Meet the Northern Long-eared bat, Myotis septentrionalis (pronounced "my-oh-tis sep-ten-tree-oh-nal-is"). You may be forgiven for not recognizing the particular name, as it's also been known as the Northern bat ('septentrionalis' means "of the north"), and was previously assigned a different taxonomy (formerly a Mytois keenii subspecies). Rest assured, regardless of the nomenclature confusion, there is no mistaking this amazing bat with those distinctive long ears!
The Northern Long-eared bat shares many features with other species of other North American Myotis: these are fairly small bats with a body mass between 5-8 g, a body length of about 50 mm. The Northern's wingspan of about 200 mm is among the largest for a bat its size, and it has been suggested that the larger wing area coupled with a relatively longer tail are adaptations enabling foraging for insects occupying interior forest areas (whereas other North American Myotis bats generally forage in more open areas). And don't forget about the ears - it's likely that the extra surface area comes in handy when feeding in dense forests while stationed on a tree (known as "gleaning"). This foraging strategy is a distinctive behavior of these bats, though it can also can capture it's prey in flight (known as "aerial foraging") like other Myotis species. It's a stealthy eater too: the Northern Long-eared is able to emit an ultrasonic call to identify moth prey items that are nearly undetectable by the moth itself.
Despite a broad historic range spanning the boreal forests across Canada through eastern and north central United States, the Northern Long-eared bat is currently listed as a federally Threatened species under the Endangered Species Act [1]. Massive population declines are due primarily to a fungal pathogen causing White-nose Syndrome, a disease that has impacted many North American bats. In a grim twist of fate, these bats were previously so ubiquitous that there was little investment in understanding their natural history, thus detailed historical records regarding their ecology and behavior is limited. They have always been a tricky species to locate because they are much more solitary bats than other North American species.
In warm months these bats prefer snags tree hollows rather than more visible human structures like bridges and attics that other species like the Little Brown bat (Myotis lucifugus) or Big Brown bat (Eptesicus fuscus) are often detected. They spend the winter hibernating in caves like other North American bats, but prefer to hide in smaller crevices of instead of gathering in larger congregations. They might prefer the longest of winter naps, spending some of the longest hibernation periods of any Myotis, but they are frequently on the move in the summer with mothers moving their pup throughout the forest every 2-14 days.
Today, we share the chromosome-length genome assembly for the species. Contigging for this assembly was performed by Devon O'Rourke, Matt MacManes and Jeff Foster. Oxford Nanopore R9 flowcells were used to generate the initial raw data (5818511 total reads; 29116606101 total bases ; 8882 read length N50) from a single female adult specimen collected from West Tisbury, MA. These data were then basecalled with Albacore, reads trimmed with Porechop, and assembled into contigs with Flye (17,268 contigs, 1,998,235,525 bp, N50 217932). Illumina 150 bp PE reads were used to polish the scaffolds using three rounds of Racon and one round of Pilon. A second bat, a juvenile male, from Oak Bluffs, MA, was used for Hi-C data generation. This is the sixth chromosome-length bat genome assembly at the DNA Zoo, and the most contiguous genome assembly for common bats currently available!
Both bat specimen used for generating this assembly were collected thanks to Luanne Johnson, Director/Wildlife Biologist at BiodiversityWorks, who coordinated with the residents of the Martha's Vineyard island to make this project possible.
Despite over 1200 bat species throughout the world, only a few dozen genomes are currently available. We hope this contribution will enhance conservation management efforts that had previously relied on an alternative species (Myotis lucifugus) for population genetic investigations.
P.S.: We hear you fellow chiropterologists - bats don't have fangs, but the title was too fun!
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