Haemocystidium is a 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 parasitic protozoa

Protozoa

Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...

 belonging to the phylum

Phylum

In biology, a phylum The term was coined by Georges Cuvier from Greek φῦλον phylon, "race, stock," related to φυλή phyle, "tribe, clan." is a taxonomic rank below kingdom and above class. "Phylum" is equivalent to the botanical term division....

 Apicomplexia.

History

The genus Haemocystidium was created to give a name to the haemoproteid of a gecko belonging to the genus Hemidactylus

Hemidactylus

Hemidactylus is a genus of the family of typical geckos, Gekkonidae. It is the second-most speciose genus in the family, with about 90 described species, newfound ones being described every few years. These geckos are found in all the tropical regions of the world, extending into the subtropical...

in Sri Lanka

Sri Lanka

Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...

 by Castellani and Willey in 1904. A second species in this genus was described in 1909 by Johnston and Cleland who found pigmented gametocyte

Gametocyte

A gametocyte is a eukaryotic germ cell that divides by mitosis into other gametocytes or by meiosis into gametids during gametogenesis. Male gametocytes are called spermatocytes, and female gametocytes are called oocytes....

s in the blood of the Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

n tortoise

Tortoise

Tortoises are a family of land-dwelling reptiles of the order of turtles . Like their marine cousins, the sea turtles, tortoises are shielded from predators by a shell. The top part of the shell is the carapace, the underside is the plastron, and the two are connected by the bridge. The tortoise...

 Chelodina longicollis. These species were transferred to Haemoproteus in 1926 by Wenyon.

The genus was resurrected by Garnham in 1966 when he created a new generic name - Simondia - for the haemoproteids of chelonian

Chelonian

Chelonian has multiple, interrelated meanings:*Green turtle*Chelonia, the superorder uniting turtles, tortoises and terrapins with the "proto-turtle" Australochelys*Chelonians, monsters from Doctor Who...

s. He followed the opinions of Wenyon, Hewitt and DeGiusti and suggested that all these parasites belonged to the one species - Simondia metchnikovi. He retained the name Haemocystidium for the haemoproteids of lizard

Lizard

Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...

s.

Levine and Campbell in 1971 moved all the species in Simondia and Haemocystidium into Haemoproteus

Haemoproteus

Haemoproteus is a genus of protozoa that are parasitic in birds, reptiles and amphibians. Its name is derived from Greek: Haima - blood and Proteus - a sea god who had the power of assuming different shapes. The name Haemoproteus was first used in the description of Haemoproteus columbae in the...

an opinion that was followed by subsequent authors.

The genus Haemocystidium was resurrected again by Telford in 1996 when he described three new species of protozoa in geckos from Pakistan

Pakistan

Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

.

This genus like those of many protozoa may be further modified once additional DNA sequences are available.

Description

Haemocystidium is distinguished from Plasmodium

Plasmodium

Plasmodium is a genus of parasitic protists. Infection by these organisms is known as malaria. The genus Plasmodium was described in 1885 by Ettore Marchiafava and Angelo Celli. Currently over 200 species of this genus are recognized and new species continue to be described.Of the over 200 known...

by the absence of an asexual cycle in circulating blood cells

It is distinguished from Haemoproteus

Haemoproteus

Haemoproteus is a genus of protozoa that are parasitic in birds, reptiles and amphibians. Its name is derived from Greek: Haima - blood and Proteus - a sea god who had the power of assuming different shapes. The name Haemoproteus was first used in the description of Haemoproteus columbae in the...

by meronts that do not form as pseudocytomeres.