379.

Fringed Myotis

Myotis thysanodes

French: Murin a queue frangée / German: Nordamerika-Fransenfledermaus / Spanish: Ratonero de flecos

Taxonomy. Myotis thysanodes G. S. Miller, 1897,

USA, “Old Fort Tejon [Tehachapi Mountains, Kern County], California,” USA.

Subgenus Pyzonix; lucifugus species group. See M. evotis . Four subspecies recognized.

Subspecies and Distribution. M.t.thysanodesG.S.Miller,1897—SWCanada(SBritishColumbia),WUSA(EWashington,EOregon,Idaho,WMon-tana,California,Nevada,Utah,SWyo-ming,Colorado,Arizona,NewMexico,andonerecordinNTexas),andN&CMexico.

M. t. aztecus G. S. Miller & G. M. Allen, 1928 — S Mexico.

M.t.pahasapensisJ.K.Jones&Genoways,1967—CUSA(EWyoming,SWSouthDa-kota,andNWNebraska).

M. t. vespertinus Manning & J. K. Jones, 1988 — W USA (SW Washington, W Oregon, and NW California).

Descriptive notes. Head-body 45-57 mm, tail 35-45 mm, hindfoot 9-12 mm, ear 16-20 mm, forearm 40-45 mm; weight 6-12 g. Dorsal pelage of the Fringed Myotis is generally yellowish brown to dark olivaceous (hairs with black bases); venteris nearly the same but slightly lighter. Individuals are darkest in north-west, sometimes being reddish brown to dark brown. Ears are long and extend beyond muzzle when laid forward. Calcar is unkeeled, and short pale fringe of hairs occurs along edge of uropatagium from tip of calcarto tail. Skull is large, with well-developed sagittal crest, but it is more slender and delicate than in the Cave Myotis ( M. velifer). M' and M? lack metaloph, protoconule, and often paraloph. Chromosomal complement has 2n = 44 and FN = 50.

Habitat. Various habitats including deserts, grasslands, and woodlands but most commonly oak, pinion, andjuniper woodlands or ponderosa pine ( Pinus ponderosa, Pinaceae) forests from sea level up to elevations of ¢. 2850 m (primarily 1200-2150 m).

Food and Feeding. Fringed Myotis feed primarily on Coleoptera but also other insects. They are slow and highly maneuverable fliers that forage near dense canopies.

Breeding. Copulation occurs in autumn in New Mexico after maternity colonies dispers. Females store sperm through winter until late April to mid-May when ovulation and fertilization occur. Gestation lasts ¢.50-60 days; births occur from late June to earlyJuly in New Mexico. They likely ovulate and give birth later in northern regions. Pregnant females have been captured in mid- to late June in Colorado and lactating females in early to mid-July in California. Shortly after birth, young open their eyes and ears, and skin pigmentation begins after about one week, followed by hair growth. Young started to fly after c¢.16-5 days and were indistinguishable from adults by 20-5 days old.

Activity patterns. Fringed Myotis use caves, mines, buildings, and occasionally bridges and rock crevices as day roosts. They leave roosts later in the evening than most other bats, being most active during the first 1-2 hours after sunset, but they can be captured until ¢.4-5 hours after sunset. They hibernate through winter (periodically arousing) from September until April. Calls are steep FM sweeps, with an average start frequency of 49 kHz, end frequency of 31 kHz, peak frequency of 34 kHz, and maximum duration of 8 milliseconds in Arizona.

Movements, Home range and Social organization. The Fringed Myotis roosts in colonies of 30-300 individuals. They often switch roosts; maternity colonies will switch roosts due to a temperature change in a roost. They migrate, but its exact magnitude is uncertain. They appear to move from higher to lower elevations in autumn.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Although the Fringed Myotis is widespread, it does not appear to be exceptionally common and generally is a small proportion of the bats captured in surveys. There do not appear to be any major threats, but roost disturbance and habitat destruction likely affectit locally. Southern Mexican populations might be more threatened because ¢.40% of habitat in the distribution of subspecies aztecus has been lost.

Bibliography. Arroyo-Cabrales & de Grammont (2017b), Bickham (1979b), Fenton & Bell (1981), Findley (1972), Hayes (2011), Hayes & Adams (2014), Jones & Genoways (1967b), Lacki & Baker (2007), Manning & Jones (1988), Miner etal. (1996), Morales & Carstens (2018), Morales et al. (2017), Musser & Durrani (1960), O'Farrell & Studier (1970, 1973, 1975, 1976, 1980), O'Farrell et al. (1971), Orr (1956), Platt et al. (2018), Rasheed et al. (1995), Studier & O'Farrell (1972, 1976), Studier, Lysengen & O'Farrell (1973), Studier, Procter & Howell (1970), Weller & Zabel (2001).