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Hantkenina primitiva Cushman & Jarvis 1929 from: Quilty, P.G.. (1976): Planctonic foraminifera DSDP Leg 34- Nazca Plata . DSDP initial reports Vol. 34
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Anonymous: Unedited TaxonConcept data
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Species Hantkenina primitiva Cushman & Jarvis 1929


Alternative name:
Diagnosis / Definition:
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, laterally compressed, somewhat evolute, often small for the genus; 5-7 closely appressed, rounded or polygonal chambers in the adult whorl, increasing steadily in size as added; peripheral outline is continuous or somewhat angular; first 1-3 chambers of the adult whorl are rounded, commonly pustulose and lack a tubulospine; final 2-5 chambers only are extend into hollow tubulospines; aperture is an equatorial arch, pinched laterally into a narrow slit, flaring at the base into lateral lobes, bordered by a wide imperforate lip; tubulospines positioned at or very close to the anterior chamber edge, usually spanning the suture between adjacent chambers and partially contacting the posterior wall of the adjacent youngest chamber, arising sharply from the supporting chamber; slender and tapering to a point, inclined forward in the direction of coiling. Size: Maximum diameter (excluding tubulospines) 0.20-40 mm.
Discussion / Comments:
Toumarkine & Luterbacher (1985):
Hantkenina primitiva differs from H. alabamensis mainly by the ontogenetically late development of the spines which are present only in the last 2 or 3 chambers. According to Blow (1979), this phenomena probably represents a regressive feature. In addition, H. primitiva is distinguishable from H. alabamensis by its more embracing and laterally more compressed chambers.
Pearson et al. (2006):
DISTINGUISHING FEATURES .- Hantkenina primitiva is distinguished from H. compressa by the absence of tubulospines on early adult chambers and the generally smaller test size. It is distinguished from H. australis by having straight rather than recurved tubulospines and lacks the forward leaning arrangement of tubulospines and lateral chamber inflation characteristic of H. alabamensis. DISCUSSION.- Hantkenina primitiva is a variable form representing the trend in some late middle and late Eocene hantkeninids for the shell to become more evolute and for the tubulospines to form later in ontogeny (i.e. the early final whorl chambers genuinely lack tubulospines and are not broken-off, as is more commonly the case in hantkeninids). Blow (1979) regarded this feature as 'regressive' or 'phylogerontic', recapitulating what he considered to be the ancestral Pseudohastigerina condition. In contrast to Blow, we consider Hantkenina to be a monophyletic clade that evolved from the Clavigerinelln group rather than Pseudohastigerina (Coxall and others, 2003), and therefore suggest these characters are the result of changes in the timing of developmental processes. Some forms displaying a reduced number of tubulospines are significantly smaller than the holotype specimen (0.20-30 mm). These 'dwarf' morphotypes tend to have a total of only 8-9 chambers, compared to the usual 10-13 chambers that make up the shells of most species of Hantkenina (Coxall, 2000). It is possible that these represent juvenile stages; however, we note that small forms are most common in the upper middle and upper Eocene and mainly occur in continental shelf environments, e.g., Ecuador (Hofker, 1956), New Zealand and the New Jersey, suggesting that this form is a distinctive variety with particular oceanographic preferences. Under this taxonomy H. primitiva is retained in the strict sense (H. primitiva sensu stricto) outlined in the original descrktion and exemplified by the holotype, but it also incfudes the dwarf variety (H. primitiva sensu lato). The dwarf variety may prove to be of paleoenvironmental significance. PHYLOGENETIC RELATIONSHIPS.- Hantkenina primitiva may have evolved from H. compressa at the base of Zone E13. STRATIGRAPHIC RANGE.- Base of Zone E13 to the Eocene/Oligocene boundary. GEOGRAPHIC DISTRIBUTION.- Global, most common in shelf environments and at the periphery of the hantkeninid latitudinal range. H. primitiva sometimes dominates otherwise impoverished planktonic foraminiferal assemblages. STABLE ISOTOPE PALEOBIOL0GY.- No data available.
Quilty (1976):
Remarks: Some of the specimens referred to could belong to Cribrohantkenina inflata
Systematics:

