Yinotheria is a proposed basal subclass clade of crown
mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
uniting the
Shuotheriidae
Shuotheriidae is a small family of Jurassic mammals whose remains are found in China, England and possibly Russia. They have been proposed to be close relatives of Australosphenida, the group that contains living monotremes, together forming the ...
, an extinct group of mammals from the Jurassic of Eurasia, with
Australosphenida
The Australosphenida are a clade of mammals, containing mammals with tribosphenic molars, known from the Jurassic to Mid-Cretaceous of Gondwana. They are thought to have acquired their tribosphenic molars independently from those of Tribosphenida ...
, a group of mammals known from the Jurassic to Cretaceous of
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...
, which possibly include living
monotremes
Monotremes () are prototherian mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals (Eutheria), and marsupials (Metatheria). Monotremes are typified by structural differences in their brains, ...
.
Today, there are only five surviving
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of monotremes which live in
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
and
New Guinea
New Guinea (; Hiri Motu
Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea).
It is a simplified version of ...
, consisting of the
platypus
The platypus (''Ornithorhynchus anatinus''), sometimes referred to as the duck-billed platypus, is a semiaquatic, egg-laying mammal Endemic (ecology), endemic to Eastern states of Australia, eastern Australia, including Tasmania. The platypu ...
and four species of
echidna
Echidnas (), sometimes known as spiny anteaters, are quill-covered monotremes (egg-laying mammals) belonging to the family Tachyglossidae . The four extant species of echidnas and the platypus are the only living mammals that lay eggs and the ...
. Fossils of yinotheres have been found in
England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
,
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
,
Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
,
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
and
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. Contrary to other known crown mammals, they retained postdentary bones as shown by the presence of a postdentary trough. The extant members (monotremes) developed the mammalian
middle ear
The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear).
The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the ...
independently.
Evolutionary history
According to genetic studies, Yinotheria diverged from other
mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s around 220 to 210 million years ago, at some point in the
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
or
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-J ...
.
[http://timetree.org/pdf/Madsen2009Chap68.pdf ] The oldest-known fossils are a bit younger, dating around 168 to 163 million years in the
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...
. These fossils are the genera ''
Pseudotribos
''Pseudotribos'' ("false chewing") is an extinct genus of mammal that lived in Northern China during the Middle Jurassic some , possibly more closely related to monotremes than to theria (placental and marsupial mammals), although other studies i ...
'' of China,
''
Shuotherium
''Shuotherium'' is a fossil mammal known from Middle-Late Jurassic of the Forest Marble Formation of England,Sigogneau−Russell, D. 1998. Discovery of a Late Jurassic Chinese mammal
in the upper Bathonian of England. Comptes Rendus de l’Acad ...
'' of both China and England, ''
Itatodon
''Itatodon'' is an extinct genus of primitive mammal known from the Bathonian aged Itat Formation of Russia. The genus is named after the formation, with the species being named after Leonid Petrovich Tatarinov who described the first docodont
fr ...
'' of
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...
and ''
Paritatodon
''Paritatodon'' is an extinct mammal which existed in Kyrgyzstan and England during the Jurassic period. It was originally the holotype specimen of ''Shuotherium kermacki'', but Martin and Averianov (2010) argued that it resembled the genus ''It ...
'' of
Kyrgyzstan
Kyrgyzstan,, pronounced or the Kyrgyz Republic, is a landlocked country in Central Asia. Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the south, and the People's Republic of China to the east. ...
and
England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
. These, which belong to the family
Shuotheriidae
Shuotheriidae is a small family of Jurassic mammals whose remains are found in China, England and possibly Russia. They have been proposed to be close relatives of Australosphenida, the group that contains living monotremes, together forming the ...
, are the only known northern hemisphere group of yinotherians.
The infraclass
Australosphenida
The Australosphenida are a clade of mammals, containing mammals with tribosphenic molars, known from the Jurassic to Mid-Cretaceous of Gondwana. They are thought to have acquired their tribosphenic molars independently from those of Tribosphenida ...
appeared around the same time as Shuotheriidae. The family
Henosferidae
Henosferidae (also spelled "Henospheridae") is an extinct family of Australosphenida, native to Gondwana during the Middle Jurassic. Its defined as a clade including the most recent common ancestor of ''Henosferus'' and ''Asfaltomylos
''Asf ...
