Smallest organism
Encyclopedia
The smallest organism found on Earth
can be measured using a variety of different methods, and can be defined as the smallest by volume
, mass
, height
, or length
. Because there is some dispute over what the definition of life
is and what entities qualify as organism
s, the actual "smallest organism
" (microorganism
s) may be unclear. A further complication is the incomplete nature of scientific knowledge: it is possible that the smallest organism has yet to be discovered.
consider virus
es to be non-living because they lack a cell
ular structure and cannot metabolize
by themselves, requiring a host cell to replicate and synthesise new products. A minority of scientists hold that because viruses do have genetic material and can employ the metabolism of their host, they can be considered organisms. The smallest RNA virus
es in terms of genome
size are small retrovirus
es such as rous sarcoma virus
with genomes of 3.5 kb
and particle diameters of 80 nm
. The smallest DNA virus
es are the hepadnaviruses
such as Hepatitis B, at 3.2 kb and 42 nm; parvovirus
es have smaller capsid
s, at 18-26 nm, but larger genomes, at 5 kb. The smallest DNA bacteriophage
is the Phi-X174 phage
, thought to be larger than Hepatitis B, at about 4 kb. It is important to consider other self replicating genetic elements such as satelliviruses, Viroid
s and Ribozymes.
The Porcine circovirus
type 2 is a single stranded DNA virus having a capsid diameter of 17 nm.
Nanobe
s are thought by some to be the smallest known organism, about one tenth the size of the smallest known bacteria. Nanobes, tiny filamental structures first found in some rocks and sediments, were first described in 1996 by Philippa Uwins of the University of Queensland
is a species of tiny microbe discovered in 2002 in a hydrothermal vent
off the coast of Iceland
by Karl Stetter
. A thermophile
that grows in near-boil
ing temperatures, Nanoarchaeum appears to be an obligatory symbiont
on the archaeon
Ignicoccus
; it must be in contact with the host organism to survive. Its cells are only 400 nm
in diameter, making it the smallest known living organism, with the possible exception of nanobes (if they are considered to be living). Its genome is only 490,885 nucleotides long; as of 2005 it remains the smallest non-viral genome ever sequenced.
, a parasitic
bacterium which lives in the primate
genital and respiratory tracts, is thought to be the smallest known organism capable of independent growth
and reproduction. With a size of approximately 200 to 300 nm, M. genitalium is an ultramicrobacterium
smaller than other small bacteria, including rickettsia
and chlamydia
. However, the vast majority of bacterial strains have not been studied, and the marine ultramicrobacteria Sphingomonas sp strain RB2256 is reported to have passed through 220 nm ultrafilter
. A complicating factor is nutrient-downsized bacteria, bacteria that become much smaller due to a lack of available nutrient
s.
are the smallest free-living eukaryote. The single cell of an Ostreococcus measures only 0.8 μm
across.
mites are among the smallest of all arthropods, measuring only 125 to 250 μm in length.
can be as small as 139 μm long; females are 40 percent larger.
Beetles of the tribe Nanosellini are all less than 1 mm long; the smallest include Scydosella musawasensis at 300 μm long, Vitusella fijiensis at 310 μm, and Nanosella at 300 to 400 μm. These are among the tiniest non-parasitic insects.
, and indeed the smallest arthropod
is the tantulocarid Stygotantulus stocki, at a length of only 94 um.
, and also smallest echinoderm
is Psammothuria ganapatii, a synaptid
which lives between sand grains on the coast of India. Its maximum length is only 4 mm.
, Echinocyamus scaber, has a test
only 6 mm across.
Paedocypris
of Indonesia
, which dwell in peat
swamp
s and can survive extreme drought
in part due to their small size (just 7.9 mm long at maturity). Much of their habitat is acid
water, with pH
as low as 2.9. The members of the genus are thought to be highly endangered.
