Oichnus Simplex Research Articles

PREDATION ON NEOGENE OSTRACODS OF SOUTHWESTERN SPAIN

This paper analyzes the evidence for predation on ostracods observed in Neogene sediments of southwestern Spain. Eighty bored valves were extracted from the analysis of more than 2000 specimens collected in shallow marine to upper bathyal palaeoenvironments. Bored specimens are more abundant in Neogene shallow marine areas, although very high percentages can be obtained in deeper sediments with very low ostracod densities. Two main types of boreholes can be distinguished, being concentrated mainly in the central areas of the valves, and drilled mainly by the gastropods: a) Oichnus paraboloides Bromley, with more of 70% of the total boreholes; and b) Oichnus simplex Bromley. Borehole diameter shows a positive but no significant correlation with the dimensions of the predated valves. Ornamentation seems to be secondary in the predatory selection.

Ichnology of a dolomitized raised reef: Hopegate Formation, Jamaica (Upper Pliocene)

The Upper Pliocene Hopegate Formation of north central Jamaica is a dolomitized raised reef. Hitherto, its palaeontology has been largely ignored because of the poor preservation; the Hopegate Formation is highly karstified, well indurated and fossils are commonly preserved as molds. However, moldic preservation has enhanced the common borings. Ichnotaxa identified from this formation include Entobia ovula? Bromley and d’Alessandro; Entobia ispp.; Gastrochaenolites isp. cf. G. torpedo Kelly and Bromley; Gastrochaenolites pickerilli Donovan; Gastrochaenolites ispp.; Oichnus simplex Bromley; Rogerella isp. cf. R. lecontrei Saint-Seine; Talpina isp. cf. T. hirsuta Voigt and Uniglobites flomerata (Morris). There are more specimens of Entobia than all other ichnotaxa combined. Comparison with other Neogene formations or members in the Antilles demonstrates that the association Entobia + Gastrochaenolites + Oichnus is near-ubiquitous. Caulostrepsis Clarke, which is common in modern shallow water environments in association with Entobia and Gastrochaenolites, is less common in the ancient associations of the Antilles.

Drilling predation on juvenile and adult gastropod shells during the Pliocene in the eastern Pacific, southern Mexico

Quantifying the effects of drilling predation on juvenile and adult gastropods is important for understanding the paleoecology of communities. Although numerous studies have examined predation on adult shells, virtually no reports cover juvenile specimens. We compare predation frequency and prey effectiveness between juvenile and adult gastropods in a Pliocene assemblage from the eastern Pacific of Mexico. Evidence of predation in the sample was confirmed by the presence of drilling in the shells, ascribed to Oichnus simplex Bromley, 1981 and O. paraboloides Bromley, 1981, which showed active predation by caenogastropods. The occurrence of drilling gastropods in the same locality reveals the possible predators as naticids (Polinices intermeratus (Philippi, 1853), and Natica broderipiana Récluz, 1844) and muricids (Eupleura vokesorum Herbert, 2005 and Thypina sp.). Some differences were found in predatory patterns between drilling gastropods, naticids drilled at a higher frequency than muricids in adults, while the opposite occurs in juveniles. Prey Effectiveness (PE) values were 0.00 for juveniles and 0.02 for adults.

Possible drill holes and pseudoborings in obolid shells from the Cambrian/Ordovician boundary beds of Estonia and the uppermost Cambrian of NW Russia

ABSTRACT Rare Oichnus simplex drill holes occur in mature obolid shells from the Cambrian/Ordovician boundary beds of northern Estonia (Iru and Ülgase) and the uppermost Cambrian of NW Russia (Lava River). The drill holes are significantly more common in the central rather than the marginal regions of the obolid valves. Drilling predators attacked Ungula ingrica in the Kallavere Formation and Ungula convexa in the Ladoga Formation. Failed predatory attacks on obolids were relatively common in the latest Cambrian-earliest Tremadocian of Estonia. Presumably drilling predators at Lava River and Iru differed from those at the Ülgase as indicated by significant differences in drill hole sizes at these locations. Most likely some types of worms preyed on obolids in the latest Cambrian-earliest Tremadocian of Estonia and latest Cambrian of NW Russia. The predation rate (6% to 9%) of studied obolids indicates that they likely had an epibenthic life mode. In addition to Oichnus drill holes in the obolids, there are also common pseudoborings caused by mineral dissolution.

