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Neocucullograptinae n. subfam. (Graptolithina)-their evolutionary and stratigraphic bearing

100%

Urbanek A.

Acta Palaeontologica Polonica

|

1970

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tom 15

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nr 2-3

A description of the morphology and evolution of a group of Upper Silurian monograptids, suggested to constitute Neocucullograptinae n. subfam., and including Bohemograptus Přib., Neolobograptus n. gen. and Neocucullograptus n. gen. is given. Studies were based on material etched from the core of Mielnik on the Bug (Eastern Poland) deep boring, and partly on erratic boulders of Baltic origin. In Lower Ludlovian Neocucullograptinae n. subfam. were represented by Bohemograptus, which on the boundary with Upper Ludlovian acquired the capability to produce microfusellar tissue. Further evolution of Neocucullograptinae n. subfam. marked by appearance of specialized representatives of Upper Ludlovian Bohemograptus, Neolobograptus n. gen. and Neocucullograptus n. gen., was closely connected with the utilisation of this peridermal fabric. Last named forms constitute characteristic elements of graptolite fauna in the Siedlce Beds of the Polish Platformian Silurian, which enable subdivision of their lower member into 5 new graptolite zones. Occurrence of this fauna on other areas of Eastern and Central Europe is indicated. Nature of changes in graptolite fauna on the boundary of Lower and Upper Ludlovian is discussed, and the probable role of biotic factors in extinction of Graptoloidea is emphasized. Origin and tentative phylogeny of Neocucullograptinae n. subfam. are discussed and probable biological interpretation of observed changes suggested. Quantitative analysis of long-lasted Bohemograptus bohemicus (Barr.) lineage has been given, and on the base of available evidence, a discrimination of two temporal subspecies is substantiated. Eight representatives (species and subspecies) of the Neocucullograptinae n. subfam. are described in systematic part. Three species and one subspecies are new. Moreover, appendix comprises description of two new aberrant species of "Monograptus".

2

On generation and regeneration of cladia in some Upper Silurian monograptids

100%

Urbanek A.

Acta Palaeontologica Polonica

|

1963

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tom 08

|

nr 2

A description is given of the structure and evolution of Upper Silurian Linograptinae on the base of material etched by chemical treatment of core samples from deep-boring at Mielnik on Bug (eastern Poland) and from Baltic erratic boulders. Neodiversograptus n. gen., represented by N. nilssoni and N. beklemishevi n. sp., belongs to an earlier evolutionary phase of this subfamily . Their rhabdosomes are characterized by bipolar growth of thecae, for a sicular cladium is produced in addition to the primary branch (procladium). Linograptus posthumus with multiramous rhabdosomes, comprising several sicular cladia, most probably descends from such forms. The origin and phylogenetic relations within the Linograptinae are discussed. The bipolar rhabdosomes of Diversograptus and Neodiversograptus n. gen. in which two branches develop from the sicula in result of normal astogeny, are distinguished from bipolar ,,morphoses" - here described in Lobograptus scanicus parascanicus and Linograptus posthumus - which are produced in result of regeneration of monograptid colonies that had been broken off. These rhabdosomes are deprived of the sicula at the point of divergence of two thecal series. The regenerative forms differ fundamentally in their biological significance from bipolar forms, produced through normal astogeny, and obviously they cannot be "taxonomically ranked". An attempt is made to define the morphological laws that govern the processes of normal astogeny, of the regeneration of colonies and of the simultaneous growth of thecae on the various branches of one colony. Using the data now available on the astogeny and evolution of the Monograptidae, a tentative classification is given of the phylogenetic modifications of astogeny by distinguishing their succes sive stages. Several new terms and definitions are introduced relevant to details of structure and development of multiramous monograptids.

3

The problem of graptolite affinities in the light of ultrastructural studies on peridermal derivatives in pterobranchs

100%

Urbanek A.

