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Long-term shoreline shifts on continental blocks during the Bajocian: an updated interpretation based on synthetic stratigraphical and palaeogeographical developments on regional scales

Ruban Dmitry A., Sallam Emad S.

Geologos

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2019

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Vol. 25, No. 1

43--50

EN

Available reconstructions of Jurassic global sea level changes differ and are in need of an update. New stratigraphical charts and palaeogeographical developments for a number of large continental blocks or their portions of these (e.g., Germany, India, northeast Africa, northwest Australia, the Russian Platform and western Siberia) reveal regional long-term shoreline shifts (i.e., transgressions and regressions) during the Bajocian Stage (168.3–170.3 Ma). A comparison of these allows to document only a single coherent feature, namely the earliest Bajocian transgression, in the majority of the continental blocks considered. Undoubtedly, this event was triggered by a eustatic rise. However, long-term shoreline shifts were either weak to absent or differed between the blocks during almost the entire Bajocian, thus providing evidence of the apparent stability of global sea level and the importance of regional tectonic activity as a control mechanism on particular transgressions and regressions. Interestingly, it appears that the earliest Bajocian eustatic rise was a constituent of a long-term eustatic pattern; the nature of this event has yet to be fully understood. Generally, the findings presented here are in better agreement with Anthony Hallam’s view of Jurassic eustasy and question some other global sea level reconstructions.

2

Detailed biostratigraphic scales as based on the palaeobiogenetical approach (an example of the Upper Bajocian – Lower Bathonian ostracod scale of the Russian Platform)

Shurupova Y. A., Tesakova E. M.

Volumina Jurassica

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2017

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Vol. 15, no 1

121--138

EN

Two new species of ostracods of the family Progonocytheridae Sylvester-Bradley Camptocythere (C.) lateres Tesakova et Shurupova, sp. nov. and C. (C.) angustius Tesakova et Shurupova, sp. nov. from the Michalskii and Besnosovi ammonite zones (Upper Bajocian – Lower Bathonian, Middle Jurassic) of the Sokur section (Saratov) are described. The changes in ontogenesis in the phylogeny of Camptocythere (C.) lateres Tesakova et Shurupova in the stratigraphical interval corresponding to the Palaeocytheridea kalandadzei ostracod Zone, and especially to the beds with C. (C.) lateres, have been studied. The levels of the change in the predominant type of sculpture (corresponding to evolutionary boundaries) are recognized in the sculpture development among the adult representatives of the species in its phylogeny. This palaeobiogenetic (heterochrony) approach allows subdivision of the beds with C. (C.) lateres into three stratigrapical intervals characterized by changes in the type of sculpture.

3

A preliminary report on dinosaur track assemblages from the Middle Jurassic of the Imilchil area, Morocco

Gierliński G. D., Menducki P., Janiszewska K., Wicik I., Boczarowski A.

Geological Quarterly

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2009

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Vol. 53, No 4

477-482

EN

Dinosaur tracks are reported from three new localities near Imilchil, in the Central High Atlas of Morocco. New dinosaur track assemblages are recognized in Bathonian and Bajocian beds. The Bathonian track assemblage comprises theropod, sauropod and ornithopod footprints. The Bajocian deposits contain a sauropod-thyreophoran track assemblage.

4

Storm deposits: evidence of event sedimentation in the Bajocian of the Central High Atlas, Morocco

Alt Addi A.

Volumina Jurassica

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2008

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Vol. 6, no. 1

23-32

EN

Storm beds interbedded with marls, claystones and beds of nodular to undulose bioclastic limestones have been recognized in the Central High Atlas of Morocco. These provide the first evidence of event sedimentation in the Bajocian of the area. The outcrops studied are included in the Agoudim and Tazigzaout formations in the center of the basin, and are parts of the Bin El Ouidane Group at the margins of the basin. The storm deposits comprise calcarenites and bioclastic packstones-grainstones. These beds have symmetrical wave-ripples at their tops and an internal structure of hummocky cross-stratification. They are considered to have been formed by tropical storms and hurricanes. Multiple reworking and winnowing of siliciclastic or bioclastic material by oscillatory currents related to storm and to currents resulting from storm/tide interactions is inferred. Bed features are the most important evidence in favour of a palaeobathymetric interpretation of related pelagic sediments, with calcareous tempestites representing episodic resedimentation, mainly coincident with relative sea-level falls during which major storm waves affected the sea bottom. This interpretation is in agreement with the regional palaeogeography and is further supported by evidence of Jurassic storm-controlled sedimentation in adjacent Mediterranean basins.