Evidence of Predation on Early Pleistocene Freshwater Ostracods (Umbria, Central Italy)

Although drillholes in modern and ancient ostracods are known, the record is relatively scarce when compared to other taxa, and mainly exist with reference to the marine environment. Moreover, less is known about perforated ostracods, and more generally, about bioerosion in freshwater environments. Traces of predation on freshwater ostracods are reported for the first time in deep-lake deposits belonging to the early Pleistocene Fosso Bianco Unit, and outcropping in the Cava Nuova section (Umbria, central Italy). Deposits are mainly clay to silty clay and sand; the fossil record is sparse, and is mainly comprised of very rare gastropods and bivalves, ostracods and plant remains (leaves, seeds and wood’s fragments). The association of ostracods consists of Candona (Neglecandona) neglecta, Caspiocypris basilicii, Caspiocypris tiberina, Caspiocypris perusia, Caspiocypris tuderis, Caspiocypris posteroacuta, and Cyprideis torosa. The Caspiocypris group, considered to be endemic to the grey clays of the Fosso Bianco Unit, present the majority of specimens affected by predation, with a prevalence of predated female valves and a comparable number of right and left predated valves, while only a few of Candona(N.) neglecta (adult and juvenile) valves are perforated. Traces of predation for nourishment, represented by microborings of different types, were abscribed to the ichnospecies Oichnus paraboloides Bromley 1981, Oichnus simplex Bromley 1981, Oichnus gradatus Nielsen and Nielsen 2001, Oichnus ovalis Bromley 1993, and Dipatulichnus rotundus Nielsen and Nielsen 2001. Microboring affected both adult and juvenile specimens, evidencing prey–predator coexistence in the same environment over a long period of time. This report makes a fundamental contribution to the knowledge of predation in this peculiar confined environment, also suggesting prey–predator relations over a relatively short time interval (80–160 ka).

Fossichnus solus and Oichnus simplex, two peculiar ichnospecies in modern benthic foraminifera from a polluted area in SW coast of Sardina, Italy

The modern benthic foraminiferal tests collected from a coastal area of south-western Sardinia (Portoscuso-Portovesme) that is heavily polluted by industrial activity reveal intense and widespread bioerosional structures induced by diversified microborers. A large number of the foraminifera reveals microscopic round holes (1-60 μm in diameter) and roundish concavities (25x40 μm in external diameter) on their surface that belong, respectively, to the ichnospecies Oichnus simplex Bromley, 1981, and Fossichnus solus Nielsen et al., 2003. These traces just occur in the tests of the foraminifera which are heavily infested by microendolithic cyanobacteria, algae and fungi suggests comparable ethological behaviour between the ichnospecies Fossichnus and Oichnus and the microbial euendoliths that are ascribed to individual biological taxa. The greater occurrence of F. solus and O. simplex in the high-Mg foraminiferal porcelanaceous tests than in the low-Mg foraminiferal hyaline tests reveals that the bioerosional processes seem to be related to the Mg/Ca ratio, as well as to morphological structures of the taxa

Gastrochaenolites ichnofacies from intertidal seashells, Al-Khobar coastline, Saudi Arabia

Bioerosional structures and encrusters on a total of 349 bivalves and 209 gastropod shells were studied from Al-Khobar coastline along the Arabian Gulf, Saudi Arabia. Nine ichnospecies belonging to five ichnogenera were identified, namely: Entobia geometrica, Entobia isp., Oichnus paraboloides, Oichnus simplex, Gastrochaenolites dijugus, Gastrochaenolites isp., Caulostrepsis taeniola and Maeandropolydora isp. Barnacles, serpulids, bryozoans and bivalves were recoded as encrusters on the internal and external surfaces of the investigated seashells. The studied bioerosional structures were defined as Gastrochaenolites-dominated ichnoassemblage, which is composed of Gastrochaenolites, Oichnus and borings of polychaete annelids and clionid sponges. It reflects marine conditions, in a shallow water depth and low rates of sedimentation. A postmortem colonization has been confirmed on the basis of the presence of different encrusters on the internal surfaces of many seashells, while those on the external surfaces indicated a colonization process mostly took place during the lifetime of the seashells.

