Myotis vivesi, the fish-eating bat or fish-eating myotis, is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of bat

Bat

Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

 that lives around the Gulf of California

Gulf of California

The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...

, and feeds on fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 and crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s. It is the largest species of the genus Myotis

Mouse-eared bat

The mouse-eared bats are a diverse and widespread genus of bats within the family Vespertilionidae.-Relationships:Myotis has historically been included in the subfamily Vespertilioninae, but was classified in its own subfamily, Myotinae, by Nancy Simmons in 1998...

in the Americas, and has exceptionally large feet, which it uses in hunting. It was described in 1901 by Auguste Ménégaux

Auguste Ménégaux

Henri Auguste Ménégaux was a French ornithologist and malacologist. He was based at the Muséum national d'histoire naturelle in Paris. In 1909 he was a cofounder, and subsequent editor, of the journal Revue Française d'Ornithologie.-References:...

 and is the only species in the subgenus (or genus) Pizonyx.

Description

Myotis vivesi is the largest species in the genus Myotis in the Americas

Americas

The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...

, and is similar in size to the Eurasia

Eurasia

Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

n Myotis myotis

Greater mouse-eared bat

The greater mouse-eared bat, Myotis myotis, is a European species of bat in the Vespertilionidae family.-Description:It is relatively large for a member of the Myotis genus, weighing up to , making it one of the largest European bats.-Foraging:Like its relatives it eats various arthropods;...

(greater mouse-eared bat). The skull

Skull

The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

 averages 23 millimetre (0.905511811023622 in) in length. The second largest Myotis species in the New World, Myotis velifer

Cave Myotis

The Cave Myotis is a species of vesper bat in the Vespertilionidae family.It is found in Belize, El Salvador, Guatemala, Honduras, Mexico and in the southwest United States....

, has a skull 17.6 mm (0.692913385826772 in) long, and feet 8 mm (0.31496062992126 in) long; M. vivesi has greatly elongated hind feet, which average 23 mm (0.905511811023622 in) long.

In common with other fish-eating bats, Myotis vivesi has long, efficient wings, with high aspect ratio

Aspect ratio (wing)

In aerodynamics, the aspect ratio of a wing is essentially the ratio of its length to its breadth . A high aspect ratio indicates long, narrow wings, whereas a low aspect ratio indicates short, stubby wings....

 and low wing loading

Wing loading

In aerodynamics, wing loading is the loaded weight of the aircraft divided by the area of the wing. The faster an aircraft flies, the more lift is produced by each unit area of wing, so a smaller wing can carry the same weight in level flight, operating at a higher wing loading. Correspondingly,...

, and large feet with sharp claws. The uropatagium (the wing surface between the hind legs) bears a fringe of silky hairs of unknown function; the uropatagium itself is used in hunting.

The fur

Fur

Fur is a synonym for hair, used more in reference to non-human animals, usually mammals; particularly those with extensives body hair coverage. The term is sometimes used to refer to the body hair of an animal as a complete coat, also known as the "pelage". Fur is also used to refer to animal...

 is around 8 mm (0.31496062992126 in) long, and varies in colour from fawn to brown, with the base of each hair being dark grey. In common with other piscivorous species of Myotis, the underside of M. vivesi is pale.

Distribution

Myotis vivesi is found along the coast of the Gulf of California

Gulf of California

The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...

 in the Mexican

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 states of Sonora

Sonora

Sonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....

, Baja California

Baja California

Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...

 and Baja California Sur

Baja California Sur

Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...

, mostly on small islands. A small population exists on the Pacific

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 coast of the Baja California peninsula

Baja California Peninsula

The Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...

, between Isla Encantada and Punta Coyote. Since it lives on small islands, the range

Range (biology)

In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...

 of M. vivesi is naturally fragmented

Habitat fragmentation

Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...

, but data from microsatellites and the mtDNA control region

MtDNA control region

The mtDNA control region is an area of the mitochondrial genome which is non-coding DNA. It is the most polymorphic region of the human mtDNA genome, with polymorphism concentrated in hypervariable regions. The average nucleotide diversity in these regions is 1.7%...

 indicate that there is no isolation by distance

Isolation by distance

Isolation by distance describes the tendency of individuals to find mates from nearby populations rather than distant populations. As a result of this tendency, populations that live near each other are genetically more similar than populations that live further apart. Isolation by distance results...

 in the species.