5

The carbon and oxygen isotope records of Upper Bajocian-Bathonian calcareous fossils from the Polish Jura Chain

Wierzbowski H., Joachimski M.

Volumina Jurassica

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2006

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Vol. 4, no. 1

220-222

EN

A collection of stratigraphically well-dated calcitic and aragonitic fossils (belemnites, ammonites, nautiloids and oysters), derived from Upper Bajocian - Upper Bathonian clays from the Polish Jura Chain (central Poland), were studied for oxygen and carbon isotopes. The preservation state of the shell material was investigated by means of cathodoluminescence microscopy, trace element geochemistry and X-ray diffraction. Palaeotemperatures calculated from the oxygen isotope composition of calcitic shells (belemnites and oysters) are similar to each other despite the significant spread in 18O values (Fig. 1). The 18O values of calcitic fossils generally vary from -0.1 to +1.1‰ VPDB for the studied interval, which corresponds to palaeotemperatures between +7.9 and +12.4°C (calculated with the equation of Anderson & Arthur 1983). The palaeotemperatures derived from the oxygen isotope composition of aragonitic ammonoid and nautiloid shells are distinctly higher (Fig. 1) with most of the estimates ranging from 15 to 23°C (calculated with the equation of Grossman & Ku 1986). The observed temperature difference may have resulted from different depth habitats of the organisms. The ammonites and nautiloids might have lived in surface waters and the temperature contrast might represent a palaeotemperature gradient between thermally stratified surface and deep waters of the Late Bajocian - Late Bathonian sea in the Polish Jura Chain. The ?13C values for the Upper Bajocian - Upper Bathonian belemnite rostra do not indicate major secular variations (Fig. 1). However, the data show a significant scatter of about 1.5‰. Several oyster shells show considerable higher 13C values (around +3‰ VPDB) compared to coeval belemnite rostra (between 0 and +1.5‰ VPDB). This may point to a metabolic fractionation effect that resulted in disequilibrium fractionation of carbon isotopes within belemnite skeletons (cf. Wierzbowski 2002). The aragonitic ammonite and nautiloid shells show a significant variation in 13C with values ranging from -3.7 to +2.2‰ VPDB. The carbon isotope composition of the oysters and the belemnites may suggest that the ?13C value of ancient seawater bicarbonate (HCO3-) averaged +3‰ VPDB.

6

Stratigraphic distribution of brachiopods in the Lower Jurassic – Middle Jurassic transition of the Lusitanian Basin (Portugal) and a proposal of biozonation

Andrade B., Joral F., Henriques M.

Volumina Jurassica

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2006

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Vol. 4, no. 1

143-143

EN

A detailed revision of the brachiopods of the Lower-Middle Jurassic transition in the Lusitanian Basin (Andrade 2006) has enabled the establishment of the stratigraphical distribution of this fauna. More than 2,000 specimens were collected at 11 sections throughout the basin, including the Bajocian GSSP in Murtinheira (Cabo Mondego). In all, 24 species, belonging to 14 genera, have been recognized along a stratigraphical interval that includes the Upper Toarcian, the Aalenian, and the Lower Bajocian. The Toarcian associations are characterized by species also recorded in neighbouring basins, such as Stroudithyris stephanoides, Sphaeroidothyris vari, Pseudogibbirhynchia bothenhamptonensis and Soaresirhynchia renzi; as well as species endemic to the Lusitanian Basin, such as Choffatirhynchia alcariensis, Nannirhynchia delgadoi, N. cotteri, Praemonticlarella conimbriguensis, Neozeilleria duartei and Pamirorhynchia(?) jorali. This mixed palaeobiogeographical character persists in the Aalenian, in which the associations include, together with widely distributed species such as Neozeilleria anglica, Pseudogibbirhynchia mutans or Lophrothyris withingtonensis, other species known in neighbouring basins, such as Sphaeroidothyris uretae and Neozeilleria sharpei, and other species recorded only in the basin, such as Soaresirhynchia minor, S. murtinheirensis and Sphaeroidothyris henriquesae. In the Lower Bajocian, excluding Loboidothyris perovalis, only endemic species are present (belonging mainly to endemic genera), such as Lusitanina bituminis, Stroudithyris choffati, Lusothyris atlantica and Mondegia limica. The interpretation of these distributions also enables to propose a brachiopod based biozonation for the studied interval. Three zones have been erected: 1. the Renzi Zone, for the Upper Toarcian, with two subzones: Renzi and Duartei; 2. the Anglica Zone, that ranges from the Aalensis Biochronozone of the Toarcian to the base of the Bajocian. It has been subdivided in 3 subzones: Nuskae, Anglica and Uretae; 3. the Choffati Zone, which comprises the main part of the Discites, Laeviuscula and Sauzei biochronozones, with two subzones: Bituminis and Limica; 4. this proposal of biozonation can be correlated with other established in neighbouring basins, such as the Iberian Range in Spain or the French Basins.