Male individuals of the species anglerfish
Photocorynus spiniceps
have been documented to be 6.2-7.3 mm at maturity, and thus claimed to be a smaller species. However, these survive only by sexual parasitism
and the female individuals reach the significantly larger size of 50.5 mm.
(Eleutherodactylus iberia) and the Brazilian Gold Frog
(Brachycephalus didactylus) are tied as the smallest frog
, amphibian
, or tetrapod
.
was only 17 millimetre (0.669291338582677 in) .
(Sphaerodactylus ariasae) and the Virgin Islands Dwarf Sphaero (S. parthenopion), two gecko
s in the genus
Sphaerodactylus
, are the world's smallest known reptile
species and smallest lizard, with a snout-vent length of 16 millimetre (0.62992125984252 in). A few Brookesia
chameleons from Madagascar
may be equally small, with a reported snout-vent length of 15–18 mm. for male B. minima
, and 14–19 mm. for male B. tuberculata
, though females are larger.
Of the aforementioned geckos, S. ariasae was first described in 2001 by biologists Blair Hedges and Richard Thomas. This dwarf gecko is endangered
and lives in Jaragua National Park
in the Dominican Republic
and on Beata Island
(Isla Beata), off the southern coast of Hispaniola
in the Dominican Republic
.
is the Speckled Padloper Tortoise
(Homopus signatus) from South Africa
. The males measure 6–8 cm (2.4–3.1 in), while females measure up to almost 10 cm (3.9 in).
(Paleosuchus palpebrosus) from northern and central South America
. It reaches up to 1.6 m (5.2 ft) in length.
(Leptotyphlops carlae). Adults average about 10 cm long, which is only about twice as long as the hatchling
s.
, a genus of feathered dinosaur that lived in what is now China
during the Late Jurassic Period 160 to 155 million years ago. Adult specimens range from 34 cm (13.4 in) long, and the weight has been estimated at up to 110 g (3.9 oz). Nevertheless, sizes of dinosaurs
are commonly labelled with a level of uncertainty, as the available material often (or even usually) is incomplete.
(Mellisuga helenae) is the world's smallest bird
species and the smallest warm-blooded
vertebrate
.
M. helenae, called the zunzún in its native habitat on Cuba
is lighter than a Canadian
or U.S. penny
. It is said that it is "more apt to be mistaken for a bee
than a bird". The Bee Hummingbird is said to eat half its total body mass and drink eight times its total body mass each day. Its nest is 3 cm across.
Kitti's Hog-nosed Bat (bumblebee bat; Craseonycteris thonglongyai) from Thailand
and Myanmar
is the smallest mammal
, at 30–40 mm in length and 1.5 to 2 g in weight.
The Etruscan Shrew is the smallest mammal by mass, though it exceeds the Bumblebee Bat in skull
size. The smallest mammal that ever lived, the shrew-like Batodonoides vanhouteni
, weighed only 1.3 g.
order
is Madame Berthe's Mouse Lemur
(Microcebus berthae), found in Madagascar
, with an average body length of 92 mm (3.6 in).
are the world's smallest flowering plant
s. Fully grown, they measure only 300 µm
by 600 µm and reach a mass of just 150 µg
.
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
can be measured using a variety of different methods, and can be defined as the smallest by volume
Volume
Volume is the quantity of three-dimensional space enclosed by some closed boundary, for example, the space that a substance or shape occupies or contains....
, mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
, height
Height
Height is the measurement of vertical distance, but has two meanings in common use. It can either indicate how "tall" something is, or how "high up" it is. For example "The height of the building is 50 m" or "The height of the airplane is 10,000 m"...
, or length
Length
In geometric measurements, length most commonly refers to the longest dimension of an object.In certain contexts, the term "length" is reserved for a certain dimension of an object along which the length is measured. For example it is possible to cut a length of a wire which is shorter than wire...
. Because there is some dispute over what the definition of life
Life
Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not, either because such functions have ceased , or else because they lack such functions and are classified as inanimate...
is and what entities qualify as organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
s, the actual "smallest organism
Organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...