Ecology and behaviour

Myotis vivesi feeds chiefly on marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 or crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s, including the squat lobster

Squat lobster

Squat lobsters are decapod crustaceans of the families Galatheidae, Chirostylidae and Kiwaidae, including the common genera Galathea and Munida. They are not lobsters at all, but are more closely related to porcelain crabs, hermit crabs and then, more distantly, true crabs...

 Pleuroncodes planipes

Pleuroncodes planipes

Pleuroncodes planipes, sometimes called the pelagic red crab , tuna crab or , is a species of squat lobster from the eastern Pacific Ocean.-Description:...

. Only one other bat species, Noctilio leporinus

Greater Bulldog Bat

The greater bulldog bat or fisherman bat is a type of fishing bat native to Latin America. The bat uses echolocation to detect water ripples made by the fish upon which it preys, then uses the pouch between its legs to scoop the fish up and its sharp claws to catch and cling to it...

, hunts in marine waters.
The guano

Guano

Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...

 produced by M. vivesi is red if it has eaten crustaceans, and black if it has eaten fish; green guano and brown guano result from feeding on algae and insects, respectively. As well as fish and crustaceans, M. vivesi also feeds occasionally on aerial insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s. M. vivesi can cover large distances when hunting; in 1970, scientists saw "a group of about 400 M. vivesi around a boat at least 7 km [4.3 miles] from the shore". M. vivesi inhabits an arid environment and has evolved the ability to concentrate its urine

Urine

Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...

; this allows it to survive by drinking seawater

Seawater

Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...

.

M. vivesi prefers to roost either in cave

Cave

A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...

s or under rocks revealed by landslide

Landslide

A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...

s. They sometimes share their roosts with least petrels

Least Storm-petrel

The Least Storm Petrel is a small seabird of the storm-petrel family Hydrobatidae. It is 13–15 cm in length, with a wingspan of 32 cm. It is the smallest member of the order Procellariiformes...

 (Halocyptena microsoma) and black petrels

Black Storm-petrel

The Black Storm Petrel is a small seabird of the storm-petrel family Hydrobatidae. It is 23 cm in length, with a wingspan of 46–51 cm....

 (Oceanodroma melania).

Taxonomy and evolution

Myotis vivesi was first described

Alpha taxonomy

Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...

 by Auguste Ménégaux

Auguste Ménégaux

Henri Auguste Ménégaux was a French ornithologist and malacologist. He was based at the Muséum national d'histoire naturelle in Paris. In 1909 he was a cofounder, and subsequent editor, of the journal Revue Française d'Ornithologie.-References:...

 in 1901. The species was moved to a new genus, Pizonyx by Gerrit Smith Miller

Gerrit Smith Miller

Gerrit Smith Miller, Jr. was an American zoologist.He was born in Peterboro, New York in 1869. He graduated from Harvard University in 1894 and worked under Clinton Hart Merriam at the United States Department of Agriculture...

 in 1906, but that taxon is now usually included in Myotis. Ménégaux gave no indication of the etymology

Etymology

Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...

 of the specific name vivesi; it may either refer to a person called Vives, or derive from the Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 verb vivere, "to live". If Vives was a person, he was not the collector of the specimens, that being recorded as Léon Diguet. No subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of M. vivesi have been recognised.

The closest relatives of M. vivesi are other New World species of Myotis which are not adapted to piscivory, rather than the other piscivorous bats in the genus. This indicates that the adaptation

Adaptation

An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....

s to catching fish in M. vivesi and other species are the result of convergent evolution

Convergent evolution

Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

. No fossils attributable to M. vivesi have been discovered. A fossil species of Pizonyx, Pizonyx wheeleri, was named by Walter Dalquest and Daniel Patrick in 1993 from the Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

 of Texas, but according to a 1993 review by Nicholas Czaplewski, this species instead belongs to the genus Antrozous and may not even be distinct from the living species Antrozous pallidus.