Oichnus simplex Bromley infesting Hemipneustes striatoradiatus (Leske) (Echinoidea) from the Maastrichtian type area (Upper Cretaceous, The Netherlands)

The large holasteroid echinoid Hemipneustes striatoradiatus (Leske) was exploited by diverse invertebrate encrusters and borers during the Maastrichtian, both pre- and post-mortem. In life, the specimen described herein was perforated by multiple Oichnus simplex Bromley borings close to the apical system. Each engendered a growth reaction from the echinoid, a mound-like swelling on the external surface of the test with the boring at the centre. These would have been moved away from the apical system as the echinoid grew and inserted new plates apically. Whether this infestation was the product of numerous individual organisms or, less likely, just one organism (gastropod?) that relocated when discouraged by each mound-like swelling is uncertain. Similar growth reactions are known from other echinoderms, but associated with non-penetrative Oichnus paraboloides Bromley.

A small yet occasional meal: predatory drill holes in Paleocene ostracods from Argentina and methods to infer predation intensity

AbstractOstracods are common yet understudied prey item in the fossil record. We document drill holes in Paleocene (Danian) ostracods from central Argentina using 9025 specimens representing 66 species. While the percentage of drilled specimens at assemblage‐level is only 2.3%, considerable variation exists within species (0.3–25%), suggesting prey preference by the drillers. This preference is not determined by abundance because no significant correlation is found between species abundance and drilling percentages. Seven methods were used, some of which are new, to quantify drilling percentages for the abundant and commonly drilled Togoina argentinensis. The resulting range, from 9.9% to 14.6%, suggests that drilling percentages are fairly insensitive to the method used, implying that comparisons across studies are possible. This information, combined with data from the literature, suggests the Cretaceous–Palaeogene mass extinction may have had a limited effect on drilling intensity in ostracods. The cylindrical (Oichnus simplex) and parabolic (O. paraboloides) drill holes from Argentina may have been caused primarily by naticid and possibly muricid gastropods. Two oval drill holes (O. ovalis) are morphologically similar to octopod drill holes, but their small size, the fact that extant octopods are not known to drill ostracods and the absence of such holes in co‐occurring gastropods, preclude ascription to a predator clade. Drill holes are located preferentially in the median and dorsal regions, where most soft tissue, including the adductor muscle, is located. Drilled specimens are statistically taller than non‐drilled specimens for T. argentinensis and larger predators selected larger ostracods. The drilling percentage does not significantly differ in ornamented ostracods.

Invertebrate borings from the Eocene of Seven Rivers, parish of St. James, western Jamaica

The fossil biota of the Eocene Yellow Limestone Group of Jamaica is diverse in vertebrates and, particularly, invertebrates. However, its invertebrate trace fossils remain understudied. Herein, we document the borings of the Seven Rivers vertebrate site in western Jamaica. This is in the Litchfield Formation, high in the Lutetian (about mid-Middle Eocene). The suite of borings identified from this site comprises Apectoichnus longissimus (Kelly and Bromley); Entobia isp.; Oichnus simplex Bromley; and Oichnus paraboloides Bromley. Substrates infested by Entobia isp. include both molluscs and sirenian ribs. Oichnus ispp. occur only in bivalves and are mainly non-penetrative, which may be a taphonomic artifact. Tubes of the common A. longissimus are preserved free from any woody substrates, which have presumably rotted away; however, one specimen has a dark, carbonaceous external film and others have carbonized wood inclusions. The occurrence of A. longissimus in the Jamaican rock record coincides with periods of sub-aerial exposure.

