Fossil Worm Research Articles

Light and Electron Microscopy Study of Opportunistic Free-Living Nematodes Scavenging and Thriving within Buried Dinosaur Bones

Abstract Nematode worms are the most abundant multicellular organism on Earth. They thrive in every habitat known, and they are voracious feeders within the top 70 cm of soils. Their sturdy cuticle protects them from environmental factors and predators. Nematodes play a significant role in the decomposition of vertebrate remains in soil and serve as indicators of nutrients that enter soils during decomposition. Certain parasitic nematodes have been identified in fossil remains, but reports of fossil worms are rare. We demonstrate the abundant presence of opportunistic nematodes feeding within dinosaur bones from the Hell Creek formation, MT. The presence of visible worm ultrastructure indicates that they were alive when preserved within the dinosaur bones. Our findings are identical to worms characterized as “blood parasites” in a dinosaur bone from Brazil, demonstrating that there is sufficient soft tissue within dinosaur bone canals to sustain large populations of nematodes post-mortem.

When a Worm Loves a Coral: A Symbiotic Relationship from the Jurassic/Cretaceous Boundary

Reefal limestones of the Štramberk Carbonate Platform are preserved as olistoliths and pebbles in deep-water flysch of the Outer Carpathians (Czech Republic, Poland). They contain the richest coral assemblages of the Jurassic/Cretaceous transition (Tithonian–Berriasian). Symbiotic associations between corals and tube-dwelling macroorganisms were recognized only in the branching scleractinian corals Calamophylliopsis flabellum and Calamophylliopsis sp. One to seven calcareous tubes were recognized either in coral calyces, embedded in the wall, or attached to it. Two types of tubes were recognized: Type 1: tubes with a diameter of 0.3–0.6 mm and a very thin wall (ca. 0.05 mm), mostly occurring inside corallites, and nearly exclusively in the Štramberk-type limestone of Poland; Type 2: tubes with an outer diameter of 0.8–2.0 mm and a thick wall (ca. 0.1 mm, some even up to 0.2 mm), mostly found in the Štramberk Limestone of the Czech Republic. Growth lamellae were observed in some thick walls. Most tubes are almost straight, some are curved. The tubes were probably produced by serpulids or by embedment of organic-walled sabellid polychaete worms. It is likely the oldest record of a sabellid–coral association. Modification of the coral skeleton in contact with tubes indicates that the worms were associated with live corals. For many modern and fossil worm–coral associations, this symbiotic association is interpreted as mutualistic or commensal.

Characterization of ferromanganese crusts from the Central and South West Indian ridges: Evidence for hydrothermal activity

Ferromanganese (FeMn) crusts with oxides ranging from a thin coating to a maximum of 5 cm thickness were recovered from the South West Indian Ridge (SWIR) and Central Indian Ridge (CIR) segments. The substrate for the oxides are altered mafic, ultramafic, and serpentinite rocks. Twenty FeMn crusts were studied to determine their mineralogical compositions, microstructures, and chemical compositions. The crusts display rough botryoidal or smooth surface textures. Todorokite, hematite, goethite, and nontronite are the major minerals followed by vernadite, magnetite, and maghemite. Electron micrographs show framboids of FeMn oxides, fossil worms, foraminifera nuclei, and euhedral mineral crystals. The oxides have higher FeO wt% (27–47; average ∼43) than MnO (13–45, average ∼30), and the average wt% of SiO2 is ∼40, Al2O3 ∼3, MgO ∼2, CaO ∼4, Na2O ∼0.4, K2O, NiO ∼0.5, CuO ∼0.3, CoO ∼0.8, and P2O5 ∼1.5. Our studies indicate a hydrothermal origin for the crusts and this fact is corroborated by low MnO/FeO ratio (≤ 1) and occurrence of framboids and hydrothermal minerals. Negative Ce anomaly and the plot of Mn–Fe–10×(Ni + Co + Cu) indicate characteristic signatures of hydrogenous-hydrothermal origin for most of the studied FeMn crusts.

