Foraminifera taxon details
Megacrassispirella Zhang in Zhang et al., 2016 †
1309076 (urn:lsid:marinespecies.org:taxname:1309076)
accepted
Genus
Ammodiscus xarlashanensis Wang, 1986 † accepted as Megacrassispirella xarlashanensis (Wang, 1986) † (type by original designation)
marine, brackish, fresh, terrestrial
fossil only
feminine
Zhang, Y.-C.; Shen, S.-Z.; Zhang, Y.-J.; Zhu, T.-X.; An, X.-Y. (2016). Middle permian non-fusuline foraminifers from the middle part of the Xiala Formation in Xainza County, Lhasa Block, Tibet. <em>The Journal of Foraminiferal Research.</em> 46(2): 99-114., available online at https://doi.org/10.2113/gsjfr.46.2.99
page(s): p. 107 [details] Available for editors
[request]
page(s): p. 107 [details] Available for editors
[request]
Original description Diagnosis. Test has a discoidal shape with a strongly biconcave umbilicus; test consists of a proloculus and an undivided...
Original description Diagnosis. Test has a discoidal shape with a strongly biconcave umbilicus; test consists of a proloculus and an undivided tubular chamber. Coiling is planispiral evolute. The axis of coiling of the initial whorl may deviate with respect to the following planispirally coiled whorls. Wall is porcelaneous, imperforate, and very thick in later whorls.
Comparison. This new genus is characterized by an extremely large size compared to other planispirally coiled foraminifers. The coiling of the proposed genus is quite similar to that of Crassispirella, Cornuspira, Ammodiscus, Pseudoammodiscus, Postcladella, and Forschia. But Megacrassispirella gen. nov. can be distinguished from Ammodiscus by its larger shell and porcelaneous wall. Cornuspira and Postcladella also have planispirally coiled whorls with a porcelaneous wall, but they are much smaller in size and have thinner walls compared with Megacrassispirella. The new genus Megacrassispirella is quite similar to Crassispirella in the style of coiling and wall structure. Although Gaillot & Vachard (2007) noted that Crassispirella produced one of the largest planispiral-evolute tests in the history of the Foraminifera, the tests of Megacrassispirella are two or three times larger than those of Crassispirella. In addition, Megacrassispirella has up to 14 whorls rather than 5–6 whorls in Crassispirella. Megacrassispirella also resembles Brunsispirella in wall structure and planispirally coiled whorls. But, Megacrassispirella is much larger and has a very strongly biconcave umbilicus. Megacrassispirella also resembles Forschia and Pseudoammodiscus in shape, but can be differentiated from the latter two genera by its porcelaneous wall.
Occurrence: Midian, Xainza area of central Tibet.
(Zhang et al. (2016)). [details]
Comparison. This new genus is characterized by an extremely large size compared to other planispirally coiled foraminifers. The coiling of the proposed genus is quite similar to that of Crassispirella, Cornuspira, Ammodiscus, Pseudoammodiscus, Postcladella, and Forschia. But Megacrassispirella gen. nov. can be distinguished from Ammodiscus by its larger shell and porcelaneous wall. Cornuspira and Postcladella also have planispirally coiled whorls with a porcelaneous wall, but they are much smaller in size and have thinner walls compared with Megacrassispirella. The new genus Megacrassispirella is quite similar to Crassispirella in the style of coiling and wall structure. Although Gaillot & Vachard (2007) noted that Crassispirella produced one of the largest planispiral-evolute tests in the history of the Foraminifera, the tests of Megacrassispirella are two or three times larger than those of Crassispirella. In addition, Megacrassispirella has up to 14 whorls rather than 5–6 whorls in Crassispirella. Megacrassispirella also resembles Brunsispirella in wall structure and planispirally coiled whorls. But, Megacrassispirella is much larger and has a very strongly biconcave umbilicus. Megacrassispirella also resembles Forschia and Pseudoammodiscus in shape, but can be differentiated from the latter two genera by its porcelaneous wall.
Occurrence: Midian, Xainza area of central Tibet.
(Zhang et al. (2016)). [details]
Hayward, B.W.; Le Coze, F.; Vachard, D.; Gross, O. (2025). World Foraminifera Database. Megacrassispirella Zhang in Zhang et al., 2016 †. Accessed at: https://www.marinespecies.org/Foraminifera/aphia.php?p=taxdetails&id=1309076 on 2026-03-23
Date
action
by
original description
Zhang, Y.-C.; Shen, S.-Z.; Zhang, Y.-J.; Zhu, T.-X.; An, X.-Y. (2016). Middle permian non-fusuline foraminifers from the middle part of the Xiala Formation in Xainza County, Lhasa Block, Tibet. <em>The Journal of Foraminiferal Research.</em> 46(2): 99-114., available online at https://doi.org/10.2113/gsjfr.46.2.99
page(s): p. 107 [details] Available for editors [request]
page(s): p. 107 [details] Available for editors
[request]From editor or global species database
Original description Diagnosis. Test has a discoidal shape with a strongly biconcave umbilicus; test consists of a proloculus and an undivided tubular chamber. Coiling is planispiral evolute. The axis of coiling of the initial whorl may deviate with respect to the following planispirally coiled whorls. Wall is porcelaneous, imperforate, and very thick in later whorls. Comparison. This new genus is characterized by an extremely large size compared to other planispirally coiled foraminifers. The coiling of the proposed genus is quite similar to that of Crassispirella, Cornuspira, Ammodiscus, Pseudoammodiscus, Postcladella, and Forschia. But Megacrassispirella gen. nov. can be distinguished from Ammodiscus by its larger shell and porcelaneous wall. Cornuspira and Postcladella also have planispirally coiled whorls with a porcelaneous wall, but they are much smaller in size and have thinner walls compared with Megacrassispirella. The new genus Megacrassispirella is quite similar to Crassispirella in the style of coiling and wall structure. Although Gaillot & Vachard (2007) noted that Crassispirella produced one of the largest planispiral-evolute tests in the history of the Foraminifera, the tests of Megacrassispirella are two or three times larger than those of Crassispirella. In addition, Megacrassispirella has up to 14 whorls rather than 5–6 whorls in Crassispirella. Megacrassispirella also resembles Brunsispirella in wall structure and planispirally coiled whorls. But, Megacrassispirella is much larger and has a very strongly biconcave umbilicus. Megacrassispirella also resembles Forschia and Pseudoammodiscus in shape, but can be differentiated from the latter two genera by its porcelaneous wall.
Occurrence: Midian, Xainza area of central Tibet.
(Zhang et al. (2016)). [details]
From editor or global species database
Image from typetaxon