Microborings as indication of cryptic life modes in the foraminifer Orbitoides: Maastrichtian sediments of the Haymana and Nallıhan districts (Ankara, Turkey)

Widespread Maastrichtian siliciclastics and carbonates cropping out in the Haymana (S Ankara) and Nallıhan (NW Ankara) districts in the northwest and central Anatolia basins include rich Orbitoides occurrences. Microborings in the Orbitoides tests are interesting to notify. In this study, the details of their morphologic structures were investigated. Microborings were analyzed in more than 650 equatorial thin sections of the Orbitoides tests and 100 hard rock thin sections. The abundance of microborings increases in the siliciclastics towards the Cretaceous/Palaeogene boundary (K/Pg). They were identified as Maeandropolydora osmaneliensis Nielsen and Görmüş, Maeandropolydora isp. Curvichnus semorbis Nielsen, Oichnus simplex Bromley, Oichnus isp. Maeandropolydora osmaneliensis Nielsen and Görmüş. Maeandropolydora isp., semicircular to circular microborings of Curvichnus semorbis Nielsen and Oichnus simplex Bromley are related to parasitic life modes. Irregular wider unidentified microborings are hermit type life mode tunnels. Abundance of the microborings might be related to shallower siliciclastic environmental conditions such as feeding and suitable Eh-pH, test shape, and easy entrance to the test for parasites. Smaller benthic foraminifera are seen in both microspheric and megalospheric Orbitoides tests as parasites. In conclusion, occurrences of microborings and encrustations are associated with parasitism by appearances of Maeandropolydora osmaneliensis Nielsen and Görmüş, Curvichnus semorbis Nielsen and Oichnus simplex Bromley and commensally attachment by microalgae.

Ichnofossiles associés à des coquilles de lingulides du Permien inférieur du Brésil

Lingulides from Lower Permian of Brazil (24% substrates) showed signs of bioerosion in form of multiple small shallow pits that resemble incomplete Oichnus paraboloides borings. A single lingulide valve showed a centrally located large circular predatory Oichnus simplex boring. Several lingulide shells (c. 21%) show small Arachnostega traces in their interior. The diameter of Arachnostega burrows is relatively constant. These burrows are more similar to juvenile stages of Arachnostega gastrochaena and do not form well-developed meshwork of tunnels. This is the first record of Arachnostega from the interior of lingulide shells and indicates that even very small lingulide shells were suitable substrates for cryptic organisms.

Morpho-sedimentary characteristics and generated primary sedimentary structures on the modern microtidal sandy coast of eastern Nile Delta, Egypt

Spatial distribution and implication of primary sedimentary structures are combined with morpho-sedimentary features to suggest a sedimentologic–neoichnological model for the low microtidal sandy coast of eastern Nile Delta. Ten linear transects normal to the shoreline were investigated across four to five parallel geomorphic landforms. Intertidal sub-environment is characterized by abundant marine-affinity surface sedimentary structures (such as beach cusps, swash marks, air holes/volcanoes, foam impressions, raindrop imprints, rill marks and tool marks) in addition to the parallel lamination and oscillation ripples. Lower supratidal sub-environment is characterized by parallel lamination, current and wind ripples. Nebkas and wind ripples dominate the nebka/inter-nebka landforms, whereas microbial-induced sedimentary structures which including cyanobacterial mats, efflorescent salt crusts, polygonal cracks and tepee structures prevail in salinas and sabkhatized landform. Marine life-trace assemblage in the intertidal zone, belonging to infaunal and epifaunal bivalves and gastropods, resembles the poor expressions of shallow-marine Skolithos ichnofacies. Predation holes in bivalves and clavate borings in drifted tree trunks are analogous to Oichnus simplex and Teredolites isp., respectively. Transitional marine life-trace assemblage of abundant ghost crab burrows and trackways represents a modern example of seaward suites of the paleoichnological backshore Psilonichnus ichnofacies. Terrestrial life-trace assemblage of beetles, ants, vertebrate tracks and rhizoliths show similarity to the landward expression of Psilonichnus ichnofacies. Despite low to moderate preservation potentiality of modern microtidal sedimentary structures, the preserved structures are invaluable in revealing depositional processes and paleoenvironments of ancient coastal systems.

Site selection of small round holes in crinoid pluricolumnals, Trearne Quarry SSSI (Mississippian, Lower Carboniferous), north Ayrshire, UK

Small round holes, Oichnus Bromley, are a locally common feature of crinoid pluricolumnals in the Mississippian of the British Isles. Numerous examples have been found from mudrocks in the Brigantian (Mississippian) Blackhall Limestone, Lower Limestone Formation, at Trearne Quarry, near Beith, north Ayrshire, all assigned to Oichnus simplex Bromley. These trace fossils are typically associated with growth deformities of the pluricolumnals, which are commonly swollen and more rarely grew a lip around the pit. Oichnus simplex is commonly centred on a columnal latus and adjacent sutures between columnals are deflected towards it. More rarely, pits are centred on the sutures between columnals. The O. simplex borings are interpreted as domiciles developed in live crinoids by an indeterminate, unmineralized invertebrate. The pluricolumnals are similar and are presumed to be derived from a single species, perhaps the poteriocrinine cladid Ureocrinus bockshii (Geinitz), the only nominal crinoid recorded from this site.

