Ed Landing, Jonathan B. Antcliffe, Martin D. Brasier and Adam B. English. 2015. Distinguishing Earth’s oldest known bryozoan (Pywackia, late Cambrian) from pennatulacean octocorals (Mesozoic–Recent): Journal of Paleontology, v. 89, p. 292–317. doi: 10.1017/jpa.2014.26.
Figure 1 (p. 293) and Figure 2 (p. 294) in the above article were erroneously produced in black and white in the printed version of the issue originally published on 4 June 2015 by Cambridge University Press in the Journal of Paleontology, volume 89, issue 2, pages 293–317. Figures 1 and 2 are produced here in the intended full color for both digital and printed versions of the article.
Figure 1 Zooaria of the bryozoan Pywackia baileyi from the late Cambrian lower Yudachica Member of the Tiñu Formation, section near Río Salinas, Oaxaca State, Mexico. All specimens from sample Tu-4.95 (Landing et al., 2007a, Table 1); scale bars 0.2 mm long unless otherwise indicated. Abbreviations: a, autozooecium; ad, diaphragm within axial zooecium; az, axial zooecium; d, diaphragm; h, hemiphragm; k, keel; n, probable nanozooid; numbers “1” and “2,” autozooid generations 1 and 2. (1) Wave-abraded proximal extremity, NYSM 17263; (2, 3) proximal extremity showing hemiphragm (shelves and diseppiments (trans-zooecial partitions) in abraded zooecium, “n” at end of lines marks probable nanozooid, NYSM 13511; (4) spike-like proximal extremity, with medial ridge bifurcating into initial part of daughter autozooecium, NYSM 13509; (5) apical end, many zooecia bases filled with late diagenetic dolomite, NYSM 13514; (6–8) medial stem fragment with diaphragms; (6) four dissepiments (d), white line is position of Fig. 1.7; (7) wave-abrasion shown by rounded margins of trilamellar autozooecium; resistant layers (L1, L2) separated by less resistant middle layer (ML) that forms deep recess; disordered granular histology evident throughout fragment and best illustrated in upper right part of figure; (8) remnant of lowest diaphragm in Fig. 1.6 perched on black phosphatic fill of lower part of autozooecium, NYSM 13613; (9) medial stem fragment showing prominent basal internal zooecial ridges and typical longitudinal elongation of autozooecia, NYSM 13515; (10, 11) proximal extremity with area at arrow tip (Fig. 1.10) enlarged (Fig. 1.11) to show rare granular-prismatic fabric along left- and right- lower part of Y-intersection of autozooecial walls (arrow, enlarged figure at limit photomontage system resolution), hypotype NYSM 17264; (12) medial stem fragment with short longitudinal section through phosphate-infilled axial zooecium at base (“az,” outlined by black lines), second generation autozooid (2) with low medial zooecial internal ridge (“k”) at upper left corner, NYSM 17488; (13) transverse section with phosphate-infilled axial zooecium (note partial, NE segment of curved, light gray axial zooecium wall marked by white line with “az” at end of line), first generation autozooecia (designated by “1”) with fragments of second generation autozooecia (“2”); (14) longitudinal section through medial stem fragment shows phosphate-infilled axial zooecium outlined by black lines (note short section of axial zooecium not completely phosphate-infilled below lower “az” symbol, first and second generation autozooecia (“1” and “ 2”) with crenulated walls to left and right of axial zooecium, NYSM 17415; (15) longitudinal section through medial stem fragment shows axial zooecium (“az”) with longitudinal crenulated wall outlined by black lines at base of figure, two diaphragms (“ad”) in axial zooecium, wave-abraded autozooecia walls (bud generation “1”) to left and right of axial zooecium, NYSM 13517.
Figure 2 Zooaria of the bryozoan Pywackia baileyi from the late Cambrian lower Yudachica Member of the Tiñu Formation, section near Río Salinas, Oaxaca State, Mexico. Specimens from sample Tu-4.95 (Landing et al., 2007a, Table 1); scale bars 0.2 mm long unless otherwise indicated. Abbreviations as in Figure 1 caption. (1) typical tube-like form of autozooecia near proximal end of zooarium, individual autozooecium marked by three successive dissepiments (“d”), NYSM 13510; (2) proximal end, as Fig. 2.1 shows succession of diaphragms (“d”) and hemiphragms (“h”) in elongate autozooecium near proximal end, note crenulated internal wall of autozooecium; (3) longitudinally broken medial stem fragment shows uncommon example of axial zooecium (“az”) not infilled with phosphate but with phosphate-replaced axial zooecium wall and axial diaphragm (“ad”), broken bases of first and second daughter autozooecia (“1” and “2”) on left, and sections through more complete generation 1 and 2 autozooecia on right, NYSM 17264.
