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1
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Graptolite nature of the Ordovician microfossil Xenotheka

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
2000
|
tom 45
|
nr 1
71-84
Light microscopic, SEM and TEM investigations show that the periderm of the problematic Ordovician organic microfossil Xenotheka klinostoma Eisenack, 1937 is built of five layers: inner lining, endocortex, fusellum, ectocortex and outer lining. The outer lining is made of a previously unknown material named here verrucose fabric. The outer lining was presumably an adaptation which aided survival through periods of unfavourable conditions. The general morphology of the test as well as of the fusellar structure of the wall indicate that Xenotheka is an aberrant camaroid graptolite. This finding thus extends the upper stratigraphic limit of the order Camaroidea from the early Arenig to Llandeilo.
2
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Encrusting graptolites from the Mulde Beds of Gotland

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1988
|
tom 33
|
nr 3
Two species of the Crustoidea (Bulmanicrusta latialata Kozłowski, Urbanekicrusta reversa Mierzejewski) and three species of the Tuboidea (Kozlowskitubus erraticus (Kozłowski), Epigraptus kozlowskii Mierzejewski and E. ex gr. bilinguis (Kozłowski) are reported from upper part of the Mulde Beds (upper Wenlock) of Gotland. Up to the present time, the first four species have been known from glacial boulders of Poland exclusively.
3
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On the nature and development of graptoblasts

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
2000
|
tom 45
|
nr 3
227-238
Two specimens of graptoblasts, which provisionally may be assigned to 'Graptoblastoides' sp. and 'Graptoblastus' sp., are described from the early Llandovery of Anticosti Island (Québec, Canada). Previous reports of Silurian graptoblasts were restricted to a single specimen from Poland. One of the new specimens is morphologically distinct from all known graptoblasts - both chambers of the inner cavity contain numerous incomplete septae, here referred to as hemiseptae. SEM observations show distinct two-layered character of the transverse septum, whereas the hemiseptae show no trace of layering. Hemiseptae and the transverse septum are derivatives of the inner lining of the graptoblast. The 'genera' Graptoblastus Kozłowski, 1949 and Graptoblastoides Kozłowski, 1949 are interpreted as stages in graptoblast development, and are consequently replaced by the purely descriptive terms 'graptoblastus' and 'graptoblastoides'. The following stages of graptoblast development are recognized: (1) pre-graptoblastoides stage, (2) early graptoblastoides stage, (3) late graptoblastoides stage, (4) early graptoblastus stage, and (5) late graptoblastus stage. A graptoblast s.s. (i.e., devoid of a blastotheca) and its developmental stages strikingly resemble the earliest stages of the astogeny of the modern pterobranch Rhabdopleura. These observations support A.Urbanek's hypothesis that zooids became encysted within graptoblasts and rejuvenated by a process of metamorphosis.
4
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New aberrant sessile graptolites from glacial boulders

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1985
|
tom 30
|
nr 3-4
Two new aberrant sessile graptolites from glacial boulders are described. The Silurian form, Urbanekicrusta reversa gen. et sp.n., is interpreted as a crustoid (hormograptid?) graptolite, whereas the Ordovician (?), Maenniligraptus ursulae gen. et sp.n., represents presumably an unknown order of Graptolithina.
5
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Tuboid graptolites from erratic boulders of Poland

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1978
|
tom 23
|
nr 4
Cyclograptidae (= Idiotubidae) are described from the Ordovician to Silurian erratic boulders of Poland. Some problems involved in tuboid taxonomy and colony organization are considered. One new genus (Kozlowskitubus gen.n.) and three new species (Epigraptus eisenacki sp.n., E. kozlowskii sp.n., Dendrotubus bulmani sp.n.) are erected. Names Idiotubus Kozłowski, 1949, and Idiotubidae Kozłowski, 1949, were recognized for junior synonyms of Epigraptus Eisenack, 1941, and Cyclograptidae Bulman, 1938, respectively.
6
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Nature of graptovermids (Graptolithina)

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1988
|
tom 33
|
nr 3
Graptovermids are redefined as resting terminal portions of unknown encrusting graptolites stolothecae. Presumably, their biological significance was an adaptation allowing to survive the periods of unfavourable or adverse conditions. SEM observations are made on Graptovermis intestinalis Kozłowski, 1949 from the lower Ordovician of Öland (Sweden).
7
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Algal nature of the Ordovician presumed polychaete eggs

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1991
|
tom 36
|
nr 1
An enigmatic Ordovician organic microfossil, previously interpreted as polychaete eggs accumulation, is reexamined with ТЕМ methods and reinterpreted as presumably blue-green algae rests.
8
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Cephalodiscus-type fibrils in the graptoblast fusellar tissue