" (microorganism
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
s) may be unclear. A further complication is the incomplete nature of scientific knowledge: it is possible that the smallest organism has yet to be discovered.
Viruses
Many biologistsBiology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
consider virus
Virus
A virus is a small infectious agent that can replicate only inside the living cells of organisms. Viruses infect all types of organisms, from animals and plants to bacteria and archaea...
es to be non-living because they lack a cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
ular structure and cannot metabolize
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
by themselves, requiring a host cell to replicate and synthesise new products. A minority of scientists hold that because viruses do have genetic material and can employ the metabolism of their host, they can be considered organisms. The smallest RNA virus
RNA virus
An RNA virus is a virus that has RNA as its genetic material. This nucleic acid is usually single-stranded RNA but may be double-stranded RNA...
es in terms of genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
size are small retrovirus
Retrovirus
A retrovirus is an RNA virus that is duplicated in a host cell using the reverse transcriptase enzyme to produce DNA from its RNA genome. The DNA is then incorporated into the host's genome by an integrase enzyme. The virus thereafter replicates as part of the host cell's DNA...
es such as rous sarcoma virus
Rous sarcoma virus
Rous sarcoma virus is a retrovirus and is the first oncovirus to have been described: it causes sarcoma in chickens.As with all retroviruses, it reverse transcribes its RNA genome into cDNA before integration into the host DNA.-History:...
with genomes of 3.5 kb
Base pair
In molecular biology and genetics, the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called a base pair...
and particle diameters of 80 nm
1 E-9 m
To help compare different orders of magnitudes this page lists lengths between 10−9 metres and 10−8 metres .Distances shorter than 1 nanometre*1 nm = 1 nanometre = 1000 picometres = 10 angstroms...
. The smallest DNA virus
DNA virus
A DNA virus is a virus that has DNA as its genetic material and replicates using a DNA-dependent DNA polymerase. The nucleic acid is usually double-stranded DNA but may also be single-stranded DNA . DNA viruses belong to either Group I or Group II of the Baltimore classification system for viruses...
es are the hepadnaviruses
Hepadnaviridae
Hepadnaviruses are a family of viruses which can cause liver infections in humans and animals. There are two recognized genera:*Genus Orthohepadnavirus; type species: Hepatitis B virus...
such as Hepatitis B, at 3.2 kb and 42 nm; parvovirus
Parvovirus
Parvovirus, often truncated to "parvo", is both the common name in English casually applied to all the viruses in the Parvoviridae taxonomic family, and also the taxonomic name of the Parvovirus genus within the Parvoviridae family...
es have smaller capsid
Capsid
A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic...
s, at 18-26 nm, but larger genomes, at 5 kb. The smallest DNA bacteriophage
Bacteriophage
A bacteriophage is any one of a number of viruses that infect bacteria. They do this by injecting genetic material, which they carry enclosed in an outer protein capsid...
is the Phi-X174 phage
Phi-X174 phage
The phi X 174 bacteriophage was the first DNA-based genome to be sequenced. This work was completed by Fred Sanger and his team in 1977. In 1962, Walter Fiers had already demonstrated the physical, covalently closed circularity of phi X 174 DNA.In 2003, it was reported that the whole genome of...
, thought to be larger than Hepatitis B, at about 4 kb. It is important to consider other self replicating genetic elements such as satelliviruses, Viroid
Viroid
Viroids are plant pathogens that consist of a short stretch of highly complementary, circular, single-stranded RNA without the protein coat that is typical for viruses. The smallest discovered is a 220 nucleobase scRNA associated with the rice yellow mottle sobemovirus...
s and Ribozymes.
The Porcine circovirus
Porcine circovirus
Porcine circovirus is a single-stranded DNA virus , that is nonenveloped with an unsegmented circular genome. The viral capsid is icosahedral and approximately 17 nm in diameter. PCV is a member of the virus family Circoviridae....
type 2 is a single stranded DNA virus having a capsid diameter of 17 nm.
