Laotian rock rat
Encyclopedia
The Laotian rock rat or kha-nyou (Laonastes aenigmamus), sometimes called the "rat-squirrel", is a rodent
species
of the Khammouan region of Laos
. The species was first described in a 2005 article by Paulina Jenkins and coauthors, who considered the animal to be so distinct from all living rodents that they placed it in a new family
, Laonastidae. It is in the monotypic
genus Laonastes.
In 2006 the classification of the Laotian rock rat was disputed by Mary Dawson
and coauthors. Dawson and her colleagues suggested that instead it belongs to the ancient fossil family Diatomyidae
, that was thought to have been extinct for 11 million years, since the late Miocene
. It would thereby represent a Lazarus taxon
. The animals resemble large dark rat
s with hairy, thick tail
s like those of a squirrel
. Their skull
s are very distinctive and have features that separate them from all other living mammals.
happens periodically, such as with the leaf muntjac
or saola
. The discovery of a completely new family is, by comparison, much more unusual. The most recent incident prior to the discovery of the family Laonastidae of the Laotian rock rat by Western science was the discovery of the bumblebee bat
(Craseonycteris thonglongyai; family Craseonycteridae
) in 1974. The only other examples from the 20th Century are species that are only considered distinct families by a few authorities. These discoveries are: the Chinese River Dolphin (Lipotes vexillifer; family Lipotidae) in 1918, the Zagros mouse-like hamster (Calomyscus bailwardi; family Calomyscidae
) in 1905, and Goeldi's marmoset
(Callimico goeldii
; family Callimiconidae
) in 1904. Representatives from all the remaining rodent families with living representatives (approximately 30) were discovered prior to 1900.
Jenkins et al. (2004) did not compare the specimens to known rodent fossils. After such a comparison, Dawson et al. (2006) were of the opinion that the Laotian rock rat belongs to a previously described family which had only been known from fossils, the Diatomyidae
. The Diatomyidae are known from a series of fossils from the early Oligocene
(~32.5 mya) until the Miocene
(~11 mya). The discovery of the Laotian rock rat means that an 11 million year gap exists in the fossil record where no diatomyids have been found. Dawson et al. (2006) described the Diatomyidae as a Lazarus taxon
due to this gap. The only other comparable length of time for a mammal Lazarus taxon is the monito del monte
, which is part of a family (Microbiotheriidae) also most recently known from Miocene deposits. Mary Dawson described Laonastes as the "coelacanth
of rodents".
The analysis of mtDNA 12S rRNA and cytochrome b
sequence
by Jenkins et al. (2004) allied Laonastes with African hystricognath rodents, namely the blesmol
s and the Dassie Rat
. Support for such a placement was fair, but the exact position could not be resolved. Huchon et al. (2007) conducted a large-scale molecular phylogeny of rodents, including representatives of all major rodent taxonomic groups, based on 5.5 kb of sequence data from four nuclear and two mitochondrial genes, and a short interspersed element insertion analysis including 11 informative loci. Their molecular data place Laonastes robustly as a sister clade
of Ctenodactylidae, and support an ancient divergence during the Lutetian
(Early/Middle Eocene, ~44 mya). The earlier molecular study was in error due to long branch attraction
and inadequate sampling.
λαας = laas = stone, gen: λαος = laos = of stone and Greek
ναστης = nastes = inhabitant). This is in reference to its presence around limestone rocks and also to the country where it was recently discovered. The specific epithet aenigmamus means "enigma mouse" (from Greek αινιγμα = ænigma and μυς = mus, "mouse") referring to its unknown position among the rodents (Jenkins et al., 2004).
in 1996. Remains of three additional animals were obtained in 1998 from villagers and in an owl pellet. Interestingly, the researchers also obtained two additional rodent species and one insectivore
on that expedition that were unknown to science. Scientists were, however, able to assign these animals to known genera (one rodent to Leopoldamys
, and the insectivore to Hylomys
) or a known subfamily (as in the case of Saxatilomys in the rodent subfamily Murinae
).
