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The Devonian period is known as "The Age of Fish", but could also be known as "The Age of Brachiopods." In the Early / Lower Devonian, brachiopods reached the height of their diversity towards its end in the Emsian. We see the ancestral groups occurring, lingulids, craniids, orthids, protorthids, pentamerids, rhynchonellids and strophomenids, as well as the later successful groups we have seen before such as atrypids, athyrids and orthotetids, plus the rise of spiriferids, spiriferinids and productids and the beginning of the terebratulids. By the end of the Devonian , several of these groups are extinct or severely reduced in importance and brachiopods never quite recover. Also, the Devonian is the last time we see trilobites with such variation, large sizes and numbers and orthocerids too are much more uncommon after the rise of the goniatites. The massive tabulate coral reefs also disappear after the Devonian. Fascinating period and I hope to share some of its wonders with you. Equally, a lot of this is rather new to me, so I would be very grateful for any assistance, corrections or further information on my specimens. Thank you. The Early Devonian epoch is split into three stages, so let's start with the first of those, the Lochkovian, that began about 419 mya and finished roughly 411 mya. I have been sent a nice selection of brachiopods from the Kalkberg Formation, Helderberg Group by the Mighty @Misha, mostly. But the kind gentleperson also sent me this fascinating little bryozoan hash : It is dominated by fenestellids, which is usually the case in the Devonian, but other orders sill occur. These ones, I think, are Fenestella, but there are so many species in the formation that I wont take a guess as to species : Not sure what this one is ;
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- aguion formation
- area de bonar
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Probably Gosslingia breconensis Heard 1927. Taxonomy from Fossilworks.org. Edwards 1970, p. 226: “In his preliminary report in 1925, Heard had called the plant Psilophyton, but he renamed it Gosslingia when he presented an account of its anatomy and morphology in 1927.” Emended diagnosis for the genus (Edwards 1970, p. 237): "Plant rootless and leafless. Gregarious erect axes cylindrical, dichotomously and pseudomonopodially branched, arising from dichotomously branched rhizomes with rhizoids. Stems circinately coiled in apical regions: surfaces of some axes with protuberances; large projections (axillary tubercles) occur below branching points. Axes have elliptical xylem strands composed of tracheids with scalariform and reticulate pitting; protoxylem exarch, xylem surrounded by phloem; axillary tubercles with vascular strands circular in cross-section. Outer cortex composed of many layers of thick-walled elongate cells. Epidermis with stomata. Stalked sporangia borne laterally at intervals over a definite fertile region. Sporangial shape variable ranging from reniform to globose, with heavily carbonized convex margin. Spores variable in shape, with part of exine smooth and part ornamented by spini, coni and bacculae.” Reconstruction from Edwards 1970, p. 231: References: Heard, A. (1925) Psilophyton breconensis. Rep. Brit. . (Southampton), pp. 311-312. Heard, A. (1927) On Old Red Sandstone plants showing structure from Brecon (South Wales). Quart. J. geol. Soc. Lond. 85, 195-209. Edwards, D. (1970) Further observations on the Lower Devonian plant, Gosslingia breconensis Heard. Phil. Trans. R. Soc. Lond. B258225–243 http://doi.org/10.1098/rstb.1970.0034. Kenrick, P. & Edwards, D. (1988). The anatomy of Lower Devonian Gosslingia breconensis Heard based on pyritized axes, with some comments on the permineralization process. , 97(2), 95–123. doi:10.1111/j.1095-8339.1988.tb02456.x
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- devonian
- gosslingia
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L.S., Hope someone on TFF can help me with the identification of a plant fragment from the Lower Devonian (Pragian) of the Belgian Ardennes. The specimen in question consists of a 17 mm-long, 12 mm-wide oval-shaped body, which is seemingly covered in equant scales (though this could also be an artefact of the surface preservation) and has curved spine-like protrusions (see right hand-side of specimen in first two photographs). The detailed structure of the specimen is quite difficult to capture, so I added four photographs taken under different lighting conditions. Hope this is enough to showcase the main features. To my eye, the overall texture and "spines" do resemble those of Drepanophycus-like stems, which have been observed at the locality. However, I find it difficult to explain the oval-shape of this structure in terms of a stem fragment. This rounded shape gives it an almost strobilar appearance. The specimen is associated with long, naked axes having a smooth surface, present in the same slab of rock, but not in organic connection. Other floral elements encountered at the locality mainly include zosterophyllopsids. Are you aware of any scaled strobilar structures from the worldwide Lower Devonian to which I could compare my Belgian find? Or do you think this specimen should be interpreted as a (rounded) stem fragment? I'm really struggling with this one, so I would love to hear your thoughts! Kind regards, Tim
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Taxonomy according to Carlsson et Blom, 2008. Voichyshyn, 2011 p. 157:” Diagnosis (based on data of Carlsson and Blom 2008). — Medium sized scolenaspidians (L is about 65 mm). The width of the shield considerably exceeds its length (L/S about 0.5). The prepineal part of the shield is somewhat shorter than the postpineal one (B/C 0.8). Anterior margin of the shield somewhat narrows and has poorly expressed obtuse rostral corner. The cornual processes are very long, narrow, and bent caudally. The abdominal division of the shield is narrow and probably narrows backwards. The hypophyseal division of the nasohypophyseal opening is larger than the nasal one. Orbits are small (S/Os about 32) and oval. The pineal plate is well developed. The dorsal field is moderately narrow and, probably, relatively short (Ld/Sd is about 2.25). Lateral fields are rather narrow, reaching back not farther than to the proximal part of the cornual processes. The ornamentation of the dermal skeleton consists of tesserae covered by minute tubercles.” Line drawing from Carlsson & Blom 2008, p. 320: Identified by oilshale using Carlsson et Blom, 2008. References: Carlsson, A., Blom, H. (2008) A new scolenaspidid (Osteostraci, Vertebrata) from the Lower Devonian of Podolia, Ukraine. Paläont. Z. 82, 314–323. https://doi.org/10.1007/BF02988898 VOICHYSHYN, Victor (2011) THE EARLY DEVONIAN ARMOURED AGNATHANS OF PODOLIA, UKRAINE. PALAEONTOLOGIA POLONICA. No. 66, p. 1-211. https://doi.org/10.4202/pp.2011.66_001 Voichyshyn V.K. (2015) Devonian Fish Fauna. – Lviv, 310 p. (Scientific collections of the State Natural History Museum; Issue 5)
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- devonian
- dniester formation
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Rhinopteraspis dunensis Roemer, 1855 - a pteraspidid heterostracan agnathan
oilshale posted a gallery image in Member Collections
From the album: Vertebrates
Rhinopteraspis dunensis Roemer, 1855 Early Devonian Upper Pragian Odenspiel North Rhine-Westphalia Germany Length 10cm / 4" -
These seem to be traces, but have an odd assortment of characteristics. Found in lake shore glacial float. Most likely Tarratine sandstone,a Pragian marine delta related formation. Any thoughts ?
