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Tytuł:
The aperture and its closure in an Ordovician conulariid
Autorzy:
Sendino, C.
Zagorsek, K.
Vyhlasova, Z.
Powiązania:
https://bibliotekanauki.pl/articles/21543.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Ordovician
conulariid
fossil group
marine organism
fossil record
Ediacaran
Opis:
The conulariids, an enigmatic fossil group believed to be of cnidarian (scyphozoan) affinity, have four−sided, acutely pyramidal exoskeletons terminated in apertural closures. To date, three main closure types have been recognised in conulariids (plicated, triangular lappets, and lobate lappets) but the first type is poorly illustrated in the literature. Here we present the first photographic illustration of an unequivocal plicated closure in Metaconularia? anomala, based on study of the rich (1700+ specimens) material from the Upper Ordovician of the Prague Basin. This closure is formed by inwardly folded, triangular lappets centred on each of the four faces, with kite−shaped elements centred on the four corners forming a webbing between the lappets. Plicated closures were evidently rare in conulariids and restricted to a few Ordovician species.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New finds of skeletal fossils in the terminal Neoproterozoic of the Siberian Platform and Spain
Autorzy:
Zhuravlev, A.Y.
Linan, E.
Gamez Vintaned, J.A.
Debrenne, F.
Fedorov, A.B.
Powiązania:
https://bibliotekanauki.pl/articles/22120.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
skeletal fossil
Neoproterozoic
Siberian Platform
Spain
Cloudina
Ediacaran skeletal fossil
microstructure
extinction
Opis:
A current paradigm accepts the presence of weakly biomineralized animals only, barely above a low metazoan grade of organization in the terminal Neoproterozoic (Ediacaran), and a later, early Cambrian burst of well skeletonized animals. Here we report new assemblages of primarily calcareous shelly fossils from upper Ediacaran (553–542 Ma) carbonates of Spain and Russia (Siberian Platform). The problematic organism Cloudina is found in the Yudoma Group of the southeastern Siberian Platform and different skeletal taxa have been discovered in the terminal Neoproterozoic of several provinces of Spain. New data on the morphology and microstructure of Ediacaran skeletal fossils Cloudina and Namacalathus indicate that the Neoproterozoic skeletal organisms were already reasonably advanced. In total, at least 15 skeletal metazoan genera are recorded worldwide within this interval. This number is comparable with that known for the basal early Cambrian. These data reveal that the terminal Neoproterozoic skeletal bloom was a real precursor of the Cambrian radiation. Cloudina, the oldest animal with a mineralised skeleton on the Siberian Platform, characterises the uppermost Ediacaran strata of the Ust’−Yudoma Formation. While in Siberia Cloudina co−occurs with small skeletal fossils of Cambrian aspect, in Spain Cloudina−bearing carbonates and other Ediacaran skeletal fossils alternate with strata containing rich terminal Neoproterozoic trace fossil assemblages. These finds treated together provide a possibility to correlate transitional Neoproterozoic– lower Cambrian strata around the world. Such a correlation concurs with available isotope and radiometric data and indicates that typical Ediacaran shelly fossils have not crossed the Precambrian–Cambrian boundary.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identifying the oldest larva of a myrmeleontiformian lacewing-a morphometric approach
Autorzy:
Herrera-Florez, A.F.
Braig, F.
Haug, C.
Neumann, C.
Wunderlich, J.
Hornig, M.K.
Haug, J.T.
