A new type of loriciferan larva (Shira larva) from the deep sea of Shatsky Rise,Pacific Ocean

Loricifera is a phylum of minute animals that live exclusively in marine sediments. A total of 33 species have been described so far in this phylum; however, several more are already known from preliminary observations. Loriciferans are characterised by a complex life cycle, which involves a succession of several adult and larval stages. Here, we describe a new type of loriciferan larval stage: the Shira larva. The gross morphology of this larva is generally similar to that of the most prominent larval type of Loricifera, the so-called Higgins larva. However, the Shira larva possesses a number of unique features, namely (1) a single pair of anteroventral setae is present in the most anterior region of the abdomen, (2) the bases of the anteroventral setae are very large and swollen, (3) the thorax and abdomen are thinner than the introvert and (4) the abdominal region is divided into five sub-regions. Accordingly, we described the new species, Tenuiloricus shirayamai gen. nov. et sp. nov. (incertae sedis). The new findings are discussed from a comparative perspective with the Higgins larva as well as with the fossil of a putative loriciferan larval stage from the Middle Cambrian.     

Recent Priapulidae and their Early Cambrian ancestors: comparisons and evolutionary significance

Although priapulid worms form a relatively small phylum in present-day marine environments, they were important animals in Cambrian endobenthic communities. Two Early Cambrian priapulids, namely Xiaoheiqingella peculiaris and Yunnanpriapulus halteroformis nov. gen., nov. sp. from the Maotianshan Shale Lagerstätte of SW China are revised and described. Several key-features of the body plan of Recent Priapulidae are recognized in these two forms: 1) the four-fold body division (introvert, neck, trunk, and caudal appendage); 2) the well-developed introvert armed with ca. 25 longitudinal rows of scalids; 3) the caudal appendage; 4) the pharyngeal teeth arranged in a pentagonal disposition (Xiaoheiqingella); 5) the ventral nerve cord present in Yunnanpriapulus. This morphology indicates close evolutionary relationships with modern priapulids. Xiaoheiqingella and Yunnanpriapulus nov. gen. are tentatively placed within the recent family Priapulidae. The Priapulidae lineage may therefore have a remote origin (Early Cambrian) much older than was previously assumed (Priapulites; Late Carboniferous). The functional morphology of Xiaoheiqingella and Yunnanpriapulus nov. gen. suggests that these two worms were chiefly carnivorous with possible occasional mud-eating habits.     

New material of the oldest known scalidophoran animal Eopriapulites sphinx

Eopriapulites sphinx is the oldest known scalidophoran animal and so far the only cycloneuralian body fossil from the Cambrian Fortunian Stage. The hexaradial symmetry exhibited by the arrangement of its pharyngeal teeth, coronal scalids and introvert scalids expand our knowledge on the early evolution of cycloneuralians. The holotype and only specimen is a fragment with the proboscis and the anterior trunk part preserved, but the posterior trunk part is missing. Here, we report three-dimensionally phosphatized worm trunk fragments from the same locality and horizon yielding E. sphinx. They are regarded as conspecific with E. sphinx based on co-occurrence and identical annulations, and provide key information on the trunk morphology. E. sphinx is completely reconstructed here as a long vermiform animal with densely annulated trunk and no caudal outgrowths. An updated phylogenetic analysis supports that E. sphinx is a stem-lineage derivative of Scalidophora and also indicates that the hexaradial symmetry of Eopriapulites might have evolved independently from that of Nematoida.     

Occurrence of the Lower Cambrian anemone-style trace fossils in the Zabuk Formation (Mardin–Derik,SE Turkey)

The Zabuk Formation of the Derik Group exposed over much of south-eastern Turkey presents a succession composed of shallow marine and fluvial siliciclastic sedimentary rocks. The Lower Cambrian assemblages containing abundant anemone-style trace fossils are known from most major palaeocontinents such as Laurentia, Baltica, and Gondwana. These have possible affinities with semi-infaunal dwelling anemones on siliciclastic mid-latitude shelves of West Gondwana in early Fortunian deposits. Among them is Bergaueria, characterized by plug-shaped burrows as exemplified by Bergaueria perata, that is, a characteristic trace fossil of the Cambrian globally.     

