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Exceptional soft-tissue preservation in boring ctenostome bryozoans and associated “fungal” borings from the Early Devonian of Podolia, Ukraine

100%

Olempska E.

Acta Palaeontologica Polonica

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2012

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tom 57

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nr 4

Colonies of boring ctenostome bryozoans and microborings of “fungi” that occur in the Early Devonian (Lochkovian, ~416 Ma) of Podolia, western Ukraine, have soft−tissue preserved by phosphatization. These comprise exceptional three−dimensional body walls of feeding zooids with probable parietal muscles inserted on the cystid wall, and setigerous collars twisted within the vestibulum. The presence of collars in this Early Devonian ctenostomes proves the existence of this feature for more than 416 Ma of ctenostome evolution. Phosphatized remains of the zooid walls are interpreted as relicts of the originally chitinous cystid walls. This is the first record of soft−tissue fossilization in a boring bryozoan. The presence of cavities (specialized heterozooids), empty or filled with laminated calcium phosphate, is also documented in bryozoans for the first time. These cavities are interpreted as “store−rooms” in which the bryozoans accumulated nutrients. The new taxon, Podoliapora doroshevi gen. et sp. nov. is described. In additional, phosphatised fungi−like endoliths co−occur with bryozoans.

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Colour patterns in Early Devonian cephalopods from the Barrandian Area: Taphonomy and taxonomy

100%

Turek V.

Acta Palaeontologica Polonica

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2009

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tom 54

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nr 3

491-502

Five cephalopod specimens from the Lower Devonian of Bohemia (Czech Republic) preserve colour patterns. They include two taxonomically undeterminable orthoceratoids and three oncocerid nautiloids assigned to the genus Ptenoceras. The two fragments of orthocone cephalopods from the lowest Devonian strata (Lochkovian, Monograptus uniformis Zone) display colour patterns unusual in orthoceratoids. They have irregular undulating and zigzag strips that are preserved on counterparts of adapertural regions of specimens flattened in shale, despite their original aragonitic shell having been completely dissolved. These are probably the result of the proteinous pigment inside the shell wall, being substituted during diagenesis by secondary minerals leaving only an altered trace of the original shell. Orthoceratoids from sediments unsuitable for preservation of this feature discussed here thus demonstrate an exceptional case of preservation of colour patterns, not only within Devonian cephalopods but also within other Devonian molluscs. Three specimens of Ptenoceras that preserve colour patterns come from younger Lower Devonian strata. Oblique spiral adaperturally bifurcating bands are preserved in P. alatum from the Pragian and zigzags in P. nudum from the Dalejan. Juvenile specimen of Ptenoceras? sp. from the Pragian exhibits highly undulating transversal bands—a pattern resembling colour markings in some Silurian oncocerids. Dark grey wavy lines observed on the superficially abraded adapical part of a phragmocone of nautiloid Pseudorutoceras bolli and interpreted formerly to be colour markings are here reinterpreted as secondary pigmented growth lines. Other Devonian fossils including a single brachiopod and several gastropods from the Barrandian Area with preserved colour patterns are mentioned. Variety of cephalopod colour patterns, their taxonomic significance, function and significance for palaeoecological interpretation, palaeoenvironmental conditions favouring colour pattern preservation and systematic affiliation of taxa with colour pattern preserved are discussed.

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Sublethal injuries in Early Devonian cephalopod shells from Morocco

100%

Klug C.

Acta Palaeontologica Polonica

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2007

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tom 52

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nr 4

Internal moulds of the relatively small− to moderate−size shells of Early Devonian ectocochleate cephalopods (typically <150 mm diameter) occasionally display traces of repaired shell damage. Presumably, these animals with their highly specialized buoyancy device, the phragmocone, lived in the water column. It is uncertain as to how the shells of these animals were damaged; one likely cause would be predatory attacks but the identity of the perpetrator remains uncertain. So far, no remains of arthropods capable of breaking or cutting shells have been found in the fossiliferous outcrops of this age in the Anti−Atlas (Morocco). The only macrovertebrate remains of this age are of acanthodian and placoderm fish which probably lived a more or less benthonic life style. Additionally, a fish attack on these cephalopods would probably have destroyed most of the thin−shelled conch and killed the animal. Most of the repaired shell breaks are triangular in shape which is characteristic for cephalopod bite marks. Additionally, the paired arrangement of the fractures in over 70 bactritoids supports the hypothesis that it was a cephalopod attacking another cephalopod. It cannot be excluded with certainty that occasional vertebrate attacks left traces on their shells. Fossil evidence indicates that the development of tightly coiled conchs was a rapid evolutionary event in the Ammonoidea in the Early Devonian; however, the evolution of coiling is probably not directly related to predation pressures because the ratio of injured to healthy specimens is roughly the same in Zlíchovian bactritoids with orthoconic and ammonoids with coiled shells.

4

Soft-tissue attachments in orthocerid and bactritid cephalopods from the Early and Middle Devonian of Germany and Morocco

100%

Kroger B., Klug C., Mapes R.

Acta Palaeontologica Polonica

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2005

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tom 50

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nr 2

In the Early to Middle Devonian shale sequences of Germany and Morocco, pyritised and secondarily limonitised cephalopod remains are common. Details of the soft−tissue attachment structures are sometimes preserved on the internal moulds of the body chamber and phragmocone of these cephalopods. Some of the studied Orthocerida show a very faint annular elevation and a dorsal furrow. A few Bactritida show a distinctive annular elevation with two circular bands. The bands form a paired or threefold lobe at the dorsum of the shell. Morphological differences between Orthocerida and Bactritida suggest different soft part morphologies. A comparison of the attachment scars shows that the Bactritida are intermediate between the Orthocerida and ammonoids with regard to their muscle attachment scars. The shape of the muscle scars are interpreted as indication for a planktonic lifestyle in Orthocerida and a comparatively active, nektonic lifestyle in Bactritida and ammonoids. The new genus Acanthomichelinoceras is erected. Acanthomichelinoceras commutatum, Cycloceras sp., Bactrites gracile, Bactrites sp. A, Bactrites sp. B, and Bactrites sp. C are described.

Ograniczanie wyników

4 Acta Palaeontologica Polonica

2 Klug C.

1 Kroger B.

1 Mapes R.

1 Olempska E.

1 Turek V.

1 2012

1 2009

1 2007

1 2005

Exceptional soft-tissue preservation in boring ctenostome bryozoans and associated “fungal” borings from the Early Devonian of Podolia, Ukraine

Colour patterns in Early Devonian cephalopods from the Barrandian Area: Taphonomy and taxonomy

Sublethal injuries in Early Devonian cephalopod shells from Morocco

Soft-tissue attachments in orthocerid and bactritid cephalopods from the Early and Middle Devonian of Germany and Morocco