Wheeler Shale
Encyclopedia
The Wheeler Shale is a Cambrian (c.
507 Ma) fossil locality world famous
for prolific agnostid and Elrathia kingii
trilobite remains (even though many areas are barren of fossils)
and represents a Konzentrat-Lagerstätten
. Varied soft bodied organisms are locally preserved, a fauna (including Naraoia
, Wiwaxia
and Hallucigenia
) and preservation style (carbonaceous film
) normally associated with the more famous Burgess Shale
. As such, the Wheeler Shale also represents a Konservat-Lagerstätten
.
Together with the Marjum Formation
and lower Weeks Formation, the Wheeler Shale forms 490 to 610 m (1,600 to 2,000 ft) of limestone and shale exposed in one of the thickest, most fossiliferous and best exposed sequences of Middle Cambrian rocks in North America.
At the type locality of Wheeler Amphitheater, House Range, Millard County, western Utah, the Wheeler Shale consists of a heterogeneous succession of highly calcareous shale, shaley limestone, mudstone and thin, flaggy limestone. The Wheeler Formation (although the Marjum & Weeks Formations are missing) extends into the Drum Range, northwest of the House Range where similar fossils and preservation are found.
and uppermost-Middle Cambrian Bolaspidella trilobite zone
s (See House Range
) for full stratigraphy).
(Note: the preservation of hard bodied trilobite remains and soft bodied animals seems to be mutually exclusive within particular horizons.)
Arachnomorpha
Mollusca
Priapulida
Circa
Circa , usually abbreviated c. or ca. , means "approximately" in the English language, usually referring to a date...
507 Ma) fossil locality world famous
for prolific agnostid and Elrathia kingii
Elrathia kingii
Elrathia is a genus of trilobite species that lived during the Middle Cambrian. E. kingii is one of the most common trilobite fossils in the USAlocally found in extremely high concentrations within the Wheeler Formation in the U.S. state of Utah....
trilobite remains (even though many areas are barren of fossils)
and represents a Konzentrat-Lagerstätten
Lagerstätte
A Lagerstätte is a sedimentary deposit that exhibits extraordinary fossil richness or completeness.Palaeontologists distinguish two kinds....
. Varied soft bodied organisms are locally preserved, a fauna (including Naraoia
Naraoia
Naraoia is a genus of trilobites found in Cambrian strata of the Burgess Shale and the Maotianshan shales Lagerstätte. They were flattened, oval-shaped animals, with an uncalcified shield that was divided into two regions, a smaller region covering the head, and a larger section covering the...
, Wiwaxia
Wiwaxia
Wiwaxia is a genus of soft-bodied, scale-covered animals known from Burgess shale type Lagerstätte dating from the upper Lower Cambrian to Middle Cambrian. The organisms are mainly known from dispersed sclerites; articulated specimens, where found, range from to a little over 50.8 millimeters in...
and Hallucigenia
Hallucigenia
Hallucigenia is an extinct genus of animal found as fossils in the Middle Cambrian-aged Burgess Shale formation of British Columbia, Canada, represented by the species H. sparsa, and in the Lower Cambrian Maotianshan shale of China, represented by the species H. fortis...
) and preservation style (carbonaceous film
Burgess shale type preservation
The Burgess Shale of British Columbia is famous for its exceptional preservation of mid-Cambrian organisms. Around 40 other sites have been discovered of a similar age, with soft tissues preserved in a similar, though not identical, fashion...
) normally associated with the more famous Burgess Shale
Burgess Shale
The Burgess Shale Formation, located in the Canadian Rockies of British Columbia, is one of the world's most celebrated fossil fields, and the best of its kind. It is famous for the exceptional preservation of the soft parts of its fossils...
. As such, the Wheeler Shale also represents a Konservat-Lagerstätten
Lagerstätte
A Lagerstätte is a sedimentary deposit that exhibits extraordinary fossil richness or completeness.Palaeontologists distinguish two kinds....
.
