Ooedigera

The genus name Ooedigera derives from Ancient Greek ooedis "egg-shaped/oval" and geros "old". The species name peeli is in honour of Professor John S. Peel from the Geological Survey of Greenland, who especially researched the locality Ooedigera was discovered in. ==Taxonomy==

in the Early Cambrian The type specimen MGUH 29279 was discovered in the Early Cambrian Sirius Passet Lagerstätte of the North Greenlandic Buen Formation. The area corresponds to the early Cambrian Stage 3 about 519–516.5 million years ago. The specimen is a flat compression fossil preserved in fissile mudstone, with an odd, thin lamination, and several small splotches which represent the remains of various other creatures, such as sponges and trilobites.). The taxonomic position of Vetulicolia continues to be debated, but recent theories place it among the Chordata, either as the most basal portion of the stem group, or close to the Tunicata. ==Anatomy==

The type specimen is long in total, and the body plan is divided into an ovoid front body and a segmented tail. The type specimen seems to have been compressed on its side during fossilization, and due to the irregular folding of the outline, the skin may have been softer than in other vetulicolians. The front body was oval-shaped, measuring in length and in height, and flattened horizontally. It had a straight front edge, and the back edge came to a point, intersecting at the midline of the front body. Unlike Chinese vetulicolians, the type specimen shows no indication of a ridge running along the midline, and a lack of such in Ooedigera would be significant in terms of its taxonomy, but more specimens are required to confirm this. Like other vetulicolians, the midline had 5 more or less evenly spaced openings, from the front edge and from the back edge, corresponding to gill pouches. The front body seems to have had a reticulated or anastomosing pattern. Such ornamentation is also seen Beidazoon, which is of similar size to juvenile specimens of Vetulicola; no ornamented forms of size similar to other adult vetulicolians had been found prior to Ooedigera. Like other vetulicolians, the tail was asymmetrical, flattened horizontally, and divided into 7 segments which were connected by flexible membranes, the latter allowing movement. It is long and high. Each segment had concave edges, which gave each one an hourglass shape in side-view. Segments 2–7 were flat on the underside, and segments 5–7 were also flat on the top. The last segment was shorter than in other vetulicolians. Given the asymmetrical flattening, the tail likely propelled by flexing side-to-side like a fish rather than up-and-down. ==Palaeocology==

It is largely unknown what vetulicolians fed upon. Lacking mouths adapted for chewing or grasping, they were probably not predators or scavengers. Lacking limbs, it is unlikely they were burrowers or lived on the seafloor, rather inhabiting the water column (nektonic) but perhaps staying near the seafloor (nektobenthic). They may have been passive floaters, but it is possible that the gills were used for jet propulsion like thaliaceans. About 45 species have been discovered in Sirius Passet, mostly endemic fauna, including trilobites, sponges, worms, and the extinct halkieriids and lobopodians. ==References==