Powiązania:
https://bibliotekanauki.pl/articles/2082151.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Insecta
Myrmeleontidae
Ascalaphidae
compression fossil
fossil larva
Cretaceous
Crato Formation
Brazil
Opis:
Neuroptera is one of the smaller ingroups of Holometabola, the ingroup of Insecta characterised by “complete” metamorphosis. Neuroptera comprises about 6000 species in the modern fauna, but appears to have been more diverse in the past. While adults distantly resemble certain moths or damselflies, the larval forms of Neuroptera are mostly fierce predators with prominent venom-injecting stylets. The most well-known of these larvae are probably those of antlions. Antlions and their closer relatives (silky lacewings, split-footed lacewings, ribbon-winged lacewings, spoon-winged lacewings, and owlflies) form a distinct monophyletic ingroup of Neuroptera, Myrmeleontiformia, hence the antlion-like forms. The fossil record of antlion-like larvae dates back far into the Cretaceous; many forms are known by exceptionally wellpreserved specimens entrapped in amber. The oldest fossil record of a neuropteran larva (not an antlion-like form) comes from Lebanese amber. Interestingly, the supposedly oldest record of an antlion-like larva is preserved in rock and comes from the famous Lower Cretaceous Crato Formation. We re-evaluate this fossil based on high-resolution composite photography. Due to the non-availability of many key characters, standard procedures for identifying the specimen to a more narrow ingroup remains challenging. Therefore, we used a morphometric approach. A combination of non-metric multidimensional scaling (NMDS), parallel coordinate plots and discriminant function analysis indicates that the fossil is a representative of the group Ascalaphidae (owlflies) + Myrmeleontidae (antlions). We discuss implications of this result for the fossil record of neuropteran larvae. These include the rather derived morphology of the oldest fossil larva of Myrmeleontiformia in contrast to previous expectations. Furthermore, fossils from soil dwellers can not only be expected to be found in amber, but also as compression fossils.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 2; 235-250
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new Y-shaped trace fossil attributed to upogebiid crustaceans from Early Pleistocene of Italy
Autorzy:
Pervesler, P
Uchman, A.
Powiązania:
https://bibliotekanauki.pl/articles/22896.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Psilonichnus
fossil
paleontology
Early Pleistocene
Upogebia
Parmaichnus
trace fossil
crustacean burrow
Pleistocene
Italy
Opis:
Y−shaped trace fossil (U−shaped upper part with a basal shaft), Parmaichnus stironensis igen. nov. et isp. nov. penetrates from a discontinuity surface cut in Early Quaternary mudstones in the Stirone Valley, Northern Italy. It is attributed to upogebiid decapod crustaceans. Parmaichnus differs from Psilonichnus by the presence of turning chambers in the upper part of the burrow. The turning chambers are considered to be an important taxonomic feature of upogebiid burrows. P. stironensis occurs together with Thalassinoides cf. paradoxicus (produced probably by callianassid crustaceans) and wide U−shaped pyritised cylinders (supposedly produced by balanoglossid hemichordates).
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 1; 135-142
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A large extinct marabou stork in African Pliocene hominid sites, and a review of the fossil species of Leptoptilos
Autorzy:
Louchart, A
Vignaud, P.
Likius, A.
Brunet, M.
White, T.D.
Powiązania:
https://bibliotekanauki.pl/articles/22950.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ethiopia
Ciconiidae
new fossil
Aves
fossil
Leptoptilos falconeri
Chad
Africa
Asia
Pliocene
paleontology
Opis:
New fossils of the family Ciconiidae from Pliocene hominid localities in Chad and Ethiopia are described, and several are shown to belong to Leptoptilos falconeri, originally known from the late Pliocene of the Siwalik Hills of India. Comparisons with all the hitherto known species of large Ciconiidae, and with an enlarged sample representing extant species, lead to a re−evaluation of some extinct taxa. Several synonymies are proposed, reflecting better the past diversity for this group. L. pliocenicus (Pliocene, Ukraine) is equivalent to L. cf. falconeri. Cryptociconia indica (late Pliocene, Siwalik Hills) belongs to Leptoptilos, and is probably either extant L. dubius or female L. falconeri. L. siwalicensis, from the same locality and also tentatively reported from the late Miocene of Northern Pakistan, is better referred to as Leptoptilini gen. et sp. indet. We consider the two following species as valid. L. titan (Pleistocene, Java) may be a late offshot of the lineage of L. falconeri. L. richae (late Miocene, Tunisia) is the size of L. crumeniferus, and is distinct from L. falconeri. Thus, L. falconeri remains the only ascertained extinct Pliocene species in the tribe Leptoptilini. It was a widespread “giant” marabou stork, in the Pliocene of southern Asia, as well as northern and eastern Africa where it coexisted with different Pliocene hominids, and probably eastern Europe. It weighed up to about 20 kg, reached 2 m in height, and had probably slightly reduced forelimbs. It became extinct by the end of the Pliocene. L. falconeri is an example of a biogeographical link at the species level between the African and Eurasian faunas in the Pliocene. The fossil record indicates the presence of at least one other lineage in Africa since the early Miocene, similar in size to the extant L. crumeniferus.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Features of the fossil record of evolution
Właściwosci kopalnego zapisu ewolucji
Autorzy:
Dzik, J.
