Hemigordiellina, Marie, 1961
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publication ID |
https://doi.org/ 10.26879/433 |
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publication LSID |
lsid:zoobank.org:pub:76D74301-4F2F-4A01-ADE5-EF52F8B53659 |
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persistent identifier |
https://treatment.plazi.org/id/03F9582F-FD70-FFD4-FC02-FD3134ABFC3A |
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treatment provided by |
Felipe |
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scientific name |
Hemigordiellina |
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Hemigordiellina View in CoL ? aff. simplex
Figures 20.5-20.8, 20.10, 20.11 View FIGURE 20. 1-4 , 34.15, 34.18 View FIGURE 34. 1-5
v. 2013 b Hemigordiellina ? aff. simplex (Harlton) - Vachard, Krainer and Lucas, p. 348 (no illustration).
Description. Whorls involute. Lateral sides of spire flat to slightly inflated. Peripheral margin rounded. Chamber walls thin. Measurements: D = 0.16 mm; h = 0.03-0.05 (rarely 0.07) mm; s = 0.01 mm.
Occurrence. Middle?-late? Kungurian (late Leonardian) of New Mexico (San Andres Fm: samples MLY(2) 4-2 and SAR 18-2).
Hemigordiellina ? aff. pseudopusilla (Baryshnikov in Zolotova and Baryshnikov, 1980)
Figure 33.23-33.24 View FIGURE 33. 1-14, 16, 18
? 1980 Glomospira? pseudopusilla Baryshnikov in Zolotova and Baryshnikov, p. 76-77, pl. 1, figs. 1, 2.
? 1986 Glomospira? pseudopusilla Baryshnikov ; Gorsky and Kalmykova, pl. 20, fig. 19.
v. 2013b Hemigordiellina ? aff. pseudopusilla (Baryshnikov in Zolotova and Baryshnikov) - Vachard, Krainer and Lucas, p. 348 (no illustration).
Description. Whorls involute. Lateral sides inflated. Peripheral margin rounded. No umbilicus. No sutures. Chamber walls thin. Measurements: D = 0.30-0.40 mm; whorls: 5; p = 0.02-0.05 mm; h = 0.05-0.06 mm; s = 0.02-0.03 mm.
Remarks. The generic assignment of this taxon is questionable. It appears transitional between the entirely glomospiral Hemigordiellina , and Hoyenella which exhibits a second planispiral stage. Moreover, Hoyenella itself is a questionable genus. It was described with a porcelaneous wall, but this character is not really demonstrated; and, if it is porcelaneous, Hoyenella appears very similar to several porcelaneous genera: Brunsiella Reitlinger, 1950 ; some Hemigordius Schubert, 1908 and Brunsispirella Vachard et al., 2005 . Similarly, if its wall is dark-walled microgranular, it might be a synonym of the Fusulinata Brunsia Mikhailov, 1935 ; if agglutinated, it corresponds exactly to some taxa assigned to the agglutinated Textulariata Glomospirella Plummer, 1945 . In fact, the type species of Glomospirella differs a lot from these small forms because it is a very large foraminifer, which can therefore be a synonym of Palaeonubecularia (=? Minammodytes Henbest, 1963 ; =?“ Tolypammina ” auct.), but, differs totally from the small Brunsia , Brunsiella , and Hoyenella .
The type species of Glomospirella ( Glomospira umbilicata Cushman and Waters, 1927 ) is a very large taxon, with a diameter of up to 1.00 mm. Its age is Middle/Late Pennsylvanian. However, the other species described in Glomospirella are small to very small (because they measure generally 0.25-0.40 mm) with a second part of coiling markedly planispiral and evolute (consistent with the definition of Loeblich and Tappan, 1964, for example). Glomospirella sensu stricto is a particularly large genus with either: 1) a siliceously agglutinated test; or 2) a recrystallized porcelaneous test (similar to many taxa in the North American Pennsylvanian; e.g., Henbest, 1963; Vachard and Krainer, 2001a, 2001b); or, finally, 3) an agglutinated and porcelaneous test as in Pseudospira or Palaeonubecularia (and, in general, many false tolypamminid forms of the Pennsylvanian). Furthermore, Glomospirella sensu Loeblich and Tappan, 1964 non Plummer, 1945 has at least two homeomorphs: 1) the Fusulinata Brunsia ; and 2) the Miliolata Brunsiella and some Hemigordius sensu lato. Another homeomorph is Hoyenella sensu stricto (i.e., the Triassic representatives of “ Glomospirella ” of the authors), the range of which has been extended to the Permian by Gaillot and Vachard (2007). The Permian glomospirellids evidently have a porcelaneous wall, whereas the true microstructure of Triassic Hoyenella is not well established (porcelaneous, calcitic microgranular, aragonitic microgranular, or an uncharacteristic and unknown wall?).
