Hastigerinellaeocanica var. aragonensis Nuttall, 1930:290, pl. 50: figs. 9-11 [lower Eocene, Arrayo region, Mexico].
Hastigerinellaeocanica Nuttall.—Stainforth, 1948:116-117, pl. 26: figs. 18, 19 (detached chambers) [upper Eocene, Ecuador].—Weiss, 1955:309, pl. 2: figs. 11-13 [middle Eocene Talara, Chira and Mirador Fms, Northern Peru]. [Not Nuttall, 1930.]
Not Clavigerinellajarvisi (Cushman). —Postuma, 1971:132, pl. on p. 133: 4 specimens, right hand column [Eocene Globorotaliabullbrooki Zone to Globigerapsiskugleri Zone, Navet Fm. Trinidad] (= Clavigerinellaeocanica)
Taxonomic discussion: Blow (1979) did not subdivide Clavigerinella based on chamber length, believing this character to be a function of growth stage and environmental factors, hence he placed C. jarvisi in synonymy with C. eocanica. Our observations of Clavigerinella from a number of sites (ODP Sites 865, 960, 1218, Kane 9-C) indicate that a C. jarvisi morphotype with long finger-like chambers can be distinguished from the moderately clavate form C. eocanica. Complete specimens of this species are extremely rare and it is usually recognised by the detached digitate adult chambers, which are easily recognized by the porous chamber surface and remnants of the apertural arch (Pl.8.2, Figs. 8, 9). We find no evidence for the presence of “roughened projections” representing spine bases as indicated by Cushman’s (1930) original description and find no link to the modern digitate form Hastigerinelladigitata. [Coxall & Pearson 2006]
Distinguishing features: Parent taxon (Clavigerinella): Final chambers clavate. This taxon: Final chambers elongate and slender, without terminal swellings
NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They are being edited as the site is developed and comments on them are especially welcome.
Description
Morphology: Planispiral or pseudoplanispiral, evolute, biumbilicate or showing a slightly raised spiral side and very shallow umbilicus; 4- 4½ chambers in the final whorl; increasing rapidly in size as added, early chambers rounded, final 2-3 chambers rapidly elongating into slender, cylindrical fingers (digitate); distal chamber ends smooth and rounded or slightly tapered; equatorial high arched aperture, symmetrical or slightly asymmetrical, bordered by a broad imperforate lip; sutures shallow, straight, becoming curved in later stages, short compared to the overall chamber length. [Coxall & Pearson 2006] Wall type: Usually smooth, normal perforate, sometimes weakly cancellate; possibly spinose in life. [Coxall & Pearson 2006] Size: Up to 0.545 mm (Cushman, 1930). Detached chambers can be 0.4 mm, suggesting some specimens are as large as 1 mm. [Coxall & Pearson 2006]
Character matrix
test outline:
Stellate
chamber arrangement:
Pseudoplanispiral
edge view:
Equally biconvex
aperture:
Equatorial
sp chamber shape:
Elongate
coiling axis:
Low
periphery:
N/A
aperture border:
Thick lip
umb chbr shape:
Elongate
umbilicus:
Wide
periph margin shape:
N/A
accessory apertures:
None
spiral sutures:
Weakly depressed
umb depth:
Shallow
wall texture:
Smooth
shell porosity:
Microperforate: <1µm
umbilical or test sutures:
Weakly depressed
final-whorl chambers:
4-4.5
N.B. These characters are used for advanced search. N/A - not applicable
Biogeography and Palaeobiology
Geographic distributionWorldwide in low and mid-latitudes. Rare in oligotrophic open ocean sections, occasionally common in upwelling assemblages. Based on the occurrence of common C. jarvisi (recorded as C. eocanica) together with radiolarian-rich sediments in Peru and Ecuador, Stainforth (1948) suggested this species thrived in the cold waters of northward flowing ex-polar currents. His claim that this species is a strictly cold-water specialist cannot be substantiated, however, since it has never been found in polar regions. More likely, the occurrence of C. jarvisi was linked to western continental margin upwelling. [Coxall & Pearson 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Coxall & Pearson (2006) Isotope paleobiologyNo data available. [Coxall & Pearson 2006] Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline. Based on very light _13C and very heavy _18O. Sources cited by Aze et al. 2011 (appendix S3): Coxall et al. (2000) Phylogenetic relationsThis species probably evolved from C. eocanica in uppermost Zone E7 by extension and tapering of the final chambers. [Coxall & Pearson 2006]
Most likely ancestor:Clavigerinella eocanica - at confidence level 3 (out of 5). Data source: Coxall & Pearson (2006), fig 8.1.
Biostratigraphic distribution
Geological Range: Notes: Zone E7-E10. Last occurrence poorly constrained. [Coxall & Pearson 2006] Last occurrence (top): in mid part of E10 zone (50% up, 42.6Ma, in Lutetian stage). Data source: Coxall & Pearson (2006), fig 8.1 First occurrence (base): in upper part of E7a subzone (80% up, 48.7Ma, in Ypresian stage). Data source: Coxall & Pearson (2006), fig 8.1
Plot of occurrence data:
Range-bar - range as quoted above, pink interval top occurs in, green interval base occurs in.
Triangles indicate an event for which a precise placement has been suggested
(NB There is no histogram as there are no occurrence records for the taxon in the Neptune database) Parent: Clavigerinella
Primary source for this page: Coxall & Pearson 2006 - Eocene Atlas, chap. 8, p. 224
References:
Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs
Coxall, H. K. & Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of the Hantkeninidae (Clavigerinella, Hantkenina and Cribrohantkenina). In, Pearson, P. N., Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication . 41(Chap 8): 213-256. gsO
Cushman, J. A. (1930). Fossil species of Hastigerinella. Contributions from the Cushman Laboratory for Foraminiferal Research. 6(1): 17-19. gs
Nuttall, W. L. F. (1930). Eocene Foraminifera from Mexico. Journal of Paleontology. 4: 271-293. gs
Stainforth, R. M. (1948a). Applied micropalaeotology in coastal Ecuador. Journal of Paleontology. 22: 113-151. gs
Weiss, L. (1955b). Planktonic index foraminifera of northwestern Peru. Micropaleontology. 1: 301-319. gs
Clavigerinella jarvisi compiled by the pforams@mikrotax project teamviewed: 14-12-2024
Eocene_Atlas_pl08-2_fig15-16.jpg
Eocene_Atlas_pl08-2_fig15-16.jpg
holotype: H. jarvisi
holotype: H. jarvisi
x: H. jarvisi
