''Protomycena'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of gilled

fungus A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

in the family

Mycenaceae The Mycenaceae are a family of fungi in the order Agaricales. According to the ''Dictionary of the Fungi'' (10th edition, 2008), the family contains 10 genera and 705 species. This is one of several families that were separated from the Tricholo ...

, of order

Agaricales The Agaricales are an order (biology), order of fungi in the division (mycology), division Basidiomycota. As originally conceived, the order contained all the agarics (gilled mushrooms), but subsequent research has shown that not all agarics are ...

. At present it contains the single

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

''Protomycena electra'', known from a single specimen collected in an

amber Amber is fossilized tree resin. Examples of it have been appreciated for its color and natural beauty since the Neolithic times, and worked as a gemstone since antiquity."Amber" (2004). In Maxine N. Lurie and Marc Mappen (eds.) ''Encyclopedia ...

mine in the Cordillera Septentrional area of the

Dominican Republic The Dominican Republic is a country located on the island of Hispaniola in the Greater Antilles of the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean. It shares a Maritime boundary, maritime border with Puerto Rico to the east and ...

. The fruit body of the fungus has a convex

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. The origin of the word "cap" comes from the Old French word "chapeau" which means "head co ...

that is in diameter, with distantly spaced

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

on the underside. The curved stipe is smooth and cylindrical, measuring thick by long, and lacks a

ring (The) Ring(s) may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell Arts, entertainment, and media Film and TV * ''The Ring'' (franchise), a ...

. It resembles

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

(currently living) species of the genus ''

Mycena ''Mycena'' is a genus of about 500 species of fungi. Rarely more than a few centimeters in width, the mushrooms are characterized by a small conical or bell-shaped cap and a thin fragile stem. Most are grey or brown, but a few species have brigh ...

''. ''Protomycena'' is one of only five known agaric fungus species known in the fossil record and the second to be described from Dominican amber.

Discovery and classification

The genus is known only from the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen, a single fruit body (

mushroom A mushroom or toadstool is the fleshy, spore-bearing Sporocarp (fungi), fruiting body of a fungus, typically produced above ground on soil or another food source. ''Toadstool'' generally refers to a poisonous mushroom. The standard for the n ...

) currently residing in the private collection owned by Ettore Morone of

Turin, Italy Turin ( , ; ; , then ) is a city and an important business and cultural centre in northern Italy. It is the capital city of Piedmont and of the Metropolitan City of Turin, and was the first Italian capital from 1861 to 1865. The city is main ...

. The specimen was collected in one of the amber mines in the Cordillera Septentrional area of the island of

Hispaniola Hispaniola (, also ) is an island between Geography of Cuba, Cuba and Geography of Puerto Rico, Puerto Rico in the Greater Antilles of the Caribbean. Hispaniola is the most populous island in the West Indies, and the second-largest by List of C ...

, in the

. The amber is believed to date from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Burdigalian The Burdigalian is, in the geologic timescale, an age (geology), age or stage (stratigraphy), stage in the early Miocene. It spans the time between 20.43 ± 0.05 annum, Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian (sta ...

stage, about 20 to 16 million years before the present. It was first studied by a group of researchers consisting of David Hibbett and Michael Donoghue from

Harvard University Harvard University is a Private university, private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the History of the Puritans in North America, Puritan clergyma ...

, with David Grimaldi of the

American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...

. Hibbett and colleagues published their 1997 type description in the ''

American Journal of Botany The ''American Journal of Botany'' is a monthly peer-reviewed scientific journal which covers all aspects of plant biology. It has been published by the Botanical Society of America since 1914. The journal has an impact factor of 3.038, as of 20 ...

''. The generic name ''Protomycena'' is noted as "first", and "''

''", a modern genus that it resembles. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''electra'' was coined by the authors from the Latin or Greek word for "amber", in reference to the mode of preservation. When it was reported, ''Protomycena electra'' was the third species of fossil agaric fungus to be described. The two species '' Coprinites dominicana'' and '' Aureofungus yaniguaensis'' are also known from the amber mines of the Dominican Republic, while the fourth species '' Archaeomarasmius leggeti'' is from the older,

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

age

New Jersey Amber New Jersey Amber, sometimes called Raritan amber, is amber found in the Raritan Formation, Raritan and Magothy Formations of the Mid-Atlantic states, Central Atlantic (Eastern) coast of the United States. It is dated to the Late Cretaceous, Turoni ...

. With the 2007 publication of a fifth extinct agaric species, '' Palaeoagaracites antiquus'', the minimum age for the order

was pushed back to the

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

(approximately 100 Ma).

Description

The holotype of ''Protomycena'' is a single fruit body without any associated structures, preserved in a piece of clear light yellow polished amber approximately wide. The pileus is in diameter and has a convex shape, sporting a raised central region (an umbo). The pale flesh appears yellowish in the amber, and is smooth and glossy, changing to striate and slightly translucent towards the margin. The pileus margin is striated and slightly flared. The

on the underside of the pileus are broadly attached ( adnate) to the top of the stipe, and distantly spaced—between six and eight gills extend completely from the pileus margin to the stipe. These full-length gills are anastomosed with lamellulae (short gills which do not reach the edge of the stipe from the pileus margin) of varying lengths. The pileus is centered on the curved stipe, which is smooth and cylindrical, measuring thick by long. The stipe lacks a

and rhizoids. The mushroom is preserved with a small liquid and gas-filled bubble, possibly originating from the mushroom itself, which indicates the amber to be very solid and well-sealed. In Hibbett and colleagues' 1997 publication, ''Protomycena'' was placed in the subfamily ''Myceneae'', which at the time was considered part of the family Tricholomataceae; ''Mycena'' is currently classified in the family

. The placement was based solely on the visible structures, or macromorphology of the fruit body. Many of the features which are typically used to

classify Classification is the activity of assigning objects to some pre-existing classes or categories. This is distinct from the task of establishing the classes themselves (for example through cluster analysis). Examples include diagnostic tests, identif ...

species into fungal

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

and subfamilies are based on microscopic features not visible or preserved in the amber specimen. Consequently, the assignment to ''Mycena'' is provisional (the authors also note certain similarities with extant members of '' Marasmius''), and the describing authors leave open the option of treating the genus placement as ''

incertae sedis or is a term used for a taxonomy (biology), 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 ...

'' (uncertain placement) within the

. ''Protomycena'' is distinct from other amber-preserved mushroom taxa such as '' Coprinites'', in the grooved surface of its pileus and its anastomosing gills.

References

External links

Botanical Society of America
Image of amber specimen {{Taxonbar, from=Q1939683 †Protomycena †Protomycena Prehistoric fungi Natural history of Hispaniola Fossil taxa described in 1997 Miocene life Natural history of the Dominican Republic Neogene fungi Monotypic Agaricales genera