Identification of fossil worm tubes from Phanerozoic hydrothermal vents and cold seeps

One of the main limitations to understanding the evolutionary history of hydrothermal vent and cold seep communities is the identification of tube fossils from ancient deposits. Tube-dwelling annelids are some of the most conspicuous inhabitants of modern vent and seep ecosystems, and ancient vent and seep tubular fossils are usually considered to have been made by annelids. However, the taxonomic affinities of many tube fossils from vents and seeps are contentious, or have remained largely undetermined due to difficulties in identification. In this study, we make a detailed chemical (Fourier-transform infrared spectroscopy and pyrolysis gas-chromatography mass-spectrometry) and morphological assessment of modern annelid tubes from six families, and fossil tubes (seven tube types from the Cenozoic, 12 Mesozoic and four Palaeozoic) from hydrothermal vent and cold seep environments. Characters identified from these investigations were used to explore for the first time the systematics of ancient vent and seep tubes within a cladistic framework. Results reveal details of the compositions and ultrastructures of modern tubes, and also suggest that two types of tubes from ancient vent localities were made by the annelid family Siboglinidae, which often dominates modern vents and seeps. Our results also highlight that several vent and seep tube fossils formerly thought to have been made by annelids cannot be assigned an annelid affiliation with any certainty. The findings overall improve the level of quality control with regard to interpretations of fossil tubes, and, most importantly, suggest that siboglinids likely occupied Mesozoic vents and seeps, greatly increasing the minimum age of the clade relative to earlier molecular estimates.

Bivalve shell horizons in seafloor pockmarks of the last glacial‐interglacial transition: a thousand years of methane emissions in the Arctic Ocean

AbstractWe studied discrete bivalve shell horizons in two gravity cores from seafloor pockmarks on the Vestnesa Ridge (∼1200 m water depth) and western Svalbard (79°00′ N, 06°55′ W) to provide insight into the temporal and spatial dynamics of seabed methane seeps. The shell beds, dominated by two genera of the family Vesicomyidae: Phreagena s.l. and Isorropodon sp., were 20–30 cm thick and centered at 250–400 cm deep in the cores. The carbon isotope composition of inorganic (δ13C from −13.02‰ to +2.36‰) and organic (δ13C from −29.28‰ to −21.33‰) shell material and a two‐end member mixing model indicate that these taxa derived between 8% and 43% of their nutrition from chemosynthetic bacteria. In addition, negative δ13C values for planktonic foraminifera (−6.7‰ to −3.1‰), concretions identified as methane‐derived authigenic carbonates, and pyrite‐encrusted fossil worm tubes at the shell horizons indicate a sustained paleo‐methane seep environment. Combining sedimentation rates with 14C ages for bivalve material from the shell horizons, we estimate the horizons persisted for about 1000 years between approximately 17,707 and 16,680 years B.P. (corrected). The seepage event over a 1000 year time interval was most likely associated with regional stress‐related faulting and the subsequent release of overpressurized fluids.

Fossil Worm Burrows Reveal Very Early Terrestrial Animal Activity and Shed Light on Trophic Resources after the End-Cretaceous Mass Extinction

The widespread mass extinctions at the end of the Cretaceous caused world-wide disruption of ecosystems, and faunal responses to the one-two punch of severe environmental perturbation and ecosystem collapse are still unclear. Here we report the discovery of in situ terrestrial fossil burrows from just above the impact-defined Cretaceous-Paleogene (K/Pg) boundary in southwestern North Dakota. The crisscrossing networks of horizontal burrows occur at the interface of a lignitic coal and silty sandstone, and reveal intense faunal activity within centimeters of the boundary clay. Estimated rates of sedimentation and coal formation suggest that the burrows were made less than ten thousand years after the end-Cretaceous impact. The burrow characteristics are most consistent with burrows of extant earthworms. Moreover, the burrowing and detritivorous habits of these annelids fit models that predict the trophic and sheltering lifestyles of terrestrial animals that survived the K/Pg extinction event. In turn, such detritus-eaters would have played a critical role in supporting secondary consumers. Thus, some of the carnivorous vertebrates that radiated after the K/Pg extinction may owe their evolutionary success to thriving populations of earthworms.

