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Myotis septentrionalis (Trouessart 1897)

Order Chiroptera : Family Vespertilionidae

DESCRIPTION. This is a small bat with dull, gray-brown pelage. Compared with other Myotis from Texas, M. septentrionalis has relatively long ears and an unkeeled calcar. As with all Myotis, this bat also has a narrow and sharp-pointed tragus. Dental formula: I 2/3, C 1/1, Pm 3/3, M 3/3 × 2 = 38. Averages for external measurements: total length, 78 mm; tail, 26 mm; foot, 9 mm; ear, 13 mm; forearm, 35 mm. Weight, 6–9 g.

Myotis septentrionalis

DISTRIBUTION. Although M. septentrionalis is widely distributed over eastern and northern North America, it is known in Texas on the basis of a single specimen collected at Winter Haven, Dimmit County, in southern Texas. This specimen (comprising a skin and skull) was sent by S. E. Jones to the Division of Insects, US Bureau of Entomology, United States National Museum, on 19 August 1942.

Distribution of Myotis septentrionalis

SUBSPECIES. Monotypic species.

HABITS. This bat hibernates in caves and mine tunnels in eastern Canada and in the United States from Vermont to Nebraska southward to Louisiana and Mississippi. It is more solitary in its habits than other Myotis, generally found singly or in small groups of up to 100 individuals. In summer, this bat may occasionally be found in hollow trees, rock crevices, behind tree bark, and in buildings.

Myotis septentrionalis commonly forages along forest edges, over forest clearings, and occasionally over ponds, but specific food habits remain unknown. These bats typically take their prey from the ground, branches, or foliage rather than catching them in flight. They usually carry their catches to perches to feed.

Little is known of the reproductive habits of this bat. Small nursery colonies seem the rule, and twinning may occasionally occur.

POPULATION STATUS. Extralimital. The northern long-eared myotis is known in Texas on the basis of a single specimen collected in South Texas >70 years ago. Until recently, this was thought to represent a vagrant or wandering individual and, although it is still listed that way in this volume, the recent discovery of a population in western Louisiana, just across the border from Texas, raises the possibility of a permanent resident population in our state. Obviously, there is a need for more fieldwork in eastern Texas to determine the status of this species.

CONSERVATION STATUS. The IUCN status of the northern long-eared bat is least concern, and it does not appear on the federal or state list of concerned species. The IUCN listing is because of its wide distribution, presumably large (stable) population, occurrence in a number of protected areas, and the likelihood that it is not declining at a rate required for inclusion in a threatened category.

REMARKS. Although it was previously considered a subspecies of Myotis keenii (M. k. septentrionalis), van Zyll de Jong, a Canadian mammalogist, elevated M. septentrionalis to full species status based on cranial, dental, and external characters. This taxonomic rearrangement created two monotypic species, M. keenii of the northwestern United States and Canada and the paler M. septentrionalis of eastern North America.

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From The Mammals of Texas, Seventh Edition by David J. Schmidly and Robert D. Bradley, copyright © 1994, 2004, 2016.  Courtesy of the University of Texas Press.

Natural Science Research Laboratory