www.sciencemag.org/content/363/6433/1338/suppl/DC1

Supplementary Materials for

The Qingjiang biota—A Burgess Shale–type fossil Lagerstätte from the

early Cambrian of South China

Dongjing Fu, Guanghui Tong, Tao Dai, Wei Liu, Yuning Yang, Yuan Zhang, Linhao

Cui, Luoyang Li, Hao Yun, Yu Wu, Ao Sun, Cong Liu, Wenrui Pei, Robert R. Gaines,

Xingliang Zhang*

*Corresponding author. Email: xzhang69@nwu.edu.cn

Published 22 March 2019, Science 363, 1338 (2019)

DOI: 10.1126/science.aau8800

This PDF file includes:

Materials and Methods

Figs. S1 to S11

Table S1

References

1

Materials and Methods

Contents:

1. Field collections and repository information

2. Fossil data sets

3. Statistical method.

4. Stratigraphy and age

5. Biotic composition

6. Environment of preservation

1. Field collections and repository information. The majority of specimens were collected

from two meter-scale intervals of alternating event-background claystone bed sets in the

middle member of the Shuijingtuo Formation at the Jingyangkou Section, ca. 4 km northwest

of Changyang County, Hubei Province (Fig. 1). The two claystone intervals that bear

exceptional fossils are separated by a one to four meter thick interval of planar laminated

black siltstone, which can be traced 20 km west through a number of well exposed sections.

These sections were measured, sampled and described in the field. Observations of these

sections in the Changyang region were compiled to produce a generalized composite section

(Fig. 1C). To date, collection efforts outside the Jingyangkou section have been limited, but

have so far yielded hundreds of complete sponge specimens (Fig. 2E) and several specimens

of soft-bodied arthropods (Leanchoilia sp. and Naraoia spinosa). All fossils are reposited at

the Department of Geology, Northwest University, Xi’an, China. Specimens were

photographed immersed in water to enhance contrast. Rock samples were analyzed in thin

section and polished slab for primary physical attributes. Whole rock geochemical analysis of

major and trace elements was conducted on samples of claystone prepared as fused

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borosilicate glass beads using a Panalytical Axios X-Ray Fluorescence spectrometer. Weight

percent organic carbon and pyrite sulfur were measured by combustion using an Elementar

VarioMicro Cube Elemental Analyzer.

2. Fossil data sets. 4351 specimens (751 algal specimens and 3600 metazoan specimens)

have so far been catalogued and are included in this study. Fossils were identified to the

lowest possible taxonomic rank (usually genus). Algal specimens were classified into

morphological groups but not assigned to specific phylogenetic groups, with those specimens

that cannot be placed in any known (described) genus simply referred to as new forms.

Metazoan specimens that can be definitively categorized into phylum- or superphylum-rank

groups but represent new genus-level or higher taxa were referred to as new taxa. Those new

taxa that cannot be placed with confidence into high taxonomic groups (e.g a superphylum)

were identified as new problematic taxa. The Chancelloriida is usually regarded as a

problematic metazoan clade but is treated here as a group within basal metazoans for its

simple body plan similar to the Porifera.

3. Statistical method. EstimateS 9.1.0 (http://www.viceroy.eeb.uconn.edu/EstimateS/) was

used to compute individual-based rarefaction curves to allow diversity comparisons between

different BST assemblages.

4. Stratigraphy and age. The Shuijingtuo Formation is widely distributed in the study area

(Changyang) and, in general, consists of three members (29, 31, 32) (Fig. 1). Member I is

comprised of laminated black shale and siltstone and contains meter-sized carbonate

concretions. Overlying it, member II—which contains the Qingjiang biota—is a black

carbonaceous siltstone with subordinate claystone that occurs in two prominent meter-scale

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intervals. Member III is a black, decimeter-centimeter- bedded, carbonaceous limestone with

thin mudstone partings.

