Palaeoagaracites
Encyclopedia
Palaeoagaracites is an extinct monotypic
genus
of gilled
fungus
in the order Agaricales
. At present it contains the single species
Palaeoagaracites antiquus.
The genus is solely known from the Lower Cretaceous, Upper Albian
stage (about 100 Ma), Burmese amber deposits in Myanmar
. Palaeoagaracites is one of only five known agaric fungal species known in the fossil record, the oldest to be described, and only genus from Burmese amber.
, number "AB-368", a single partial fruiting body
specimen. When described the mushroom
is part of in the private collection of Ron Buckley of Florence, Kentucky
, USA. The collection has been sold and is now owned by Deniz Erin of Istanbul, Turkey. AB-368 was collected from one of the amber mines in the Hukawng Valley
area southwest of Maingkhwan, Kachin State
, Northern Myanmar
. It was first studied by a pair of researchers led by Dr George Poinar
from Oregon State University
who worked with Ron Buckley. Poinar and Buckley published their 2007 type description in Mycological Research
, a journal of the British Mycological Society
. The genus has been assigned the MycoBank
number MB510456, and the species number MB510465.
The generic epithet Palaeoagaracites is Greek
in derivation and is a combination of the words palaeo meaning "old" and agaricon which means "fungus". The specific epithet "antiquus" was coined by the authors possibly from the Latin
for "old" in reference to the age of the specimen.
When published, Palaeoagaracites antiquus was the fifth species of agaric fungus to be described, and the oldest. The three species Aureofungus yaniguaensis
, Coprinites dominicana
and Protomycena electra
are known from the Burdigalian
amber mines of the Dominican Republic
, while the fourth species Archaeomarasmius leggeti
is from the slightly younger Turonian
age New Jersey Amber.
without any associated structures preserved in a rectangular piece of yellow amber approximately 3.25 cm (1.3 in) by 1.25 cm (0.492125984251969 in) by 1 cm (0.393700787401575 in). The pileus
is 2.2 millimetre (0.0866141732283465 in) in diameter and has a convex shape. The flesh
is a bluish-gray color, hairy, and radially furrowed with sixteen grooves visible on the intact section of pileus. The margin is curved slightly inward. The lamellae, or gills, though slightly decomposed, are subdivided into short sections ranging from 85 μm to 110 μm in length. The stipe
was not preserved with the cap. The basidiospore
s, present as both light and dark colored spores on the gill sides, are smooth and oval. Each basidiospore is approximately 3 to 4.5 μm long. While mature light colored spores are present in many agarics, darker colored mature spores are found in some genera.
Palaeoagaracites presents the oldest, and only, evidence of fungal parasitism
by other fungi in the fossil record. The fossil displays a complex interrelationship between three different fungal genera. The preserved P. antiquus cap is host to both a mycoparasitic fungus and a hypermycoparasitic fungus. The surface of the Palaeoagaracites specimen hosts the extinct necrotroph fungus Mycetophagites atrebora
. The mycelia
of Mycetophagites are found across the surface of the P. antiquus pileus, and the hyphae penetrate into the P. antiquus tissues themselves forming necrotic areas. Mycetophagites is in turn host to a hypermycoparasitic necrotrophic fungus species Entropezites patricii
. Hypha
e of Entropezites are preserved penetrating the Mycetophagites hyphae, forming areas of decomposing tissue. Entropezites also displays a range of growth stages for probable zygospore
s.
The combined distinguishable characters of Palaeoagaracites were not enough for Poinar and Buckley to place the genus further than Agaricales incertae sedis
. The overall size, shape of the spores, and structure of the cap hint at a relationship to the genera Mycena
, Marasmius
and Collybia
. All three of these genera are members of the family Tricholomataceae
.
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
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of gilled
Agaricales
The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record...
fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
in the order Agaricales
Agaricales
The fungal order Agaricales, also known as gilled mushrooms , or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13000 described species, along with five extinct genera known only from the fossil record...
. At present it contains the single 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...
Palaeoagaracites antiquus.
The genus is solely known from the Lower Cretaceous, Upper Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...
stage (about 100 Ma), Burmese amber deposits in Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
. Palaeoagaracites is one of only five known agaric fungal species known in the fossil record, the oldest to be described, and only genus from Burmese amber.