Tubular worms from the Burgess Shale

The discovery, in 500-million-year-old rocks, of fossil acorn worms that lived in tubes illuminates the debate about whether the ancestor of vertebrates was a mobile worm-like animal or a sessile colony dweller. See Letter p.503 Enteropneusts, or acorn worms, are mud-dwelling creatures that live from the foreshore down to the deep ocean. They are related to pterobranchs, small, colonial, tube-dwelling animals that superficially look completely different. Both are related to echinoderms (starfish and allies) and chordates — the group of animals that includes ourselves. Here Jean-Bernard Caron and colleagues describe fossil enteropneusts from the famous Cambrian Burgess Shale of British Columbia. They look much like some modern enteropneusts, but lived in tubes, more like modern pterobranchs. This adds to the diversity of the fossil fauna and gives pointers to what the common ancestor of enteropneusts and pterobranchs looked like. It might also fuel the debate about whether the ancestor of chordates was a free-living worm, or a sessile, colonial creature.

Life: Marine animals moved upriver early: Fossil worm burrows suggest rapid colonization of freshwater

Life: Marine animals moved upriver early: Fossil worm burrows suggest rapid colonization of freshwater

Growth, decay and burial compaction of Dickinsonia, an iconic Ediacaran fossil

Retallack, G.J., September, 2007. Growth, decay and burial compaction of Dickinsonia, an iconic Ediacaran fossil. Alcheringa 31, 215-240. ISSN 0311-5518. Dickinsonia is a Neoproterozoic, Ediacaran fossil, variously considered a polychaete, turbellarian or annelid worm, jellyfish, polyp, xenophyophoran protist, lichen or mushroom. Its preservation as unskeletonized impressions in quartz sandstones has been attributed to a Neoproterozoic regime of aerobic decay less effective than today, microbial pyritization much nearer the surface than today, or agglutinate-mineralization as in xenophyophorans. However, the great variation in thickness independent of width or length of South Australian Dickinsonia is evidence of decay like the wilting of a fossil leaf, lichen or mushroom, but unlike clotting and distortion during decay, wilting or osmotic shrinkage of modern and fossil worms and jellyfish. Decayed specimens of Dickinsonia arrayed in arcs have been interpreted as slime trails or tumble tracks, but can also be interpreted as rhizinous bases of decayed crustose lichens or mushrooms arranged in fairy rings. Dickinsonia is interpreted to be sessile because adjacent specimens show reaction rims indicative of competitive interaction, and because no overlapping well-preserved specimens have ever been found. Folded and bent Dickinsonia reveal firm attachment and limited flexibility, but no brittle deformation indicative of pyritic, sideritic or calcitic ‘death masks’ or xenophyophoran agglutinate skeletons. Dickinsonia was resistant to compaction by overburden, like fossil lichens such as Spongiophyton and Thucomyces, and more compaction-resistant than fossil logs, jellyfish or worms. Dickinsonia also shows indeterminate growth like lichens, fungi, plants, xenophyophorans and colonial animals. Growth, decay and burial compaction of Dickinsonia were more like those of plants, lichens and fungi, than of worms, jellyfishes or anemones. G.J. Retallack [gregr@uoregon.edu], Department of Geological Sciences, University of Oregon. Eugene, OR 97403-1272, USA; received 18.11.05, revised 23.3.06.

Growth history of a diffusely venting sulfide structure from the Juan de Fuca Ridge: A petrological and geochemical study

