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Tetragraptus quadribrachiatus
Order: Graptolite
Genus: Tetragraptus Species: Tetragraptus quadribrnchiatus Location found: Aorangi Mine, Nelson Region |
For those whose Greek and Latin are a little rusty, the name Tetragraptus quadribrachiaptus roughly translates as 'Four-limbed graptolite with four arms', which fairly precisely describes this species.
Along with other graptolites, it is an important index fossil for the early Ordovician, and thus helps to fix the deposits in the Aorangi Mine area to that stage. It is also notable that graptolites had an almost global distribution, so the same, or closely related, species are found across the world. This species, for example, is also known from the Nevada and Idaho area the USA, the Yukon area of Canada, Latvia in northern Europe, and the St Petersburg area of Russia, even though these areas were far removed from Zealandia in the Ordovocian. A specimen of Isograptus vicctoriae is also visible in the top left corner of the sample. This is a common associate of T. quadibrachiatus in the Aorangi Mines area, along with Dichograptus sp.(see image, right). |
Mixed assemblage including Isograptus victoriae, Dichograptus sp. and Tetragraptus quadribranchiatus.
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