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Globorotalia mayeri Cushman & Ellisor 1939 from: Bolli, H.M.Saunders, J.B. (1985): Oligocene to Holocene low latitude planktic foraminifers. In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262
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Species Globorotalia mayeri Cushman & Ellisor 1939



Alternative name:
Discussion / Comments:
Bolli & Saunders (1985):
This species of wide geographic distribution in both low and mid latitudes and of extended stratigraphic range is widely used as an index form because of the value of its extinction level in the late Middle Miocene. The question as to whether or not G. siakensis LeRoy, originally described from Sumatra, and G. mayeri from Louisiana, are synonyms, has come under discussion in recent years particularly since Blow (1969) described them as being different, based on refigured holotypes. To obtain a better understanding of the mayeri/ siakensis problem for this book, Bolli & Saunders (1982a) investigated and compared a large number of specimens from the zonal type localities of the Cipero and Lengua formations of Trinidad, West Indies, ranging from the Globigerina ciperoensis ciperoensis to the Globorotalia mayeri Zone, and from well Bodjonegoro I in Java (Bolli, 1966b), from the Globigerinatella insueta (bottom of hole) to the Globorotalia mayeri Zone. Furthermore, the holotype of G. mayeri, previously illustrated by the original authors and re illustrated in Blow (1969) was again carefully re drawn and is here reproduced (Fig. 26.31). The principal criteria for a distinction of G. mayeri from G. siakensis as given by Blow are the distinctly curved spiral intercameral sutures and less lobate equatorial periphery in G. mayeri compared with the more radial sutures and more strongly lobate periphery in G. siakensis. Examination and re illustration of the G. mayeri holotype shows that the sutures are much less curved than in Blow's (1969) illustration and closer to Cushman & Ellisor's original figure. The variability studies furthermore revealed that when curvature of intercameral sutures occurs it is usually only between the last two chambers with the last chamber having a drawn backward, sack like (sacculiferid) shape. Specimens with this feature may occur throughout most of the range of the taxon. Presentation of these mayeri/siakensis investigations including the figuring of variabilities from alI zones throughout the range became too voluminous for inclusion in full here. Results, conclusions and extensive illustrations therefore had to be published separately (Bolli & Saunders, 1982a). Their conclusion was 'that neither on morphologic nor on stratigraphic distribution criteria can a clear distinction between G. mayeri and G. siakensis be maintained' and that they fall within the variability of one species. Both taxa were published in 1939, G. mayeri has priority over G. siakensis because its publication month is March 1939, whereas G. siakensis, originally thought to have been undated within 1939, has now been found to carry a November date (Bolli & Saunders, 1982b). Contrary to the findings in low latitudes as discussed above and in more detail by Bolli & Saunders (1982a), some workers in higher latitudes, such as Cita er al. (1978) and Borsetti et al. (1979) believe that they are in a position to distinguish clearly a Globorotalia siakensis type, i.e. forms with more radially arranged spiral sutures, more open umbilicus and more distinctly lobate equatorial outline, and a G. mayeri type which, compared with G.siakensis, possesses more oblique to slightly curved sutures on the spiral side, a very narrow umbilical area and a less lobate equatorial outline. These workers also believe they have evidence that in their areas these two morphologically distinguishable forms have also distinctly different stratigraphic significance in that G. siakensis ranges from the Globigerina ciperoensis ciperoensis Zone to the Globorotalia menardii Zone, G. mayeri from the upper part of the Globorotalia fohsi lobata Zone to the top of the Globorotalia mayeri Zone. Extensive faunal populations from, for example, the Mediterranean sections should be directly compared with those from low latitude sections to arrive at a reliable evolution of the variabilities in different latitudes. Differing views on origin and evolutionary trends of G. mayeri have been expressed. From observations in low latitudes G. mayeri appears to have evolved from the G. opima s.l. stock within the Catapsydrax stainforthi Zone. G. mayeri continued unchanged parallel to the evolving fohsi lineage and even survived it for a short time after the extinction of G. fohsi robusta, the last subspecies in the fohsi lineage. Some workers studying higher latitude faunas, where G. fohsi peripheroronda is also present but where the later fohsi subspecies did not develop, believe they have evidence that instead of G. mayeri giving rise to G. fohsi peripheroronda, this subspecies is instead the ancestor of G. mayeri (Jenkins, 1960, 1966; Blow, 1969). These questions of origin and evolution are also discussed in Bolli & Saunders (1982a). They concluded that still more complete documentation is needed from higher latitudes, where G. mayeri is thought to have evolved from peripheroronda, before such an interpretation can be considered proved. For the differences between G. mayeri and G. opima opima reference is made to the taxonomic notes on G. opima opima. G. mayeri differs from G. kugleri s.s. in its larger size, fewer chambers (5-6 instead of 7-8) in the last whorl, in the less curved intercameral sutures on the spiral side, which results in more globular chambers, and in a higher arched aperture. In axial view the chambers are more symmetrical compared with G. kugleri G. mayeri differs frorn G.fohsi peripheroronda in possessing more distinctly radial intercameral sutures on the spiral side, in the chambers being more regularly inflated, which again clearly shows in axial view, and in the aperture being distinctly higher arched compared with the low slit in G.fohsi peripheroronda. In the Catapsydrax stainforthi Zone intermediate forms may occasionally make a clear distinction between G. mayeri and G. fohsi peripheroronda difficult. Compared with the 4- 4 1/2 chambered G. obesa, G. mayeri possesses 5-6 less globular chambers increasing less rapidly in size. Sutures in G. obesa are more deeply incised, resulting in a more lobate periphery in equatorial view. In Trinidad G. mayeri coils at random from its appearance in the Globigerina ciperoensis ciperoensis to the Globigerinatella insueta Zone, to become strongly predominantly sinistral from the Globorotalia fohsi peripheroronda Zone onwards until its extinction at the top of the Globorotalia mayeri Zone. In Bodjonegoro 1, Java (Bolli, 1966b), the change from random to sinistral coiling also sets in within the Globorotalia fohsi peripheroronda Zone but, in contrast to Trinidad, continues to fluctuate on several occasions from random to sinistral through the lower part of the Globorotalia .fohsi fohsi Zone, from where coiling remains exclusively sinistral until the extinction of the taxon.
Bolli (1957):
Globorotalia mayeri has a remarkably long range compared with other Oligocene and Miocene species and subspecies of the genus. A close relation to G. opima nana, new species, new subspecies, is likely and it is also possible that G. fohsi barisanensis Le Roy branches off from this form in the Catapsydrax dissimilis zone.
Srinivasan (1975):
Many records of Globorotalia mayeri in the literature (e.g., Bolli, 1957 ; Blow, 1959) are referable to G. siakensis Le Roy. Globorotalia mayeri is characterized by ovate chambers and tangential sutures on the spiral side while G. siakensis is characterized by globular chambers, radial sutures on the spiral side, distinctly lobate equatorial outline, and fairly high-arched aperture.
Systematics:

