Hedbergella trocoidea Gandolfi 1942 from: Moullade, M.Bellier, J.P.Tronchetti, G. (2002): Hierarchy of criteria, evolutionary processes and taxonomic simplification in the classification of Lower Cretaceous planktonic foraminifera . Cretaceous Research Vol. 23 p. 111-148 | . |
Notice: This catalogue page may contain unedited data.
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Species Hedbergella trocoidea Gandolfi 1942 |
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| Alternative name: |
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| Discussion / Comments: |
Caron (1985):
The species with usually 7 chambers forming the last whorl is
distinctly larger than morphologicalty similar Hedbergella
species like H. planispira and also possesses a slightly higher trochospire.
Bellier & Moullade (2002):
Despite numerous works, there still remain some
problems concerning the acceptance and taxonomic
status of Hedbergella trocoidea, as well as its probable
phylogenetic ancestor, Praehedbergella praetrocoidea.
Praehedbergella praetrocoidea was created by
Kretchmar and Gorbachik (1986) for what we consider
as an intermediate morphologic stage (6-7 chambers
in the last whorl) between Praehedbergella infracretacea
(typically 5-chambered) and H.
trocoidea (7-8). However, BouDagher-Fadel et al.
assumed that :
- P. praetrocoidea is an endemic species, restricted
to the Crimean Peninsula;
- H. trocoidea is cosmopolitan;
- P. praetrocoidea has a microperforate wall
structure, devoid of muricae, and thus has to be attributed
to the genus Blefuscuiana (=Praehedbergella
in our opinion; we do not follow the artificially
restricted concept suggested by Banner and Desai,
1988 for the genus Praehedbergella, which was created
by Gorbachik and Moullade, 1973; see Moullade,
Bellier and Tronchetti, submitted).
In 1998, BouDagher-Fadel et al. also showed that
H. trocoidea has a macroperforate wall and muricae.
But their observations were made on upper Aptian
Crimean and lower Albian Tunisian material. Nothing
is said about a possible re-examination of material
from the type-locality, as well as Gandolfi's initial
description and illustrations. In 1997, the
authors described H. trocoidea as having only 6 to 7
chambers in the last whorl but the illustrations of
BouDagher-Fadel et al. (1998) show specimens ranging
from 6.5 to 8 chambers.
In its type-locality (Breggia River section, N. Italy),
H. trocoidea, a typically 7-8 chambered form on the
basis of the original illustrations, was described
(Gandolfi, 1942) from supposedly Aptian or Albian
beds. In the Vocontian area (Moullade, 1966), as well
as in ODP Leg 171B (Bellier et al., 2000) specimens
attributable to H. trocoidea are abundant as early as
the tapper Aptian/lowermost Albian, and then disappear
within the lower Albian. Later in Leg 171B sites
this species seems to reappear, with very rare specimens found in the upper Albian (see also Gradstein,
1978, DSDP Leg 44). The "H. trocoidea-like" morphotypes
are extremely rare in the Vocontian region
during the late Albian. The material originally illustrated
by Gandolfi (1942) comes from level 14, which
is presumably Aptian, of the Breggia River section.
Our examination of upper Albian assemblages
from the Breggia River section (levels 27 and 28 of
Gandolfi), including TicineUa roberti, "Biticinella"
breggiensis, HedbergeUa delrioeusis, Rotalipora subticinensis,
etc., show the co-occurrence, together
with this upper Albian assemblage, of some specimens
morphologically very similar to H. trocoidea.
In fact, in the micropaleontological literature, this
species is frequently cited from levels extending from
the upper Aptian to the upper Albian.
The "first" LO of H. trocoidea in Site 1049 occurs
in the H. planispira Zone, in the lower Albian, in accordance
with Moullade, 1974. In Sites 1050 and
1052, very similar morphotypes (PI. 1, fig. 16-18)
"reoccur" in the upper part of the Rotalipora ticinensis
Zone (in which, as in the Breggia River material
mentioned above, they seem to evolve towards
Ticinella roberti) and reach the lower part of the R.
appennininica Zone.
Therefore, the first problem is to discern whether
this represents two stratigraphically disjunct, homeomorphic
taxa, or a single species with two periods
of occurrence, separated by a middle Albian
gap owing to unfavorable (ecologic/paleoceanographic)
conditions.
The poor to moderate preservation of the Breggia
material does not permit detailed observation of the
wall microstructure of the examined specimens. But
in the Leg 171B material, both upper Aptian/lower
Albian and upper Albian specimens (all with 7-8
chambers) attributable to H. trocoidea show a macroperforate
wall and features that we interpret as
muricae rather than perforation cones. This observation
is consistent with BouDagher-Fadel et al.
(1997), who suggest assignment of this species to the
genus Hedbergella.
In addition, a minor microstructural evolution is
discernable in our material : the upper Aptian specimens
(P1. 1, fig. 10-12) show muricae only on the
first or second chambers of the last whorl, whereas
the upper Albian forms, referred to as Hedbergella
almadenensis (P1. l, fig. 16-18), have muricae on all
but the last chambers.
Out of this small microstructural difference there
are also some characteristics that lead us to characterize
the upper Albian specimens and to distinguish
them from the upper Aptian-lower Albian forms, including
:
- periphery slightly more lobate;
- umbilical flaps and area more developed;
- less protruding chambers towards the umbilicus;
- intercameral sutures slightly arcuate, instead of
straight tin umbilical view);
- diameter/height ratio slightly higher;
- aperture slightly higher and less wide (i.e. less
extended to the periphery).
