Trilobites are extinct marine arthropods that have been useful for exploring topics in Paleozoic paleoecology and evolution. Malformations in trilobites-injuries, developmental anomalies, and pathologies-offer valuable insights into trilobite biology, behavior, and interactions. This study represents the fourth installment in a series documenting malformed trilobites in North American institutions and focuses on the Yale Peabody Museum invertebrate paleontology collection. Four malformed specimens, representing Ogygiocarella debuchii (Brongniart, 1822), Arctinurus boltoni (Bigsby, 1825), and Coronura aspectans (Conrad, 1841) are documented herein. These specimens show evidence for injuries and teratologies, as well as examples that are ambiguous and may represent injuries or teratologies. We also examined the use of reflectance transformation imaging to determine whether this approach could represent a useful alternative to ammonium chloride coating for imaging trilobites. This work enhances the record of trilobite malformations and emphasizes the utility of historically important museum collections in expanding these datasets.

The ubiquitous iron oxides and oxyhydroxides on Mars represent intriguing targets in the search for evidence of past microbial life on the Red Planet. So far, no studies have systematically investigated microbial fossils in fluviolacustrine ferricrete composed entirely of nanophase goethite; thus, our understanding of biosignatures in such deposits is limited. Here, we report exceptionally well-preserved microfossils in laminated nanophase goethite from the Miocene McGraths Flat Lagerstätte, New South Wales, Australia. Using scanning electron microscopy and energy dispersive spectroscopy, we identified a diverse range of fossil morphotypes, including bacteria and fungi. Syngenetic forms embedded in the sedimentary matrix and post-depositional endolithic colonizers were recognized. Our findings establish nanophase goethite as an excellent preservation medium for microfossils, capable of preserving subcellular details across multiple generations of microbial communities, and highlight nanophase goethite as a promising target for future Mars exploration missions.

The Ninmaroo Formation is a thick succession of richly fossiliferous carbonates that straddles the Cambrian (Furongian, Stage 10)- Lower Ordovician (Tremadocian, Tr1) boundary in the vicinity of Black Mountain (Mount Unbunmaroo) in western Queensland. Abundant, relatively coarsely silicified specimens of a plectorthoid brachiopod recovered from the lower Corrie Member of the Ninmaroo Formation type section are taxonomically described as a new species, Apheoorthis talenti n. sp. The stratigraphic level hosting the brachiopods occurs above the first occurrence, but within the biostratigraphic range, of the important age-diagnostic conodont species Cordylodus lindstromi which represents the upper Furongian Series (Stage 10) globally. In the Australian context, the new brachiopod occurs in the basal Warendan regional stage. Brachiopods are rare in Furongian rocks from Australia, making A. talenti n. sp. one of very few Cambrian Stage 10 rhynchonelliform brachiopods described from Australia. (c) 2025 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Locating new fossil sites with exceptional soft-tissue preservation is vital for addressing taphonomic bias and accurately reconstructing the fossil record. McGraths Flat, a Miocene rainforest lake Konservat-Lagerstatte, uniquely preserves nanometre-scale soft-tissue structures in laminated Fe-oxyhydroxide (goethite) or 'ferricrete'. However, constraints on the source of Fe, depositional conditions, and mechanisms that drove the exceptional soft-tissue preservation were lacking. Here, we demonstrate that warm, seasonally wet rainforest conditions generated acidic soils and transported dissolved Fe(II) from weathering basaltic bedrock into an oxbow lake. Fe(III)-oxyhydroxide precipitation then drove fossil burial and mineralization. Our findings suggest that 'McGraths Flat-type' fossil preservation may be common and could represent an untapped record of life on land.

