HEMIGORDIIDAE Reitlinger

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 : 50-52

Family HEMIGORDIIDAE Reitlinger in Vdovenko, Rauzer-Chernousova, Reitlinger and Sabirov, 1993 Genus HEMIGORDIUS Schubert, 1908

Type Species. Cornuspira schumbergeri Howchin, 1895 .

Description. Test free. Proloculus followed by a tubular, undivided chamber. Coiling initially streptospiral, more or less protuberant in the central part of the test, followed by a discoid planispiral involute part to occasionally semi-evolute or evolute in the last whorl. Lumen at the concavus stage. Wall porcelaneous, generally recrystallized as a dark microgranular one. Aperture at the end of the tubular chamber.

Remarks. There are probably five lineages of Hemigordius sensu lato. The first one has its FAD in North America ( Groves, 1984) with H. harltoni Cushman and Waters, 1928a and then migrates at the end of the Moscovian into the Urals and Tethys with H. discoideus (Brazhnikova and Potievskaya, 1948) and H. simplex ( Reitlinger, 1950) . These primitive forms gave rise to the type species of the genus, H. schlumbergeri ( Howchin, 1895) , which is Late Pennsylvanian-Early Permian in age. This species generated a plexus of hemigordiids with an important marker Rectogordius Alipour and Vachard in Alipour et al., 2013 (= false Neohemigordius of the authors). Then, another lineage started with H. schlumbergeri sensu Foster et al. (1985 ; to rename) where the chamber lumina became concavus-angulatus to angulatus in shape (see below for the discussion of these terms); this latter taxon generated various Neodiscidae Lin, 1984 nom. translat. Gaillot and Vachard, 2007, especially in this study Glomomidiella and Praeneodiscus n. gen. (or Uralogordius in the Urals).

The fifth lineage during the Middle Permian is more poorly known, but it displays diversified small forms showing: 1) a long, semi-evolute to evolute secondary stage ( Okimuraites Reitlinger in Vdovenko et al., 1993 = Discospirella Okimura and Ishii, 1981 homonym of Discospirella Loeblich and Tappan, 1961 =? Brunsispirella , according to Nestell et al., 2009); 2) entirely planispiral forms ( Arenovidalina sensu Sosnina, 1977 (non? Ho, 1959); see also some unnamed taxa in Berczi-Makk et al., 1995 from the Wuchiapingian of Hungary); 3) sigmoidal to planispiral rhombic forms ( Midiella Pronina, 1988 sensu stricto not auctorum); or 4) distally irregularly coiled forms ( Pseudohemigordius Nestell and Nestell, 2006 ). Various forms with pseudosepta are probably related to these different lineages but difficult to link with them: Septagordius Gaillot and Vachard, 2007; Nikitinella Sosnina, 1983 ; Pseudomidiella Pronina-Nestell in Pronina-Nestell and Nestell, 2001, and several atypical Baisalina (non Reitlinger, 1965).

Occurrence. Bashkirian of North America. Cosmopolitan from late Moscovian to latest Permian.