CATALOG OF ORIGINAL DESCRIPTIONS: Eoglobigerina fodina Blow 1979

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: pf_cat -> E -> Eoglobigerina -> Eoglobigerina fodina
Other pages this level: E. appressa, E. edita praeedita, E. eobulloides simplicissima, E. extensa, E. ferreri, E. fodina, E. maamouri, E. operta

Eoglobigerina fodina

Citation: Eoglobigerina fodina Blow 1979
Rank: species
Type locality: DSDP Site 47/2, sample 11/5, 148-150 cm, cored at a depth of 2689 meters on the Shatsky Rise, lat. 320 26.9' N. , long. 1570 42.7' E., northwestern Pacific Ocean.
Type age (chronostrat): Basal Paleocene, lowermost Danian, zone P.a (Globorotalia (Turborotalia) longiapertura partial-range zone).
Type specimens: PM PF 63586
Type repository: London, UK; NHM

Linked specimens: London, UK; NHM (PM PF 63586)

Current identification/main database link: Parvularugoglobigerina extensa (Blow 1979)


Original Description
The extremely small test is coiled in a fairly low but tightly expressed trochospire with about 10 chambers comprising the spire and with four chambers in the last whorl. In dorsal aspect, the chambers are inflated, subglobular, somewhat appressed and slightly embracing; the dorsal intercameral sutures are depressed to incised and subradially to radially disposed. In ventral aspect, the chambers are inflated, somewhat embracing but not closely appressed. The umbilicus is small but open whilst the aperture is a circular opening extending from the umbilicus, in a slightly oblique manner, into the terminal face of the last chamber. Since the aperture is open to the umbilicus for a small part of the base of the last chamber, it must be considered interiomarginal in position notwithstanding its circular shape. The aperture is bordered by a rim-like margin which, from fig. 6, appears to be portical in character. The wall texture is extremely finely perforate with very widely and sparsely developed mural pores which do not open into pore-pits. The wall bears small pustules which may be the bases of normal spines.

Size: Maximum diameter of holotype 0.098 mm as measured electronically.

Extra details from original publication
The occurrence of this taxon is not as rare as the lack of illustration of paratypes would suggest. However, difficulties of handling such a small form account for the absence of additional illustrations. Since the wall is extremely thin and fragiie, the taxon is often broken during handling. Nevertheless, all morphotypes seen have a very constantly expressed and stable morphology so that the single illustration of the holotype is adequate to characterise the taxon. The apertural system is extremely peculiar and does not match the nature of the apertural systems of any other form included in either the genus Eoglobigerina or Globastica Blow, 1979. In the discussion given for Eoglobigerina? extensa Blow, 1979, reference is made to the characters of the wall texture of both fodina and extensa in relationship to the normally seen wall textures of [other] Eoglobigerina spp. and Globastica spp. Thus, like the case discussed for extensa, (see catalogue sheet) the writer doubts if the assignation offodina to the genus Eoglobigerina Morozova, emend. Blow, 1979, will be maintained following future work on these stratigraphically very early Cainozoic globigerinacean morphotypes. It is likely that both fodina and extensa are more closely related to Giobastica daubjergensis (Brönnimann) [Globigerina daubjergensis, 1953] on the characters of the wall texture and/ or structure than to any presently known other taxon included in the genus Eoglobigerina. However, as noted for exrensa, the writer considers it best to place Iodina in Eoglobigerina for the time being at least so as to clearly delimit the characters of the genus Globastica as well as to take note that the apertural characters of bothfodina and extensa are not strictly similar to those of the type-species of Globastica, i.e., Globigerina daubjergensis Brönnimann, 1953.

References:

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs


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Eoglobigerina fodina compiled by the pforams@mikrotax project team viewed: 28-10-2020

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Comments (1)

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François

Hello,

Eoglobigerina fodina Blow 1979 is the type species of Palaeoglobigerina Arenillas, Arz & Náñez, 2007. Is the synonymy with Parvularugoglobigerina extensa (Blow 1979) still valid?

Thank you,

François

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Jeremy Young (UK)

I'm afraid that is subjective. The taxonomy of Arenillas et al. 2007 is, as I understand it, not universally accepted.

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