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
Allocoenia
Etallon, 1859
SPECIES
ORIGINALLY
INCLUDED. —
Astrea trochiformis
Michelin, 1847
,
Allocoenia furcata
Etallon, 1859
.
TYPE
SPECIES. —
Allocoenia furcata
Etallon, 1859
, subsequent designation by
Wells (1936: 100)
.
REMARKS
Alloiteau (1952)
and several subsequent authors indicated erroneously
A. trochiformis
Michelin, 1847
as
type
species.
The differences between the genera
Actinastrea
d’Orbigny, 1849
,
Allocoenia
Etallon, 1859
,
Stephanastrea
Etallon, 1864
,
Stelidioseris
Tomes, 1893
Allocoeniopsis
Alloiteau, 1956
and
Chondrocenia
Roniewicz, 1989
remain very difficult and we propose here an assignment to the genus
Allocoenia
for the following reasons:
The genus
Actinastrea
being the most anciently described was defined in the Late Cretaceous and was used in the most lumping practices (see for instance
Geyer 1955
who grouped in
Actinastrea
three species that are today considered as belonging to, at least, two different genera). Despite recent revisions (
Löser 2012
), the status of the genus remains nomenclaturally problematic in the sense that the currently admitted type species
A. goldfussi
d’Orbigny
was not a part of the originally included nominal species (opposition to article 67-2 ICZN). On a taxonomic point of view, it seems that the
lectotype
of
A. goldfussi
(if, after all, we use it as a reference) and also the
lectotype
of
Stelidioseris gibbosa
(another probable species of Late Cretaceous) show septal strong granules near the wall. In
Stelidioseris
, these granules have been misinterpreted by
Löser (2012)
who considered these septal parts, trabecular in nature and dark in thin section, as lacunae. We cannot assign the Liassic samples to these taxa and prefer to place temporarily our samples within
Allocoenia
,
a genus that would also deserve a revision.
The groupings proposed by
Geyer (1955)
that placed within
Actinastrea
the
type
species of
Coenastrea
Etallon, 1862
and
Enallocoenia
d’Orbigny, 1849
seem immoderate. The occurrence of S2 with paliform inner edge, with S3 tending to join on S2 (the septa are free in both latter genera), and globally smaller calices are characteristic for the forms named
Allocoenia
in the present work.
These forms are distinguished from
Cyathocoenia
Duncan, 1867
by the occurrence of a styliform columella.
In the end, the genus differs from
Isastrea
Milne Edward & Haime, 1851
by its straight septa with an often marked angle between confluent septa and the presence of a columella.