7

Storm deposits: evidence of event sedimentation in the Bajocian of the Central High Atlas, Morocco

Ait Addi A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

75-75

EN

During Bajocian time, the Central High Atlas of Morocco received several hundred meters of marls, shaly marls and carbonate deposits. These are spread out in two main domains: southern and northern platforms, situated N of Errachidia and S of Midelt cities, respectively, where shallow marine carbonates corresponding to the group of Bin El Ouidane formations dominate (Monbaron 1981); and central basin, presently forming the centre of High Atlas, where hemipelagic facies to shallow marine carbonates represent Agoudim (members II, III and IV) and Tazigzaout formations (Ait Addi 2000, Ait Addi 2002). The first evidence of event sedimentation in the Middle Jurassic of central High Atlas of Morocco has been provided by Ait Addi (2002). These deposits are Middle Jurassic (Bajocian) in age and are included in Agoudim and Tazigzaout formations in the central basin; and parts of Bin El Ouidane Group in the borders. The storm deposits are calcarenite beds of bioclastic packstone-grainstone character. These beds present symmetrical wave-ripples at their tops and show an internal structure with hummocky cross-stratification. The deposits are considered to be formed by tropical storms and hurricanes. The above characteristics are the effects of multiple reworking and winnowing of siliciclastic or bioclastic and/or carbonate material by oscillatory currents related to storm and to storm/tide currents interaction. Palaeobathymetric interpretation of related pelagic sediments indicates that the sedimentation occurred fairly deep, and that calcareous tempestites resulted from episodic resedimentation, mainly coincident with relative sea-level falls, in which major storm waves and tsunamis affected the sea bottom. This interpretation is in agreement with the regional palaeogeography and is further evidence of Jurassic storm-controlled sedimentation in adjacent Mediterranean basins.

8

Protoglobigerinids and Oberhauserellidae (Foraminifera) of the Bajocian-Bathonian from the Southern Jura Mts., France

Gorog A., Wernli R.

Volumina Jurassica

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2006

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Vol. 4, no. 1

233-233

EN

The Jurassic protoglobigerinids and other Globigerina-like foraminifera with aragonitic wall are generally considered as the ancestors of the Cretaceous planktonic foraminifera. They have been known for a long time as isolated specimens or in rock thin-sections, but they still raise several morphological and taxonomic problems. A detailed inventory of the Bajocian-Bathonian protoglobigerinids and other globigerina-like Foraminifera from the several localities of Southern Jura Mountains reveals a moderate abundance (>20%) of the Foraminifera fauna - and an unsuspected diversity, with 7 species of Conoglobigerinidae and 2 species of Oberhauserellidae. The discovery of two umbilical apertures in Oberhauserella as well as in some Conoglobigerina questions the generic taxonomy and makes the comparison with literature difficult. For these reasons, five new species have been proposed: Oberhauserella parocula and O.(?) aff. parocula (with 2 apertures), "Conoglobigerina" trilocula and "C". biapertura (with 2 apertures), C. solaperta and C. pupa. We demonstrate that Globuligerina balakhmatovae (Morozova 1961) (here emended) has a small globuligerine aperture as well as G. aff. dagestanica (Morozova 1961). Despite the different taxonomic concepts the Southern Jura Mountains associations, that are typical of the epicontinental platform, resemble the best those of the Dagestan and of the NW Caucasus (Morozova & Moskalenko 1961; Gorbachik 1986). They strongly differ from those of the oceanic Tethys, which are also very diverse (Gorog & Wernli 2002, 2003; Wernli & Gorog 1999, 2000).

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Evolution of Graphoceratidae and the Aalenian/Bajocian boundary at Bearreraig, Isle of Skye, NW Scotland

Morton N.