BACKGROUND:Corcoraniidae is a rare and understudied family of lower Paleozoic euarthropods that are important for understanding early chelicerate evolution. However, the diversity, morphology, and distribution of this group remain poorly resolved, particularly during the late Cambrian. RESULTS:Here, we describe a new corcoraniid from the late Cambrian (Furongian) Rivière-du-Loup Formation of Quebec, Canada. The distinctive morphology of this specimen warrants erection of a new genus and species, Magnicornaspis garwoodi gen. et sp. nov. This new taxon expands the morphological disparity in Corcoraniidae and suggests that a shift in location of large cephalic spines arose within older members of the clade. The presence of a corcoraniid within the Rivière-du-Loup Formation provides a crucial data point within the "Furongian Gap" suggesting that perceived biodiversity declines may be an artifact of sampling bias rather than anoxia-driven extinction. CONCLUSIONS:This material highlights the potential for exceptional soft-bodied preservation within deeper-water lithofacies and warrants renewed investigation of the Rivière-du-Loup Formation. The deposit has a high probability of representing a new Furongian Konservat-Lagerstätte that will present important insight into late Cambrian biodiversity and the evolutionary history of early arthropods.

Nineteen trilobite species, including 10 new taxa, are reported from the lower Cambrian (Series 2, Stage 4, upper Ordian) First Discovery Limestone Member of the Coonigan Formation in the Koonenberry Belt of far western New South Wales, Australia. Previous reports of the brachiopod taxa Micromitra nerranubawu and Eothele granulata, along with the trilobites Redlichia and Onaraspis, support the unit being assigned to the lower Micromitra nerranubawu Zone. This is further confirmed by the trilobite fauna described herein, which shares its greatest similarity to age equivalent strata in the Amadeus Basin of the Northern Territory; common taxa include Olenoides percivali sp. nov., Pagetia silicunda (= Pagetia sp. cf. P. quebecensis), Xystridura fracta (=Xystridura gayladia), Gunnia fava, and Xingrenaspis krusei sp. nov. Other species level similarities include assemblages found in the upper Ordian and lower Templetonian sequences of the Daly, Georgina, Ord and Wiso basins. New species introduced include: Redlichia holmesi sp. nov., Onaraspis cymbricensis sp. nov., Dinesus shergoldi sp. nov., Dinesus whitehousei sp. nov., Olenoides lawrenceorum sp. nov., Olenoides percivali sp. nov., Onchocephalus? warrisi sp. nov., Xingrenaspis krusei sp. nov., Changqingia andersonorum sp. nov., and Solenoparia gnaltaensis sp. nov.

Crustacean cuticle in the fossil record provides insight into their preservation potential, including instances of exceptional preservation. The elemental composition of cuticular remains permit these taphonomic pathways to be explored. This study uses energy dispersive X-ray spectroscopy to examine the exoskeletal elemental composition of five crustacean taxa-Bombur complicatus, Caryocaris curvilata, Mecochirus sp., Sculda syriaca, and Tealliocaris woodwardi-ranging from the Ordovician to the Cretaceous. We also compare the composition of these fossil forms to modern species to explore changes within the group. We document calcium and phosphorus as dominant elements across most fossil specimens. As modern crustaceans use calcium carbonate extensively, this result suggests one of two explanations: either the original exoskeleton of these extinct crustaceans was composed of both calcium carbonate and phosphate or its fossil composition was the result of diagenetic phosphatization in anoxic environments. The higher levels of phosphorus in fossil taxa compared with modern taxa highlights the current lack of easy criteria to determine whether the mineralogical component of a fossil exoskeleton has been diagenetically altered. To this end, we present future directions for addressing this complication. Furthermore, Mecochirus sp. cuticle is predominantly composed of carbon, demonstrating an alternate preservational pathway that cannot be distinguished from the other examples based on a visual examination under visible light alone. Its preservation is likely linked to modification of organic compounds. Our findings and discussions underscore a complex interplay of environmental and geochemical factors in crustacean fossilization, uncover novel examples of preservational routes, and illustrate how energy dispersive X-ray spectroscopy (EDS) elucidates exoskeletal preservation.

