A Unitary Association-based conodont biozonation of the Smithian-Spathian boundary (Early Triassic) and associated biotic crisis from South China
Author
Leu, Marc
Paleontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
Author
Bucher, Hugo
Paleontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Switzerland
Author
Vennemann, Torsten
Author
Bagherpour, Borhan
Author
Ji, Cheng
Author
Brosse, Morgane
Author
Goudemand, Nicolas
text
Swiss Journal of Palaeontology
2022
19
2022-11-22
141
1
1
61
http://dx.doi.org/10.1186/s13358-022-00259-x
journal article
10.1186/s13358-022-00259-x
1664-2384
PMC9681704
36439694
12000082
Novispathodus pingdingshanensis
(
Zhao & Orchard, 2007
)
Fig. 17D–F; M–P, R, S, U, X
, AA, AB, AD, AF
*2007
Neospathodus pingdingshanensis
n. sp.
; Zhao & Orchard, Zhao et al., p.36, pl. 1, fig. 4A–C.
2012a
Novispathodus pingdingshanensis
(Zhao & Orchard)
; Goudemand & Orchard in Goudemand et al., p. 1030–1031, figs. 2B, F, G, I–J, M, P, Q, AD, 3T-U, 6.
2013
Neospathodus pingdingshanensis
Zhao & Orchard
; Chen et al., p 825, fig. 3.10, 3.12.
2013
Neospathodus waageni
subsp. nov.
A; Metcalfe et al., p. 1144, figs. 9.1–9.5, 9.7, 9.8, 9.10.
2014
Novispathodus pingdingshanensis
(Zhao & Orchard)
; Maekawa & Igo in Shigeta, p. 239–240, figs. 171.13–171.31.
2015
Novispathodus pingdingshanensis
(Zhao & Orchard)
; Chen et al., p. 111, 112, figs. 7.1–7.4, 8.5, 8.6.
2016
Novispathodus
ex. gr.
pingdingshanensis
(Zhao & Orchard)
; Komatsu et al., p. 69, figs. 5.4a–5.5c.
2016
Neospathodus robustus
Koike
; Chen & Kolar-Jurkovšek in Chen et al., p. 93, fig. 9.5 (only).
2018
Novispathodus pingdingshanensis
(Zhao & Orchard)
; Maekawa in Maekawa et al., p. 36–37, figs. 20.2–20.18, 21.1–21.13.
2019
Novispathodus pingdingshanensis
(Zhao & Orchard)
; Chen et al., fig. 3, nr. 8.
2019
Novispathodus pingdingshanensis
(Zhao & Orchard)
; Liu et al., p. 13, pl. 3 fig. 5 (only).
Material.
>
100 specimens
.
Diagnosis
(Zhao and Orchard, in
Zhao et al., 2007
; emended by Goudemand, in
Goudemand et al., 2012b
). Small segminate P
1
elements characterized by a length/ height ratio in the range of 1.32–2.34, and about 4–9 robust, wide, mostly fused, and distinctively posteriorly recurved denticles. In lateral view, the basal margin is usually straight. A large, broadly expanded oval to sub-rounded basal cavity is upturned on the inner margin and flat to downturned on the outer margin.
Remarks.
Goudemand (in
Goudemand et al., 2012b
) revised the original diagnosis by noticing that the basal margin is not necessarily straight and therefore, the most strikingly difference to
Nv. waageni
is the denticulation: the denticles axes are distinctively recurved posteriorly whereas in
Nv. waageni
and
Nv. abruptus
,
the denticles are straight, inclined or radiating. Te two or three denticles anterior of the cusp are often clearly asymmetrical and the posterior edge of the element is much shorter than the anterior one. In most sections worldwide,
Nv. pingdingshanensis
first occurs within the positive δ
13
Ccarb
excursion of the latest Smithian and may extend to the earliest Spathian (
Goudemand et al., 2019
;
Leu et al., 2019
;
Zhang et al., 2019
). Some elements within our rich material resemble
Ns. Pingdingshanensis
, but appear to have a relatively small basal cavity, more posteriorly recurved denticles or more numerous denticles that what was previously described for this species. Tese elements (
Figs. 17C, J, K, T
;
18E, I–K
;
19O, Q
;
20H, N–O, S
; here assigned to
N.
ex gr.
pingdingshanensis
) may deserve differentiation in the future. Two elements illustrated by Metcalfe et al., (2013, figs. 9.6, 9.9, p. 1144) as ‘
Neospathodus waageni
subsp. nov.
