Revision of Lithostrotionella - USGS

SYSTEMATIC PALEONTOLOGY 25
Cystolonsdaleia is C. lutugini Fomichev from the Moscovian
of the Donetz Basin. Fomichev also included
Lonsdaleia portlocki {Stuckenberg) of Dobrolyubova
(1935a, b) and Lonsdaleia ivanovi Dobrolyubova (1935a,
b) from the Moscovian of the Moscow Basin and indicated
that species attributed to Stylidophyllum from
the Pe:rmian of China by Yoh and Huang (1932) and
Huang (1932) might belong to the new subgenus. The
Permian species were later reassigned to genera of the
Family W aagenophyllidae by Minato and Kato (1965).
Petalaxis maccoyanus, the type species of Petalaxis,
has an impersistently developed complex axial structure
with the same morphologic elements as the axial structure
of most of the Moscovian species assigned to
Cystolonsdaleia by Fomichev. It seems impractical to
separate these species generically from P. maccoyanus.
The type species of Cystolonsdaleia, C. lutugini, differs
from the other Moscovian species by having a complex
spiderweb columella with inner zone of tabellae distinct
from an outer zone of regular concave tabulae. Accordingly,
Cystolonsdaleia is retained as a separate genus for
this complex species, whereas the other species are placed
in Petalaxis.
De Groot (1964, p. 86) proposed Hillia as a subgenus
of Lithostrotionella for corals from the Bashkirian of
Spain that differ from Lithostrotion by having major
septa that fall short of the columella, horizontal tabulae,
and a columella connected to the cardinal septum; they
differ from true Lithostrotionella by having a poorly
developed lonsdaleoid dissepimentarium.
In other corals that have a columella arising from a
single septum, that septum is the counter septum
wherever the septa can be identified. De Groot gave no
evidence for her conclusion that the septum in Hillia is
the cardinal septum, and her illustrations of species
assigned to Hillia show no basis for that conclusion. The
columella appears to be the same as that seen in many
species of Petalaxis. Moreover, the name Hillia is preoccupied
by Hillia Grote (1883) and Hillia Mallock (1929),
according to Cotton (1974, p. 13), and a replacement
name has not been proposed. In my opinion, the reasons
for separating Hillia de Groot from Petalaxis are insufficient,
and I am reassigning the species of Hillia to
Petalaxis, recognizing them only as a species group
within that genus.
Eastonoides was proposed by Wilson and Langenheim
(1962, p. 511) for a Permian coral that has a columella
composed of an axial plate connected to the counter septum
augmented by rare axial tabellae, slightly sloping
tabulae, and a vertically discontinuous lonsdaleoid
dissepimentarium. Lonsdaleia ivanovi Dobrolyubova
was included as the only other known species referred to
Eastonoides. The essential features of this genus are so
similar to the type species of Petalaxis that I regard
Eastonoides as a junior synonym of Petalaxis, which includes
four other Permian species.
Species of Petalaxis are distinguished on differences
in mature corallite diameter, number of major septa at
maturity, development of minor septa, complexity and
development of the columella, major septal extensions
into the tabularium, major septal extensions into the
dissepimentarium, shape ·and completeness of the
tabulae, spacing of the tabulae, number of rows of
dissepiments, size and shape of the dissepiments, and
the ratio of tabularium width to corallite diameter.
The species of Petalaxis may be arranged in five
species groups:
1. P. simplex group, including simplex, wyomingensis,
tabulatus, bailliei, and tschucoticus. This group
comprises simple forms having mostly complete
tabulae turned up at the columella and a simple
columella; these forms occur in the Lower Carboniferous
(Visean) and lowest Middle Carboniferous
(Namurian).
2. P. jlexuosus group, including flexuosus, donbassicus,
mokmnokensis, exiguus, brokawi, monocyclicus,
sexan~7ulus, taishakuensis, immanis, belinskiensis,
major, fomichevi, and grootae. This group comprises
forms having a simple columella and a narrow
dissepimentarium (large ratio of tabularium
width to corallite diameter); these forms occur in
the Middle Carboniferous (Bashkirian and Moscovian)
and Permian.·
3. P. wagneri group, including wagneri, perapertuensis,
radians, intermedius, santaemariae, cantabricus,
orboensis, and occidentalis. This group
comprises forms having a simple columella and a
weakly lonsdaleoid dissepimentarium; these forms
occur in the Middle Carboniferous (Bashkirian and
Moscovian) and Permian.
4. P. vesiculosus group, including vesiculosus,
lisitschanskensis, exilis, confertus, persubtilis,
korkhovae, mirus, and evidens. This group comprises
forms having a simple columella and a narrow
dissepimentarium (small ratio of tabularium
width to corallite diameter); these forms occur in
the Middle Carboniferous (Bashkirian and Moscovian).
5. P. maccoyanus group, including maccoyanus,
styla:xis, mohikanus, celadensis, elyensis,
dobrolyubovae, donetsensis, and ivanovi. This
group comprises forms having a complex columella;
these forms occur in the Middle Carboniferous
(Moscovian) and Permian.
Occurrence.- Lower Carboniferous (Visean), Middle
Carboniferous (Namurian, Bashkirian, and Moscovian),
and Permian. U.S.S.R., U.S.A., Canada, Spain, Japan,
China(?), Spitzbergen(?).