Horseshoe bat

Taxonomic history Rhinolophus was first described as a genus in 1799 by French naturalist Bernard Germain de Lacépède. Initially, all extant horseshoe bats were in Rhinolophus, as well as the species now in Hipposideros (roundleaf bats). At first, Rhinolophus was within the family Vespertilionidae. In 1825, British zoologist John Edward Gray subdivided Vespertilionidae into subfamilies, including what he called Rhinolophina. English zoologist Thomas Bell is credited as the first to recognize horseshoe bats as a separate family, using Rhinolophidae in 1836. While Bell is sometimes recognized as the authority for Rhinolophidae, the authority is more often given as Gray, 1825. Horseshoe bats are in the superfamily Rhinolophoidea, along with Craseonycteridae, Hipposideridae Megadermatidae, Rhinonycteridae, and Rhinopomatidae. After the split into Rhinolophidae and Hipposideridae, further divisions were proposed for Rhinolophus, with Rhinolphyllotis in 1934 and Rhinomegalophus in 1951, though both additional genera were returned to Rhinolophus. Various subgenera have been proposed as well, with six listed by Csorba et al. in 2003: Aquias, Phyllorhina, Rhinolophus, Indorhinolophus, Coelophyllus, and Rhinophyllotis. The biogeography of horseshoe bats is poorly understood. Various studies have proposed that the family originated in Europe, Asia, or Africa. A 2010 study supported an Asian or Oriental origin of the family, with rapid evolutionary radiations of the African and Oriental clades during the Oligocene. }} Rhinolophidae is represented by one extant genus, Rhinolophus. Both the family and the genus are confirmed as monophyletic (containing all descendants of a common ancestor). As of 2019, there were 106 described species in Rhinolophus, making it the second-most speciose genus of bat after Myotis. Rhinolophus may be undersampled in the Afrotropical realm, with one genetic study estimating that there could be up to twelve cryptic species in the region. Additionally, some taxa recognized as full species have been found to have little genetic divergence. Rhinolophus kahuzi may be a synonym for the Ruwenzori horseshoe bat (R. ruwenzorii), and R. gorongosae or R. rhodesiae may be synonyms of the Bushveld horseshoe bat (R. simulator). Additionally, Smithers's horseshoe bat (R. smithersi), Cohen's horseshoe bat (R. cohenae), and the Mount Mabu horseshoe bat (R. mabuensis) all have little genetic divergence from Hildebrandt's horseshoe bat (R. hildebrandtii). Recognizing the former three as full species leaves Hildebrandt's horseshoe bat paraphyletic. The second genus in Rhinolophidae is the extinct Palaeonycteris, with the type species Palaeonycteris robustus. Palaeonycteris robustus lived during the Lower Miocene and its fossilized remains were found in Saint-Gérand-le-Puy, France. ==Description==

Appearance Horseshoe bats are considered small or medium microbats. The majority of species have long, soft fur, but the woolly and lesser woolly horseshoe bats (R. luctus and R. beddomei) are unusual in their very long, woolly fur. In a few horseshoe bat species, males have a false nipple in each armpit. The horseshoe is above the upper lip and is thin and flat. The lancet is triangular, pointed, and pocketed, and points up between the bats' eyes. The sella is a flat, ridge-like structure at the center of the nose. It rises from behind the nostrils and points out perpendicular from the head. This is atypical among bat families, as most newborns have at least some milk teeth at birth, which are quickly replaced by the permanent set. Postcrania Several bones in its thorax are fused—the presternum, first rib, partial second rib, seventh cervical vertebra, first thoracic vertebra—making a solid ring. Except for the first digit, which has two phalanges, all of their toes have three phalanges. This distinguishes them from hipposiderids, which have two phalanges in all toes. The tail is completely enclosed in the uropatagium (tail membrane), and the trailing edge of the uropatagium has calcars (cartilaginous spurs). ==Biology and ecology==

