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ElToro

Coronocephalus?

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ElToro

This Coronocephalus trilobite just arrived in the mail. I don't really know a lot about them. I believe it is most likely C. gaoluoensis. I do know its from Hunan, China, but not much else. Middle Silurian?

Anyone got any info? Also, what do you guys think of the fossil? I quite like it even though it needs to be cleaned up a little.

Thanx! B)

post-20038-0-29830300-1462776285_thumb.jpg

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FossilDAWG

If you search the forums for "Coronocephalus" you'll find several threads with lots of information. Forum member Piranha, our resident trilobite authority par excellance, has commented on them a few times.

Don

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ElToro

If you search the forums for "Coronocephalus" you'll find several threads with lots of information. Forum member Piranha, our resident trilobite authority par excellance, has commented on them a few times.

Don

Thanx mate. Yea, I've since done some research on them and searched the forum. Quite a cool fossil but I need to take a toothbrush to it cause it still has a lot of mud on it. And eventually I'll get an air scribe to remove that matrix from its cephalon (head)...B)

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FossilDAWG

Be very gentle and very cautious. The specimen I have, and the ones I have seen, are in soft shale and could easily be damaged by vigorous scrubbing with a wet toothbrush.

Don

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abyssunder

ACTA PALAEONTOLOGICA SINICA Vol.18, No.2, March,1979 and part of SILURIAN ENCRINUROIDES (TRILOBITA) FROM SOUTHWESTERN CHINA - Wu Hong-ji (Nanjing Institute of Geology and Palaeontology, Academia Sinica) are in this document : Document.pdf

" Although the genus Coronocephalus Grabau 1924 is frequently found in the Silurian rocks in Southwest China and the description of this genus was completed in 1938, discussion on the genus actually began in later years. A subfamily Coronocephalinae was raised by Chang in 1983, including four genera, namely Coronocephalus, Senticucullus, Kailia, Rongxiella. In the present paper, 34 coronocephalid species are compared with rex, indicating that they can be divided into two groups. The type species of three genera (or subgenera), Coronocephalus rex, Coronocephalus (Coronocephalina) gaoluoensis and Senticucullus elegans, are included in the same group. For this reason, the present paper holds that Senticucullus, Coronocephalus (Coronocephalina) and Coronocephalus are synonymous, and therefore Senticucullus and Coronocephalina should be abandoned. Herein is established a new subgenus Coronocephalus (Coronaspis), which appeared in the late Xiushan age, and extended into the Huixingshao or corresponding stratigraphic units. " On genus Coronocephalus Grabau, 1924 Silurian trilobite - Wu Hong ji, 1990; Gushengwu Xuebao = Acta Palaeontologica Sinica 29(5): 527-547

" Amongst new specimens collected from the upper part of the Telychian Xiushan Formation of Llandovery (Lower Silurian),at Wanmin town in Yongshun County, western Hunan, nearly all are assigned to Coronocephalus gaoluoensis Wu. More than twenty are whole and articulated specimens, thus providing a sound basis for the study presented here. The cephalon of this trilobite is very peculiar. Its anterior sections of the facial sutures traverse across the glabella at the mid-anterior part of the frontal lobe. The anterior portion of the frontal glabellar lobe comprises two fore parts of librigenae and a dual frontal glabellar spine. The dual frontal glabellar spine, i.e., the dorsal-rostral plate, is located in the front of the glabella on the dorsal shield. The axial furrows join the marginal furrow at the antero-lateral edge of the cephalon, lacking the preglabellar furrow. The glabellar is contracted at its posterior, but the anterior is expanded and flattened.In the posterior part of the glabella,there are three pairs of glabellar furrows,of which the two posterior pairs go across the glabellar and the anterior pair is discontinuous.The cephalon is smooth anteriorly, tuberculate proximally and pitted laterally, with regularly triangular short spines on the margin. The hypostoma is pentagonal in outline, with a convex median body and distinct rhynchos. The thorax is quadrate in outline,wider than long,and composed of 11 segments.The 7th segment is a macropleura which expands distally and ends in a posteriorly extending macropleural spine.The pygidium is comparatively large and triangular in outline, with more than 40 axial rings and about 15—16 pleural ribs. A narrow doublure lies under the fine posterior pleural spines, lacking a marginal border. The present Coronocephalus gaoluoensis, in terms of its pattern of facial suture, is almost identical with Coronocephalus rex and Senticucullus.They may all be assigned to a distinctive subfamily of Encrinuridae. " RESTUDY OF CORONOCEPHALUS GAOLUOENSIS WU,1979 - CHEN Gui-ying et al. Acta Palaeontologica Sinica 2011-03

Hope all these helps.



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