The Eodiscoid trilobites Tsunyidiscus and Sinodiscus (Fig. S3A, B) are characteristic

shelly taxa of the Shuijingtuo Formation, and accordingly the Sinodiscus-Tsunyidiscus

Assemblage Zone was erected (33−35) in the Yangtze Gorges area and correlated to the

Chiungchusuan Stage of eastern Yunnan based on the mixture of trilobite faunas in that area

(17, 36−39). In eastern Yunnan, the Chiungchusuan Stage, equivalent to the upper part of

Cambrian Stage 3 as currently defined (19), comprises two trilobite zones, the Parabadiella

huoi Zone and the overlying Eoredlichia-Wutingaspis Assemblage Zone that contains the

Chengjiang biota (39,40). The presence of Tsunyidiscus in the Chengjiang biota (40) and the

presence of Eoredlichia in the Shuijingtuo Formation (41) indicate that the Qingjiang biota

reported here is equivalent to the Chengjiang biota in age, and may be correlated to the global

Cambrian Series 2 and Stage 3 (19). The occurrence of a specimen of Eoredlichia intermedia

(Fig. S3C) in background claystone beds in the fossiliferous interval of the type locality of the

Qingjiang biota provides robust evidence for the correlation with the Chengjiang biota. This

correlation is further reinforced by the presence of conspecific fossils shared between the two

biotas, e.g. Xianguangia sinica, Heliomedusa orienta, Naraoia spinosa, Misszhouia

longicaudata, Branchiocaris yunnanensis, Combinivalvula chengjiangensis and Sunella

grandis.

5. Biotic composition. Shelly fossils occur preferentially in the dark-colored claystones,

and are relatively rare in event-deposited claystones. These include trilobites, bradoriids,

brachiopods, hyolithids, mollusks, chancelloriids, articulated sponge spicules, and the

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problematic tubular fossil Sphenothallus. The shelly fossil composition of the “background

beds” in the excavated intervals is consistent with that previously described from the

Shuijingtuo Formation in the study area (17). To date, over 100 metazoan genera have been

recognized from the event beds. The majority can be comfortably placed into 18 known body

plans across all subkingdom-rank lineages (Fig. S4). A number of bilaterians that cannot be

readily assigned to any known body plan are present, including a taxon reminiscent of

Pollingeria, previously known from the Burgess Shale, and 5 new taxa. Each may represent a

different bodyplan.

Ecdysozoans are by far the most diverse group in the Qingjiang biota. As is the case in

other Burgess Shale-type Lagerstätten, arthropods dominate the fauna, and are represented by

30 genera, including 10 new taxa. Additionally, lower stem group euarthropods are

represented by four anomalocaridid genera (Fig. S2F), including two new taxa, and two new

lobopodian genera (e.g. Fig. 3D). Priapulids are much less abundant than in the Chengjiang

biota (n=32, <1% of specimens), and comprise six genera, three of which are new (e.g. Fig.

2E). Unexpectedly, kinorhynchs (Fig. 3C), which are rarely known in the fossil record, are

quite abundant in the Qingjiang biota, with over 400 specimens representing three new taxa.

Within the Deuterostomia, new enteropneust and chordate taxa (e.g. Fig. 2F) have so far been

recognized, though each of these groups is presently represented by a small number of

specimens. A few specimens with a pentaradial symmetry are tentatively assigned to the

Echinodermata. Additionally, a number of enigmatic (stem-group) deuterostomes, i.e.

Eldonia, Yunnanozoon (Fig. 2G), vetulicolians (Fig. S2M) and Banffia are present.

Lophotrochozoans have a relatively low taxonomic diversity. Hyoliths are common, with

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273 specimens comprising Archotuba, Ambrolinevitus, Burithes, and three new taxa.

Currently only eight brachiopod specimens are known. These include three previously known

genera and one new taxon. Specimens of Heliomedusa in particular show exquisitely

preserved soft anatomy, as also observed at Chengjiang. A single specimen of mollusk

representing a new taxon has been so far recovered. Dinomischus (Fig. S2L) is also present

and provisionally placed within the Lophotrochozoa, with affinity uncertain. Additionally, two

incomplete specimens resembling Burgessochaeta are tentatively assigned to the Annelida.

Basal metazoan lineages are particularly well represented in the Qingjiang biota. The

Porifera, dominated by demosponges, show a high taxonomic diversity, with 15 genera

identified from 366 complete specimens, six of which represent new genus-rank taxa and the

remainder shared with Chengjiang or other Burgess Shale-type biotas. Cnidarians are the most

abundant fossil group in the Qingjiang biota, accounting for 35% of all specimens. Both

medusa and polyp body forms are present (Fig 2A, B). Among the 1674 specimens of

cnidarians, nine taxa have so far been recognized. The anemone Xianguangia is common to

the Chengjiang biota, but the other eight taxa, including anemones and jellyfish, are new.

Ctenophores are less common, but nevertheless two new taxa have so far been recognized

(e.g. Fig. 2C). Chancelloriids are represented by a handful of specimens of Allonnia.

Algae are abundant, diverse, and remarkably preserved with sporangia (Fig. S8A).