, comprising the genera ''
Henosferus
''Henosferus'' is an extinct genus of australosphenidan mammal from Lower Jurassic of Argentina. The only recorded species, ''Henosferus molus'', was found in the Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Chubut Province
Chu ...
'', ''
Ambondro'', and ''
Asfaltomylos
''Asfaltomylos'' is an extinct genus of the primitive mammal subclass Australosphenida from the Jurassic of Argentina. The type and only species is ''Asfaltomylos patagonicus'', recovered from and named after the Cañadón Asfalto Formation, Caà ...
'', has been found in the southern hemisphere at locations in Argentina and Madagascar. This suggests that this family could have been more widespread and diverse in
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...
during that time; however, due to their fragile state, some fossils might have been destroyed by geological events.
The family
Ausktribosphenidae
Ausktribosphenidae is an extinct family of australosphenidan mammals from the Early Cretaceous of Australia and mid Cretaceous of South America.
Classification and taxonomy
Ausktribosphenidae is closely related to monotremes and hence the two f ...
and the first
monotreme
Monotremes () are prototherian mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals (Eutheria), and marsupials (Metatheria). Monotremes are typified by structural differences in their brain ...
s appeared in the
Early Cretaceous
The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma.
Geology
Pro ...
, in the region that is now known as
Australasia
Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologica ...
. Despite being found in the same region of the world and in the same time period, recent work has found that the older
Henosferidae
Henosferidae (also spelled "Henospheridae") is an extinct family of Australosphenida, native to Gondwana during the Middle Jurassic. Its defined as a clade including the most recent common ancestor of ''Henosferus'' and ''Asfaltomylos
''Asf ...
is the sister taxon to
Monotremata, with
Ausktribosphenidae
Ausktribosphenidae is an extinct family of australosphenidan mammals from the Early Cretaceous of Australia and mid Cretaceous of South America.
Classification and taxonomy
Ausktribosphenidae is closely related to monotremes and hence the two f ...
being the next sister taxa in Australosphenida.
[Averianov ''et al.'', 2014] Ausktribosphenidae includes the genera ''
Bishops
A bishop is an ordained clergy member who is entrusted with a position of authority and oversight in a religious institution.
In Christianity, bishops are normally responsible for the governance of dioceses. The role or office of bishop is ca ...
'' and ''
Ausktribosphenos
''Ausktribosphenos'' is an extinct genus of mammals from Early Cretaceous of Australia. The only recorded species, ''Ausktribosphenos nyktos'', was found on Flat Rocks, Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state ...
''.
Some 110-million-year-old monotreme fossil jaw fragments were found at
Lightning Ridge
Lightning Ridge is a small outback town in north-western New South Wales, Australia. Part of Walgett Shire, Lightning Ridge is situated near the southern border of Queensland, about east of the Castlereagh Highway. The Lightning Ridge area is ...
,
New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
. These fragments, from the species ''
Steropodon galmani
''Steropodon'' is a genus of prehistoric monotreme, or egg-laying mammal. It contains a single species, ''Steropodon galmani'', that lived about 105 to 93.3 million years ago (mya) in the Early to Late Cretaceous period. It is one of the oldest ...
'', are the oldest known monotreme fossils. Fossils from the genera ''
Kollikodon
''Kollikodon'' is an extinct species of mammal, it is usually considered to be a member of Australosphenida and closely allied with monotremes, but is alternatively suggested to be a haramiyidan. It is known only from an opalised dentary fragment ...
'', ''
Teinolophos
''Teinolophos'' is a prehistoric species of monotreme, or egg-laying mammal, from the Teinolophidae. It is known from four specimens, each consisting of a partial lower jawbone collected from the Wonthaggi Formation at Flat Rocks, Victoria (Aus ...
'', and ''
Obdurodon
''Obdurodon'' is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species ''Obdurodon insignis'', plus ''Obdurodon dicksoni'' ...
'' have also been discovered. In 1991, a fossil tooth of a 61-million-year-old platypus was found in southern
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
(since named ''Monotrematum'', though it is now considered to be an ''Obdurodon'' species). (See fossil monotremes below.)
Molecular clock
The molecular clock is a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged. The biomolecular data used for such calculations are usually nucleoti ...
and fossil dating give a wide range of dates for the split between echidnas and platypuses, with one survey putting the split at 19 to 48 million years ago,
but another putting it at 17 to 89 million years ago. All these dates are more recent than the oldest known platypus fossils, suggesting that both the short-beaked and long-beaked echidna species are derived from a platypus-like ancestor.
