Mollisonia

Mollisonia
Temporal occurrence
	lower to middle Cambrian
	515 to 500 million years
Locations
	North America; China;
Systematics
Trunk :	Arthropod (arthropoda)
	incertae sedis
Order :	Mollisoniida
Family :	Mollisoniidae
Genre :	Mollisonia
Scientific name of the order
	Mollisoniida
	Simonetta & Delle Cave , 1975
Scientific name of the family
	Mollisoniidae
	Simonetta & Delle Cave , 1975
Scientific name of the genus
	Mollisonia
	Walcott , 1912

Mollisonia is an extinct genus with an uncertain position within the arthropods (Arthropoda).

features

Representatives of the genus Mollisonia were elongated, almost rectangular in the dorsal and almost triangular in the transverse view. The dorsal exoskeleton , consisting of a head shield, seven thorax segments ( tergites ) and a tail shield , had an axial crest. The thorax segments were all roughly the same in length and width. The tail shield had two or three pairs of transverse extensions on the surface.

Limbs have not been preserved.

Locations

Species of the genus have been found in the Burgess Shale in Canada , the Kaili Formation in China, and the Wheeler Formation in Utah , United States .

Systematics

Mollisonia shows some similarities with Corcorania Jell, 1980 , Kuamaia Hou, 1987 and Sinoburius Hou, Ramsköld & Bergström, 1991 , but not with Xandarella Hou et al., 1991 , which Hou and Bergström, however, placed the latter two in the same subclass Petalopleura . However, since the extremities are missing in all finds, Mollisonia could not yet be classified precisely. Simonetta and Delle Cave placed them in 1975 in the monotypical order Mollisoniida with the family Mollisoniidae.

There are currently three types:

Mollisonia gracilis Walcott, 1912
Mollisonia sinica Zhang et. al, 2002
Mollisonia symmetrica Walcott, 1912 ( type )
(= Mollisonia rara Walcott, 1912)

swell

literature

Zhang X.-L., Zhao Y.-L., Yang R.-D., Shu D.-G .: The Burgess Shale arthropod Mollisonia (M. sinica new species): New occurrence from the middle cambrian Kaili fauna of southwest China . Journal of Paleontology 76 (6), 2002: 1106-1108. HTML

Individual evidence

^ DEG Briggs, BS Lieberman, JR Hendricks, SL Halgedahl, RD Jarrard: Middle Cambrian Arthropods from Utah . Journal of Paleontology 82 (2), 2008: 238-254. HTML
↑ GD Edgecombe, L. Ramsköld: Relationships of cambrian arachnata and the systematic position of trilobita . Journal of Paleontology 73 (2), 1999: 263-287. PDF
^ ^A ^b A. M. Simonetta, L. Delle Cave: The Cambrian non-trilobite arthropods from the Burgess Shale of British Columbia - a study of their comparative morphology, taxonomy and evolutionary significance . Palaeontographia Italics 69, 1975: 1-37.

[Briggs-1] DEG Briggs, BS Lieberman, JR Hendricks, SL Halgedahl, RD Jarrard: Middle Cambrian Arthropods from Utah . Journal of Paleontology 82 (2), 2008: 238-254. HTML

[Edgecombe-2] GD Edgecombe, L. Ramsköld: Relationships of cambrian arachnata and the systematic position of trilobita . Journal of Paleontology 73 (2), 1999: 263-287. PDF

[Simonetta-3] A ^b A. M. Simonetta, L. Delle Cave: The Cambrian non-trilobite arthropods from the Burgess Shale of British Columbia - a study of their comparative morphology, taxonomy and evolutionary significance . Palaeontographia Italics 69, 1975: 1-37.