The life and death of torquirhynchia inconstans (brachiopoda,upper jurassic) in England

Torquirhynchia inconstans, a rhynchonellid brachiopod, shows a curious asymmetric commissure. This is interpreted as an adaptation to life in tidal environments. Type of preservation, growth line, and size frequency analysis indicate that the population analyzed consist of dominantly mature individuals, which by analogy with recent brachiopod populations is a primary feature of the original population, and not due to selective destruction, selective transport, or selective predation of smaller individuals. The possible functions of the asymmetry of Torquirhynchia inconstans are considered, and it is concluded that the brachiopod was adapted to life in tidal environments, a conclusion supported by sedimentological evidence. Asymmetric brachiopods are considered to have developed from colonies of partly asymmetric, variable brachiopods by selection of extreme variants.     

Brachiopod ecology in mid-Palaezoic sediments near Khenifra,Morocco

The modes of occurrence of a Silurian atrypid and a Devonian rhynchonellid near Khenifra in central Morocco are described. They are both thought to have lived on isolated shoals within muddy basins. A substrate for brachiopod attachment in each case was provided by lime-secreting algae. Most of the Devonian rhynchonellids are preserved in olistostromes, within Carboniferous shales, but some are in situ. The rhynchonellid, which is identified as Eoperegrinella, is thought to have taken over the ecological niche previously occupied by the atrypid, identified as Dubaria, during Devonian times. Descendent rhynchonellids of the same group in the Mesozoic lived in a similar way.     

Morphology of gametes of mollusks, echinoderms, and brachiopods in systematics and phylogeny

The morphology of eggs and sperm of echinoderms, mollusks, and brachiopods was studied and compared. The gametes of inarticulate brachiopods (two classes Lingulata and Craniata and two subphyla Linguliformea and Craniaformea) are shown to have significant morphological differences from those of articulate brachiopods (extant class Rhynchonellata, subphylum Rhynchonelliformea). Inarticulate brachiopods have similar sperm morphology to that of primitive brachiopods, bivalves and some polychaetes that have external fertilization. Sperm morphology of articulate brachiopods is similar to that of echinoderms, which are considered to be typical deuterostomate invertebrates. This similarity supports an early deviation of lophophore-bearing animals from Bilateria, before this lineage branched into Protostomia and Deuterostomia. Similar gamete morphology in Lingulata and Craniata supports the view that inarticulate brachiopods should be retained as a supraclass taxon for comparison with other Lophotrochozoa, in particular with phoronids, bryozoans, and mollusks. Based on the new data on the gamete morphology in inarticulate brachiopods, we propose the name Lingulophyles with the type genus Lingula, and for articulate brachiopods Coptothyrophyles with the type genus Coptothyris.     

Halorina cryptica nov. ichnogen., nov. ichnosp., mass-occurrence of Upper Triassic crustacean microcoprolites from neptunian dikes and sills cutting the Dachstein-type carbonate platform and their paleoenvironmental significance (Northern Apuseni Mountains,Romania)

The new crustacean microcoprolite Halorina cryptica nov. ichnogen., nov. ichnosp., is reported from cryptic cavities cutting the Upper Triassic (Carnian to lower Rhaetian) Dachstein-type limestones from the Northern Apuseni Mountains, Romania. The new ichnotaxon is extremely abundant in cavities, neptunian dikes and sills filled with red ferruginous carbonate sediment. The associated microfauna consists of ostracods and rare foraminifera. The microfacies is represented by bioclastic coprolite-bearing wackestone-packstone to grainstone. The red ferruginous carbonate fillings are strongly bioturbated. The neptunian sill located at the top of the studied section contains a rich ichnofauna associated with brachiopod accumulations. It is dominated by the dimerelloid rhynchonellid Halorella, indicating a late Norian-early Rhaetian age. Although neptunian dikes and sills are rather common in the Dachstein-type carbonate platform that extended on the northwestern Tethyan margin, we report here the first record of mass-occurrence of crustacean microcoprolites in neptunian dikes and sills filled with red carbonate sediments of marine origin. They are interpreted here as cryptic cavities with specific palaeoenvironmental features (e.g., lack of light, abundant nutrients, intensive microbial activity) where crustacean arthropods thrived.     