Together with the Marjum Formation
Marjum formation
The Marjum formation is a Cambrian geological formation that overlies the Wheeler Shale in the House Range, Utah. It is known for its occasional preservation of soft-bodied tissue, and is slightly younger than the Burgess Shale, falling in the Ptychagnostus praecurrens trilobite zone....
and lower Weeks Formation, the Wheeler Shale forms 490 to 610 m (1,600 to 2,000 ft) of limestone and shale exposed in one of the thickest, most fossiliferous and best exposed sequences of Middle Cambrian rocks in North America.
At the type locality of Wheeler Amphitheater, House Range, Millard County, western Utah, the Wheeler Shale consists of a heterogeneous succession of highly calcareous shale, shaley limestone, mudstone and thin, flaggy limestone. The Wheeler Formation (although the Marjum & Weeks Formations are missing) extends into the Drum Range, northwest of the House Range where similar fossils and preservation are found.
Taphonomy & Sedimentology
Detailed work recognises a number of ~10 m thick lagerstätten sequences in the formation, each of which formed at a sea-level high stand in deep water. The lagerstätte were deposited by turbitides and mudslides onto an oxygenated sea floor.Stratigraphy
The Wheeler Shale spans the Ptychagnostus atavusPtychagnostus
Ptychagnostus is an extinct genus of blind trilobite that lived during the Cambrian period, part of the order Agnostida. Ptychagnostidae generally do not exceed ten millimetres in length. Their remains are sometimes found in the otherwise empty tubes of the polychaete worm Selkirkia. It probably...
and uppermost-Middle Cambrian Bolaspidella trilobite zone
Trilobite zone
Trilobites are used as index fossils to subdivide the Cambrian period. Assemblages of trilobites define trilobite zones. The Olenellus zone has traditionally marked the top of the Lower Cambrian, and is followed by the Eokochaspis zone....
s (See House Range
House Range
The House Range is a north-south trending mountain range in west-central Utah. It is famous for Notch Peak, one of the tallest limestone cliffs in the world, and a fossil Lagerstätte of Cambrian age, which has an array of Burgess Shale type fauna, including Elrathia kingii, a trilobite that is...
) for full stratigraphy).
Fauna
Incomplete list of the fauna of the Wheeler Shale:(Note: the preservation of hard bodied trilobite remains and soft bodied animals seems to be mutually exclusive within particular horizons.)
Protista
- MargaretiaMargaretiaMargaretia is a frondose organism known from the middle Cambrian Burgess shale. Its fronds reached about 10 cm in length and are peppered with a range of length-parallel oval holes. Its original interpretation as a green alga is not secure; it also resembles some alcyonarian corals, but a...
dorus - algaeAlgaeAlgae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
? or possibly alcyonarianAlcyonarianThe Alcyonarian corals are organisms resembling the octocorals . This individual polyps formed colonies and bore sclerites. The Burgess shale organism Margaretia dorus resembles an Alcyonarian, according to C.D. Walcott , and was reclassified as green algae closely resembling modern Caulerpa by...
coralCoralCorals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of... - MarpoliaMarpoliaMarpolia has been interpreted as a cyanobacterium, but also resembles the modern cladophoran green algae. It is known from the Middle Cambrian Burgess shale and Early Cambrian deposits from the Czech Republic. It comprises a dense mass of entangled, twisted filaments. It may have been...
spissa - cyanobacteria or green algaeGreen algaeThe green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic... - MoraniaMoraniaMorania is a genus of cyanobacterium preserved as carbonaceous films in the Middle Cambrian Burgess Shale. it is present throughout the shale; 2580 specimens of Morania are known from the Greater Phyllopod bed, where they comprise 4.90% of the community. It is filamentous, forms sheets, and...
fragmenta - cyanobacteria - YuknessiaYuknessiaYuknessia is a very putative green alga known from three Burgess shale specimens, and some from the Chengjiang and Wheeler shale. Long, unbranched fronds emerge from a central holdfast-like body covered in small conical plates...
simplex - green algae?
Arthropoda
- Branchiocaris pretiosa - crustaceanCrustaceanCrustaceans 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...
- Branchiocaris sp.
