Taxon Concept provided by
| Taxon Concept provided by
|
|
| Home | Search | |
| TaxonConcept data set details: |
||||||
| Back to Search | ||||||
| . | ||||||
| Anonymous: Unedited TaxonConcept data | ||||||
| Notice: This catalogue page may contain unedited data.
| ||||||
Species Clavigerinella caucasica Subbotina 1958 | ||||||
|
|
||||||
| Diagnosis / Definition: | ||||||
|
Pearson et al. (2006): DESCRIPTION. Type of wall: Smooth normal perforate or weakly cancellate; characterized by pores with a wide range of diameters; possibly spinose. Test morphology: Planispiral or pseudoplanispiral, evolute, biumbilicate or showing a slightly raised spiral side and very shallow umbilicus; 4-4 1/2 rapidly enlarging chambers in the final whorl; early chambers rounded, final 1 -4 chambers radially elongate, digitate, peripheral outline strongly lobulate; distal chamber ends on final chambers acute, distinctly pointed; equatorial high arched aperture, symmetrical or slightly asymmetrical, bordered by smooth broad imperforate lips; web-like relict apertural lips often present along sutures; sutures shallow, straight, becoming curved in later stages, short compared to overall chamber length. Size: Diameter 0.75 mm, thickness 0.20 mm (Subbotina, 1958). |
||||||
| Discussion / Comments: | ||||||
|
Pearson et al. (2006): DISTINGUISHING FEATURES.- Clavigerinella caucasica differs froin other species of Clavigerinella by having adult chambers that taper into an acute or pointed tip (Subbotina, 1958). DISCUSSION.- Clavigerinella caucasica has commonly been regarded as a junior synonym of C. eocanica (e.g., Blow, 1979; Pearson, 1993). However, the occurrence of a number of specimens extremely close to the holoype of C. caucasica, which we illustrate in SEM for the first time (Pl. 8.2, Figs. 1-3), in the uppermost lower Eocene of the Austrian Helvetikum Section and Tanzania (Tanzanian Drilling Project Site 2; Pearson and others, 2004) indicates that it is a distinctive, recurring morphotype with a restricted range. Moreover, the pointed chambers appear to represent the first stage in the gradual morphological transition to Hantkenina (Coxall and others, 2003). PHYLOGENETIC RELATIONSHIPS.- This species probably evolved from C. eocanica in the latest early Eocene by slight tapering of the adult chambers. Hantkenina singanoae n. sp., which bridges the gap between digitate and tubulospinose morphologies, evolved from C. caucasica by further tapering and constriction of the chambers to form a pronounced terminal nub or proto-tubulospine. STRATIGRAPHIC RANGE.- Subbotina's holotype is simply listed as being Eocene in age. Our observations in Austria and Tanzania suggest a very restricted range in the uppermost part of early Eocene Zone E7. GEOGRAPHIC DISTRIBUTION.- Known only from the Caucasus Mountains, Austria and Tanzania. STABLE ISOTOPE PALEOBTOLOGY. No data available. |
||||||
| Systematics: | ||||||
|
35 Ordo Foraminiferida Superfamilia Globigerinaceae Familia Hantkeninidae Genus Clavigerinella |
||||||
| Synonym list: | ||||||
| Pearson et al. (2006): 1958 Hastigerinella caucasica Subbotina. - Subbotina : p.58 pl. 11; fig. 8a-b [middle Eocene,Belaya River,Northern Caucasus,
USSR]
2003 "Clavigerinella" Hantkenina transistons Coxall et al.. - Coxall et al. : p.250 pl. 6; fig. 5-8 [Zone P9-P10, topmost lower
Eocene to basal middle Eocene, Helvetikum Section,
Austria]
2006 Clavigerinella caucasica Subbotina. - Pearson et al. : p.220 pl. 8.2; fig. 1-8 (Pl. 8.2, Figs. 1-3: new SEMs of the holotype of
Hastigerinella caucasica Subbotina)
|
||||||
| Specimen: | ||||||
| All-Union Petroleum Scientific Research Geological Prospecting Institute - Leningrad, Inventory number: VNIGRI 440-58 |
||||||
| References: | ||||||
Subbotina,N.N. (1958): Coxall,H.K..; Huber,B.T. and Pearson,P.N. (2003): Pearson,P.N.; Olsson,R.K.; Hemleben,C.; Huber,B.T. and Berggren,W.A. (2006): |
||||||
| Anonymous: Unedited TaxonConcept data | ||||||
 This work is licensed under a Creative Commons Attribution 2.5 License. | ||||||
| Back to Search | ||||||
|
Taxon relations
Ranking (experimental) |
||||||