Macrobioerosion and Microbioerosion in Marine Molluscan Shells from Holocene and Modern Beaches (39°–40°S, South of Buenos Aires Province, Argentina)

AbstractThe marine sediments of the area of Verde Peninsula – Jabali Island (39°28′S/62°19′W–40°28′S/62°11′W) Holocene in age (3–2 ky), and modern beaches contain a significant amount of bioeroded mollusc shells. Fifteen sites were analyzed, in which 20.11% of the mollusc shells (2168 valves) presented bioerosion traces, in 54 species (30 bivalves and 24 gastropods). Fourteen ichnogenera were reported: Entobia, Maeandropolydora, Iramena, Caulostrepsis, Pennatichnus, Pinaceocladichnus, Trypanites, and Gastrochaenolites (Domichnia), Gnathichnus and Radulichnus (Pascichnia), Finichnus and Centrichnus (Fixichnia), Oichnus (Praedicnia) (macrobioerosion), y Semidendrina (microbioerosion), the latter is first reported in mollusc shells in Argentina. Eleven ichnospecies were identified Finichnus peristroma, Maeandropolydora sulcans, Gnathichnus pentax, Pinaceocladichnus onubensis, Caulostrepsis taeniola, Centrichnus eccentricus, Radulichnus inopinatus, Oichnus simplex, Oichnus paraboloides, Oichnus gradatus, and Gastrochaenolites torpedo (lithic remains). The dominant ichnogenera in the Holocene deposits are Iramena, Entobia and Oichnus. The same ichnogenera are constant with different abundance in the modern beaches, and increasing representation of Pinaceocladichnus and Pennatichnus. The dominant ichnofacies in the Holocene deposits is Trypanites, revealing a benthonic marine community composed of cheilostome bryzoans, clionaid sponges, predator gastropods, regular echinoids, polychaete annelids, bivalves, thallophytas and fungi. Generally, the area was described as a sublittoral, low‐energy, stable environment with high rate of oxygenation, and sandy bottoms, with rocky bottoms at Villalonga locality.

Reworked crinoidal cherts and screwstones (Mississippian, Tournaisian/Visean) in the bedload of the River Maas, south-east Netherlands

Rare Palaeozoic chert clasts collected from gravels in the bedload of the River Maas in the province of Limburg, south-east Netherlands, are rich in crinoid debris. These were transported during the Late Pliocene–Pleistocene by fluvial action from the southern Ardennes Massif (Namur-Dinant area, southern Belgium) and are of Early Carboniferous (Mississippian) age. Clasts are either completely chertified or may preserve macrofossils as natural moulds in a chert matrix; the latter are screwstones, a well-known lithology from rocks of this age. One screwstone preserves its fossiliferous debris, mainly crinoid columnals and pluricolumnals, in exquisite detail, including an archetypal ‘screw’, the mould of the axial canal. But the delicate ‘screw’ is not always preserved after fluvial transport. Further, the best-preserved specimen retains a mould of a pit in the latus, Oichnus simplex Bromley, probably a domicile excavated by an unmineralized invertebrate after the death of the crinoid.

THE FIRST PREDATORY DRILLHOLE ON A FOSSIL CHITON PLATE: AN OCCASIONAL PREY ITEM OR AN ERRONEOUS ATTACK?

