470.

Stalker’s Myotis

Myotis stalkeri

French: Murin de Stalker / German: Stalker-LangfulRfledermaus / Spanish: Ratonero de Stalker

Other common names: Kei Myotis, Moluccan Mouse-eared Bat

Taxonomy. Myotis (Leuconoe) stalker: Thomas, 1910,

“Ara, Kei |= Kai] Islands,” Moluccas, Indonesia.

Subgenus Myotis; horsfieldi: species group. Myotis stalker: has been considered sister to and even conspecific with M. macrotarsus . It has also been grouped with M. macrotarsus and M. vivest in a macrotarsus-group. Taxonomic studies are required to clarify it status. Monotypic.

Distribution. Raja Ampat Is (Gebe, Waigeo, and Batanta), and Kai Is (Kai Kecil).

Descriptive notes. Head-body 49-73 mm, tail 49-6-55- 5 mm, ear 18-20- 1 mm, hindfoot 15-16 mm, forearm 48-6-51- 3 mm; weight 16-18 g. Stalker’s Myotis is large, with extraordinarily large feet. Its color is similar to a small version of the Ghost Falsevampire (Macroderma gigas). In flight, overall impression of Stalker’s Myotisis that of a large, gracefulsilvery blue bat, with pale wings and pale belly. Upperparts are generally variable grayish brown, with silvery gloss; hairs are blackish, with dark brown tips. Head is somewhat grayer. Underparts strongly contrast upperparts, being creamy whitish with salty hairs for two-third their lengths. Limbs and membranes are uniform pale brown and entirely naked, except at base of tail. Uropatagium is not fringed as in the Pallid Large-footed Myotis ( M. macrotarsus) and the Eurasian Pond Myotis ( M. dasycneme). Ears are medium-sized. Tragus is long, narrow, and pointed, with well-marked external basal lobe. Feet are exceedingly large, with sharp laterally compressed claws. Philippine and Bornean Pallid Large-footed Myotis seems to be more brownish and smaller in some measurements (e.g. tragus length). Skull is generally large (greatest length of skull 19- 3 mm, type specimen). P’? is one-half the size of P* and intruded, and adjacent premolars almost in contact. P, small but in tooth row. Condylo-basal lengths are 17-6-18- 2 mm (three males from Waigeo), zygomatic breadths are 11-7- 12- 1 mm (three males from Waigeo), and maxillary tooth row length is 9- 1 mm (one male from Waigeo).

Habitat. Limestone caves with tall forest in immediate vicinity and surrounding countryside dominated by heathland and low open forest on ultrabasic soil (Gebe) and surrounded by rainforest and water surfaces between small islets (Waigeo), only recorded below 250 m.

Food and Feeding. Stalker’s Myotisis considered to be water and cave dependent, possibly feeding on fish as suggested byits very large feet, powerful claws, and unfringed uropatagium.

Breeding. On Gebe in November, one of two female Stalker’s Myotis carried a naked young, weighing 7 g. Six other individuals examined were subadults weighing 12-16 g that might have been born in the previous year. This suggests seasonal breeding, with births occurring in November—December. If this is correct, individuals do not reach sexual maturity until after the first year. Males caught on Waigeo had active testes in the beginning ofJuly.

Activity patterns. Stalker’s Myotis are nocturnal.

Movements, Home range and Social organization. A small colony of Stalker’s Myotis on Kai in 1993 shared the roost with Fawn-colored Leaf-nosed Bats (Hipposideros cervinus), Small Asian Sheath-tailed Bats (Emballonura alecto), Little Long-fingered Bats ( Miniopterus australis), Indonesian Tomb Bats (7aphozous achates), and New Guinea Broadeared Horseshoe Bats (Rhinolophus euryotis). Roosting colonies of up to 100 Stalker’s Myotis have been observed. On Gebe, a colony of ¢.100 individuals roosted in the apices of solution holes and inner chambers, sharing the cave with species of Miniopterus, Biak Leaf-nosed Bats (H. papua), and Raffray’s Sheath-tailed Bats E. raffrayana). On Waigeo, they were found in only one (Lopintol IT) of four caves surveyed and occurred on inner chamber of the cave, where it was hot and sticky and where some Miniopterus and New Guinea Broad-eared Horseshoe Bats raised their young. In this cave, Stalker’s Myotis was also associated with Beaufort’s Naked-backed Fruit Bats ( Dobsonia beaufortz), Temminck’s Trident Bats (Aselliscus tricuspidatus), Hipposideros ct. maggietaylorae, New Guinea Broad-eared Horseshoe Bats, Maluku Myotis ( Myotis moluccarum), and three species of Miniopterus .

Status and Conservation. Classified as Data Deficient on The IUCN Red List. Stalker’s Myotis might be declining, but there is a shortage of survey and ecological data to validate this. Disturbance at cave roosts might be a threat, and protection of known roosting sites and important foraging areas is needed.

Bibliography. Corbet & Hill (1992), Findley (1972), Flannery (1995a), Helgen (2007a), Hutson, Kingston & Francis (2008e), Koopman (1994), Meinig (2002, 2013), Simmons (2005), Tate (1941d), Thomas (1910b), Wiantoro (2011).