Echolocation and hearing helps focus echolocation; pictured is Rüppell's horseshoe bat (R. fumigatus)|alt=A horseshoe bat viewed in profile with its left wing closest to the camera. The sella is pronounced from this angle, sticking straight out of the center of the nose-leaf. The bat has grayish-brown fur, and the skin on its forearm is pinkish. Horseshoe bats have very small eyes and their field of vision is limited by their large nose-leafs; thus, vision is unlikely to be a very important sense. Instead, they use echolocation to navigate, They echolocate at particularly high frequencies for bats, though not as high as hipposiderids relative to their body sizes, and the majority concentrate most of the echolocation energy into the second harmonic. The king horseshoe bat (R. rex) and the large-eared horseshoe bat (R. philippensis) are examples of outlier species that concentrate energy into the first harmonic rather than the second. Their highly furrowed nose-leafs likely assist in focusing the emission of sound, reducing the effect of environmental clutter. The nose-leaf in general acts like a parabolic reflector, aiming the produced sound while simultaneously shielding the ear from some of it.|alt=Two bat silhouettes. The top, a horseshoe bat, has shorter, broad wings. The second, a free-tailed bat, has very long and narrow wings. Horseshoe bats are insectivorous, though consume other arthropods such as spiders, While a majority of horseshoe bats are nocturnal and hunt at night, Blyth's horseshoe bat (R. lepidus) is known to forage during the daytime on Tioman Island. This is hypothesized as a response to a lack of diurnal avian (day-active bird) predators on the island. They have especially small and rounded wingtips, low wing loading (meaning they have large wings relative to body mass), and high camber. These factors give them increased agility, and they are capable of making quick, tight turns at slow speeds. Some species, particularly temperate species, have an annual breeding season in the fall, while other species mate in the spring. Gestation takes approximately seven weeks before a single offspring is born, called a pup. Individuals reach sexual maturity by age two. While lifespans typically do not exceed six or seven years, some individuals may have extraordinarily long lives. A greater horseshoe bat individual was once banded and then rediscovered thirty years later. Torpor is employed by horseshoe bats in temperate, sub-tropical, and tropical regions. Hibernation is used by horseshoe bats in temperate regions during the winter months. Predators and parasites Overall, bats have few natural predators. Horseshoe bat predators include birds in the order Accipitriformes (hawks, eagles, and kites), as well as falcons and owls. Snakes may also prey on some species while they roost in caves, and domestic cats may hunt them as well. A 2019 study near a colony of bats in central Italy found that 30% of examined cat feces contained the remains of greater horseshoe bats. Horseshoe bats have a variety of internal and external parasites. External parasites (ectoparasites) include mites in the genus Eyndhovenia, "bat flies" of the families Streblidae and Nycteribiidae, ticks of the genus Ixodes, and fleas of the genus Rhinolophopsylla. They are also affected by a variety of internal parasites (endoparasites), including trematodes of the genera Lecithodendrium, Plagiorchis, Prosthodendrium, and cestodes of the genus Potorolepsis. ==Range and habitat==

Horseshoe bats have a mostly Paleotropical distribution, though some species are in the southern Palearctic realm. The greater horseshoe bat has the greatest geographic range of any horseshoe bat, occurring across Europe, North Africa, Japan, China, and southern Asia. Other species are much more restricted, like the Andaman horseshoe bat (R. cognatus), which is only found on the Andaman Islands. ==Relationship to humans==

