Stenolaemate bryozoans from the Graham Formation, Pennsylvanian (Virgilian) at Lost Creek Lake, Texas, USA
Author
Ernst, Andrej
Author
Claussen, Anna Lene
Author
Seuss, Barbara
Author
Wyse Jackson, Patrick N.
text
Palaeontologia Electronica
2022
a 15
2022-05-31
25
2
1
56
http://dx.doi.org/10.26879/1174
journal article
294467
10.26879/1174
77c06bea-bbd5-46af-8ef1-f434aa25c6a8
1094-8074
11032471
A4A07D50-3DDB-4E45-A255-1ECCF45F147A
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.
FIGURE 7.
Dyscritella felixi
n. sp.
(A–B): longitudinal thin section of a colony encrusting a brachiopod spine (paratype XCI 87).
Rhombopora lepidodendroides
Meek, 1872
(C–H): C – branch fragment (XCI 102); D, F – colony surface with autozooecial apertures, acanthostyles and aktinotostyles (XCI 102); E – colony surface with autozooecial apertures, acanthostyles and aktinotostyles (XCI 103); G, H – tangential thin section showing autozooecial apertures, acanthostyles and aktinotostyles (XCI 80b).
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
).