Systematics
History of classification
Prototheria
Originally, monotremes were classified as a subclass of mammals known as Prototheria. The names Prototheria,
Metatheria
Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well ...
and
Eutheria
Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials.
Eutherians are distinguished from noneutherians by various phenotypic tra ...
(meaning "first beasts", "changed beasts", and "true beasts", respectively) refer to the three mammalian groupings that have living representatives. Each of the three may be defined as a total
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
containing a living
crown-group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...
(respectively, the Monotremata,
Marsupialia
Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a pou ...
and
Placentalia
Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguished ...
) plus any fossil species that are more closely related to that crown-group than to any other living animals.
The threefold division of living mammals into monotremes, marsupials and placentals was already well established when
Thomas Huxley
Thomas Henry Huxley (4 May 1825 – 29 June 1895) was an English biologist and anthropologist specialising in comparative anatomy. He has become known as "Darwin's Bulldog" for his advocacy of Charles Darwin's theory of evolution.
The storie ...
proposed the names Metatheria and Eutheria to incorporate the two latter groups in 1880. Initially treated as subclasses, Metatheria and Eutheria are by convention now grouped as
infraclasses of the subclass
Theria
Theria (; Greek: , wild beast) is a subclass of mammals amongst the Theriiformes. Theria includes the eutherians (including the placental mammals) and the metatherians (including the marsupials) but excludes the egg-laying monotremes.
Ch ...
, and in more recent proposals have been demoted further (to
cohort
Cohort or cohortes may refer to:
* Cohort (educational group), a group of students working together through the same academic curriculum
* Cohort (floating point), a set of different encodings of the same numerical value
* Cohort (military unit), ...
s or even
magnorders), as
cladistic
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...
reappraisals of the relationships between living and fossil mammals have suggested that the Theria itself should be reduced in rank.
Prototheria, on the other hand, was generally recognised as a subclass until quite recently, on the basis of a hypothesis that defined the group by two supposed
synapomorphies
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...
: (1) formation of the side wall of the braincase from a bone called the anterior lamina, contrasting with the
alisphenoid
The greater wing of the sphenoid bone, or alisphenoid, is a bony process of the sphenoid bone; there is one on each side, extending from the side of the body of the sphenoid and curving upward, laterally, and backward.
Structure
The greater wi ...
in therians; and (2) a linear alignment of molar cusps, contrasting with a triangular arrangement in therians. These characters appeared to unite monotremes with a range of
Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...
fossil orders (
Morganucodon
''Morganucodon'' (" Glamorgan tooth") is an early mammaliaform genus that lived from the Late Triassic to the Middle Jurassic. It first appeared about 205 million years ago. Unlike many other early mammaliaforms, ''Morganucodon'' is well represe ...
ta,
Triconodonta,
Docodonta
Docodonta is an Order (biology), order of extinct Mammaliaformes, mammaliaforms that lived during the Mesozoic, from the Middle Jurassic to Early Cretaceous. They are distinguished from other early Mammaliaformes, mammaliaforms by their relativel ...
and
Multituberculata
Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, a ...
) in a broader clade for which the name Prototheria was retained, and of which monotremes were thought to be only the last surviving branch (Benton 2005: 300, 306).
Australosphenida hypothesis and Yinotheria
The evidence that was held to support Prototheria is now universally discounted. In the first place, the examination of embryos has revealed that the development of the braincase wall is essentially identical in therians and in 'prototherians': the anterior lamina simply fuses with the alisphenoid in therians, and therefore the 'prototherian' condition of the braincase wall is primitive for all mammals, while the therian condition can be derived from it. Additionally, the linear alignment of molar cusps is also primitive for all mammals. Therefore, neither of these states can supply a uniquely shared derived character that would support a 'prototherian' grouping of orders in contradistinction to Theria (Kemp 1983).
In a further reappraisal, the molars of embryonic and fossil monotremes (living monotreme adults are toothless) appear to demonstrate an ancestral pattern of cusps that is similar to the triangular arrangement observed in therians. Some peculiarities of this dentition support an alternative grouping of monotremes with certain recently discovered fossil forms into a proposed new clade known as the
Australosphenida
The Australosphenida are a clade of mammals, containing mammals with tribosphenic molars, known from the Jurassic to Mid-Cretaceous of Gondwana. They are thought to have acquired their tribosphenic molars independently from those of Tribosphenida ...
