''Xenusion auerswaldae'' is an early

lobopodian The lobopodians, members of the informal group Lobopodia (from the Greek, meaning "blunt feet"), or the formally erected phylum Lobopoda Cavalier-Smith (1998), are panarthropods with stubby legs called lobopods, a term which may also be used as ...

known from two specimens found in

glacial erratics A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...

on the

Baltic Baltic may refer to: Peoples and languages *Baltic languages, a subfamily of Indo-European languages, including Lithuanian, Latvian and extinct Old Prussian *Balts (or Baltic peoples), ethnic groups speaking the Baltic languages and/or originatin ...

coast of Germany. They probably originated in the Kalmarsund Sandstone of Southern Sweden, which was deposited in the Lower Cambrian (Upper Tommotian–Lower Atdabanian; Stages 2→3). It is the oldest currently known lobopodian with soft body

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

. The specimens are not especially well preserved. The older specimen is 10 cm or so in length with a narrow, weakly segmented body. Assuming it was the posterior section, the specimen was estimated to be part of an animal about 20 cm in length. A depression runs up the bottom on all but the rearmost segments. There is a slightly bulbous termination, and each segment before that seems to have a single pair of tapering annulated legs similar to the modern

onychophoran Onychophora (from grc, ονυχής, , "claws"; and , , "to carry"), commonly known as velvet worms (due to their velvety texture and somewhat wormlike appearance) or more ambiguously as peripatus (after the first described genus, ''Peripatus' ...

, but without specialized feet and claws. More than 10 body segments were present. There is presumably a spine on each body bump and faint transverse parallel striations on the annulations on the legs. The legs of what is possibly the foremost segments are either absent or not preserved. The head is believed to be missing or is poorly preserved. Based on a new specimen that showing the anterior section, it possibly have a long narrow

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular mouthparts used for feeding and sucking. In vertebrates, a proboscis is an elonga ...

. but this also suggested to be a preservational artefact. ''Xenusion'' has been reinterpreted as an

Ediacaran The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and t ...

frond animal by Tarlo, and a drawing of that interpretation has been presented by McMenamin. In a photograph presented in '' The Treatise on Invertebrate Paleontology'' Volume O, the organism's appearance seems to support the original interpretation more. Further studies of Xenusiid close the possibility of a Rangeomorphy affinity.

References

External links

Onychophora: Fossil Record
{{Taxonbar, from=Q136421 Xenusia Terreneuvian first appearances Cambrian Series 2 extinctions Cambrian genus extinctions