Globigerinoides italicus


Classification: pf_cenozoic -> Globigerinidae -> Globigerinoides -> Globigerinoides italicus
Sister taxa: G. elongatus, G. extremus, G. conglobatus, G. eoconglobatus, G. obliquus, G. altiaperturus, G. joli, G. neoparawoodi, G. kennetti, G. bollii, G. italicus, G. ruber, G. mitra, G. seigliei, G. subquadratus, G. diminutus, G. bulloideus, G. sp.,

Taxonomy

Citation: Globigerinoides italicus Mosna and Vercesi, 1975
Rank: species
Synonyms:
Taxonomic discussion:

The species Globigerinoides parawoodi was established by Keller (1981) to include specimens of Globigerinoides that she thought derived from Globoturborotalita woodi. However, the holotype of G. parawoodi does not show direct lineage affinity with G. woodi (Plate 9.3, Figs. 8, 12, 16, this chapter). On the contrary, the holotype of G. parawoodi strongly resembles in outline and wall texture Globigerinoides italicus Mosna and Vercesi 1975 (even if the wall of G. italicus is more heavily calcified and recrystallized). Globigerinoides parawoodi Keller is here placed in synonymy with G. italicus by comparing the holotypes of the two species (Plate 9.3). Although Globigerinoides parawoodi Keller has been the more commonly used name, G. italicus has been also cited by Brambilla and others (1983); and in the geological map of Italy N. 369 (Centamore and others, 2006). Therefore, we have synonymized the two species and retained the name G. italicus as the senior synonym.

Confusingly the so-called “holotype” of G. parawoodi documented by Keller (1981, pl. 4, figs. 6-8) is composed of two specimens, the image of the spiral side (pl. 4, fig. 6) shows a sinistrally coiled specimen, whereas the image of the umbilical side shows a dextrally coiled specimen (pl. 4, fig. 8). In addition neither of the two documented images corresponds to the holotype deposited at the Smithsonian Museum of Natural History, Washington, D.C. with the reference number 307083 (Plate 9.3, Figs. 8, 12, 16). [Spezzaferri et al. 2018]

Catalog entries: Globigerinoides italicus, Globigerinoides parawoodi

Type images:

Distinguishing features: Primary aperture, an inverse drop-like and elongated arch, higher than it is wider

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
They are being edited as the site is developed and comments on them are especially welcome.

Description


Diagnostic characters:

Globigerinoides italicus is distinguished from all other species of Globigerinoides by the size, shape and position of the primary aperture, an inverse drop-like and elongated arch, higher than it is wider. It differs from G. bollii by the shape and position of the primary aperture and the slightly more lobate outline. It differs from G. subquadratus by having 3½ to 4 chambers in the last whorl instead of 3 and its narrower primary aperture. [Spezzaferri et al. 2018]


Wall type: Normal perforate, spinose, ruber/sacculifer-type wall.

Test morphology: Low trochospiral, consisting of about 2½-3 whorls, subtriangular, rather compact and massive, slightly lobate in outline, chambers globular; 3½-4 subspherical chambers in the last whorl, increasing slowly in size. Sutures slightly depressed, straight to slightly curved on both sides, umbilicus small. Primary aperture umbilical, an elongated arch, higher than it is wide, tending to become oblique and to move laterally, in several specimens it is narrow at the base and more enlarged towards its upper part, resembling a reversed drop, bordered by a thin rim. A small supplementary aperture is placed over the sutures separating the last and the penultimate chamber, an additional very small aperture may be seen in some specimens and is placed over the sutures between the penultimate and antepenultimate chambers. [Spezzaferri et al. 2018]

Size: Maximum diameter of holotype about 0.40 mm. [Spezzaferri et al. 2018]

Character matrix

test outline:Ovatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Low-moderateperiphery:N/Aaperture border:N/A
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:Sutural
spiral sutures:Strongly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:3.5-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Low to middle latitudes, including the Pacific Ocean and Mediterranean Sea. [Spezzaferri et al. 2018]

Isotope paleobiology: No data available. [Spezzaferri et al. 2018]

Phylogenetic relations: Globigerinoides italicus probably evolved from G. neoparawoodi n. sp. at the top of Subzone M1a. [Spezzaferri et al. 2018]

Most likely ancestor: Globigerinoides neoparawoodi - at confidence level 2 (out of 5). Data source: Spezzaferri et al. 2018.
Likely descendants: Globigerinoides bollii; Globigerinoides subquadratus;

Biostratigraphic distribution

Geological Range:
Notes: This species was described from the lower Pliocene of western Liguria, Italy; however, due to the synonymy of G. parawoodi Keller with G. italicus, its range should be extended to the top of Subzone M1a in the lower Miocene within the range distribution of P. kugleri. [Spezzaferri et al. 2018]
Last occurrence (top): within Early Pliocene Sub-Epoch (3.60-5.33Ma, top in Zanclean stage). Data source:
First occurrence (base): within M1a subzone (22.44-22.96Ma, base in Aquitanian stage). Data source:

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.9 p.278

References:

Brambilla, G., Cantaluppi, G. & Lualdi, A. (1983). Panorama generale del Pliocene nel bergamasco. Rivista Museo Scienze Naturali di Bergamo. 6: 3-25. gs

Centamore, E., Crescenti, U. & Dramis, F. (2006). . Note Illustrative della carta geologica d’Italia alla scala 1: 50.000, Foglio 369 Servizio Geologico d’Italia. 369: 1-159. gs

Keller, G. (1981). Origin and evolution of the genus Globigerinoides in the Early Miocene of the northwestern Pacific, DSDP Site 292. Micropaleontology. 27(3): 293-304. gs

Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs

Mosna, S. & Vercesi, P. L. (1975). Globigerinoides italicus nuova specie del Pliocene inferiore ligure. Atti dell’Istituto geologico dell’ Universita di Pavia, Pavia. 25: 14-15. gs

Spezzaferri, S. (1994). Planktonic foraminiferal biostratigraphy and taxonomy of the Oligocene and lower Miocene in the oceanic record. An overview. Palaeontographia Italica. 81: 1-187. gs

Spezzaferri, S., Olsson, R. K. & Hemleben, C. (2018b). Taxonomy, biostratigraphy, and phylogeny of Oligocene to Lower Miocene Globigerinoides and Trilobatus. In, Wade, B. S. , Olsson, R. K. , Pearson, P. N. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 46(Chap 9): 269-306. gs


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Globigerinoides italicus compiled by the pforams@mikrotax project team viewed: 14-11-2019

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