- Cambropodus gracilis - uniramiaUniramiaS. M. Manton's polyphyletic Arthropod hypothesis with Uniramia as one of three Phyla.Uniramia is a group within the arthropods. In the past this group included the Onychophora, which are now considered a separate category. The group is currently used in a narrower sense.Uniramia is one of three...
n - CanadaspisCanadaspisCanadaspis was a Cambrian genus of crustacean or euarthropod, a benthic feeder that moved mainly by walking and possibly used its biramous appendages to stir mud in search of food...
perfecta - crustacean or euarthropod - Dicerocaris opisthoeces
- Emeraldella brocki - chelicerateChelicerataThe subphylum Chelicerata constitutes one of the major subdivisions of the phylum Arthropoda, and includes horseshoe crabs, scorpions, spiders and mites...
? - Pahvantia hastata - local genusGenusIn 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...
named after the Pahvant - PerspicarisPerspicarisPerspicaris is a fossil arthropod from the Cambrian period. It was long and bivalved. The valves, encasing the thorax, were joined together by a dorsal hinge.It is difficult to establish the lifestyle of Perspicaris...
dilatus - Proboscicaris agnosta
- Pseudoarctolepis sharpie - phyllocarida
- TuzoiaTuzoiaTuzoia is a large bivalved arthropod known from the Burgess Shale, British Columbia, and Kaili . This arthropod reached lengths of 180 mm long. There are currently 7 valid species recognized....
? peterseni - thylacocephalaThylacocephalaThe Thylacocephala are a unique group of extinct arthropods, with possible crustacean affinities. As a class they have a short research history, having been erected in the early 1980s. They typically possess a large, laterally flattened carapace that encompasses the entire body...
n
ArachnomorphaArachnomorphaArachnomorpha Lameere 1890 is a subdivision or clade of Arthropoda, comprising the monophyletic group formed by the trilobites, other great appendage arthropods and trilobite-like families , and a diverse sister clade including the chelicerates...
- AlalcomenaeusAlalcomenaeusAlalcomenaeus is one of the most widespread and longest surviving arthropod genera of the Early and Middle Cambrian. Known from over 300 specimens in the Burgess shale, and the Chengjiang, it bears great similarity to the opabiniids.-Morphology:...
cambrius - megacheiraMegacheiraMegacheira is an extinct class of predatory euarthropods that possessed a pair of short enlarged appendages . They were found in marine environments throughout the world from the lower to middle Cambrian, and were important components of several faunas, including the Burgess and Maotianshan...
n; opabinidOpabinidOpabinids are organisms resembling the Burgess shale creature Opabinia, and by inference related to it. The status of the group and its constituent members are very much up in the air, as are the group's relationships with other organisms: some posit a close relationship with the...
or alalcomenaeid - Dicranocaris guntherorum - megacheiran; opabinid or alalcomenaeid
- unnamed 'Molli Sonia symmetrica'
- SidneyiaSidneyiaSidneyia is an extinct arthropod known from fossils found in the Cambrian-age Burgess Shale formation of British Columbia. -General description:...
inexpectans - merostomoidMerostomoideaMerostomoidea is a paraphyletic group of fossil arthropods. They have been described as a transitional form between trilobites and true chelicerates.-Sources:http://www.palaeos.com/Invertebrates/Arthropods/Arachnomorpha.html#Merostomoidea...
Trilobita
- NaraoiaNaraoiaNaraoia is a genus of trilobites found in Cambrian strata of the Burgess Shale and the Maotianshan shales Lagerstätte. They were flattened, oval-shaped animals, with an uncalcified shield that was divided into two regions, a smaller region covering the head, and a larger section covering the...
compacta - naraoiidNaraoiidaeThe Naraoiidae is a family of soft-shelled trilobite-like arthropods that are known only from the early and middle Cambrian -- primarily from the Burgess Shale of British Columbia and the Maotianshan Shale of China....