History and classification
The genus is known only from the single holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
, number "AB-368", a single partial fruiting body
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
specimen. When described the mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
is part of in the private collection of Ron Buckley of Florence, Kentucky
Florence, Kentucky
Florence is a city in Boone County, Kentucky, United States. The population was 29,951 at the 2010 census.-History:The Florence area was originally known as Crossroads, because of the convergence of several roads from Burlington and Union at Ridge Road...
, USA. The collection has been sold and is now owned by Deniz Erin of Istanbul, Turkey. AB-368 was collected from one of the amber mines in the Hukawng Valley
Hukawng Valley
The Hukawng Valley is an isolated valley in Burma, roughly in area. It is located in Tanaing Township in the Myitkyina District of Kachin State in the northernmost part of the country.-Rivers:...
area southwest of Maingkhwan, Kachin State
Kachin State
Kachin State , is the northernmost state of Burma. It is bordered by China to the north and east; Shan State to the south; and Sagaing Division and India to the west. It lies between north latitude 23° 27' and 28° 25' longitude 96° 0' and 98° 44'. The area of Kachin State is . The capital of the...
, Northern Myanmar
Myanmar
Burma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
. It was first studied by a pair of researchers led by Dr George Poinar
George Poinar, Jr.
George O. Poinar, Jr. is an entomologist and writer. He is known for popularizing the idea of extracting DNA from insects fossilized in amber, an idea which received widespread attention when adapted by Michael Crichton for the book and movie Jurassic Park.Poinar earned a B.S. and M.S. at Cornell...
from Oregon State University
Oregon State University
Oregon State University is a coeducational, public research university located in Corvallis, Oregon, United States. The university offers undergraduate, graduate and doctoral degrees and a multitude of research opportunities. There are more than 200 academic degree programs offered through the...
who worked with Ron Buckley. Poinar and Buckley published their 2007 type description in Mycological Research
Mycological Research
Fungal Biology is a scientific journal that publishes peer-reviewed papers on all aspects of basic and applied research of the fungi, including lichens, yeasts, oomycetes, and slime moulds.- History :...
, a journal of the British Mycological Society
British Mycological Society
The British Mycological Society is a learned society established in 1896 to promote the study of fungi.-Formation:The Society was formed based on the efforts of two local societies, the Woolhope Naturalists' Field Club of Hereford and the Yorkshire Naturalists’ Union. The curator of the Hereford...
. The genus has been assigned the MycoBank
MycoBank
MycoBank is an online database, documenting new mycological names and combinations, eventually combined with descriptions and illustrations. It is run by the Centraalbureau voor Schimmelcultures fungal biodiversity center in Utrecht....
number MB510456, and the species number MB510465.
The generic epithet Palaeoagaracites is 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;...
in derivation and is a combination of the words palaeo meaning "old" and agaricon which means "fungus". The specific epithet "antiquus" was coined by the authors possibly from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "old" in reference to the age of the specimen.
When published, Palaeoagaracites antiquus was the fifth species of agaric fungus to be described, and the oldest. The three species Aureofungus yaniguaensis
Aureofungus
Aureofungus is an extinct monotypic genus of gilled fungus in the order Agaricales. At present it contains the single species Aureofungus yaniguaensis....
, Coprinites dominicana
Coprinites
Coprinites is an extinct monotypic genus of gilled fungus in the Agaricales family Agaricaceae. At present it contains the single species Coprinites dominicana....
and Protomycena electra
Protomycena
Protomycena is an extinct monotypic genus of gilled fungus in the Mycenaceae family, of order Agaricales. At present it contains the single species Protomycena electra, known from a single specimen collected in an amber mine in the Cordillera Septentrional area of the Dominican Republic...
are known from the Burdigalian
Burdigalian
The Burdigalian is, in the geologic timescale, an age or stage in the early Miocene. It spans the time between 20.43 ± 0.05 Ma and 15.97 ± 0.05 Ma...
amber mines of the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
, while the fourth species Archaeomarasmius leggeti
Archaeomarasmius
Archaeomarasmius is an extinct genus of gilled fungus in the Agaricales family Tricholomataceae, containing the single species Archaeomarasmius leggetti. It is known from two fruit bodies recovered from amber, one consisting of a complete cap with a broken stem, the other consisting of a fragment...
is from the slightly younger Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
age New Jersey Amber.