Forms include simple filaments (Fig. S2J), spiral filaments, and branched and unbranched

ribbons or tubes. Most strikingly, one form is dichotomously branched from a central disc into

a four-fold radial symmetry (Fig. 2D). To our knowledge, this morphology is completely

novel. At least eight algal forms have so far been recognized, with two taxa, Fuxianospira

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gyrate and Sinocylindra yunnanensis, shared with the Chengjiang biota, and the remainder

identified as new forms.

6. Environment of preservation. BST deposits are widely distributed in the Cambrian of

South China, encompassing a variety of regions and paleoenvironments (4). Generally the

Qingjiang fossils appear to have been preserved in a more distal environment than the

Chengjiang fossils, as the Qingjiang lies close to the shelf break (Fig. 1). However, the

Chengjiang and Qingjiang biotas, separated by ca. 1050 km, were deposited under different

paleoenvironmental regimes, the former in a shelf environment near exposed land, and the

latter in a more distal shelf environment offshore from two carbonate platforms that

developed nearby (Figs. S9, S11). As currently understood the Chengjiang assemblage

includes a mixed composition of components buried in situ and those transported from nearby

environments (13, 20). The Qingjiang assemblage appears similar in this respect (see

discussion below). A short transport distance is necessary for excellent preservation.

Therefore, both Qingjiang and Chengjiang assemblages represent communities developed in

response to local environmental conditions. The differences in biotic composition (Fig. S6)

are thus interpreted as primary ecological differences, rather than artefacts of taphonomic

bias.

The two sets of calcareous claystones with distinctive couplets comprised of alternating

black and light gray beds can be traced 20 km west, and are present at a number of localities

along this transect (Fig. 1). These localities have not yet been excavated systematically, but

reconnaissance collection has revealed that many also yield well-preserved soft-bodied fossils

(Fig. 2E). During the deposition of the fossil-bearing interval, a small carbonate platform

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represented by the contemporaneous Liujiapo Formation was developed some 80 km

northeast of the type locality (29) (Fig. S9). Facies relationships indicate that a muddy slope

or ramp descended from this platform to the study area, providing a pathway for gravity-

driven mudflows. The black beds are interpreted as pelagic “background” sedimentation from

settling of clay particles, while the light gray colored beds represent event-deposited

sediments, as indicated by the presence of small rip-up clasts, a randomly-oriented clay

microfabric, and the presence of soft-bodied fossils at multiple angles to bedding and

embedded entirely within the gray beds, rather than at bed junctions. There are many small

event beds (1 mm or less) dispersed throughout the background intervals (Fig. S1B). The

absence of silt or sand grains and the lack of primary sedimentary structures aside from sharp

bedding contacts indicate that the depositional environment lay below storm wave base but

episodically received gravity-driven sedimentation events set up by storm waves higher on the

slope. The presence of small rip-up clasts (Fig. S1C) indicates that the mudflows were

sufficiently strong and turbulent to rip up consolidated pieces of the claystone substrate, and

also suggest that cementation of the substrate was early and occurred near the sediment-water

interface.

The presence of a limited benthic fauna in some horizons within the background

sediments indicates the bottom water was at least intermittently oxygenated in order to

support sessile epibenthos (e.g. sponges and brachiopods) and vagile epibenthos (e.g.

hyoliths, bradoriids and polymerid trilobites). The complete absence of bioturbation in both

background and event sediments, which is confirmed by thin section and polished slab

analyses (Fig. S1C), suggests that bottom waters were not sufficiently oxygenated to support

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the activity of an infauna. Therefore, infaunal components must have been transported from

nearby oxic settings that lay upslope (Fig. S11). Geochemical results suggest dominantly

anoxic or potentially euxinic conditions in the lower water column during the deposition of

the fossil-bearing interval (Fig. S10). Samples exhibit significant enrichment in the redox

sensitive trace element molybdenum (Enrichment Factor 3.8-12.5, average 7.3) with lower

enrichments of uranium (EF 1.1-5.3, average 2.2) and no enrichment of vanadium (EF 0.9-

1.1; average 1.0). These patterns are consistent with an active sulfur cycle in the water column

(euxinia) and/or a depleted oceanic inventory of U and V. Collectively, these data demonstrate

generally oxygen deficient conditions that occasionally permitted colonization of the benthic

realm by epifaunal organisms (Fig. 4; Fig. S11) but persistently excluded colonization by an

infauna. Consequently, the Qingjiang assemblage contains both organisms buried in situ and

those transported a short distance from nearby habitats. These organisms were trapped in

gravity-driven mudflows and rapidly buried in sediments that must have become anoxic

rapidly after burial (Fig. S11). The assemblage appears to represents a primary community

that flourished in a nearby environment upslope of the sites of preservation.