nectaspidNectaspidaThe Nectaspida is an extinct order of soft-bodied arthropods proposed by Raymond in 1920; its taxonomic status is uncertain. Specimens are known from the early Cambrian to the upper Silurian periods. Whittington placed the order in the Trilobita... - Hypagnostus parvifrons - agnostid
- PeronopsisPeronopsisPeronopsis is a genus of trilobite from the Cambrian. Its remains have been found in Asia, Australia, Europe, and North America.Peronopsis is represented by the following species in the Wheeler Shale of Utah: P. bidens, P. fallax, P. gaspensis, P. intermedius, P. interstrictus , P. montis, and P....
amplaxis - peronopsid agnostid - Peronopsis bidens
- Peronopsis fallax
- Peronopsis gaspensis
- Peronopsis intermedius
- Peronopsis interstrictus
- Peronopsis montis
- Peronopsis segmentis
- PtychagnostusPtychagnostusPtychagnostus is an extinct genus of blind trilobite that lived during the Cambrian period, part of the order Agnostida. Ptychagnostidae generally do not exceed ten millimetres in length. Their remains are sometimes found in the otherwise empty tubes of the polychaete worm Selkirkia. It probably...
atavus (= Acidusus atavus) - ptychagnostid agnostid - Ptychagnostus germanus
- Ptychagnostus gibbus
- Ptychagnostus intermedius
- Ptychagnostus michaeli
- Ptychagnostus occultatus
- Ptychagnostus seminula
- Glyphaspis concavus - asaphidAsaphidaAsaphida is a large, morphologically diverse order of trilobite found in strata dated from the Middle Cambrian to the Silurian. The order contains six superfamilies , but no suborders...
- BathyuriscusBathyuriscusBathyuriscus is an extinct genus of Cambrian trilobite. It was a nektobenthic predatory carnivore. Specimens have been found in the Marjumian of the USA and in the Middle Cambrian of Australia, Canada , Greenland, Mexico, and the USA...
fimbriatus - dolichometopidDolichometopidaeDolichometopidae is a family of trilobites that lived in the Cambrian, from the lower Botomian to the Dresbachian. It contains the following genera:*Aegunaspis*Amphoton*Anoria*Asperocare*Athabaskia*Athabaskiella*Atypicus...
corynexochidCorynexochidaCorynexochida is an order of trilobite that lived from the Lower Cambrian to the Middle Devonian. Like many of the other trilobite orders, Corynexochida contains many species with widespread characteristics.... - Bathyuriscus sp.
- KooteniaKooteniaKootenia is a genus of trilobites of the family Dorypygidae. Its major characteristics are that of the closely related Olenoides, including medium size, a large glabella, and a medium-sized pygidium, but also a lack of the strong interpleural furrows on the pygidium that Olenoides...
sp. - dorypygid corynexochid, perhaps a synonym of Olenoides - OlenoidesOlenoidesOlenoides was a trilobite from the Cambrian period. Its fossils are found well-preserved in the Burgess Shale in Canada. It grew up to 10 cm long....
expansus - dorypygid corynexochid - Olenoides nevadensis
- Olenoides serratus
- Tonkinella breviceps
- ZacanthoidesZacanthoidesZacanthoides is an extinct Cambrian genus of trilobite. It was a nektobenthic predatory carnivore. Its remains have been found in Canada , Greenland, Mexico, and the USA...
divergens - zacanthoidid corynexochid - Zacanthoides sp.
- Altiocculus harrisi - ptychopariidPtychopariidaPtychopariida is a large, heterogeneous order of trilobite containing some of the most primitive species known. Many date to the Early Cambrian Period, but the order was extant through the Late Ordovician...
(specific name may be confused with Alokistocare) - Alokistocare harrisi - alokistocaridAlokistocaridaeAlokistocaridae is a family of extinct trilobites. Alokistocarids were particle feeders and left small furrows with are occasionally preserved. Their remains are found worldwide....
ptychopariid - AsaphiscusAsaphiscusAsaphiscus is a genus of trilobite that lived in the Cambrian. Its remains have been found in Australia and North America, especially in Utah.-External links:* in the Paleobiology Database...
wheeleri - ptychopariid; second-most common species in the formation - Bathyocos housensis - ptychopariid
- Bolaspidella drumensis
- Bolaspidella housensis
- Bolaspidella sp.
