Chapter 33 Neoproterozoic glaciogenic diamictites of the Tarim Block, NW China

<p>Neoproterozoic glaciogenic outcrops are mostly limited to the southwestern and northwestern margins of the Tarim basin and the Tianshan Mountains. Only two glaciogenic diamictites are recorded in the Neoproterozoic successions from the Tielikeli and Aksu-Wusi areas of the Tarim basin. The lower diamictite from the Polong Formation in the Tielikeli area is <em>c.</em> 800 m thick. The upper diamictite in the area is very thin (Yutang diamictite, 10 m; Yulmeinak diamictite, 51 m). In contrast to the Tarim basin, the Neoproterozoic successions along the northern margin of the Tarim Block in the Tianshan Mountains record three or four glaciogenic diamictites, which are well developed and crop out in the Qurugtagh area. Although the glaciogenic nature of the oldest Beiyixi diamictite remains questionable, all other diamictites (Altungol, Tereeken and Hankalchough) exhibit distinct glaciogenic sedimentary features. SHRIMP zircon U–Pb dating demonstrate that the Bayisi diamictite was deposited between 740±7 Ma and 725±10 Ma, the Altungol and Tereeken diamictites between 725±10 Ma and 615±6 Ma, respectively, and the Hankalchough diamictite between 615±6 Ma and <em>c.</em> 542 Ma. Carbonates atop the Altungol, Tereeken and Hankalchough diamictites show distinct C-isotopic values that are typical for those recorded in ‘cap carbonates’ on other continents. The striking similarity between the cap carbonate of the Tereeken and Marinoan-age Nantuo diamictites further support a 635 Ma ‘Marinoan’ age for the Tereeken glaciation. Unlike the 582 Ma Gaskiers glaciations of Newfoundland, the Hankalchough diamictite is possibly <551 Ma, as suggested by C-isotope chemostratigraphy and biostratigraphy, indicating that post-Marinoan glaciations on different continents may be diachronous. </p

<i>Innovatiocaris</i>, a complete radiodont from the early Cambrian Chengjiang Lagerstätte and its implications for the phylogeny of Radiodonta

Character list for phylogenetic analysis

<i>Innovatiocaris</i>, a complete radiodont from the early Cambrian Chengjiang Lagerstätte and its implications for the phylogeny of Radiodonta

Supplementary figures S1–S8

<i>Innovatiocaris</i>, a complete radiodont from the early Cambrian Chengjiang Lagerstätte and its implications for the phylogeny of Radiodonta

Phylogenetic data matrix 1

<i>Innovatiocaris</i>, a complete radiodont from the early Cambrian Chengjiang Lagerstätte and its implications for the phylogeny of Radiodonta

Phylogenetic data matrix 2

Morphology of diverse radiodontan head sclerites from the early Cambrian Chengjiang Lagerstätte, south-west China

<p>Recorded in exceptionally preserved Lagerstätten, the radiodontans (including anomalocaridids) are cosmopolitan, soft-bodied, stem-group euarthropods that inhabited Palaeozoic seas. They are notable for their unique morphology, peculiar ecology and basal position in euarthropod evolution. The early Cambrian Chengjiang Lagerstätte has yielded some of the oldest radiodontans, including three unquestionable taxa – <i>Anomalocaris saron</i> Hou <i>et al</i>., 1995, <i>Amplectobelua symbrachiata</i> Hou <i>et al</i>., 1995 and <i>Lyrarapax unguispinus</i> Cong <i>et al</i>., 2014 – based on articulated specimens. However, recent discoveries of the Burgess Shale <i>Hurdia</i> Walcott, 1912 and the Fezouata <i>Aegirocassis benmoulae</i> Van Roy <i>et al</i>., 2015 highlight the presence of another radiodontan group (Hurdiidae) characterized by a tripartite head sclerite complex consisting of one central element and a pair of lateral elements. Here, we describe six morphotypes of possible hurdiid head sclerite elements from the Chengjiang Lagerstätte, some of which are closely associated with other typical radiodontan body parts. These, recognized as central elements, include two new species of the same new genus, <i>Tauricornicaris latizonae</i> gen. et sp. nov. and <i>T</i>. <i>oxygonae</i> gen. et sp. nov., and a former bivalved euarthropod, <i>Zhenghecaris shankouensis</i> Vannier <i>et al</i>., 2006. Another three unnamed sclerite elements are identified as lateral elements. These sclerite elements from Chengjiang provide detailed anatomy, such as mammillary tubercles and soft-tissue reticulate structure, to help understand the morphology and biology of all hurdiid head sclerites. A common single dorsal plate in <i>Anomalocaris saron</i> and <i>Amplectobelua symbrachiata</i> is confirmed. Although the morphologically diverse central and lateral elements of the Hurdiidae and the conserved dorsal plate of the Anomalocarididae + Amplectobeluidae reflect a major distinction in radiodontan body plans, they share a fundamental structure of double layers of cuticle. The Chengjiang specimens not only clarify the morphology and biology of the radiodontan head sclerites in general, but also illuminate the diversity and disparity of radiodontans in their early evolutionary history.</p> <p><a href="http://zoobank.org/urn:lsid:zoobank.org:pub:urn:lsid:zoobank.org:pub:D0590390-A85A-493A-8529-B2DF64D91169" target="_blank">http://zoobank.org/urn:lsid:zoobank.org:pub:D0590390-A85A-493A-8529-B2DF64D91169</a></p

