CATALOG OF ORIGINAL DESCRIPTIONS: Acarinina mcgowrani Wade & Pearson, in Berggren et al. 2006

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: pf_cat -> A -> Acarinina -> Acarinina mcgowrani
Other pages this level: A. acarinata, A. boudreauxi, A. clara, A. compacta, A. crassaformis simulata, A. discors, A. falsospiralis, A. inaequiconica, A. indolensis, A. intermedia, A. interposita, A. kiewensis, A. mattseensis alticonica, A. mcgowrani, A. microsphaerica, A. multicamerata, A. multiloculata, A. pentacamerata acceleratoria, A. pentacamerata camerata, A. pentacamerata erevanensis, A. planodorsalis, A. praecursoria, A. primitiva, A. proxima, A. pseudosubsphaerica, A. pseudotopilensis, A. punctocarinata, A. quadratoseptata, A. rotundimarginata, > >>

Acarinina mcgowrani

Citation: Acarinina mcgowrani Wade & Pearson, in Berggren et al. 2006
Rank: Species
Type locality: Kitunda, Tanzania;
Type age: Zone P14
Type sample and level: Sample Lin 99-17
Holotype Repository: Washington; USNM
Type & figured specimens: PLATE 9.13, FIGURES 1-16; Holotype (USNM 528417) and paratypes (USNM 528418, 528419)

Linked specimens: USNM-528418 USNM-528417 USNM-528419

Current identification/main database link: Acarinina mcgowrani Wade & Pearson, in Berggren et al. 2006


Original Description
Wall type: Densely muricate, nonspinose, normal perforate.

Test morphology: Chambers arranged in a moderate trochospiral, test compact with 2 whorls, typically 4 (but ranging from 3-4½) chambers in the final whorl, gradually increasing in size; peripheral outline weakly lobate; chambers on umbilical side, wedge-shaped or triangular, with final chamber oval in umbilical view, typically twice as long as high, and subrounded to angular in edge view; chambers densely muricate, with large, conical muricae concentrated in the circum-cameral region of the final chamber, but not fused into muricocarina; sutures distinct, deeply incised and radial; umbilical-extraumbilical aperture set in a deep umbilicus; bullae common; on spiral side chambers subrectangular or ovoid; supplementary apertures frequently occur, fringed by thin muricae; sutures incised, radial to weakly curved; sutures of both sides are commonly intruded by slender muricae; strong tendency for a preferred coiling direction, either dextral or sinistral, depending on the location and stratigraphic level.

Size: Maximum diameter of holotype 0.25-0.30mm.

Etymology: Named in honor of Professor Brian McGowran of University of Adelaide for his contributions to the taxonomy of Paleogene foraminifera.

Extra details from original publication
Synonyms: Taxonomic discussion: Despite being abundant throughout almost the whole of the middle Eocene, Acarinina mcgowrani n. sp. has not been formally recognized as a distinct species. Previous studies (e.g., Wade and others, 2001; Wade and Kroon, 2002; Wade, 2004; Pearson and others, 1993, 2001, 2004) have used a broad concept of either A. praetopilensis or A. pseudotopilensis to accommodate these highly muricate, compact forms. However, following study of type material from Russia, we now recognize A. pseudotopilensis to be a stratigraphically restricted component of early Eocene assemblages. The distinctive features of A. praetopilensis, as described by Blow (1979), include a circum-cameral muricocarina and angular final chamber similar to A. topilensis. These features also necessitate a restricted concept, hence the need for a new species.

Geographic distribution: Widely distributed, but most abundant in low and mid latitudes, common in central equatorial Pacific Ocean (ODP Site 865), North and South Atlantic Ocean (ODP Sites 1051 and 1052, DSDP Site 523) and Tanzania. 

Isotope paleobiology: Relatively negative ∂18O and positive ∂13C values indicate a mixed layer habitat. Size fraction data shows a large change in ∂13C through ontogeny suggestive of a symbiotic relationship like other muricate forms; Pearson and others, 1993 (recorded as pseudotopilensis); Wade and Kroon, 2002; Wade 2004 (recorded as praetopilensis). 

Phylogenetic relations: Acarinina mcgowrani evolved from A. pseudotopilensis near the base of the middle Eocene and gave rise to A. praetopilensis.

Geological Range: Acarinina mcgowrani characterizes almost the whole of the middle Eocene. It evolved in Zone E7 and was one of the final large acarininids to become extinct, which just preceded the extinction of Morozovelloides in upper Zone E13 (Wade, 2004).

References:

Berggren, W. A., Pearson, P. N., Huber, B. T. & Wade, B. S. (2006b). Taxonomy, biostratigraphy, and phylogeny of Eocene Acarinina. 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 9): 257-326. gs

Pearson, P. N., Shackleton, N. J. & Hall, M. A. (1993). Stable isotope paleoecology of middle Eocene planktonic foraminifera and multi-species isotope stratigraphy, DSDP Site 523, South Atlantic. Journal of Foraminiferal Research. 23: 123-140. gs

Pearson, P. N. et al. (2001a). Warm tropical sea surface temperatures in the Late Cretaceous and Eocene epochs. Nature. 413: 481-487. gs

Pearson, P. N. et al. (2004). Paleogene and Cretaceous sediment cores from the Kilwa and Lindi areas of coastal Tanzania: Tanzania Drilling Project Sites 1–5. Journal of African Earth Sciences. 39: 25-62. gs

Wade, B. S. & Kroon, D. (2002). Middle Eocene regional climate instability: Evidence from the western North Atlantic. Geology. 30: 1011-1014. gs

Wade, B. S. (2004). Planktonic Foraminiferal biostratigraphy and mechanisms in the extinction of Morozovella in the Late Middle Eocene. Marine Micropaleontology. 51: 23-38. gs

Wade, B. S., Kroon, D. & Norris, R. D. (2001). Orbitally forced climate change in the Late Middle Eocene at Blake Nose (Leg 171B): Evidence From Stable Isotopes In Foraminifera. Geological Society of London, Special Publications. 183: 273-291. gs


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Acarinina mcgowrani compiled by the pforams@mikrotax project team viewed: 29-1-2020

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