FIG. 13. — A-F, Nicholsonella spinigera n in A cool-water bryozoan association from the La Pola Formation (Sandbian, Ordovician) of Argentine Precordillera

FIG. 13. — A-F, Nicholsonella spinigera n. sp.: A, B, tangential thin section showing autozooecial apertures, mesozooecia, and acanthostyles, holotype CEGH- UNC 27528 c; C, longitudinal thin section showing autozooecial chambers with diaphragms, holotype CEGH-UNC 27528 b; D, E, branch transverse thin section showing autozooecial chambers with diaphragms and mesozooecia, paratype CEGH-UNC 27538 a; F, branch transverse thin section showing autozooecial chambers and acanthostyles in endozone, paratype CEGH-UNC 27538 a; G-I. Arthroclema sp. A: G, H, branch transverse thin section showing autozooecial chambers, CEGH-UNC 27520 d; I, branch oblique thin section, CEGH-UNC 27529 b. Scale bars: A, E, I, 0.5 mm; B, C, F, G, 0.2 mm; D, 1 mm; H, 0.1 mm.