Moreover, the two forms have different ticinellid
phylogenetic successors; Ticinella eubejaouaensis
evolved in the latest Aptian from the Aptian morphotypes
and T. roberti from the upper Albian ones.
All these features lead to the conclusion that the
two populations represent two homeomorphs and,
thus, two distinct species, as was pointed out by
Moullade (1969), who restricted the concept of the
species H. trocoidea to the upper Aptian-lower
Albian stock and attributed the upper Albian forms
to Globigerina almadeneusis CUSHMAN and TODD,
1948. We examined SEM pictures (communicated by
B.T. Huber) of the type material of this latter taxon,
which is deposited in the collections of the National
Museum of Natural History (Washington D.C.).
Unfortunately, most of the type specimens are very
poorly preserved. However, one of the paratypes looks
similar to our material from Leg 171B and to that
of the Vocontian region (in Moullade, 1969, pl. 1,
fig. 19-20). Instead of erecting a new name, we are
therefore led to use Hedbergella almadenensis for
these upper Albian homeomorphs of the upper
Aptian-lower Albian H. trocoidea.
Boudagher-Fadel et al. (1997):
Remarks: This species is characterized by
having six to seven chambers in the last whorl, a
convex dorsal side and a concave ventral side with
a broad umbilicus. It evolved from Blefuscuiana
praetrocoidea (Kretchmar and Gorbachik) in the
Aptian by acquiring muricae over the early whorls
and macroperforations (BouDagher-Fade1 et al.,
1997a).
Pflaumann & Krasheninnikov (1977):
This species had been described from late Aptian to Albian
section of Switzerland, Bavaria, France, Trinidad, Rumania, and
Mexico. |
| Systematics: |
5
Classis Foraminifera
Familia Globotruncanidae
Genus Hedbergella
Species Hedbergella trocoidea
22
Familia Globotruncanidae
Subfamilia Hedbergellinae
Genus Hedbergella
Species Hedbergella trocoidea
52
Familia Rotaliporidae
Subfamilia Hedbergellinae
Genus Hedbergella
Species Hedbergella trocoidea
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| Synonym list: |
Moullade et al. (2002):
Caron (1985):
Loeblich & Tappan (1961):
1942 Anomalina lorneiana d'Orbigny. - Gandolfi : p.98 pl. 4, fig. 1, 19;
pl. 8, fig. 2;
pl. 13, fig. 1, 4
Bellier & Moullade (2002):
1974 Hedbergella trocoidea Gandolfi. - Longoria : p.69 (pars) pl. 17, fig. 1-9;
(non) pl. 17, fig. 10-16;
pl. 18, fig. 3-5
1997 Hedbergella trocoidea Gandolfi. - Boudagher-Fadel et al. : p. 7, 207 pl. 1.1, fig. 7,
pl. 11.1, fig. 4;
Figure: 8.2
1997 Hedbergella trocoidea Gandolfi. - Boudagher-Fadel et al. : p.5 pl. 2; fig. 1-9 (q.v. for full synonymy)
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| References: |
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Ricerche micropaleontologiche e stratigraphiche sulla Scaglia e sul Flysch cretacici dei dintorni di Balerna (Canton Ticino) . Rivista Italiana di PaleontologiaMemoria 4 p. 1-160
Cushman,J.A. and Todd,R. (1948):
A foraminiferal fauna from the New Almaden District California . Contributions from the Cushman Foundation for Foraminiferal Research Vol. 24 p. 90–98
North,R.. (1951):
Foraminiferen aus der Unter- und Oberkreide des Österreichischen Anteils an Flysch, Helvetikum und Vorlandvorkommen . Austria, Geol. Bundesanst., Jahrb., Sonderband Vol. 3 p. 1-91(pls.1-9)
Brönnimann,P. and Brown,N.K. (1956):
Taxonomy of the Globotruncanidae . Ecoglae geologicae Helvetiae Vol. 48 p. 503-561
Brönnimann,P. and Brown,J.N.K.. (1958):
Hedbergella, a new name for a Cretaceous planktonic foraminiferal genus . Washington Acad. Sci., Jour. Vol. 48(1) p. 15-17
Banner,F.T. and Blow,W.H. (1959):
The classification and stratigraphical distribution of the Globigerinaceae . Paleontology Vol. 1(2) p. 1-27
Bolli,H.M. (1959):
Planktonic foraminifera from the Cretaceous of Trinidad, B.W.I. . Bulletins of American Paleontology Vol. 39 p. 257-277
Loeblich,A.R. and Tappan,H. (1961):
Cretaceous planktonic foraminifera: Part I-Cenomanian . Micropaleontology Vol. 7 p. 257-304
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Etude stratigraphique et micropaléontologique du Crétacé inférieur de la "fosse vocontienne" . Documents des Laboratoires de Géologie de la Faculté des Sciences de Lyon Vol. 15 p. 1-369
Moullade,M. (1969):
Sur l’importance des phénomènes de convergence morphologique chez les Foraminifères planctoniques du Crétacé inférieur . Proceedings of the First International Conference on Planktonic Microfossils, Geneva 1967 Vol. 2 p. 460-467
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On some type specimens of Cretaceous planktonic foraminifera . Contrib. Cushman Found. Foram. Res. Vol. 20 p. 23
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Stratigraphic, morphologic and taxonomic studies of Aptian planktonic Foraminifera . Revista Espanola de MicropaleontologíaNo extraord p. 1-107
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