Acta Palaeontologica Polonica

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1976

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tom 21

|

nr 1

The ultrastructure of the organic coenecium in living Cephalodiscus (Cephalodiscus) inaequatus (Andersson) studied with the transmission electron microscope reveals a fabric and pattern very similar to that recognized in living Rhabdopleura compacta (Hincks) by Dilly (1971). The same techniques used to study the ultrastructure of Jurassic Rhabdopleura kozlowskii Kulicki and Ordovician Rhabdopleurites primaevus Kozlowski indicate that the nature of the fibrous unit elements of the periderm and their characteristic pattern remain unchanged within the Pterobranchia, at least since the Ordovician. The results combined with those of previous studies on the ultrastructure of peridermal derivatives in graptolites (Towe & Urbanek, 1972; Urbanek & Towe, 1974, 1975), reveal a substantial difference at the submicroscopic level between the fusellar component of the periderm in the Pterobranchia and that of the Graptolithina. The presumed homology between fusellar tissues of both groups constitutes the main argument in Kozlowski's suggestion (1938, 1949, 1966a) of a close affinity between pterobranchs and graptolites. A reevaluation of his line of reasoning enables us to conclude that Kozlowski's main criterion of homology was the specificity of the structures involved. This requirement is not fulfilled at the ultrastructural level because of substantial differences in the nature of the unit elements and their pattern. Moreover, other data on the ultrastructural anatomy of graptolites (very early deposition of cortical tissue over juvenile thecae; presence of cortical deposits over the inner surface of thecae; simultaneous secretion of successive fuselli and corresponding layers of cortical tissue) contradict the mode of secretion of the graptolite skeleton as suggested in the classical Kozłowski hypothesis. In contrast to the independent origin of fusellar and cortical tissue suggested by Kozłowski, each being secreted by a different part of the body, the ultrastructural data are indicative of a uniform mode of secretion. A secretion of the entire periderm within an epithelial evagination - the perithecal membrane - appears to be more readily compatible with the ultrastructural studies. Substantial differences in fabric, pattern, and mode of secretion of fusellar extracellular tissues in pterobranchs and graptolites produce serious obstacles for homology between them. Accordingly, there is little reason to suggest an immediate phylogenetic relationship between pterobranchia and Graptolithina. The systematic position of the ratter group within the Bilateria remains an unresolved problem.

4

Studies on graptolites 1. Development and structure of Pristiograptus gotlandicus (Perner)

100%

Urbanek A.

Acta Palaeontologica Polonica

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1959

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tom 04

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nr 1

This paper describes the astogeny and structure of Pristiograptus gotlandicus (Perner), etched from Silurian erratic boulders. This species differs from typical pristiograptids in certain characters of the thecal aperture whose morphological significance is discussed.

5

Phyletic evolution of the latest Ludlow spinose monograptids

100%

Urbanek A.

Acta Palaeontologica Polonica

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1995

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tom 40

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nr 1

1-17

The spinose latest Ludlow (Ludfordian) graptolite Monograptus (Uncinatograptus) spineus is not related to the lobate-spinose monograptids of the late Wenlock. It developed independently as a result of phyletic evolution from hooded M. (U.) acer, M. (U.) protospineus sp. n. being a transient link. Cumulative effects of gradual and directional changes within this lineage resulted probably in feeding specializations that enabled separation of niches. Previously described M. (U.) acer and M. (U.) aculeatus are defined as chronosubspecies, the latter representing a more advanced stage of evolution. A biostratigraphic subdivision of late Ludfordian in graptolite facies is suggested.

6

Ultrastructure ot the sicula in the tuboid graptolite Kozlowskitubus erraticus (Kozlowski, 1983)

100%

Urbanek A.

Acta Palaeontologica Polonica

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1979

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tom 24

|

nr 4

The sicula of Kozlowskitubus erraticus has been examined with TEM. The upper portion ot prosicula is three-layered, the middle layer being a mesh. Its bottom consists of an attenuated, almost structureless membrane. The metasicula is made of strongly variable fuselli, built of fusellar and sheet tabric only (Dictyonema type ot fuselli). The evidence available indicates that mesh fabric is the main component in all discophorous and in part ot nematophorous prosiculae (structural type "A"). Only some nematophorous prosiculae are lacking the mesh component and therefore constitute structural type "B". The striking similarity ot the sicula described with the embryonal vesicle ot Rhabdopleura may not be evaluated until more becomes known on latter's ultrastructure.

