Palaios最新文献

{"title":"MORPHOTYPE MATTERS: AN EXPERIMENTAL ANALYSIS OF THE MORPHOLOGICAL FIDELITY OF GASTROPOD STEINKERNS","authors":"ERYNN JOHNSON, Miranda MARGULIS-OHNUMA, Thomas J. Smith, Susan H. Butts, Christina Lutz, Derek E.G. Briggs","doi":"10.2110/palo.2023.041","DOIUrl":"https://doi.org/10.2110/palo.2023.041","url":null,"abstract":"\u0000 Gastropods are commonly preserved as steinkerns (internal casts), a mode of fossilization that leads to loss of external morphological features. This loss of information is problematic for taxonomic identification and ecological inference in evaluating assemblages where original shell material is not preserved. We seek to quantify how closely gastropod steinkerns represent the morphology of their original shells. We investigated this relationship experimentally by fabricating steinkerns in silicone from modern gastropod shells and comparing their geometry to that of the shells we used to create them. In addition to recording traces of ornamentation such as ribs and spines, we used a theoretical morphospace framework to evaluate the fidelity of shell-coiling parameters in steinkerns. Our results show that some morphotypes reflect their taxonomic identification more accurately than others, indicating that steinkern fidelity is highly variable. Experimental steinkerns consistently cluster less reliably by morphotype than their original shell counterparts. Additionally, we find that shell thickness is an important factor in determining steinkern fidelity. The fidelity of the high-spired Duplicaria duplicata, for example, is significantly lower than the average value for the morphotypes investigated whereas the fidelity of planispiral Haplotrema concavum and open-coiling Epitonium is significantly higher, a trend related to shell thickness. Thus, taxonomic identification and subsequent analyses, such as community composition, of steinkern assemblages must recognize this differential fidelity to counter preservational biases.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141809178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MEDITERRANEAN IMPRINT ON CORAL DIVERSITY IN THE INCIPIENT RED SEA (BURDIGALIAN, SAUDI ARABIA)","authors":"Chiara Pisapia, G. Vicens, Francesca Benzoni, Hildegard Westphal","doi":"10.2110/palo.2023.025","DOIUrl":"https://doi.org/10.2110/palo.2023.025","url":null,"abstract":"\u0000 Globally, scleractinian coral diversity peaked in the Early Miocene (Burdigalian) and declined afterwards. In contrast to this global trend, scleractinian coral diversity in the Lower to Middle Miocene was low in the Red Sea, which had begun to open in the Oligocene and experienced its first marine incursion in the Burdigalian. Here, we report on coral diversity of reefs assigned to the Burdigalian to Langhian Wadi Waqb Member (Jabal Kibrit Formation) from outcrops exposed in the foothills behind the Red Sea coastline near Umluj, Saudi Arabia. Compared to the global records from the Paleobiology Database and the literature, the fossil record from the Wadi Waqb member suggests a relation of the taxonomic spectrum to the Arabian Gulf and the Mediterranean. No clear relation to the taxonomic spectrum to the Indian Ocean is observed. These faunal differences are consistent with the hypothesis that the young Red Sea was connected to the Arabian Gulf via the Mediterranean through the Gulf of Suez, but there was no connection between the Red Sea and the Indian Ocean because of the Afar mantle plume that uplifted the southern area of the Red Sea rift and blocked direct exchange of marine biota.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141808625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CAMERAL MEMBRANES IN THE PHRAGMOCONES OF JURASSIC AMMONITES","authors":"A. A. Mironenko, Irina A. Smurova","doi":"10.2110/palo.2023.017","DOIUrl":"https://doi.org/10.2110/palo.2023.017","url":null,"abstract":"\u0000 A complex system of three-dimensional cameral membranes is known from the phragmocones of several ammonoid genera—both Paleozoic and Mesozoic. The origin and functions of these membranes remain mysterious, and their study is complicated by the absence of identical structures in modern cephalopods. Current hypotheses about the origin of cameral membranes and other organic structures of the phragmocone are mainly based on the study of Paleozoic, Triassic, and Cretaceous ammonoids. This paper examines the membranes of Subboreal Jurassic ammonites. The spatial arrangement and complexity of these membranes differ from those described earlier. It was previously assumed that three-dimensional membranes only appeared late in ammonoid ontogeny, at the end of the neanic stage. However, in the ammonites studied herein, such membranes are present starting from the second phragmocone chamber. In addition to membranes, we report other initially organic phragmocone structures of Jurassic ammonites: pseudosutures and drag lines. The discovery of a unique structure in the last phragmocone chamber of one specimen, which likely represents a fossilized set of pseudosepta, has led to a new hypothesis, that can explain the formation of all types of membranes and other initially organic phragmocone structures. According to this idea, all types of cameral sheets despite their different shapes, were formed during merging and subsequent dehydration of organic pseudosepta. Pseudosutures and drag lines are imprints of the pseudosepta margins.