Centimeter‐scale mineralogical and chemical analyses of a diffusely venting, ∼280°C sulfide structure (called Roane) from the Mothra Hydrothermal Field on the Juan de Fuca Ridge reveal a complex growth history. These analyses document four well‐defined zones, which from the exterior to the interior of the structure include a barite‐silica zone (Fossil Worm Tube Zone), a silica‐sulfide zone (Silica Zone), a sulfide‐silica zone (Outer Sulfide Zone), and a sulfide ± gordaite ± silica zone (Inner Sulfide Zone). These features are a product of a myriad of processes that include extensive mineral replacement, ingress of seawater, fracturing and breakout of hot hydrothermal fluids, significant conductive cooling, and the sustained, broad‐scale outflow of warm fluids from the walls through a porous and permeable matrix. Roane lacks an open, throughgoing, chalcopyrite‐lined, central conduit. Instead, it hosts an anastomosing, discontinuous network of tortuous channels within the interior of a sponge‐like matrix of amorphous silica, sulfide, sulfate, and clay minerals. Megafaunal communities at the summit and sides of this mature, diffusely venting chimney provide a constructional framework for new growth. Isolation of hydrothermal fluid from seawater during progressive fossilization of megafauna and the early formation of barite‐silica assemblages promote flow of higher‐temperature fluids within the interior. Continued isolation of interior higher‐temperature fluids, through increased mineral precipitation and expansion of the structure, leads to a Zn sulfide + pyrite‐dominated permeable matrix and a network of tortuous channels that form a central porous conduit. This conduit is shielded by a weakly silicified, metal sulfide inner wall and a strongly silicified outer wall. The most outer portions of the walls are highly porous and sites of significant advection and mixing between hydrothermal fluids and seawater. The mineralogy and chemistry of Roane are strongly affected by ammonia‐ammonium buffering of the pH during cooling of the hydrothermal fluids. The two major results of the buffering are (1) precipitation of Zn sulfide at higher temperatures than are typical for bare‐rock systems, leading to the correlation of Cu, Zn, Cd, and Se and (2) increased deposition of amorphous silica and clay minerals.

A new theca-bearing Early Cambrian worm from the Chengjiang Fossil Lagerstätte, China

An elongate worm from the Early Cambrian Chengjiang fossil Lagerstätte, Laojieella thecata gen. et sp. nov., is described on the basis of two specimens. Its unique body plan features a tapering, spinose proboscis, an elliptical theca on the posterior part of the trunk, and a caudal appendage. It is considered to be most closely related to cycloneuralians, especially priapulids, but cannot be firmly assigned to any known phylum. Some of the common characteristics like the spinose proboscis, shared by other proboscis-bearing fossil worms in the Early and Middle Cambrian, suggest that the common ancestor for cycloneuralians had a zoned proboscis. Based on the presence of sand grains in the gut, the animal is viewed as a detritus feeder probably with occasional preying.

Decastronema kotori gen. nov., comb. nov.: a mat-forming cyanobacterium on Cretaceous carbonate platforms and its modern counterparts

The fossil renamed here was first described in 1959 as Aeolisaccus kotori Radoicic, a new species of a problematic fossil worm, Aeolisaccus Elliott. In 1975 De Castro recognized the true identity of this microbial fossil: a cyanobacterium related closely to the modern genus Scytonema. The fossil is common in the sediments of the Mesozoic carbonate platforms of southern Europe. This contribution confirmed De Castro’s interpretation, determined, using the high resolution of the SEM, the extent to which these fossils have preserved their original architecture, and investigated their presumed modern counterparts among the abundant mat-forming species of Scytonema on the intertidal flats of Andros Island, a part of the Bahama carbonate platform. The systematic affinities of the fossil and the environments it inhabited were reconstructed by comparing the morphology of the fossils to that of their modern counterparts, along with their respective sedimentary contexts. Based on these comparisons, we conclude that the organism lived in a peritidal environment and was buried and fossilized in the shallow waters of an ancient carbonate platform. A formal transfer of the fossil to a new genus of fossil cyanobacteria thereby designated as Decastronema gen. nov. is proposed, honoring the contribution of Prof. Piero De Castro to paleontology.

Soft-bodied fossils from the Shipai Formation, Lower Cambrian of the Three Gorge area, South China

Mudstones and shales in the Lower Cambrian Shipai Formation in the Three Gorge area, Hubei, China, are richly fossiliferous, containing common shelly fossils and some soft-bodied fossils. The latter provide important new information about the nature and variety of Cambrian soft-bodied organisms. Identifiable, non-mineralized taxa include components of the Chengjiang fauna, such as Vetulicola Hou, 1987, a palaeoscolecidan referable to Maotianshania Sun & Hou, 1987, and a brachiopod Diandongiapista with pedicle preserved (not illustrated). Cambrorhytium Conway Morris & Robison, 1988, co-occurring both in the Burgess Shale and the Chengjiang Lagerstätte, was also recovered. Additionally, a new worm is described based on two specimens. This taxon, in common with many other fossil worms, has a slender, cylindrical body with annulations, but it is characterized by each annulus bearing an elevated ridge and lacking surface ornamentation. The occurrence of exceptional preservation in the Shipai Formation has likely been overlooked due to the relatively poor resolution of soft-bodied fossils; nevertheless, this occurrence is an important extension of the Burgess Shale-type biotas in China, over 1500 km northeast of the provenance of the Chengjiang Lagerstätte.

