Catalog - Globigerina conglomerata

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.

Globigerina conglomerata

Citation: Globigerina conglomerata Schwager, 1866

Type specimens: P. 44031 (Lectotype); : Original holotype - TAF. VII. fig 113 of Schwager 1866.

T. sphaeralis, spira plus minusve perspicua, qua complures fere loculi finibus aequaliter cochleatis, pustulatis eminent. Loculi subplanae circuli secttiones, marginibus corrotundatis, ad intus versis. Apertura labiata formata per fissuras loculorum ultimi circuitus, profunde sita, circumdata planis decurrentibus loculorum, plus minusve notatis. Putamen crassum, fere non grandibus foraminibus [Schwager 1866]

Description of neotype. The large globose test consists of 10 chambers (including the proloculum) arranged in a low trochospire of about two whorls with four chambers in each whorl. The equatorial profile is sub-circular, with a weakly and broadly lobulate equatorial periphery. The axial profile is sub-elliptical, the dorsal side being weakly convex and the ventral side being also convex. The axial periphery is broadly and smoothly rounded. The chambers are appressed, not greatly inflated, but are moderately embracing; in dorsal view they are reniform, becoming much longer circumferentially than broader radially. The sutures are weakly depressed and initially not very distinct. The spiral suture is lobulate and the intercameral sutures are slightly curved to nearly radial, dorsally meeting the spiral suture nearly at right angles. The umbilicus is distinct, moderately broad, quadrate in outline and deep. The primary aperture is a low interiomarginal arch totally confined within the umbilicus. No apertural lip, rim or tooth is visible on the neotype. The apertural face is somewhat flattened; it directly faces the umbilicus and forms a distinct although rounded angle with the remainder of the chamber wall. The wall is coarsely and uniformly perforate. The surface of the test is rough and cancellate, furnished with strong short spines which are particularly well developed along the margins of the umbilicus. [Banner & Blow 1960]

Mittlerer Hauptdurchmesser 0·6 Millim [Schwager 1866]
Maximum diameter of neotype: 0.75 mm. [Banner & Blow 1960]

A. FROM SCHWAGER 1866:
Typische Form. Das Gehäuse im Ganzen kuglig, mit meist mehr oder weniger deutlich ausgesprochener Spiralseite, an der eine grössere oder geringere Zuhl der Kammern mit nicht selten ziemlich regelmässig spiral gestellten, blasenartig erhobenen Enden herausragt. Die Kammern haben die Form von meist ziemlich flachen Kugelsegmenten, deren Ränder zugerundet und etwas nach innen geschlagen sind. Die lappige Mündung wird durch die Spalten gebildet, welche die Kammern des letzten Umganges nach innen zu zwischen sich lassen. Sie liegt ziemlich tief, und ist von den mehr oder weniger deutlich markirten Abfallflächen der Kammern umgeben. Die Schale dicht doch nicht sehr grobporig, in letzterer Hinsicht jedoch etwas wechselnd.

Abänderungen. Wenn man von der, den Globigerinen überhaupt eigenthümlichen veränderlichkeit absieht, so ist die vorliegende Form in Allgemeinen sehr beständig und an ihrer Kugelform, verbunden mit der tief gelegenen, von den flachig und schief einfallenden Innenseiten der Kammern umgebenen Mündung, wohl zu erkennen.

Vorkommen. Gemein in den Thonen beider Horizonte von Kar Nikobar.

Verwandtschaft. Eine nicht ganz unbedeutende Ahnlichkeit scheint unsere Form mit der von Baylei (Microscopical forms in soundings made by the U. S. coast survey, in Smithsonian contribution to Knowledge vol. II, Abth. III, fig. 20-22) als Globgerina rubra d'Orb. abgebildete Form zu besitzen, doch wachsen bei letzierer die Kammern weit rascher an, wodurch die Form eine weniger kugelförmige Gestalt erhält. [Schwager 1866]

B. FROM BANNER & BLOW 1960
Taxonomic remarks. This species was first described by C. Schwager from the Neogene deposits of Kar Nikobar, British India. He published an illustration of the ventral view only, and never amplified the original description.
H. B. Brady received identified topotypic (metatypic) specimens from Schwager. It is not known whether these specimens were determined by Schwager before or after the date of his publication of the species; if it were the former case the specimens would be available as syntypes, but otherwise they rank only as metatypes. 40 specimens were present in the slide, marked "G. conglomerata ex Schwager Colin., Kar Nikobar,"" and Brady (1884, p. 596) on comparing the material sent by Schwager with Schwager's illustration (Schwager, 1866, pI. 7, fig. 113), remarked that "the author's figure is not a very satisfactory rendering of their distinctive characters." However, we consider that all the specimens were conspecific and agreed with the ventral view illustrated by Schwager.
Professor M. Reichel (Basel) has informed us (personal letter, dated 14th July, 1959) that to his knowledge the Schwager collections in Munich are lost. We ourselves have made further enquiries without success and following the Copenhagen Decisions on Zoological Nomenclature (Hemming, 1957, p. 28-32) we designate Schwager's metatypic specimen, here illustrated (pI. 2, fig. 3), as neotype of Globigerina conglomerata Schwager 1866. This specimen is deposited in the British Museum (Natural History), London, registered number P. 44031. [Banner & Blow 1960]

Remarks. The slide sent to Brady containing the metatypes is marked ""Pliocene"" although the age given by Schwager in his publication is merely ""Younger Tertiary."" We ourselves have observed this species in the Pliocene of Sicily and it probably ranges from this age to the Recent.
A number of other large globose globigerines with four chambers in the final whorl exist in Upper Eocene to Miocene deposits and these all seem to be very closely related to Schwager's species. The distinctions between these forms are very subtle although stratigraphically valuable. It seems highly likely that Globigerina venezuelana Hedberg 1937 and Globigerina rotundata var. jacksonensis Bandy 1949 should be considered as subspecies of G. conglomerata Schwager. However much more work on the morphology of these other forms is required before their relationships can be fully evaluated.
We have seen the holotype of Globigerina bulloides var. quadripartita Koch 1926 which was kindly lent to us by Dr. E. Gasche of the Naturhistorisches Museum, Basel, Switzerland; unfortunately, as the holotype of Koch's species is broken and its ventral side is largely destroyed, its specific characters cannot be ascertained. We will be discussing this species at greater length in a further publication but it seems best to consider this taxon as nomen dubium.
We believe that G. conglomerata Schwager is distinguishable from G. dutertrei d'Orbigny and is a recognisably distinct species of the genus Globigerina d'Orbigny. [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 O

Schwager, C. (1866). Fossile Foraminiferen von Kar Nikobar, Reise der Oesterreichischen Fregatte Novara um Erde in den Jahren 1857, 1858, 1859 unten den Befehlen des Commodore B. Von Wuellerstorf-Urbair. Geologischer Theil, Geologische Beobachtung no. 2, Palaeontologische Mittheilung. 2: 187-268. gs O

Terquem, O. (1882). Les foraminiferes de l’Eocene des environs de Paris. Mémoires de la Société Géologique de France. 2(3): 1-193. gs O

CATALOG OF ORIGINAL DESCRIPTIONS: Globigerina conglomerata Schwager, 1866

Globigerina conglomerata

References:

Add Comment

Comments