CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina megastoma Earland 1934

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 -> G -> Globigerina -> Globigerina megastoma
Other pages this level: << < G. konkensis, G. kozlowskii, G. krosniensis, G. kugleri, G. kyushuensis, G. labiacrassata, G. linaperta, G. linaperta transdanubica, G. linaperta turgida, G. loetterli, G. lozanoi, G. macrastoma, G. marialuisae, G. mckannai, G. medizzai, G. megastoma, G. megastoma cariacoensis, G. mexicana, G. microfoliata, G. micropora, G. microstoma, G. microstoma opsionepenthoides, G. minutula, G. moskvini, G. multiloba, G. nepenthes, G. nepenthes delicatula, G. nepenthoides, G. nilotica, G. nipponica, G. nitida, > >>

Globigerina megastoma

Citation: Globigerina megastoma Earland 1934
Rank: species
Type locality: Discovery" Station 385 (Drake Straits) from 3638 metres depth
Type age: Recent
Holotype Repository: London, UK; NHM
Type & figured specimens: ZF.3279 - syntypes; 1959.5.11.740 - lectotype designated by Banner & Blow 1960

Linked specimens: London, UK; NHM (1959.5.11.740)

Current identification/main database link: Beella megastoma (Earland 1934)


Original Description

Description of lectotype.-The fairly large test is composed of about . eleven chambers arranged in about 2Yz whorls comprising a high and loosely coiled trochospire. There are four rapidly and uniformly enlarging, inflated chambers in each whorl. The equatorial profile is sub-circular and the test has a very strongly lobulate equatorial periphery. The axial profile is sub-conical with a smoothly lobulate axial periphery. The chambers are sub-globular, well separated, and only slightly embracing. The last chamber especially shows slight elongation in a direction oblique to the axis of coiling. All the sutures are strongly depressed and deeply and broadly incised. The umbilicus is moderately broad and very deep and the relict parts of the earlier primary apertures are clearly visible within it. The primary aperture of the last chamber is interiomarginal, umbilical, extending the full width of the umbilicus, but it is only half as high as the smoothly convex apertural face. The aperture possesses a well developed, apparently perforate, symmetrical lip along its length. The wall is thin, uniformly and finely perforate. The surface is smooth and the test often appears translucent. [Banner & Blow 1960]


Size: Maximum diameter of lectotype: 0.63 mm. [Banner & Blow 1960]

Extra details from original publication

Taxonomic remarks: In addition to very many small specimens of this species present in the Heron-Allen and Earland collections in the British Museum (Natural History), London, the four syntypes which were illustrated by Earland are also preserved. The four illustrated syntypes came from "Discovery"" Station 385 (Drake Straits) from 3638 metres depth and were preserved on a slide registered as ZF.3279 in the British Museum (Natural History). The lectotype, here designated and illustrated (pI. 1, fig. 3), was removed from this slide and is now registered as number 1959.5.11.740 in the British Museum (Natural History) records. [Banner & Blow 1960]

Remarks: Earland's specimens varied considerably in size and the lectotype was chosen from the four largest specimens present in the collection which was illustrated by Earland (loc. cit.). Earland's illustrations tend to make the species appear far more hispid and coarsely perforate than is actually the case. Smaller and probably immature specimens tend to show the oblique elongation of the chambers more noticeably, and the form illustrated by Be (1959, pI. 1, figs. 15-17) is very similar to those in the Earland collection. We are of the opinion that Be's Globigerina bulloides (op. cit., loco cit.) is in fact Globigerina megastoma. However, the possibility also exists that the model no. 17 (""young form"") of Globigerina bulloides issued in 1823 by d'Orbigny may also be referable to this species.
G. megastoma, although congeneric with G. bulloides, differs from the latter by possessing a very thin wall, a smaller umbilicus, a higher spire, more elongate and better separated chambers and an exceedingly well developed apertural lip.
This species has only been seen by us in collections from the recent seas and we have not observed it fossil. [Banner & Blow 1960]"

References:

Banner, F. T. & Blow, W. H. (1960a). Some primary types of species belonging to the superfamily Globigerinaceae. Contributions from the Cushman Foundation for Foraminiferal Research. 11: 1-41. gs V O

Earland, A. (1934). Foraminifera. Part III. The Falklands sector of the Antarctic (excluding South Georgia). Discovery Reports. 10: 1-208. gs


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Globigerina megastoma compiled by the pforams@mikrotax project team viewed: 19-9-2020

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