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Piotr Mierzejewski, the Count of Calmont

 A Free Graptolite Researcher and a Rosicrucian Frater

 See also http://www.graptolite.net/

 I studied biology and geology at the University of Warsaw, and received my M.Sc. degree cum laude in zoology and palaeontology under Professor Adam Urbanek. My first papers were published in scientific journals during my studies. My first appointment after graduation was a stint as an assistant in the Museumof the Earth, Warsaw, where I carried out investigations on amber and its biologicalinclusions. Next, I was awarded the Doctor's degree in Biological Sciences at the Institute of Paleobiology, Polish Academy of Sciences, Warsaw. From 1974 till 1991 I worked at the Polish Academy of Sciences.

Currently, I am a Deputy Director General of the International Biographical Centre, Cambridge (UK) and a permanent co-worker of the Roman Kozlowski Institute of Palaeobiology, Pol. Acad. Sci., Warsaw, Poland.

I continue working in the noble field of palaeontology. My research interests are primarily in sessile graptolites and pterobranchs. I am interested in all aspects of the Hemichordata including their biology, palaeobiology, stratigraphy, evolution, systematics and ultrastructure. Moreover, my interests are also in various Ordovician and Silurian organic microfossils, e.g. jaws of polychaete annelids (scolecodonts), chitinozoans, "chitinous" hydroids, scyphozoans, melanosclerites and all acid-resistant problematica.

Since 1999 I am involved in revision of the Volume V (Graptolithina), Treatise on Invertebrate Paleontology, as a co-leading author of chapters devoted to pterobranchs (with Susan Rigby, Amanda J. Chapman, and Peter N. Dilly) and non-dendroid sessile graptolites (with Adam Urbanek).

 

MY RECENT PUBLICATIONS:

 

[in press] Cortical fibrils and secondary deposits in the periderm of the hemichordate Rhabdopleura (Graptholithoidea). With Cyprian Kulicki. - Acta Palaeontologica Polonica 48.

[in press] Autothecal morphs and dormancy in the camaroid graptolite Xenotheka. - Acta Paleontologica Polonica 48.

2002. Discovery of Pterobranchia (Graptolithoidea) in the Permian. - Acta Palaeontologica Polonica 47, 1, 169-175.

The fossil remains of a hemichordate exoskeleton, recognized as fragments of the stolons and their cyst-like swellings connected with the fusellar zooidal tubes, were derived by chemical isolations from Late Permian (Kazanian) mudstones of the Svalis Dome (central Barents Sea, Norway). These fossils, referred to as Diplohydra szaniawskii sp.nov., are the first undoubted representatives of the Class Graptolithoidea found in Permian deposits. The genus Diplohydra Koz這wski, 1959, known previously only from the Ordovician and originally established as a thecate hydroid taxon, is reinterpreted as an aberrant member of the Order Rhabdoleuroidea. This strange hemichordate, characterized by fusellar tubes distinctly narrower than stolon-like tubes and their swellings, reveals a certain degree of dimorphism in the stolon system. D. szaniawskii sp.nov. also displays some peculiar morphological features common to the Ordovician rhabdopleuroid genus Rhabdopleurites Koz這wski and the stolonoid genus Stolonodendrum Koz這wski.

 2001. New graptolite, intermediate between the Tuboidea and the Camaroidea. - Acta Palaeontologica Polonica

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 purely morphological intermediate between them. This finding supports Kozlowski's (1949) concept of a close phylogenetic relationship between the orders Tuboidea and Camaroidea.

2001. Graptolite-like fibril pattern in the fusellar tissue of Palaeozoic rhabdopleurid pterobranchs. With Cyprian Kulicki. - Acta Palaeontologica Polonica 46, 3, 349-366.

The fusellar tissue of Palaeozoic rhaboopleurid pterobranchs has been studied using the SEM techniques. The fibrillar material of Ordovician Kystodendron ex. gr. longicarpus and Rhabdopleurites primaevus exhibits a distinct dimorphism, comprising: (1) thinner wavy and anastomosing/branching fusellar fibrils proper, producing a tight three-dimmensional meshwork; and (2) long, more or less straight and unbranched cortical fibrils, sometimes beaded, and arranged in parallel. These fibrils are similar to fusellar and cortical fibrils of graptolites, respectively. Until now, dimorphic fibrils and their arrangement within fusellar tissue were regarded as unique characters of the Graptolithina. In general, the fibrillar material of these fossils is partially preserved in the form of flaky material (new term) composed of flakes (new term). Flakes are interpreted as flattened structures originating from the fusiol of several neighbouring tightly packed fibrils. A Permian rhabdopleurid, referred to as Gen. et sp. indet. A., reveals a fabric and pattern of fusellar tissue similar to that of both Ordovician rhabdopleurids but devoid (?) of cortical fibrils. The results presented here question views that: (1) substaniatl differencies in fabric and pattern of fusellat tissue exist between fossil pterobranchs and graptolites; and (2) the ultrastructure of pterobranch periderm has remained unchanged at least the Ordovician. The Palaeozoic rhabdopleurids investigated are closer ultrastructurally to graptolites than to contemporary pterobranchs.

2000. A graptolite nature of the Ordovician microfossil Xenotheka. - Acta Palaeontologica Polonica 45, 71-84.

Light microscopic, SEM and TEM investigations show that the periderm of the problematic Ordovician microfossil Xenotheka klinostoma Eisenack, 1937 is built of five layers: inner lining, endocortex, fusellum, ectocortex and outer lining. The outer lining is made of 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.

 2000. On the nature and development of graptoblasts. - Acta Palaeontologica Polonica 45, 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 (Quebec, 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 traces of layering. Hemiseptae and the transverse septum are derivatives of the inner lining of the graptoblast. The 'genera' Graptoblastus Koz這wski, 1949 and Graptoblastoides Koz這wski, 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.

 2000. An aberrant encrusting graptolite from the Ordovician of Estonia. - Acta Palaeontologica 45, 239-250.

An organic microfossil, Erecticamara maennili gen. et sp.n., superficially similar to some imprefectly preserved chitinozoans, is described as an aberrant camaroid graptolite from the Lower Ordovivian 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 appearance of microfusellat 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 s sclerotized diaphragm described in other camaroids. The fossil unites certain characters of cephalodiscid pterobranchs and camaroid graptolites but is not interpreted as a truly transient link between these two hemichordate groupes.

 

In preparation:

1). The morphology and fine structure of Melanostrophus fokini, an Ordovician enigmatic hemichordate. With A. Urbanek.

2). Convergence in sessile graptolites (Camaroidea, Dendroidea). With Joerg Maletz and Kate Saunders.

3). New camaroid graptolite from the Ordovician of 珸and, Sweden.

 

 

 

 

Contact Address:

Piotr Mierzejewski, the Count of Calmont

piotr@mierzejewski.edu.pl

C/o Institute of Palaeobiology, Polish Academy of Sciences

Ul. Twarda 51/55, 00-818 Warszawa, Poland

 

 

Mea Victoria In Cruce Rosea - Sub Umbra Alarum Tuarum Iehova

A. D. 2002 (Rosicrucian Year 3355)