The Rookery Limestone Member is exposed in a small area on 'The Rookery', southeast of Cobar in central NSW. An Early Devonian, either Lochkovian or Pragian, age for the stratum was previously determined based on the brachiopod, trilobite and conodont faunas preserved. Microvertebrate remains include scales of acanthodians Nostovicina guangxiensis and Trundlelepis cervicostulata; scales and dermal bone fragments possibly of the placoderm Connemarraspis; and scales, dermal bone fragments, and possible gnathal plates of a romundinid placoderm. Alternatively, the gnathal plates could be from the stem osteichthyan Lophosteus incrementus. This fauna indicates a late Lochkovian age based on the stratigraphic distribution of these taxa elsewhere in NSW, and accords with dating suggested by the conodont taxa from the same samples.

This report documents the conodonts recovered from the Andersons Tank Limestone Member (new name) and calcareous siltstone lenses within the Scropes Range Formation and from the Kandie Tank Limestone within the Kayrunnera Group of the central-southern Koonenberry Belt in far western New South Wales, Australia. Among 18 identifiable conodont species are two new species, Paltodus simplex sp. nov. and Variabiloconus delicatus sp. nov. The conodonts confirm that the age of the Kandie Tank Limestone extends from the latest Cambrian (Cordylodus proavus Biozone) to Early Ordovician (Chosonodina herfurthi Biozone), partly contemporaneous with the Andersons Tank Limestone Member that ranges from the latest Cambrian Cordylodus proavus Biozone to possibly earliest Ordovician (Cordylodus lindstromi Biozone). Occurrence of the index species Iapetognathus fluctivagus and Iapetonudus ibexensis in the middle part of the Kandie Tank Limestone provides direct correlation to the base of the Ordovician System defined at the Green Point section in western Newfoundland of North America, and to sections in Asia and South America. These new data have significantly improved our current understanding of the Ordovician biostratigraphy in the region and more broadly the geological history and evolution of the eastern Gondwana margin during the early Paleozoic. We provide detailed morphological comparison and formal designation of the lectotypes for the four species (I. fluctivagus, Iapetognathus jilinensis, Iapetognathus landingi and I. ibexensis) critical for defining and globally correlating the basal Ordovician.Zhen Y.Y.* [yong-yi.zhen@regional.nsw.gov.au] and I.G. Percival [ianpercival1952@gmail.com], Geological Survey of New South Wales, W.B. Clarke Geoscience Center, 947-953 Londonderry Road, Londonderry New South Wales 2753, Australia;P.M. Smith [Patrick.Smith@australian.museum], Paleontology Department, Australian Museum Research Institute, 1 William Street, Sydney New Sout Wales 2010, Australia, and School of Natural Sciences, 18 Wally's Walk, Ground Floor, Macquarie University, Sydney New South Wales 2109, Australia;B.D. Webby [bwebby25@gmail.com], School of Geosciences, University of Sydney, New South Wales 2006, Australia.

A new pedunculate cirripede (barnacle) is described from the Lower Cretaceous Allaru Mudstone near Richmond in central Queensland, Australia. Isolated plates of a related species, Zeugmatolepas australis, are known from the Upper Cretaceous Gingin Chalk of Western Australia, but this material represents the first articulated zeugmatolepads to be reported from the Southern Hemisphere. It comprises remarkably well-preserved remains with numerous specimens found to be almost fully articulated, although laterally compressed. This record further supports a cosmopolitan distribution of the Zeugmatolepadidae. The Allaru Mudstone is interpreted as having been deposited in relatively cool waters (similar to 19 degrees C), under oxic to sub-oxic conditions at less than 100 m depth.John St J. S. Buckeridge* [john.buckeridge@rmit.edu.au], Earth and Oceanic Systems Group, RMIT University, 370 Swanston Street, Melbourne VIC 3001, Australia; Palaeontology Department, Museums Victoria, Carlton, VIC 3001, Australia;Patrick M. Smith [patrick.smith@austmus.gov.au], Palaeontology Department, Australian Museum Research Institute, Sydney, NSW 2010, Australia; School of Natural Sciences, Macquarie University, Sydney, NSW 2109, Australia.

