Acupipora elliptica ( Rogers, 1900 )

Ernst, Andrej, Claussen, Anna Lene, Seuss, Barbara & Wyse Jackson, Patrick N., 2022, Stenolaemate bryozoans from the Graham Formation, Pennsylvanian (Virgilian) at Lost Creek Lake, Texas, USA, Palaeontologia Electronica (a 15) 25 (2), pp. 1-56 : 26

Acupipora elliptica ( Rogers, 1900)

Figures 14E , 15 A-D; Appendix

1900 Polypora elliptica Rogers , p. 7, pl. 4, fig. 2.

1924 Polypora elliptica Rogers, 1900 ; Morgan, p. 116, pl. 37, fig. 9.

1929 Polypora elliptica Rogers, 1900 ; Moore, p. 23-24, pl. 3, figs. 7, 8, 20.

1930 Polypora elliptica Rogers, 1900 ; Sayre, p. 89-90, pl. 3, figs 2-4.

1930 Polypora elliptica Rogers, 1900 ; Moore, p. 155-156.

1937 Polypora elliptica Rogers, 1900 ; Elias, p. 327-328, fig. 3m.

1980 Protoretepora elliptica ( Rogers, 1900) ; Simonsen and Cuffey, p. 15, figs. 3F, 4F, 6F, 7F.

Material. SNSB-BSPG 2020 XCI 60, SNSB-BSPG 2020 XCI 64, SNSB-BSPG 2020 XCI 70, SNSB-BSPG 2020 XCI 77, SNSB-BSPG 2020 XCI 113.

Exterior description. Reticulate colonies composed of moderately wide branches joined by moderately wide dissepiments. Autozooecia arranged in 3–5 alternating rows on branches, 2–3 after bifurcation. Autozooecial apertures rounded to oval, having a prominent rim with spine-like projection toward nearest fenestrule, 3–5 spaced per length of fenestrule. Fenestrules oval to slightly rectangular. Nodes large, elliptical, spaced regularly between autozooecial apertures.

Interior description. Autozooecial chambers moderately long, rectangular to roughly hexagonal in the shallow tangential section, becoming rhombic in the mid and deep tangential sections. Superior hemisepta blunt, placed at the proximal part of the vestibule. Inferior hemisepta well-developed, situated in the distal third of autozooecial chambers. Interior hyaline skeleton well-developed, wrinkled on the reverse side of the branches. External laminated skeleton well-developed, traversed by abundant small microstylets. Microstylets 0.005 –0.010 mm in diameter. Apparent reproductive heterozooecia in form of isolated zooecia with enlarged endozonal chambers present. Chambers rounded, 0.15 mm in diameter. Nanozooecia present.

Remarks. Acupipora elliptica ( Rogers, 1900) is similar to A. mexicana Ernst and Vachard, 2017 , from the Pennsylvanian (Moscovian-Kasimovian) of Mexico but differs from the latter due to the closer spacing of branches (average distance between branch centres 0.88 mm vs. 1.10 mm in A. mexicana ). Acupipora elliptica differs from A. subborealis ( Schulga-Nesterenko, 1951) in having larger fenestrules (fenestrule width 0.27–0.60 mm vs. 0.30–0.40 mm in A. subborealis ; fenestrule length 0.70–0.99 mm vs. 0.70–0.80 mm in A. subborealis ).

Occurrence. Drum Limestone, Pennsylvanian (Missourian); Kansas, USA. Deese Group, Boggy Formation, Pennsylvanian (Missourian); Oklahoma, USA. Topeka Limestone, Pennsylvanian (Virgilian); Kansas, USA. Upper Graham Formation, Pennsylvanian (Virgilian); Texas, USA. Graham Formation, Pennsylvanian (Virgilian); TXV-200 (“Spillway section at Lost Creek Lake”), Texas, USA.

Figures

FIGURE 14. Cavernella praecavifera (Schulga-Nesterenko, 1951) (A–D): A – tangential section showing autozooecial apertures and chambers (XCI 69); B–D – tangential section showing cavernozooecia (arrows) (XCI 73). Acupipora elliptica (Rogers, 1900) (E) – colony fragment showing fenestrules, autozooecial apertures and nodes (XCI 113).

FIGURE 15. Acupipora elliptica (Rogers, 1900) (A–D): A – branch fragment with autozooecial apertures, nodes and nanozooecium (arrow) (XCI 113). B, C – deep tangential section showing autozooecial chambers with hemisepta (XCI 70); D – tangential section showing autozooecial apertures (XCI 70). Polypora triangularis Rogers, 1900 (E–H): E, F – tangential section showing autozooecial apertures and chambers (XCI 50); G, H – tangential section showing autozooecial apertures and reproductive heterozooecia (arrows) (XCI 26).