|Daughter taxa: (blue => in age window 0-800Ma)||Granddaughter taxa|
|Extant and Pliocene species|
Small to medium sized. Flange narrow without distinct wing. Central-area with two small in-line pores.
Like H. carteri but coccoliths with closed central area (i.e. no pores) and usually smaller; also blanket is confined to central area leaving a broader rim of exposed flange elements than in H. carteri.
Medium to large size, flange ends in wing, two inline pores in central-area.
Like H. carteri but central-area with inclined pores.
Like H. carteri but with single long slit in central area
Like H. carteri but with large pores separated by prominent conjunct sub-horizontal bar usually with inverse orientation.
Like H. carteri but pores large. (Late Pliocene- Early Pleistocene)
|Oligocene - Early Miocene species with conjunct bar|
Like H.carteri but older (NP23-24) - also slits in central area and wing less developed.
two large pores in central area and flange truncated.
Like H. carteri but with large pores
Small species (2.5-4.5 µm) with slit in the central area.
|Oligo-Miocene species with disjunct bar|
Bar thin straight and inclined
Bar broad straight and strongly inclined, almost fills central area
Bar broad straight and strongly inclined, fills central area
bar sigmoid, nearly horizontal
Like H. carteri but very large, central-area open, spanned by horizontal disjunct bar.
Distinguishing features: Living and Neogene medium to large species (typically 7-11 microns) with flanges that end in distinct wings.
Farinacci & Howe catalog pages:
Morphology: These are medium to large species (typically 7-11 microns) with flanges that end in distinct wings. They are the most common helicoliths in most samples, but vary markedly through the Neogene. Forms with disjunct (optically discontinuous) bars (H. euphratis & H. intermedia) dominate in the Early Miocene but are replaced progressively by forms with closed central areas or conjunct bars. The blankets on these are initially rather chaotic (H. granulata) but forms with well ordered blankets with two in-line pores (H. carteri) become more common through the Late Miocene. In the Pliocene, forms with large and/or oblique pores (H. sellii and H. wallichii) become common.
Size: Predominantly medim to large species (coccoliths 8-12 µm), the main excpetions being modern H. pavimentum (coccoliths 4-6 µm) and H. hyalina (coccoliths 5-8 µm). At least on modern H. carteri coccosphere size increase predominantly occurs by incresing the number of coccoliths/langth of th coccosphere rather than by incresing the size of the coccoliths or diameter of the coccoosphere.
Phylogenetic relations: H. hyalina and H. wallichii have often been regarded as varieties of H. carteri (e.g. Jordan & Young 1990, Jordan & Green 1994, Cros & Fortuño 2002), since they are similar in size and coccospheres bearing more than one morphotype have been illustrated (e.g. Nishida 1979). However cultures observations and molecular genetic data indicates that they are distinct species (Sáez et al. 2003, Geisen et al. 2004).
|Metrics||Lith size: 4->12µm; Coccosphere size: 9->25µm;|
Last occurrence (top): Extant Data source: Total of range of species in this database
First occurrence (base): near base of Priabonian Stage (11% up, 37.3Ma, in Priabonian stage). Data source: Total of range of species in this database
Plot of occurrence data:
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