Catalog entries: Prunopyle titan
Original description: Shell generally ovate, large, with distinct osculum; egg-shaped shell stoutly proportioned (1.5-1.6 times its maximum diameter in length), with evenly contoured walls which round off at unmodified apical end and which end antapically at extended osculum; osculum subtubular, very short (less that, 0.1 total length in length and 0.2 greatest diameter in diameter), with about 16 projecting, slightly incurved spines around its margin and acting as stays; wall fairly thick; surface smooth; pores of shell very closely set, small (less than 4.4µm), circular, at inner ends of tubules connecting with surface, tubules mostly directed apically, pores on osculum similar but set farther apart, and not deep-set.
Length, 280µm, of tubular osculum, 40µm. Distinguishing characters (rw): Prunopyle titan n. sp. differs from Eocene species occidentalis (1942) in shape and in prominence and character of osculum. Two species not closely related, and neither has an inner concentric medullary shell.
Presence of several different sizes of individuals among specimens examined in this Miocene material suggests strong influence of temperature upon shell formation. As with other pelagic protozoans, notably loricate ciliates, this accounts for presence of many dwarfed individuals among species otherwise large in size. These small individuals are thus probably not result of unusual water conditions or other adverse factors in environment but rather follow perhaps normal temperature changes in medium. That these small individuals are younger than larger individuals is hardly possible as these shells appear to lack intussusceptional growth. Both large and small individuals occur side by side but may have been formed at different times.
Similar species: titan
Last occurrence (top): within Neogene Period (2.59-23.03Ma, top in Piacenzian stage). Data source: Lazarus et al. 2015 - "N age group"
First occurrence (base): within Neogene Period (2.59-23.03Ma, base in Aquitanian stage). Data source: Lazarus et al. 2015 - "N age group"
Plot of occurrence data:
Larcopyle titan compiled by the radiolaria@mikrotax project team viewed: 27-11-2020
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