New fossil worms from the Lower Cambrian of the Kinzers Formation, Pennsylvania, with some comments on Burgess Shale-type preservation

Two new fossil worms are described from the Lower Cambrian Kinzers Formation of southeast Pennsylvania. Both are unique specimens.Kinzeria crinitanew genus and species has a body divided into three regions. The head bears a prominent set of elongate tentacles, presumably employed for feeding. The elongate trunk tapers slightly in a posterior direction. It contains a prominent intestinal tract, the contents of which indicate a deposit feeding habit. The tail is an expanded structure, with either a spatulate or sagittate outline. The mode of life ofK. crinitais uncertain, but the animal may have been semi-sedentary.Atalotaenia adelanew genus and species is more poorly known, lacking the anterior. The preserved body is vermiform, with external annulations and a rounded posterior. There is a prominent internal strand, consisting of a probable intestine and an associated fibrous unit, possibly representing muscles. This worm may have been infaunal. These discoveries extend further our understanding of the ancient diversity of Laurentian Burgess Shale-type faunas. In common with the Burgess Shale itself and the Sirius Passet fauna (Peary Land, Greenland) the location of fossil-Lagerstätte [see Shields (1998) for a discussion of the terminology of Lagerstätten] of the Kinzers Formation adjacent to a prominent escarpment reinforces earlier evidence of the paleotopography exerting an important control on the distribution of Burgess Shale-type faunas. Whether this is a result of localized faunal abundances or taphonomic control is, however, uncertain.

Fossil worm tubes from the presumed cold‐seep carbonates of the Miocene Hayama Group, Central Miura Peninsula, Japan

Abstract Fossil worm tubes were collected from the Hayama Group, Miura Peninsula, Japan, together with abundant fossils of Calyptogena‐Acharax clams. The fossil worm tubes were well preserved and coated with milky white amorphous silica. Most of the tubes were 1‐3 mm in diameter, and up to 10 cm in length. Worm tubes were found in siltstone and limestone, and formed network‐like assemblages. Elemental mapping on the tube cross‐sections revealed the localization of sulfur, zinc and iron at the worm tubes, which suggests that sulfur‐related metabolism and deposition occurred in association with the worm tubes. High resolution analysis revealed the localization of zinc‐sulfur (sphalerite, ZnS) on the tubes, while iron‐sulfur (pyrite, FeS2) was localized at the center of the tubes. The spatially separate sphaleritization and pyritization imply that epiphytic and endosymbiotic microorganisms perform different sulfur metabolisms, such as sulfate‐reduction and sulfide‐oxidation.

Fossil worms from the Devonian of North America (Sphenothallus) and Burma (“Vermes”) previously identified as phyllocarid arthropods

Fragmentary fossils from Late Devonian rocks, previously identified as phyllocarid arthropods, are referable to “Vermes.” Specimens identified as Dithyrocaris (=Mesothyra) sp. from the Chagrin Shale in northeastern Ohio are assigned to Sphenothallus cf. S. carbonarius (M'Coy). Thus, there are no records of rhinocaridid arthropods from the Chagrin. Fossils identified as “cercopods” of the echinocaridid, Echinocaris asiaticus Reed, from the Wetwin shales in Burma, are not arthropod remains, but are tubes produced by a gregarious worm. Echinocaris asiaticus is now represented only by a single partial carapace.

