ACANTHODIAN SCALE REMAINS (STEM CHONDRICHTHYES) FROM THE LOWER DEVONIAN OF QUJING, YUNNAN, CHINA

1. Qiang Li1,2, Plamen Stanislavov Andreev1,2, Xindong Cui2,3, Min Zhu2,3,4*
1 Research Center of Natural History and Culture, Qujing Normal University,
Qujing, China.
2 Key CAS Laboratory of Vertebrate Evolution and Human Origins, Institute of
Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences
(CAS), Beijing, China.
3 University of Chinese Academy of Sciences, Beijing, China.
4 CAS Center for Excellence in Life and Paleoenvironment, Beijing, China.
E-mail of the first author: lq@mail.qjnu.edu.cn
1
ACANTHODIAN SCALE REMAINS (STEM
CHONDRICHTHYES) FROM THE LOWER DEVONIAN OF
QUJING, YUNNAN, CHINA

2. Materials and methods
2
Scale morphology and squamation
3
Summary
4
1 Introduction
Outline

3. Xitun fauna (Lochkovian, Early Devonian)
Illustrated by Brian Choo (2004)
(~ 415 million years ago)
Youngolepis
Psarolepis
Parayunnanolepis
Polybranchiaspis
Origin center for sarcopterygians

4. Lower Devonian Xitun Vertebrate Fauna, Yunnan
Courtesy of M.-M. Chang
Diabolepis
Youngolepis
Psarolepis
Achoania
Parayunnanolepis
Eugaleaspis Polybranchiaspis
Plant Fossils

5. 5
Probably due to the micromeric (small scales or tesserae on the head,
rather than macromeric, with large dermal bones) skeletal nature of
conventionally-defined chondrichthyans and ‘acanthodians’, no cranial
remains of the two groups have been found in the Xitun Formation,
although microfossils from the same bonebeds have been assigned to the
two groups.
‘Acanthodian’ phylogeny prior and after the discovery of Entelognathus

6. Materials and methods
2
Scale morphology and squamation
3
Summary
4
1 Introduction
Outline

7. 7
The materials are based on
isolated scales of Nostolepis
from the Xitun Formation
(Lochkovian, Lower Devonian)
in Xitun, Xishan subdistrict,
Qujing, Yunnan, China
(N:25°31.547′, E:103°31.547′).
Studied scales were extracted
by treatment with buffered 5%
acetic acid from greenish-
yellow muddy limestone of the
Xitun Formation at the
laboratory of Qujing Normal
University.
Sampling sites
Locality map and stratigraphic
position of the fossil bed yielding

8. soak
Washing
Picking
All the acanthodian scales were extracted by treatment with 70% acetic acid
(Concentration is 8%) and 30% acetic acid buffer from samples
Washing the samples with weak water till the reaction is over
Picking some articulated fossils under the microscope and
placing into the oven to dry
Reinforce
Filtrate
Reinforcing some fragmentary fossils
Filtrating the treated particles with
sifters(0.1-2mm)
Picking
Heavy liquids are used to
separate fossils with
residues
Separate
Picking up the
fossils under
microscopes with
brushes
Acid treatment

9. 组织学研究
Histological Research
Embedding Vacuum Cutting Slides
Polishing
Photographing and observation

10. 三维重建志留纪硬骨
鱼鱼鳞及棘刺模型
Reconstruction of microfosills
Digital reconstructions of
specimens used in this PPT are
available
through Admorph:
www.admorph.ivpp.ac.cn.

11. Materials and methods
2
Scale morphology and histology
3
Summary
4
1 Introduction
Outline

12. 12
SEM photos of Nostolepis striata,
Nostolepis amplifica and Nostolepis
consueta scales.
(A)-(H) Nostolepis striata ； (I)-(P) Nostolepis
amplifica ； (Q)-(X) Nostolepis consueta. Scale
bars 0.1 mm.
Histological microstructure and illustrative
drawings of Nostolepis striata, Nostolepis
amplifica, and Nostolepis consueta scales in
vertical longitudinal sections.
(A)-(B) Nostolepis striata； (C)-(D) Nostolepis amplifica；
(E)-(F) Nostolepis consueta. dt-dentine tubule; oc-
osteocyte cavity; stg-Stranggewebe; gl-growth lamella;
avc-ascending vascular canal; sf-Sharpey’s fibers.
Scale bars 0.1 mm.
Nostolepis from Xitun Fauna

13. 13
SEM photos of Nostolepis qujingensis sp.
nov. and Nostolepis digitus sp. nov. scales.
(A)-(H) Nostolepis qujingensis sp. nov (I)-(P)
Nostolepis digitus sp. nov. Scale bars 0.1 mm.
Histological microstructure and illustrative
drawings of Nostolepis qujingensis sp. nov.
(A)-(D) and Nostolepis digitus sp. nov. (E)-(H)
scales in vertical longitudinal sections.
dt-dentine tubule; oc-osteocyte cavity; stg-
Stranggewebe; gl-growth lamella; avc-ascending
vascular canal; sf-Sharpey’s fibers. Scale bars 0.1 mm.