Powiązania:
https://bibliotekanauki.pl/articles/20386.pdf
Data publikacji:
1991
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
fossil record
evolution
methodology
Opis:
Neither allopatric speciations nor extinctions of lineages are directly observable in the fossil record. This significantly reduces the value of inferred durations of taxa as a basis for studies on patterns of evolution. The ranges of taxa detected in rock strata are inevitably shorter than the real durations of lineages. Rates of evolution estimated by counting reported ranges of taxa therefore appear higher than they really were. Biometric studies of gradually evolving lineages indicate that the durations of ‘species’ (morphologies) were actually many times longer. Therefore, the ancestor-descendant relationships along monospecific lineages remain the most important subjects of study in evolutionary paleontology. A way, in which an ancestor-descendant hypothesis can be falsified, is presented.
Testowalność rekonstrukcji przebiegu ewolucji jest jednym z najważniejszych zagadnień paleontologii ewolucyjnej. Wiąże się bezpośrednio z fundamentalnym problemem, czy drzewo rodowe spełnia wymagania stawiane teoriom naukowym. Jego rozstrzygnięcie wymaga precyzyjnego i jednoznacznego sformułowania zasad tworzenia hipotez o powiązaniach ewolucyjnych. Nie wystarcza konstruowanie ich przy użyciu obciążonych subiektywizmem pojęć taksonu i pokrewieństwa krwi. Obiektywnie wyróżnialne są natomiast zespoły skamieniałości w obrębie prób paleontologicznych wykazujące ciągły i jednomodalny rozkład zmienności morfologicznej (odpowiadające neontologicznym fenonom Mayra), które obejmują na tyle krótki odcinek czasu geologicznego, że przemiany ewolucyjne nie deformują w nich rozkładu zmienności. Hipotezy o stosunku pokrewieństwa przodek-potomek dotyczące co najmniej dwu takich jednostek o różnym wieku geologicznym są możliwe do obalenia (sfalsyfikowania) na gruncie paleontologii.
Źródło:
Acta Palaeontologica Polonica; 1991, 36, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acanthodian fish trace fossils from the Early Devonian of Spitsbergen
Autorzy:
Wisshak, M
Volohonsky, E.
Blomeier, D.
Powiązania:
https://bibliotekanauki.pl/articles/21739.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
fish trail
trace fossil
Old Red Sandstone
fossil
Devonian
Acanthodii
Undichna
Spitsbergen
paleontology
Svalbard
Opis:
We describe and interpret Undichna septemsulcata isp. nov., from the fluvial Old Red Sandstone deposits of the Early Devonian Wood Bay Formation, of Northern Spitsbergen (Svalbard). Its delicate scratch pattern, comprising one unpaired median groove and three pairs of lateral grooves, all with a regular in−phase sinusoidal wave pattern of equal wavelength, allow the reconstruction of the number, position and relative spacing of the fins. The comparatively high−amplitude median groove is attributed to the main propelling action of the tail or caudal fin, the inner pair of the lateral grooves to the action of the pelvic fins, and the low−amplitude outer set of duplicate grooves to bifurcated pectoral fins, respectively. The in−phase geometric pattern is explained by a distance between the unpaired fin (caudal or anal fin) to the pectoral fins corresponding to one wavelength and a position of the pelvic fins half way in between. The direction of movement and the mode of locomotion of the trace maker (a carangiform to ostraciiform type) are deduced. This analysis is leading to an acanthodian (possibly Diplacanthus) as the most probable trace maker. By being Pragian or early Emsian (Early Devonian) in age, according to vertebrate and palynomorph biostratigraphy, these specimens are among the world’s oldest trace fossils made by a vertebrate.
