MILIOLIDA Lankester, 1885

Vachard, D, Krainer, K & Lucas, SG, 2015, Late Early Permian (late Leonardian; Kungurian) algae, microproblematica, and smaller foraminifers from the Yeso Group and San Andres Formation (New Mexico; USA), Palaeontologia Electronica (English ed.) 3 (8), pp. 1-77 : 36-38

Order MILIOLIDA Lankester, 1885

Remarks. The principal character of the class Miliolata is the porcelaneous wall. This wall, composed of high magnesian calcite, is often unstable, and the typical extant aspect amber-coloured or tan-skinned ( Scholle and Ulmer-Scholle, 2003, p. 41) becomes rapidly and eodiagenetically black, and then, whitish if it is meso- or telodiagenetized in neosparite and/or silica and/or anhydrite ( Vachard et al., 2005, plate. 4, figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17).

When the wall is black, it is strictly identical in optical as well as in electronic microscopy to the originally microgranular wall of a Fusulinata. For instance, our unpublished material of Palaeozoic Miliolata, SEM-observed, is similar in wall aspect to the Fusulinida Eostaffella illustrated by Vachard et al. (2004, plate 1, figure 2). The argument of Pronina (1994) that “Late Permian cornuspirids [which] have microgranular wall structure (...) are considered to belong to genus Pseudoammodiscus ” is therefore irrelevant.

Because it is originally purely calcitic, a microgranular wall remains more stable than a porcelaneous one. Consequently, the difference between some taxa of Miliolata and Fusulinata are not purely dialectic and diagenetic, and cannot be indicated only by arguments of formal logic. That is particularly true for the genus Cornuspira Schultze, 1854 in opposition to the genus Pseudoammodiscus Conil and Lys in Conil and Pirlet, 1970; as well as Hemigordiellina Marie in Deleau and Marie, 1961 sensu Vachard and Beckary, 1991 versus “ Pseudoglomospira ’’ auctorum (non Bykova in Bykova and Polenova, 1955) or Pseudospira Reitlinger in Vdovenko et al., 1993; or Hoyenella Rettori, 1994 emend. Gaillot and Vachard, 2007 versus Glomospirella Plummer, 1945 auctorum; Brunsiella Reitlinger, 1950 versus Brunsia Mikhailov, 1935 ; Palaeonubecularia Reitlinger, 1950 versus Tolypammina Rhumbler, 1895 , etc. Despite the homeomorphy existing between the free bilocular Late Mississippian (Serpukhovian) Pseudoammodiscus and Cornuspira (underlined for example by Tappan and Loeblich, 1988), Gaillot and Vachard (2007) supposed that the phylogenetic change from a microgranular to a porcelaneous wall occurred in a group of attached forms because of: 1) the older appearance of these porcelaneous forms (at the beginning of the Serpukhovian; whereas the FAD of Cornuspira would be late Serpukhovian in age); 2) the great morphological similarity between attached genera like Scalebrina Conil and Longerstaey in Conil et al., 1980 and Palaeonubecularia ; 3) the dominance of the attached porcelaneous forms during the Bashkirian; 4) the rarity of Cornuspira and Hemigordiellina during the Bashkirian-Moscovian; 5) the FAD of the first genus universally accepted as porcelaneous, i.e., Hemigordius Schubert, 1908 , is during the late Moscovian.

Superfamily?NUBECULARIOIDEA Jones in Griffith and Henfrey, 1875 nom. translat. Mikhalevich, 1988

Family? CALCIVERTELLIDAE Loeblich and Tappan, 1964 nom. translat. Reitlinger in Vdovenko, Rauzer-Chernousova, Reitlinger and Sabirov, 1993 emend. Gaillot and Vachard, 2007

Description. Attached bilocular, undivided, tubular genera separated by the type of coiling and/or the thickness of the wall. Porcelaneous wall often neosparitized. Aperture terminal, simple.

Occurrence. Serpukhovian-Recent, cosmopolitan.