Exigua

Exigua; Temporal range: Dresbachian PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Trilobita
Order:	Ptychopariida
Superfamily:	Raymondinacea
Family:	Raymondinidae
Subfamily:	Raymondininae
Genus:	Exigua; Howell, 1937
species
	E. quadrata Howell, 1937 (type species) ; E. pulchellus Lochman, 1940 = Brassicicephalus pulchellus ; E. quebeckensis (Rassetti, 1946) = Brassicicephalus quebeckensis ; E. woolfensis (Lochman, 1944) = Brassicicephalus woolfensis ;
Synonyms
	Brassicicephalus

Exigua (synonym: Brassicicephalus) is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived from 501 to 497 million years ago during the Dresbachian faunal stage of the late Cambrian Period.^[3] Exigua is only known from the central part of the headshield or cranidium, so free cheeks (or librigenae), thorax and pygidium are unknown.

Etymology[edit]

Exigua, is Latin meaning small, meager or sparse, referring to the small size of the only parts known of these trilobites, namely the cranidia. The synonym Brassicicephalus is a combination of Brassica (Latin, "cabbage") and κεφαλή, kephalē (Greek: "head") for the strongly convex glabella and fixed cheeks separated by a deep furrow.

References[edit]

^ Robison, R.A. (1988). Peel, J.S. (ed.). Trilobites of the Holm Dal Formation (late Middle Cambrian), central North Greenland. Mededelser om Grønland - Geoscience. Vol. 20. pp. 94–96. ISBN 8763511908.
^ Lochman, C.; Duncan, D. (1944). "Early Upper Cambrian Faunas of Central Montana". Geological Society of America Special Papers. 54: 13. doi:10.1130/spe54-p1. ISBN 0813720540.
^ Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Trilobita entry)". Bulletins of American Paleontology. 364: 560. Archived from the original on 2006-09-05. Retrieved 2008-01-12.

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[1] Robison, R.A. (1988). Peel, J.S. (ed.). Trilobites of the Holm Dal Formation (late Middle Cambrian), central North Greenland. Mededelser om Grønland - Geoscience. Vol. 20. pp. 94–96. ISBN 8763511908.

[2] Lochman, C.; Duncan, D. (1944). "Early Upper Cambrian Faunas of Central Montana". Geological Society of America Special Papers. 54: 13. doi:10.1130/spe54-p1. ISBN 0813720540.

[Sepkoski-3] Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Trilobita entry)". Bulletins of American Paleontology. 364: 560. Archived from the original on 2006-09-05. Retrieved 2008-01-12.

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