Gu et al. (2007) used Glomospirella with a question mark, but did not explain why. Moreover, they compared for example G.? mamilla Gu, Feng and He, 2005 (G.?: with a question mark) to G. robusta Scherp, 1962 (G.: without a question mark); whereas G.? curva Gu, Feng and He, 2005 is probably a Postcladella Krainer and Vachard, 2011 .
Groves and Boardman (1999, p. 249) admitted a perfect homeomorphy of Brunsiella and Brunsia , as well as the same wall microstructure (i.e., dark-microgranular). Therefore, they require two successive derivations from the common ancestor Pseudoammodiscus ; i.e., the first one in the Early- Middle Mississippian (for Brunsia ), and the second one in the Middle Pennsylvanian-Early Permian (for Brunsiella ). A lineage Pseudoammodiscus- Brunsiella-Hemigordius is also suggested by Groves and Boardman (1999). With such reasoning, Hoyenella will be a third derivation, in the Triassic. Similarly, we can admit a lot of derivations from “ Pseudoammodiscus ” auctorum and/or “ Pseudoglomospira ” auctorum, giving all the successive forms of the Lower Palaeozoic (previously called “ Ammodiscus ”, “ Cornuspira ”, “ Rectocornuspira ”, and now Pseudoammodiscus , Pseudospira , Postcladella , etc.). As indicated by Tappan and Loeblich (1988), Pseudoammodiscus might give rise to all the Triassic order Involutinida , and subsequently all the modern Miliolata. Finally, the descendants of Pseudoammodiscus may appear too prolific and too diverse.
An alternative hypothesis was presented by Vachard et al. (2005), Gaillot and Vachard (2007) and Vachard et al. (2010), based on the particular aspect and exceptional preservation of the porcelaneous wall; i.e., amber-colored or tan-skin. This aspect is relatively common among the well-preserved Hemigordius (for example in the Early Permian microfacies from Iran illustrated by Alipour et al., 2013). We admit that Brunsiella is also porcelaneous and constitutes the ancestor of Hemigordius . The first specimens with a porcelaneous test are more difficult to characterise. Vachard et al. (2010) suggested that the first ones belong to the calcivertellids (e.g., Calcivertella , Ammovertella ), and cornuspirids (either planispiral evolute: Cornuspira ; or streptospiral: Hemigordiellina sensu Vachard and Beckary, 1991 ).
The status of Warnantella Conil and Lys in Conil et al., 1977, whose FAD is poorly known, is uncertain and it corresponds either to a Miliolata or a Fusulinata (for example, to “ Pseudoglomospira ” sensu lato, according to Reitlinger in Vdovenko et al., 1993, p. 55, plate 10, figures 8, 9). Apparently, all authors admit the porcelaneous nature of the calcivertellid wall ( Loeblich and Tappan, 1964, 1987; Gaillot and Vachard, 2007; Vachard et al., 2010); nevertheless, Pronina (1994, figure 1, p. 22) proposed a phylogenetic tree, where calcivertellids are related to pseudoammodiscids as well as Hemigordius and Hemigordiopsis Reichel, 1945 (two genera for which a porcelaneous wall is also unanimously admitted). Inversely, if we admit the repetitive derivations from Pseudoammodiscus , the same reasoning leads to thinking that the derivations previously occurred in the Lower Palaeozoic, from the Ammodiscus of the literature. Consequently, in terms of wall microstructure, these primitive homeomorphs are not Fusulinata, but are Textulariata. Inversely, the Lower Palaeozoic forms are already Fusulinata, so, all the first forms of foraminifers are recrystallized Fusulinata and not Textulariata. Consequently, the megaevolution of the foraminifers during the Palaeozoic remains poorly known, but the schemes of Tappan and Loeblich (1988) or Pronina (1994) cannot be applied, either because there are misinterpretations of the Palaeozoic genera, or because of the lack of knowledge of the wall microstructures, respectively.
Occurrence. Early?-middle? Kungurian (late Leonardian) of New Mexico (Yeso Group: sample MG(2) 10-2. San Andres Fm: samples MLY 5-24, MLY 5-25, MLY(2) 5-10).
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