Nanobes
Nanobe
A nanobe is a tiny filamental structure first found in some rocks and sediments. Some scientists hypothesize that nanobes are the smallest form of life, 1/10 the size of the smallest known bacteria...
s are thought by some to be the smallest known organism, about one tenth the size of the smallest known bacteria. Nanobes, tiny filamental structures first found in some rocks and sediments, were first described in 1996 by Philippa Uwins of the University of Queensland
University of Queensland
The University of Queensland, also known as UQ, is a public university located in state of Queensland, Australia. Founded in 1909, it is the oldest and largest university in Queensland and the fifth oldest in the nation...
Nanoarchaeum
Nanoarchaeum equitansNanoarchaeum
Nanoarchaeum equitans is a species of tiny microbe, discovered in 2002 in a hydrothermal vent off the coast of Iceland by Karl Stetter. Since it grows in temperatures approaching boiling, it is considered to be a thermophile. Nanoarchaeum appears to be an obligatory symbiont on the archaeon...
is a species of tiny microbe discovered in 2002 in a hydrothermal vent
Hydrothermal vent
A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots. Hydrothermal vents exist because the earth is both...
off the coast of Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...
by Karl Stetter
Karl Stetter
Karl Otto Stetter is a German microbiologist and authority on astrobiology. He is an expert on microbial life at high temperatures.-Career:...
. A thermophile
Thermophile
A thermophile is an organism — a type of extremophile — that thrives at relatively high temperatures, between 45 and 122 °C . Many thermophiles are archaea...
that grows in near-boil
Boil
A boil, also called a furuncle, is a deep folliculitis, infection of the hair follicle. It is always caused by infection by the bacterium Staphylococcus aureus, resulting in a painful swollen area on the skin caused by an accumulation of pus and dead tissue...
ing temperatures, Nanoarchaeum appears to be an obligatory symbiont
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
on the archaeon
Archaea
The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon...
Ignicoccus
Ignicoccus
Ignicoccus is a genus of Archaea living in marine hydrothermal vents. They were discovered in Kolbeinsey Ridge north of Iceland and in the Pacific Ocean in 2000 .-Systematics:...
; it must be in contact with the host organism to survive. Its cells are only 400 nm
Nanometre
A nanometre is a unit of length in the metric system, equal to one billionth of a metre. The name combines the SI prefix nano- with the parent unit name metre .The nanometre is often used to express dimensions on the atomic scale: the diameter...
in diameter, making it the smallest known living organism, with the possible exception of nanobes (if they are considered to be living). Its genome is only 490,885 nucleotides long; as of 2005 it remains the smallest non-viral genome ever sequenced.
Mycoplasma genitalium
Mycoplasma genitaliumMycoplasma genitalium
Mycoplasma genitalium is a small parasitic bacterium that lives on the ciliated epithelial cells of the primate genital and respiratory tracts. M. genitalium is the smallest known genome that can constitute a cell, and the second-smallest bacterium after the recently-discovered endosymbiont...
, a parasitic
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
bacterium which lives in the primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
genital and respiratory tracts, is thought to be the smallest known organism capable of independent growth
Cell growth
The term cell growth is used in the contexts of cell development and cell division . When used in the context of cell division, it refers to growth of cell populations, where one cell grows and divides to produce two "daughter cells"...
and reproduction. With a size of approximately 200 to 300 nm, M. genitalium is an ultramicrobacterium
Ultramicrobacteria
Ultramicrobacteria are bacteria that are considerably smaller than normal bacterial cells and are 0.3 to 0.2 micrometres in diameter. This term was first used in 1981, to refer to cocci in seawater that were less than 0.3 μm in diameter. These cells have also been recovered from soil and appeared...
smaller than other small bacteria, including rickettsia
Rickettsia
Rickettsia is a genus of non-motile, Gram-negative, non-sporeforming, highly pleomorphic bacteria that can present as cocci , rods or thread-like . Being obligate intracellular parasites, the Rickettsia survival depends on entry, growth, and replication within the cytoplasm of eukaryotic host cells...
and chlamydia
Chlamydia (bacterium)
Chlamydia is a genus of bacteria that are obligate intracellular parasites. Chlamydia infections are the most common bacterial sexually transmitted infections in humans and are the leading cause of infectious blindness worldwide....
