Piotr Szrek

We report here the first anomoepodid track from the Upper Cretaceous of Europe referred to the ichnogenus Neoanomoepus. The track was found very recently in the upper Campanian strata of Roztocze Hills, in southeastern Poland. This region was located on the northeastern margin of Kukernitz Island, which was a part of the Late Cretaceous European archipelago. Anomoepodid morphology of the newly found track together with its stratigraphic and palaeogeographic location speak in favour of its rhabdodontid affinity. We also discuss here associated tetrapod ichnotaxa from the late Campanian of Roztocze Hills. Discussed and partly reviewed tetrapod ichnoassemblage of Roztocze includes such ichnogenera like cf. Wakinyantanka isp., Hadrosauropodus, Dromaeosauripus isp., cf. Saurexallopus isp. and cf. Haenamichnus isp.

Herein we present the Famennian coelacanth remains from the Holy Cross Mountains (Poland). Despite of poor preservation of the studied specimens, we recognized and described two species, Diplocercides heiligenstockiensis (Jessen 1966) and Diplocercides kayseri (von Koenen 1895) based on entopterygoid, cleithra, gular plates, lachrymo-jugals, and other cranial plates. Their disintegrated and poorly preserved remains display the complex taphonomical history of the fish corpses. They were transported long-distance into deep water areas, where they were covered by sediment and seemingly moved by non-directional bottom currents, resulting in carcass decomposition.

We report the first occurrence of trace fossils in placoderm bones from the Upper Devonian of the Holy Cross Mountains. A taxonomic analysis of three ichnogenera revealed the earliest evidence of Sulculites (ie., Sulculites bellus), characterised by curved grooves known from the tortoise shells, the potential Osteocallis? isp. consists of irregular and shallow grooves, which were first described on dinosaur bones from continental deposits, while Karethraichnus? isp. being a deep and cylindrical boring, recognized for the first time in turtle shells. They show the evidence of post mortem erosional activity by organisms (e.g., worms) that penetrated the decaying carcasses to search for nutritional particles, graze microbial mats and colonize the osteic substrate. The massive dermal bones of placoderms seem to be appealing to scavengers, albeit rather as an opportunistic behaviour. Nevertheless, this uncommon finding may be caused by the relatively limited attention that has been paid to this phenomenon. The described traces also represent the oldest evidence of macrobioerosion in osteic substrate, as well as the oldest documented occurrence of these forms that have been known so far.

A new trackway produced by crawling fishes, which includes imprints of the trunk, snout, tail, body drag traces, and pectoral fins, was discovered in the Lower Devonian (middle–upper Emsian) marginal marine deposits in the Holy Cross Mountains, Poland. The snout imprints are represented by a low-angle variant of the already described Osculichnus tarnowskae, which has generally been interpreted as a hunting trace of fishes. However, in this case, it is considered an imprint of a fish’s snout, used for anchoring in the sediment during the locomotion of at least partially emerged fish. This compound trackway provides the first evidence of the previously unknown life behaviour and locomotion abilities of dipnoan fishes in the early stage of their evolution and documents a testing land mobility skills of vertebrates, predating by about 10 million years fully terrestrial tetrapods locomotion traces. Similar trackways are produced by extant lungfish during terrestrial locomotion. The trackway co-occurs with a new resting trace produced by a dipnoan fish supporting itself with one or two pairs of fins on the bottom.

New studies on Frasnian ptyctodonts, including the revision of historic material in addition to the description of new material, have resulted in the detailed description of two species of Ptyctodus (Ptyctodus obliquus, Ptyctodus kielcensis), eight indeterminate specimens of Ptyctodus sp. from the Holy Cross Mountains and two specimens from Dębnik near Kraków, four indeterminate specimens of Rhynchodus sp., and two specimens of Ptyctodontidae gen. et sp. indet. from the Holy Cross Mountains. One of the described species (P. kielcensis) appears to be endemic for the Holy Cross Mountains region. Based on general knowledge of the Frasnian stratigraphy of the Holy Cross Mountains and on the conodont material obtained from the fragments of the sediments attached to specimens, it was possible to define the predetermined subdivision of the Frasnian as ranges of conodonts and the fauna to be placed within conodont zones. Previously only antiarchs, bottom-feeding placoderms, had been recovered from the Lower and Upper Kellwasser horizons from this area (Płucki); thus, the occurrence of ptyctodonts represents an additional placoderm taxon. This work describes the first placoderm remains from Dębnik near Kraków, which also represent the first described placoderms from an area other than the Holy Cross Mountains.

Among the hundreds of collected Devonian vertebrate macrofossils in the Holy Cross Mountains, placoderms dominate and provide data on their morphology, distribution and taphonomy. So far 17 out of more than 500 studied specimens have revealed bones with surfaces covered by sediment-filled trace fossils. The traces have been made on the vertebrate remains before their final burial. The borings, oval in cross-section, include dendroidal networks of shallow tunnels or short, straight or curved individual scratches and grooves, which frequently create groups on the both sides of the bones. ? Karethraichnus isp. from Kowala and ? Osteocallis isp. from Wietrznia are the oldest record of these ichnogenera. Sedimentological clues indicate a shallow water environment, probably from the slope below the storm wave base.

The internal skeleton of “conventionally defined” Chondrichthyes (i.e., chondrichthyans excluding acanthodians; Zhu et al., 2013) is built up of calcified cartilage, which is characterized by a ver...

The remains of Late Devonian placoderms from the Holy Cross Mountains area have already been established and widely recognized thanks to the diligent studies of Gorizdro-Kulczycka (1934) and Kulczy...

Dipnoan remains are mainly known from the Middle and Upper Devonian deposits in the Holy Cross Mountains, Poland. The presence of this group in the Lower Devonian was suggested by feeding trace fossils apparently made by dipnoan fish. Recent studies confirm the occurrence of body fossils based on single skeleton elements. Fragments of heavily ossified mandible and skull-roof represent dipnoan remains appear to belong to a primitive ‘Dipnorhynchus’-like form. It supplements the knowledge on the Early Devonian ecosystem at the Holy Cross Mountains and dipnoan ichnological record is now supported by fossil remains of a putative trace-maker for Osculichnus isp.

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.