Marine ostracodes from Paleogene hydrocarbon seep deposits in Washington State,USA and their ecological structure

Invertebrate fossils described from ancient hydrocarbon seep deposits represent diverse groups, e.g., brachiopods, mollusks, decapod crustaceans, worm tubes, and rare echinoderms, but the fossil record of ostracodes from hydrocarbon seep deposits is still very limited, making their ecology and evolutionary history still little known. We found fossil ostracodes in eight Eocene to Oligocene hydrocarbon seep deposits in the Humptulips, Lincoln Creek, Makah, and Pysht formations in western Washington State, USA. They represent eleven taxa belonging to genera found in a wide range of shelf to slope habitats: Acanthocythereis, Loxoconcha?, Cytherella, Cytheropteron, Macropyxis?, Krithe, Paracosta, Pontocythere?, Propontocypris, Palmoconcha, and Neonesidea? Acanthocythereis acroreticulata from one late Oligocene seep deposit in the Lincoln Creek Formation is the oldest and northernmost record for this species. The hydrocarbon seep ostracode faunas from Washington appear to be benthos-dominated, showing the same ecological structure and pattern of phylogenetic relatedness as ostracodes from Miocene and Quaternary seep sediments from Italy and off Ireland. We suggest that the benthos-dominated structure has been stable for ostracodes in hydrocarbon seep environments and/or has a higher preservation potential than the nektobenthos-dominated structure.     

Ecological interactions on macroevolutionary time scales: clams and brachiopods are more than ships that pass in the night

Competition among organisms has ecological and evolutionary consequences. However, whether the consequences of competition are manifested and measureable on macroevolutionary time scales is equivocal. Marine bivalves and brachiopods have overlapping niches such that competition for food and space may occur. Moreover, there is a long‐standing debate over whether bivalves outcompeted brachiopods evolutionarily, because brachiopod diversity declined through time while bivalve diversity increased. To answer this question, we estimate the origination and extinction dynamics of fossil marine bivalve and brachiopod genera from the Ordovician through to the Recent while simultaneously accounting for incomplete sampling. Then, using stochastic differential equations, we assess statistical relationships among diversification and sampling dynamics of brachiopods and bivalves and five paleoenvironmental proxies. None of these potential environmental drivers had any detectable influence on brachiopod or bivalve diversification. In contrast, elevated bivalve extinction rates causally increased brachiopod origination rates, suggesting that bivalves have suppressed brachiopod evolution.     

Brachiopods from cryptic coral reef habitats in the northern Red Sea

In contrast to the Palaeozoic to Jurassic fossil record, modern tropical and subtropical shallow-water brachiopods are typically small-sized and mostly restricted to cryptic habitats in coral reefs, but information on microhabitat-composition is scant. At Dahab, northern Red Sea, living brachiopods of the genus Argyrotheca were only detected on massively encrusted coral colonies attached to encrusting foraminifers and coralline red algae. Three samples from autochthonous sediments underneath coral colonies are comparatively rich in the brachiopod genera Megerlia and Argyrotheca, and additionally show low numbers of Novocrania and Thecidellina. Based on a coarse-grain analysis including more than 16,000 components >1 mm, these brachiopod shells co-occur with skeletal components of 11 higher taxa. Decapods, fixosessile foraminifers, molluscs, scleractinians, and coralline red algae clearly dominate the assemblages. Brachiopods in this study always contribute less than 2% to the sediment composition. This confirms previous results that even in brachiopod habitats the contribution of brachiopod shells to the total sediment composition is almost negligible. Our study indicates that brachiopods co-occur with pteriomorph bivalves and other epifauna in the cryptic habitats with limited space for encrusters or epibionts on the undersides of scleractinians and it tentatively supports the hypothesis of brachiopods preferring habitats with low grazing pressure, because shelly components of grazers (polyplacophorans and regular echinoids) are rare in our samples.     

