Catalog - Hantkenina multispinata

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Hantkenina multispinata

Citation: Hantkenina multispinata Cushman&Wickenden 1930

Type specimens: USNM paratype CC13144; Plate 6, figures 4-6

Type locality: NB. 1/4, sec. 11, T. 6 N.; R. 8 W. of principal Meridian on North bank of Boyne River, southern Manitoba, Canada.

Type repository: Washington; USNM

Test planispiral in general, the adult chambers sometimes slightly out of alignment, earlier chambers globular but very early developing a distal tubular extension, in general in a radial position, later chambers polyhedral and with as many as five tubular processes, three chambers making up each coil; suture fairly distinct, slightly depressed; wall smooth, calcareous, thick, finely perforated; aperture a low arched opening at the base of the chamber, in the earlier stages in the median line but in the adult extending outward to the umbilical area at least on one side, with a thin lip over the opening.

Length of adult about 0.24 mm.; thickness at umbilicus 0.09 mm.; at periphery of last chamber 0.18 mm.

With the help of the figures definite stages may be made out:
Nepionic:-Proloculum globular, nearly or quite spherical followed by at least two chambers of a similar form and nearly equal size.
Neanic:- the next succeeding chamber becoming elongate in a radial direction, bluntly pointed but apparently without a definite, tubular process, succeeding chambers carrying this structure to a constantly higher degree until the chamber is longer than broad, constricted toward the proximal end and expanded in the middle, thence tapering distally into a comparatively large tubular extension.
Ephebic:-The form keeps to the general planispiral development, but the chambers become much expanded, greatly broadened at right angles to the axis of coiling and irregularly polyhedral, a tubular projection developed from each of the angles with five as the maximum seen in the series of specimens studied.
Gerontic:-A very few of the largest specimens show an irregularity of the chamber somewhat greater than in the ordinary adults, and may perhaps represent a gerontic character. One of the largest specimens shows an actual reduction of the processes to three in the last-formed chamber after having attained an adult chamber with five processes.

The species has also occurred at several other localities in Manitoba. The "Chalk" was called the Cheval formation by McLean in 1916. Earlier writers have referred this formation to the Niobrara. There are very few megafossils in the formation, and none of these are good index fossils. The microfauna may be compared with the Taylor formation of Texas and the fauna described by Ehrenberg in his Mikrogeologie, 1854, which was probably from the Niobrara Chalk ,on the Missouri River. As numerous species of this fauna are known from the Gulf Series of Texas, it is to be expected that Hantkenina multispinata will later be found in that region.

The northernmost occurrence is in a band of calcareous shale on the south bank of the Vermillion River, 1/2 mile above the crossing of the trail into the Riding Mountain Forest Reserve. This occurrence occupies about the same stratigraphic position as the "Chalk" 150 miles further south. The range is limited to these beds, as no specimens were found from any other forma tion in the Prairie Provinces.

References:

Cushman, J. A. & Wickenden, R. T. D. (1930). The development of Hantkenina in the Cretaceous with a description of a new species. Contributions from the Cushman Laboratory for Foraminiferal Research. 6(2): 39-43. gs

CATALOG OF ORIGINAL DESCRIPTIONS: Hantkenina multispinata Cushman&Wickenden 1930

Hantkenina multispinata

References:

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