Syllipsimopodi
extinct genus of cephalopod
Syllipsimopodi is an extinct member of the cephalopod subclass Coleoidea originally interpreted to belong to the clade Vampyropoda, which includes octopuses (Octopoda) and vampire squids (Vampyromorphida). The type and only known species is Syllipsimopodi bideni, named in honor of US President Joe Biden, and to raise awareness of his climate change policies. The holotype fossil was found in the Bear Gulch Limestone deposit in the US state of Montana in 1988, and donated that year to the Royal Ontario Museum by B. Hawes, designated ROMIP 64897. The species lived during the (Carboniferous) Mississippian subperiod, 330.3 to 323.4 million years ago, pushing back the group of cephalopods by 81.9 million years.
Taxonomy
A subsequent study doubted the assignment of Syllipsimopodi to Vampyropoda and suggested it to be a junior synonym of Gordoniconus beargulchensis. The original authors still consider it to be a separate genus and species but suggested further analyses might be needed to firmly place it in Vampyropoda.
Description
Individuals were 12 cm (4.7 in) long and had 10 arms with suckers, with two of the arms being longer than the others. It is currently considered the oldest known vampyropod by some but certainly the oldest known cephalopod with biserial suckers on its ten robust appendages. The lead author of S. bideni states that it is possibly the only known vampyropod - if it really can considered one - that has 10 functional appendages, with all other species having eight arms, suggesting that their ancestors had ten arms. The arms measure to about ~2.1 to 2.4 mm wide at the midlength.
“Syllipsimopodi” enters the record as extinct genus of cephalopod. Crown Archives preserves that source wording while asking what Syllipsimopodi, extinct and genus can confirm, complicate or overturn.
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“Syllipsimopodi” is worth following because a concise public description often conceals a longer documentary argument. Here, Syllipsimopodi, extinct and genus provides the most credible route into that argument.
The date and method of observation matter as much as the stated conclusion, especially where classification or consensus has changed. The source revision retrieved here is dated Sep 12, 2025. The linked authority identifier is Q111158479. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1988.
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This entry incorporates text from “Syllipsimopodi” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.