14. 14
Most of these
‘acanthodians’ were
described from the
Devonian. But
Ischnacanthus sp.,
Hanilepis wangi,
Gomphonchus sp.,
Radioporacanthodes
qujingensis,
Gomphonchus
sandelensis and
Ischnacanthidae gen.
indet. were reported
from the Silurian and
Acanthodes cf. A.
dublinensis extends to
the Eifelian.
Stratigraphical ranges of Nostolepis in the world and
acanthodians in China from Silurian to Middle Devonian.

15. 15
Nostolepis distribution in Lower Palaeozoic terranes around 400
Ma (Early Devonian).

16. Hanilepis wangi. SEM micrographs (A-E) and Microstructure (F-H) of trunk scales.
dt-dentine tubule; oc-osteocyte cavity; stg-Stranggewebe; gl-growth lamella; avc-ascending
vascular canal; sf-Sharpey’s fibers. Scale bars 0.1 mm.
Other acanthodians from Xitun Fauna

17. 17
Cheiracanthus xitunensis sp. nov. SEM
micrographs of trunk scales (A-L)
Cheiracanthus xitunensis sp. nov. Microstructure of scales
in longitudinal sections (A-B) and transverse section (E). SEM
micrographs show the enamel and dentine structure at the
crown of longitudinally sectioned trunk scale (C and D, Etched
10 s in 10% HCl). dt-dentine tubule; dentine; gl-growth lamella; el-
enamel. Scale bars 0.1 mm.

18. 18
Tareyacahthus magnificus.
SEM micrographs of trunk scales (A-I).
Tareyacahthus magnificus.
Microstructure of scales in
longitudinal sections (A-D) . C, detail
of posterior edge of crown and a
small portion of base of the same
scale. D, enlarged posterior part of
the same scale.
dt-dentine tubule; oc-osteocyte cavity;
stg-Stranggewebe; gl-growth lamella; avc-
ascending vascular canal. Scale bars 0.1
mm.

19. 19
Changolepis. SEM micrographs (A-E) and Microstructure (F-I) of trunk scales.
dt-dentine tubule; oc-osteocyte cavity; stg-Stranggewebe; gl-growth lamella; avc-
ascending vascular canal; sf-Sharpey’s fibers. Scale bars 0.1 mm.

20. 20
Fibrillosus bulbus gen.et sp.nov.
Microstructure of scales in longitudinal
sections (A-D).
dt-dentine tubule; oc-osteocyte cavity;
stg-Stranggewebe; gl-growth lamella;
avc-ascending vascular canal; sf-
Sharpey’s fibers. Scale bars 0.1 mm.
Fibrillosus bulbus gen. et sp. nov.
SEM micrographs of trunk scales (A-L)

21. Materials and methods
2
Scale morphology and squamation
3
Summary
4
1 Introduction
Outline

22. 22
In summary, we extend the duration of N. striata in China from the Pridoli of
Silurian (Yulungssu Formation) to the Lower Devonian in Qujing and report the
first occurrences of N. amplifica and N. consueta in this region. Most of the
Nostolepis species range from the Upper Silurian to Lower Devonian.
Nostolepis is distributed mainly in the South China, Baltica, Siberia, Laurentia,
and Australia blocks, with rare records in the Arabia, Africa, Sibumasu and
Kazhakstan blocks. Biostratigraphic data of Nostolepis were very similar
between the South China and Baltica blocks. The study has also identified the
presence of Cheiracanthus, Tareyacahthus, Hanilepis and Changolepis, as well
as a new scale-based genus with a peculiar hard tissue structure, i.e.,
Fibrillosus. Cheiracanthus xitunensis sp. nov. was described and most of the
upper horizontal plate in each crown growth zone filled with enamel according
to the section and SEM results, where enamel was confirmed within the stem
Chondrichthyes first time. New acanthodian genus of Fibrillosus is identified at
last. This new genus is based on scales with common morphologic but a very
special histologic characters. This study increases the diversity of the Lower
Devonian Xitun Fauna and provides a better understanding of the
paleogeographic distribution of acanthodians.

23. The areas of Qujing Paleofish Kingdom Museum are nearly 1200 m2, where
has sorts of paleofish fossils from Qujing and its districts.
Qujing Paleofish Kingdom Museum

24. Since its completion in July, it has received nearly 2,000 visitors from
provincial and public institutions, primary and secondary schools.