Spix’s disk-winged bat (''Thyroptera tricolor''), is a species of bat in the family

Thyropteridae Disk-winged bats are a small group of bats of the family Thyropteridae and genus ''Thyroptera''. They are found in Central and South America, usually in moist tropical rain forests. It is a very small family, consisting of a single genus with f ...

. It is native to the Americas from

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

. The most prominent anatomical feature of this bat, which distinguishes it from other species, is the disks on its thumbs and hind feet. These circular disks act as suction cups, allowing the bats to cling onto and move along smooth surfaces.

Distribution and habitat

Spix's disk-winged bat is distributed in the nations of

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

Tobago Tobago, officially the Ward of Tobago, is an List of islands of Trinidad and Tobago, island and Regions and municipalities of Trinidad and Tobago, ward within the Republic of Trinidad and Tobago. It is located northeast of the larger islan ...

Trinidad Trinidad is the larger, more populous island of the Republic of Trinidad and Tobago, the country. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is the southernmost island in ...

Suriname Suriname, officially the Republic of Suriname, is a country in northern South America, also considered as part of the Caribbean and the West Indies. It is a developing country with a Human Development Index, high level of human development; i ...

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

Panama Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...

Guyana Guyana, officially the Co-operative Republic of Guyana, is a country on the northern coast of South America, part of the historic British West Indies. entry "Guyana" Georgetown, Guyana, Georgetown is the capital of Guyana and is also the co ...

Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. It is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, ...

French Guiana French Guiana, or Guyane in French, is an Overseas departments and regions of France, overseas department and region of France located on the northern coast of South America in the Guianas and the West Indies. Bordered by Suriname to the west ...

Costa Rica Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

Belize Belize is a country on the north-eastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a maritime boundary with Honduras to the southeast. P ...

, and

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

. It has a patchy distribution but a very wide range, and it is considered to be a

least-concern species A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

by the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

(IUCN).

Species abundance In ecology, local abundance is the relative representation of a species in a particular ecosystem. It is usually measured as the number of individuals found per sample. The ratio of abundance of one species to one or multiple other species livin ...

of the bat may be limited by the availability of roosting sites. Whereas other species of bats are capable of aggregating in large numbers, hanging head-down by their toes from cave ceilings and hollow trees, ''T. tricolor'' is adapted to roosting in furled leaves, and its populations may be limited by the abundance of plants with this feature.

Description

Spix’s disk-winged bat has a white or pale yellow underbelly and a reddish-brown to black dorsal surface. In a survey of this species individuals had an average forearm length of and for females and males, respectively. The adult weighs about . EB1911 Chiroptera Fig

Unlike most bats, ''T. tricolor'' clings head-up from its roost. This phenomenon is observed in six bat species in two genera, ''Thyroptera'' and '' Myzopoda''. The former are known as disk-winged, and the latter as sucker-footed. The two groups represent an occurrence of the

parallel evolution Parallel evolution is the similar development of a trait in distinct species that are not closely related, but share a similar original trait in response to similar evolutionary pressure.Zhang, J. and Kumar, S. 1997Detection of convergent and pa ...

of a feature, but the two forms of adhesive anatomy are utilized differently. The disk-winged bat seeks a bud of rolled-up leaves with the opening at the top. It clings head-up to the smooth inner (ventral) surfaces of the leaves. Plants with this leaf morphology include '' Heliconia'' and '' Calathea'' species. This manner of roosting is said to facilitate rapid escape in the event of a potential disturbance. The bat’s disks take the shape of concave cups, and are supported by an internal cartilaginous plate. The

flexor pollicis brevis muscle The flexor pollicis brevis is a muscle in the hand that flexes the thumb. It is one of three thenar muscles. It has both a superficial part and a deep part. Origin and insertion The muscle's superficial head arises from the distal edge of the f ...

attaches to the plate, such that contraction of the muscle alters overall disk shape, creating suction. In order to maintain the integrity of the disk the bat grooms it frequently by licking it. The disk also contains abundant sweat glands, maintaining a moist surface. The

Madagascar sucker-footed bat The Madagascar sucker-footed bat, Old World sucker-footed bat, or simply sucker-footed bat (''Myzopoda aurita'') is a species of bat in the family Myzopodidae endemic to Madagascar, especially in the eastern part of the forests. The genus was tho ...

(''Myzopoda aurita'') has similar sucker anatomy, but produces suction differently. It uses its flexor muscle to change the shape of the disk when detaching from a surface. It also uses sweat lubrication to produce wet adhesion as the main mechanism, rather than suction. It can only attach head-up, while the disk-winged bat can cling at any angle. ''M. aurita'' can concurrently make contact with both its adhesive organ and thumb claw, whereas ''T. tricolor'' cannot. This may be due to the difference in the anatomy of the muscle insertions and the actions they bring about.

Behavior

The species roosts communally. The mean colony size is six individuals and colonies have a sex ratio of 1:1. The disks do not prevent agile flight, and bats may circle furled leaves they seek to enter. They fly just a few meters above the forest floor. The species is

insectivorous A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant which eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores we ...

, with adults consuming up to of insects per night.

References

{{Taxonbar, from=Q1829302 Thyropteridae Mammals of Colombia Bats of Central America Mammals described in 1823