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
Araiophyllum liasicum
Beauvais, 1986
(
Fig. 8
)
Araiophyllum liasicum
Beauvais, 1986: 55
, pl. 12, fig. 3. —
Vasseur 2018: 124-125
, fig. 3.8.
TYPE
MATERIAL. —
Holotype
MNHN
.F.
A32023
(
Beauvais 1986: 55
, pl. 12, fig. 3).
TYPE
HORIZON. —
Pliensbachian
.
TYPE
LOCALITY. — Jebel Bou Dahar,
High Atlas
of
Morocco
. STUDIED SAMPLE. —
Holotype
:
MNHN
.F.
A32023
. GEOGRAPHIC AND STRATIGRAPHIC RANGES. —
Pliensbachian
of
Jebel Bou Dahar
(
Morocco
).
DESCRIPTION (modified after
Beauvais 1986
) Phaceloid colony with subcylindrical corallites multiplying by fissiparous intracalicular budding. The external part of the corallites is covered by an epitheca
s.l.
that reveals some regularly granulated costae. The calicular plateau has been observed on a very few corallites because of a very poor preservation but it shows the characteristic aspect described by
Cuif (1975)
for the genus: a hemispherical shape corresponding to a particular orientation of trabecular axes. Radial elements are totally porous, maybe a few less than in Upper Jurassic microsolenids. However, pores appear more abundant in the axial zone than in the periphery in transverse section because of the orientation of trabecular axes. Moniliform distal edge. Pennulae are numerous. Synapticulae abundant. Endotheca not observed. Weak, parietal papillose columella.
Calicular diameter:
4 to 12 mm
– Number of septa: 92 to 120 – Septal density: 12 per
2 mm
– Trabecular density: 4 to 5 per
1 mm
.
SIMILARITIES AND DIFFERENCES
This species appears very close to the genus
Dermoseris
Koby, 1887
that shows as
Araiophyllum
subhemispheric calices.
Araiophyllum liasicum
differs from
A. triasicum
by the bigger size of the corallites, closer to the dimensions of the Upper Jurassic genus
Dermoseris
.
The more significant difference between the two genera would be the different microstructure of pennulae between
Araiophyllum
and
Dermoseris
: despite the low number of observations, it seems the latter shows regular granulations on the curved edges of pennulae and a more regular alternating disposition (see
Cuif 1975
).