Pseudonumoloculina kalantarii, Schlagintweit & Rashidi, 2016

Schlagintweit, Felix & Rashidi, Koorosh, 2016, Some New And Poorly Known Benthic Foraminifera From Late Maatrichtian Shallow-Water Carbonates Of The Zagros Zone, Sw Iran, Acta Palaeontologica Romaniae 12 (1), pp. 53-70 : 61-65

Pseudonumoloculina kalantarii n. sp.

Fig. 15 Holotype: Slightly oblique axial section of a juvenile specimen (showing notched aperture) illustrated in Figure 15k (and detail in Fig. 15n ). Thin-section NG 85.

Origin of the name: The species name is dedicated to Amir Kalantari, micropalaeontologist of the National Iranian Oil Company for his contributions to the micropalaeontology of Iran.

Type locality: Naghan section (see Fig. 2 )

Type level: Late Maastrichtian of the Tarbur Formation.

Diagnosis: Representative of Pseudonummoloculina with egg-shaped, slightly biumbilicate test, and rounded margin. The test is streptospirally coiled initially (3 to 4 whorls) then oscillating to almost planispiral (up to 5 whorls). Chambers elongated along the coiling, low and only gradually increasing in height.

Description: Test ovate, with slight biumbilical depression and broadly rounded periphery. First whorls streptospirally coiled, later planes of coiling become more and more regular to almost planispiral, resulting in an overall sigmoid arrangement when observed in axial sections ( Fig. 15h ). Septa inclined and rather short delimiting chambers that are greatly elongated along the coiling direction and that only gradually increase in height. Number of chambers per whorl unclear. Wall calcareous imperforate, porcelaneous, possibly with some incorporated (agglutinated) grains (e.g., Fig. 15j, g ). Foramina and aperture with numerous short notches, irregular in shape, protruding from the chamber roof and floor ( Fig. 15l–n ) Dimensions (in mm):

Equatorial diameter (ed): up to 2 mm

Axial diameter (ad): up to 0.9 mm

Ratio ad/ed: 0.6 to 0.7

Comparisons: The differences to the other species of Pseudonummoloculina can be summarized as follows. Pseudonummoloculina aurigerica Calvez, 1988 (Albian of Spain): The planispiral stage of the type-species is reduced with only 1 ½ to 2 ½ whorls compared to up to 5 in P. kalantarii . Also the size is reduced (ed up to 1.3 mm, ad up to 0.73 mm).

Pseudonumoloculina heimi ( Bonet, 1956) (Cenomanian of Mexico): With its numerous whorls (up to 5), and size (ed up to 2.16 mm), P. heimi is close to P. kalantarii . P. heimi is different from the former in its compressed discoidal test (ratio ad/ed 2.45 to 3.6, as measured from Conkin and Conkin (1958, fig. 1-25).

Pseudonummoloculina robusta ( Torre, 1966) (Coniacian or Santonian of Italy): In P. robusta , wall thickness nearly equals the width of the chamber lumen, given rise to the species name. With maximum size of 1.025 mm, P. robusta is much smaller than P. kalantarii . A further difference is the inclination of the axes of successive chamber within a whorl as discernible in equatorial sections ( Torre, 1966, pl. 3, fig. 3) whereas in P. kalantarii they are more or less in line.

Pseudonummoloculina sopadensis Drobne, Premru & Ogorelec, 2005 , nom. nud. (Thanetian of Slovenia): In a congress abstract, Drobne et al. (2005) introduced the new species Pseudonummoloculina sopadensis (with test sizes of up to 1.5 mm) from the Thanetian of Slovenia. So far no valid description and typification were provided and therefore currently the taxon fails to confirm to article 13 of the International Code of Zoological Nomenclature (= nomen nudem). Nonetheless, P. sopadensis was included in the list of the shallow benthic zones, respecttively SBZ 2 to 3 of Serra-Kiel et al. (1998), noting a forthcoming description. In this connection reference was made to Dieni et al. (1985, pl. 17, fig. 7). One illustration of this taxon can be found in Drobne and Cosovic (2009, fig. 4, Pseudonummoloculina n. sp.). A difference of P. sopadensis to P. kalantarii might be the reduced size, and test morphology indicated as spherical to slightly nautiloid in Drobne et al. (2005).

Figures

Fig. 15 Pseudonummoloculina kalantarii n. sp., Late Maastrichtian Tarbur Formation of Naghan section, Zagros Zone, SW Iran. a–b Equatorial sections. c–d, f–g, j Oblique sections. e, h–i, k Oblique axial to subaxial sections. l–n Details from i–k showing notched aperture in the last whorls. Holotype specimen in k (detail in n). Notched apertures are also discernible in d and f (arrows), and a?. Thin-sections: TB 82 (a), NG 81 (b), NG 83 (c, h–i, l), NG 86 (d), NG 83-2 (e–f, j, m), NG 85 (g, k, n).

Fig. 2 Location map of the studied area.