Pliensbachian corals from the Western Tethys
Author
Vasseur, Raphaël
Université de Lorraine, CNRS, lab. GeoRessources, UMR 7359, BP 70239, F- 54506 Vandoeuvre-lès-Nancy cedex (France)
raphaelvasseur@wanadoo.fr
Author
Lathuilière, Bernard
Université de Lorraine, CNRS, lab. GeoRessources, UMR 7359, BP 70239, F- 54506 Vandoeuvre-lès-Nancy cedex (France)
bernard.lathuiliere@univ-lorraine.fr
text
Geodiversitas
2021
2021-11-23
43
22
1187
1291
journal article
10.5252/geodiversitas2021v43a22
1638-9395
5764379
urn:lsid:zoobank.org:pub:6D1643AD-66A5-4678-9397-CE08E610D641
Genus
Trocharea
Etallon
in
Thurmann & Etallon, 1864
SPECIES ORIGINALLY INCLUDED. —
Trocharea actiniformis
Etallon
in
Thurmann & Etallon, 1864
.
TYPE
SPECIES. —
Trocharea actiniformis
Etallon
in
Thurmann & Etallon, 1864
(
Thurmann & Etallon 1864: 411
, pl. 58, fig. 4), by monotypy.
REMARKS
The nature of the relationship between
Trocharea
and
Trochoplegma
Gregory, 1900
is a question which is not completely resolved. One important reason is that the
type
material of
Trocharaea
(
T. actiniformis
Etallon, 1864
) is lost. For
Trochoplegma
the
type
material is housed in Calcutta and has not been revised but we have some ideas of the genus on the basis of topotypes studied by
Beauvais (1978)
or by
Pandey & Fürsich (1993)
.
Alloiteau (1957)
and
Fischer (1969)
remarked that
Trochoplegma
differs from
Trocharea
by its tendency of compactness in septa of first order. They very probably did not see the
type
material or even topotypes and we cannot confirm their criteria. On the basis of topotypes of
Trochoplegma tenuilamellosa
Gregory, 1900
, the
type
species of the genus,
Beauvais (1978)
distinguished the genera with help of two characters: the wall and the epitheca. In
Trochoplegma
the wall would be absent and the epitheca present, when in
Trocharea
the wall would be a synapticulotheca and the epitheca would be absent. We are not certain to be able to differentiate the two character states especially when the notion of pennular envelope (
Gill 1967
) was not taken into account.
Pandey & Fürsich (1993)
maintained the distinction between the genera
Trochoplegma
and
Trocharea
underlining the tendency to become colonial in
Trochoplegma
. In fact they maintained the two genera because the species are quite distinct in the Bathonian of Kachchh. We are not certain of the independence of these genera and we note that several german authors have put the
type
species of
Trochoplegma
or other species of the same genus within the genus
Trocharea
(see
Geyer 1955
;
Flügel 1966
;
Nose 1995
;
Nose & Leinfelder 1997
). The smaller size of trabeculae in
Trochoplegma
, the slightly dipping outward meniana, the exsert character of septa, the tendency toward intracalicular budding, the wavy aspect of septa in distal view are other possible criteria but it seems that all these characters do not always vary together in the same direction (mosaic variation) and could correspond to a variation at the scale of species.
Chomatoseris
Thomas, 1935
is free living and shows a downward growth,
Trochoplegmopsis
Roniewicz, 1976
has subcompact septa and has a papillose columella.