Topic
Thylacocephala
About: Thylacocephala is a research topic. Over the lifetime, 24 publications have been published within this topic receiving 573 citations.
Papers
Book•
1 Jan 1991
TL;DR: In this article, a phylogenetic analysis of metazoan phyla and the placement of fossil problematica is presented, based on sequences of the 28S ribosomal RNA.
Abstract: 1. Origin of metazoans: a phylogeny deducted from sequences of the 28S ribosomal RNA R. Christen, A. Ratto, A. Baroin, R. Persasso, K. Grell and A. Adoutte 2. Major factors in the rapidity and extent of the metazoan radiation during the Proterozoic-Phanerozoic transition J. W. Valentine 3. Divergence and persistence of highly ranked taxa R. R. Strathmann 4. Problematical taxa: a problem for biology or biologists? S. Conway Morris 5. Metazoan evolution around the Precambrian-Cambrian transition J. Bergstroem 6. Cladistic analysis of metazoan phyla and the placement of fossil problematica F. R. Schram 7. Is fossil evidence consistent with traditional views of the early metazoan phylogeny? J. Dzik 8. Lower Cambrian lagerstatte from Chengjiang, Yunnan, China: insights for reconstructing early Metazoan life Chen Jun-Yuan and D. D. Erdtmann 9. Middle Cambrian biotic diversity: examples from four Utah Lagerstatten L. A. Robison 10. Extant 'problematica' within or near the Metazoa G. Haszprunar, R. M. Riefer and P. Schuchert 11. On the origin of the Bilateria: traditional views and recent altneratuve concepts R. M. Rieger, G. Hazprunar and P. Schuchert 12. Problematic reef-building spongers R. A. Wood 13. Beach and laboratory experiments with the jellyfish Aurelia, and remarks on some fossil 'medusoid' traces D. L. Bruton 14. Early Cambrian medusiform fossils from Chengjiang, Yannan, China Sun Weiguo 15. The enigma of conulariid affinities L. E. Babcock 16. Evolutionary affinities of conulariids H. Van Iten 17. Functional morphology of the Class Helcionelloida nov., and the early evolution of the Molusca J. S. Peel 18. The arthropods of the Lower Cambrian Chengjiang fauna, with relationships and evolutionary significance Hou Xian-Guang and J. Bergstroem 16. Early Palaeozoic arthropods and problems of arthropod phylogeny with some notes on taxa of doubtful affinities A. M. Simonetta and L. Delle Cave 17. New observations on the thylacocephala (Arthropoda, Crustacea) A. Alessandrello, P. Arduini, G. Pinna and G. Teruzzi 18. Fossil Acarida: contribution of palaeontolgical data to acarid evolutionary history F. Bernini 19. Are Protura really insects R. Dallai 20. The Tully Monster and a new approach to analyzing problematica J. S. Beall 21. Problematica-incertae sedis E. L. Yochelson.
193 citations
TL;DR: Tuzoia was a large bivalved arthropod with a nonmineralized domelike carapace strengthened by prominent pointed features and often flanked by a lateral ridge bearing a spiny frill as discussed by the authors.
Abstract: The morphology of Tuzoia is reinterpreted in the light of abundant new specimens from the Middle Cambrian Burgess Shale (British Columbia, Canada) and Kaili (Guizhou, China) Lagerstatten. Tuzoia was a very large (up to 180 mm long) bivalved arthropod with a nonmineralized domelike carapace strengthened by prominent pointed features and often flanked by a lateral ridge bearing a spiny frill. The reticulate pattern of Tuzoia is comparable with that of present-day crustaceans (e.g., myodocope ostracods) and is interpreted as a structural compromise between exoskeletal lightness and high resistance to mechanical stress. Tuzoia had a pair of large, stalked, spherical, possibly compound eyes facing forward. Flagella-like antennae protruded through the anterior notch. No other appendages are known except possible filamentous setae underlying the carapace. Tuzoia typically occurs as laterally (lc) or dorsoventrally (dvc) compacted carapaces or single valves. Each type (lc or dvc) emphasizes particular aspects of the morphology (e.g., spiny lateral ridge, ventral margin) that were often interpreted as specific differences by previous authors. A revision of Tuzoia validates only 7 of the 23 named species. Tuzoia is placed tentatively within a group of large bivalved arthropods along with Isoxys and the possible ancestors of Thylacocephala (Lower Cambrian–Upper Cretaceous). In the Middle Cambrian, Tuzoia occurs across Laurentia, South and North China, and the Perigondwanan area (Bohemia) within a relatively narrow subtropical belt, indicating a high dispersal capability and possible latitudinal control on its distribution. Functional morphology, taphonomy, and the distributional pattern indicate that Tuzoia was a free-swimming arthropod.
