| Free-tailed bats Temporal range: LateEocene to recent | |
|---|---|
 | |
| Unidentified molossid: Note that the tail extends beyond the uropatagium | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Chiroptera |
| Superfamily: | Vespertilionoidea |
| Family: | Molossidae Gervais inde Castelnau, 1855 |
| Type genus | |
| Molossus Geoffroy, 1805 | |
| Subfamilies | |
TheMolossidae, orfree-tailed bats, are a family ofbats within the order Chiroptera.[1]The Molossidae is the fourth-largest family of bats, containing about 110 species as of 2012.[2] They are generally quite robust, and consist of many strong-flying forms with relatively long and narrow wings with wrinkled lips shared through their genus.[3] Their strong flying form allows them to fly 60 miles per hour using tail winds and at altitudes over 10,000 feet.[3] This makes them unique among bats, as they are the only bat family that withstands the elevation. They are widespread, being found on every continent except Antarctica. They are typically found in caves, abandoned mines, or tunnels.[3]
The family's scientific name comes from thetype genusMolossus, which in turn is from theMolossus breed of dogs.[4]
The family's common name is derived from a length of "free" tail, projecting beyond the end of theuropatagium—the membrane that connects the base of the tail to the hind legs.[citation needed]
Another common name for some members of this group, and indeed a few species from other families, ismastiff bat. Thewestern mastiff bat (Eumops perotis), a large species from thesouthwestern United States andMexico with wings over 0.5 m (1.6 ft) across, is perhaps one of the best known with this name. They are widespread, being found on every continent except Antarctica.[citation needed]
The tail is usually best seen when resting. A special ring ofcartilage slides up or down the tailvertebrae by muscular action to stretch or retract the tail membrane. This gives many species a degree of fine tuning in their flight maneuvers to rival their day-flying ecological equivalents, such asswifts,swallows, andmartins. As a result, these animals include the fastest-flying of all bat species among their number.[5] Thedental formula of free-tailed bats varies between species:1.1.1-2.2-31-3.1.2.3
Free-tailed bats are usually grey, brown, or black in color, with some exceptions. They range from 4 to 12 cm (1.6 to 4.7 in) in length, excluding the tail, and can weigh from 8 to 220 g (0.28 to 7.76 oz), depending on species. They areinsectivorous, and catch their food on the wing. While some species roost in small groups in hollow trees or rocky crevices, some cave-dwelling species form vast colonies of up to 50 million individuals.[5]
Molecular sequence data support themonophyly of the Molossidae as a whole, but not that of many of its genera, such asChaerephon,Mops,Mormopterus, andTadarida. The grouping ofChaerephon minusC. jobimena plusMops was found to be monophyletic, as wasOtomops.[6]
| Internal relationship of Molossinae[2] |
A 2012 study attempted to show the relationships of genera within the subfamily Molossinae (the other subfamily of Molossidae, Tomopeatinae, only contains theblunt-eared bat).[2]This study usedgenetic data to create aphylogeny, which contrasted from previous phylogenies constructed usingmorphological data.Traits that were previously used to group species, such as having a flat skull, were shown to have no relation to evolutionary relationship, meaning that flat-headedness evolved multiple times within the family.Of the 16 genera of Molossinae, 15 were used to create the phylogeny (left), with researchers unable to includePeters's flat-headed bat, the only member ofPlatymops.
The results of this study showed thatChaerephon isparaphyletic, forming aclade withMops.There was strong support forOld World andNew World clades.While the genusTadarida has one New World species, theMexican free-tailed bat, the genus itself has its origins in the Old World.The most recent common ancestor ofTadarida with New World genera was 29 million years ago.Severaltribes have been proposed within the Molossinae.Ammermanet al. proposed Molossini (containingMolossus,Eumops,Molossops,Cynomops,Neoplatymops,Nyctinomops, andPromops); Tadarini (containingTadarida,Chaerephon,Mops,Platymops,Sauromys,Myopterus, andOtomops); Cheiromelini (containingCheiromeles); and Mormopterini (containingMormopterus)[2]
The 18 genera contain about 100 species:
FAMILY MOLOSSIDAE
The name of the [free-tailed bats] family is derived from the Greekmolossus, a kind of dog used by Greek shepherds in ancient times