The Australian Cambrian stratigraphic record is one of the most complete for any continent. However, there is a general division, with older Cambrian rocks in South Australia (predominantly Terreneuvian, Stage 2 to Miaolingian, Wuliuan) and younger rocks in northern Australia (mostly latest Series 2, Stage 4 and younger), with minimal stratigraphic overlap. The recently ratified boundary between Cambrian Series 2 and Miaolingian occurs in the interval of overlap between these successions, hence investigation of these levels is a priority. The successions in the southern and eastern parts of the Georgina Basin (Queensland and Northern Territory) underpin the Cambrian biostratigraphy of northern Australia. Therefore, targeted, multi-proxy work on these successions is important for developing a fully resolved Australian Cambrian chronostratigraphy. Here we present new insights into this critical interval via biostratigraphic analysis of the Thorntonia Limestone (shown to span the Cambrian Series 2 - Miaolingian boundary) in three recently drilled core holes near Boulia, Queensland, in the south-eastern Georgina Basin. A diverse fossil fauna (>50 species) is described from these cores, including biostratigraphically important trilobites, agnostids, brachiopods, bradoriids, echinoderms, hyoliths, molluscs, sponges and other small shelly fossils (SSFs). These show affinities with Australian Ordian (late Stage 4) to Templetonian (Wuliuan) faunas, with a potential Floran (early Drumian) interval in the uppermost Thorntonia Limestone. Many SSF taxa recovered from the Thorntonia Limestone show close affinities with other East Gondwanan assemblages from North China and Antarctica in particular, as well as with assemblages from Laurentia, Siberia, South China, Kazakhstan, the Himalaya and West Gondwana.

The Cambrian Series 2-Miaolingian boundary interval in Australia-equivalent to the local Ordian and Templetonian stages-has long been a source of controversy, with a practical and consistent subdivision of this interval proving elusive. Recent ratification of the Miaolingian Series and Wuliuan Stage Global Boundary Stratotype Section and Point (GSSP) in South China, based primarily on the first appearance of the trilobite Oryctocephalus indicus and the coincident Redlichiine-Olenelline Extinction Carbon isotope Excursion (ROECE), highlights the importance of resolving this interval in Australia. In this contribution, we present an updated synthesis of Cambrian Series 2, upper Stage 4-Miaolingian, Wuliuan (Ordian-Templetonian) intervals across Australia, focusing on the reported ranges of small shelly fossils (SSF) and 513C/518O isotope chemostratigraphy, in addition to trilobite and agnostid arthropod occurrences. Results show an underappreciated sequential series of taxon lowest occurrences across this interval. Based on these, we define two new organophosphatic brachiopod biozones: an upper Stage 4 (Ordian) Schizopholis napuru Zone, and an uppermost Stage 4-Wuliuan (upper Ordian-Templetonian) Micromitra nerranubawu Zone. Taxon ranges across these zones are consistent with the Cambrian Series 2-Miaolingian boundary at the Miaolingian/Wuliuan GSSP, allowing direct correlation with South China. Preliminary work in the Australian Stansbury and Georgina basins has revealed the promise of highresolution SSF biostratigraphy coupled with 513C/518O chemostratigraphy in addressing the ongoing issues associated with this interval. It is clear that such multi-proxy studies can assist in locating boundaries and correlating intervals across different Cambrian terranes with a high degree of precision, even when lacking index fossils such as O. indicus. Future work should focus on a systematic program of such studies within this interval, which will greatly assist in resolving correlations both within Australia and globally.