Description
The holotype of Palaeoagaracites is a single, partly decomposed fruit bodyBasidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
without any associated structures preserved in a rectangular piece of yellow amber approximately 3.25 cm (1.3 in) by 1.25 cm (0.492125984251969 in) by 1 cm (0.393700787401575 in). The pileus
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
is 2.2 millimetre (0.0866141732283465 in) in diameter and has a convex shape. The flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....
is a bluish-gray color, hairy, and radially furrowed with sixteen grooves visible on the intact section of pileus. The margin is curved slightly inward. The lamellae, or gills, though slightly decomposed, are subdivided into short sections ranging from 85 μm to 110 μm in length. The stipe
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
was not preserved with the cap. The basidiospore
Basidiospore
A basidiospore is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. In grills under a cap of one common species in the phylum of...
s, present as both light and dark colored spores on the gill sides, are smooth and oval. Each basidiospore is approximately 3 to 4.5 μm long. While mature light colored spores are present in many agarics, darker colored mature spores are found in some genera.
Palaeoagaracites presents the oldest, and only, evidence of fungal parasitism
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
by other fungi in the fossil record. The fossil displays a complex interrelationship between three different fungal genera. The preserved P. antiquus cap is host to both a mycoparasitic fungus and a hypermycoparasitic fungus. The surface of the Palaeoagaracites specimen hosts the extinct necrotroph fungus Mycetophagites atrebora
Mycetophagites
Mycetophagites is an extinct monotypic genus of mycoparasitic fungus in the order Hypocreales. At present it contains the single species Mycetophagites atrebora....
. The mycelia
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...
of Mycetophagites are found across the surface of the P. antiquus pileus, and the hyphae penetrate into the P. antiquus tissues themselves forming necrotic areas. Mycetophagites is in turn host to a hypermycoparasitic necrotrophic fungus species Entropezites patricii
Entropezites
Entropezites is an extinct monotypic genus of hypermycoparasitic fungus in the order Hypocreales. At present it contains the single species Entropezites patricii....
. Hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e of Entropezites are preserved penetrating the Mycetophagites hyphae, forming areas of decomposing tissue. Entropezites also displays a range of growth stages for probable zygospore
Zygospore
A zygospore is a diploid reproductive stage in the life cycle of many fungi and protists. Zygospores are created by the nuclear fusion of haploid cells. In fungi, zygospores are termed chlamydospores and are formed after the fusion of hyphae of different mating types...
s.
The combined distinguishable characters of Palaeoagaracites were not enough for Poinar and Buckley to place the genus further than Agaricales incertae sedis
Incertae sedis
, is a term used to define a taxonomic group where its broader relationships are unknown or undefined. Uncertainty at specific taxonomic levels is attributed by , , and similar terms.-Examples:*The fossil plant Paradinandra suecica could not be assigned to any...
. The overall size, shape of the spores, and structure of the cap hint at a relationship to the genera Mycena
Mycena
Mycena is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or brown, but a few species have brighter colors. Most have a...
, Marasmius
Marasmius
Marasmius is a genus of mushrooms, in the family Marasmiaceae. It contains about 500 species of agarics, of which a few, such as Marasmius oreades, are edible. However, most members of this genus are small, unimpressive brown mushrooms...
and Collybia
Collybia
Collybia is a genus of mushrooms in the Tricholomataceae family. The genus has a widespread but rare distribution in north temperate areas, and contains three species that grow on the decomposing remains of other mushrooms....
. All three of these genera are members of the family Tricholomataceae
Tricholomataceae
The Tricholomataceae are a large family of mushrooms within the Agaricales. A classic "wastebasket taxon", the Tricholomataceae is inclusive of any white-, yellow-, or pink-spored genera in the Agaricales not already classified as belonging to the Amanitaceae, Lepiotaceae, Hygrophoraceae,...
.