Loricate choanoflagellates (Acanthoecida) from warm water seas. VII. Calotheca Thomsen and Moestrup,Stephanacantha Thomsen and Syndetophyllum Thomsen and Moestrup

The tectiform loricate choanoflagellate genera Calotheca, Stephanacantha and Syndetophyllum have all been first described from warm water habitats and share the presence of flattened and often elaborate costal strips in the lorica. The current reinvestigation does confirm both the widespread occurrence of these taxa within the global warm water belt, and largely corroborates the established genus and species matrix. We describe here Stephanacantha oceanica sp. nov. which closely resembles S. campaniformis, and transfer Parvicorbicula zigzag to the genus Stephanacantha, despite differences in costal strip morphology, but based on a complete agreement in lorica constructional details.     

Wood of Tapirira (Anacardiaceae) from the paleogene Clarno Formation of Oregon

A new species of fossil wood, Tapirira clarnoensis, is described from a probable late Eocene deposit in the Clarno Formation of Oregon known locally as the Nut Beds. The wood represents, to the knowledge of the writer, the earliest occurrence of Tapirira in the fossil record and the only occurrence of the genus outside its present neutropical range of distribution.     

Ancient butterfly-ant symbiosis: direct evidence from Dominican amber

Although symbiotic association with ants is pervasive in the butterfly families Lycaenidae and Riodinidae the age of these symbioses has never been estimated explicitly. Here we report the first known fossil riodinid caterpillar. This fossil can be dated minimally between 15 and 20 Ma old, and confidently placed in the extant genus Theope. Differing little from modern day Theope, this fossil from Dominican amber provides direct evidence that secretory and acoustical organs used by modern caterpillars to mediate symbioses with ants have been highly developed at least since the Miocene. This fossil therefore becomes the point of reference for future studies using molecular clock methods for dating these symbioses within the riodinid butterflies. Modern evidence, and the abundance of dolichoderine ants in Dominican amber (now extinct in the West Indies) imply that specialized symbiotic relationships between Theope caterpillars and these ants were likely in existence at least 15 Ma ago. The current distribution of neotropical riodinid butterfly and ant faunas indicates the extinction in the West Indies of at least two unrelated taxa that formed a tightly linked symbiotic association, which persisted to the present elsewhere. <br>     

湖北宜昌乔家坪村寒武系水井沱组海绵动物化石群

海绵动物是最原始的动物门类之一,其演化史对于研究多细胞动物的起源和早期演化至关重要.现有的化石记录显示,水体较深的贫氧环境可能是寒武纪早期海绵动物演化的重要场所之一.前人在贵州、湖南、安徽等多地的斜坡至盆地相黑色页岩中已经报道了数个海绵化石群.在这样的环境中,由于水动力作用较弱,海绵骨架结构容易得到原位保存.湖北宜昌秭...     

The evolutionary relationships of the earliest known cycloneuralians and a new record from the Cambrian Fortunian of South China

The Cambrian Fortunian Kuanchuanpu Formation and coeval strata in southern Shaanxi and northern Sichuan Provinces contain phosphatic carbonate that has yielded unambiguous body fossils of cycloneuralians. To date, six genera and species as well as nine indeterminate forms have been reported, and they provided information on the earliest known cycloneuralians and ecdysozoans. Among them, an indeterminate form is critical for understanding the evolution of the Fortunian cycloneuralians, and here I formally name it as Xinliscolex intermedius n. gen. n. sp. It has a series of at least seven longitudinal spinose sclerites on the dorsal side, and sensory structures such as pores and tubules distributed randomly among the annuli. The trunk end has two pairs of bilaterally arranged caudal spines. Micro-CT analysis reveals the preservation of a pharynx with inverted introvert with internally hollow scalids, an esophagus, midgut and hindgut, and a terminal anus. The digestive tract of Xinliscolex intermedius resembles that of modern priapulids, implying that the earliest known cycloneuralians have evolved a relatively derived digestive system, and this lays a foundation for their further diversification and evolution.     

Anabarella australis (Mollusca, Helcionelloida) from the Lower Cambrian of Greenland

The Early Cambrian helcionelloid mollusc Anabarella australis is described from North-East Greenland, representing the second occurrence of the species outside of Australia. Other Australian molluscs of this age are known from many localities including North China, Siberia, Altai, Transbaikalia, southern Kazakhstan, Mongolia, eastern Germany and Spain. These records, supported now by A. australis, demonstrate the close proximity of continents in the Early Cambrian.     