Epizoans on late Ordovician brachiopods from Southeastern Indiana

The frequency of epizoans (cornulitids, inarticulate brachiopods, bryozoans, solitary and colonial rugosan corals) on over 8000 specimens of articulate brachiopods (four strophomenids, five orthids, one rhynchonellid) was calculated for four stratigraphic horizons in the Dillsboro Formation of southeastern Indiana. Frequency of shells encrusted correlates significantly with the surface area of the valves. Punctae in brachiopod shells (Onniella meeki) may have deterred larval settlement of epizoans. Coarse ribbing on articulates deterred encrustation by the inarticulate brachiopod. The horn coral shows a preference for attachment to the anterior of Hiscobeccus capax. Bryozoans show a preference for the incurrent lateral margins of inferred living hosts, suggesting rheotropic behavior by settling larvae. Inarticulate brachiopods are concentrated around the sloping commissure of the brachial valve of strophomenids, suggesting geotropic behavior and/or selective survival of settling larvae. Inarticulates deterred overgrowth by bryozoans. High frequencies of encrustations of the medial region of pedicle valves of orthids and strophomenids probably reflect post‐mortem encrustations. Alternating intervals of slow sediment accumulation punctuated by tropical storms and rapid shell burial may account for the high frequency of shells with either their entire surface veneered or only a very small area encrusted by bryozoans.     

An unusual brachiopod assemblage in a Late Jurassic (Kimmeridgian) stromatactis mud-mound of the Eastern Carpathians (Hăghimaş Mountains), Romania

An unusual fossil assemblage dominated by superabundant rhynchonellid brachiopods in a stromatactis mud-mound is recorded from the Hăghimaş Mountains (Eastern Carpathians), Romania. The mound mainly consists of bioclastic wackestones to packstones with a very rich macrofauna including crinoids, sponges, juvenile ammonites, and echinoids. The brachiopods represent a low-diversity but high-abundance association, dominated by the rhynchonellids Lacunosella and Septaliphoria. The taphonomical features of the fossil assemblage indicate an autochthonous fauna, with successive generations of brachiopods in life position and complete well-preserved individuals in different growth stage alongside an accessory population of crinoids and sponges. Brachiopod-brachiopod endosymbiotic life strategy is documented for the first time from a post-Paleozoic brachiopod assemblage. The mound reveals abundant stromatactis, filled by radiaxial fibrous or drusy calcite cement and internal polymud sediments. This is the first Late Jurassic (Kimmeridgian) stromatactis mud-mound identified in the Eastern Carpathians.     

Intense drilling in the Carboniferous brachiopod Cardiarina cordata Cooper, 1956

The brachiopod Cardiarina cordata, collected from a Late Pennsylvanian (Virgilian) limestone unit in Grapevine Canyon (Sacramento Mts., New Mexico), reveals frequent drillings: 32.7% (n = 400) of these small, invariably articulated specimens (<2 mm size) display small (<0.2 mm), round often beveled holes that are typically single and penetrate one valve of an articulated shell. The observed drilling frequency is comparable with frequencies observed in the Late Mesozoic and Cenozoic. The drilling organism displayed high valve and site selectivity, although the exact nature of the biotic interaction recorded by drill holes (parasitism vs. predation) cannot be established. In addition, prey/host size may have been an important factor in the selection of prey/host taxa by the predator/parasite. These results suggest that drilling interactions occasionally occurred at high (Cenozoic-like) frequencies in the Paleozoic. However, such anomalously high frequencies may have been restricted to small prey/host with small drill holes. Small drillings in C. cordata, and other Paleozoic brachiopods, may record a different guild of predators/parasites than the larger, but less common, drill holes previously documented for Paleozoic brachiopods, echinoderms, and mollusks.     

Large extinctions of articulate brachiopods in the paleozoic and their ecological and evolutionary consequences

The largest Paleozoic extinctions of articulate brachiopods occurred at the Frasnian—Famennian boundary in the Late Devonian and at the Permian—Triassic boundary. Both extinctions affected taxa of all levels, including orders, but differed in scale, course, and ecological and evolutionary consequences. The Frasnian—Famennian extinction event was selective and evolutionary activity after the crisis varied in different orders. However, in the Early Carboniferous, the brachiopod diversity was mostly restored in comparison with the Devonian maximum. In particular groups, preadaptation played a role in changes in diversity and reconstruction of communities. The brachiopod composition at this boundary changed sharply. The extinction event at the end of Permian was global and accompanied by changes in the biota. Later, in the Meso-Cenozoic, the brachiopod diversity was not restored, and bivalves acquired primary importance in various bottom communities of different sea zones where Paleozoic brachiopods previously dominated. Extinction of brachiopods at this boundary was long and gradual. The symptoms of the ecological crisis in the development of Permian brachiopods are recognized beginning from the Roadian Age, which was probably the onset of this crisis.     

