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Diagnosis. - Test small, flat fan-like, resembling equilateral triangle, nearly smooth in outline, margin narrow, rounded, chambers wide and low, reniform, with nearly flat surface, strongly embracing each other especially in distal part. Sutures narrow, slightly depressed, poorly curved. Aperture low, semilunar with a narrow lip.
Description. - Test small, flat, resembling in shape equilateral triangle, fan-like, considerably but gradually increasing in size as chambers are added. Test outline nearly smooth, margin slightly rounded, test wall very thin, smooth, glittering, and with small pores. The initial, planispiral part of the test very small and composed of 4 spherical chambers; biserial part consists of 6 chambers, which are initially rectangular in outline, higher up reniform and strongly embracing each other. The youngest chambers tend to be uniserial (see paratype, pI. 11: 3a). Chambers are 3 times wider than high. Sutures are translucent, narrow, very poorly depressed and weakly arched. Median suture also translucent and poorly depressed, vanishing in a distal part of the test. Aperture low, semilunar with a narrow lip.
Size: holotype length 0.216mm
Etymology: from the name of the region where this species has been found.
Extra details from original publication
Variability. - Specimens of two generations are present in the investigated material. The two generations do not differ from each other, except for.the embryonic chamber. The latter is 5.1 µm large in microspheric generation, while being 15.6 µm large in macrospheric forms. The intraspecific variability concerns the width of the youngest chambers, which may be equal to the test width, but is usually less than this, and the presence or absence of median suture in a distal part of the test. In a distal part of the test, the chambers may be separated or fused with each other. Variability is also expressed in the number of chambers in both the planispiral portion of the test (from 3 to 5) and the biserial portion (from 6 to 8).
Remarks, - The species under discussion resembles Heterohelix glabrans (CUSHMAN) in the test shape and planispirally coiled initial part of the test. It differs from the last species in fan-like test shape, reniform chambers in a biserial part, nearly flat sutures, nearly smooth, not lobate test outline. In reniform shape of chambers and smooth test surface it resembles especially H. pulchra (BROTZEN) differing from it in fan-like shape, in chamber tendency to fuse with one another in the youngest portion of the test, in nearly smooth test outline, flat chamber surface and nearly flat sutures. The fan-like test shape and a tendency to disappearance of septal separation between chambers in the central part of the test recall very much a situation in Gublerina KIKOINE, 1948, which has additional chambers in the younger part of the test. H. suwalkensis is, thus, morphologically intermediate between two genera, Heterohelix and Gublerina. In configuration of the youngest chambers this species resembles Guembelina dagmarae SULEJ- MANOV, 1955, but differs' from this species in the test shape, hardly lobate test outline and in lack of septal separation between chambers in the central part of the test.
Distribution. - Poland, Polish Lowlands - Maastrichtian.
Gawor-Biedowa, E. (1992). . -. gs
Gawor-Biedowa, E. (1992). . -. gs
Heterohelix suwalkensis compiled by the pforams@mikrotax project team viewed: 16-4-2021
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