Coronavirinae is one of two subfamilies in the family Coronaviridae. It is subdivided into the genera alphacoronavirus, betacoronavirus, gammacoronavirus, and deltacoronavirus. These include phylogenetically compact genogroups of enveloped, positive-sense, single-stranded RNA and with a nucleocapsid of helical symmetry. The genomic size of coronaviruses ranges from approximately 26 to 32 kilobases, extraordinarily large for an RNA virus. Their numbers are growing rapidly with several novel coronaviruses being recently discovered including Middle East respiratory syndrome coronavirus MERS-CoV discovered in 2012.

The genus alphacoronavirus (formerly known as Coronavirus group 1 (CoV-1)) includes subgroups 1a and 1b, which are prototyped by human coronavirus 229E (HCoV-229E) and HCoV-NL63, as well as the newly established species alphacoronavirus 1 (including porcine transmissible gastroenteritis virus [TGEV]), respectively. The genus Betacoronavirus (formerly Betacoronavirus group 2 (Cov-2)) includes several subgroups, with the most prominent (subgroups 2a and 2b) being prototyped by the species Murine coronavirus (including mouse hepatitis virus [MHV]) and severe acute respiratory syndrome-related coronavirus, respectively. The genus alphacoronavirus and betacoronavirus derive from the bat gene pool. The genus gammacoronavirus includes all avian coronaviruses identified until 2009.

Taxonomy

Genus: Alphacoronavirus; type species: Alphacoronavirus 1
Species: Alpaca coronavirus, Alphacoronavirus 1, Human coronavirus 229E, Human Coronavirus NL63, Miniopterus Bat coronavirus 1, Miniopterus Bat coronavirus HKU8, Porcine epidemic diarrhea virus, Rhinolophus Bat coronavirus HKU2, Scotophilus Bat coronavirus 512
Genus Betacoronavirus; type species: Murine coronavirus
Species: Betacoronavirus 1, Human coronavirus HKU1, Murine coronavirus, Pipistrellus Bat coronavirus HKU5, Rousettus Bat coronavirus HKU9, Severe acute respiratory syndrome-related coronavirus, Tylonycteris Bat coronavirus HKU4, MERS-CoV, HCoV-OC43
Genus Deltacoronavirus; type species: Bulbul coronavirus HKU11
Species: Bulbul coronavirus HKU11, Munia coronavirus HKU13, Thrush coronavirus HKU12
Genus Gammacoronavirus; type species: Avian coronavirus
Species: Avian coronavirus, Beluga whale coronavirus SW1


source - Wikipedia