Pseudoolenoides carterensis Shaw, 1974

Adrain, Jonathan M. & Karim, Talia S., 2012, 3467, Zootaxa 3467, pp. 1-97 : 35-36

Pseudoolenoides carterensis Shaw, 1974

Plates 28–30

1974 Pseudoolenoides carterensis Shaw , p. 25, pl. 1, figs 1–12. 1996 Pseudoolenoides carterensis Shaw ; Fortey and Droser, p. 87.

Material. All specimens are from the Oil Creek Formation (Darriwilian), Oklahoma. Holotype, cranidium, OU 7932 (Pl. 28, figs 3, 6, 9, 12), and illustrated specimens OU 7928 , 7930 , 7934 , 7936–7938 , 30122–30125 , 30128 , 30139 , from Section SP 1 175.6 m, and OU 7931 from Section SP 1 171.0 m, Highway 77 section, Carter County; illustrated specimen OU 7935 from Section AW 1, approximately 122 m, north end of Criner Hills, Carter County ; illustrated specimens OU 7927 , 7929 , 7933 from Section N 1 161.5 m, Carter County ; illustrated specimens OU 38926–38928 , 38930 from Section WSC 107.6 m, West Spring Creek , Murray County .

Diagnosis. Anterior portion of glabella bulbous and entirely lacking sculpture; raised line arc on frontal area more irregular than in any other species; S1 very deep; pygidium lacking flared border behind fourth pleural spine, but with posterior region flared and expanded, forming broad posterolateral extension which merges with the broad base of the posteromedian spine.

Discussion. Pseudoolenoides carterensis is very similar to its sister species, P. fossilmountainensis . However, the species are clearly differentiated, with multiple pervasive differences on each sclerite. Compared with those of P. carterensis , cranidia of P. fossilmountainensis have a significantly shallower anterior border furrow, particularly in the region in front of the glabella; an anteriorly narrower, more anteriorly tapering glabella; less prominent transverse raised line sculpture on the frontal area, lacking forward extensions toward the anterior border and lacking a posterior extension along the facial suture toward the eye ridge; interocular and posterior fixigenae covered with fine, scrobiculate raised line sculpture versus mostly smooth; and less deeply impressed S1. Librigenae of P. fossilmountainensis differ in having a narrower lateral border; a raised line on the field beneath the eye which carries on anteriorly on a straight course, versus bending adaxially; dense but fine raised line sculpture on the field versus mostly smooth; a slightly wider field; and a much narrower and deeper posterior border furrow. Pygidia of P. fossilmountainensis differ in the possession of faint tubercles on the axis versus completely smooth; the presence of a distinct lateral flange of the border behind the fourth pleural spine (see particularly ventral views, Pl. 26, figs 9, 13, to confirm this is a distinct structure), a posterior axis that is much more merged with the postaxial region (in many specimens of P. carterensis , the axis is nearly fully circumscribed posteriorly: Pl. 30, figs 1, 3, 10); and in particular a posterolateral region of the pleura which is small and does not extend posteriorly, versus broad and extended posteriorly to merge with an expanded base of the posteromedian spine.