Genus Puytoracia Bonnet, 1970
Diagnosis: Shell ovoid, elongated, rather close to that of Trinema enchelys. Ventral side slightly flattened, dorsal surface domed. Pseudostome of the plagiostome type, with the opening in the plane of the ventral surface or in a very slightly oblique plane with respect to the latter. Pseudostome circular or slightly elliptical. In the latter case, the pseudostome’s major axis is perpendicular to that of the test. The pseudostome is bordered by a row of about twenty sub-circular, nested scales, each bearing a strong central rectilinear denticulation bordered by two denticles which are at the limit of visibility under a light microscope. The typical thorny chitinoid necklace of the genus Trinema seems to be lacking. Shell consisting of siliceous, endogenous, hyaline, elliptic scales, separated, very rarely joined (and then without appreciable superposition). Free space occupied by a second series of much smaller scales and also elliptic. There may be a very slight overlap between small and large scales, but in general, the contact seems to be punctual. Colorless hyaline cement.
Remarks. Puytoracia is distinguished by large elliptical body scales. Bonnet (1970) added a second key character (translated from French): “[scales are] separated, very rarely joined, and without clear overlap. The free space is occupied by a second series of scales, much smaller and also elliptical. These small and large scales may overlap very slightly but, in general, the contact seems punctual.” However, Nicholls (2006) mentioned that the “most important criterion for separating Puytoracia from some Trinema species are the large elliptical scales.” This is also mentioned as the only characteristic by Santibáñez et al. (2011). Interestingly, neither author mentioned the second character as being a distinguishing feature. A Puytoracia bergeri illustrated by Santibáñez et al. (2011) has large overlapping oblong scales without any free space occupied by smaller scales and is therefore definitely not a Puytoracia.
References: Bonnet, L., 1970. Nouveaux Thécamoebiens du Sol, Bull. Soc. Hist. Nat. Toul.,106:3-4