New species of Mesozoic benthic foraminifera from the former British Petroleum micropalaeontology collection

This paper describes five new Mesozoic, deep-water benthic foraminifera from the former British Petroleum microfossil reference collections at the Natural History Museum, London. The focus is on selected calcareous and agglutinating taxa that are of stratigraphical and/or palaeoecological significance for academic and industrial related activities. Ophthalmidium dracomaris (urn:lsid:zoobank.org:act:CCE951DF-0446-416B-AC2D-C5322CD335D2), Trochammina fordonensis (urn:lsid:zoobank.org:act:4F00A270-F9B2-46D4-8587-C7ADCC191D13), Eobigenerina calloviensis (urn:lsid:zoobank.org:act:B8443AA5-CFE4-44C0-A5A2-65EA97BF7EFA), Arenoturrispirillina swiecickii (urn:lsid:zoobank.org:act:06A35E03-5AA4-4363-B471-4E1A0091F62E) and Ataxophragmium mariae (urn:lsid:zoobank.org:act:B8443AA5-CFE4-44C0-A5A2-65EA97BF7EFA) are described with new illustrations. Their biostratigraphic and palaeoecological significance are briefly discussed.


Introduction
The North Sea Basin lies in between Scandinavia and northwestern Europe and is bounded by the continental shelf edge, approximately comparable to the region covered by the current North Sea today.It is a topographical low and can be divided into several sub-basins of late Palaeozoic through Cenozoic age (Carr, 2004).The area has an active tectonic history and deposition has varied between the different basins.Benthic foraminifera have been used extensively in the oil and gas industry to date the sediments and investigate the impact of environmental and palaeobathymetric changes on these semi-enclosed basins (Gradstein et al., 1994;Jenkins and Murray, 1989;King and Hughes, 1983).British Petroleum's exploration activities, especially in the UK sector, during the middle of the 20th century amassed a large volume of Mesozoic sample material and subsequently prepared micropalaeontological specimens, many of which are now housed at the Natural History Museum, London.The north-western European reference collection contains many of the specimens used in exploration activities and provides an almost unique collection of useful, yet in some instances formally un-described, foraminiferal taxa.
The taxonomy of the Cenozoic material from this collection has already been the focus of separate study (Fox et al., 2018).Presented here are five newly named species of Mesozoic benthic foraminifera which have academic and industrial value in their biostratigraphic and palaeoecological significance.

Materials
Light microscope images were taken using a Nikon SMZ25 stereoscopic zoom microscope and Nikon DS-Fi2 digital camera.SEM images were taken using uncoated specimens on a LEO 1455 VP scanning electron microscope.

Systematics
We present systematic data (descriptions, synonymies, biogeography and palaeoecologies) that were assembled from primary research, from the micropalaeontological literature, and also from consultation with specialists.Brief geological context is also provided, where available, for the well and/or outcrop where the type specimens were found.The taxonomic classification follows Loeblich and Tappan (1987) Published by Copernicus Publications on behalf of The Micropalaeontological Society.L. R. Fox et al.: New species of Mesozoic benthic foraminifera with a few exceptions which mainly reflect taxonomic updates published subsequently (Kaminski, 2014 Description: Test compressed, elliptical in outline; porcellaneous wall texture, periphery acute and weakly keeled; chambers almost invisible externally, half-whorl in length, rounded at the base and tapering slightly towards the aperture, margins almost parallel, sutures very weakly depressed; aperture is simple, circular, at the end of a long tapering neck, lacking a tooth. Remarks: Specimens were originally described by Coleman (1974;in Hortman et al., 1974) from the area around Milton Keynes, Buckinghamshire, and these have been described in some detail by Morris and Coleman (1989).Ophthalmidium dracomaris sp.nov.differs from O. compressum (Barnard, Cordey & Shipp, 1981)  Description: Test small, trochoid, flattened, very low spired, rounded in outline; consists of two whorls with eight to nine chambers in the final whorl, increasing gradually in size, flat on umbilical surface, convex on spiral side.Periphery acute, slightly lobate on margin.On the umbilical side only the final whorl is visible.Sutures are radial on umbilical side and slightly curved on the spiral side.Wall finely agglutinated with much cement; umbilical to extra-umbilical aperture with a lip, opening into umbilicus commonly obscured due to preservation.
Remarks: Trochammina fordonensis sp.nov. is similar to Trochammina aquilonaris Hedinger, 1993 in general morphology and size, but differs in having a flattened dorsal side and radial sutures on the umbilical side.Description: Test free, small, elongate in lateral outline and compressed; tapered at the base and rounded at the apertural end.Consists of two sections; initially biserial with six to seven slowly enlarging chambers; final two chambers are loosely biserial to lax-uniserial, not symmetrical, forming an uneven row with oblique sutures.Chambers in the uniserial part increase very little in size as added.Sutures are thin and depressed.Aperture terminal, in the form of a rounded opening on the slightly upwardly prolonged end of the last chamber.Wall finely agglutinated with grains less than 20 µm in size.