, and also suggest that the triangular array of cusps may have evolved independently in australosphenidans and therians (Luo ''et al.'' 2001, 2002). Australosphenida is characterized by the shared presence of a cingulum on the outer front corner of the lower molars, a short and broad talonid, a relatively low trigonid, and a triangulated last lower premolar.
The Australosphenida hypothesis remains controversial; for example, lingual cingula seem to be a presence in various non-australosphenidan mammals
[Sigogneau-Russell et al., 2001, p. 146] and some work has shown the possibility of Eutheria being the sister group to Australosphenida, without monotremes. As a result, some taxonomists (e.g. McKenna & Bell 1997) prefer to maintain the name Prototheria as a fitting contrast to the other group of living mammals, the Theria. In theory, the Prototheria is taxonomically redundant, since Monotremata is currently the only order that can still be confidently included, but its retention might be justified if new fossil evidence, or a re-examination of known fossils, enables extinct relatives of the monotremes to be identified and placed within a wider grouping.
When systematic work was performed, it was also found that Australosphenida is the sister taxon to
Shuotheriidae
Shuotheriidae is a small family of Jurassic mammals whose remains are found in China, England and possibly Russia. They have been proposed to be close relatives of Australosphenida, the group that contains living monotremes, together forming the ...
, an obscure group of Mesozoic mammals that were found in what is now
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
. had this to say regarding the Shuotheriidae, particularly ''Shuotherium'':
Yinotheria is named for this grouping.
Taxonomy
In comparison to
Metatheria
Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well ...
and
Eutheria
Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials.
Eutherians are distinguished from noneutherians by various phenotypic tra ...
, where there seems to be a better understanding on the relationships among taxa with substantial fossil evidence, Yinotheria has few fossils; mostly consisting of (with few exceptions) the jawbones and teeth. In addition, the group seems not to have been as diverse in their evolutionary history, in comparison to members of both Metatheria and Eutheria.
Future analysis and better fossil remains could affect the membership of Yinotheria as well as rearranging and revising the relationships of stem-monotremes and crowned monotremes.
* Subclass Yinotheria
Chow & Rich 1982 sensu Kielan-Jaworowska, Cifelli & Luo 2004 Gill 1872">rototheria Gill 1872** Order
Shuotherida Chow & Rich 1982 huotheridia; Shuotheria*** Family
Shuotheriidae
Shuotheriidae is a small family of Jurassic mammals whose remains are found in China, England and possibly Russia. They have been proposed to be close relatives of Australosphenida, the group that contains living monotremes, together forming the ...
Chow & Rich 1982
**** Genus ''
Pseudotribos
''Pseudotribos'' ("false chewing") is an extinct genus of mammal that lived in Northern China during the Middle Jurassic some , possibly more closely related to monotremes than to theria (placental and marsupial mammals), although other studies i ...
''
Luo, Ji & Yuan 2007
***** ''
Pseudotribos robustus''
Luo, Ji & Yuan 2007
**** Genus ''
Shuotherium
''Shuotherium'' is a fossil mammal known from Middle-Late Jurassic of the Forest Marble Formation of England,Sigogneau−Russell, D. 1998. Discovery of a Late Jurassic Chinese mammal
in the upper Bathonian of England. Comptes Rendus de l’Acad ...
''
Chow & Rich 1982
***** ''
Shuotherium dongi
''Shuotherium'' is a fossil mammal known from Middle-Late Jurassic of the Forest Marble Formation of England,Sigogneau−Russell, D. 1998. Discovery of a Late Jurassic Chinese mammal
in the upper Bathonian of England. Comptes Rendus de l’Acad ...
''
Chow & Rich 1982
***** ''
Shuotherium shilongi''
Wang et al. 1998
** Infraclass
Australosphenida
The Australosphenida are a clade of mammals, containing mammals with tribosphenic molars, known from the Jurassic to Mid-Cretaceous of Gondwana. They are thought to have acquired their tribosphenic molars independently from those of Tribosphenida ...
Luo, Cifelli & Kielan-Jaworowska 2001 sensu Kielan-Jaworowska, Cifelli & Luo 2004
*** Order
Ausktribosphenida
Ausktribosphenidae is an extinct family of Australosphenida, australosphenidan mammals from the Early Cretaceous of Australia and mid Cretaceous of South America.
