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The investigated outcrop in Płucki. A, location map in the Holy Cross Mountains (HCM), Central Poland (modified from Kowalczewski 1971). B, general picture of the outcrop; the place of the fossil-bearing horizon is marked with an arrow. C, diagrammatic cross section through the Holy Cross Mountains from the Givetian to the top of the Upper Devonian (modified after Szulczewski 1995) with the probable position of the investigated localities (a, marly limestones and shales; b, condensed cephalopod and crinoidal limestones; c, marly limestones; d, calcirudites; e, bedded limestones; f, dolomites; g, massive and bedded limestone; h, cephalopod limestones; i, clayey and marly shales).
Source publication
The arthrodire placoderm, Dunkleosteus sp., is reported from the Upper Devonian (Frasnian) of the Holy Cross Mountains, Poland. The material comprises partially preserved remains of two individuals found in the Kellwasser-like horizon of the P³ucki locality. The remains are preserved as broken bone fragments redeposited from shallower environment i...
Contexts in source publication
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... source locality of the reported material is located in the Płucki village near the town of Łagów in the central part of the Holy Cross Mountains (central Poland, Fig. 1). This locality represents important strata of the Kowalczewski 1971). B, general picture of the outcrop; the place of the fossil-bearing horizon is marked with an arrow. C, diagrammatic cross section through the Holy Cross Mountains from the Givetian to the top of the Upper Devonian (modified after Szulczewski 1995) with the probable ...
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... ( Fig. 2A-C). The suborbital plate comprises the suborbital lamina preserved only in its anteriormost part and the blade which seems to be preserved completely but is strongly eroded. The blade is about 18 cm long and its maximum width reaches 4 cm. The lamina for the posterior supragnathal is well visible, especially on the cross section (Fig. 3D, D1). Anterior dorsolateral plates have no natural margins and the only feature well recognizable is a broken glenoid condyle. Specimen MWG UW ZI/43/0053 (Fig. 4A, B) re- presents a mostly preserved nuchal plate with very partially preserved paranuchal and right central plates. Both the visceral and outer surfaces are well visible. This ...
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... central plate associated with part of the pineal plate. The anterior margin shows elongated contact faces for the posterior margin of the preorbital plate. This margin is transverse and gently curved backwards. On the visceral side the deep depression of the pineal pit is bordered posteriorly and laterally by a ridge which is opened anteriorly (Fig. 4C1). No natural margins could be recognized due to the high degree of abrasion of both surfaces of the ...
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... nuchal plate in both cases described above has a rectangular anterior margin with a V-shaped incision between centrals (see Muz. PGI-NRI 1809.II.18; Fig. 2C1, 6B) and moreover a deep overlap area for the central and paranuchal plates. These are characteristic features of Dunkleosteus (compare Heintz 1931, 1932 fig. 12; pl. 1) which brings the Polish specimens closer to Dunkleosteus marsaisi ( Lehman 1956, pl. 6;or Moroccan D. terreli if is synonymized with D. marsaisi (Lehman, 1954) from ...
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... nuchal plate in both cases described above has a rectangular anterior margin with a V-shaped incision between centrals (see Muz. PGI-NRI 1809.II.18; Fig. 2C1, 6B) and moreover a deep overlap area for the central and paranuchal plates. These are characteristic features of Dunkleosteus (compare Heintz 1931, 1932 fig. 12; pl. 1) which brings the Polish specimens closer to Dunkleosteus marsaisi ( Lehman 1956, pl. 6;or Moroccan D. terreli if is synonymized with D. marsaisi (Lehman, 1954) from Morocco (Rücklin 2002)) and Dunkleosteus sp. illustrated by Ivanov & Ginter (1997, fig. 4B). The nuchal plate outline fits well with Dunkleosteus marsaisi (Lehman ...
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... Dunkleosteus marsaisi ( Lehman 1956, pl. 6;or Moroccan D. terreli if is synonymized with D. marsaisi (Lehman, 1954) from Morocco (Rücklin 2002)) and Dunkleosteus sp. illustrated by Ivanov & Ginter (1997, fig. 4B). The nuchal plate outline fits well with Dunkleosteus marsaisi (Lehman 1956, fig. 8) and D. intermedius (terreli) (Heintz 1932, text- fig. 12) but is narrower. It resembles the nuchal plate of D. amblyodoratus Carr & Hlavin, 2010 ( fig. 6A-C) also in size, however, Polish specimens have a more prominent anterior part. Also, the occipital thickening is roughly typically developed and resembles many specimens referred to Dunkleosteus. Both the described nuchal plates are ...
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... the ridge are small posteriorly or almost absent) is unusual for Dunkleosteus (e.g. Carr & Hlavin 2010, fig. 6A, B) and occurs not very often. A similar case was illustrated by Lehman (1956, pl. 16F), who identified his fragmentary specimen as Dinichthyidae sensu lato. The shape and morphology of levator pits on specimen Muz. PGI-NRI 1809.II.18 (Fig. 2A1), which are more rounded than ellipsoidal and are bounded posteriorly by a very thin transverse ridge, are similar to features present also in the specimen illustrated by Lehman (1956, pl. 16F). A comparable feature occurs in some undescribed specimens stored in the Famennian part of the collection, in the Cleveland Natural History ...
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... median dorsal plate resembles the Dunkleosteus pattern in its outline (e.g. Dean 1908, fig. 61) but is different from most of the dunkleosteid median dorsal plates (see Heintz 1932, text-fig. 44;Lehman 1956, pl. 14). However, anterolateral margins are not recognized; they must have had deep embayment in the anterior part comparable to that of D. marsaisi (Lehman 1956, pl. 14B). The development of the keel on the specimen ...