Reassessment of the agnostid and trilobite assemblages originally figured by Bischoff and Prendergast (1987) from the lowest Wagonga Group (herein informally named the "lower formation"), allows for a more precise interpretation of the unit's age which was previously assigned a very approximate range of "Middle" to "Late" Cambrian. The presence of Micragnostus (=Innitagnostus) cf. medius (Shergold, 1980), Onchonotellus cf. kuruktagensis (Zhang,1981), Wuhuia aff. silex Shergold,1980 and an indeterminate species of Pseudorhaptagnostus Lermontova, 1951, correlate with early Iverian assemblages in the Georgina Basin, Queensland, and early Jiangshanian taxa in South China (between the Wentsuia iota-Rhaptagnostus apsis to Peichiashania secunda-Prochuangia glabella trilobite assemblage zones of Australia). The paraconodonts Westergaardodina bohlini Muller, 1959 and Westergaardodina kleva Muller, 1959 further support a Jiangshanian age. The consistent faunal composition across all limestone olistoliths and beds suggests a penecontemporaneous origin, contradicting previous interpretations that the limestones resulted from prolonged erosion of an older carbonate platform. Instead, we propose a dynamic depositional environment on the flanks of a volcanic seamount, with limestone blocks transported via debris flows during volcanic events, analogous to modem deep-sea sedimentation processes. Faunal similarities with the Australian craton suggest proximity of this seamount to the eastern Gondwana margin during the Cambrian.

Malformed trilobites have been documented in deposits ranging from the Cambrian to the Permian. Continued examination of novel malformed specimens provides insight into how trilobites recovered from injuries, experienced genetic abnormalities, and adapted to pathological conditions. This study focuses on trilobites from the Silurian and Devonian of Europe, presenting new records of: (i) a moulting-related injury in Lioharpes venulosus; (ii) genetic malformations in Calymene blumenbachii and Treveropyge sp.; and (iii) a moulting injury or genetic anomaly in Scutellum (Scutellum) pardalios. Additionally, we record evidence of bryozoan growth on a C. blumenbachii specimen. Our findings provide important data for contextualizing the paleobiology of early and middle Paleozoic trilobites, especially related to responses to ecological pressures.

Examples of malformed trilobites are well documented in the fossil record. These specimens are critical for elucidating aspects of trilobite paleoecology, particularly in the context of developmental biology, predation, and pathologies. Ongoing efforts to catalog these malformations within paleontological collections have yielded significant insight into trilobite paleobiology, especially related to posttraumatic recovery and predator-prey interactions. For the third component of this atlas, we identified five examples of malformations across Cambrian (Ogygopsis klotzi, Paradoxides davidis) and Silurian (Glyptambon verrucosus, Lichas breviceps) species within the Field Museum of Natural History collection. These specimens show demonstrable evidence of traumatic injuries, unsuccessful predation, and pathological developments. We investigate the etiologies of these malformations and compare them to other examples of malformed trilobites. Finally, we consider the history of trilobite collections at the Field Museum, exploring the major changes in the collection since the museum was founded.

Marine isopod fossils represent a small component of the crustacean fossil record, contrasting the exceptional modern diversity of marine representatives of Isopoda. Examination of previously documented isopod species therefore presents an opportunity to derive additional paleobiological and taphonomic insight of these rare fossils. Here we consider two clusters of Archaeoniscus brodiei from the Lower Cretaceous (middle to upper Berriasian) Intermarine Member of the Durlston Formation, England. The individuals within the clusters are mostly complete, of similar size ranges, and are preserved on two different bedding planes. After examining these individuals, we illustrate, for the first time, appendages and eyes of A. brodiei. The appendage morphology supports the interpretation of A. brodiei as an isopod adapted to a benthic lifestyle. We propose that isopods from the Durlston Formation follow similar taphonomic pathways to arthropods preserved within plattenkalk-like deposits, resulting in enrichment in calcium carbonate and phosphate. Finally, the clusters reflect gregarious activities that were preserved during hypoxic events brought on by concurrent decay of algal blooms.

A previously unreported dokimocephalid trilobite, Lorrettina waterhousei sp. nov., is described herein from the Iverian (Jiangshanian, Cambrian) upper Goyder Formation, Amadeus Basin, central Australia. This is the first definitive biostratigraphic evidence for rocks of an Iverian (Jiangshanian) age in the Amadeus Basin. Correlation is made with the Chatsworth Limestone (=Gola beds) of the neighbouring Georgina Basin in Australia, as well as internationally to China, based on the generic occurrence. The biostratigraphic age of the unit is also supported by previous carbon isotope chemostratigraphy, further strengthening the interpretation.