9

Supplementary Fig. 1. Claystones from the fossil-bearing interval of the Jinyangkou

section. (A) laminated claystones in outcrop. (B) a polished slab showing characteristic

couplets of background and event beds, note many submillimeter thick micro-event beds and

absence of bioturbation. (C) thin section from the interval figured in (B), showing ovoid

millimeter-scale rip-up clasts (gray) oriented roughly parallel to bedding.

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Supplementary Fig. 2. Soft-bodied fossils from the Qingjiang biota. (A) Naraoia spinosa,

showing exquisitely preserved gut diverticulae. (B) new species of Naraoia, distinguished

from other species of Naraoia by the presence of one pair of marginal spines (Sp) at the mid-

length of the posterior shield. (C) new arthropod, note that two trunk segments share a single

pleural spine. (D) new vermiform fossil of undetermined phylogenetic position. (E)

magnification of the boxed area in (D), showing dense pitted structures. (F) frontal appendage

of an anomalocaridid. (G) a larval form. (H) new sponge. (I) Choiaella cf. radiata. (J) new

alga. (K) a tubular fossil preserved with internal organs. (L) Dinomischus sp. (M) a new

taxon of vetulicolian, note gills (Gi) and mouth (Mo) of anterior body.

11

Supplementary Fig. 3. Biostratigraphic marker fossils from Member II of the

Shuijingtuo Formation at the Jinyangkou section. (A) and (B), Tsunyidiscus acutus and

Sinodiscus changyangensis, two iconic trilobites of the Shujingtuo Formation. (C),

Eoredlichia intermedia, from the Jinyangkou section, an index fossil for the Eoredlichia-

Wutingaspis Assemblage Zone of easternYunnan, the stratigraphic level that yields the

Chengjiang biota.

12

Supplementary Fig. 4. Comparison of communities in Cambrian BST biotas. Rarefaction

curves showing potential for the highest relative species diversity in the Qingjiang biota.

Composition of community data matrix used for rarefaction analyses is given in Table S1.

13

Supplementary Fig. 5. Diagram showing taxonomic diversity and specimen abundance

for major taxonomic groups of the Qingjiang biota. For each fraction in the right column

the numerator represents the number of new taxa (pink) and the denominator represents the

total number of taxa (blue) for each bodyplan. Note that the diagram is based on preliminary

results because many taxa are yet undescribed.

14

Supplementary Fig. 6. Taxonomic comparison of relative diversity within high ranking

taxonomic groups in the Qingjiang and Chengjiang biotas. The diagram for the

Chengjiang biota was modified from (7, fig. 6.1).

15

Supplementary Fig. 7. Soft-bodied tissues preserved as carbonaceous compressions. (A)

Optical photograph of Naraoia spinosa from the Qingjiang biota, showing details of gut

diverticulae. (B) Back Scattered Electron image of the boxed area in (A) showing framboidal

aggregates of micron-sized pyrite crystals scattered in spaces between gut diverticulae. (C-L)

EDS elemental maps of the boxed area in (A) note that the gut diverticulae are deficient in

iron (G) and sulfur (H), but are enriched in carbon (I).

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Supplementary Fig. 8. Algal fossils preserved as organic remains. (A) optical photograph

of an alga from the Qingjiang biota, showing sporangia preserved in low 3D relief. (B) Back

Scattered Electron image of the boxed area in (A). (C-L), EDS elemental maps of the boxed

area in (A), note that the sporangia are enriched in carbon (I) but deficient in sulfur (S) and

calcium (K).

17

Supplementary Fig. 9. Regional early Cambrian stratigraphy and distribution of

lithofacies in the study area. Note that the fossil-bearing Shuijingtuo Formation passes

laterally into the carbonate-dominated Liujiapo Formation to the northeast. Modified from

(29, fig. 3.2).

Supplementary Fig. 10. Concentrations of the redox sensitive elements. Vanadium,

Uranium and Molybdenum, as well as the major element Aluminum (modeled as the oxide

Al2O3), for nine samples of the fossil-bearing claystones from the Jinyangkou section, as

determined by X-Ray Fluorescence. Enrichment factors (EF) were calculated by normalizing

to Aluminum and comparison to average upper continental crust (42).