. However, the vast majority of bacterial strains have not been studied, and the marine ultramicrobacteria Sphingomonas sp strain RB2256 is reported to have passed through 220 nm ultrafilter
Ultrafilter
In the mathematical field of set theory, an ultrafilter on a set X is a collection of subsets of X that is a filter, that cannot be enlarged . An ultrafilter may be considered as a finitely additive measure. Then every subset of X is either considered "almost everything" or "almost nothing"...
. A complicating factor is nutrient-downsized bacteria, bacteria that become much smaller due to a lack of available nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
s.
Eukaryotes
Prasinophyte algae of the genus OstreococcusOstreococcus
Ostreococcus is a genus of unicellular coccoid or spherically shaped green alga belonging to the class Prasinophyceae. It includes prominent members of the global picoplankton community, which plays a central role in the oceanic carbon cycle.-History:...
are the smallest free-living eukaryote. The single cell of an Ostreococcus measures only 0.8 μm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
across.
Smallest arachnid
EriophyidEriophyid
Eriophyidae is a family of more than 200 genera of mites, which live as plant parasites, commonly causing galls or other damage to the plant tissues and hence known as gall mites. About 3,600 species have been described, but this is probably less than 10% of the actual number existing in this...
mites are among the smallest of all arthropods, measuring only 125 to 250 μm in length.
Smallest insect
Adult males of the parasitic wasp Dicopomorpha echmepterygisDicopomorpha echmepterygis
Dicopomorpha echmepterygis is a parasitic wasp in the family Mymaridae. The males of this species are the smallest of all known insects. They are blind and wingless and may be no more than 0.139 mm in length . Females are 40% larger...
can be as small as 139 μm long; females are 40 percent larger.
- Smallest beetle
Beetles of the tribe Nanosellini are all less than 1 mm long; the smallest include Scydosella musawasensis at 300 μm long, Vitusella fijiensis at 310 μm, and Nanosella at 300 to 400 μm. These are among the tiniest non-parasitic insects.
Smallest crustacean
The smallest crustaceanCrustacean
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...
, and indeed the smallest arthropod
Arthropod
An arthropod is an invertebrate animal having an exoskeleton , a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda , and include the insects, arachnids, crustaceans, and others...
is the tantulocarid Stygotantulus stocki, at a length of only 94 um.
Echinoderms
The smallest sea cucumberSea cucumber
Sea cucumbers are echinoderms from the class Holothuroidea.They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. There are a number of holothurian species and genera, many of which are targeted...
, and also smallest echinoderm
Echinoderm
Echinoderms are a phylum of marine animals. Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone....
is Psammothuria ganapatii, a synaptid
Synaptidae
Synaptidae is a family of sea cucumber that have no tube feet, tentacle ampullae, retractor muscles, respiratory trees, or cuvierian organs. They also lack radial canals of the water-vascular system, with only the circumoral ring present....
which lives between sand grains on the coast of India. Its maximum length is only 4 mm.
Sea urchins
The smallest sea urchinSea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...
, Echinocyamus scaber, has a test
Test (biology)
A test is a term used to refer to the shell of sea urchins, and also the shell of certain microorganisms, such as testate foraminifera and testate amoebae....
only 6 mm across.
Vertebrates
The smallest vertebrates (and smallest fishes) known are part of the genusGenus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Paedocypris
Paedocypris
Paedocypris is a genus of cyprinid fish found in Southeast Asia where it occurs in Malaysia and Indonesia. Three species are known.Paedocypris progenetica has been claimed to be the smallest known species of fish and vertebrate in the world...
of Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, which dwell in peat
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
s and can survive extreme drought
Drought
A drought is an extended period of months or years when a region notes a deficiency in its water supply. Generally, this occurs when a region receives consistently below average precipitation. It can have a substantial impact on the ecosystem and agriculture of the affected region...
in part due to their small size (just 7.9 mm long at maturity). Much of their habitat is acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
water, with pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
as low as 2.9. The members of the genus are thought to be highly endangered.