Donńees morphologiques, histochimiques et microanalytiques sur l'élaboration du tube organominéral d'Alvinella pompejana, Polychète des sources hydrothermales, et leurs implications Phylogénétiques

Vovelle, J. & Gaill, F. 1986. Données morphologiques, histochimiques et microanalytiques sur l'élaboration du tube organominéral d'Alvinella pompejana, Polychète des sources hydrothermales, et leurs implications Phylogénétiques. [Morphological, histochemical and microanalytical data on the elaboration of the organomineral tube of Alvinella pompejana, a polychaete from hydrothermal vents, and its phylogenetic implications.]The material elaborated by Alvinellu pompejuna Desbruyères & Laubier, 1980, a polychaete worm from hydrothermal vents in the East Pacific, to build up its tube originates from an anterior ventral ‘glandular shield'. Mucocytes rich in sulphated glycosaminoglycan provide an accessory component, but the bulk is formed from homogeneous granules, secreted by the deep ‘main’ cells of this shield. The organic part of the granules, as demonstrated by histochemistry, is proteinaceous, while the mineral part, as proved by microanalysis, includes phosphorus, calcium, iron and in smaller amounts magnesium and zinc. The material of the tube shows an increase in the ratio iron‐calcium. Phosphorus may be bound to the organic part, but there is no sulphur present in it. In the laminated tube, scanning electron microscopy and microanalysis detect an enrichment in heterogeneous components of different constitution (balls and crystals). Silica, pointed out as characteristic of fossil worm tubes but absent in secretions, is not of endogenous origin. The original composition of the Alvinella tube can thus be related to that of other examples of the order Terebellida who live in a less drastic environment.

Fossils of Hydrothermal Vent Worms from Cretaceous Sulfide Ores of the Samail Ophiolite, Oman

Fossil worm tubes of Cretaceous age preserved in the Bayda massive sulfide deposit of the Samail ophiolite, Oman, are apparently the first documented examples of fossils embedded in massive sulfide deposits from the geologic record. The geologic setting of the Bayda deposit and the distinctive mineralogic and textural features of the fossiliferous samples suggest that the Bayda sulfide deposit and fossil fauna are remnants of a Cretaceous sea-floor hydrothermal vent similar to modern hot springs on the East Pacific Rise and the Juan de Fuca Ridge.

A possible annelid from the Trenton Limestone (Ordovician) of Quebec, with a review of fossil oligochaetes and other annulate worms

A single specimen of fossil worm from the Trenton Limestone, recovered from a quarry northeast of Quebec City, may represent a new form that cannot be directly compared with any other known fossil or recent worm. The specimen is incomplete and shows evidence of decay, but the remarkable preservation of the surviving portion shows well defined transverse lines, interpreted as segmentation, and traces of internal organs. There is, however, no evidence for either setae or parapodia. In certain respects the anatomy of this worm is reminiscent of the annelids, and in particular the oligochaetes, but any similarity may be superficial. Other fossil worms that have been interpreted as oligochaetes are reviewed briefly, and a redescription of the worm Protoscolex covingtonensis Ulrich from the Eden Group (Ordovician) of Kentucky is given.

Strains and folds within thrust sheets: An analysis of the Heilam sheet, northwest Scotland

The changes of shape and orientation of fossil worm burrows have been used to carry out a detailed strain analysis of the Heilam thrust sheet in the Moine Thrust zone, northwest Scotland. The strains have been factorised into components of layer parallel shear ( γ 1), layer normal shear ( γ 2) and layer parallel shortening or elongation (√ λ). Variations in the γ 1 shear are largely lithologically controlled. Some strain is due to flexural processes as the thrusts and overlying beds change dip over thrust ramps, or are tightened by later deformation, while there may also be a component of drag which increases towards the overlying thrust, this predating the shear due to flexure. A contoured map of the √ λ′ values suggests that major folds within the thrust sheet developed as a result of stick or drag on the floor thrust prior to ramp climb. This led to differential movement in the transport direction causing layer parallel shortening accompanied, or followed by, buckling of the layers. A map showing layer normal shear strains, γ 2, suggests that the Heilam sheet forms a major surge zone, the central part having moved further WNW than the northern and southern parts. This has led to components of lateral shear along parts of the sheet, especially in the north, producing curvature of the imbricate faults.