Return trips to Laos by the Wildlife Conservation Society
researchers have uncovered several other specimens. These new discoveries have prompted the suggestion that the animals may not be as rare as once thought.
On June 13, 2006, David Redfield, a professor emeritus of Florida State University
, and Thai wildlife biologist Uthai Treesucon announced that they had captured, photographed and videotaped a live specimen of the species in the village of Doy in Laos.
s. Their fur is dark slate grey, with a blackish tail. The belly is lighter, with a small whitish area in the center. Their eyes are beady and black. They are about 26 cm (10.2 in) long with a 14 cm (5.5 in) tail and weigh about 400 g (14.1 oz). Jenkins et al. (2004) described the jaw as hystricognathous, but Dawson et al. (2006) argued it is sciurognathous. The infraorbital foramen
is enlarged, consistent with a hystricomorphous zygomasseteric system
. The pterygoid fossa
do not connect to the orbit
, setting them apart from the hystricognathous rodents.
limestone
. They appear to be found only among limestone boulders on hillsides. Villagers in the area are familiar with the animal, calling it kha-nyou, and trapping it for food (Jenkins et al., 2005). The animals are presumed to be nocturnal
.
These rock rats appear to be predominantly herbivore
s, eating leaves
, grass
and seed
s. They may eat insect
s as well, but probably not in high abundance. Females may give birth to a single young (Jenkins et al., 2005).
Laotian rock rats appear to be quite docile and slow moving over open ground. They walk with feet splayed outward in a gait that has been described as duck
-like. Although not ideal for mobility on open surfaces, this appears to be efficient when scrambling up and across large rocks, the sideways angle allowing for greater surface area for feet to find purchase on an angled surface.
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
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 the Khammouan region of Laos
Laos
Laos Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ Sathalanalat Paxathipatai Paxaxon Lao, officially the Lao People's Democratic Republic, is a landlocked country in Southeast Asia, bordered by Burma and China to the northwest, Vietnam to the east, Cambodia to the south and Thailand to the west...
. The species was first described in a 2005 article by Paulina Jenkins and coauthors, who considered the animal to be so distinct from all living rodents that they placed it in a new family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
, Laonastidae. It is in the monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus Laonastes.
In 2006 the classification of the Laotian rock rat was disputed by Mary Dawson
Mary Dawson
Dr. Mary R. Dawson is the curator emeritus of Vertebrate Paleontology at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania. She held the position of curator from 1972 to 2003, and was chair of the Earth Sciences Division from 1973 to 1997....
and coauthors. Dawson and her colleagues suggested that instead it belongs to the ancient fossil family Diatomyidae
Diatomyidae
Diatomyidae is a family of hystricomorphous, sciurognathous rodents found in Asia. It is currently represented by a single known living species, Laonastes aenigmamus.- "Lazarus effect" :...
, that was thought to have been extinct for 11 million years, since the late 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...
. It would thereby represent a Lazarus taxon
Lazarus taxon
In paleontology, a Lazarus taxon is a taxon that disappears from one or more periods of the fossil record, only to appear again later. The term refers to the account in the Gospel of John, in which Jesus raised Lazarus from the dead...
. The animals resemble large dark rat
Rat
Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...
s with hairy, thick tail
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
s like those of a squirrel
Squirrel
Squirrels belong to a large family of small or medium-sized rodents called the Sciuridae. The family includes tree squirrels, ground squirrels, chipmunks, marmots , flying squirrels, and prairie dogs. Squirrels are indigenous to the Americas, Eurasia, and Africa and have been introduced to Australia...
. Their 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...
s are very distinctive and have features that separate them from all other living mammals.
A new family or a Lazarus taxon?
Upon their initial discovery, Jenkins and coauthors (2005) considered the Laotian rock rat to represent a completely new family. The discovery of a new species of an extant mammal 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...
happens periodically, such as with the leaf muntjac
Leaf muntjac
The leaf muntjac, leaf deer or Putao muntjac is a small species of muntjac. It was discovered in 1997 by biologist Alan Rabinowitz during his field study in the isolated Naungmung Township in Myanmar...
or saola
Saola
The Saola, Vu Quang ox or Asian unicorn, also, infrequently, Vu Quang bovid , one of the world's rarest mammals, is a forest-dwelling bovine found only in the Annamite Range of Vietnam and Laos...
