''Haematractidium'' is a genus of parasitic alveolates in the phylum

Apicomplexa The Apicomplexa (also called Apicomplexia; single: apicomplexan) are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of non-photosynthetic plastid called an ap ...

. It infects the Atlantic mackerel (''

Scomber scombrus The Atlantic mackerel (''Scomber scombrus''), also known as Boston mackerel, Norwegian mackerel, Scottish mackerel or just mackerel, is a species of mackerel found in the temperate waters of the Mediterranean Sea, the Black Sea, and the northern ...

'').

History

This genus was first described by Henry in 1910. Although it is occasionally re described very little is known about it.

Taxonomy

There is one known species in this genus: ''Haematractidium scombri''.

Description

The parasite is intra erythrocytic, ameboid, oval or pyriform in shape. There are no vacuoles or reticulation in the cytoplasm. The nucleus has two or more chromatin granules. The parasite has a single membrane.

References

Apicomplexa genera Parasites of fish {{Apicomplexa-stub