Male individuals of the species anglerfish
Anglerfish
Anglerfishes are members of the teleost order Lophiiformes . They are bony fishes named for their characteristic mode of predation, wherein a fleshy growth from the fish's head acts as a lure; this is considered analogous to angling.Some anglerfishes are pelagic , while others are benthic...
Photocorynus spiniceps
Photocorynus spiniceps
Photocorynus spiniceps is a species of anglerfish in the family Linophrynidae. It is in the monotypic genus Photocorynus.The known mature male individuals are 6.2–7.3 millimeters , smaller than any other mature fish and vertebrate; the females, however, reach a significantly larger size of up...
have been documented to be 6.2-7.3 mm at maturity, and thus claimed to be a smaller species. However, these survive only by sexual parasitism
Brood parasite
Brood parasites are organisms that use the strategy of brood parasitism, a kind of kleptoparasitism found among birds, fish or insects, involving the manipulation and use of host individuals either of the same or different species to raise the young of the brood-parasite...
and the female individuals reach the significantly larger size of 50.5 mm.
Smallest amphibian
At 9.6 to 9.8 mm (0.377952755905512 to 0.385826771653543 in) long, the Monte Iberia EleuthMonte Iberia Eleuth
The Monte Iberia Eleuth is the smallest living frog in the northern hemisphere, ranging between in length. It is the second-smallest frog in the world, following the Brazilian Gold Frog. It was first discovered in 1996 on Mount Iberia, from which the animal gets its name, and exists in only two...
(Eleutherodactylus iberia) and the Brazilian Gold Frog
Brazilian Gold Frog
The Brazilian gold frog , also known as Izecksohn's toad, is the smallest frog in the Southern Hemisphere. It was previously called Psyllophryne didactyla....
(Brachycephalus didactylus) are tied as the smallest frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
, amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
, or tetrapod
Tetrapod
Tetrapods are vertebrate animals having four limbs. Amphibians, reptiles, birds and mammals are all tetrapods; even snakes and other limbless reptiles and amphibians are tetrapods by descent. The earliest tetrapods evolved from the lobe-finned fishes in the Devonian...
.
Smallest salamander
The average length of several specimens of the salamander Thorius arboreusThorius arboreus
Thorius arboreus is a species of salamander in the Plethodontidae family.It is endemic to Mexico.Its natural habitat is subtropical or tropical moist montanes.It is threatened by habitat loss.It is the smallest species of all salamanders.-References:...
was only 17 millimetre (0.669291338582677 in) .
Smallest reptile
The Jaragua SphaeroJaragua Sphaero
Sphaerodactylus ariasae, the Jaragua Sphaero or dwarf gecko, is a very small Gekkonidae species in the Sphaerodactylus genus. It is one of the world's two smallest known reptiles...
(Sphaerodactylus ariasae) and the Virgin Islands Dwarf Sphaero (S. parthenopion), two gecko
Gecko
Geckos are lizards belonging to the infraorder Gekkota, found in warm climates throughout the world. They range from 1.6 cm to 60 cm....
s in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Sphaerodactylus
Sphaerodactylus
Sphaerodactylus is a genus of geckos from the Americas that are distinguished from other gekkoninae by their small size and round, rather than vertical eye pupils and each digit terminating in a single, round adhesive pad or scale, from which their name is derived. All species in this genus are...