. The discovery of a completely new family is, by comparison, much more unusual. The most recent incident prior to the discovery of the family Laonastidae of the Laotian rock rat by Western science was the discovery of the bumblebee bat
Bumblebee Bat
Kitti's Hog-nosed Bat , also known as the bumblebee bat, is a vulnerable species of bat and the only extant member of the family Craseonycteridae. It occurs in western Thailand and southeast Burma, where it occupies limestone caves along rivers.Kitti's Hog-nosed Bat is the smallest species of bat...
(Craseonycteris thonglongyai; family Craseonycteridae
Bumblebee Bat
Kitti's Hog-nosed Bat , also known as the bumblebee bat, is a vulnerable species of bat and the only extant member of the family Craseonycteridae. It occurs in western Thailand and southeast Burma, where it occupies limestone caves along rivers.Kitti's Hog-nosed Bat is the smallest species of bat...
) in 1974. The only other examples from the 20th Century are species that are only considered distinct families by a few authorities. These discoveries are: the Chinese River Dolphin (Lipotes vexillifer; family Lipotidae) in 1918, the Zagros mouse-like hamster (Calomyscus bailwardi; family Calomyscidae
Mouse-like hamster
thumb|200px|rightthumb|200px|right|Mouse-like hamster using its tail for balance while standing on a branch .Mouse-like hamsters are a group of small rodents found in Syria, Azerbaijan, Iran, Turkmenistan, Afghanistan, and Pakistan...
) in 1905, and Goeldi's marmoset
Goeldi's Marmoset
Goeldi's marmoset or Goeldi's monkey is a small, South American New World monkey that lives in the upper Amazon Basin region of Bolivia, Brazil, Colombia, Ecuador, and Peru...
(Callimico goeldii
Goeldi's Marmoset
Goeldi's marmoset or Goeldi's monkey is a small, South American New World monkey that lives in the upper Amazon Basin region of Bolivia, Brazil, Colombia, Ecuador, and Peru...
; family Callimiconidae
Goeldi's Marmoset
Goeldi's marmoset or Goeldi's monkey is a small, South American New World monkey that lives in the upper Amazon Basin region of Bolivia, Brazil, Colombia, Ecuador, and Peru...
) in 1904. Representatives from all the remaining rodent families with living representatives (approximately 30) were discovered prior to 1900.
Jenkins et al. (2004) did not compare the specimens to known rodent fossils. After such a comparison, Dawson et al. (2006) were of the opinion that the Laotian rock rat belongs to a previously described family which had only been known from fossils, the Diatomyidae
Diatomyidae
Diatomyidae is a family of hystricomorphous, sciurognathous rodents found in Asia. It is currently represented by a single known living species, Laonastes aenigmamus.- "Lazarus effect" :...
. The Diatomyidae are known from a series of fossils from the early Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
(~32.5 mya) until 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...
(~11 mya). The discovery of the Laotian rock rat means that an 11 million year gap exists in the fossil record where no diatomyids have been found. Dawson et al. (2006) described the Diatomyidae as a Lazarus taxon
Lazarus taxon
In paleontology, a Lazarus taxon is a taxon that disappears from one or more periods of the fossil record, only to appear again later. The term refers to the account in the Gospel of John, in which Jesus raised Lazarus from the dead...
due to this gap. The only other comparable length of time for a mammal Lazarus taxon is the monito del monte
Monito del Monte
The Monito del Monte The Monito del Monte The Monito del Monte (Spanish for "little mountain monkey", Dromiciops gliroides, is a diminutive marsupial native only to southwestern South America (Chile and Argentina). It is the only extant species in the ancient order Microbiotheria, and the sole New...
, which is part of a family (Microbiotheriidae) also most recently known from Miocene deposits. Mary Dawson described Laonastes as the "coelacanth
Coelacanth
Coelacanths are members of an order of fish that includes the oldest living lineage of Sarcopterygii known to date....
of rodents".
