large black patches on the dorsal surface; from tail to the head the patches were faint and irregular. Head with black shadow. The color pattern of the specimen from Shamil was similar to that from Gurband. The specimen from Rikukash has darker background color and the banding pattern is less obvious and less regular than the other specimens.   
 Distribution: Eryx sistanensis sp. nov. is currently known from Zabol in Sistan Region to the southern parts of Sistan & Baluchistan and Hormozgan Provinces (Fig. 7).   
 Habitat: The specimens were observed in agricultural fields with soft substrates (Fig. 8). The farms were surrounded by natural vegetation such as Tamarix, Zygophyllum, Acacia and Chenopodiaceae shrubs.   
 The morphological characters of the studied specimens of E. sistanensis sp. nov. and the two populations of E. johnii available from literature are presented in Table 5.   
 We herein provide an updated identification key (after Das 1991) for E. sistanensis sp. nov. and its Indian relatives:   
1a- Rostral without angular edge............................................................................ 2  
1b- Rostral with sharp angular edge.......................................................................... 3  
 2a- Tail tip pointed; keeled dorsal body scales in 40–55 rows; 161–196 ventral scales........................... E. conicus   
 2b- Tail tip rounded; smooth dorsal body scales in 50–54 rows; 201–206 ventral scales........................ E. whitakeri   
 3a- Tail extremely blunt; often as wide as head; with or without banding pattern on the body or tail................. E. johnii   
 3b- Tail not as blunt as in E. johnii, the thickness of tail tip less than head; the banding pattern is obvious on the tail and sometimes on the body......................................................................... E. sistanensis sp. nov.
description: Published as part of Eskandarzadeh, Naeimeh, Rastegar-Pouyani, Nasrullah, Rastegar-Pouyani, Eskandar, Zargan, Jamil, Hajinourmohamadi, Ashkan, Nazarov, Roman A., Sami, Soheil, Rajabizadeh, Mahdi, Nabizadeh, Hossein & Navaian, Majid, 2020, A new species of Eryx (Serpentes: Erycidae) from Iran, pp. 182-192 in Zootaxa 4767 (1) on pages 185-188, DOI: 10.11646/zootaxa.4767.1.8, http://zenodo.org/record/3770697