New sucker-footed bat fossils have been recently located in a desert in northern Egypt, the location of which has taken researchers by surprise. Today, however, Madagascar sucker-footed bats are restricted to the small island, only. In light of recent findings, this was clearly not always the case, and researchers now conjecture that the unusual bat species evolved in Africa, before moving on to thrive in South America.
The fossilized remains of two extinct bat species, which are the distant relatives of the Madagascar sucker-footed bats, were very recently unearthed by a team of experts. The researchers used multiple sets of fossilized jawbones and teeth from the newly discovered bat species – found within the Sahara Desert – to demonstrate the sucker-footed bat to be at least 36 million years older than previously estimated. The latest findings were published in the Feb. 4 issue of the journal PLOS ONE, and represent the first time that the family has been formally described in the fossil record.
Co-author Nancy Simmons, who is curator of the American Museum of Natural History’s Mammalogy Department, recently explained researchers had previously theorized that the sucker-footed bats were related to an ancient lineage, principally based upon evidence collected from DNA sequencing experiments. Simmons claims the bats had been previously placed “… close to very old groups in the bat family tree,” but there was an absence of fossil records to corroborate these suspicions.
The modern sucker-footed bats consist of two distinct species, endemic to Madagascar, including Myzopoda aurita and M. schliemanni. M. aurita mainly inhabits palm forests along the east coast of Madagascar, including the forest on the Masoala Peninsula. Adults of the species are close to 60 millimeters in length, with large ears and dense, golden-brown colored fur.
M. schliemanni, meanwhile, tend to populate lowland areas in the central regions of the island. The bats have been known to roost in caves and feed on a diet of Blattaria and Lepidoptera. Both species of bats, as suggested by their nomenclature, bear sessile pads on their ankles and wrists, facilitating their attachment to leaf surfaces. Unlike most other bat species, the sucker-footed bats do not hang upside-down to cave ceilings or branches, but, instead, employ their cup-like pads to roost head-up. The pads rely upon wet adhesion, similar to tree frogs, to ensure they maintain an upright position.
The newly identified fossils were from two extinct species, Phasmatonycteris phiomensis and P. butleri, and are estimated to date back to between 30 and 37 million years ago, respectively; they flittered through the skies during a time when the landscape was dramatically different. According to Gregg Gunnell, the director of the Duke University Lemur Center’s Division of Fossil Primates, parts of Northern Africa were tropical, densely populated with forests and home to a myriad of different mammals:
“The habitat was probably fairly forested, and there was likely a proto-Nile River, a big river that led into the ancient Tethys Ocean.”
Simmons also explains that the arid conditions of the Fayum Depression of Egypt’s Western Desert, where the team conducted their fieldwork, boasts conditions that are ideal for preserving fossilized deposits. After investigating sets of fossilized teeth, they concluded that the bats fed on insects, just like their modern-day relatives. Of course, it is not possible for the team to truly understand whether these creatures, at the time, possessed the characteristic sucker-feet that today’s sucker-footed bats possess; however, their mere existence supports the contention that they are the most primitive members of a lineage that predominates South America.
Based upon the new findings, Gunnell believes that the superfamily, which most bats belong to (Noctilionidae), had its roots in Africa, just before moving eastward as Gondwana was splitting apart – where Gondwana consisted of the two southerly supercontinents, in existence around 500 to 180 million years ago. After migrating to Australia, the bats then detoured through Antarctica and then headed into South America.
By James Fenner