View source for Biology:Nevadella

{{Short description|Extinct genus of trilobites}}
{{taxobox
| fossil_range = Late Atdabanian, {{Geological range|524|522}}
| image = Nevadella eucharis USNM PAL 60079.jpg
| image_caption = ''Nevadella eucharis'', type specimen
| regnum = Animalia
| phylum = [[Biology:Arthropoda|Arthropoda]]
| classis = [[Biology:Trilobita|Trilobita]]
| ordo = [[Biology:Redlichiida|Redlichiida]]
| superfamilia = Nevadioidea<ref name='Lieberman 1998'>{{cite journal|last1= Lieberman|first1= B.S.|year= 1998|title= Cladistic Analysis of the Early Cambrian Olenelloid Trilobites|journal= Journal of Paleontology|volume= 72|issue= 1|pages= 59–78|doi= 10.1017/S0022336000024021|bibcode= 1998JPal...72...59L|s2cid= 86307339|url=http://invitestock.free.fr/Cambrien/pdf/Spanish%20fauna/Cladistic%20Analysis%20of%20the%20Early%20Cambrian%20Olenelloid%20Trilobites.pdf}}</ref>
| familia = "Nevadiidae"
| genus = '''''Nevadella'''''
| genus_authority = Raw, 1936
| subdivision_ranks = [[Biology:Species|Species]]
| subdivision = 
* ''N. eucharis'' <small>(Walcott, 1913) ([[Biology:Type|type]])</small> [[Biology:Synonym (taxonomy)|synonym]] ''Callavia eucharis''
* ''N. baculenta'' <small>(Fritz, 1972)</small>
* ''N. cartlandi'' <small>(Raw in Walcott, 1910)</small> synonyms ''Callavia cartlandi'', ''C. cobboldi'', ''C. brevioculata''<ref>{{cite journal|last= Lieberman|first= B. S.|year= 2001|title= Phylogenetic Analysis of the Olenellina Walcott, 1890 (Trilobita, Cambrian)|journal= Journal of Paleontology|volume= 75|number= 1|pages= 96–115|url= http://www.bioone.org/doi/full/10.1666/0022-3360%282001%29075%3C0096%APAOTOW%3E2.0.CO%3B2|doi=10.1666/0022-3360(2001)075<0096:PAOTOW>2.0.CO;2|s2cid= 85656419}}</ref>
* ''N. keelensis'' <small>Abe, 2010</small>
* ''N. mountjoyi'' <small>(Fritz, 1972)</small>
* ''N. perfecta'' <small>(Walcott, 1913)</small> synonym ''Callavia perfecta''
}}

[[Image:Nevadella perfecta USNM PAL 60082.jpg|left|thumb|Several cephalons of ''Nevadella perfecta'', with undamaged glabellas, also showing the strikingly wide cephalic margin]]'''''Nevadella''''' is an extinct genus of trilobites, fossil marine [[Biology:Arthropod|arthropod]]s, with species of average size (about {{convert|5|cm|in|disp=or}} long). It lived during the late Atdabanian stage, which lasted from 530 to 524 million years ago during the early part of the Cambrian Period.<ref name="Sepkoski">{{cite journal | last = Sepkoski| first = Jack| title = A compendium of fossil marine animal genera (Trilobita entry)| journal = Bulletins of American Paleontology| volume = 364| page = 560| year = 2002| url = http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=307&rank=class| access-date = 2008-01-12 }}</ref>

== Etymology ==
The name is derived from ''[[Biology:Nevadia|Nevadia]]'', a related genus.

== Taxonomy ==
''Nevadia'' predates ''Nevadella'' and may include its direct ancestor.

=== Species previously assigned to ''Nevadella'' ===
* ''N. burri'' = ''Pleisionevadella burri''

== Description ==
The body of ''Nevadella'' is very flat dorso-ventrally. The general outline of its thin, lightly calcified [[Biology:Exoskeleton|exoskeleton]] is inverted drop-shaped. The front is rounded, widest at the back of the headshield (or [[Biology:Cephalon (arthropod head)|cephalon]]), and tapering from there to an eventually rounded termination. The central area of the cephalon (or [[Biology:Cephalon (arthropod head)|glabella]]) is distinctly tapered forward, sides slightly concave, but wedging out slightly in the frontal half and with a rounded front (like the silhouette of a slim pawn). The glabella and the frontal margin almost or entirely touch (in jargon: the preglabellar field is short or absent). Cephalic margin at least as wide as the most frontal thoracal segment. The [[Biology:Trilobite#Thorax|thorax]] has 17 to 23 segments, gradually diminishing in size. The pleural spines are long and sickle-shaped. The tailshield (or [[Biology:Trilobite#Pygidium|pygidium]]) is very small and subquadrate in shape.<ref name='Whittington'>{{cite book |author=H. B. Whittington|title=Treatise on Invertebrate Paleontology. Part O, Revised. Trilobita |chapter=Introduction, Order Agnostida, Order Redlichiida |year=1997|display-authors=0}}</ref>

== Distribution ==
Fossils of ''Nevadella'' have been found in the late Atdabanian of the USA (California, Nevada) and Canada (Cordilleran region).
* ''N. eucharis'' is known from the Middle Member of the Poleta Formation, Esmeralda County, Nevada, USA.<ref>[http://paleodb.geology.wisc.edu/cgi-bin/bridge.pl?action=basicCollectionSearch&collection_no=10496 Paleobiology Database]</ref>
* ''N. keelensis'' is known from the Sekwi Formation, Northwest Territories, Canada.<ref>F. R. Abe, B. S. Lieberman, M. C. Pope, K. Dilliard (2010). "New information on olenelline trilobites from the Cambrian Sekwi Formation in northwestern Canada". ''Canadian Journal of Earth Sciences'', 2010, '''47''' (12): 1445–1449.[http://www.nrcresearchpress.com/doi/abs/10.1139/E10-073]</ref><ref>[http://trilobites.lifedesks.org/node/690 Life Desks, Trilobites on line]</ref>
* ''N. mountjoyi'' is known from the Mural Formation, north slope of Mount Mumm, Alberta, Canada.<ref>[http://trilobites.lifedesks.org/node/696 Life Desks, Trilobites on line]</ref>
* ''N. perfecta'' is known from the Mahto Formation, Mumm Peak on the west side of Hitka Pass, western Alberta, Canada.<ref>U. S. National Museum, Catalogue No. 60082.</ref>

== Ecology ==
Contemporary taxa that also occur in the so-called "Nevadella" Zone include ''Esmeraldina'', ''Holmiella'', ''Palmettaspis'', ''[[Biology:Bradyfallotaspis|Bradyfallotaspis]]'', ''[[Biology:Geraldinella|Geraldinella]]'', ''[[Biology:Paranevadella|Paranevadella]]'', ''[[Biology:Nevadia|Nevadia]]'', ''[[Biology:Buenellus|Buenellus]]'', and ''[[Biology:Cirquella|Cirquella]]''.<ref name='Whittington'/>

== Habitat ==
''Nevadella'' species were probably marine bottom dwellers, like all Olenellina.

== References ==
{{Reflist}}

{{Taxonbar|from=Q7003688}}

[[Category:Redlichioidea]]
[[Category:Cambrian genus extinctions]]

{{Sourceattribution|Nevadella}}