Źródło:
Acta Palaeontologica Polonica; 2004, 49, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New evidence for the protoconodont origin of chaetognaths
Autorzy:
Szaniawski, H
Powiązania:
https://bibliotekanauki.pl/articles/20936.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
phylogenesis
paleobiology
fossil
Conodonta
marine animal
protoconodont
Metazoan
Cambrian
chaetognath
Chaetognatha
body fossil
Opis:
An earlier hypothesis concerning the origin of chaetognaths from protoconodonts found additional support in new discoveries and in recent structural, chemical and molecular investigations. The new findings show that the head armature of protoconodonts was composed not only of grasping spines but also of much smaller spicules corresponding in size and shape to the chaetognath teeth. Grasping spines of protoconodonts were originally built mainly of an organic substance. Their original composition was changed by secondary phosphatisation. The thickest layer of the protoconodont spines was originally constructed of organic fibrils, similar to those in the corresponding layer of chaetognaths. Recent molecular investigations show that the chaetognath lineage separated in the early stage of metazoan radiation, which fits the presented hypothesis. Described are some previously unknown structural details of chaetognath grasping spines, including composition of the outer layer and the origin of their distinctive tips.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Echinoid burrow Bichordites monastiriensis from the Oligocene of NE Italy
Autorzy:
Bernardi, M
Boschele, S.
Ferretti, P.
Avanzini, M.
Powiązania:
https://bibliotekanauki.pl/articles/22207.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
echinoid burrow
Bichordites monastiriensis
Oligocene
Italy
trace fossil
fossil
paleontology
Bichordites
Upogebia
foredeep
geological setting
Opis:
Several specimens of trace fossil Bichordites monastiriensis were discovered in two shallow water Oligocene sandstone beds from Valsugana (Trentino, NE Italy) representing the oldest documented occurrence for this ichnospecies. They are grazing−crawling (pascichnion−repichnion) structures and are occasionally associated with enlarged structures that can be interpreted as resting traces (cubichnia) and assigned to the ichnogenus Cardioichnus. The resulting Bichordites–Cardioichnus compound trace fossil is here described for the first time. In the basal part of some specimens, skeletal remains of Eupatagus ornatus were found in life position. This founding enables to widen the spectrum of known Bichordites tracemakers. Exceptional conditions of preservation of one specimen extending in two beds recording different environmental conditions gave an opportunity to document the effects of various taphonomical histories on the preservation of this traces.
Źródło:
Acta Palaeontologica Polonica; 2010, 55, 3; 479-486
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New basal synapsid supports Laurasian origin for therapsids
Autorzy:
Liu, J
Rubidge, B.
Li, J.
Powiązania:
https://bibliotekanauki.pl/articles/21774.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
synapsid
Laurasia
therapsid
fossil
paleontology
China
Therapsida
Dashankou
Permian
fauna
Gansu province
tetrapod fossil
Opis:
The distant evolutionary ancestry of mammals is documented by a rich therapsid fossil record. While sphenacodontid synapsids are considered the sister−group of therapsids, the place of origin of therapsids is an enigma, largely because of a long standing morphological and temporal gap (Olson’s Gap) in their fossil record. We describe a new large predatory synapsid, Raranimus dashankouensis gen. et sp. nov., from the Middle Permian of Dashankou in China which has a unique combination of therapsid and sphenacodontid features. This specimen is of great significance asit is a basal therapsid which is the sister taxon to all other therapsids. The fact that it was found in association with Early Permian tetrapods (Anakamacops and Belebey) suggests that it is the oldest therapsid and provides the first evidence of therapsid−bearing rocks which cover Olson’s Gap. It further supports that therapsids may have had a Laurasian rather than Gondwanan origin.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 3; 393-400
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chaetognath grasping spines from the Upper Mississippian of Arkansas [USA]
Autorzy:
Doguzhaeva, L A
Mutvel, H.