Classification and taxonomy
Ausktribosphenidae is closely related to monotremes an ...
Luo, Cifelli & Kielan-Jaworowska 2001
**** Family
Ausktribosphenidae
Ausktribosphenidae is an extinct family of australosphenidan mammals from the Early Cretaceous of Australia and mid Cretaceous of South America.
Classification and taxonomy
Ausktribosphenidae is closely related to monotremes and hence the two f ...
Rich et al. 1997
***** Genus ''
Bishops
A bishop is an ordained clergy member who is entrusted with a position of authority and oversight in a religious institution.
In Christianity, bishops are normally responsible for the governance of dioceses. The role or office of bishop is ca ...
''
Rich et al. 2001
****** ''
Bishops whitmorei
''Bishops'' is an extinct genus of mammals from Early Cretaceous of Australia. The only recorded species, ''Bishops whitmorei'', was found on Flat Rocks, Wonthaggi Formation, Victoria. The genus was named in honour of Dr Barry Bishop, the forme ...
''
Rich et al. 2001
***** Genus ''
Ausktribosphenos
''Ausktribosphenos'' is an extinct genus of mammals from Early Cretaceous of Australia. The only recorded species, ''Ausktribosphenos nyktos'', was found on Flat Rocks, Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state ...
''
Rich et al. 1997
****** ''
Ausktribosphenos nyktos
''Ausktribosphenos'' is an extinct genus of mammals from Early Cretaceous of Australia. The only recorded species, ''Ausktribosphenos nyktos'', was found on Flat Rocks, Victoria
Victoria most commonly refers to:
* Victoria (Australia), a st ...
''
Rich et al. 1997
*** Order
Henosferida Averianov & Lopatin 2011
**** Family
Henosferidae
Henosferidae (also spelled "Henospheridae") is an extinct family of Australosphenida, native to Gondwana during the Middle Jurassic. Its defined as a clade including the most recent common ancestor of ''Henosferus'' and ''Asfaltomylos
''Asf ...
Rougier et al. 2007
***** Genus ''
Ambondro''
[Woodburne, 2003]
****** ''
Ambondro mahabo
''Ambondro mahabo'' is a mammal from the Middle Jurassic (Bathonian) Isalo III Formation (about 167 million years ago) of Madagascar. The only described species of the genus ''Ambondro'', it is known from a fragmentary lower jaw with three teeth ...
''
Flynn et al. 1999
***** Genus ''
Asfaltomylos
''Asfaltomylos'' is an extinct genus of the primitive mammal subclass Australosphenida from the Jurassic of Argentina. The type and only species is ''Asfaltomylos patagonicus'', recovered from and named after the Cañadón Asfalto Formation, Caà ...
''
Rauhut et al. 2002
****** ''
Asfaltomylos patagonicus''
Rauhut et al. 2002
***** Genus ''
Henosferus
''Henosferus'' is an extinct genus of australosphenidan mammal from Lower Jurassic of Argentina. The only recorded species, ''Henosferus molus'', was found in the Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Chubut Province
Chu ...
''
Rougier et al. 2007
****** ''
Henosferus molus''
Rougier et al. 2007
*** Order
Monotremata Bonaparte 1837 sensu Luo, Cifelli & Kielan-Jaworowska 2001
**** Family
Incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
***** Genus ''
Kryoryctes
''Kryoryctes'' is a genus of prehistoric monotreme mammal from the Early Cretaceous (Albian) Eumeralla Formation of Victoria, Australia from the Otway Group of Dinosaur Cove. It is known only from a partial right humerus, estimated at 106 millio ...
''
Pridmore et al. 2005 (either a stem-monotreme
or junior synonym of ''
Steropodon
''Steropodon'' is a genus of prehistoric monotreme, or egg-laying mammal. It contains a single species, ''Steropodon galmani'', that lived about 105 to 93.3 million years ago (mya) in the Early to Late Cretaceous period. It is one of the oldest ...
