Tholospyris baconiana variabilis


Classification: rads_cenozoic -> Trissocyclidae -> Triospyridae -> Tholospyris -> Tholospyris baconiana -> Tholospyris baconiana variabilis
Sister taxa: T. baconiana baconiana, T. baconiana variabilis

Taxonomy

Citation: Tholospyris baconiana variabilis Goll 1973
Rank: sub-species
Basionym: Tholospyris baconiana variabilis

Catalog entries: Tholospyris baconiana variabilis

Original description: A subspecies of Tholospyris baconiana characterized by tribladed lattice bars on the back of the basal ring and tribladed lattice bars surrounding four pairs of large, sagittal lattice pores.Sagittal ring subpolygonal, 50 to 67 microns high, 42 to 47 microns thick, joined directly to front and back of lattice shell. No apical or axial spines; vertical spine very short, arising near base of sagittal ring. Single slender connector bar projecting vertically from front-apex of sagittal ring. On complete specimens, a single short connector bar projecting from front-base of sagittal ring. On specimens with lower portion of lattice shell incomplete, a short frontal spine projecting at this position. Primary lateral bars joined to basal ring no other basal connector bars.
Basal ring subpolygonal, tribladed on sides and back exterior surface, indented laterally and sagittally, 65 to 72 microns wide, 47 to 62 microns thick, joined directly to front and back of sagittal ring. encloses four basal pores. Lattice bars joined to basal ring irregular in number and position. Lattice shell 87 to 172 microns high. 90 to 127 microns wide. completely enclosed, surrounds apex and base of sagittal ring. Slight horizontal constriction at base of sagittal ring. Distal horizontal constriction at base of sagittal ring. Distal portions of lattice shell uniformly composed of thin. smooth, lattice bars separating small, densely-spaced, subcircular, lattice pores. Four broad lattice bars joined to front-middle, front-apex, back-apex and back-middle of sagittal ring. Four pairs of large, sagittal lattice pores surrounded by tribladed lattice bars and covered by thin, perforate, lattice plates. No lattice shell tubercles or lattice spines. No front, vertical or sternal pores. Distinguishing characters (rw): Representatives of Tholospyris baconiana variabilis, n. subsp., differ from those of other subspecies of T. baconiana in having tribladed lattice bars and no lattice spines. Tholospyris variabilis most closely resembles Tricolospyris leibnitziana Haeckel, 1887, but is distinguished from the latter by the absence of tribladed lattice bars on the lateral portions of the lattice shell. Tholospyris baconiana variabilis differs from the type species of Tholospyris, T. cortinisca, by the absence of an apical lattice spine. Phylogeny (rw): Tholospyris baconiana variabilis is the intermediate in the cladogenesis resulting in T b. spinula, n. subsp. Moreover, it forms the base in an anagenetic trend which has Tholospyris devexa devexa (Haeckel) and Tholospyris devexa finalis, n. subsp., as its extant representatives.

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within (-Ma, top in "Holocene" stage). Data source:
First occurrence (base): within (-Ma, base in stage). Data source:

Plot of occurrence data:

References:


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Tholospyris baconiana variabilis compiled by the radiolaria@mikrotax project team viewed: 25-11-2020

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