Volumina Jurassica

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2006

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Vol. 4, no. 1

196-196

EN

The GSSP for the base of the Bajocian Stage, and therefore the Aalenian/Bajocian boundary, has been defined at Cabo Mondego, western Portugal and ratified by IUGS. It was the first of the Jurassic Stages to be so defined. At the same time an Auxiliary Stratotype Point (ASP) at Bearreraig, Isle of Skye, NW Scotland was ratified by IUGS. The key marker event for the Aalenian/Bajocian boundary is evolution within the ammonite family Graphoceratidae. The original intention was to use as marker the first appearance of the genus Hyperlioceras (s.l. to include Toxolioceras and other mainly microconch “genera”) which evolved from the genus Graphoceras. However, in the light of detailed study of successions in various areas of western Europe and North Africa, this was modified. The earliest horizon of Hyperlioceras (H. incisum) proved to be too limited in distribution to be useful for correlation, so that the second Hyperlioceras horizon (H. mundum) was selected as the key marker for definition and correlation of the base of the Bajocian. The details of the evolution of Hyperlioceras from Graphoceras are best preserved and documented at Bearreraig, which is why this section was accepted as ASP. The succession is relatively thick (c. 24 m for the topmost Aalenian and lowermost Bajocian) and the ammonites are preserved mainly in a sequence of nodules. Each nodule contains an assemblage, dominated by juveniles, which approximates to a biological population. The dimorphic Graphoceras limitatum/carbatinum species remains virtually unchanged morphologically through some 15 m of strata (evolutionary equilibrium?) and overlap with the first two Hyperlioceras species. The main morphological change into the first Hyperlioceras species (dimorphic H. incisum/rotabilis) is in the shape of the venter (a punctuation event?). This is followed over 13 m of strata by gradational increases in size and involution through H. mundum/aspera and continuing into H. walkeri/contorta.

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Bajocian - Bathonian ammonite fauna of the Czorsztyn Unit, Pieniny Klippen Belt (Western Carpathians, Slovakia) : its biostratigraphical and palaeobiogeographical significance

Schlögl J., Rakús M., Mangold C., Elmi S.

Acta Geologica Polonica

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2005

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Vol. 55, no. 4

339-359

EN

The Parkinsoni Zone of the Late Bajocian and the Zigzag, Aurigerus and Retrocostatum Zones of the Bathonian have been identified on the basis of relatively highly diversified ammonite assemblages within seven ammonitico rosso sections belonging to the Czorstyn Unit, Pieniny Klippen Belt. The ammonite fauna has features in common with both the Mediterranean Province and the Sub-Mediterranean Province, containing abundant Phylloceratina and Lytoceratina on the one hand, but numerous Parkinsonia on the other. Ammonites of Arabian affinities belonging to the genus Micromphalites occur rarely in the Early Bathonian Zigzag Zone assemblage. Lytoceras joniaki, Lissoceras compressus and Cadomites (Polyplectites) minutus are proposed as new taxa.

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Pozycja stratygraficzna i paleogeograficzne znaczenie bajoskich wapieni krynoidowych w ewolucji pienińskiego basenu skałkowego

Krobicki M., Wierzbowski A.

Volumina Jurassica

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2004

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Vol. 2, no. 1

69-82

EN

The chronostratigraphical position of the crinoidal limestones in the Pieniny Klippen Belt (Carpathians, Poland) is well documented by ammonite faunas. It corresponds to the stratigraphical interval from the uppermost Propinquans and lowermost Humphriesianum zones of the Lower Bajocian to the Garantiana Zone of the Upper Bajocian. The hiatus recognized at the base of the crinoidal limestone complexes covers the time interval of the Laeviuscula Chron and a bulk of the Propinquans Chron of the Early Bajocian. The sedimentological features found in the basal beds of the crinoidal limestones include: presence of numerous phosphatic concretions, occurrence of pyrite framboids, as well as numerous rests of fauna (mostly ammonites and belemnites), all of them showing a slow sedimentation rate. The rapid change of sedimentation from dark shales of oxygen-depleted environment (Skrzypny Shale Fm. – Aalenian to earliest Bajocian) to overlying light crinoidal grainstones (Smolegowa Limeston Fm., Flaki Limestone Fm.) corresponded to an important geodynamic event that took place during Early Bajocian – the origin of the mid-oceanic Czorsztyn Ridge.

