Myotis keenii (Merriam, 1895)

Don E. Wilson & Russell A. Mittermeier, 2019, Vespertilionidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 716-981 : 928

377.

Keen’s Myotis

Myotis keenii

French: Murin de Keen / German: Keen-Mausohr / Spanish: Ratonero de Keen

Taxonomy. Vespertilio subulatus keenii Merriam, 1895 ,

“Massett, Queen Charlotte Islands [= Haida Gwaii], British]. C[olumbia].,” Canada.

Subgenus Pyzonix; lucifugus species group. See M. evotis . Genetic analyses suggest that M. keenii and M. evotis represent a single species with a morphometric cline that partially explains variation, but this issue remains unresolved. Monotypic.

Distribution. Restricted in coastal Pacific Northwest, from extreme SE Alaska S along British Columbia, including Haida Gwaii and Vancouver I ( Canada), to NW Washington ( USA).

Descriptive notes. Head—-body 40-55 mm, tail 34-44 mm, ear 16-20 mm, hindfoot 8-10 mm, forearm 34- 6-39 mm; weight 4-6 g. Keen’s Myotis is morphologically distinct from its North American congeners, except the Long-eared Myotis ( M. evotis ) and the Northern Myotis (M. septentrionalis ). Fur is long and silky. Dorsal hairs are bicolored, with blackish bases and golden brown, reddish, or olive-brown tips. Ventral hairs are strongly bicolored, with dark brown bases and pale yellowish tips. Ears are long, extending noticeably beyond tip of nose when laid forward; tragusis long, narrow, and pointed. Membranes and ears are blackish. Plagiopatagium is attached to feet by a broad band of membrane; uropatagium has minute intermittent hairs at its edge. Calcar has indistinct keel. Skull is large (greatest skull lengths 14-6-15- 6 mm) and slender with steep forehead; sagittal and lambdoidal crests generally are present; and length of upper tooth row slightly exceeds greatest palatal breadth including molar.

Habitat. Large coastal old growth forests but occasionally anthropogenic habitats. Maternity roosts and summer feeding areas in British Columbia are at elevations below 240 m, and hibernation sites occur above 400 m.

Food and Feeding. Keen's Myotis is forages in forests and near water. It has been observed catching insects in flight over hot spring pools and clearings above scrubby salal ( Gaultheria shallon, Ericaceae ). It prefers spiders ( Araneae ) and moths ( Lepidoptera ), but other flying insects such as midges, flies and mosquitoes ( Diptera ), and caddisflies (Trichoptera) are also eaten.

Breeding. Keen's Myotis mates in autumn or early winter before entering hibernation; females store sperm until spring. Upon leaving hibernacula, pregnant females move to maternity roosts in early summer (April-May) where they stay until young are born. Gestation lasts ¢.40-60 days. Females have one offspring per year. Maternity roosts are known only from a hydrothermally heated system of rock crevices and a lodgepole pine ( Pinus contorta, Pinaceae ) snag.

Activity patterns. Keen’s Myotis can be active at dusk and dawn. It hibernates during winter and becomes torpid during daytime roosting. It roosts under bark of large trees and in hollow trees, caves, rock crevices, and man-made structures (e.g. bridges and house attics).

Movements, Home range and Social organization. Keen’s Myotis make small-scale movements between summer roosts and suitable hibernacula, but they do not make long-distance migrations. They tend to stay relatively close to roosting sites, and estimated daily movements are less than 1 km. They will return to specific foraging areas annually. Maternity roosts have 30-40 females, and hibernacula were reported as the residence for large colonies of individuals, even sharing with other species of bat.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Keen's Myotis is widespread, presumably has a large population, occurs in some protected areas, and is unlikely to be declining at a rate to qualify for listing in a threatened category.

Bibliography. Fitch & Shump (1979), Lausen et al. (2019), Nagorsen & Brigham (1993), Parker et al. (1997), Simmons (2005), Wilson & Ruff (1999), van Zyll de Jong (1985).

Figures

366. Disk-footed Bat (Eudiscopus denticulus), 367. Taiwan Broad-muzzled Bat (Submyotodon latirostris), 368. HimalayanBroad-muzzled Bat (Submyotodon caliginosus), 369. Moupin Broad-muzzled Bat (Submyotodon moupinensis), 370. Northern Myotis (Myotis septentrionalis), 371. South-western Myotis (Myotis auriculus), 372. Western Small-footed Myotis (Myotis ciliolabrum), 373. Dark-nosed Small-footed Myotis (Myotis melanorhinus), 374. Eastern Small-footed Myotis (Myotis leibii), 375. California Myotis (Myotis californicus), 376. Little Brown Myotis (Myotis lucifugus), 377. Keen’s Myotis (Myotis keenii), 378. Long-eared Myotis (Myotis evotis), 379. Fringed Myotis (Myotis thysanodes), 380. Arizona Myotis (Myotis occultus), 381. Long-legged Myotis (Myotis volans), 382. Flat-headed Myotis (Myotis planiceps), 383. Indiana Myotis (Myotis sodalis), 384. Cinnamon Myotis (Myotis fortidens), 385. Findley’s Myotis (Myotis findleyi), 386. Northern Hairy-legged Myotis (Myotis pilosatibialis), 387. Southern Hairy-legged Myotis (Myotis keaysi), 388. Red Myotis (Myotis ruber), 389. Riparian Myotis (Myotis riparius), 390. Velvety Myotis (Myotis simus), 391. Golden Myous (Myotis midastactus), 392. Elegant Myotis (Myotis elegans), 393. Fish-eating Myotis (Myotis vivesi)

Distribution. Restricted in coastal Pacific Northwest, from extreme SE Alaska S along British Columbia, including Haida Gwaii and Vancouver I ( Canada ), to NW Washington ( USA ).