The analysis of mtDNA 12S rRNA and cytochrome b
Cytochrome b
Cytochrome b/b6 is the main subunit of transmembrane cytochrome bc1 and b6f complexes. In addition, it commonly refers to a region of mtDNA used for population genetics and phylogenetics.- Function :...
sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
by Jenkins et al. (2004) allied Laonastes with African hystricognath rodents, namely the blesmol
Blesmol
The blesmols, also known as mole rats, or African mole-rats, are burrowing rodents of the family Bathyergidae. They represent a distinct evolution of a subterranean life among rodents much like the pocket gophers of North America, the tuco-tucos in South America, or the Spalacidae.- Distribution...
s and the Dassie Rat
Dassie Rat
The dassie rat, Petromus typicus, is an African rodent found among rocky outcroppings. It is the only living member of its genus, Petromus, and family, Petromuridae. The name "dassie" means "hyrax" in Afrikaans, and the two animals are found in similar habitats...
. Support for such a placement was fair, but the exact position could not be resolved. Huchon et al. (2007) conducted a large-scale molecular phylogeny of rodents, including representatives of all major rodent taxonomic groups, based on 5.5 kb of sequence data from four nuclear and two mitochondrial genes, and a short interspersed element insertion analysis including 11 informative loci. Their molecular data place Laonastes robustly as a sister clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of Ctenodactylidae, and support an ancient divergence during the Lutetian
Lutetian
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between and . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene subepoch...
(Early/Middle Eocene, ~44 mya). The earlier molecular study was in error due to long branch attraction
Long branch attraction
Long branch attraction is a phenomenon in phylogenetic analyses when rapidly evolving lineages are inferred to be closely related, regardless of their true evolutionary relationships. For example, in DNA sequence-based analyses, the problem arises when sequences from two lineages evolve rapidly...
and inadequate sampling.
Etymology
The genus name for this animal, Laonastes, means "inhabitant of stone" (from GreekGreek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
λαας = laas = stone, gen: λαος = laos = of stone and Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
ναστης = nastes = inhabitant). This is in reference to its presence around limestone rocks and also to the country where it was recently discovered. The specific epithet aenigmamus means "enigma mouse" (from Greek αινιγμα = ænigma and μυς = mus, "mouse") referring to its unknown position among the rodents (Jenkins et al., 2004).
Discovery
The first specimens were found for sale as meat at a market in Thakhek, KhammouanThakhek
Thakhek is a town in south-central Laos on the Mekong River and facing Nakhon Phanom across the river in northeastern Thailand. It is the capital of Khammouane province....
in 1996. Remains of three additional animals were obtained in 1998 from villagers and in an owl pellet. Interestingly, the researchers also obtained two additional rodent species and one insectivore
Insectivora
The order Insectivora is a now-abandoned biological grouping within the class of mammals...
on that expedition that were unknown to science. Scientists were, however, able to assign these animals to known genera (one rodent to Leopoldamys
Leopoldamys
Leopoldamys is a genus of rodent in the family Muridae.It contains the following species:* Sundaic Mountain Long-tailed Giant Rat * Edwards's Long-tailed Giant Rat...
, and the insectivore to Hylomys
Hylomys
Hylomys is a small genus of the family Erinaceidae. Hylomys species, like all species in the subfamily Galericinae, are known as gymnures or moonrats...
) or a known subfamily (as in the case of Saxatilomys in the rodent subfamily Murinae
Murinae
The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. This subfamily is larger than all mammal families except the Cricetidae and Muridae, and is larger than all mammal orders except the bats and the remainder of the...
).
Return trips to Laos by the Wildlife Conservation Society
Wildlife Conservation Society
The Wildlife Conservation Society based at the Bronx Zoo was founded in 1895 as the New York Zoological Society and currently manages some of wild places around the world, with over 500 field conservation projects in 60 countries, and 200 scientists on staff...
researchers have uncovered several other specimens. These new discoveries have prompted the suggestion that the animals may not be as rare as once thought.
