• Intestine convoluted
• Female: antennal setae formula 0-0-0-3 / 0-0-3, spine formula 0-1-0-1 / 0-0-1
• Posterior portion of valves narrowed to form a tube like structure
• Antennule long and slender, with a single basal sense hair and 3 conspicuously long olfactory setae
• Postabdominal claw with two basal spines
• Postabdomen long, slender, and feebly armed
• Carapace "dirty"

• Reported from Maine and New Hampsire (2), Pennsylvania (3), and the Canadian Maritime Provinces (1).

• Weedy shallows with flocculent bottom material (2)(3).

• Feeds on flocculent and finely particulate detritus which is collected by the first trunk limbs (3).  

• Parophryoxus tubulatus has the ability to swim freely but feebly. It will seldom swim unless disturbed and then it will only move a short distance. An interesting observation made by Fryer (1974) regarding locomotion: "Geometrically the posterior portion of the chamber is thus bilaterally compressed cone terminating in a tube through which the exhalent current is discharged with considerable velocity. This removes faeces discharged within the carapace chamber (an unusual feature) and is associated with the discharge of small quantities of material at frequent intervals, but may have other functions. If the respiratory current flows as the animal swims it must, by jet-propulsion, inevitably lend some slight assistance to the antennae."

• When settled on the substrate locomotion is accomplished by a rowing movement of the antennae. The sparsely armed postabdomen is not adapted for pushing and it does not appear to be used to assist locomotion (3).

(1) DODSON, S.I., and D.G. FREY. 1991. Cladocera and Other Branchiopoda, p. 723-786. In J.H. THORP and A.P. COVICH [eds.], Ecology and Classification of North American Freshwater Invertebrates. Academic.

(2) DOOLITTLE, A. 1911. Descriptions of recently discovered Cladocera from New England. Proc. U.S. Nat. Mus. 41: 161-170.

(3) FRYER, G. 1974. Evolution and adaptive radiation in the Macrothricidae (Crustacea: Cladocera): a study in comparative functional morphology and ecology. Philos. Trans. R. Soc. Lond., B, Biol. Sci. 269: 137-274.