Paraleptomitella Chengjiang Biota Demosponge Fossil

Paraleptomitella dictyodroma

Phylum Porifera, Demospongia

Geological Time: Early Cambrian (~525 million years ago)

Size: 77 mm long and 10 mm across

Fossil Site: Chengjiang Maotianshan Shales, Quiongzhusi Section, Yu’anshan Member, Heilinpu Formation, Ercaicun Village, Anning, Kunming, Yunnan Province, China

Paraleptomitella dictyodromaDescription: This near-complete sponge known as Paraleptomitella dictyodroma comes from the Chengjiang Biota. The diversity of soft-tissue fossils is astonishing:Demosponge algae, medusiforms, sponges, priapulids, annelid like worms, echinoderms, arthropods (including trilobites), hemichordates, chordates, and the first agnathan fish make up just a small fraction of the total. Numerous problematic forms are known as well, some of which may have represented failed attempts at diversity that did not persist to the present day.

The species grew to a maximum known height of 10 cm and width of 12 mm, so this one is a typical example. The narrow base of the sponge is indicative of its presumed attachment to the sea floor. This demosponge is similar to Leptomitella (hence the genus name), and is known only from the Chengjiang Biota.

Also see: Chengjiang Biota List Chengjiang Fossils

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