Taxon Concept provided by
  Home |   Search

Click on a letter below to get a list of species:
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z all
Globorotalia (Turborotalia) bauerensis Quilty 1976 from: Quilty, P.G.. (1976): Planctonic foraminifera DSDP Leg 34- Nazca Plata . DSDP initial reports Vol. 34
.
Anonymous: Unedited TaxonConcept data
Notice: This catalogue page may contain unedited data.

Species Globorotalia (Turborotalia) bauerensis Quilty 1976


Alternative name:
Diagnosis / Definition:
Quilty (1976):
Diagnosis: Distinguished by the lack of an umbilicus and the presence of a narrow, slightly concave distal portion of the ventral surface of each chamber, parallel to the periphery. Description: Test small (0.13 mm), smooth. Four chambers in the final whorl. Chambers markedly longer tangentially than radially. Dorsal surface a low convex dome, central details obscured by overgrowth. Intercameral sutures of the final whorl, broadly and shallowly depressed, chamber contact well marked; quite markedly recurved distally. Periphery lobulate; angled but not keeled. Ventral surface a low dome. Intercameral sutures a little recurved distally, broadly and shallowly depressed, chamber contact distinct. Surface of first chamber (perhaps second also) of final whorl finely pustulose but whether naturally or by overgrowth is not clear. Umbilicus absent. Aperture a low arch from the proximal part of the last chamber to the periphery; bordered by a small distinct lip best developed distally. Wall thin. Distal part of ventral surface of all chambers slightly depressed near periphery.
Discussion / Comments:
Quilty (1976):
Remarks: Three species must be discussed here. They are G. (T.) anfracta Parker, G. akersi n. sp., and G. bauerensis n. sp. They are closely related. G. akersi and G. bauerensis have in common tangentially elongate chambers, markedly different from G. anfracta. G. akersi has the aperture completely extrambilical. G. bauerensis has a slight concavity parallel to the periphery on the distal edge of the ventral surface of each chamber. G. anfracta has a rounded periphery whereas G. akersi and G. bauerensis have angled but not keeled margins. G. anfracta has a wide, well-developed apertural flap. In both new forms the apertural flap is small and of varying width. The stratigraphic distribution of these forms suggests an evolutionary sequence from G. baurensis (middle Miocene, N9-N12) through G. akersi (middle Miocene, NI2) to G. anfracta (late Miocene- Pliocene, NI8/19 in this area). This evolution involves movement in time of the aperture from the peripheral to extraumbilical position, general lessening of the angularity of the periphery and decrease in the relative tangential length of the chambers. Origin of name: The Bauer Deep in which Site 319 was drilled.
Synonym list:
Quilty (1976):
1976 Globorotalia (Turborotalia) n sp. bauerensis Quilty. - Quilty : p.693 pl. 14, figs. 14-15
References:

Quilty,P.G.. (1976):
Planctonic foraminifera DSDP Leg 34- Nazca Plata . DSDP initial reports Vol. 34
Anonymous: Unedited TaxonConcept data
Creative Commons Attribution 2.5 License
This work is licensed under a Creative Commons Attribution 2.5 License.