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1984
|
tom 29
|
nr 3-4
The fusellar tissue of an Ordovician graptoblast has been studied with ТЕМ. It was found that it is solely composed of Cephalodiscus-type fibrils, unknown hitherto in graptolites. The fusellar tissue of the studied specimen has more in common with recent pterobranchs than with graptolites.
9
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Molting of the jaws of the early peleozonic eunicida (Annelida, Polychaeta)

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1978
|
tom 23
|
nr 1
Pharate jaws of the Ordovician and Silurian Eunicida have been studied under a scanning electron microscope and the conjecture has been formed that the molting of jaws in the Early-Paleozoic Eunicida took place many times in the process of their ontogeny and was not necessarily connected with their growth. The cases of jaw replacement, observed so far in the fossil Polychaeta, were of the nature of a cyclic physiological regeneration, whereas the replacement of jaws in Recent forms is a reparative regeneration. The specific name Mochtyella multilamellata Szaniawski 1970 is a simultaneously published synonyme of the name Mochtyella fragilis Szaniawski 1970, accepted as a valid.
10
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Estoniocaulis Obut et Rötsk, 1958 and Rhadinograptus Obut, 1960 are not graptolites

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1991
|
tom 36
|
nr 1
Estoniocaulis jaervensis Obut et Rötsk, 1958 and Rhadinograptus jurgensonae Obut, 1960 from the Silurian of Estonia are redescribed. It is stated that both taxa, regarded so far as inocaulid and dithecoid graptolites respecively, have nothing in common with the Graptolithina. These forms are treated as incertae sedis fossils (algae?).
11
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Pterobranchites Kozłowski, 1981- an aberrant graptolite?

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
1984
|
tom 29
|
nr 1-2
The periderm of Ordovician Pterobranchites antiquus Kozłowski, 1967 has been examined with SEM. Four components have been recognized within the thecal wall: outer lining, cortex, fusellum and inner lining. The cortex material is composed of thick, straight, unbranched fibrils arranged in several layers as in cortical layer of the graptolite periderm, p. antiquus, previously referred to cephalodiscid pterobranchs, is identified as an aberrant graptolite of uncertain taxonomic position.
12
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An aberrant encrusting graptolite from the Ordovician of Estonia

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
2000
|
tom 45
|
nr 3
239-250
An organic microfossil, Erecticamara maennili gen. et sp. n., superficially similar to some imperfectly preserved chitinozoans, is described as an aberrant camaroid graptolite from the Lower Ordovician Kunda Stage, Aluoja Substage, of the Tallinn area, North Estonia. Its elongated, bottle-shaped or subconical thecae, interpreted as autothecae, are differentiated into a broader proximal part (camara), provided with a convex, rarely flat, bottom, and a narrower distal one (collum), devoid of any kind of apertural processes. The wall of the fossil is made of the fusellar tissue; irregularly distributed oblique sutures of fuselli are not arranged in a zigzag line. A sudden change of fuselli width leading to an appearence of the microfusellar tissue is sometimes observed in the distal part of the tube. The presence of primitive cortex (paracortex? pseudocortex?) is suggested. Robust, elongated vesicles are found inside two autothecae and interpreted as a dormant structure, tentatively compared with cysts of crustoid graptolites or a blastocrypt of graptoblasts. Its upper wall is situated between the camara and collum and looks like a sclerotized diaphragm described in other camaroids. The fossil unites certain characters of cephalodiscid pterobranchs and camaroid graptolites but is not interpreted as truly transient link between these two hemichordate groups.
13
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A new graptolite, intermediate between the Tuboidea and the Camaroidea

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
2001
|
tom 46
|
nr 3
A new tuboid graptolite, Camarotubus graptocamaraeformis gen. et sp.n., is described from a calcareous erratic boulder of middle Ordovician (Caradoc?) age from Poland. This encrusting form combines characters of both the tuboid and the camaroid graptolites, and is regarded as a purely morphological intermediate between them. This finding supports Kozłowski's (1949) concept of a close phylogenetic relationship between the orders Tuboidea and Camaroidea.
14
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Autothecal morphs and dormancy in the camaroid graptolite Xenotheka