Thick brachiopod shell concentrations from prodelta and siliciclastic ramp in a Tortonian Atlantic–Mediterranean strait (Miocene, Guadix Basin, southern Spain)

Carbonate production by brachiopods in shallow-water habitats is generally expected to be not sufficiently high and temporally persistent to allow them to form very thick and densely packed shell concentrations. The formation of thick brachiopod concentrations requires long-term persistence of populations with high density of individuals, and such circumstances are assumed to be rare especially during the Cenozoic. However, here we show that the large-sized brachiopod Terebratula terebratula, the most common species in benthic assemblages with epifaunal bivalves and irregular echinoids, formed several decameter- to meter-thick, densely packed concentrations in shallow siliciclastic, high-energy environments, in a seaway connecting the Atlantic Ocean with the Mediterranean Sea during the Latest Tortonian (Late Miocene, Guadix Basin, southern Spain). This brachiopod formed (1) meter-scale, thick, parautochthonous concentrations in a prodelta setting and (2) thin, mainly allochthonous, tide- and storm-reworked concentrations in megaripples and dunes. The abundance of brachiopods at the spatial scale of the Guadix Basin seems to be mainly related to intermediate levels of sedimentation rate and current velocity because abundance and thickness of shell concentrations decline both (1) in onshore direction towards delta foresets with high sedimentation rate generated by debris flows and (2) in offshore direction with increasing levels of tide- and storm-induced substrate instability. Although brachiopods in dune and megaripple deposits are more fragmented, disarticulated, and sorted, and have a higher pedicle/brachial valve ratio than in prodelta deposits, taphonomic damage is still relatively high in prodelta deposits. Terebratula terebratula thus formed thick concentrations in spite of that disintegration processes were relatively intense along the whole depositional gradient. Therefore, population dynamic of this species was probably characterized by production maxima that were comparable to some Cenozoic molluscs in terms of their productivity potential to form thick shell concentrations in shallow subtidal environments. We suggest that temporal changes in brachiopod carbonate production have a significant spatial and phylogenetic component because multiple large-sized species of the family Terebratulidae, which underwent radiation during the Cenozoic, attained high abundances and formed shell concentrations in temperate regions.     

THE COMPOSITION AND STRUCTURE OF LOWER SILURIAN MARINE COMMUNITIES

Five benthic communities occupied the shelf regions of the British Isles, Norway, and North America in Upper Llandovery times. The communities are listed below in order of increasing distance from shore.

• 1 The Lingula Community is the least diverse; it has both infaunal elements, including a protobranch, and two lingulids, and epifaunal elements, including a rhynchonellid, a pterioid, and a cornulitid. A restricted and protected near-shore environment, such as a bay or estuary, is postulated.
• 2 The Eocoelia Community shares elements in common with the former community, but is more diverse and is dominated by epifaunal forms; the many small pedunculate brachiopods probably lived attached to the large leptostrophiid brachiopod.
• 3 The Pentamerus Community is dominated by this genus which lived free and upright on the bottom; smaller pedunculate brachiopods probably attached to this large neighbor.
• 4 The Costistricklandia Community was similar in structure to the former community with the many small pedunculate brachiopods being attached to the large Costistricklandia.
• 5 The Clorinda Community is the most diverse, with a great variety of small brachiopods which were probably able to attach to small objects in this quiet off-shore environment, or to some moderately sized brachiopods, such as Clorinda and Cyrtia, which apparently lived free on the bottom.

The brachiopod dominated communities of the Silurian clearly inhabited the ‘level bottom’, an area now occupied mainly by infaunal forms. The main attachment surfaces for the epifaunal elements of the Silurian communities were disarticulated, convex-upward shells.     

Ecophenotypic asymmetry in the middle Danian brachiopod Obliquorhynchia flustracea caused by adaptation to attachment on the coral Dendrophyllia candelabrum

The rhynchonellid brachiopod Obliquorhynchia flustracea from the middle Danian (Paleocene) cool‐water coral mounds of the Faxe Formation, Denmark, exhibits commissural asymmetry, a rare feature in articulate brachiopods. It has been much discussed whether the underlying reasons for this asymmetry were species specific caused by pedicle attachment in the limited space between the branches of the scleractinian Dendrophyllia candelabrum. The two species are always found together, and the brachiopod is essentially missing outside facies characterized by D. candelabrum. Based on morphological analyses and statistical tests, we suggest that ecophenotypic variation is the main reason for the variability in the external shell morphology and development of commissural asymmetry. Conditions such as sexual dimorphism and defects can be dismissed as a facilitating reason of phenotypic variation. This is a rare case where it is possible to directly link commissural asymmetry to mode of attachment on a specific host.     