A’ display a higher anterior end and more recurved denticles than the other elements they included in ‘
Neospathodus waageni
subsp. nov.
A’, which we synonymized with
Ns. pingdingshanensis
: elements like these two elements do not seem to fit in
Ns. pingdingshanensis
and may deserve assignment to a new species. Some further elements resembling
Ns. pingdingshanensis
but distinctively shorter than
Ns. pingdingshanensis
are herein assigned to a new species (
Nv. gryphus
n. sp.
see below).
(See figure on next page.)
Fig. 17
Novispathodinae
from Qiakong,Laren, Shanggang,and Lilong. Magnification is × 80.The scale bar is 400 μm. All elements are considered to be P
1
elements if not specifically identified otherwise.
A–C
,
J
,
T
,
AA
Novispathodus
ex gr.
pingdingshanensis
(Zhao & Orchard)
;
A
, QIA138,PIMUZ 39226;
B
QIA138, PIMUZ 39227;
C
LAR202, PIMUZ 39228;
J
QIA136, PIMUZ 39229;
T
LIL504, PIMUZ 39230;
AA
LIL508,PIMUZ 39231.
D–F
,
M–P
,
R
,
S
,
U
,
X
,
AB
,
AD
Novispathodus pingdingshanensis
(Zhao & Orchard)
;
D
QIA135, PIMUZ 39259;
E
LIL508,PIMUZ 39260;
F
LIL506, PIMUZ 39261;
M
LIL506, PIMUZ 39262;
N
LIL506,PIMUZ 39263;
O
LIL507, PIMUZ 39264;
P
LIL506, PIMUZ 39265;
R
LIL508,PIMUZ 39266;
S
LAR204,PIMUZ 39267;
U
LIL507, PIMUZ 39268;
X
LIL508, PIMUZ 39269;
AB
LIL508, PIMUZ 39270;
AD
LIL508, PIMUZ 39271.
G
,
I
,
Q
Novispathodus
cf.
?
gryphus
n. sp.
;
G
QIA136, PIMUZ 39204;
I
QIA136, PIMUZ 39205;
Q
QIA135, PIMUZ 39206.
H
,
K
,
L
Novispathodus gryphus
n. sp.
;
H
QIA135, PIMUZ 39243;
K
LIL506, PIMUZ 39244;
L
LIL506,PIMUZ 39245.
V
Novispathodus praebrevissimus
n. sp.
; LIL507, PIMUZ 39273.
W
,
Y
,
Z
,
AE
Novispathodus
ex gr.
abruptus
(Orchard)
;
W
LIL505, PIMUZ 39208;
Y
SHA346,PIMUZ 39209;
Z
LIL506, PIMUZ 39210;
AE
SHA346, PIMUZ 39211.
AC
sp. indet.; LIL504, PIMUZ 39295.
AF
Novispathodus pingdingshanensis
(P
1
cluster) (Zhao & Orchard); QIA136, PIMUZ 39272
Fig. 17
(See legend on previous page.)
Occurrence
. Worldwide occurrence.
China
: Jinya/ Waili area,
Guangxi
(
Goudemand et al., 2012b
) Jiarong, southern
Guizhou
(
Chen et al., 2013
,
2015
). Anshun Fm., Qingyan section,
Guizhou
(
Ji et al., 2011
). Chaohu (Zhao et al., 2007, 2008). Daxiakou,
Hubei
(
Zhao et al., 2013
).
Vietnam
: Bac Tuy Fm.,
Xenoceltites variocostatus
and
Tirolites
beds, (
Komatsu et al., 2016
;
Shigeta et al., 2014
).
Canada
:
Scythogondolella mosheri
zone, Wapiti Lake (
Orchard & Zonneveld, 2009
).
Australia
: Hovea Member of Kockatea Shale, upper part of
Neospathodus waageni
Zone, Smithian substage (
Metcalfe et al., 2013
).