7

The significance of graptoblasts in the life cycle of crustoid graptolites

100%

Urbanek A.

Acta Palaeontologica Polonica

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1983

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tom 28

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nr 3-4

Graptoblasts are small ovoid bodies with a flat lower, and a convex upper, wall, the latter provided with a costulation having a fusellar aspect. First found as isolated bodies associated with graptolite remains, graptoblasts were later recognized as a constituent of crustoid colonies (Kozłowski 1949, 1962). Their biological role remains largely enigmatic. The view that graptoblasts were formed within the authothecae is rejected and a conclusion is advanced that graptoblasts were closed, resting terminal portions of the stolothecae, housing encysted dormant zooids. They may be compared with the resting terminal zooids in Rhabdopleura and with the hibernacula of ctenostome bryozoans. Graptoblasts provided an adaptation allowing the species to survive the periods of adverse conditions when the rest of the colony disintegrated. One could hypothesize that after germination the graptoblasts produced small propagules ejected through a narrow cryptopyle and forming new colonies after they settled on the substrate.

8

Współczesne niekonwencjonalne teorie ewolucji

100%

Urbanek A.

Kosmos

|

1991

|

tom 40

|

nr 2-3

9

An attempt at biological interpretation of evolutionary changes in graptolite colonies

100%

Urbanek A.

Acta Palaeontologica Polonica

|

1960

|

tom 05

|

nr 2

Problems of morphological organization in graptolite colonies are discussed and suggestions made as to the supposed genetic mechanisms of their evolution. The regular astogenetic succession of thecae is interpreted as an effect of morphophysiological gradients, The spreading of new thecal types in forms constituting successive evolutionary stages of a lineage are believed to be manifestations of the penetrance and expressivity of respective genetic factors.

10

Historia wielogalazkowych graptolitow poznego syluru dowodzi, ze efekty makroewolucyjne moga byc rezultatem zmian zachodzacych w pojedynczej linii ewolucyjnej

100%

Urbanek A.

Działalność Naukowa PAN. Wybrane Zagadnienia

|

1998

|

tom 05

79-80

11

Współczesne poglądy na makroewolucję

100%

Urbanek A.

Kosmos

|

1987

|

tom 36

|

nr 3

12

On the morphology and evolution of the Cucullograptinae (Monograptidae, Graptolithina)

100%

Urbanek A.

Acta Palaeontologica Polonica

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1966

|

tom 11

|

nr 3-4

A description is given of the structure, astogenetic development and evolution of the Upper Silurian Cucullograptinae. It is based on the material contained in the core samples from the Mielnik on the Bug (Eastern Poland) deep-boring and from the Baltic drift. The graptolites were prepared by dissolving the limestone and marly matrix in hydrochloric acid. For detailed study the specimens were bleached. The stratigraphic position and significance of the fauna investigated are discussed. The main trend in the evolution of sicula consists in its simplification and is interpreted as due to foetalization. In contrast with sicula, the evolution of thecae displays progressive changes which primarily consist in the development of apertural apparatus, connected, in most lines, with the elaboration of its secondary asymmetry. The biological significance of this pattern of evolution of thecal characters is discussed. The Cucullograptinae supply convincing evidence for the distal introduction of phylogenetic novelties which makes up a prevailing mode of evolutionary changes of astogeny in this group of moriograptids. Problems, related to the mechanisms of evolution and organization of graptolite colonies are discussed. Using the data, now available, tentative phylogenetic relationships within the group are established. An attempt is made to show some implications of these data in the problem of origin of the Cucullograptinae. Fourteen representatives (species and subspecies) of the Cucullograptinae are described in the systematic part. Four species and two subspecies are new.

13

Ultrastructure of microfuselli and the evolution of graptolite skeletal tissues

100%

Urbanek A.