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... in the anterior part comparable to that of D. marsaisi (Lehman 1956, pl. 14B). The development of the keel on the specimen analysed is quite typical for the genus. It is present along almost the entire plate and gradually becomes crude at the posterior margin with the carinal process, resembling the specimens of Dunkleosteus illustrated by Heintz (1932, text-fig. 44). The comparison with other material from the Holy Cross Mountains indicates different affinities. The specimens of Dunkleosteus denisoni described by Kulczycki (1957: 313, text- fig. 10, pl. VI, fig. 4, fig. VII) represent a much smaller taxon which possesses a huge keel and carinal process. Though, even if the keel and process are ...
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... plate and gradually becomes crude at the posterior margin with the carinal process, resembling the specimens of Dunkleosteus illustrated by Heintz (1932, text-fig. 44). The comparison with other material from the Holy Cross Mountains indicates different affinities. The specimens of Dunkleosteus denisoni described by Kulczycki (1957: 313, text- fig. 10, pl. VI, fig. 4, fig. VII) represent a much smaller taxon which possesses a huge keel and carinal process. Though, even if the keel and process are broken, it is clear that these were not very prominent in the specimen described herein (comp. Kulczycki 1957, pl. VII and Fig. 5). Moreover, specimens described by Kulczycki (1957) are middle Famennian in ...
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... the transverse occipital thickening, cucullaris depression, the morpho- logy of the internal side of the pineal opening and the position of the external and internal opening for the endolymphatic duct fit to the general morphology of the genus Dunkleosteus illustrated by Leriche (1931), Heintz (1932, text-figs 12, 13, pls 1, 2) and Stensiö (1963, fig. 112A, ...
Citations
... Dunkleosteus currently exists as a wastebasket taxon containing a large number of species established upon various isolated, non-overlapping skeletal elements, and many are insufficiently characterized or probably synonymous with other taxa. This is also not considering additional Dunkleosteus material from California [70], Texas [71] and Poland [72] which has been only referred to as Dunkleosteus sp. ...
A new species of Dunkleosteus, D. tuderensis sp. nov., is named based on an infragnathal from the Famennian of the Tver Region, Russia. CT scanning of the holotype revealed two high-density bony constituents comparable in position and interrelations to components described for coccosteomorph arthrodires, supported by the presence of at least two clusters of large vascular canals marking separate arterial supplies. Coccosteomorph and dunkleosteid pachyosteomorphs exhibit similar growth patterns including labio-basal depositions of vascularized bone in the infragnathals and basally in the supragnathals. In contrast to coccosteomorphs, dunkleosteid reinforcement of the occlusal margins occurred via the formation of dense osteonal bone, in parallel with resorption forming extensive lingual fossae. Active bone remodeling proceeded without a complete reworking of the primary osteonal bone structure and the original arrangement of vascular canals. Due to inconsistent anatomical terminology in gnathal elements of dunkleosteid arthrodires, a revised terminology is suggested and new terms are introduced.
... It is difficult to ascertain if the smaller size is merely a regional characteristic or due to the younger ontogenetic stage of the described specimen. It is also noteworthy that the Gorgonichthys from Kowala described herein and the Dunkleosteus from Płucki (Szrek and Wilk, 2018) are the only large marine predators ever found in the Devonian of the Holy Cross Mountains. They appeared during the Late Devonian, correlated with the general submersion of the entire area and the change in placoderm assemblages, with the Early and Middle Devonian demersal assemblages replaced by Late Devonian diversified nektonic-dominated communities (Szrek, 2020). ...
... Numerous vertebrate remains are represented mainly by arthrodire placoderms and show various states of preservation, reflecting their history before subsequent burial (Szrek and Wilk 2018). Most of the fragments are disarticulated and show marks of abrasion (Fig. 7a). ...
Of all the Devonian stratigraphic boundaries, the Frasnian–Famennian transition (372.2 ± 1.6 Ma) preserves the record of one of the most significant crises in the history of life, the final stages of which lie buried in the distinctive Kellwasser limestone. The Kellwasser facies occur in Western and Central Europe and the commonly cited Płucki area of Poland’s geologically rich Holy Cross Mountains is the only site in that region where the Frasnian–Famennian boundary is considered to occur within Kellwasser facies. At this locality, the limestone contains slump structures, comprising contorted beds and folds. Actually the Kellwasser-like limestone from Płucki is composed of a mixture of three distinct types of sediment, occurring as clasts, commonly deformed and sheared, and matrix, rather than being one homogenous bed, as previously considered. Thus, earlier studies and interpretations of this limestone may need revising. This paper documents the evidence for sediment erosion and reworking, debris flows, sliding and soft-sediment deformation on a submarine slope, and suggests that seismic events were the likely triggering mechanism for slumping and resedimentation.
... Regarding many world-wide famous dis- coveries based of fossil record of Łagów, e.g. sex- ual dimorphism of ammonoids (Makowski 1963), record of the 2nd biggest extinction event in the history of life ( Racki et al. 2002), well-preserved big placoderm fish assemblage (Szrek, Wilk 2018), the name of Łagów and its vicinities is becoming to be recognisable among non-geologists tourists. Actually, the marine Devonian strata (419-365 Ma), the most abundant on the described area, are so folded and faulted that the exact nature of the rock succession has not yet been wholly de- termined, and still may bring new discoveries as a 'scientifically open' area. ...
