MICROMAIINAE Beurlen, 1930

Schweitzer, Carrie E. & Feldmann, Rodney M., 2010, New fossil decapod crustaceans from the Remy Collection, Muséum national d’Histoire naturelle, Paris, Geodiversitas 32 (3), pp. 399-415 : 407

Subfamily MICROMAIINAE Beurlen, 1930

DISCUSSION

Beurlen (1930) provisionally united the genera Micromaia Bittner, 1875 , Mithracia Bell, 1858 and Pisomaia Lőrenthey in Lőrenthey & Beurlen, 1929, within the subfamily Micromaiinae .Th e basis for this placement is not clear and the comparison of referred taxa suggests that they bear little resemblance to one another. Th e conformation of axial regions on the type species of the three genera are totally different from one another; the outlines, particularly with reference to the posterior margin are dissimilar; and the orbital architecture of the two taxa on which it is present on the type species, Micromaia tuberculata Bittner, 1875 , and on Pisomaia tuberculata Lőrenthey in Lőrenthey & Beurlen, 1929, are different. Thus, there seems to be no unifying set of morphological criteria to justify the Micromaiinae .Further, Glaessner (1969) characterized the orbital structure of the subfamily as being like the Inachinae which he described as lacking orbits. That is certainly not the case in the several examples of Micromaia examined by us and well illustrated by Beschin et al. (1985). Investigation into the composition and validity of the subfamily is ongoing.

Discussion of the Micromaiinae is warranted because the type species of the new genus, Planobranchia n. gen., was originally placed within Micromaia . As discussed below, the species referred to the new genus bear close resemblance to members of the Majinae , and that placement is adopted here. Because we have not examined all available representative specimens of all species of Micromaia , Mithracia , and Pisomaia , it is premature to comment on their relationships in detail. Th at work is in progress.