Calomyscus hotsoni, Thomas, 1920

Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Calomyscidae, Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona: Lynx Edicions, pp. 144-155 : 153

2.

Hotson’s Brush-tailed Mouse

Calomyscus hotsoni

French: Calomysque de Hotson / German: Hotson-Maushamster / Spanish: Raton de cola de cepillo de Hotson

Other common names: Hotson's Calomyscus, Hotson's Mouse-like Hamster, Hotson’s Mouse-tailed Hamster

Taxonomy. Calomyscus hotsoni Thomas, 1920 ,

“ Gwambuk Kaul , about 30 miles [= 48 Km] 8. W. of Panjgur;, 2,700 [= 823 m],” Makran District, W Balochistan, SW Pakistan .

Calomyscus hotsoni was originally recognized as a distinct species based primarily on its smaller size. It has been treated as a subspecies of C. bailwardi in several revisions in part based on undocumented report of intergradation with C. baluchi in southern Pakistan, a species that is morphologically very similar to C. bailwardi . Comprehensive revision of the genus in 1979 supported morphological distinctiveness of C. hotsoni , and it was returned to specific status. R. W. Norris and colleagues in 2008 demonstrated that C. hotsoni was morphologically and molecularly distinct from C. baluchi . Morphometric analyses with wider taxon sampling all support morphological distinctiveness of C. hotsoni . Phylogenetic analyses recover C. hotsoni as either the sister taxon of C. baluchi or C. bailwardi and consistently place these three taxa in a southern clade. Phylogeographic analyses recover clinal variation in size and molecular sequences among populations in south-eastern Iran. Three karyotypes have been reported from specimens in south-eastern Iran including a 2n = 48 and FNa = 46 from the Bagheran Mountains of South Khorasan Province, a 2n = 48 and FNa = 48 from the Birk and Malek Siah Kuh Mountains, and a 2n = 50 and FNa = 48 from the Birk Mountains of Sistan and Baluchestan Province. This demonstrates geographical variation among populations inhabiting these mountain ranges and polymorphism within the population in the Birk Mountains. While some of the specimens from the Bashagard Mountains (Hormozgan Province), the highlands in northern Fanuj (Sistan and Baluchestan Province), and Anbar Abad (Kerman Province) of south-eastern Iran reported as C. hotsoni by A. Khajeh and colleagues in 2015 likely represent this species, two of these localities are closer to known populations of C. bailwardi and so they may be representatives of that species. Monotypic.

Distribution. E & SE Iran, from Bagheran Mts of S Khorasan Province and desert mountain ranges (Abkhan, Malek Siah Kuh, and Birk) of Sistan and Baluchestan Province, E to dry coastal hills, the Central Makran Range and intermountain desert ranges of Balochistan in SW Pakistan, and Southern Kirthar Mts in Sindh Province of S Pakistan; it may occur in the Bashagard Mts, highlands in N Fanuj, and Anbar Abad of SE Iran.

Descriptive notes. Head-body 67-85 mm, tail 73-90 mm, ear 12-20 mm, hindfoot 16-20 mm; weight 14-25 g. Hotson’s Brush-tailed Mouse is one of the smaller species of brush-tailed mice, with ear generally being shorter than hindfoot. Skull has narrow interorbital region, palatal foramina of medium length, and rather small auditory bulla. Greatest length of skull ranges from 22-7 mm to 25-7 mm, with zygomatic breadths of 10-7-12-2 mm. M, has long entoconid cusp. Dorsal pelage is darker than in most other species of brush-tailed mice due to blackish tipped hairs.

Habitat. Rocky associated with dwarf palms ( Nannorrhops ritchieana, Arecaceae ) and dry, rocky mountaintops with shrubby vegetation at elevations of 67-1890 m in southern Pakistan and rocky hillsides and along rocky outcrops in association with vegetation including common fig ( Ficus carica, Moraceae ), pistachio ( Pistacia atlantica, Anacardiaceae ), ephedra ( Ephedra sp. , Ephedraceae ), and oats ( Avena sativa, Poaceae ) in south-eastern Iran. Hotson’s Brush-tailed Mouse appears to be restricted to the Saharo-Sindian phylogeographic region, an area characterized by hot, dry summers and mild winters.

Food and Feeding. In south-eastern Iran, Hotson’s Brush-tailed Mice appear to feed on seeds of common fig and pistachio because large amounts of seeds from these plants have been recovered from their burrows.

Breeding. Poorly known. A lactating female Hotson’s Brush-tailed Mouse was captured in June, and juveniles have been collected in May.

Activity patterns. No information.

Movements, Home range and Social organization. Based on trap success, Hotson’s Brush-tailed Mouse has considerable variation in densities, with 0-6% trap success at dry sparsely vegetated areas and 4-8% trap success at more mesic sites with more vegetation. It has a more calm behavior when handled than some other species of brushtailed mice. In captivity, it is highly social and does not show any aggressive behavior toward conspecific or congeneric cage mates. It occurs sympatrically with Persian Jird (Meriones persicus) and has been found inhabiting the same burrows in south-eastern Iran. Use of burrows of Persian Jirds may allow Hotson’s Brush-tailed Mouse to inhabit areas without sufficient rock crevices and voids for their nestsites.

Status and Conservation. Currently classified as Least Concern on The IUCN Red Lust. In 1996, it was classified as Endangered. Downlisting resulted from the known distribution of Hotson’s Brush-tailed Mouse being expanded from onlyits type locality in Balochistan to multiple areas in south-eastern Iran and south-western Pakistan. Prior to downlisting, recommendations had been made to establish a captive breeding population. Populations are known to occur in Kirthar and Hingol national parks in southern Pakistan. Recent surveys in south-eastern Iran have provided a better understanding of the habitat requirements of Hotson’s Brush-tailed Mouse.

Bibliography. Akbarirad et al. (2016b, 2016c), Corbet (1978), Ellerman (1941), Ellerman & Morrison-Scott (1951), Hamidi et al. (2017), Khajeh et al. (2015), Mohammadi et al. (2013), Molur et al. (2005), Norris, Morshed et al. (2003), Norris, Woods & Kilpatrick (2008), de Roguin (1988), Shahabi, Aliabadian et al. (2013), Shahabi, Zarei & Sahebjam (2010), Vorontsov et al. (1979), Zarei et al. (2013).

Figures

1. Zagros Mountains Brush-tailed Mouse (Calomyscus bailwardi), 2. Hotson’s Brush-tailed Mouse (Calomyscus hotsoni), 3. Pakistan Brush-tailed Mouse (Calomyscus baluchi), 4. Great Balkhan Brush-tailed Mouse (Calomyscus mystax), 5. Goodwin's Brush-tailed Mouse (Calomyscus elburzensis), 6. Noble Brush-tailed Mouse (Calomyscus grands), 7. Urar Brush-tailed Mouse (Calomyscus urartensis), 8. Syrian Brush-tailed Mouse (Calomyscus tsolovi)

Distribution. E & SE Iran, from Bagheran Mts of S Khorasan Province and desert mountain ranges (Abkhan, Malek Siah Kuh, and Birk) of Sistan and Baluchestan Province, E to dry coastal hills, the Central Makran Range and intermountain desert ranges of Balochistan in SW Pakistan, and Southern Kirthar Mts in Sindh Province of S Pakistan; it may occur in the Bashagard Mts, highlands in N Fanuj, and Anbar Abad of SE Iran.