- Bolaspidella wellsvillensis
- Brachyaspidion microps
- Brachyaspidion sulcatum
- Cedaria minor - known from the Warrior FormationWarrior FormationThe Cambrian Warrior Formation is a mapped limestone bedrock unit in Pennsylvania.-Description:The Warrior Formation is described by Berg and others as gray, thin- to medium-bedded, fossiliferous, cyclic limestone bearing stromatolites, interbedded with shale, siltstone, and sandstone.-Fossils:*...
- Elrathia kingii - alokistocarid ptychopariid
- Elrathia sp.
- Elrathina wheeleri = Ptychoparella wheeleri? - ptychopariid
- Jenkinsonia varga
- Modocia brevispina
- Modocia laevinucha
- Modocia typicalis
- Ptychoparella sp. - ptychopariid
- Ptychoparella wheeleri
- Spencella sp. - ptychopariid
MolluscaMolluscaThe Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
- Pelagiella sp. - pelagiellidPelagiellidaePelagiellidae is an extinct family of paleozoic molluscs.- 2005 taxonomy :The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005 categorizes Pelagiellidae in the superfamilia Pelagielloidea within the...
helcionelloidHelcionelloidaHelcionelloida is the name given to an extinct group of ancient molluscs . These are the oldest known conchiferan molluscs, that is, they had a mineralised shell. Some members of this class were mistaken for Monoplacophorans. The class was erected by Peel in 1991.-Anatomy:These animals were...
Echinodermata
- Castericystis sprinklei - carpoid
- Castericystis sp.
- CothurnocystisCothurnocystisCothurnocystis along with all of its relatives in Stylophora, are enigmatic organisms whose relationship with other organisms, namely the Echinodermata and the Chordata, are in a state of flux. It was boot-shaped and has been suspected to have contained a primitive notochord...
sp. - stylophoraStylophoraThe stylophorans are an extinct, possibly polyphyletic group allied to the echinoderms, comprising the cornutes and mitrates. It is synonymous with the subphylum Calcichordata....
n - Ctenocystis sp. - ctenocystoid
- GogiaGogiaGogia is a primitive genus of the Class Eocrinoidea, belonging to the early echinoderm Subphylum Blastozoa , dated from the Cambrian.G...
spiralis - eocrinoid - Eocrinoid holdfasts believed to belong to Gogia spiralis; may belong to other species
Porifera
- ChoiaChoiaChoia is a fossil demosponge dating to the Cambrian and Lower Ordovician periods. It was unusual because it was not attached to the sea bed, and radiated spines from the edge of its flattish, conical body, producing an appearance not unlike that of the peak of a big top, with guy lines...
carteri - choiid monaxonid demospongeDemospongeThe Demospongiae are the largest class in the phylum Porifera. Their "skeletons" are made of spicules consisting of fibers of the protein spongin, the mineral silica, or both. Where spicules of silica are present, they have a different shape from those in the otherwise similar glass sponges... - Choia utahensis
- CrumillospongiaCrumillospongiaCrumillospongia is a genus of middle Cambrian sponge known from the Burgess Shale and other localities from the Lower and Middle Cambrian. Its name is a reflection of its similarity to a small leathery money purse, or Crumilla . That is, it has a saclike shape, and its wall has holes of two sizes,...
sp. - hazeliidHazeliidaeThe Hazeliidae are a family of spicular Cambrian demosponges known from the Burgess Shale, the Marjum Formation of Utah, and possibly Chengjiang. It was described by Charles Walcott in 1920....
monaxonid demosponge - DiagonellaDiagonellaDiagonella is a genus of sponge known from the Middle Cambrian Burgess Shale....
sp.
PriapulidaPriapulidaPriapulida is a phylum of marine worms. They are named for their extensible spiny proboscis, which, in some species, may have a shape like that of a human penis...