Mapes, R.H.
Powiązania:
https://bibliotekanauki.pl/articles/23070.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
grasping spine
fossil
USA
protoconodont
organic spine
phosphatized fossil
morphology
Arkansas
ultrastructure
Chaetognatha
paleontology
chaetognath
Opis:
Previously unidentified tiny (about 0.5 mm in length), hollow, gently curved, serrated spines probably originally composed of horny, organic fibers from the Upper Mississippian (Middle Chesterian = Namurian A equivalent or lower Serpukhovian) of Arkansas (USA) are described, and their probable chaetognath affinities are discussed. The specimens are preserved in an oval accumulation (about 15 mm long and 6 mm wide) of approximately 200 specimens within a small (about 25 mm in length) phosphatic concretion. For comparison, the grasping spines of the Recent chaetognath Eukrohnia hamata were examined. The Arkansas specimens are named Eoserratosagitta serrata gen. et sp. nov., and this genus is assigned to the Phylum Chaetognatha. The Upper Mississippian spines are also compared with protoconodonts. This comparison supports the hypothesis that the chaetognaths may have existed in the Cambrian.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fossil freshwater sponges: Taxonomy, geographic distribution, and critical review
Autorzy:
PRONZATO, ROBERTO
PISERA, ANDRZEJ
MANCONI, RENATA
Powiązania:
https://bibliotekanauki.pl/articles/945634.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
porifera
spongillida
fossil record
morphotraits
palaeobiogeography
Opis:
Sponges are one of the most ancient animal phyla with about 8850 living species and about 5000 described fossil taxa. Most sponges are marine and live at all depths of all oceans. Freshwater bodies (lakes, rivers) are inhabited only by a small minority of species, ca. 240 (< 3%) comprising the order Spongillida (Demospongiae) most of which are able to produce specialized resting bodies to survive harsh terrestrial environmental conditions. This highly disproportionate ratio of marine and freshwater sponges is even more accentuated in the field of palaeontology with rare records reported up to the Miocene (< 0.4% of all known fossil sponges). Only a few fossil taxa were correctly supported by strong and convincing taxonomic morphotraits at genus and species level, thus we provide here an overview of fossil freshwater sponges focusing on their morphotraits and distribution in time and space. Each recorded taxon is described in detail following the modern taxonomy and nomenclature. All fossil data suggest a clear trend of long term conservative morphology in the evolutionary history of Spongillida, although some traits of Recent gemmules evolved in a wide array of adaptive morpho-functional novelties. The majority of accepted fossil species belongs to the cosmopolitan family Spongillidae. The genera Oncosclera and Potamophloios of the family Potamolepidae seem to have had, in the past, a much larger geographic range than today. A synthesis of fossil taxa morphotraits is also provided in an Appendix 1.
Źródło:
Acta Palaeontologica Polonica; 2017, 62, 3; 468-495
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New fossil triakid sharks from the early Eocene of Premontre, France, and comments on fossil record of the family
Autorzy:
Adnet, S
Cappetta, H.