Occurrence ofByronia Matthew andSphenothallus Hall in the Lower Cambrian of China

Rare phosphatic tubular fossils from the Lower-Middle Cambrian Kaili Formation of Guizhou Province, southern China were originally identified as non-calcified algae or ‘worms’ (ScoleciellusLiu). Re-examination of these fossils indicates that specimens identified as non-calcified algae areSphenothallus taijiangensis n. sp., while specimens identified asScoleciellus belong toByronia natus (Liu).Sphenothallus taijiangensis andByronia natus from Lower Cambrian strata in the Kaili Formation are the oldest known representatives of their genera. In addition,B. natus (Liu) is the only known species ofByronia with the exception ofB. annulata Matthew (Middle Cambrian, British Columbia). CambrovitusMao et al., a tubular fossil from Middle Cambrian strata in the Kaili Formation, originally was classified as a hyolithid. However, the discovery of a nearly complete specimen possessing an apical attachment disk shows thatCambrovitus, likeByronia andSphenothallus, probably was a thecate cnidarian polyp.     

New fossils of ascomycetous anamorphic fungi from Baltic amber

Three new fossils of saprotrophic fungi are presented and described from Baltic amber, dated to Eocene epoch (Paleogene, upper to mid-Eocene). All belong to Ascomycota and are represented by hyphae as well as asexual reproduction structures allowing to assign them to present genera, respectively Periconia, Penicillium and Scopulariopsis. These material provide both the first and the oldest known fossil record of the mentioned taxa, making these data valuable for the knowledge about the evolutionary history of the Ascomycota.     

A first report of Sphenothallus Hall, 1847 in the Cambrian of Variscan Europe

Ten specimens of two phosphatic fossils have been recently discovered in lower and middle portions of Middle Cambrian Jince Formation in the Czech Republic. They are attributed to the genus Sphenothallus Hall, 1847 and described as two separate species; comparatively small conchs are described as S. kozaki sp. nov., the much larger specimens characterized by its smooth and partly flexible organo-phosphatic walls of shell are determined as ?S. kordulei sp. nov. Sphenothallus is known to range from Cambrian to Permian and accommodates numerous species. However, its Cambrian distribution is considerably restricted. Generally rare specimens have been described from Lower to Middle Cambrian of Laurentia and from the Lower Cambrian of Gondwana and peri-Gondwana. The new record of Sphenothallus from the Jince Biota represents a notable extension of their geographic range.     

Extraordinary fossils reveal the nature of Cambrian life: a commentary on Whittington (1975) ‘The enigmatic animal Opabinia regalis,Middle Cambrian,Burgess Shale,British Columbia’

Harry Whittington''s 1975 monograph on Opabinia was the first to highlight how some of the Burgess Shale animals differ markedly from those that populate today''s oceans. Categorized by Stephen J. Gould as a ‘weird wonder’ (Wonderful life, 1989) Opabinia, together with other unusual Burgess Shale fossils, stimulated ongoing debates about the early evolution of the major animal groups and the nature of the Cambrian explosion. The subsequent discovery of a number of other exceptionally preserved fossil faunas of Cambrian and early Ordovician age has significantly augmented the information available on this critical interval in the history of life. Although Opabinia initially defied assignment to any group of modern animals, it is now interpreted as lying below anomalocaridids on the stem leading to the living arthropods. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.     

Benthic primary producers in exceptionally preserved Cambrian biotas of North China

Strata situated within the South China Craton host several key Cambrian macroalgal assemblages, including those of the Chengjiang, Kaili, and Tsinghsutung Lagerstätte. In this report, Cambrian macroalgae are described for the first time from the North China Craton, an area that, during the early Paleozoic, was not contiguous with the South China Craton. The material collected from the Mantou Formation and overlying Zhangxia Formation (Miaolingian Series) in Shandong Province is preserved as carbonaceous compressions and includes abundant simple tubular forms. These fall into two groupings on the basis of size and have characteristics broadly comparable to Fuxianospira gyrata and Sinocylindra yunnanensis, both of which are well-known from the Chengjiang biota and may represent simple siphonous green algae. Additional material includes irregular circular to oval films referable to Morania fragmenta and a tuft-like form superficially similar to Marpolia spissa, taxa with possible cyanophyte affinities described initially on the basis of material from the Burgess Shale but also known from the Cambrian of South China. The material is typical of the “Cambrian Flora” and provides further support for the cosmopolitan distribution of this noncalcified macroalgal flora at low latitude settings during the Cambrian.     