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141116566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PRESERVATIONAL ANALYSIS OF JURASSIC CLAM SHRIMPS FROM LA MATILDE FORMATION (PATAGONIA, ARGENTINA) BY LIBS AND RAMAN SPECTROSCOPIES","authors":"Victoria C. Jiménez, Mateo D. Monferran, Diego Martin DÍAZ PACE, Guillermo Javier Copello, Roberto Gerardo Pellerano, N. Cabaleri, O. F. Gallego","doi":"10.2110/palo.2023.006","DOIUrl":"https://doi.org/10.2110/palo.2023.006","url":null,"abstract":"\u0000 Preservation of arthropod cuticles is of paramount importance for taphonomic interpretations in which the fossil record of the chitin-protein complex is considered a key molecular signature of the group studied. In this work, different specimens of clam shrimps and their surrounding sedimentary matrix recovered from four localities of the La Matilde Formation (Patagonia, Argentina) were chemically analyzed for the first time by Laser-induced breakdown spectroscopy (LIBS) and RAMAN spectroscopic techniques. The spectral data recorded from the fossils were processed and analyzed through multivariate statistics, including Principal Component Analysis (PCA), Nonmetric Multidimensional Scaling (NMDS), and Analysis of Similarities (ANOSIM). The correlation between the different colorations featured by the specimens and the atomic chemical composition of their carapaces was systematically investigated to gain a better understanding of the fossilization processes together with more detailed interpretations. We found that the carapaces featuring a yellow-brown color exhibited a similar chemical profile with iron predominance, while those with the same color as the sedimentary matrix presented a distinctive composition. Considering the volcanic influence to which the different localities studied and carapaces were exposed, we propose that the clam shrimps from the four localities were preserved in at least three ways, namely, (1) pyritization; (2) admixed preservation; and (3) impression, each with distinctive characteristics of the taphonomic processes involved. Overall, results obtained provide useful information to achieve a more comprehensive knowledge about the taphonomy of fossils in a Jurassic lacustrine paleo-environment, as the La Matilde Formation.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140684632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TENTACULITIDS IN SUBVERTICAL (LIFE) POSITION IN THE MIDDLE DEVONIAN ARKONA FORMATION, SOUTHERN ONTARIO, CANADA","authors":"C. Tsujita, Gordon C. Baird","doi":"10.2110/palo.2023.029","DOIUrl":"https://doi.org/10.2110/palo.2023.029","url":null,"abstract":"\u0000 A horizon of aperture-up, subvertically oriented shells of Tentaculites in the Middle Devonian Arkona Formation (Hamilton Group) near Arkona, Ontario, Canada, is investigated with respect to burial processes, tentaculitid life habits, and associated diagenetic features. Field observations of the horizon in situ confirm previous suspicions that thick-walled tentaculitoids were benthic and oriented aperture-up in life. In this biocoenosis, tentaculitids vary from low-density populations to dense clumps, the latter sometimes showing grid-like arrangements. The mutual spacing of individuals reflects space demands of a feeding apparatus. The limited size range of the shells suggest that tentaculitid colonization event was brief, involving no more than two generational growth cohorts. Sedimentary features associated with the subvertical shells indicate that the seafloor mud inhabited by the tentaculitids was soft, but sufficiently cohesive to preserve microtopographic features, and prone to disturbance by storms. Preservation of their shells in (subvertical) life position necessitated rapid burial (via mud blanketing) without significant scouring. The emanation of sulfidic decay products from the tentaculitid shell apertures led to the local inhibition of later-precipitated calcareous concretionary cement. Preferential erosion of this material resulted in the development of circular pockmarks on concretion surfaces. The concretions themselves formed along a thin zone of alkalinity that developed below the sediment-water interface at the sulfate-methane boundary during a depositional hiatus sometime after the burial of the subvertical tentaculitids. Variations in the vertical positions of radially tilted tentaculitid shells apertures show undulations that, in turn, imply tentaculitids mutually adjusted their growth directions to maximize living space and/or food acquisition.