18

Supplementary Fig. 11. Depositional and biostratinomic setting of the Qingjiang biota,

showing ecological niches and inferred location of the chemocline with respect to the loci

of preservation. A muddy slope descended from the carbonate platform and was separated

into an oxic upslope setting with infauna and an anoxic downslope setting that lacked infauna.

The oxycline may have at times extended to the water-sediment interface as evidenced by the

intermittent presence of skeletal benthic faunas in background sediments. Gravity-generated

mudflows descended the slope, entraining organisms (including infauna) and transporting

them to downslope environments where they were rapidly entombed by the settling mudflow.

19

Supplementary Table 1. Community data matrix of the Qingjiang biota used for rarefaction

analyses. The data for Walcott Quarry, Marble Canyon and Chengjiang (Mafang) are derived

from Caron et al. (2014, table S1) (28).

Genera Number Genera Number Genera Number

⑤ Sinocylindra 86 ③ Ambrolinevitus * 8 ④ New Arthropod D 2

⑤ Megaspirellus 23 ③ Burithes yunnanensis * 2 ④ New Arthropod E 2

⑤ New Algae A 85 ③ New Hyolith A 4 ④ New Arthropod F 1

⑤ New Algae B 515 ③ New Hyolith B * 210 ④ New Arthropod G 1

⑤ New Algae C 23 ③ New Hyolith C * 22 ④ New Arthropod H 1

② New Algae D 4 ③ Indete Hyolithida 5 ④ Indete Arthropoda 34

⑤ New Algae E 12 ② Heliomedusa 2 ④ Amplectobelua 3

⑤ New Algae F 3 ① Lingulella 1 ④ Hurdia 3

② Leptomitus 113 ① Diandongia 2 ④ New Radiodont A 3

② Choia 88 ① New Brachipod A * 1 ④ New Radiodont B 1

② Leptomitella 3 ① Indete Brachipoda * 1 ③ New Lobopodian A 4

② Saetaspongia 30 ③ New Mollusc A * 1 ③ New Lobopodian B 1

② Halichondrites 60 ④ Burgessia 2 ① Palaeoscolecid 5

② Crumillospongia 8 ④ Naraoia 123 ① Corynetis 3

② Hazelia 2 ④ Misszhouia 22 ① Selkirkia? 3

② Paraleptomitella 2 ④ New Naraoiid A 26 ① New Priapulid A 2

② Quadrolominiella 2 ④ New Naraoiid B 12 ① New Priapulid B 2

② New Sponge A 2 ④ New Naraoiid C 1 ① New Priapulid C 1

② New Sponge B 7 ④ Mollisonia 1 ① Indete Priapulida 16

② New Sponge C 2 ④ Leanchiolia 125 ① New Kinorhynch A 396

② New Sponge D 10 ④ Alaclcomenaeus 23 ① New Kinorhynch B 9

② New Sponge E 2 ④ New Leachioliid A 10 ① New Kinorhynch C 5

② New Sponge F 2 ④ Redlichia * 19 ④ Vetulia 2

② Indete# Porifera 33 ④ Ptychopariida * 65 ④ New Vetulicolian A 17

② Xianguangia sinica 1495 ④ Estaingia * 14 ④ New Vetulicolian B 1

② New Cnidarian A 6 ④ Kuanyangnaspis * 1 ⑤ Eldonia 3

② New Cnidarian B 4 ④ New Trilobite A * 2 ④ Yunanozoon 3

② New Cnidarian C 28 ④ New Trilobite B * 24 ④ Banffia 8

⑤ New Cnidarian D 59 ④ Liangshanella 41 ② ?Echinodermata 10

⑤ New Cnidarian E 51 ④ Isoxys 25 ④ ?Enteropneustra 5

⑤ New Cnidarian F 27 ④ Branchiocaris 9 ② ?Urochordata 26

⑤ New Cnidarian G 2 ④ Tsunyiella 12 ④ ?Vertebrata 3

⑤ New Cnidarian H 2 ④ Sunella 10 New Problematic A 32

⑤ New Ctenophore A 4 ④ Combinivalvula 1 New Problematic B 34

⑤ New Ctenophore B 4 ④ New Bivalved A 2 New Problematic C 31

② Dinomischus 2 ④ New Arthropod A 1 New Problematic D 13

② Allonnia * 3 ④ New Arthropod B 1 New Problematic E 4

② Archotuba * 22 ④ New Arthropod C 1 New Problematic F 3

Note：① Infauna ② Sessile epibenthos ③ Vagile epibenthos ④ Nekton/Nektobenthos ⑤ Pelagic; *No soft bodied tissue found;

Indetermined taxa excluded in rarefaction analysis.

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