On June 13, 2006, David Redfield, a professor emeritus of Florida State University
Florida State University
The Florida State University is a space-grant and sea-grant public university located in Tallahassee, Florida, United States. It is a comprehensive doctoral research university with medical programs and significant research activity as determined by the Carnegie Foundation...
, and Thai wildlife biologist Uthai Treesucon announced that they had captured, photographed and videotaped a live specimen of the species in the village of Doy in Laos.
Description
The animals look generally like rats, with thick, furred tails similar to a squirrel's but limp. The head is large, with round ears and a somewhat bulbous bridge of the nose and very long whiskerWhisker
Whisker may refer to:* an element of box plots* cat's whisker diode, a thin wire used as a contact on a crystal radio receiver* facial hair, hair on the face of a human* vibrissa, a hair on the face of a mammal, used for sensing the surroundings...
s. Their fur is dark slate grey, with a blackish tail. The belly is lighter, with a small whitish area in the center. Their eyes are beady and black. They are about 26 cm (10.2 in) long with a 14 cm (5.5 in) tail and weigh about 400 g (14.1 oz). Jenkins et al. (2004) described the jaw as hystricognathous, but Dawson et al. (2006) argued it is sciurognathous. The infraorbital foramen
Infraorbital foramen
Above the canine fossa is the infraorbital foramen, the end of the infraorbital canal; it transmits the infraorbital artery, vein, and infraorbital nerve.-External links: *...
is enlarged, consistent with a hystricomorphous zygomasseteric system
Zygomasseteric system
The zygomasseteric system in rodents is the anatomical arrangement of the masseter muscle of the jaw and the zygomatic arch of the skull...
. The pterygoid fossa
Pterygoid fossa
The pterygoid fossa is an anatomical term for the fossa formed by the divergence of the lateral pterygoid plate and the medial pterygoid plate of the sphenoid bone.-Structure:...
do not connect to the orbit
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...
, setting them apart from the hystricognathous rodents.
Natural history
Laotian rock rats are found in regions of karstKarst topography
Karst topography is a geologic formation shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite, but has also been documented for weathering resistant rocks like quartzite given the right conditions.Due to subterranean drainage, there...
limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
. They appear to be found only among limestone boulders on hillsides. Villagers in the area are familiar with the animal, calling it kha-nyou, and trapping it for food (Jenkins et al., 2005). The animals are presumed to be nocturnal
Nocturnal animal
Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "nocturnal"....
.
These rock rats appear to be predominantly herbivore
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
s, eating leaves
Leaves
-History:Vocalist Arnar Gudjonsson was formerly the guitarist with Mower, and he was joined by Hallur Hallsson , Arnar Ólafsson , Bjarni Grímsson , and Andri Ásgrímsson . Late in 2001 they played with Emiliana Torrini and drew early praise from the New York Times...
, grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
and seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s. They may eat 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 as well, but probably not in high abundance. Females may give birth to a single young (Jenkins et al., 2005).
Laotian rock rats appear to be quite docile and slow moving over open ground. They walk with feet splayed outward in a gait that has been described as duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
-like. Although not ideal for mobility on open surfaces, this appears to be efficient when scrambling up and across large rocks, the sideways angle allowing for greater surface area for feet to find purchase on an angled surface.
Further reading
- "Oddball Rodent" Found (in Plain View) Is Called New to Science
- Natural History Museum, London: news article including photos.
- CBC.ca Scientists discover new oddball rodent
- Carnegie Museum Press Release: "New family of mammal really living fossil" with images
- CNN: Rat-squirrel is back after 11-million-year absence
- Yahoo! News: "Rat-Squirrel Not Extinct After All"
- Associated Press Report on placing Laonastes in family Diatomyidae
- Environment News Service: "Rodent Discovered in Laos Defines New Family of Mammals" contains photos
- Retired Professor Captures A 'Living Fossil' -- Laotian Rock Rat Once Believed To Have Gone Extinct Florida State University (ScienceDaily) June 14, 2006
External links
- "Living Fossil" captured live on video (Florida State University) June 13, 2006
- Tel Aviv University gene study supports "living fossil" hypothesis