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140686347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AVIAN FORAGING ON AN INTERTIDAL MUDFLAT SUCCESSION IN THE EOCENE TANJUNG FORMATION, ASEM ASEM BASIN, SOUTH KALIMANTAN, INDONESIAN BORNEO","authors":"J. Zonneveld, Y. Zaim, Y. Rizal, A. Aswan, R. Ciochon, T. SMITH, J. Head, P. Wilf, J. Bloch","doi":"10.2110/palo.2023.004","DOIUrl":"https://doi.org/10.2110/palo.2023.004","url":null,"abstract":"\u0000 Moderately diverse trace fossil assemblages occur in the Eocene Tambak Member of the Tanjung Formation, in the Asem Asem Basin on the southern coast of South Kalimantan. These assemblages are fundamental for establishing depositional models and paleoecological reconstructions for southern Kalimantan during the Eocene and contribute substantially to the otherwise poorly documented fossil record of birds in Island Southeast Asia. Extensive forest cover has precluded previous ichnological analyses in the study area. The traces discussed herein were discovered in newly exposed outcrops in the basal part of the Wahana Baratama coal mine, on the Kalimantan coast of the Java Sea.\u0000 The Tambak assemblage includes both vertebrate and invertebrate trace fossils. Invertebrate traces observed in this study include Arenicolites, Cylindrichnus, Diplocraterion, Palaeophycus, Planolites, Psilonichnus, Siphonichnus, Skolithos, Thalassinoides, Taenidium, and Trichichnus. Vertebrate-derived trace fossils include nine avian footprint ichnogenera (Aquatilavipes, Archaeornithipus, Ardeipeda, Aviadactyla, cf. Avipeda, cf. Fuscinapeda, cf. Ludicharadripodiscus, and two unnamed forms). A variety of shallow, circular to cylindrical pits and horizontal, singular to paired horizontal grooves preserved in concave epirelief are interpreted as avian feeding and foraging traces. These traces likely represent the activities of small to medium-sized shorebirds and waterbirds like those of living sandpipers, plovers, cranes, egrets, and herons. The pits and grooves are interpreted as foraging traces and occur interspersed with both avian trackways and invertebrate traces.\u0000 The trace fossils occur preferentially in heterolithic successions with lenticular to flaser bedding, herringbone ripple stratification, and common reactivation surfaces, indicating that the study interval was deposited in a tidally influenced setting. Avian trackways, desiccation cracks, and common rooting indicate that the succession was prone to both subaqueous inundation and periodic subaerial exposure. We infer that the Tambak mixed vertebrate-invertebrate trace fossil association occurred on channel-margin intertidal flats in a tide-influenced estuarine setting. The occurrence of a moderately diverse avian footprint and foraging trace assemblage in the Tambak Member of the Tanjung Formation illustrates that shorebirds and waterbirds have been using wetlands in what is now Kalimantan for their food resources since at least the late Eocene.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140220879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE MICROBIAL “FINGERPRINTS” FROM THE CONTINENTAL LOWER PERMIAN OF POLAND","authors":"Grzegorz Sadlok","doi":"10.2110/palo.2023.018","DOIUrl":"https://doi.org/10.2110/palo.2023.018","url":null,"abstract":"\u0000 Microbes colonize sediment and alter its properties creating a bio-mineral medium. The microbially induced sedimentary structures (MISS) are the fossil record of an interaction between the physical environment and such a medium. The present report documents bedding surface structures from the Cisuralian (Asselian) Sandstone Building Member (BSM) of the Słupiec Formation, a unit that outcrops in the south-western Poland, in the Sudetes Mountains. The BSM represents likely continental (fluvial) sedimentary settings. The sedimentary structures on bedding surfaces in the BSM are interpreted as the MISS. The observations of the bedding structures are supplemented with thin section data that support the microbial interpretation of the bedding surface structures. The Słupiec Formation MISS record supplements the global patchy fossil record of the post-Cambrian (Paleozoic) MISS from the non-marine settings.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140441755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NEOICHNOLOGY OF TROPICAL AND ARID SCORPIONS: ENVIRONMENTAL IMPACTS ON BURROW CONSTRUCTION AND FORM","authors":"Skyler Houser, Daniel I. Hembree","doi":"10.2110/palo.2023.019","DOIUrl":"https://doi.org/10.2110/palo.2023.019","url":null,"abstract":"\u0000 Scorpions are intermediate predators in numerous terrestrial environments, and many are temporarily to permanently fossorial. As a result, they play key roles in terrestrial food webs, in soil development, and as ecosystem engineers. However, scorpions have a poorly described ichnofossil record likely due to an inadequate understanding of their trace morphology. Critical to correcting this is assessing the variability of burrows constructed by phylogenetically, geographically, and environmentally distinct scorpions. Five extant scorpions, Heterometrus spinifer, Pandinus imperator, Pandipalpus viatoris, Hadrurus arizonensis, and Paravaejovis spinigerus were studied through neoichnological experiments under varying substrate conditions. Burrow casts produced were described and compared across species and different substrate