Cenozoic Methane-Seep Faunas of the Caribbean Region

We report new examples of Cenozoic cold-seep communities from Colombia, Cuba, the Dominican Republic, Trinidad, and Venezuela, and attempt to improve the stratigraphic dating of Cenozoic Caribbean seep communities using strontium isotope stratigraphy. Two seep faunas are distinguished in Barbados: the late Eocene mudstone-hosted ‘Joes River fauna’ consists mainly of large lucinid bivalves and tall abyssochrysoid gastropods, and the early Miocene carbonate-hosted ‘Bath Cliffs fauna’ containing the vesicomyid Pleurophopsis, the mytilid Bathymodiolus and small gastropods. Two new Oligocene seep communities from the Sinú River basin in Colombia consist of lucinid bivalves including Elongatolucina, thyasirid and solemyid bivalves, and Pleurophopsis. A new early Miocene seep community from Cuba includes Pleurophopsis and the large lucinid Meganodontia. Strontium isotope stratigraphy suggests an Eocene age for the Cuban Elmira asphalt mine seep community, making it the oldest in the Caribbean region. A new basal Pliocene seep fauna from the Dominican Republic is characterized by the large lucinid Anodontia (Pegophysema). In Trinidad we distinguish two types of seep faunas: the mudstone-hosted Godineau River fauna consisting mainly of lucinid bivalves, and the limestone-hosted Freeman’s Bay fauna consisting chiefly of Pleurophopsis, Bathymodiolus, and small gastropods; they are all dated as late Miocene. Four new seep communities of Oligocene to Miocene age are reported from Venezuela. They consist mainly of large globular lucinid bivalves including Meganodontia, and moderately sized vesicomyid bivalves. After the late Miocene many large and typical ‘Cenozoic’ lucinid genera disappeared from the Caribbean seeps and are today known only from the central Indo-Pacific Ocean. We speculate that the increasingly oligotrophic conditions in the Caribbean Sea after the closure of the Isthmus of Panama in the Pliocene may have been unfavorable for such large lucinids because they are only facultative chemosymbiotic and need to derive a significant proportion of their nutrition from suspended organic matter.     

Lopingian (Late Permian) brachiopods around the Wuchiapingian-Changhsingian boundary at the Meishan Sections C and D, Changxing, South China

The strata below the defined Wuchiapingian-Changhsingian boundary GSSP are mostly covered and obscured by faulting at the Meishan Section D. Therefore, it is very difficult to collect fossils there. After an intensive excavation at Meishan Section C, a diverse fauna based on high-resolution biostratigraphy comprising brachiopods, ammonoids, conodonts, fusulinids and small foraminifers were found. Among these fossils, brachiopods are the most dominant. Eleven species of 10 genera based on more than 1300 specimens are identified. This brachiopod fauna is of late Wuchiapingian-Changhsingian of Lopingian (Late Permian) in age as well constrained by the associated ammonoid Pseudogastrioceras sp., Jinjiangoceras and Konglingites sp., the fusulinid Palaeofusulina and the conodont lineage from C. longicuspidata to C. wangi. In terms of the changes of brachiopod fauna composition around Wuchiapingian-Changhsingian boundary, it clearly indicates a continuous transgression from the upper part of the Lungtan Formation to the lower part of the Changhsing Formation. A new species, Neochonetes (Huangichonetes) meishanensis, is described and some other species are discussed based on the new collection from Meishan Sections C and D.     