Remarks:
The genus Eobigenerina differs from Bigenerina in possessing organic cement that is silicified in fossil specimens.The Cenozoic genus Bigenerina possesses calcareous cement with pseudopores.Many of the late Paleozoic to Mesozoic species that were originally described as Bigenerina likely belong in Eobigenerina (Cetean et al., 2011).The chamber arrangement in the new species is initially biserial, becoming loosely biserial to lax-uniserial (sensu Kaminski et al., 2011) in the final chambers.This species differs from Bigenerina elongata (Gauger, 1953) and B. ciscoensis (Cushman and Waters, 1928)  Diagnosis: Single sub-rectangular to rectangular tubular chamber, coiling in a regular trochospire, with a circular outline.
Description: Test free, large; low conical spire, consisting of proloculus followed by single tubular chamber coiling in a low regular trochospire, outline circular, peripheral margin sub-rectangular to rectangular, occasionally developing angular keels; chamber size increasing gradually and uniformly, forming five to six whorls; spiral suture distinct and depressed; aperture arcuate opening at end of chamber; wall finely agglutinated, organic cement; surface finely roughened.
Remarks: This species was referred to as Spirillina limbata Brady by Heron-Allen and Earland (1910).However, examination of their hypotypes by Barr (1962) revealed the present species to be distinct, bearing only a superficial resemblance to the Recent S. limbata.Barr (1962) described this form as "Ammodiscoides heronalleni", but this name has never been published.This species was illustrated and described in Swiecicki's 1980 doctoral thesis in which it was removed from the genus Ammodiscoides Cushman (1909) as "it does not show the change from trochospiral to planispiral growth, characteristic of this genus" and was instead placed in Arenoturrispirillina Tairov (1956) on the basis of its "low, regular trochospiral coil".There have been several references (e.g.Cushman, 1946;Hofker, 1959) to Cretaceous occurrences of Ammodiscoides turbinatus (Cushman, 1909) originally described from the Holocene, Gulf of Mexico.This latter species, the genotype of Ammodiscoides, "lacks the regular trochospiral form" of the present species and therefore further investigation is required on these Cretaceous references (Sweicicki, 1980).
Dimensions: Height of test: 700 µm; diameter: 650 µm.Description: Test free; an asymmetrical low trochospiral coil with a tendency to planoconvexity, outline sub-spherical; two, occasionally three, whorls embracing, overlapping, evolute; chambers indistinct, moderately and uniformly increasing in size, may be slightly inflated, six per whorl several times higher than broad; last chamber often overlaps previous whorl both dorsally and ventrally; sutures distinct, flush; apertural face flat, making angle of approximately 65 • with previous whorl; aperture a deep, elongate, sub-rectangular slit along interiomarginal suture of last chamber, may show partial development of central lobe; interior most often simple, occasional forms show development of sutural buttresses; wall finely agglutinated, with calcareous cement; surface smooth.
Remarks: Marie (1941) originally described this rather distinctive species of Ataxophragmium, noting in particular its characteristic form and aperture.However, he referred to it as Nonionina globosa von Hagenow (1842), a form described, though never figured, from the Upper Cretaceous.Later workers, including Reuss (1862), Marsson (1878), Franke (1925Franke ( , 1927)), Cushman (1931), Schijfsma (1946) and Visser (1951), have all considered N. globosa to be calcareous and perforate, and it is herein considered to belong to the genus Gyroidinoides.The present form A. mariae is broadly similar in shape, but its wall character and aperture serve clearly to distinguish it.Schijfsma (1946) noted the above situation and erected Ataxogyroidina pseudoglobosa and included forms referred to by Marie as A. globosa in its synonymy.From his figures and descriptions, however, it is clear that A. pseudoglobosa (Schijfsma, 1946) is not conspecific with Marie's species nor with the (Tairov, 1959) forms herein described, lacking as it does the characteristic form, aperture and smooth surface.

Summary
Five new species of deep-water benthic foraminifera from the Mesozoic of north-western Europe are described from the ex-tensive reference collections at the Natural History Museum, London.These benthic foraminifera are important for their biostratigraphic and palaeoenvironmental value, hence their overdue formalized taxonomic descriptions.This study highlights the importance of both museum and industrial collections for their vast potential for new, publishable data, including new taxa and material from restricted and no-longer accessible locations.

Synonyms1941
Ataxogyroidina globosa (von Hagenow); Type level: Upper Campanian.Type locality: German Jura.Distribution: This species is moderately common in the upper Campanian on the Isle of Wight and Norfolk, UK.Etymology: Named in honour of Pierre Marie who first described this taxon.Holotype: NHMUK PM PF 74553.Paratypes: NHMUK PM PF 74554. ).
in possessing a shorter uniserial part and smaller test.