order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
class
Class or The Class may refer to:
Common uses not otherwise categorized
* Class (biology), a taxonomic rank
* Class (knowledge representation), a collection of individuals or objects
* Class (philosophy), an analytical concept used differentl ...
Lingulata
Lingulata is a class of brachiopods, among the oldest of all brachiopods having existed since the Cambrian period (). They are also among the most morphologically conservative of the brachiopods, having lasted from their earliest appearance to the ...
. The order is equivalent to the sole superfamily Siphonotretoidea, itself containing the sole family Siphonotretidae. They were most abundant in the
Late Cambrian
Late may refer to:
* LATE, an acronym which could stand for:
** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia
** Local-authority trading enterprise, a New Zealand business law
** Local average treatment effect, ...
Furongian
The Furongian is the fourth and final epoch and series of the Cambrian. It lasted from to million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocian Stage. It is subdivided into three sta ...
to
Floian
The Floian is the second stage of the Ordovician Period. It succeeds the Tremadocian with which it forms the Lower Ordovician epoch. It precedes the Dapingian Stage of the Middle Ordovician. The Floian extended from to million years ago. The lowe ...
), and were traditionally considered to have gone extinct in the Upper Ordovician ( Ashgill). However, they may have been present as early as
Cambrian Stage 4
Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission on ...
, and as late as the
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...
( Ludlow). Siphonotretoids were originally placed as a superfamily of
Acrotretida
Acrotretida is an extinct order of linguliform brachiopods in the class Lingulata. They lived from the Lower Cambrian to the Middle Devonian, with their peak diversity from the Middle Cambrian to the Ordovician. Acrotretida contains the sole ...
, before being raised to their own order.
Siphonotretids had simple, rounded shells with an ornamentation of hollow spines. The shell is usually ventribiconvex (both valves convex, the ventral valve moreso) and composed of microscopic granules of
apatite
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the three most common e ...
. The inner surface of the shell tends to be weakly mineralized, so many aspects of the musculature and other soft anatomy are difficult to estimate in most species. Available data supports comparison to the internal structures of lingulids. Siphonotretids may be related to the linguloid families
Lingulellotretidae
Lingulellotretidae is an extinct family of brachiopods, with an extended pseudointerarea, including some soft-shelled representatives.
The lingulellotretids are possibly close relatives of the Siphonotretida, Siphonotretids.
Soft tissue is occa ...
or Dysoristidae.
Similar to acrotretides, the pedicle foramen was set at the apex of the ventral valve, though it is often elongated into a tubular groove opening forwards. This groove lies on a triangular extension of the ventral valve, known as a pseudointerarea, which overhangs the dorsal valve. Unlike acrotretides, the adult shell is spinose while the larval shell lacks a pitted texture.
The possible siphonotretid ''
Acanthotretella
''Acanthotretella'' is a genus of brachiopods known from the Burgess Shale
and the Guanshan fauna.
Their spines are proposed to be homologous with those of the Siphonotretids.
Species
* '' Acanthotretella decaius'' Hu, Zhang, Holmer & Skovs ...
'' is known from several exceptionally-preserved specimens which reveal lingulid-like traits such as
setae
In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms.
Animal setae
Protostomes
Annelid setae are stiff bristles present on the body. Th ...
, a spirolophous
lophophore
The lophophore () is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Hyolitha, and Phoronida, which collectively constitute the protostome group Lophophorata.epibenthic lifestyle dissimilar to the
infaunal
Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is ''funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zool ...
Acanthotretella
''Acanthotretella'' is a genus of brachiopods known from the Burgess Shale
and the Guanshan fauna.
Their spines are proposed to be homologous with those of the Siphonotretids.
Species
* '' Acanthotretella decaius'' Hu, Zhang, Holmer & Skovs ...
?'' Holmer & Caron, 2006 (mid-Cambrian, " Stage 4" to
Miaolingian
The Miaolingian is the third Series of the Cambrian Period, and was formally named in 2018. It lasted from about to million years ago and is divided in ascending order into 3 stages: the Wuliuan, Drumian, and Guzhangian. The Miaolingian is prec ...
; provisionally assigned to Siphonotretoidea)
* '' Alichovia'' Goryanskij, 1969 (Ordovician, Tremadoc to
Caradoc
Caradoc Vreichvras (; Modern cy, Caradog Freichfras, ) was a semi-legendary ancestor to the kings of Gwent. He may have lived during the 5th or 6th century. He is remembered in the Matter of Britain as a Knight of the Round Table, under the na ...
)
* '' Celdobolus'' Havlíček, 1982 (Ordovician, Arenig)
* '' Cyrbasiotreta'' Williams & Curry, 1985 (Middle Ordovician, Arenig)
* '' Eosiphonotreta'' Havlíček, 1982 (Lower to Middle Ordovician, Arenig to
Llanvirn
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya.
The ...
)
* '' Gorchakovia'' Popov & Khazanovitch (in Popov et al., 1989) (Upper Cambrian)
* '' Helmersenia'' Pander (in von Helmersen, 1861) (Upper Cambrian to Ordovician)
* '' Karnotreta'' Williams & Curry, 1985 (Middle Ordovician, Arenig)
* '' Mesotreta'' Kutorga, 1848 (Lower to Middle Ordovician, Arenig)
* '' Multispinula'' Rowell, 1962 (Middle to Upper Ordovician, Arenig to Ashgill)
* '' Nushbiella'' Popov (in Kolobova & Popov, 1986) (Middle to Upper Ordovician, Arenig to Caradoc)
* '' Oaxaquiatreta'' Streng, Mellbin, Landing & Keppie, 2011 (Upper Cambrian to
Tremadocian
The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from to million years ago. The base of the Tremadocian is defined as the first appearance of the ...
Silurian
The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...
, late Llandovery to Ludlow)
* '' Quasithambonia?'' Bednarczyk & Biernat, 1978 (Ordovician, Arenig)
* '' Schizambon'' Walcott, 1884 (Middle Cambrian to Ordovician, Arenig)
* '' Siphonobolus'' Havlíček, 1982 (Ordovician, Tremadoc to Arenig)
* ''
Siphonotreta
Siphonotretida is an extinct order of linguliform brachiopods in the class Lingulata. The order is equivalent to the sole superfamily Siphonotretoidea, itself containing the sole family Siphonotretidae. They were most abundant in the Late Cambr ...
'' de Verneuil, 1845 (Ordovician, Arenig to Caradoc)
* '' Siphonotretella'' Popov & Holmer, 1994 (Lower Ordovician, Tremadoc to Arenig)