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 striata
n. sp.
[M]
(
Figs 11D
;
13
G-H)
urn:lsid:zoobank.org:act:
565D9D7B-5E38-4DA9-82A3-74C76491E98B
Witchellia rubra
–
Sandoval 1990: 146
, pl. 1, fig.7,
non
Buckman, 1926.
DIAGNOSIS. — Macroconch, planulate, relatively involute with shallow umbilicus, compressed rectangular section with a very shallow depression in the lower part of the flanks, tabulate venter with a relatively high hollow keel. Weak falcate ribbing that progressively fades, being replaced by bundles of striae. The septal suture is simple.
TYPE MATERIAL
. —
Holotype
: specimen JAC11.4.27, held in the
Department of Stratigraphy
and
Palaeontology
,
Faculty of Sciences
,
University of Granada
(
Spain
).
TYPE
LOCALITY AND OCCURRENCE
. —
Sierra Alta Coloma
(JAC11 section;
Jaén Province
), central sector of the Median Subbetic,
Betic Cordillera
, S
Spain
,
Lower Bajocian
(Laeviuscula Zone, Trigonalis Subzone)
.
DERIVATION OF NAME. — Ornamentation composed mainly of striae.
MATERIAL
EXAMINED. — Two specimens: JAC4.36.1, JAC11.4.27 (
HT
).
MEASUREMENTS. — See
Table 20.
DESCRIPTION
Planulate semi-involute, medium-sized shells, with appreciable uncoiling throughout ontogeny and with medium-wide, shallow umbilicus. An almost rectangular compressed whorl section (
Fig. 11D
), which has a vertical umbilical wall, an abrupt umbilical edge at right angles, and almost flat flanks with a very shallow depression (barely noticeable) in its lower part. The venter is clearly tabulate with a high hollow keel. The aperture is not well preserved, although the
holotype
is almost complete and appears to be adult. The inner and middle whorls support fine falcate ribs, which are single or divided into the inner third of the flanks. The weak and poorly marked secondaries strongly project forward along the ventrolateral edge. From the last part of the
PH
, ribbing progressively weakens, being replaced by bundles of striae or by very faint ribs in the BC. The septal suture, typical of
Witchellia
, has short lobes and low saddles.
REMARKS
These Subbetic forms are quite similar to the HT of
W. hyalina
but are slightly more involute, have less marked ribs on inner whorls, falcate rather than sinuous ornamentation, and bear striae that form bundles in the BC. Moreover, the new species appears to be chronostratigraphically earlier.
W. romanoides
is more evolute, has any depression in the lower part of the flank and has more pronounced and less striate ornamentation.
TABLE 21. — Measurements of
Witchellia peleka
(Buckman, 1923)
[m].
Specimen
|
D
|
U
|
u
|
H
|
h
|
W
|
w
|
Remarks
|
Biostratigraphy
|
MOD.R.1 |
27.0 |
9.5 |
0.35 |
10.0 |
0.37 |
– |
– |
JAC11.(3-7).1 |
32.0 |
12.2 |
0.38 |
11.5 |
0.36 |
7.5 |
0.23 |
22.0 |
8.4 |
0.38 |
8.7 |
0.40 |
– |
– |
JAC11.R.54 |
35.0 |
12.5 |
0.36 |
12.0 |
0.34 |
– |
– |
25.0 |
8.0 |
0.32 |
10.6 |
0.42 |
– |
– |
Adult microconchs |
Ovale Zone |
TT.76.1 |
35.0 |
13.0 |
0.37 |
12.5 |
0.36 |
– |
– |
26.0 |
9.0 |
0.35 |
11.0 |
0.42 |
– |
– |
JSP.1 |
29.0 |
10.5 |
0.36 |
10.2 |
0.35 |
– |
– |
23.0 |
7.8 |
0.34 |
8.5 |
0.37 |
– |
– |
DISTRIBUTION
Laeviuscula Zone, Trigonalis Subzone; Sierra de Alta Coloma (sections JAC4 and JAC11; Jaén Province).