As disease reservoirs Coronaviruses (R. rouxii) has tested seropositive for Kyasanur Forest disease, which is transmitted to humans by ticks.|alt=A photograph of a horseshoe bat hanging upside down from a rocky surface, with the photographer below the bat. It has shockingly bright orange fur, and dark gray wings, ears, and nose. Horseshoe bats are of particular interest to public health and zoonosis as a source of coronaviruses. Following the 2002–2004 SARS outbreak, several animal species were examined as possible natural reservoirs of the causative coronavirus, SARS-CoV. From 2003 to 2018, forty-seven SARS-related coronaviruses were detected in horseshoe bats. After the SARS outbreak, the least horseshoe bat (R. pusillus) was seropositive, the greater horseshoe bat tested positive for the virus only, and the big-eared horseshoe bat (R. macrotis), Chinese rufous horseshoe bat (R. sinicus), and Pearson's horseshoe bat (R. pearsoni) were both seropositive and tested positive for the virus. The bats' viruses were highly similar to SARS-CoV, with 88–92% similarity. Intraspecies diversity of SARS-like coronaviruses appears to have arisen in Rhinolophus sinicus by homologous recombination. R. sinicus likely harbored the direct ancestor of SARS-CoV in humans. Though horseshoe bats appeared to be the natural reservoir of SARS-related coronaviruses, humans likely became sick through contact with infected masked palm civets, which were identified as intermediate hosts of the virus. indicates that bats were the natural reservoirs of SARS-CoV-2. It is yet unclear how the virus was transmitted to humans, though an intermediate host may have been involved. It was once believed to be the Sunda pangolin, but a July 2020 publication found no evidence of transmission from pangolins to humans. The rufous horseshoe bat (R. rouxii) has tested seropositive for Kyasanur Forest disease, which is a tick-borne viral hemorrhagic fever known from southern India. Kyasanur Forest disease is transmitted to humans through the bite of infected ticks, and has a mortality rate of 2–10%. Longquan virus, a kind of hantavirus, has been detected in the intermediate horseshoe bat, Chinese rufous horseshoe bat, and the little Japanese horseshoe bat (R. cornutus). As food and medicine Microbats are not hunted nearly as intensely as megabats: only 8% of insectivorous species are hunted for food, compared to half of all megabat species in the Old World tropics. Horseshoe bats are hunted for food, particularly in sub-Saharan Africa. Species hunted in Africa include the halcyon horseshoe bat (R. alcyone), Guinean horseshoe bat (R. guineensis), Hill's horseshoe bat (R. hilli), Hills' horseshoe bat (R. hillorum), Maclaud's horseshoe bat (R. maclaudi), the Ruwenzori horseshoe bat, the forest horseshoe bat (R. silvestris), and the Ziama horseshoe bat (R. ziama). In Southeast Asia, Marshall's horseshoe bat (R. marshalli) is consumed in Myanmar and the large rufous horseshoe bat (R. rufus) is consumed in the Philippines. The Ao Naga people of Northeast India are reported to use the flesh of horseshoe bats to treat asthma. Ecological anthropologist Will Tuladhar-Douglas stated that the Newar people of Nepal "almost certainly" use horseshoe bats, among other species, to prepare Cikā Lāpa Wasa ("bat oil"). Dead bats are rolled up and placed in tightly sealed jars of mustard oil; the oil is ready when it gives off a distinct and unpleasant smell. Traditional medicinal uses of the bat oil include removing "earbugs", reported to be millipedes that crawl into one's ears and gnaw at the brain, possibly a traditional explanation of migraines. It is also used as a purported treatment for baldness and partial paralysis. In Senegal, there are anecdotal reports of horseshoe bats being used in potions to treat mental illness; in Vietnam, a pharmaceutical company reported using of horseshoe bat guano each year for medicinal uses. ==Conservation==

As of 2023, the IUCN had evaluated 94 species of horseshoe bat. They have the following IUCN statuses: • Critically endangered: 1 species (Hill's horseshoe bat) • Endangered: 13 species • Vulnerable: 5 species • Near threatened: 9 species • Least concern: 51 species • Data deficient: 15 species Like all cave-roosting bats, cave-roosting horseshoe bats are vulnerable to disturbance of their cave habitats. Disturbance can include mining bat guano, quarrying limestone, and cave tourism. ==References==