Powiązania:
https://bibliotekanauki.pl/articles/21991.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Gomphogaleus
Galeorhinus
Early Eocene
fossil shark
paleontology
Triakidae
Premonte
Chondrichthyes
Eocene
France
new fossil
triakid shark
Opis:
During the last two decades, an abundant selachian assemblage has been collected from the late Ypresian (NP12) fossiliferous sands of Prémontré (Aisne, northern France) but has received little attention. Sharks of the family Triakidae (Carcharhiniformes) are particularly well represented and all are described and figured herein. Among them, two new species of the genus Galeorhinus are described: G. duchaussoisi sp. nov. and G. louisi sp. nov.; these are compared to the common Paleogene G. ypresiensis which is refigured. Another triakid taxon, the genus Gomphogaleus gen. nov., is described. Most of the triakids have been recorded elsewhere in the North Atlantic region, suggesting a wider distribution than expected for these small sharks during the Paleogene. The present paper updates the list of selachians from Prémontré, bringing the number of taxa from 19 to 33 (including 22 sharks and 11 batoids) and improving our knowledge of the ancient North Atlantic Ypresian selachian fauna. Despite this vastly improved record, it is clear that fossil data are still very incomplete and insufficient for calibrating phylogenetic hypotheses of living forms. Review of the Prémontré fauna shows that the Triakidae were much more diverse and broadly distributed than at present, suggesting that the limited distribution and low diversity of living forms is probably a recent phenomenon.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Palaeobiological and palaeoenvironmental significance of the Pliocene trace fossil Dactyloidites peniculus
Autorzy:
Uchman, A.
Pervesler, P.
Powiązania:
https://bibliotekanauki.pl/articles/21237.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Dactyloidites peniculus
geological setting
Neogene
Pliocene
fossil
gardening
marine flooding
paleobiology
paleoenvironment
stratigraphy
trace fossil
paleontology
systematics
ichnology
Opis:
The radial trace fossil Dactyloidites peniculus occurs in a deep tier in totally bioturbated shoreface sediments of Pliocene age in the Stirone Valley, N Italy, together with Thalassinoides isp. and Ophiomorpha nodosa. Long, narrow shafts running from centre of the radiating structure and abundant faecal pellets in the radial structure were discovered. The trace maker of D. peniculus, probably a polychaete, deposited the pellets deeply in the sediment, probably for reinforcement of the tubes and a gardening of microbes for feeding. This trace fossil exclusively occurs within a narrow horizon at the top of a shallowing−up section interpreted as a high−stand system tract, below a discontinuity surface capped by finer sediments. D. peniculus was formed in soft sandy sediments under stable conditions related to the latest phases of the highstand system tract. Therefore, it is a candidate for indication of similar environmental situations having a soft sandy, but stable sea floor.
Źródło:
Acta Palaeontologica Polonica; 2007, 52, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A symbiotic association of a boring polychaete and an echinoid from the Late Cretaceous of Germany
Autorzy:
Wisshak, M.
Neumann, C.
Powiązania:
https://bibliotekanauki.pl/articles/21643.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Germany
Cretaceous
Late Cretaceous
trace fossil
fossil
polychaete
Polychaeta
Spionidae
bioerosion
Maastrichtian
symbiotic association
echinoid
Caulostrepsis
Polydora
Echinocorys
Opis:
From the Early Maastrichtian white chalk of Rügen Island (N Germany), a specimen of the echinoid Echinocorys ovata featuring 27 boring traces of the ichnogenus Caulostrepsis is described. Individual traces are shallow to moderately deep U−shaped depressions and show distinct regeneration textures evidencing a syn−vivo infestation. All traces are located on the plastron between the peristome and periproct of the host echinoid, indicating an adaptation of the trace maker by choosing the most advantageous position of the specific host. The traces are attributed to the work of boring spionid polychaetes (Polydora complex), grounded on the close morphological resemblance with initial borings of Recent polydorids. This is the first evidence for a possible association of a boring polychaete not only with an echinoid but with an echinoderm in general. The symbiotic relationship was commensalistic in nature with the spionid probably taking advantage of organic matter resuspended by the echinoids locomotion and feeding activity and benefiting from effective shelter. For the host echinoid, the association was moderately harmful. The soft bottom environment of the chalk sea provided very limited hard substrate ecospace for settlers and bioeroders, available only in form of biogenic structures. Echinocorys was a dominant component of this benthic community and can be considered as a suitable host for symbiotic interactions because of its size and assumed longevity.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

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