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 front of the axis in the head or glabella and the border ridge, and a semi-circular headsheald in the sister-genus Balcoracania. 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).[1]

Emuella
Temporal range: 517 Ma
↓
late Botomian
Emuella polymera  of the Emuella genus; Lower Cambrian Emu Shale, Kangaroo Island, South Australia
(courtesy of Dave Simpson)
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: †Trilobita
Order: †Redlichiida
Family: †Emuellidae
Genus: †Emuella
Pocock, 1970
Species
  • Emuella polymera Pocock, 1970[1]
  • Emuella dalgarnoi Pocock, 1970[1]

Etymology

The genus name means "little emu", and refers to Emu Bay, on Kangaroo Island, one of the sites where fossils of Emuella have been collected. The species epithet polymera is derived from Greek words πολύ -poly- meaning "many"; and μέρος -meros- meaning "part", for the many segmented thorax. E. dalgarnoi is named after R.C. Dalgarno, who discovered Balcoracania dailyi in the Flinders Ranges, near Blinman, South Australia.[2]


References
  1. Paterson, J.R.; Edgecombe, G.D. (2006). "Journal of Paleontology". Journal of Paleontology. 80 (3): 496–513. doi:10.1666/0022-3360(2006)80[496:TECTFE]2.0.CO;2. ISSN 0022-3360.
  2. Pocock, K.J. (1970). "The Emuellidae, a new family of trilobites from the Lower Cambrian of South Australia". Palaeontology. 13: 522–562.

Further information
  • Hagadorn, J.W. (2002). "Burgess Shale-type Localities: The global picture". In Bottjer, D.J.; W. Etter; J.W. Hagadorn; C.M. Tang (eds.). Exceptional Fossil Preservation -- A Unique View on the Evolution of Marine Life. Columbia University Press. ISBN 0231102542.
  • Greg Edgecombe & the Australian Museum. "Australian Trilobites: A Species List and Bibliography". Retrieved August 23, 2005.
  • Sam Gon III. "A guide to the Orders of Trilobites". Retrieved August 23, 2005.
  • Nedin, C. (1995). "The Emu Bay Shale, a Lower Cambrian fossil Lagerstätte, Kangaroo Island, South Australia". Memoirs of the Association of Australasian Palaeontologists. 18: 31–40.
  • Simpson, Dave. "Trilobites of South Australia". Archived from the original on February 19, 2006. Retrieved August 23, 2005.


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