Biology:Orstenotubulus

Orstenotubulus is a genus of minute lobopodian known from three-dimensionally preserved remains found in the Upper Cambrian (Furongian) Orsten deposits of southern Sweden.

Morphology

Orstenotubulus was tiny, estimated to only be 4–5 millimetres (⁵⁄₃₂–³⁄₁₆ in) long, with elongated, thin body about 0.12–0.205 millimetres (¹⁄₂₀₀–¹⁄₁₂₅ in) wide with pairs of upward-pointing spines running down the entire top of the body. Each pair of spines was associated with a pair of relatively elongate legs, with the whole body suggested to have 9-10 spine-leg pairs. The body was weakly annulated. It had tiny retractable spines ventral to the leg surface.

Ecology

Orstenotubulus is thought to have lived by walking on the seafloor, with its spines likely serving to protect it against predators.

Taxonomy

A 2015 study found that it was within the "hallucishaniid" grouping of lobopodians, related to lobopodians like the also spined Hallucigenia and Collinsovermis.

 Phylogeny of Panarthropoda and lobopodians after Knecht et al. 2025:

†Diania 80px       †Lenisambulatrix 80px         †Paucipodia 80px       †Thanahita 80px     †Eoconchariidae   †Microdictyon 80px     †Fusuchoncharium     †Quadratapora           †Xenusion 70px     †Onychodictyon 80px         †Strictocorniculum     †Rhombocorniculum     †Orstenotubulus90px     †Carbotubulus     †Hallucigenia fortis     †Hallucigenia sparsa 60px       †"Hallucigenia" hongmeia       †Cardiodictyon 80px       Tardigrada (tardigrades) 60px   †Luolishaniida     †Ovatiovermis 60px     †Facivermis 70px         †Luolishania 80px   †Collinsovermidae   †EBS Collinsovermid (SAM P14848)       †Acinocricus       †Collinsovermis 80px       †Collinsium 90px     †Entothyreos 60px                                 †Aysheaiidae   †Aysheaia 80px       Soom Shale lobopodian (C1947)       †Hadranax 80px     †Palaeocampa 80px         Antennopoda     †Antennacanthopodia 80px   Onychophora   †Antennipatus     †Cretoperipatus 80px     †Helenodora 90px     Living onychophorans 80px   (velvet worms)     †Siberiidae   †Siberion 80px     †Megadictyon 80px     †Jianshanopodia 80px           †Pambdelurion 80px     †Kerygmachelidae 80px         †Opabiniidae 80px       †Radiodonta (e.g. Anomalocaris) 80px     Deuteropoda (modern arthropods) 70px

References

Template:Lobopodia Wikidata ☰ Q15710931 entry