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Pedicellarie ze środkowojurajskich iłów rudonośnych i ich znaczenie w strategii życiowej jeżowców

Boczarowski A.

Volumina Jurassica

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2004

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Vol. 2, no. 1

141-150

EN

Numerous, well-preserved globiferous and ophiocephalous pedicellariae of echinoids have been found in samples from several brickyards of Central Poland: Gnaszyn and Kawodrza (Częstochowa), Blanowice (Zawiercie), Wrzosowa. This is the first study of the uppermost Bajocian and Bathonian pedicellariae from the Ore Bearing Częstochowa Clay Formation. Four new morphotypes are described. Effectiveness of the defensive echinoid strategy is discussed; the structures observed indicate the presence of poison in some but not all spines and pedicellariae of both living and fossil species. All main morphological types of pedicellariae are compared. Morphotype I of globiferous pedicellariae and morphotype III of ophiocephalous pedicellariae are similar to those from the recent family Parechinidae. Jurassic echinoid Pelanechinus has ophiocephalous pedicellariae reminding morphotype II, as described from the Polish Bathonian.

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First record of Jurassic (Toarcian - Bajocian) ammonites from the northern Lut Block, east-central Iran

Seyed-Emami K., Fürsich F. T., Wilmsen M., Schairer G., Majidifard M. R.

Acta Geologica Polonica

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2004

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Vol. 54, no. 1

77--94

EN

A very thick and lithologically rather unusual marine sedimentary succession is described from the Kuh-e-Shisui area, northwestern Lut Block (east-central Iran). It contains a low diversity ammonite fauna comprising the families Dactylioceratidae, Hildoceratidae, Graphoceratidae, Hammatoceratidae, and Sonniniidae, which are concetrated in several levels, indicating the Lower-Lower Middle Toarcian, Upper Toarcian, Aalenian, and Lower Bajocian. The ammonite fauna, consisting of 21 taxa, descibed for the first time from the Lut Block, corresponds to that of the Badamu Formation of the Kerman-Ravar region (southern Tabas Block, to the west of the Lut Block), but is far less diverse. An exception is the occurrence of Lower Toarcian Harpoceratinae and Hildoceratinae, which hitherto have not been recorded from east-central Iran. The ammonite fauna is closely related to that of northwestern Europe.

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Charakterystyka palinofacjalna najwyższego bajosu i batonu okolic Włocławka

Barski M.

Volumina Jurassica

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2003

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Vol. 1, no. 1

7-12

15

Biostratygrafia amonitowa formacji częstochowskich iłów rudonośnych (najwyższy bajos - górny baton) z odsłonięć w Częstochowie

Matyja B., Wierzbowski A.

Volumina Jurassica

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2003

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Vol. 1, no. 1

3-6

16

Ammonites and stratigraphy of the uppermost Bajocian and Lower Bathonian between Częstochowa and Wieluń, Central Poland

Matyja B., Wierzbowski A.

Acta Geologica Polonica

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2000

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Vol. 50, no. 2

191-209

EN

A detailed biostratigraphical study of the black clays and siltstones with ironstone nodules of the Ore Bearing Częstochowa Clay Formation in the brick-pits at Częstochowa and Wieluń resulted in recognition of the following standard ammonite zones and subzones: the Parkinsoni and Bomfordi subzones of the Parkinsoni Zone of the uppermost Bajocian; the Convergens, Macrescens and Yeovilensis subzones of the Zigzag Zone, and the Tenuiplicatus Zone of the Lower Bathonian. The ammonite faunas are of Submediterranean character, although markedly impoverished when compared with those of the most classic areas of the province. This impoverishment is especially well seen in the uppermost Bajocian - lowermost Bathonian part of the succession, where the only numerous ammonites are these of the genus Parkinsonia, together with rare representatives of Cadomites; and in theuppermost part of the Lower Bathonian, where representatives of the corresponding macro- and microconchs- Asphinctites tenuiplicatus (BRAUNS), and Polysphinctites secundus (WETZEL) - predominate. In the palaeontological part of the paper 14 species belonging to the genera Oxycerites, Parkinsonia, Cadomites, Wagnericeras, Asphinctites and Polysphinctites are descibed. Of these, particular attention is paid to a form referred to as Parkinsonia (Parkinsonia) aff. dorni ARKELL from the uppermost Bajocian, represented by several specimens of various growth stages, which may be tentatively compared with the poorly diagnostic small, incomplete type-specimens of P. dorni.