A new imbricate echinoderm from Cambrian of North China illustrates spatial distribution and early evolution of Blastozoans

1. A NEW IMBRICATE ECHINODERM FROM CAMBRIAN OF
NORTH CHINA ILLUSTRATES SPATIAL DISTRIBUTION AND
EARLY EVOLUTION OF BLASTOZOANS
Dezhi Wang
Fangchen Zhao
2021.11.27

2. Eocrinoids from China (Cambrian Stage 4)
A, B
E, F
C
Huang et al., 2010; Hu et al., 2010; Liu et al., 2010; Zhao et al.
2015; Zhao et al, 2007; Zhao et al., 2021; Liu et al., 2013
D

3. Geological setting
 All the specimens were co-occurred with numerous hyolithes and
Redlichia trilobites from the bottom of the Mantou Formation.
 Fossils we collected herein can compare with Lepidocystis and
Kinzercystis from the Kinzers Foramtion (Laurentia) and unknown
imbricate eocrinoids from the Jbel Wawrmast Formation (Morroco)
(Sprinkle, 1973; Smith et al., 2013).
Skinner, 2004

4. Systematic palaeontology
Photographs of Gonggongcystis spinosa gen. sp.
nov. (Mantou Formation, North China). (A) Holotype
in general view. (B) Enlarged view of (A), dotted line
partitioning the tessellate and imbricate parts of the
body wall, NIGPAS120101.
Subphylum Blastozoa Sprinkle, 1973
Family Lepidocystoidae Durham, 1968
Type genus: Lepidocystoidea Sprinkle, 1973
Genus Gonggongcystis gen. nov.
Type species: Gonggongcystis spinosa gen. sp. nov.

5. Side view & Plate morphology
Photographs of Gonggongcystis spinosa
gen. sp. nov. (Mantou Formation, North
China (A)-(E) Paratype of Gonggongcystis
spinosa. (A) external view of
Gonggongcystis spinosa. (B) Counterpart of
(A). (C)-(E) is the detailed view of the boxes
in (A), (B). Abbreviations: ar, axial region;
per: perforate extra-axial region; ier,
impeforate extra-axial region; th, theca; ip,
imbricate plates; st, stem; cs, central spine;
is, isolated ossicles; rr, raised rim.

6. Oral region homology
The imbricate blastozoan Lepidocystis cf. L. wanneri Foerste, 1938
Oral surface of the new taxon Gonggongcystis spinosa
Sketch of PBS(Peristomial Border System) B2
by Kammer et al., 2013

7. Brachiole morphology
Lineal drawings of Gonggongcystis spinosa. (A)-(E), brachiole
morphology of Gonggongcystis spinosa. In cross-sectional(A),
aboral(B), side(C), adoral(D), and general views(E). F, sketch of
Gonggongcystis spinosa.

8. Theca morphology
External view of the specimens showing the
imbricate parts of the body wall and the long aboral
appendage with imbricate plating.

9. Stratigraphic distribution
Earliest imbricates
Gonggongcystis is the first
new genus of early
Cambrian imbricate
eocrinoids found in north
China, adding important
information to
palaeogeographical
distribution of early
eocrinoids.

10. CONTEN
TS
Possilble links?
Spatial distribution
Palaeogeographic distribution of Cambrian Series 2 – Miaolingian eocrinoids. Yellow, Cambrian Series 2; Red,
Miaolingian. Earth palaeogeography in Cambrian stage 3 modified from Yang et al., 2015.

11. Total distribution
 Gogiid eocrinoids (Abbr: G) is the most diverse group among all eocrinoid groups.
 Even more gogiid eocrinoids were reported, less than ten taxa in sum indicate low diversity and
morphological disparity of early radiation of eocrinoids in this period.
 The major diversion of Cambrian eocrinoids and exhibits the magnitude of diversion in different eocrinoid
groups
 After undergoing the first diversion event, Miaolingian eocrinoids expand their taxonominc rang rapidly to
other eocrinoid groups: Columnal eocrinoids, Lichenoids, lyracystis and Trachelecrinus eocrinoids. Until
now 50+ species had been reported and studied.

12. Diversity pattern
Sampling bias imposed by an
incomplete and heterogeneous
geological record and the lower
degree of fossil excavation?
Co-evolutionary relationship between the biodiversity
and correspondent marine environment
Prelude of echinoderm early
evolution remains hidden
High-energy, nearshore facies to
more offshore silty marl, finer-
grained carbonate mudstone

13. Conclusions
 Gonggongcystis spinosa documents the earliest occurrence of imbricate eocrinoids in
North China Block. The discovery of this species enriches the taxonomic diversity and
global distributions of early blastozoans.
 Comparing with contemporary imbricate eocrinoids in Laurentia (Lepidocystis,
Kinzercystis), the occurrence of Gonggongcystis shed new light on biogeographic
relationship between North China Block and Laurentia.
 Through generating a new diversity curve of Cambrian echinoderms, a possible link
between the early echinoderm diversification and ROECE (Redlichiid-Oleneliid Extinction
Carbon Isotope Excursion) during Cambrian is also suggested herein.

14. Thank you!