Musacaris

Musacaris is an extinct genus of Cambrian arthropod from the Orsten Lagerstätte, formerly synonymous with Martinssonia. It contains only a single species, Musacaris gerdgeyeri.

Musacaris Temporal range: Upper Cambrian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Genus:	†Musacaris Haug et al, 2010
Species:	†M. gerdgeyeri
Binomial name
†Musacaris gerdgeyeri Haug et al, 2010

Description

Musacaris is a small (roughly 0.8 mm long), unsegmented arthropod, with four pairs of appendages. It has a pair of antennae, and three pairs of biramous appendages.^[1] It also has an unusual projection on its head, possibly the future position of the mouth. The unsegmented body suggests all current specimens of Musacaris may be so-called "head larvae". The five developmental stages are quite similar, with the same amount and positioning of the limbs. Currently, Musacaris is thought to be a basal mandibulate or stem-crustacean, possibly sister to labrophorans (Crustacea and Phosphatocopina).

Distribution

Musacaris is known from thirteen specimens of different larval forms, all from the Orsten Lagerstätte in Sweden,^[1] alongside twenty-one other specimens referred to Martinssonia elongata.^[2]