The chronostratigraphical scale is a hierarchical scheme that is subdivided into increasingly smaller units, from eonothem down to the level of the substage and beyond. Boundaries of chronostratigraphic intervals typically coincide with individual bioevents. As these intervals become smaller, their geographic utility tends to shrink. Typically, where the original interval is inapplicable, the next highest interval in the scale is used for communication. Where appropriate intervals are unavailable, confusion reigns. A stadial subdivision of the Australian mid-late Cambrian (equivalent to the international Miaolingian and Furongian series) was completed in 1993 with the definition of the Furongian Iverian Stage. One stage, the Ordian, was initially suggested as the lowest stage for what is now the Miaolingian, but should be considered to belong to upper Series 2 of the Cambrian. No older Cambrian stages have been proposed in Australia. Indeed, the base of the Ordian has not been defined, due in part to the incompleteness of Series 2 successions in central and northern Australia. A longstanding impediment to the establishment of lower Cambrian stages in Australia arises from the fact that the entire Australian stadial scheme for the Miaolingian and Furongian series was established in the cratonic basins of central-northern Australia, whereas the lower Cambrian is best developed in separate South Australian basins. With the rapid increase in knowledge of the biostratigraphic successions in the South Australian lower Cambrian (Terreneuvian and Series 2) over the last three decades, the time seems ripe for the establishment of such a stadial subdivision. This will require careful correlation between the mostly Terreneuvian and Series 2 succession in South Australia and the mostly Miaolingian-Furongian succession in central and northern Australia. Taxa that can be used for such a stadial subdivision include trilobites, organophosphatic brachiopods, archaeocyaths, small shelly fossils, molluscs and acritarchs, as each has provided the basis of zonations in the South Australian successions.John R. Laurie [john.r.laurie@gmail.com], Geoscience Australia, Symonston Australian Capital Territory 2601, Australia, and School of Natural Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia. Peter D. Kruse [archaeo.kruse@gmail.com], South Australian Museum, Adelaide South Australia 5000, Australia. Glen A. Brock [glenn.brock@mq.edu.au], School of Natural Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia. James D. Holmes [jamesholmes83@gmail.com], Palaeoscience Research Centre, University of New England, Armidale New South Wales 2351, Australia. James B. Jago [Jim.Jago@unisa.edu.au], University of South Australia-STEM, Mawson Lakes, SA 5095, Australia, and South Australian Museum, Adelaide, South Australia 5000, Australia. Marissa J. Betts [Marissa.Betts@une.edu.au], Palaeoscience Research Centre/LLUNE, University of New England, Armidale New South Wales 2351, Australia. John R. Paterson [jpater20@une.edu.au], Palaeoscience Research Centre, University of New England, Armidale New South Wales 2351, Australia. Patrick M. Smith [Patrick.Smith@austmus.gov.au], Australian Museum Research Institute, Sydney New South Wales 2010, Australia, and School of Natural Sciences, Macquarie University, North Ryde New South Wales 2109, Australia.

Mantis shrimp (Stomatopoda) are extant, marine, predatory arthropods, but these malacostracan pancrustaceans are also occasionally preserved in fossil assemblages, particularly in Carboniferous and Cretaceous deposits. Carboniferous species fall into two suborders-Palaeostomatopodea and Archaeostomatopodea-and represent the ancestral forms that gave rise to modern lineages. Herein, we describe hitherto unknown specimens belonging to the archaeostomatopod genus Tyrannophontes from the Pennsylvanian-aged Wea Shale Member, eastern Nebraska. We explore the preservation of these fossils using scanning electron microscopy and energy dispersive X-ray spectroscopy. These approaches reveal additional morphological characteristics, including unique appendicular data, such as the earliest occurrence of biramous gilled appendages in Stomatopoda. We suggest that further examination of black shales will likely uncover novel records of these rare pancrustaceans.