32
 Familia Globorotaliidae
  Genus Globorotalia
   Species Globorotalia mayeri
Synonym list:
Bolli & Saunders (1985):
1939 Globorotalia mayeri Cushman & Ellisor. - Cushman & Ellisor : p.11 pl.2, figs.4a-c
1939 Globorotalia siakensis Le Roy. - LeRoy : p.39 pl.3, figs.30-31
1985 Globorotalia mayeri Cushman & Ellisor. - Bolli & Saunders : p.204 fig. 26.31-43; 6,9,12
Bolli (1957):
1939 Globorotalia mayeri Cushman & Ellisor. - Cushman & Ellisor : p. 11 pl. 2, figs. 4a-4c
1940 Globorotalia cf. mayeri Cushman & Ellisor. - Palmer : p. 292 pl. 28, figs. 5a-c
1949 Globorotalia mayeri Cushman & Ellisor. - Bermudez : p. 286 pl. 22, figs. 24-26
1949 Globorotalia (Turborotalia) mayeri Cushman & Ellisor. - Cushman & Bermudez : p. 44 pl. 8, figs. 16-18
1957 Globorotalia mayeri Cushman & Ellisor. - Bolli : pl. 28, figs. 4a-c
Srinivasan (1975):
1939 Globorotalia mayeri Cushman & Ellisor. - Cushman & Ellisor : p.11 pl. 2; fig. 4
1975 Globorotalia mayeri Cushman & Ellisor. - Srinivasan : p.149 pl. 4; fig. 6-9
Was used in synonym list of:
References:

LeRoy,L.W.. (1939):
Some small foraminifera, Ostracoda and otoliths from the Neogene ("Miocene") of the Rokan-Tapanoeli area, central Sumatra . Natuurk. Tijdschr. Nederl.-lndie, Vol. 99(6) p. 215-296

Cushman,J.A. and Ellisor,A.C. (1939):
New species of foraminifers from the Oligocene and Miocene . Cushman Lab. Foraminiferal Res. Contrib. Vol. 15(1) p. 1-14

Palmer,D.K. (1940):
Foraminifera of the Upper Oligocene Cojimar formation of Cuba, Part 3 . Mem. Soc. Cubana Hist. Nat. Vol. 14(4) p. 277-304

Bermudez,P.J. (1949):
Tertiary smaller foraminifers of the Dominican Republic . Spec. Publ.Cushman Lab. Foraminiferal Res., Vol. 25 p. 1-322

Cushman,J.A. and Bermudez,P.J. (1949):
Some Cuban species of Globorotalia . Contributions from the Cushman Foundation for Foraminiferal Research Vol. 25 p. 26-44

Bolli,H.M. (1957):
Planktonic foraminifera from the Oligocene-Miocene Cipero and Lengua formations of Trinidad, B.W.I..
In: Studies in Foraminifery, Bulletin of the U.S. National Museum Vol. 215 Eds: Loeblich, A.R.Tappan, H.Beckmann, J.P.Bolli, H.M.Gallitelli, E.M.Troelsen, J.C. p. 97-123

Srinivasan,M.S. (1975):
Middle Miocene Planktonic Foraminifera from the Hut Bay Formation, Little Andaman Island, Bay of Bengal . Micropaleontology Vol. 21(2) p. 133-150

Bolli,H.M. and Saunders,J.B. (1985):
Oligocene to Holocene low latitude planktic foraminifers.
In: Plankton Stratigraphy Eds: Bolli, H.M.Saunders, J.B. p. 155-262

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