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Species Hantkenina nanggulanensis Hartono 1969 | ||||||
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| Diagnosis / Definition: | ||||||
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Pearson et al. (2006): DESCRIPTION. Type of wall: Smooth, normal perforate and probably nonspinose; tubulospines imperforate, smooth or with fine striations. Test morphology: Planispiral, biumbilicate, strongly inflated and very large for the genus; 5-6 closely appressed, spherical or polygonal chambers in the adult whorl, increasing rapidly in size as added, becoming highly inflated in the final stages; peripheral outline (excluding tubulospines) is lobed or angular; adult chambers extended into a hollow tubulospine; sutures depressed and curved; umbilicus deep and restricted; aperture shape is variable, laterally pinched into a narrow slit with flaring basal lobes or open and triangular, symmetrical (as is typical for-zarlier hantkeninids) or asymmetrical, with folds and invaginations in the margin and lip; tubulospines short and triangular or long and slender, ends tapering to a point, positioned at the anterior chamber edge, spanning the suture between chambers; arising sharply from the supporting chamber and inclined forward in the direction of coiling at a low angle almost tangential with respect to the periphery in the final stages and contacting adjacent younger chambers along their outer periphery, penultimate tubulospines may be completely enveloped by globular younger chambers. Size: Maximum diameter of the holotype (excluding tubulospines) is 0.47 mm (Hartono, 1969). |
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| Discussion / Comments: | ||||||
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Pearson et al. (2006): DISCUSSION.- This morphospecies is transitional between Hantkenina alabamensis and Cribrohantkenina injlata. The chambers of the final whorl are highly inflated, as in C. injlata, but the species lacks additional area1 apertures. In some specimens the apertural opening and surrounding lip becomes irregularly folded and invaginated to form lobes of the primary aperture (Pl. 8.1 1, Fig. 18), a condition that probably represents the transition to the more complex multiple aperture system of Cribrohantkenina. Formerly this morphotype has usually been included in H. alabamensis; however, we observe that it is stratigraphically and morphologically distinct from the latter and thus merits specific status. Bronnimann (1950) remarked in his distinction of H. suprasuturalis that his species is generally larger and much more inflated than H. alabamensis, suggesting that it might be a prior synonym of H. nanggulanensis. However, the holotype of H. suprasuturalis is a peculiar specimen with a very angular peripheral outline and is not the typical upper Eocene morphospecies we recognise here as H. nanggulanensis, nor is it significantly more inflated than the holotype of H. alabamensis. The name nanggulanensis has rarely been used outside its type locality. We have been unable to study the holotype but the type illustrations are good and we have collected comparable specimens from the type Nanggulan Formation (see Plate 8.11). PHYLOGENETIC RELATIONSHIPS.- Evolved from H. alabamensis by inflation of the chambers and widening of the arched equatorial aperture in uppermost Zone E13. STRATIGRAPHIC RANGE.- Late Eocene, uppermost Zone E 13 to the Eocene/Oligocene boundary. GEOGRAPHIC DISTRIBUTION.- Worldwide, lowmid latitude open-ocean and marginal paleoenvironments. STABLE ISOTOPE PALEOBIOLOGY.- Pearson and others (2001) recorded this species with isotopic values intermediate between other CO-occurring species. Hantkenina spp. analyzed together from Zone P15 have lower ō18O and higher ō13C than all other species analyzed, suggesting a surface mixed-layer depth habitat (Coxall and others, 2000). |
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| Systematics: | ||||||
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35 Ordo Foraminiferida Superfamilia Globigerinaceae Familia Hantkeninidae Genus Hantkenina Species Hantkenina nanggulanensis |
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| Synonym list: | ||||||
| Pearson et al. (2006): 1962 Hantkenina (Hantkenina) suprasuturalis Brönnimann. - Ramsay : p.85 pl. 16; fig. 12a-b, 13, 14, 18 [middle Eocene, Tanganyika, Samples WA 1960;
1963, Kilwa Masoko area]; [Not Brönnimann, 1950]
1969 Hantkenina nanggulanensis Hartono. - Hartono : p.154 pl. 20; fig. 3-4 [upper Eocene, Kebon Agung, Nanggulan
region, Java]
2006 Hantkenina nanggulanensis Hartono. - Pearson et al. : p.247 pl. 8.11; fig. 1-18 (Pl. 8.1 1, Figs. 1, 2: original illustration of the
holotype of Hantkenina nanggulanensis Hartono)
(Pl. 8.11, Fig. 3: original illustration of the paratype
of Hantkenina nanggulanensis Hartono)
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| Specimen: | ||||||
| Paleontological Collection of the Geological Survey of Indonesia - Bandung, Inventory number: P.D. 5104 |
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| References: | ||||||
Ramsay,W.R. (1962): Hartono,H.M.S.. (1969): Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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