390.

Velvety Myotis

Myotis simus

French: Murin camus / German: Samtiges Mausohr / Spanish: Ratonero aterciopelado

Taxonomy. Myotis simus Thomas, 1901,

“Sarayacu, Peru.” Expanded from holotype information by R. K. LaVal in 1973b to “Sarayacu, Rio Ucayali, Loreto, Peru, elevation ca. 100 m.”

Subgenus Pyzonix; ruber species group. Taxonomic status of populations associated with the Parana River basin needs to be reviewed, considering description of M. midastactus . Monotypic.

Distribution. Endemic to South America, with records in Colombia, Ecuador, Peru, N & CW Brazil, and NE Argentina (Parana River basin). Occurrence localities in Bolivia and Paraguay were attributed to recently described M. midastactus .

Descriptive notes. Head-body ¢. 50-52 mm, tail 31-37 mm, ear 11-13 mm, hindfoot 7-9 mm, forearm 35-5-39- 7 mm; weight 5-11 g. The Velvety Myotis is the most distinctive Neotropical species of Myotis . It differs from all other South American myotine bats—except the Golden Myotis ( M. midastactus)—by having its plagiopatagium attached at toes by narrow band of membrane or attached at ankle. Pelage is woolly and less than 5 mm long. Ventral hairs are generally slightly bicolored (2:8-4- 2 mm long); dorsal hairs are unicolored, without contrast between bases and tips (3-1-5- 3 mm). Color and length offur vary seasonally. Specimens from Ecuador collected in February—March had short and unicolored orange-brown fur, whereas specimens collected in October and December had longer and chocolate-brown fur, with slightly burnished tips. No geographical pattern in color variation has been detected. Ears are short, extending forward halfway from eye to nostril. Antitragal notch is barely evident; tragus is pointed, slightly curving outward above and convex below, with small triangular lobule at outer base. Ears and membranes are blackish. Fringe of hairs along trailing edge of uropatagium is absent. Few scattered hairs are present on basal part of uropatagium. Calcar usually has small keel. Baculum is long and narrow, with slightly projecting lateral knobs. Skull is moderately long (greatest skull lengths 13-6-14- 8 mm), with broad and well-marked interorbital constriction dorsally and short rostrum. Laterally, parietal is generally inclined forward, and supraoccipital region is flattened. Sagittal crest is generally present, occipital crests are always present, and sagittal and occipital crests range from very low to high. Compared with other New World myotine bats, the Velvety Myotis has larger C! in length and basal section and shorter distance between C! and P*, implying lingual displacement of P? and especially P°. In several specimens, P° is displaced lingually in a way that P? seems to be in contact with P*. Distal border of P* has conspicuous indentation, forming striking inner lobe. Chromosomal complement has 2n = 44 and FN = 50, with three large and one small metacentric and 17 medium to small acrocentric pairs of autosomes. X-chromosome is medium submetacentric, and Y-chromosome is small acrocentric.

Habitat. Different well-preserved formations, including terra firma and floodplain areas in lowland forest and savanna, at elevations of 28-600 m.

Food and Feeding. The Velvety Myotis is insectivorous and forages in forested areas and over water.

Breeding. One volant young female Velvety Myotis was caught in April in Argentina. Other young specimens were caught in January, October, and December in Brazil; February-March in Ecuador; and April in Peru. Pregnant females were caught in October in Paraguay and February-March in Peru,all of them with single embryos. One male from Balta, Peru, had spermatozoa production with all stages of spermatogenesis in tubules and swollen epididymides packed with spermatozoa. These data suggest a non-seasonal polyestry.

Activity patterns. The Velvety Myotis emergesjust before sunset. Individuals mostly use lower forest strata and roost in banana leaves, hollow trees, holes in the ground, and thatched roofs of houses.

Movements, Home range and Social organization. The Velvety Myotis forms colonies of up to 50 individuals. It roosts with other bat species such as Lesser Bulldog Bats ( Noctilio albiventris) and Argentine Serotines ( Eptesicus furinalis).

Status and Conservation. Classified as Data Deficient on The IUCN Red Lust.

Bibliography. Ascorra et al. (1996), Baker & Jordan (1970), Barquez & Diaz (2016h), Barquez et al. (1999), Koopman (1994), LaVal (1973b), Lépez-Gonzélez (2004), Lopez-Gonzalez et al. (2001), Moratelli (2012), Moratelli & Morielle-Versute (2007), Moratelli & Wilson (2014a), Moratelli, Idarraga & Wilson (2015), Moratelli, Peracchi & Oliveira (2011), Munoz-Arango (2001), Myers & Wetzel (1983), Simmons (2005), Thomas (1901a), Wilson (2008Db).