Birds Guide

Casuariidae
Emu
Scientific classification
Kingdom: Animalia   Phylum: Chordata   Class: Aves   Order: Struthioniformes   Family: Casuariidae Kaup, 1847
Genera
Casuarius Dromaius For fossil forms, see article

The bird family Casuariidae has four surviving members: the three species of cassowary, and the only remaining species of Emu. The emus were formerly classified in their own family, Dromaiidae, but are regarded as sufficiently closely related to the cassowaries to be part of the same family.

All four members of the family are very large flightless birds native to Australia-New Guinea. The characteristics of the family are those of its members.

Systematics and evolution

The emus form a distinct subfamily, characterized by legs adapted for running. As with all ratites, there are several contested theories concerning their evolution and relationships. As regards this family, it is especially interesting whether emus or cassowaries are the more primitive form: the latter are generally assumed to retain more plesiomorphic features, but this does not need to be true at all; the fossil record is also ambiguous, and the present state of genomics does not allow for suffiently comprehensive analyses. A combination of all these approaches with considerations of plate tectonics at least is necessary for resolving this issue.

The number of cassowary species described based on minor differences in casque shape and color variations ist quite large. In recent times, however, only 3 species are recognized, and most authorities only acknowledge few subspecies or none at all.

The fossil record of casuariforms is interesting, but not very extensive. Regarding fossil species of Dromaius and Casuarius, see their genus pages.

Some Australian fossils initially believed to be from emus were recognized to represent a distinct genus, Emuarius^[1], which had a cassowary-like skull and femur and an emu-like lower leg and foot. In addition, the first fossils of mihirungs were initially believed to be from giant emus^[2], but these birds were completely unrelated.

Subfamily Casuariinae - cassowaries

• Genus Casuarius
  • Southern Cassowary, Casuarius casuarius
    Dwarf Cassowary, Casuarius bennetti
    Northern Cassowary, Casuarius unappendiculatus

Subfamily Dromaiinae - emus

• Genus Dromaius
  • Emu, Dromaius novaehollandiae
    • Tasmanian Emu, D. n. diemenensis (extinct)
      South-eastern Emu, D. n. novaehollandiae
      South-western Emu, D. n. rothschildi
      Northern Emu, D. n. woodwardi
  • Kangaroo Island Emu, Dromaius baudinianus (extinct)
    King Island Emu, Dromaius ater (extinct)

• Genus Emuarius - "emuwaries" (fossil)
  • Emuarius guljaruba (Late Oligocene - Late Miocene)
  • Emuarius gidju (Wipajiri Early Miocene of Lake Ngapakaldi)

References

• Boles, Walter E. (2001): A new emu (Dromaiinae) from the Late Oligocene Etadunna Formation. Emu 101: 317–321. HTML abstract

Footnotes

1. ^ From "Emu" + "Casuarius". Describer W. E. Boles commonly refers to the genus as "emuwaries" or "cassomus".
2. ^ The vernacular name "mihirung" is derived from mihirung paringmal, which means "giant emu" in the Chaap Wuurong language