Zhangjiagou, Sihetun (IVPP) (Cretaceous to of China)

Where: Liaoning, China (41.6° N, 120.9° E: paleocoordinates 44.3° N, 122.7° E)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Jianshangou Member (Yixian Formation), Late/Upper Barremian to Late/Upper Barremian (130.0 - 122.5 Ma)

• lower part of formation, Jianshangou Bed (for pterosaur at least).

•The Yixian Formation can be subdivided into five units, in ascending order, Lujiatun unit, Lower Lava, Jianshangou unit, Upper Lava, Dawangzhangzi unit, Jingangshan unit, and Huanghuashan unit. Most of the Jehol fossils from the Yixian Formation are preserved in four beds, that is, the Lujiatun bed (recalculated age is 124.0 ± 1.0/1.3 Ma, He et al., 2006), the Jianshangou bed (125.43 ± 0.50/0.88 Ma, Swisher et al., 1999), the Dawangzhangzi bed, and Jinggangshan bed (~122 Ma, Smith et al., 1995).U-Pb dating suggests that the Huangbanjigou section ranges from 124.9 ± 1.7 Ma to 122.8 ± 1.6 Ma (Yang et al., 2007). Chang et al. (2017) obtained Ar/Ar ages of 125.8 ± 1.0 Ma and 126.0 ± 0.8 Ma from the Lujiatun Unit, the lowest part of the Yixian Formation, below the lacustrine shales.

•He et al. (2004) reported a 40Ar/39Ar age of 120.3 ± 0.7 Ma for a tuff layer in the lower part of the Jiufotang Formation, and Chang et al. (2009) obtained a 40Ar/39Ar age of 122.1 ± 0.3 Ma for a tuff layer from the lowermost part of the Jiufotang Formation. Yu et al. (2021) dated an ash bed just above the Yixian/Jiufotang formation boundary to 122.0 ± 0.9 Ma and three tuff beds from the Xiaotaizi section to 118.9 ± 0.8 Ma, 118.8 ± 0.6 Ma, and 118.6 ± 1.1 Ma. These ages suggest that the Jiufotang Formation in Jianchang Basin was deposited at ca. 122.0–118.9 Ma.

•Olierrok et al. (2019) used a selection of U-Pb and 40Ar-39Ar geochronology to place the Barremian–Aptian boundary (the base of the Chron M0r) between 123.8 and 121.8 Ma. The GTS 2020 uses an age of 121.4 Ma for the base of the Aptian, and multiproxy orbital tuning gives an age of 120.2 Ma for the Barremian-Aptian boundary (Leandro et al., 2022). Therefore, the Yixian Formation should be entirely Late Barremian, with the Jiufotang Formation deposited in the Early Aptian (or latest Barremian at its base).

• group of beds-level stratigraphic resolution

Environment/lithology: terrestrial; lithology not reported

Size class: macrofossils

Preservation: adpression

Collected in 1998; reposited in the IVPP

Collection methods: quarrying, surface (in situ), mechanical,

Primary reference: Z.-H. Zhou and X.-L. Wang. 2000. A new species of Caudipteryx from the Yixian Formation of Liaoning, northeast China. Vertebrata PalAsiatica 38(2):111-127 [M. Carrano/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 55682: authorized by Matthew Carrano, entered by Kaitlin Maguire on 02.11.2005, edited by Matthew Carrano

Creative Commons license: CC BY (attribution)

Taxonomic list

Gastropoda
  -
Gastropoda indet.2 Cuvier 1795 snail
Bivalvia
  -
Bivalvia indet.2 Linnaeus 1758 clam
Insecta
 Insecta -
 Ephemeroptera - Hexagenitidae
Hexagenites sp.2 Scudder 1880 mayfly
nymphs
Malacostraca
 Hemicaridea - Spelaeogriphidae
Liaoningogriphus sp.2 Shen et al. 1998
Deuteropoda
  -
Ostracoda indet.2 Latreille 1802 ostracod
Branchiopoda
 Diplostraca -
Spinicaudata indet.2 Linder 1945 clam shrimp
Osteichthyes
 Osteichthyes -
Osteichthyes indet.2 Huxley 1880 bony fish
Reptilia
 Theropoda -
Caudipteryx dongi n. sp. Zhou and Wang 2000 maniraptoran
IVPP V12344
Dilong sp.3 Xu et al. 2004 coelurosaur
IVPP V11579
 Pterosauria - Ctenochasmatidae
Pterofiltrus qiui n. gen. n. sp.1
Pterofiltrus qiui n. gen. n. sp.1 Jiang and Wang 2011 ctenochasmatid
IVPP V12339