Wandel der Vorstellungen von der Frühevolution der Mollusken,besonders der Gastropoda und Cephalopoda

The ancestors of the molluscs are still unknown. Arguments in favour of flatworm-relationship are just as valid as those proposing segmented annelid-like worms as their closest relatives. The earliest molluscs lived before the onset of the Cambrian; but only at the end of this period the now existing classes of conchifers made their first appearance. Early and Middle Cambrian molluscan fossils are problematic. The hyoliths, for example, show relations to such fossils asSalterella andVolborthella, while closest living relatives can be found among tube-building annelids. Scars produced by tissue attached to the shell are of no use in the reconstruction of molluscan phylogeny, but a very useful tool in the analysis of the function regarding the body in interaction with its shell. The ontogenesis of the shell and muscles attached to it in recentFissurella (archaeogastropod) is presented as an example. Well known ontogenies in recent molluscs can aid to the reconstruction of fossils, demonstrated by some fossil gastropods. The interaction of soft and hard tissues, the function and structure of the shell of recent molluscs enables us to interpret the fossil forms, as for example the Lower Devonian coleoid cephalopods from the Hunsrück Schiefer. Reconstruction of the course of evolution is only possible, if information on living molluscs is integrated into historical data provided by the fossils.     

Lower Ovetian (Lower Cambrian) trilobites and biostratigraphy of the Pedroche Formation (Sierra de Córdoba, southern Spain)

The low Lower Cambrian rocks from the Sierra de Córdoba, which consist of well exposed mixed facies and abundant fossil assemblages showing long stratigraphic ranges throughout the Pedroche Formation, represent one of the best successions of this age in Europe. The fossil assemblages include diverse Ovetian archaeocyaths, trilobites, small shelly fossils, calcimicrobia, trace fossils and stromatolites. Trilobites are still poorly known, and thus they are the main objective of this work. The trilobites studied originate from three sections. At the Arroyo de Pedroche 1 section, cf. Bigotinella and Bigotinabivallata are replaced towards the top by Lemdadellalinaresae, Lemdadellaperejoni sp. nov. and, finally, by Eoredlichia cf. ovetensis. At the Arroyo de Pedroche 2 section, Lemdadellalinaresae is replaced by Lemdadellaperejoni sp. nov. and Eoredlichia cf. ovetensis, while at the Puente de Hierro section Lemdadellalinaresae, L. aff. linaresae and Serraniaverae occur together. These new biostratigraphic data confirm that the Pedroche Formation, originally defined as a repetitive sequence of four members, contains only two members. The new trilobite discoveries permit the first tentative correlation between the Ovetian of southern Spain and Lower Cambrian strata from the High Atlas (Morocco), Siberia, Antarctica and Carteret (France).     

A new fossil wood from the highly diverse early Eocene equatorial forest of Gujarat (western India)

During the early Eocene (～55–52 Ma), when the Indian subcontinent relished equatorial climatic conditions, lignite was deposited along its north western margin. Lignite mines of northwestern India have proved to be an outstanding resource for palaeoenvironmental information. The Vastan lignite mine of the early Eocene age situated near Surat district (Gujarat) is one of the well-dated and fossiliferous lignite mines in western India. A fossil wood, retrieved from this mine, is systematically described and shows a strong resemblance to the modern genus Chisocheton of the family Meliaceae. Plant fossils are the best source to reconstruct the palaeoenvironment of any region, and here a luxurious, highly diverse tropical evergreen forest is interpreted in and around the fossil locality in contrast to the tropical thorn forest of the present day. This early Eocene highly diverse equatorial forest, once covered a significant portion of the Indian subcontinent, is now restricted in fringes known as Western Ghats in south India attesting to changes in climate.