A new Cambrian frondose organism: ‘Ediacaran survivor’ or convergent evolution?

Supplementary Figures S1–S

MOESM1 of Fossils from South China redefine the ancestral euarthropod body plan

Additional file 1 Figure S1. Anatomical comparison between Sklerolibyon maomima gen. et sp. nov. and Fortiforceps foliosa. a, b, Sklerolibyon maomima gen. et sp. nov. NIGPAS 169962, holotype, from Mafang. a, counterpart (negative imprint), with posterior end missing, shown here after applying inversion of light patterns, in order to show the positive and natural ornamentation. See also Fig. 1d. b, part (positive) with anterior section missing. Inset is Fig. 4a. c, YKLP 11350, paratype, close-up of the anterior region showing limb arrangement; note occasional overlap of endopods from both sides (double arrows). d, e, f, Fortiforceps foliosa. d, e, NIGPAS 169954, from Mafang. d, whole body. Insets are e, Fig. 3a and Fig. 4b, as indicated. e, close-up of endopod, showing a likely heptopodomerous condition. See also d. f, NIGPAS 169955, from Mafang, whole body; arrowheads point to partially phosphatized filamentous structures at the base of trunk limbs. All pictures taken in non-polarized light and dry. Scale bars: 1 mm (a, b), 2 mm (c, d). Figure S2. Segmentation patterns in Jianfengia multisegmentalis. a, b, CPS 1611, from Dapotou. a, Whole body, reconstructed from graphically adding the counterpart (posterior end) to the part (anterior end). b, Close-up of the cephalon, showing great appendages and both pairs of biramous cephalic limbs, from both left and right sides of the animal. c, NIGPAS 169958, from Mafang, whole body. d, CJHMD 0022, from Heimadi, whole body. e, CJHMD 0021, from Heimadi, whole body. All pictures taken in non-polarized light and dry. Scale bar: 1 mm. Figure S3. Morphological details in Jianfengia multisegmentalis. NIGPAS 169961, from Jiucun. a, Whole body. b, Close-up of anterior portion of head, showing anterior margin of cephalic shield and anteriormost body morphology. c, Close-up of biramous trunk limbs. d, Close-up of posterior end of body, showing posterior trunk limbs spread out. e-h, Close-ups of trunk sections, from anterior to posterior, showing details of intersegmental articulation. Arrowheads in b point to anterior margin of cephalic shield. All pictures taken in non-polarized light and dry. Scale bars: 1 mm (a, c, d), 0.5 mm (b, e-h). Figure S4. Consensus cladogram of a Bayesian analysis (Mkv + Γ model) of panarthropod relationships. Numbers next to nodes are posterior probabilities

MOESM3 of Fossils from South China redefine the ancestral euarthropod body plan

Additional file 3. List of characters used in our morphological matrix

Table S1. Geochronological constraint on the Cambrian Chengjiang biota, South China

Table S1: Zircon SIMS U–Pb data of 14CJ-2 and 14CJ-3 from Maotianshan Shale, eastern Yunnan Province, South Chin