100%
Mierzejewski P.
Acta Palaeontologica Polonica
|
2003
|
tom 48
|
nr 1
The camaroid graptolite Xenotheka klinostoma Eisenack, 1937 is described from the lower Llanvirn limestones of Gilbergabrottet, northern Öland, Sweden. Two distinct autothecal morphs are recognized: (1) normal morph (described for the first time), i.e. an autotheca with an unsculptured outer surface, devoid of both an outer lining and autothecal occlusion, and inhabited by an active zooid; and (2) sealed morph, i.e. an autotheca coated and occluded, provided with a sculptured outer lining made of a unique verrucose fabric, and inhabited by an inactive or dormant zooid. In addition, the existence of a hypothetical (3) unsealed morph or re−opened autotheca, devoid of an autothecal occlusion but provided with an outer lining, and inhabited by a reactivated zooid, is predicted. The sealed morphs may represent an adaptation which allowed their inhabitants to survive adverse conditions. The outer lining of Xenotheka is compared with a peculiar outer membrane found in the modern hemichordate Rhabdopleura, from the intertidal zone of Fiji, and with camaroid extracamaral tissue.
15

Arboryści z certyfikatem

75%
Mierzejewski P.
Drwal. Pismo Przedsiębiorców Leśnych
|
2014
|
nr 02
16

Jak zostać arborystą?

75%
Mierzejewski P.
Drwal. Pismo Przedsiębiorców Leśnych
|
2013
|
nr 09
17
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Ultrastructure of the jaws of the fossil and recent Eunicida (Polychaeta)

63%
Mierzejewska G., Mierzejewski P.
Acta Palaeontologica Polonica
|
1978
|
tom 23
|
nr 3
The ultrastructure of the jaws of Ordovician, Silurian, Permian and Recent Eunicida (Polychaeta) have been studied by transmission and scanning electron microscopy. Primary and secondary zones have been distinguished in the ultrastructure of the jaws. The primary zone is formed of the pharyngeal cuticle containing an orthogonal network of collagen fibrils, while the secondary zone, underlying the primary one, is developed of inner part of the pharyngeal cuticle devoid of a regular network of collagen fibrils. The two zones are pierced by microvilli. The jaws of placognath Eunicida are structured of the primary zone only. The Eunicida with highly organized jaw apparatus have a strongly developed secondary zone underlying the primary one. A preliminary correlation of evolutionary changes in the anatomy and ultrastructure of the jaws of Eunicida has been conducted. It has also been shown that the ultrastructural studies of the scolecodonts were not very useful for taxonomic purposes.
18
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Receptaculites abhorrens n. sp. from the Upper Devonian of Poland

63%
Mierzejewska G., Mierzejewski P.
Acta Palaeontologica Polonica
|
1973
|
tom 18
|
nr 2
Receptaculites abhorrens n.sp. from the Upper Frasnian of Lower Silesia is described. The species combines in a mosaic fashion the characteristics of the Receptaculites Deshayes and Ischadites Murchison.
19
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Xenognath type of polychaete jaw apparatuses

63%
Mierzejewski P., Mierzejewska G.
Acta Palaeontologica Polonica
|
1975
|
tom 20
|
nr 3
A new type of ?eunicid jaw apparatuses designated xenognath is described; it differs from previously known jaw apparatuses in having the denticulated ridges in compound jaws perpendicular to apparatus axis. It includes the Ordovician genus Archaeoprion nov., assigned to a new family Archaeoprionidae.
20
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The ultrastructure and building of graptolite dissepiments

63%
Urbanek A., Mierzejewski P.
Acta Palaeontologica Polonica
|
2009
|
tom 54
|
nr 2
243-252
Dissepiments or connecting bars between adjacent stipes in rhabdosomes of dendroid graptolites were studied by means of electron microscopy (SEM and TEM). The material, chemically isolated from rock matrix, originating from the Ordovician of Estonia and glacial boulders of Baltic origin found in Poland, is assigned provisionally to the genus “Dictyonema” sensu lato. Early growth stages of dissepiments are made only of the fusellar component. Older dissepiments are composed of the central core and the outer envelope: the central core is made of rather irregularly arranged growth units made of the fusellar tissue, whereas the outer envelope has a distinct cortical appearance. TEM observations indicate that the fusellar component is made of both typical fusellar and microfusellar tissues (the latter with complete and reduced microfuselli). The cortical component of dissepiments is made both of dependent and independent cortex. The opinion is advanced that the dissepiments were constructed externally by the mortaring activities of zooids, similar to that of Recent Cephalodiscus. Our observations indicate that bizooids were most probable dissepiment constructors. These results, in general, does not support earlier opinions that dissepiments are made of cortical tissue acquiring a fusellar aspect in some cases, and that dissepiments were produced by the extrathecal membrane surrounding the rhabdosome.
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