''
)
****** ''
Kryoryctes cadburyi''
Pridmore et al. 2005
**** Family
Tachyglossidae Gill 1872 Echidnidae_
Burnett_1830.html" ;"title="Echidnidae.html" ;"title="Echidnidae">Echidnidae
Burnett 1830">Echidnidae.html" ;"title="Echidnidae">Echidnidae
Burnett 1830(echidnas, spiny anteaters)
***** Genus ''Megalibgwilia''
Griffiths, Wells & Barrie 1991 (subjective synonym or subgenus of ''Zaglossus'')
****** ''Megalibgwilia robusta''
(Dun 1895) (subjective synonym of ''Zaglossus robustus'')
****** ''
Megalibgwilia ramsayi
''Megalibgwilia'' is a genus of echidna known only from Australian fossils that incorporates the oldest-known echidna species. The genus ranged from the Miocene until the late Pleistocene, becoming extinct about 50,000 years ago. ''Megalibgwilia ...
''
(Owen 1884) (senior synonym of ''
Megalibgwilia owenii''
[Ashwell, 2013])
***** Genus ''
Zaglossus
The long-beaked echidnas (genus ''Zaglossus'') make up one of the two extant genus, genera of echidnas, spiny monotremes that live in New Guinea; the other being the short-beaked echidna. There are three living species and one extinct species in ...
''
Gill 1877 'Proechidna''_
Gervais_1877;_''Acanthoglossus.html" ;"title="Proechidna.html" ;"title="'Proechidna">'Proechidna''
Gervais 1877; ''Acanthoglossus">Proechidna.html" ;"title="'Proechidna">'Proechidna''
Gervais 1877; ''Acanthoglossus''
Gervais 1877; ''Bruynia''
Dubois 1882; ''Bruijia''
Thomas 1883; ''Prozaglossus''
Kerbert 1913] (Long-beaked Echidnas)
****** ''Murrayglossus''
Glauert 1914 (Hackett's Giant Echidna) (might belong to a new genus
)
****** ''
Zaglossus bruijni
The western long-beaked echidna (''Zaglossus bruijnii'') is one of the four extant echidnas and one of three species of ''Zaglossus'' that occurs in New Guinea. Originally described as ''Tachyglossus bruijnii'', this is the type species of ''Zag ...
''
(Peters & Doria 1876) (Western Long-beaked/Bruinj's/Brown False Echidna)
****** ''
Zaglossus attenboroughii''
Flannery & Groves 1998 (Attenborough's/Sir David's/Cyclops Long-beaked Echidna)
****** ''
Zaglossus bartoni
The eastern long-beaked echidna (''Zaglossus bartoni''), also known as Barton's long-beaked echidna, is one of three species from the genus '' Zaglossus'' to occur in New Guinea. It is found mainly in the eastern half at elevations between .
Des ...
''
Thomas 1907 (Eastern/Barton's Long-beaked/Grey False Echidna)
***** Genus ''
Tachyglossus
The short-beaked echidna (''Tachyglossus aculeatus''), also called the short-nosed echidna, is one of four living species of echidna and the only member of the genus ''Tachyglossus''. It is covered in fur and spines and has a distinctive snout ...
''
Illiger 1811 'Acanthonotus''_
Goldfuss_1809;_''Echidna.html" ;"title="Acanthonotus.html" ;"title="'Acanthonotus">'Acanthonotus''
Goldfuss 1809; ''Echidna">Acanthonotus.html" ;"title="'Acanthonotus">'Acanthonotus''
Goldfuss 1809; ''Echidna''
Cuvier 1798; ''Echinopus''
Fischer de Waldheim 1814; ''Syphomia''
Rafinesque 1815]
****** ''Tachyglossus aculeatus''
(Shaw 1792) Illiger 1811 (short-beaked Echidna)
**** Family
Kollikodontidae Flannery et al. 1995
***** Genus ''
Kollikodon
''Kollikodon'' is an extinct species of mammal, it is usually considered to be a member of Australosphenida and closely allied with monotremes, but is alternatively suggested to be a haramiyidan. It is known only from an opalised dentary fragment ...
''
Flannery et al. 1995 (might be a
mammaliform
Mammaliaformes ("mammalian forms") is a clade that contains the crown group mammals and their closest extinct relatives; the group radiated from earlier probainognathian cynodonts. It is defined as the clade originating from the most recen ...
of uncertain placement
)
****** ''
Kollikodon ritchiei
''Kollikodon'' is an extinct species of mammal, it is usually considered to be a member of Australosphenida and closely allied with monotremes, but is alternatively suggested to be a haramiyidan. It is known only from an opalised dentary fragment ...