, are the world's smallest known reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
species and smallest lizard, with a snout-vent length of 16 millimetre (0.62992125984252 in). A few Brookesia
Brookesia
Brookesia is a genus of chameleons found in Madagascar, that range from small to very small in size, and are known collectively as Leaf Chameleons . It includes the species considered to be the world's smallest chameleons, and are also among the smallest reptiles...
chameleons from Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
may be equally small, with a reported snout-vent length of 15–18 mm. for male B. minima
Brookesia minima
Brookesia minima, , is a diminutive chameleon "often said to be the smallest" or "probably the smallest" of the Chamaeleonidae.-Range:B...
, and 14–19 mm. for male B. tuberculata
Brookesia tuberculata
Brookesia tuberculata is a diminutive chameleon from far northern Madagascar.-Similar species:A 1999 paper in the Journal of Zoology disputed a 1995 paper which considered this species and B. peyrierasi to be the same species as B. minima...
, though females are larger.
Of the aforementioned geckos, S. ariasae was first described in 2001 by biologists Blair Hedges and Richard Thomas. This dwarf gecko is endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
and lives in Jaragua National Park
Jaragua National Park
Jaragua National Park is a national park of the Dominican Republic. Jaragua National Park is located in Pedenales Province in the extreme southwest of the Dominican Republic...
in the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
and on Beata Island
Beata Island
Beata Island is a small island on the Caribbean Sea, located 7 km southwest from cape Beata, the southernmost point of the island Hispaniola. Some 12 km SW of it lies the smaller Alto Velo Island...
(Isla Beata), off the southern coast of Hispaniola
Hispaniola
Hispaniola is a major island in the Caribbean, containing the two sovereign states of the Dominican Republic and Haiti. The island is located between the islands of Cuba to the west and Puerto Rico to the east, within the hurricane belt...
in the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
.
Smallest turtle
The world's smallest turtleTurtle
Turtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...
is the Speckled Padloper Tortoise
Speckled Padloper Tortoise
The speckled padloper or speckled Cape tortoise is the world’s smallest tortoise. It is endemic to South Africa....
(Homopus signatus) from South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
. The males measure 6–8 cm (2.4–3.1 in), while females measure up to almost 10 cm (3.9 in).
Smallest crocodilian
The smallest crocodilian is the Cuvier's Dwarf CaimanCuvier's Dwarf Caiman
The Cuvier's dwarf caiman or Musky caiman, Paleosuchus palpebrosus, is a relatively small crocodilian reptile from northern and central South America. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Surinam and Venezuela...
(Paleosuchus palpebrosus) from northern and central South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. It reaches up to 1.6 m (5.2 ft) in length.
Smallest snake
One of the smallest snakes known is the recently discovered Barbados ThreadsnakeBarbados Threadsnake
Barbados Threadsnake is a species of blind threadsnake. It is the smallest snake species currently known to exist. This member of the Leptotyphlopidae family is found on the Caribbean island of Barbados....
(Leptotyphlops carlae). Adults average about 10 cm long, which is only about twice as long as the hatchling
Hatchling
In oviparous biology, a hatchling is the newborn of animals that develop and emerge from within hard-shell eggs. The offspring of birds are often hatched naked and with their eyes closed. The hatchling relies totally on its parents for feeding and warmth. Hatchlings precede nestlings in the chick's...
s.
Smallest non-avian dinosaur
The smallest known non-avian dinosaur is AnchiornisAnchiornis
Anchiornis is a genus of small, feathered, deinonychosaurian dinosaur. The genus Anchiornis contains the type species Anchiornis huxleyi, named in honor of Thomas Henry Huxley, an early proponent of biological evolution, and the first to propose a close evolutionary relationship between birds and...
, a genus of feathered dinosaur that lived in what is now China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
during the Late Jurassic Period 160 to 155 million years ago. Adult specimens range from 34 cm (13.4 in) long, and the weight has been estimated at up to 110 g (3.9 oz). Nevertheless, sizes of dinosaurs
Dinosaur size
Size has been one of the most interesting aspects of dinosaur science to the general public. This article lists the largest and smallest dinosaurs from various groups, sorted in order of weight and length....
are commonly labelled with a level of uncertainty, as the available material often (or even usually) is incomplete.