15
 Classis Foraminifera
  Genus Hantkenina
   Species Hantkenina primitiva

35
  Ordo Foraminiferida
   Superfamilia Globigerinaceae
    Familia Hantkeninidae
     Genus Hantkenina
      Species Hantkenina primitiva
Synonym list:
Toumarkine & Luterbacher (1985):
1929 Hantkenina alabamensis var. primitiva Cushman & Jarvis. - Cushman & Jarvis : p.16 pl 3 fig 3 (type reference)
1985 Hantkenina primitiva Cushman & Jarvis. - Toumarkine & Luterbacher : p.124 figs 25.13-15
Pearson et al. (2006):
1929 Hantkenina alabamensis var. primitiva Cushman & Jarvis. - Cushman & Jarvis : p.16 pl. 3; fig. 2-3 [Eocene, Mt. Moriah beds, Vistabella Quarry, Trinidad]
1950 Hantkenina (Hantkenina) primitiva Cushman. - Brönnimann : p.416 pl. 56; fig. 4, 26, 27 [upper Eocene, San Fernando Gp., Trinidad; Oceanic Fm., Barbados]
1969 Hantkenina primitiva Cushman & Jarvis. - Samanta : p.340 pl. 1; fig. 9a-b [Globorotalia cerroazulensis Zone, Kopili Fm., Assam, India]
non 1979 Hantkenina (Hantkenina) primitiva Cushman. - Blow : p.1161 pl. 243; fig. 4 [upper Eocene, Zone P 16, Lindi, Tanzania]; (= H. compressa)
1988 Hantkenina alabamensis Cushman. - Coccioni : p.85 pl. 1; fig. 1-9 [upper Eocene, Massignano stratotype section, Italy]; [Not Cushman, 1924]
2006 Hantkenina primitiva Cushman & Jarvis. - Pearson et al. : p.248 pl. 8.12; fig. 1-20 (Pl. 8.12, Figs. 1-2: new SEMs of the holotype of Hantkenina primitiva Cushman and Jarvis)
Quilty (1976):
1929 Hantkenina primitiva Cushman & Jarvis. - Cushman & Jarvis : p.16 pl. 3, figs. 2-3
1976 Hantkenina primitiva Cushman & Jarvis. - Quilty : p.703 pl. 19, fig. 8
Specimen:
Cushman Collection - Smithsonian Museum of Natural History, Washington, D.C., Inventory number: USNM 10067
References:

Cushman,J.A. and Jarvis,P.W. (1929):
New foraminifera from Trinidad . Contributions from the Cushman Foundation for Foraminiferal Research Vol. 5 p. 6-17

Brönnimann,P. (1950):
The Genus Hantkenina Cushman in Trinidad and Barbados, B.W.I. . Journal of Paleontology Vol. 24 p. 397-420

Samanta,B.K. (1969):
Eocene planktonic foraminifera from the Gargo Hills, Assam, India . Micropalaeontology Vol. 15 p. 325-350

Quilty,P.G.. (1976):
Planctonic foraminifera DSDP Leg 34- Nazca Plata . DSDP initial reports Vol. 34

Blow,W.H. (1979):
The Cainozoic Globigerinida. 3 Vols p. 1413 pp

Toumarkine,M. and Luterbacher,H.P. (1985):
Paleocene and Eocene Planktic Foraminifera.
In: Plankton Stratigraphy p. 87-154

Coccioni,R. (1988):
The genera Hantkenina and Cribrohantkenina (Foraminifera) in the Massignano section (Ancona, Italy).
In: The Eocene-Oligocene Boundary in the Marche-Umbria Basin (Italy), Ancona International Subcommission on Paleogene Stratigraphy, Special Publication II Vol. 2 Eds: Premoli Silva, I.Coccioni, R.Montanari, A.. p. 81-96

Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006):
Atlas of Eocene Planktonic Foraminifera. p. 1-513
Anonymous: Unedited TaxonConcept data
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