CATALOG OF ORIGINAL DESCRIPTIONS: Acarinina mattseensis subsp. alticonica Fleisher 1974

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 mattseensis alticonica
Other pages this level: A. acarinata, A. boudreauxi, A. clara, A. compacta, A. crassaformis similata, 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, > >>

Acarinina mattseensis alticonica

Citation: Acarinina mattseensis subsp. alticonica Fleisher 1974
Rank: sub-species
Type locality: Holotype and figured paratypes from 68-70 cm. depth in Section 2, Core 16 (288-297 m. below the sea bottom) from Hole 220 of Deep Sea Drilling Project Leg 23, drilled in waters 4036 m. deep at lat. 6 degrees30.97' N., long. 70 degrees59.02' E., in the sou
Type level: Lower Eocene, Zone P.8. DSDP 229-16-2, 68-70 cm.
Holotype Repository: USNM

Linked specimens: USNM-211525 USNM-211528 USNM-211526 USNM-211527

Current identification/main database link: Acarinina alticonica Fleisher 1974


Original Description: The test is small, compact, and rounded in ventral outline, with chambers arranged in a moderately high trochospire. Four and occasionally four and one-half or five chambers are present in the final whorl. The test wall is coarsely perforate with weakly developed pseudospines. These spine-like projections, however, are prominent and distinct in the umbilical region. While the wall is thick, it does not have the appearance of a secondary crust. The chambers are slightly inflated, but the intercameral and spiral sutures are marked only by very low depressions and are indistinct except between the chambers of the ifnal whorl. On the dorsal side, the distinct and elevated trochospire formas a rounded and subconical projection, but the chambers of the early whorls are indistinguishable because of the thickened wall. Dorsal sutures in the final whorl are straight and radial to slightly tangential. The periphery is very broadly rounded and is unrecognizable as a distinct region. The umbilicus is usually distinct and nearly round to subquadrate, but in some specimens it may take the form of an irregular elongate slit. Ventral sutures are somewhat depressed and slightly more distinct than those on the dorsal surface, and in ventral view the chambers are subglobular. The aperture is a low-arched opening within the umbilicus at the base of the apertural face. Dimensions of figured specimens. - Holotype: Maximum diameter 0.31 mm., axial elevation 0.30 mm. Paratype: Maximum diameter 0.27 mm. Paratype: Maximum diameter 0.26 mm. Remarks: Acarinina mattseensis alticonica Fleisher is somewhat similar, in overall form, to Globigerinatheka senni (Beckmann) [Sphaeroidinella senni, 1954] (Fleisher, 1974, op. cit., pl. 8, figs. 10,11). The wall in the former is much less thickened and crystalline and does not have the crust-like appearance which led Beckmann (1954, Eclogae Geol. Helv., vol. 46 (1953), no. 2, pp. 393, 394) to assign his species to Sphaeroidinella. The chambers in g. senni are somewhat more distinct, and the pustules around the umbilicus much more pronounced than in A. mattseensis alticonica. The latter species I salso typically considerably smaller. Although a. mattseensis alticonica appears one zone earlier than G. senni, the similarity of the two forms should probably be considered isomorphic in nature. Evidence presented in connection with G. senni suggests that it evolved from a different form altogether. The wall structure and test shape of a. mattseensis alticonica are roughly similar to that of a. mattseensis s.s. (Gohrbandt) [Globorotalia mattseensis, 1967], from which it differs in having more chambers and a higher dorsal coil. Gohrbandt (1967, Micropaleontology, vol. 13, no. 3, pl. 322) suggested the evolution of the latter taxon from A. broedermanni (Cushman and Bermudez) [Globorotalia (Truncorotalia) brodermanni, 1949] near the Early-Middle Eocene boundary. It appears likely, however, that A. mattseensis s.s. and A. mattseensis alticonica are closely related, and the latter may have given rise to the former. A. mattseensis wartsteinensis (Gohrbandt) [Globorotalia wartsteinensis, 1967], evolved from the nominate subspecies as a continuation of the apparent trend toward flattening of the dorsal surface and increasing number of chambers in the final whorl.

Holotype size: Maximum diameter of the holotype is 0.31 mm and axial elevation is 0.30 mm.

Extra details from original publication: Remarks: A. mattseensis alticonica n.sp. is somewhat similar, in overall form, to Globigerinatheka senni (Beckmann) (pi. 8, figs. 10, 11). The wall in the former is much less thickened and crystalline and does not have the crust-like appearance which led Beckmann (1953) to assign his species to Sphaeroidinella. The chambers in G. senni are somewhat more distinct, and the pustules around the umbilicus much more pronounced than in A. mattseensis alticonica. The latter species is also typically considerably smaller. Although A. mattseensis alticonica appears one zone earlier than G. senni, the similarity of the two forms should probably be considered isomor- phic in nature. Evidence presented in connection with G. senni suggests that it evolved from a different form altogether. The wall structure and test shape of A. mattseensis alticonica are roughly similar to that of A. mattseensis s.s. (Gohrbandt), from which it differs in having more chambers and a higher dorsal coil. Gohrbandt (1967) suggested the evolution of the latter taxon from A. broedermanni (Cushman and Bermudez) near the Early-Middle Eocene boundary. It appears likely, however, that A. mattseensis s.s. and A. mattseensis alticonica are closely related, and the latter may have given rise to the former. A. mattseensis wartsteinensis (Gohrbandt) evolved from the nominate subspecies as a con- tinuation of the apparent trend toward flattening of the dorsal surface and increasing number of chambers in the final whorl.

Etymology: The subspecies name alticonica refers to the distinctive and characteristic high trochospire.

References:

Fleisher, R.L., (1974). Cenozoic planktonic foraminifera and biostratigraphy, Arabian Sea, Deep Sea Drilling Project, Leg 23A. Initial Reports of the Deep Sea Drilling Project, 23: 1001-1072.


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Acarinina mattseensis alticonica compiled by the pforams@mikrotax project team viewed: 23-8-2017

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