''
Flannery et al. 1995
**** Family
Steropodontidae Archer et al. 1985
***** Genus ''
Teinolophos
''Teinolophos'' is a prehistoric species of monotreme, or egg-laying mammal, from the Teinolophidae. It is known from four specimens, each consisting of a partial lower jawbone collected from the Wonthaggi Formation at Flat Rocks, Victoria (Aus ...
''
Rich et al. 1999 (might be a basal monotreme or a stem-monotreme
)
****** ''
Teinolophos trusleri
''Teinolophos'' is a prehistoric species of monotreme, or egg-laying mammal, from the Teinolophidae. It is known from four specimens, each consisting of a partial lower jawbone collected from the Wonthaggi Formation at Flat Rocks, Victoria (Aus ...
''
Rich et al. 1999
***** Genus ''
Steropodon
''Steropodon'' is a genus of prehistoric monotreme, or egg-laying mammal. It contains a single species, ''Steropodon galmani'', that lived about 105 to 93.3 million years ago (mya) in the Early to Late Cretaceous period. It is one of the oldest ...
''
Archer et al. 1985
****** ''
Steropodon galmani
''Steropodon'' is a genus of prehistoric monotreme, or egg-laying mammal. It contains a single species, ''Steropodon galmani'', that lived about 105 to 93.3 million years ago (mya) in the Early to Late Cretaceous period. It is one of the oldest ...
''
Archer et al. 1985
**** Family
Ornithorhynchidae
The Ornithorhynchidae are one of the two extant families in the order Monotremata, and contain the platypus and its extinct relatives. The other family is the Tachyglossidae, or echidnas. Within the Ornithorhynchidae are the genera '' Monotrem ...
Gray 1825
***** Genus ''
Monotrematum
''Monotrematum sudamericanum'' is an extinct monotreme species from the Paleocene (Peligran) Salamanca Formation in Patagonia, Argentina. It is the only monotreme found outside Oceania.
Taxonomy
A species described in 1992 and assigned to a new ...
''
Pascual et al. 1992 (here considered to be a basal ornithorhynchid;
others subjective synonym of ''Obdurodon'')
****** ''
Monotrematum sudamericanum''
Pascual et al. 1992
***** Genus ''
Obdurodon
''Obdurodon'' is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species ''Obdurodon insignis'', plus ''Obdurodon dicksoni'' ...
''
Woodburne & Tedford 1975
****** ''
Obdurodon insignis
''Obdurodon'' is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species ''Obdurodon insignis'', plus ''Obdurodon dicksoni'' ...
''
Woodburne & Tedford 1975
****** ''
Obdurodon tharalkooschild
''Obdurodon'' is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species ''Obdurodon insignis'', plus ''Obdurodon dicksoni'' a ...
''
Pian, Archer & Hand 2013
****** ''
Obdurodon dicksoni
''Obdurodon'' is a genus of extinct platypus-like Australian monotreme which lived from the Late Oligocene to the Late Miocene. Three species have been described in the genus, the type species ''Obdurodon insignis'', plus ''Obdurodon dicksoni'' ...
''
Archer et al. 1992 (Riversleigh platypus)
***** Genus ''
Ornithorhynchus
The platypus (''Ornithorhynchus anatinus''), sometimes referred to as the duck-billed platypus, is a semiaquatic, egg-laying mammal endemic to eastern Australia, including Tasmania. The platypus is the sole living representative or monotyp ...
''
Blumenbach 1800 'Dermipus''_
Wiedermann_1800;_''Platypus.html" ;"title="Dermipus.html" ;"title="'Dermipus">'Dermipus''
Wiedermann 1800; ''Platypus">Dermipus.html" ;"title="'Dermipus">'Dermipus''
Wiedermann 1800; ''Platypus''
Shaw 1799 non Herbst 1793]
****** ''Ornithorhynchus anatinus''
(Shaw 1799) Blumenbach 1800 (platypus)
Phylogeny
Below is a simplified tree on Averianov ''et al.'', 2014
after Woodburn, 2003
and Ashwell, 2013
References
Bibliography
*
*
*
*
*
*
* McKenna, Malcolm C., and Susan K. Bell. 1997. ''Classification of Mammals Above the Species Level''. New York: Columbia University Press.
*
External links
*
*
{{Taxonbar, from=Q21448022
Mammal taxonomy
Vertebrate subclasses
Extant Late Triassic first appearances
Taxa named by Zhou Mingzhen
Taxa named by Tom Rich