''Paleoleishmania'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of

kinetoplastids Kinetoplastida (or Kinetoplastea, as a class) is a group of flagellated protists belonging to the phylum Euglenozoa, and characterised by the presence of an organelle with a large massed DNA called kinetoplast (hence the name). The organisms are ...

, a

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

group of unicellular parasitic

flagellate A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their ...

protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...

. At present it is placed in the family Trypanosomatidae. The genus contains two species, ''Paleoleishmania neotropicum'' and the type species ''Paleoleishmania proterus''. The genus is known from the Albian aged Burmese amber deposits of northern

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...

and the Burdigalian aged Dominican amber deposits on the island of

Hispaniola Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...

Etymology

The genus name ''Paleoleishmania'' is derived from the Greek ''paleo'' meaning "old" and ''leishmania'' referencing the modern

Leishmaniasis Leishmaniasis is a wide array of clinical manifestations caused by parasites of the trypanosome genus ''Leishmania''. It is generally spread through the bite of phlebotomine sandflies, ''Phlebotomus'' and ''Lutzomyia'', and occurs most freq ...

-causing genus ''

Leishmania ''Leishmania'' is a parasitic protozoan, a single-celled organism of the genus '' Leishmania'' that are responsible for the disease leishmaniasis. They are spread by sandflies of the genus ''Phlebotomus'' in the Old World, and of the genus '' ...

''. All trypanosomes are heteroxenous (requiring more than one obligatory host in order to complete life cycle) or are transmitted through some variation of a vector.

''Paleoleishmania proterus''

The genus was described in 2004 by

George Poinar Jr. George O. Poinar Jr. (born April 25, 1936) is an American 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 Cr ...

and Robert Poinar in the journal '' Protist'' from

amastigotes An amastigote is a protist A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryot ...

, promastigotes and paramastigotes preserved with a blood engorged female '' Palaeomyia burmitis'' sandfly preserved in Burmese amber. The species was named ''Paleoleishmania proterus'' and the genus was erected for fossil digenetic trypanosomes. ''P. proterus'' was the first

kinetoplastid Kinetoplastida (or Kinetoplastea, as a class) is a group of flagellated protists belonging to the phylum Euglenozoa, and characterised by the presence of an organelle with a large massed DNA called kinetoplast (hence the name). The organisms are ...

to be described from the fossil record.

''Paleoleishmania neotropicum''

''Paleoleishmania neotropicum'' is known solely from the holotype specimen, number # P-3–5, amastigotes and paramastigotes associated with the species host, a relatively complete female sandfly of the species '' Lutzomyia adiketis''. ''P. neotropicum'' and ''L. adiketis'' are preserved in a polished piece of amber and thick. The amber specimen is currently residing in the Poinar Amber Collection housed at the Oregon State University in

Corvallis, Oregon Corvallis ( ) is a city and the county seat of Benton County in central western Oregon, United States. It is the principal city of the Corvallis, Oregon Metropolitan Statistical Area, which encompasses all of Benton County. As of the 2020 United ...

. Poinar published his 2008

type description A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have ...

in the journal '' Parasites & Vectors''. During the fly's struggle to escape from the resin, the alimentary tract was ruptured and some ''P. neotropicum'' flagellates leaked from there into the hemocoel. ''P. neotropicum'' and ''L. adiketis'' lived in an environment similar to modern moist tropical rain forests. The morphology of the compact kinetoplast, nucleus, and rear-facing flagellum indicate the species belongs in the family Trypanosomatidae. The preserved amastigotes are between 4 and 7

µm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

and their presence in the fly indicates the digenetic nature of the species. That the species is digenetic excludes the ''

Blastocrithidia ''Blastocrithidia'' is a genus of parasitic flagellate protist belonging to the family Trypanosomatidae. It is a monoxenous parasite of heteropteran insects, mainly inhabiting their hindgut and glands. Characteristics In addition to ''Blast ...

'' as a possible genus placement for the species, while '' Endotrypanum'' is specific to sloths which are not known on Hispaniola past the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...

. The genus ''

Phytomonas ''Phytomonas'' is a genus of trypanosomatids that infect plant species. Initially described using existing genera in the family Trypanosomatidae, such as ''Trypanosoma'' or ''Leishmania'', the nomenclature of ''Phytomonas'' was proposed in 1909 ...

'' is excluded due to it being exclusively found in hemipterans. The paramastigotes range in size from 6 to 10 µm which is within the range for modern ''Leishmania'' species. There are several possible origins for the paramastigotes preserved in the proboscis. They probably developed within the proboscis from an earlier meal of the fly, however they may have been "infective promastigotes" which occur naturally in the mouthparts of some ''Lutzomyia'' species. Though they are currently placed in the same genus, Dr. Poinar notes the likelihood that the two species arose interdependently from each other. It is possible ''P. neotropicum'' is the ancestor of one or more Neotropical ''Leishmania'' clades.

References

{{Taxonbar, from=Q21445997 Trypanosomatida Euglenozoa genera Albian genus first appearances Burdigalian extinctions Burmese amber Fossils of the Dominican Republic Dominican amber Fossil taxa described in 2004 Taxa named by George Poinar Jr.