Kerygmachela kierkegaardi is a member of Sirius Passet fauna, and a species of the Cambrian lobopodians 1), 4).
The Sirius Passet Lagerstätte of north Greenland is the Lower Cambrian(515-518 Million years ago) fossil-rich sedimentary deposit which located on the northern margin of Laurentia, near the equartor, at palaeolatitude of around 15° S. The Sirius Passet Lagerstätte is older than the Burgess Shale 3).
The head region of Kerygmachela is a rounded lobe-like shape with a pair of frontal appendages bearing long spinous processes 2), 4). A pair of sickle-shape eyes, interpreted as primitive compound eyes, is located under the frontal appendages, on the ventro-lateral position of head, and a mouth-opening is situated on the ventral region of anterior lobe, between a pair of the frontal appendages 4).
Kerygmachela has eleven pairs of lobe-shaped lateral flaps with gills and lobopodous limbs, and has a single long tail spine 2), 4). The trunk and the tail are about 7 cm in length, total length of the body , including with the frontal appendages, will be approximately 20 cm (measured on Figure 1 of the reference 4).
Presumably, Kerygmachela had swum using the lateral-lobes. The frontal appendages are slightly curved inwards, then Kerygmachela might have grasped a prey using them like a forcep, or again, stirred up sediment and swept/scooped benthonic small animals and the organic detritus.
- Budd G (1993) A Cambrian gilled lobopod from Greenland. [abstract] Nature 364: 709-711. (DOI:10.1038/364709a0.)
- Budd GE (1998) The morphology and phylogenetic significance of Kerygmachela kierkegaardi Budd (Buen Formation, Lower Cambrian, N Greenland). [abstract] Earth.Env.sci.T.R.So. 89(4): 249–290. (DOI:10.1017/S0263593300002418.)
- Harper DAT, Hammarlund EU, Topper TP, Nielsen AT, Rasmussen JA, Park TYS, Smith MP (2019) The Sirius Passet Lagerstätte of North Greenland: a remote window on the Cambrian Explosion. J. Geol. Soc. 176:1023-1037. (DOI: 10.1144/jgs2019-043.)
- Park TYS, Kihm JH, Woo J, Park C, Lee WY, Smith MP, Harper DAT, Young F, Nielsen AT, V J (2018) Brain and eyes of Kerygmachela reveal protocerebral ancestry of the panarthropod head. (Supplementary Information.) Nat. Commun. 9(1019). (DOI:10.1038/s41467-018-03464-w.)