ABSTRACT Drillholes represent direct evidence of ecological interactions in the fossil record. Most of them have been interpreted as predatory in origin and enable the analysis of behavioral information of both predator and prey. Drillholes have been found in a variety of fossil organisms, but this is the first report of a bored fossil chiton plate. It was found in the La Coronilla deposit, a Late Pleistocene invertebrate assemblage from southeastern Uruguay. The drillhole belongs to the ichnospecies Oichnus simplex and is attributed to a muricid gastropod, which could likely have been the ocenebrinid Urosalpinx haneti, recorded in the fossil assemblage. The drillhole features all traits for a predatory origin. However, the rareness of this particular interaction between chitons and gastropods in the fossil record and in the recent, could signify an event of arbitrary drilling. The reported occurrence here raises the question as to whether this behavior represents an understudied ecological interaction be...

Neoichnology and implications for stratigraphy of reworked Upper Oligocene oysters, Antigua, West Indies

Abstract The Late Oligocene oyster Hyotissa antiguensis (Brown) is locally common in the Antigua Formation of Hughes Point, eastern Antigua, Lesser Antilles; it was not commonly bored at that time. Its valves and shells are robust, and reworked into the shallow water near-shore environment in Antigua; it could potentially be incorporated into younger rocks. Its neoichnology includes clues that would facilitate identification of these oysters as reworked fossils. The suite of modern borings found in these specimens includes common Caulostrepsis taeniola Clarke, Gastrochaenolites isp. cf. G. turbinatus Kelly and Bromley and Entobia isp., and rare Oichnus simplex Bromley and Rogerella ? isp. The latter three taxa are limited to oyster shell substrates. Of the common ichnotaxa, Caulostrepsis and Gastrochaenolites are particularly prominent in limestone clasts and limestone cemented to oyster shells, which would be an indicator of reworking if found in a post-Oligocene lithified deposit. Caulostrepsis and Gastrochaenolites are relatively less common in oyster shells and valves, and in many specimens are seen to terminate against the shell. Entobia is the only common boring limited to the shell substrate. The fidelity of preservation of modern borings is also superior in limestone clasts. This suite of borings is comparable with those found in the Neogene of the Antillean region.

Site Selectivity of the Pit Oichnus excavatus Donovan and Jagt Infesting Hemipneustes striatoradiatus (Leske) (Echinoidea) in the Type Maastrichtian (Upper Cretaceous, The Netherlands)

Two tests of the holasteroid echinoid Hemipneustes striatoradiatus (Leske) from the type area of the Maastrichtian Stage (Upper Cretaceous) bear a varied infestation of episkeletozoans (oysters, bryozoan colony, and serpulids), borings (probable Caulostrepsis isp., Oichnus simplex Bromley), surface abrasion (Gnathichnus? isp.), and pits (O. excavatus Donovan and Jagt). Only O. excavatus represents a premortem infestation. In one specimen, the four individual pits of this ichnospecies are each associated with a different ambulacrum and pore pairs that, in life, bore respiratory tube feet; the anterior ambulacrum, of different gross morphology, is not infested. In the second test, three out of four of the same ambulacra are infested, although there are also O. excavatus in the interambulacra. The association between O. excavatus and the ambulacra of the echinoid, and thus its tube feet, is open to several plausible explanations, but most likely provided some form of feeding or protective advantage to the pit-forming organism.

Taphonomy and palaeoecology of the gastropod fauna from a Late Cretaceous rocky shore, Sweden

A gastropod fauna comprising 17 species, each represented by a limited number of specimens, is described from a Late Cretaceous, late early Campanian rocky shore at Ivö Klack, southern Sweden. The gastropod fauna is associated with the most diverse ancient rocky shore fauna ever found. However, the low gastropod species diversity compared to the faunas of modern rocky shores is ascribed to taphonomic factors, notably dissolution of the aragonitic shells, but the predominance of epifaunal herbivores is indicative of a guild structure similar to that found on modern rocky shores. The presence of drill holes assigned to the ichnospecies Oichnus simplex suggests the former presence of muricid gastropods which have not been found as body fossils. A single drill hole is referred to Oichnus paraboloides and was probably made by a naticid gastropod. The infaunal mode of life of naticids makes preservation of such drill holes difficult, since the majority of infaunal prey such as burrowing bivalves has aragonitic shells which are not preserved. The relatively high number of species in comparison to many other Late Cretaceous rocky shore faunas, offers an opportunity to compare gastropod guild structure at Ivö Klack with modern counterparts, even though taphonomic processes such as mechanical destruction and aragonite dissolution have played an important role in the fossil gastropod assemblage.