Podocyrtis helenae


Classification: rads_cenozoic -> Pterocorythidae -> Podocyrtis -> Podocyrtis helenae
Sister taxa: P. acalles, P. ampla, P. apeza, P. aphorma, P. argulus, P. chalara, P. coronatus, P. diamesa, P. dorus, P. fasciolata, P. goetheana, P. helenae, P. mitra, P. mitrella, P. papalis, P. phyxis, P. platypus, P. sinuosa, P. trachodes, P. sp.

Taxonomy

Citation: Podocyrtis helenae Nigrini 1974
Rank: species
Basionym: Podocyrtis helenae
Taxonomic discussion: Nigrini 1974 No: Podocyrtis (Lampterium) helenae Nigrini

Catalog entries: Podocyrtis helenae

Original description: Shell smooth, quite thick-walled. Cephalis [three-lobed], subspherical with many subcircular pores and thorn-like 3-bladed apical horn. Thorax campanulate with subcircular pores either aligned longitudinally (5 to 7 in a row) or irregularly arranged, seven to nine on a half-equator. Lumbar stricture distinct. Abdomen elongate, expanded distally with subcircular pores sometimes aligned longitudinally (8 to 13 in a row) but often irregular, 8 to 12 on a half-equator. Ridges between the longitudinal rows may become sinuous to follow irregularities in pore arrangement. Peristome rather wide, smooth, poreless with three spathulate feet.

Based on 20 specimens. Length of thorax 50-65 µ; of abdomen (including peristome and feet) 133-248 µ. Breadth of thorax 83-100 µ; of abdomen 115-150 µ. Distinguishing characters (rw): P. (L.) helenae is distinguished from P. (L.) sinuosa and P. (L.) mitra by the abdominal pores being smaller and less regularly arranged, and the abdominal wall being generally thinner. (Sanfilippo et al., 1985) Phylogeny (rw): This species is apparently an evolutionary offshoot from P. (L.) sinuosa, and left no descendants.
Remarks on original description: The smooth shell resembles that of P. (L.) mitra in its general truncate-conical form, and varies from thick-walled to (more usually) quite delicate. Abdominal pores are sometimes aligned longitudinally but are more often irregularly arranged and unevenly distributed. Ridges between the longitudinal rows in some specimens become sinuous because of the irregularities in pore arrangement. (Sanfilippo et al., 1985)

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within Paleogene Period (23.03-66.04Ma, top in Chattian stage). Data source: Lazarus et al. 2015 - "P age group"
First occurrence (base): within Paleogene Period (23.03-66.04Ma, base in Danian stage). Data source: Lazarus et al. 2015 - "P age group"

Plot of occurrence data:

References:

Nigrini, C. A. (1974). Cenozoic Radiolaria from the Arabian Sea, DSDP Leg 23. Initial Reports of the Deep Sea Drilling Project. 26: 1051-1121. gs


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Podocyrtis helenae compiled by the radiolaria@mikrotax project team viewed: 28-10-2020

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