''Balcoracania dailyi'' is a small (typically about )

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

of the family Emuellidae. Its fossils have been found in south Australia and Antarctica. It can be recognised by a short field between the front of the axis in the head (or glabella) and the border ridge, and a semi-circular headsheald, as compared to touching glabella and border, and the sub-pentagonal head, in the sister-genus ''

Emuella ''Emuella'' is a genus of trilobites of the family Emuellidae. Its fossils have been found in South Australia. It can be recognised by touching glabella and frontal border, and the sub-pentagonal head, as compared to, a short field between the f ...

''. Both emuellid genera share eye ridges that are positioned parallel to the frontal and lateral border of the head, prominent genal spines that are a smooth continuation of the lateral margin of the head, a prothorax of 6 segments, with the 5th and 6th merged and carrying large trailing spines. Both genera have in adulthood a highly variable but large number of segments of the opistothorax, although the largest number found in ''B. dailyi'' with 97 is much larger than in ''Emuella'' (52). ''B. dailyi'' is the only known species in this genus (i.e., the genus is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

Etymology

The genus name is derived from Balcoracana Creek in the Flinders Ranges, one of the sites where fossils of ''Balcoracania'' were collected. The species

epithet An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

''dailyi'' is in honor of Dr. B. Daily, of the Geology Department, University of Adelaide.

Ecology

''Balcoracania dailyi'' was an inhabitant of protected, shallow, marginal, marine environments. ''B. dailyi'' is usually the only trilobite present, but brachiopods may be present, too. Tubular burrows show it shared its ecosystem with soft-bodied animals.

References

Emuelloidea Cambrian trilobites of Antarctica Cambrian trilobites of Australia Emu Bay Shale {{redlichiida-stub Cambrian genus extinctions