Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis
Author
Sandoval, José
text
Geodiversitas
2022
2022-09-15
44
27
801
851
journal article
158824
10.5252/geodiversitas2022v44a27
835cc227-e5c4-4453-a956-07a154f8fa5f
1638-9395
7150329
urn:lsid:zoobank.org:pub:E4896081-9312-4EA6-AE33-AAC44201748E
Witchellia albida
(Buckman, 1926)
[M]
(
Figs 8B
;
11A
;
12
A-D)
Dundryites albidus
Buckman, 1926
: T.A. 6, pl. 687 (HT); 1926: T.A. 7, p. 12.
Witchellia albida
–
Fernández-López 1985: 81
, text-figs 8D, 8E, pl. 5, fig. 6, pl. 6, fig. 3. —
Chandler & Whicher 2015
: pl. 19, figs 2, 3.
Dundryites
aff.
albidus
[M] –
Dietze
et al.
2007: 6
, pl. 3, fig. 1.
Dundryites albidus
[M] –
Dietze
et al.
2007: 6
, pl. 3, fig. 2.
MATERIAL
EXAMINED. —
JAC11.7.5
,
JAC13.
R
.3
,
JAC13.
R
.34
,
JAC22.30.1
,
JAC22.32.5
,
JAC22.35.3
,
JAC22.35.5
,
JAC22.42.7
,
JAC22.42.8
,
JAC22.43.14
,
JAC22.43.15
,
JAC22.43.16
,
JAC22.43.17
,
JAC22.43.18
,
JAC22.44.9
,
JAC22.44.10
,
JAC22.44.11
,
JAC22.
R
.3
,
JAC22.
R
.6
and
JFA
.
R
.1.
MEASUREMENTS. — See
Table 14.
DESCRIPTION
Medium-sized relatively involute macroconchs with medium (U/D varying between 0.23 and 0.30) and shallow umbilicus. The whorl section (
Fig. 11A
) is subrectangular with a subvertical umbilical wall, rounded umbilical edge, almost flat flanks and tabulate ventral area with a high keel. The innermost whorls are not preserved. In the inner whorls, the ribs, some of which arise divided from a small thickening near the umbilical edge, are moderately falcate. Later the ribbing is irregular with a thick rib, which can bifurcate at mid-flank height and is followed by secondary ribbing that is well marked only in the upper part of the flanks where the ribs bend strongly forward. Finally, the ribbing becomes wide and spaced and tends to fade at the BC end. The septal suture, preserved in the specimen JAC22.R.3 (
Fig. 8B
), is complex; L is tripartite, strongly asymmetrical and incised, and the L-U
2
saddle is narrow at the base and incised above.
REMARKS
The Subbetic forms described above are quite similar to the HT of
W. albida
(Buckman, 1926)
, but some are slightly more evolute and have more persistent ribbing.Considering the morphology of the septal suture,
Dietze
et al.
(2007: 13)
excluded
W.albida
from the
Witchelliinae
, restoring the genus
Dundryites
Buckman. According
to these authors, “
D.
”
albidus
Buckman
shows intermediate characters between
Witchellia
and
Sonninites
.
DISTRIBUTION
According to Buckman (1926), the HT of
W. albida
is from the Mollis horizon.
Callomon & Chandler (1990: 97)
cited it from the Trigonalis Subzone (Bj-8). According to
Chandler
et al.
(2006
: fig. 2), the
type
is from the Bj-5 horizon (Ovale Zone), but in the
type
locality the species is also present in the Laeviuscula Zone and Subzone(Bj-10a horizon).At Little
Down
Wood (Dundry Hill,
Somerset
,
England
), this species occurs in the Ovale Zone associated with
W. romanoides
(
Douvillé, 1885
)
,
W. patefactor
(Buckman, 1923)
,
W. pavimentaria
(Buckman, 1927)
,
W. connata
(Buckman, 1927)
,
W.
cf.
jugifera
(
Waagen, 1867
),
W.
cf.
zugophora
(Buckman, 1922)
, and
Fissilobiceras fissilobatum
(
Waagen, 1867
)
, among others, but specimens resembling ‘
Dundryites’
albidus
range upwards into the Laeviuscula Zone (
Dietze
et al.
2007: 5-7
).
Chandler
et al.
(2014)
cited
W. albida
in the Laeviuscula Zone (Trigonalis Subzone, Bj-8b horizon) from Frogden Quarry, Oborne,
Dorset
(
England
). The specimen figured by
Chandler & Whicher (2015)
is from the base of the Laeviuscula Zone (Sayni Subzone). In the Iberian range (
Spain
), the species is common in the Ovale Zone, but it is probably present also in the lower part of the Laeviuscula Zone (Fernández-López 1985: 82). The Subbetic specimens are found in the Laeviuscula Zone (Trigonalis and probably Laeviuscula subzones) of Sierra de Alta Coloma area (Jaén Province) and Rio Fardes area (Granada Province).