Dyscritella felixi, Ernst & Claussen & Seuss & Wyse Jackson, 2022

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 : 11-13

Dyscritella felixi n. sp.

Figures 6 F-H, 7A-B; Appendix

zoobank.org/ B5FFF8E9-7B9E-4132-8C26-2AF97A7F089B

Etymology. The species is named after Felix, son of Barbara Seuss.

Holotype. SNSB-BSPG 2020 XCI 101.

Paratypes. Thin sections: SNSB-BSPG 2020 XCI 86, SNSB-BSPG 2020 XCI 87, SNSB-BSPG 2020 XCI 88, SNSB-BSPG 2020 XCI 89.

Type locality. TXV-200 (“Spillway section at Lost Creek Lake”), Texas, USA.

Type stratum. Graham Formation, Pennsylvanian (Virgilian).

Diagnosis. Thin encrusting colonies; 5–7 acanthostyles and 1–4 exilazooecia surrounding each autozooecial aperture; maculae absent.

Description. Encrusting colony, 0.40–0.50 mm in thickness. Autozooecial chambers tubular, growing from a thin epitheca. Acanthostyles common to abundant, 5–7 surrounding each autozooecial aperture, originating from base of exozone, moderate to large in size. Diaphragms absent. Exilazooecia small to moderate in size, rounded-angular, 1–4 surrounding each autozooecial aperture. Autozooecial walls granular, 0.008 –0.013 mm thick in endozone; thick, merged, laminated without distinct zooecial boundaries, 0.033 –0.055 mm thick in exozone. Maculae absent.

Remarks. Dyscritella felixi n. sp. is similar to D. inaequalis Girty, 1911 , from the Fayetteville Shale (Mississippian) of Arkansas. The latter species developed ramose colony instead of encrusting ones as in the present species. Furthermore, it has smaller autozooecial apertures. Girty (1911, p. 194) measured 0.14 mm as the maximum size of the autozooecial apertures for his species in contrast to 0.15–0.24 mm in the studied material. Dyscritella felixi n. sp. differs from D. incrustans Dunaeva, 1964 , from the Carboniferous (Serpukhovian-Bashkirian) of the Ukraine in possessing larger autozooecial apertures (aperture width. 0.15–0.24 mm vs. 0.12–0.15 mm in D. incrustans ).

Figures

FIGURE 6. Cystodictya formosa Moore, 1929 (A–B): A – deep tangential section showing autozooecial chambers with hemisepta and vesicular skeleton (XCI 27); B – branch transverse section showing mesotheca, autozooecial chambers and vesicles (XCI 23c). Goniocladia grahamensis Moore, 1929 (C–E): branch fragment showing the shape of fenestrule, ridges on branches and autozooecial apertures with lunaria (XCI 100). Dyscritella felixi n. sp. (F–H): F – colony encrusting a brachiopod spine (holotype XCI 101); G – colony surface showing autozooecial apertures, exilazooecia, and acanthostyles; H – tangential thin section showing autozooecial apertures, exilazooecia, and acanthostyles (paratype XCI 86).