Praeneodiscus, Vachard, Krainer & Lucas, 2015

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 : 56

Genus PRAENEODISCUS n. gen.

zoobank.org/ AABE7958-7961-4CFD-90FB-4FD54D6E34B1

Type Species. Praeneodiscus convexus n. gen. n. sp.

Etymology. Before (= prae) Neodiscus , similar genus.

Synonyms. Hemigordius sensu Grozdilova, 1956 ; Hemigordius (partim) sensu Filimonova, 2008, 2010; Midiella (partim) sensu Blajezowski, 2009.

Diagnosis. Test ovoid. Oscillating, involute coiling. Proloculus spherical followed by a tubular chamber in which lumina are initially semicircular and then ogival.

Composition. Praeneodiscus convexus n. gen. n. sp.; P.? transitus n. gen. n. sp.; P. lipinae ( Lipina, 1949) (= Glomospira? compressa Lipina, 1949 (plate 3, figures 1, 2; plate 7, figure 1) preoccupied by G. compressa Waters, 1928 as indicated by Rich, 1980); Glomospira? miranda Lipina, 1949 ; Hemigordius ovatus Grozdilova, 1956 ; H. longus Grozdilova, 1956 ; H. permicus Grozdilova, 1956 ; H. sp. sensu Zolotova and Baryshnikov, 1980; H. guandongensis sensu Lin et al., 1990 ; Neodiscus sp. A sensu Kobayashi, 1997 (plate 4, figure 10); Agathammina sp. A sensu Kobayashi, 2001 (plate 2, figure 2);? Hemigordius sp. 4 sensu Krainer et al. (2003, plate 6, figure 34);? Agathammina ? sp. A sensu Kobayashi, 2004 (figure 7. 21); Neodiscus orbicus sensu Gu et al. (2005 , plate 1, figure 9); Pseudoagathammina regularis sensu Filomonova, 2008 non Lipina, 1949 nec auctorum; P. dublicata sensu Filomonova, 2008 non Lipina, 1949 nec auctorum; Midiella ? n. sp. sensu Krainer et al. (2009, plate 4, figures 1, 2, 3); Neodiscus plectogyraeformis sensu Song et al. (2009 , figure 8.35-37).

Comparison. The new genus differs from Neodiscus Miklukho-Maklay, 1953 by less ogival lumina, smaller dimensions and less whorls and the difference of age ( Neodiscus is Midian-Lopingian in age). In fact, after the work of Miklukho-Maklay (1953), little unquestionable material of this genus has been published, and many misinterpretations have been made. The best re-illustrated material is that of Kobayashi (2006, figure 4.1-13, 4.21) under the name of Neodiscus padangensis (Lange) . It is relatively similar to our new genus; compare in particular the holotype of Praeneodiscus convexus n. sp. ( Figure 19.4 ) with the specimen of Kobayashi (2006, figure 4.5).

The new genus differs from Glomomidiella in the more ovoid to lenticular test, and coiling oscillating to terminally planispiral and not streptospiral. It differs from Uralogordius Gaillot and Vachard, 2007 which possesses the same shape of lumen, because this latter is entirely planispiral. It differs from Pseudoagathammina Lin, Li and Sun, 1990 by a more regular test and the absence of miliolid coiling. It differs from Hemigordius Schubert, 1908 by the type of coiling, the larger dimensions and the ogival lumen (semicircular in Hemigordius sensu stricto). All the subspecies of Hemigordius quinglongensis (Wang, 1976) orth. mut. (i.e., with “qu” more consistent with the Latin spelling) - quinglongensis , forma (sic), laxa and minima - belong to either Praeneodiscus or Neodiscus .

Among the specimens of Lin, Li and Sun (1990), Neodiscus ovatus (Grozdilova) more resembles Neodiscus milliloides Miklukho-Maklay, 1953 , whereas Neodiscus paraovatus Lin, Li and Sun, 1990 is more similar to true Praeneodiscus ovatus .

Occurrence. Rare in Kungurian (late Leonardian) beds of New Mexico. Early Permian of Japan. Late Early Permian of Bashkorotostan ( Russia). Middle-Late Permian of Tethys and Japan.

Figures

FIGURE 19. 1-2, 4-6, 9. Gymnocodium? johnsonii n. sp. 1. Subaxial section. San Andres Fm. Sample SAR 2-1. 2. Tangential section. San Andres Fm. Sample SAR 2-2. 4. Subaxial section. San Andres Fm. Sample SAR 2-3. 5. Tangential section. San Andres Fm. Sample SAR 2-4. 6. Subaxial section. San Andres Fm. Sample SAR 7-9. 9. Subaxial section. San Andres Fm. Sample SAR 8a-25 (already illustrated in Brose et al., 2013, figure 6.9). 3, 7-8, 10-16. Gymnocodium? bacillum n. sp. 3. Oblique subaxial section. San Andres Fm. Sample SAR 2-5. 7. Subaxial section. San Andres Fm. Sample SAR 8a-3. 8. Axial section. San Andres Fm. Sample SAR 8a-26. 10. Axial section. Yeso. Sample MG(2) 12-2 (already illustrated in Lucas et al., 2013b, figure 8D). 11. Axial section. San Andres. Sample SAR 8-8. 12. Axial section. San Andres Fm. Sample SAR 13-6. 13. Subaxial section. San Andres Fm. Sample SAR 8a-16. 14. Subaxial section. San Andres Fm. Sample SAR 8a-15. 15. Two tangential sections. San Andres Fm. Sample SAR 7- 8. 16. Subaxial section. San Andres Fm. Sample SAR 8a-23.