67 citations
Journal Article•
TL;DR: Zhenghecaris shankouensis gen. et sp. as discussed by the authors is one of the largest bivalved arthropods of the Lower Cambrian Maotianshan Shale fauna.
Abstract: Zhenghecaris shankouensis gen. et sp. nov. is one of the largest “bivalved” arthropods of the Lower Cambrian Maotianshan Shale fauna. Its non−mineralized carapace was dome−like, laterally compressed, armed with rostral features, and probably enclosed the entire body of the animal. Zhenghecaris was provided with elliptical stalked lateral eyes. The carapace design, external ornament and visual organs of Zhenghecaris suggest affinities with the Thylacocephala, an ex-tinct (Lower Silurian to Upper Cretaceous) group of enigmatic arthropods whose origins remain poorly understood. The bivalved arthropods Isoxys and Tuzoia (Lower and Middle Cambrian) are two other potential thylacocephalan candidates making this group of arthropods a possible new component of Cambrian marine communities. Zhenghecaris, Isoxys, and Tuzoia are interpreted as nektonic animals that probably inhabited the lower level of the water column in shallow shelf settings at depths of perhaps 100–150mor less. Their feeding mode either in the water column (e.g., mesozooplankton) or on the substrate (e.g., small epibenthos, detritus) is uncertain, although some of these arthropods were possibly mid−water predators (e.g., Isoxys with raptorial appendages).
65 citations
TL;DR: Converging lines of evidence from depositional environment and modern analogues indicate that this arthropod fauna probably inhabited a deep water setting most probably exceeding 200 m (= bathyal zone) under dysphotic or aphotic conditions, and sheds new light on the deep-sea colonisation by animal communities in the Mesozoic.
Abstract: The La Voulte Lagerstatte is remarkable for its unique soft-bodied fauna (e.g., worms, coleoid squids) and its exceptionally preserved arthropods mainly found in small sideritic concretions. This arthropod fauna includes 30 different species assigned to the crustaceans, the thylacocephalans and the pycnogonids. Crustaceans are the most diversified group with 23 species distributed in a dozen families. Quantitative analyses based on 388 nodules reveals four dominant groups: (i) the enigmatic thylacocephalan arthropods (33%), (ii) the Solenoceridae shrimps (22%), (iii) the Coleiidae crustaceans (15%), and (iv) the Penaeidae shrimps (10%). Converging lines of evidence from depositional environment and modern analogues, indicate that this arthropod fauna probably inhabited a deep water setting most probably exceeding 200 m (= bathyal zone) under dysphotic or aphotic conditions. This new set of data sheds new light on the deep-sea colonisation by animal communities in the Mesozoic.
61 citations
TL;DR: An intensive study of a collection of arthropods from the Cretaceous of Lebanon reveals that these forms belong to the problematical arthropod class Thylacocephala, and unique characters of at least the genus Protozoea are the numerous ‘pits’ covering the entire carapace, elongated anterior rostral and posterior spines, and a dorsal hinge indicative of a truly bivalved carapaces.
Abstract: An intensive study of a collection of arthropods from the Cretaceous of Lebanon, formerly referred to as stomatopod larvae, reveals that these forms belong to the problematical arthropod class Thylacocephala. The species Protozoea hilgendorfi, P. damesi, and Pseuderichthus cretaceus display defining thylacocephalan characters such as a carapace enclosing the entire body bearing a large anterior optic notch; three pairs of large, raptorial appendages; and a posterior battery of small swimming limbs associated with muscle segments. Unique characters of at least the genus Protozoea are the numerous ‘pits’ covering the entire carapace, elongated anterior rostral and posterior spines, and a dorsal hinge indicative of a truly bivalved carapace. We note several anatomical curiosities that provide some insight into the anatomy, ecology and phylogenetic relationships of these and other thylacocephalan species. Structures on the carapace surface of thylacocephalans may represent sensory organs comparable to the receptors seen on thecostracan crustaceans. The affinities of the three species described are still not entirely clear, but a phylogenetic analysis of the entire group may resolve this.
52 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 3 |
| 2020 | 1 |
| 2019 | 1 |
| 2018 | 1 |
| 2017 | 3 |
| 2015 | 1 |