Olenellus baileyi, Gapp, I. Wesley & Lieberman, Bruce S., 2014

Gapp, I. Wesley & Lieberman, Bruce S., 2014, New olenelloid trilobites from the Northwest Territories, Canada, Zootaxa 3866 (4), pp. 479-498 : 480

Olenellus baileyi sp. nov.

Fig. 1.3, 1.6

Type material. Holotype PWNHC-2013.23.1. Paratype KUMIP 355554. Likely from the Olenellus zone or Waucoban Series, Dyeran stage, sensu Webster (2011a, b) and Webster et al. (2011), early Cambrian, Sekwi Formation, Mackenzie Mountains, Northwest Territories, Canada, but occurring from Section 4 in float.

Etymology. In honour of Hamilton College geologist David G. Bailey, who had an important influence on the professional development of IWG.

Diagnosis. Narrow preglabellar field with plectrum; ocular lobe terminates posteriorly opposite SO; prominent furrow across entire margin of ocular lobe; furrow present across posterior part of LO; extraocular area relatively wide.

Description. Anterior border narrow, length (sag.) 0.5 times length (sag.) of LO, developed as a flattened ledge; anterior border furrow present; preglabellar field present, approximately 15% length (sag.) of LA; plectrum is visible; anterolateral margins of LA angled posteriorly at approximately 40 degrees; length (sag.) LA approximately equal to combined length of LO and L1; S3 convex anteriorly, not conjoined adaxially; L3 length (sag.) equal to length (sag.) LO, lateral margins abaxial to lateral margins of L2; L2 and L3 do not merge abaxially; S2 convex anteriorly, is not conjoined adaxially; length (sag.) L2 equal to length LO; S1 convex anteriorly, creates 40 degree angle with transverse line, conjoined adaxially; lateral margins of LO convex slightly abaxially, furrow across posterior portion on LO.

Discussion. This specimen most closely resembles Olenellus agellus Resser and Howell, 1938 , a species also discussed in Lieberman (1999). Shared characteristics include: presence of a plectrum and short preglabellar field; the lateral margins of LA are abaxial to the lateral margins of LO; S2 is not conjoined adaxially; the ocular lobes have a prominent furrow across the entire margin; and the extraocular area is wide and gently convex. Differences between the two species include: in O. baileyi the lateral margins of L2 do not project beyond the lateral margins of L1, in O. agellus they do; in O. baileyi the posterior margin of the ocular lobes extend back to the abaxial tips of SO, rather than to the adaxial part of the abaxial margin of LO; and in O. baileyi L2 and L3 do not conjoin abaxially.