conditions. Tropical scorpions excavated sediment and carried it away from the burrow to produce open, straight-to-sinuous, subvertical tunnels to branching tunnel systems with single to multiple entrances and often chambers. Arid scorpions excavated with rapid leg movements to throw sediment behind the body to produce single to linked networks of U-shaped burrows as well as subvertical tunnels to tunnel networks with single to multiple entrances and rarely chambers. Changes in sediment composition and moisture tended to reduce burrow production but did not significantly alter burrow morphology. All scorpion burrows, regardless of species, bore a moderate-to-high similarity despite differences in excavation styles and architecture suggesting that scorpions produce burrows of consistent form regardless of phylogenetic or environmental distance. The result of these studies provides key ichnotaxobases of scorpion burrows which can be used to identify them in the fossil record and improve interpretations of ancient terrestrial ecosystems.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140439955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NEOICHNOLOGICAL ANALYSIS OF MOLE CRICKET BURROWS: IMPLICATIONS OF SUBSTRATE MOISTURE CHANGES ON PRESERVATION AND MORPHOLOGY","authors":"Daniel Sedorko, Diego L. Nascimento, Noelia Carmona, Renata G. Netto, Caio César Rangel, Kimberly Silva Ramos, Luciano Alessandretti","doi":"10.2110/palo.2023.028","DOIUrl":"https://doi.org/10.2110/palo.2023.028","url":null,"abstract":"\u0000 The morphology and architectural design of trace fossils are strongly influenced by substrate characteristics, organism anatomy, and burrowing behavior. In this study, we explore the influence of substrate moisture on preservation variants of mole cricket burrows and discuss its correspondence to previously described ichnogenera. Field observations were conducted on clayey and sandy substrates; burrows were described and photographed in situ, and laboratory analyses were performed on collected samples. Mole cricket burrows consist of branched, straight to sinuous tunnels with circular to semicircular cross sections and exhibit distinctive features on the inner walls that are influenced by substrate moisture and texture. Morphotypes were identified based on substrate characteristics, including well-developed pelletized roofs, subtle scratch traces, collapsed roofs, and lateral fringes. Understanding the impact of substrate moisture changes on the preservation and morphology of mole cricket burrows is essential for interpreting trace fossils in paleoenvironmental reconstructions. Besides providing insights into the modes of preservation and substrate conditions of mole cricket burrows, this study also compares their preservation variants with those of Protovirgularia and Sphaerapus.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140487817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"HYBRID NATURE OF A NEW JURASSIC–CRETACEOUS WORM BURROW INDICATED BY MICROBIAL MEDIATION OF ITS WALL FORMATION","authors":"Bogusław Kołodziej, Iuliana Lazăr, I. Bucur, Mariana Coman, Alfred Uchman","doi":"10.2110/palo.2022.042","DOIUrl":"https://doi.org/10.2110/palo.2022.042","url":null,"abstract":"\u0000 A new trace fossil Macroterebella hoffmanni nov. igen., nov. isp. occurs in Oxfordian and Aptian limestones of Romania, in the Central Dobrogea and the Rarău Mountains, respectively. It is a tubular, branched, and winding burrow (5–14 mm in diameter) displaying a thick wall (0.8–2 mm) with a micropeloidal texture. The Dobrogea burrows contain abundant calcite pseudomorphs after dolomite in the wall. A ferruginous halo occurs around burrows from Rarău. The burrow lumen resulted from burrowing by the tracemaker, most likely a polychaete worm of the family Terebellidae, while the wall is nonconstructional, and its formation was microbially mediated. Terebellids produce mucous-lined burrows, which are attractive for microbial activity which is geochemically important for metal adsorption and mineral nucleation. The micropeloidal texture of the Macroterebella wall is the result of bacterially mediated precipitation and possibly influenced by extracellular polymeric substances (EPS). Some microbes, especially sulphate-reducing bacteria producing extracellular polymeric substances (EPS) are able to mediate the formation of dolomite, and some microbial cells may be nucleation sites for dolomite. The lack of dolomite and the presence of a ferruginous halo around the burrows in the Rarău specimens may reflect different environmental geochemical conditions within these burrows compared with those from Dobrogea. This study confirms that microbes and organic matter in the mucous lining of burrows in a carbonate environment may play an important physicochemical role in the final appearance of trace fossils. Macroterebella nov. igen. can be considered as a trace fossil with a hybrid bioturbation/biosedimentary nature.","PeriodicalId":54647,"journal":{"name":"Palaios","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140486640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}