- SelkirkiaSelkirkiaSelkirkia is a genus of predatory priapulid worm known from the Middle Cambrian Burgess Shale. In the Burgess Shale, 20% of the tapering, organic-walled tubes are preserved with the worm inside them, whereas the other 80% are empty...
sp. - archaeopriapulidArchaeopriapulidaThe archaeopriapulida are a group of priapulid-like worms known from Cambrian lagerstatte. The group is ancestral but very similar to the modern Priapulids. It is unclear whether it is mono- or polyphyletic... - "Selkirkia willoughbyi" (Note: S. columbia is the only recognized species)
Unclassified
- AysheaiaAysheaiaAysheaia was a genus of soft-bodied, caterpillar-shaped organisms average body length of 1–6 cm. The genus name commemorates a mountain peak named "Ayesha" due north of the Wapta Glacier. This peak was originally named Aysha in the 1904 maps of the region, and was re-named Ayesha after the heroine...
prolata - xenusiidXenusiidXenusiids are a group of lobopods resembling Xenusion. They have relatively large, annulated, cylindrical body. Their lobopod legs have tubercles at their bases. Some have large frontal appendages, although these may represent taphonomic artefacts. Their mouth is terminal or subterminal, and they...
lobopod or onychophoran - HallucigeniaHallucigeniaHallucigenia is an extinct genus of animal found as fossils in the Middle Cambrian-aged Burgess Shale formation of British Columbia, Canada, represented by the species H. sparsa, and in the Lower Cambrian Maotianshan shale of China, represented by the species H. fortis...
sparsa - ?xenusiid lobopod or onychophoran - ChancelloriaChancelloriaChancelloria is a genus of early animal known from the Middle Cambrian Burgess Shale, the Comley limestone, the Wheeler Shale,, the Bright Angel Shale and elsewhere. It was first described in 1920 by Charles Doolittle Walcott, who regarded them as one of the most primitive groups of sponges...
pentacta - chancelloriidChancelloriidaeThe Chancelloriids are an extinct family of animal common in sediments from the Early Cambrian to the early Late Cambrian. Many of these fossils consists only of spines and other fragments, and it is not certain that they belong to the same type of organism...
coeloscleritophoran, perhaps a sponge? - AnomalocarisAnomalocarisAnomalocaris is an extinct genus of anomalocaridid, which are, in turn, thought to be closely related to the arthropods. The first fossils of Anomalocaris were discovered in the Ogygopsis Shale by Joseph Frederick Whiteaves, with more examples found by Charles Doolittle Walcott in the famed...
sp. - anomalocaridid, perhaps a stem-group of the arthropodArthropodAn 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...
s - EldoniaEldoniaEldonia is a soft-bodied animal of unknown affinity, best known from the Fossil Ridge outcrops of the Burgess Shale, particularly in the 'Great Eldonia layer' in the Walcott Quarry...
sp. - eldoniid paropsonemidParopsonemidThe paropsonemids are problematic fossils known from the Ordovician to Devonian periods, which may be related to the Cambrian eldoniids. They are typified by the Chengjiang genus Paropsonema....
cambroernidCambroernidThe Cambroernids are a clade containing the eldoniids and Herpetogaster-like forms.... - Hylolithellus sp. - annelidAnnelidThe annelids , formally called Annelida , are a large phylum of segmented worms, with over 17,000 modern species including ragworms, earthworms and leeches...
? - WiwaxiaWiwaxiaWiwaxia is a genus of soft-bodied, scale-covered animals known from Burgess shale type Lagerstätte dating from the upper Lower Cambrian to Middle Cambrian. The organisms are mainly known from dispersed sclerites; articulated specimens, where found, range from to a little over 50.8 millimeters in...
corrugata - halwaxiidHalwaxiidaHalwaxiida or halwaxiids is a proposed clade loosely uniting scale-bearing Cambrian animals, which may lie in the stem group to molluscs or lophotrochozoa. Some palaeontologists question the validity of the Halwaxiida clade.-Definition and members:...
? lophotrochozoaLophotrochozoaThe Lophotrochozoa are a major grouping of protostome animals. The taxon was discovered based on molecular data. Molecular evidence such as a result of studies of the evolution of small-subunit ribosomal RNA supports the monophyly of the phyla listed in the infobox shown at right.-Terminology:The...
n