Nevadia weeksi

Name: Nevadia weeksi
Walcott, 1910

Order Redlichiida, Suborder Olenellina, Superfamily Fallotaspidoidea, Family Nevadiidae
Locality: left: Esmeralda County, Nevada; right: Goldfield, Nevada
Stratigraphy: left: Montenegro Member of the Campito Formation, Lower Cambrian; right: Poleta Formation, L. Cam.
Remarks: Photos: G. Ast.

Name:  Nevadia weeksi
Walcott, 1910

Order Redlichiida, Suborder Olenellina, Superfamily Fallotaspidoidea, Family Nevadiidae

Locality: Inyo-White Mountains, Eastern California

Stratigraphy: Lower Cambrian , Nevadia-Holmia Faunule, Nevadella Biozone, Campito or Poleta? Fm.

Remarks: Photos courtesy of the White Mountain Research Station, Bishop, Ca.

http://www.wmrs.edu/projects/trilobites/images/trilo4-2.jpg

http://www.wmrs.edu/projects/trilobites/images/trilo4-4.jpg

Discussion:

According to Lieberman (2001), the genus Nevadia Walcott, 1910 has 8 known species:

Nevadia weeksi Walcott, 1910 (type species)

Nevadia bacculenta (Fritz, 1972) [formerly Nevadella bacculenta Fritz, 1972]

Nevadia faceta (Fritz, 1972) [formerly Nevadella faceta Fritz, 1972]

Nevadia ovalis McMenamin, 1987

Nevadia fritzi Lieberman, 2001

Nevadia gracile (Walcott, 1910) [formerly Wanneria? gracile Walcott, 1910]

Nevadia sp. 1 (of Fritz, 1972) [formerly Nevadella sp. 1 Fritz, 1972]

Nevadia sp. 2 (of Fritz, 1972) [formerly Nevadella sp. 2 Fritz, 1972]

Nevadia differs from Nevadella in:

-the relative length (sag.) of LA (L4) is consistently greater in Nevadella than it is in Nevadia (glabella is shorter in Nevadia in general)

-S2 is convex anteriorly in Nevadella and straight in Nevadia

-the intergenal ridge medial of the eye is well developed in Nevadia, but is not visible in Nevadella

-the anterior margin of the medial part of the third thoracic pleural segment is directed anteriorly in Nevadella (in Nevadia it is transverse)

-the third sgment is macropleural in Nevadella, not in Nevadia

-characters of the axial rings and pleural furrows

N. weeksi differs from N. fritzi in that N. fritzi has slightly shorter ocular lobes and a posterior cephalic border which is flexed, rather than transverse (as is N. weeksi)

Reference: Lieberman, B. S. (2001)  Phylogenetic analysis of the Olenellina Walcott, 1890 (Trilobita, Cambrian). Journal of Paleontology, Vol. 75, No. 1, pp. 96-115.