Acta Palaeontologica Polonica

|

1976

|

tom 21

|

nr 4

Ultrastructure of microfusellar tissues has been studied in Neocucullograptus kozlowskii, and compared with that in normal fuselli. Microfusellar tissue is composed of both fully developed and reduced microfuselli. The former consists of the fusellar and the cortical components and may pass into reduced microfuselli due to skipping the fusellar phase of secretion. This demonstrates a possible mechanism of the transition from the fusellar to the cortical tissue and sheds some light on principles governing the morphogenesis of graptolite skeletal tissues. Formation of particular fabrics and patterns was determined by control of a certain innate potential of secretory cells. Modes of changes in this control are identified and a working hypothesis concerning the evolution of graptolite skeletal tissues is advanced.

14

XXIII Zgromadzenie Ogólne Międzynarodowej Unii Nauk Biologicznych (IUBS) (Canberra, 16-20 X 1988)

100%

Urbanek A.

Kosmos

|

1990

|

tom 39

|

nr 2-3

15

Significance of ultrastructural studies for graptolite research

100%

Urbanek A.

Acta Palaeontologica Polonica

|

1978

|

tom 23

|

nr 4

Among many aspects of ultrastructural studies on graptolites of crucial significance is the interpretation of their mode of secretion of periderm. This might contribute to solving the phylogenetic problems and to a be ter understanding of the development and the function of the colony. A membrane model of secretion of the graptolite periderm is discussed in some details and compared with alternative interpretations suggested by Andres (1977) and Crowther and Rickards (1977). Both interpretations are evaluated in respect to the entirety of the existing data. A generalized explanation of cortical bandages or ribbons formation due to the presence of the perithecal membrane is offered.

16

Some remarks on colony organization in graptolites

100%

Urbanek A.

Acta Palaeontologica Polonica

|

1978

|

tom 23

|

nr 4

Implications of the presence of perithecal membrane for understanding the degree of integration of graptoloid colonies is discussed. In contrast to Kirk's (1975) opinion that graptoloid colonies can be thought of as a kind of super-individual, a view is advanced that most of morphogenetic functions were delegated to particular zooids. The share of common colonial struotures is too small to consider graptoloid colonies as single individuals. Irregular and localized secretion speaks against the concept of rhabdosome being a preciselly controlled counting device.

17

Studies on graptolites II. On the development and structure of graptolite

100%

Urbanek A.

Acta Palaeontologica Polonica

|

1959

|

tom 04

|

nr 3

This paper describes the astogeny and structure of Gymnograptus linnarssoni (Moberg) and G. retioloides (Wiman) and also the structure of Gymnograptus sp. The material has been etched from erratic boulders of Scandinavian origin, which are of Middle Ordovician age. The systematic position of the genus Gymnograptus is discussed.

18

Oligophyly and evolutionary parallelism: A case study of Silurian graptolites

100%

Urbanek A.

Acta Palaeontologica Polonica

|

1998

|

tom 43

|

nr 4

549-572

Oligophyly may be defined as a restrictive factor in evolution leading to minimization of the number of phyletic lines owing to an occasional reduction by means of mass extinction as well as to their recovery from scanty survivors. The monophyletic origin of the vast majority of taxa finds its explanation in this succession of events, namely in the diversity reduction (DR) - rediversification (RD) sequence. In turn, the recovery from a few or a single ancestral species (near-monophyly or monophyly) causes a number of consequences for the evolution of emerging new taxa. They produce a particular class of systematic groups called genealogical domains. Such groups display an exceptionally close affinity and a similar evolutionary potential exhibited i-.e. an abundant parallelism. In other words, the paucity of ancestry (oligophyly) explains why both the monophyletic origin and evolutionary parallelism are such common features of the phylogeny in most fossil groups. Parallelism is caused by the similarity of apomorphic tendencies (known as 'underlying synapomorphy' in phylogenetic systematics), which are among the most characteristic features of evolution within a genealogical domain. It is now evidenced that the vast majority of Late Silurian monograptid faunas are descendants of only two species - survivors from the severe lundgreni Event. Numerous cases of heterochronic parallelism and evolutionary repetitions observed within the repertoire of the Late -Silurian monograptid faunas may be explained as a far reaching effect of oligophyly. Each ancestral species established its own genealogical domain displaying certain apomorphic tendencies. The same is true for the monophyletic origin and early radiation of Llandovery monograptids. Whilst graptolites provide numerous graphic examples substantiating the oligophyly concept, it is clear that the phenomena discussed are of a much more general nafure.