Smallest bird
With a mass of approximately 1.8 gram (0.0634931317892015 oz) and a length of 5 centimetres (2.0 in), the Bee HummingbirdBee Hummingbird
The Bee Hummingbird or Zunzuncito is a species of hummingbird that is endemic to Cuba and Isla de la Juventud...
(Mellisuga helenae) is the world's smallest bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
species and the smallest warm-blooded
Warm-blooded
The term warm-blooded is a colloquial term to describe animal species which have a relatively higher blood temperature, and maintain thermal homeostasis primarily through internal metabolic processes...
vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
.
M. helenae, called the zunzún in its native habitat on Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
is lighter than a Canadian
Penny (Canadian coin)
In Canada, a penny is a coin worth one cent or of a dollar. According to the Royal Canadian Mint, the official national term of the coin is the "one-cent piece", but in practice the term penny or cent is universal. Originally, "penny" referred to a two-cent coin. When the two-cent coin was...
or U.S. penny
Cent (United States coin)
The United States one-cent coin, commonly known as a penny, is a unit of currency equaling one one-hundredth of a United States dollar. The cent's symbol is ¢. Its obverse has featured the profile of President Abraham Lincoln since 1909, the centennial of his birth. From 1959 to 2008, the reverse...
. It is said that it is "more apt to be mistaken for a bee
Bee
Bees are flying insects closely related to wasps and ants, and are known for their role in pollination and for producing honey and beeswax. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila...
than a bird". The Bee Hummingbird is said to eat half its total body mass and drink eight times its total body mass each day. Its nest is 3 cm across.
Smallest mammal
The vulnerableVulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
Kitti's Hog-nosed Bat (bumblebee bat; Craseonycteris thonglongyai) from Thailand
Thailand
Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
and Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
is the smallest mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
, at 30–40 mm in length and 1.5 to 2 g in weight.
The Etruscan Shrew is the smallest mammal by mass, though it exceeds the Bumblebee Bat in 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...
size. The smallest mammal that ever lived, the shrew-like Batodonoides vanhouteni
Batodonoides vanhouteni
Batodonoides vanhouteni is an extinct shrew-like mammal, thought to be the smallest mammal that ever lived. Based on the size of its molar teeth, it is estimated that Batodonoides vanhouteni weighed only...
, weighed only 1.3 g.
Smallest primate
The smallest member of the primatePrimate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
is Madame Berthe's Mouse Lemur
Madame Berthe's Mouse Lemur
Madame Berthe's mouse lemur or Berthe's mouse lemur is the smallest of the mouse lemurs and the smallest primate in the world; the average body length is and seasonal weight is around...
(Microcebus berthae), found in Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, with an average body length of 92 mm (3.6 in).
Smallest angiosperms
Duckweeds of the genus WolffiaWolffia
Wolffia is a genus of 9 to 11 species which include the smallest flowering plants on Earth. Commonly called watermeal or duckweed, these aquatic plants resemble specks of cornmeal floating on the water. Wolffia species are free-floating thalli, green or yellow-green, and without roots. The flower...
are the world's smallest flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s. Fully grown, they measure only 300 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
by 600 µm and reach a mass of just 150 µg
Microgram
In the metric system, a microgram is a unit of mass equal to one millionth of a gram , or 1/1000 of a milligram. It is one of the smallest units of mass commonly used...
.
External links
- featherwing beetles on the UFUniversity of FloridaThe University of Florida is an American public land-grant, sea-grant, and space-grant research university located on a campus in Gainesville, Florida. The university traces its historical origins to 1853, and has operated continuously on its present Gainesville campus since September 1906...
/ IFASInstitute of Food and Agricultural SciencesThe University of Florida’s Institute of Food and Agricultural Sciences is a federal-state-county partnership dedicated to developing knowledge in agriculture, human and natural resources, and the life sciences, and enhancing and sustaining the quality of human life by making that information...
Featured Creatures Web site