Molaria

Molaria
Temporal range: Cambrian Series 2–Burgess Shale
Molaria spinifera in dorsal and lateral views from a plate in Walcott, 1912
Molaria spinifera life restoration
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
(unranked): †Artiopoda
Genus: †Molaria
Walcott, 1912 [1]
Type species
Molaria spinifera
Walcott, 1912
Other species

Molaria steini Peel, 2017

Additional specimens from 1912 plate

Molaria is a genus of Cambrian arthropod, the type species M. spinifera is known from the Middle Cambrian Burgess Shale. 144 specimens of Molaria are known from the Greater Phyllopod bed, where they comprise 0.27% of the community.[2] A second species M. steini was described from the Sirius Passet in Greenland in 2017.[3]

The body of Molaria consisted of a head shield (cephalon), a trunk consisting of eight sections (tergites), and a telson, which included a short ventral spine and a long posterior spine. Three pairs of legs were beneath the cephalon and another eight pairs were attached to the trunk. Eyes were lacking, but a pair of short antennae was present on the cephalon. Specimens of Molaria ranged from 8 to 26 mm in length from cephalon to telson, with the posterior spine slightly longer than the body length.[4] Molaria was superficially similar to Habelia, another Burgess Shale arthropod with a long tail spine, but which possessed 12 trunk tergites.[4] It is currently considered a member of Artiopoda.[3]

The genus name derives from "Molar", the name of a mountain peak east of the Valley of the Ten Peaks in Alberta, Canada.[1]

  1. ^ a b Walcott, C. D. (1912). "Middle Cambrian Branchiopoda, Malacostraca, Trilobita and Merostomata". Smithsonian Miscellaneous Collections. 57: 145–228.
  2. ^ Caron, Jean-Bernard; Jackson, Donald A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS. 21 (5): 451–65. Bibcode:2006Palai..21..451C. doi:10.2110/palo.2003.P05-070R. JSTOR 20173022. S2CID 53646959.
  3. ^ a b Peel, J.S. (2017-06-30). "Molaria (Euarthropoda) from the Sirius Passet Lagerstätte (Cambrian Series 2, Stage 3) of North Greenland". Bulletin of Geosciences: 133–142. doi:10.3140/bull.geosci.1658. ISSN 1802-8225.
  4. ^ a b Whittington, H. B. (1981). "Rare Arthropods from the Burgess Shale, Middle Cambrian, British Columbia". Philosophical Transactions of the Royal Society B: Biological Sciences. 292 (1060): 329–357. Bibcode:1981RSPTB.292..329W. doi:10.1098/rstb.1981.0033.