19

Morphogenetic gradients in graptolites and bryozoans

100%

Urbanek A.

Acta Palaeontologica Polonica

|

2004

|

tom 49

|

nr 4

Despite independent evolution of coloniality in hemichordates and bryozoans, their colonies show common features. In both instances colony is a genet or clonal system composed of zygotic oozooid and a number of blastozooids (= modules) integrated by physical continuity of tissues, sharing a common genotype and subject to common morphogenetic control. In some groups of graptolites and bryozoans, colonies display a regular morphological gradient. Simple graptoloid and bryozoan colonies consist of a proximal zone of astogenetic change and a distal zone of astogenetic repetition. Observed morphological gradient may be attributed to diffusion, along the colony axis, of a morphogen produced by the oozooid; in the zone of astogenetic change the morphogen is above certain threshold level and drops below it in the zone of astogenetic repetition. This model is supported by observations on regeneration of fractured graptoloid colonies. Regenerative branch never displays astogenetic change. The same rule is valid for regeneration of fractured bryozoan colonies. While the early astogeny of simple bryozoan colonies may be explained within the framework of the gradient theory, the late astogeny of more complex ones involves multiple succession of zones of change and repetition, without analogy in astogeny of graptoloids. Thus, late astogeny in bryozoan colonies may be controlled by cyclic somatic/reproductive changes, probably independent of the primary morphogen. Evolutionary changes in the graptoloid colonies involve both the spreading of the novelties over a greater number of zooids (penetrance) and an increase in the degree of phenotypic manifestation of a given character (expressivity). In the phylogeny of bilaterian colonies morphogenetic gradient probably originated as a sort of a side effect of sexual process leading to the appearance of the oozooid. The latter contaminated the neighbouring blastozooids with the products of its own morphogenesis. The resulting morphogenetic gradient could be used by selective forces to produce various effects of adaptive significance. Morphogens responsible for patterning of bilaterian colonies are probably related to the products of genes responsible for the anteroposterior control of embryos in all solitary Bilateria (Hox, zootype genes).

20

Pedigree Advance Formula - nowa jakosc w zywieniu psow

75%

Urbanek A.

Magazyn Weterynaryjny

|

1996

|

tom 05

|

nr 1

57-58

Ograniczanie wyników

Neocucullograptinae n. subfam. (Graptolithina)-their evolutionary and stratigraphic bearing

On generation and regeneration of cladia in some Upper Silurian monograptids

The problem of graptolite affinities in the light of ultrastructural studies on peridermal derivatives in pterobranchs

Studies on graptolites 1. Development and structure of Pristiograptus gotlandicus (Perner)

Phyletic evolution of the latest Ludlow spinose monograptids

Ultrastructure ot the sicula in the tuboid graptolite Kozlowskitubus erraticus (Kozlowski, 1983)

The significance of graptoblasts in the life cycle of crustoid graptolites

Współczesne niekonwencjonalne teorie ewolucji

An attempt at biological interpretation of evolutionary changes in graptolite colonies

Historia wielogalazkowych graptolitow poznego syluru dowodzi, ze efekty makroewolucyjne moga byc rezultatem zmian zachodzacych w pojedynczej linii ewolucyjnej

Współczesne poglądy na makroewolucję

On the morphology and evolution of the Cucullograptinae (Monograptidae, Graptolithina)

Ultrastructure of microfuselli and the evolution of graptolite skeletal tissues

XXIII Zgromadzenie Ogólne Międzynarodowej Unii Nauk Biologicznych (IUBS) (Canberra, 16-20 X 1988)

Significance of ultrastructural studies for graptolite research

Some remarks on colony organization in graptolites

Studies on graptolites II. On the development and structure of graptolite

Oligophyly and evolutionary parallelism: A case study of Silurian graptolites

Morphogenetic gradients in graptolites and bryozoans

Pedigree Advance Formula - nowa jakosc w zywieniu psow