A palaeoecological study of the Upper Coralline Limestone, Terebratula-Aphelesia bed (miocene,malta) based on bryozoan growth-form studies and brachiopod distributions

A prominent bed, containing brachiopods and ectoproct bryozoans, is widely distributed within the Maltese Islands, being associated with a coralline algal rhodolite bioherm. This bed provides a useful stratigraphic marker horizon at the base of the Upper Coralline Limestone Formation.Samples taken from the bed at localities in Malta and Gozo have been examined and their contained biodata studied. Distribution analysis of the bryozoan growth-forms present has permitted recognition of four assemblages, dominated by cellariform, vinculariiform, encrusters, and cellariform and vinculariiform bryozoan growth-forms, respectively. Morphological variations and distributions of brachiopods contained within the samples were also examined and these were compared with the bryozoan growth-form distributions previously obtained. An interpretation of the palaeoecology of the four common brachiopod species, Terebratula terebratula, Aphelesia bipartita, Argyrotheca cf. cordata and Megathiris decollata, is offered partly on the basis of present-day brachiopod ecology but mainly on the basis of information gained for the bryozoans. Interpretations of the palaeoecology of several other common invertebrate genera, also based on the bryozoan growth-form distributions, are also presented.     

Metabolic dominance of bivalves predates brachiopod diversity decline by more than 150 million years

Brachiopods and bivalves feed in similar ways and have occupied the same environments through geological time, but brachiopods were far more diverse and abundant in the Palaeozoic whereas bivalves dominate the post-Palaeozoic, suggesting a transition in ecological dominance 250 Ma. However, diversity and abundance data alone may not adequately describe key changes in ecosystem function, such as metabolic activity. Here, we use newly compiled body size data for 6066 genera of bivalves and brachiopods to calculate metabolic rates and revisit this question from the perspective of energy use, finding that bivalves already accounted for a larger share of metabolic activity in Palaeozoic oceans. We also find that the metabolic activity of bivalves has increased by more than two orders of magnitude over this interval, whereas brachiopod metabolic activity has declined by more than 50%. Consequently, the increase in bivalve energy metabolism must have occurred via the acquisition of new food resources rather than through the displacement of brachiopods. The canonical view of a mid-Phanerozoic transition from brachiopod to bivalve dominance results from a focus on taxonomic diversity and numerical abundance as measures of ecological importance. From a metabolic perspective, the oceans have always belonged to the clams.     

Mitochondrial COI sequences of brachiopods: genetic code shared with protostomes and limits of utility for phylogenetic reconstruction

A 1230-bp region of the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA of each of 16 brachiopod species, representing all five living orders, was amplified by polymerase chain reaction and sequenced. Pairwise comparisons of sequence differences plotted against divergence times estimated from the brachiopod fossil record revealed that, although there are considerable variations in the expected substitution rate among different lineages, amino acid substitutions of the COI sequences may largely become saturated in 100 Ma, due mostly to multiple substitutions at the same site. Coinciding with this result, phylogenetic analysis indicated low bootstrap values for nodes corresponding to divergence events that occurred before 100 Ma, suggesting that COI sequences are suitable only for inference of phylogenetic events subsequent to the Mesozoic. Examination of brachiopod codons corresponding to invariant amino acids in the COI of various other animals suggest the nonuniversal codon relationships UGA = Trp, AUA = Met, AAA/G = Lys, and AGA/G = Ser. These are identical to those in mollusks, annelids, and arthropods, consistent with the conclusion that brachiopods are protostomes, as indicated by previous molecular analyses.     

Early Cambrian organophosphatic brachiopods from the Xinji Formation,at Shuiyu section,Shanxi Province,North China

Abundant and diverse small shelly fossils have been reported from Cambrian Series 2 in North China, but the co-occurring brachiopods are still poorly known. Herein, we describe seven genera, five species and two undetermined species of organophosphatic brachiopods including one new genus and new species from the lower Cambrian Xinji Formation at Shuiyu section, located on the southern margin of North China Platform. The brachiopod assemblage comprises one mickwitziid (stem group brachiopoda), Paramickwitzia boreussinaensis n. gen. n. sp., a paterinide, Askepasma toddense Laurie, 1986, an acrotretoid, Eohadrotreta cf. zhenbaensis Li and Holmer, 2004, a botsfordiid, Schizopholis yorkensis (Holmer and Ushatinskaya in Gravestock et al., 2001) and three linguloids, Spinobolus sp., Eodicellomus cf. elkaniiformis Holmer and Ushatinskaya in Gravestock et al., 2001 and Eoobolus sp. This brachiopod assemblage suggests a late Age 3 to early Age 4 for the Xinji Formation and reveals a remarkably strong connection with coeval faunas from East Gondwana, particularly the Hawker Group in South Australia. The high degree of similarity (even at species level) further supports a close palaeogeographic position between the North China Platform and Australian East Gondwana during the early Cambrian as indicated by small shelly fossil data.