Daughter taxa (time control age-window is: 0-800Ma)
caucasica-aragonensis group (Eocene with muricocarina)
Morozovella caucasica Like M. crater but more strongly planoconical test with more chambers (usually 6-8) in the final whorl; umbilicus wider, and circumumbilical chamber margins strongly ornamented by fused muricae. It is strongly homeomorphic with M. velascoensis from the late Paleocene-early Eocene (Zone P3b-E2).
Morozovella crater Intermediate between M. lensiformis and M. caucasica - 4½ to 5 essentially equidimensional chambers in last whorl, thickened circumumbilical rim of elevated chamber shoulders, strongly limbate sutures on spiral side.
Morozovella aragonensis Like M. lensiformis but test planoconvex and with more chambers in final whorl (5-7) and nearly circular; terminal chamber generally smooth.
Morozovella lensiformis Test subquadrate, involute, biconvex, with narrow umbilicus; covered by blunt muricae, often obscuring the peripheral muricocarina; 4-4½ chambers in last whorl.
apanthesma-subbotinae group(weak keel)
Morozovella marginodentata Morphotype, with pronounced peripheral compression of the chambers on the umbilical side and a thick muricocarina formed form long muricae.
Morozovella formosa Like M. gracilis but test larger and more robust; more chambers in final whorl (6-7, rarely 8) and wider umbilicus.
Morozovella gracilis Like M. subbotinae but with lower spire and more chambers (5-6).
Morozovella subbotinae Like M. aequa but larger, with sronger muricocarina and more pronounced angulo-conical test; 4-4½ chambers in final whorl.
Morozovella aequa Like M. apanthesma but with less chambers (usually 4), more involute coiling (and so a more closed umbilicus) and a peripheral muricocarina.
Morozovella apanthesma Planoconvex, umbilicoconvex, test with lobulate, weakly muricocarinate periphery; 4-5 chambers in last whorl, inflated to subangular on umbilical side, moderately convex, triangular (lunate) in edge view; intercameral sutures on umbilical side depressed, radially curved and slightly depressed on spiral side; umbilical side distinctly muricate, coarsely perforate on spiral side; umbilicus relatively narrow, deep; aperture an interiomarginal, umbilical-extraumbilical arch with narrow, continuous intraperiumbilical lip.
angluata-velascoensis group (heavy muricate keel)
Morozovella edgari Like M. velascoensis but smaller and with weaker muricocarina. Very similar to juveniles of M. velascoensis and may have evolved from it by paedomorphosis.
Morozovella allisonensis Like M. velascoensis but axially compressed and less ornate; biconvex to mildly planoconvex in edge view; umbilical tips of chambers are relatively rounded and unornamented.
Morozovella acuta Like M. velascoensis but wth smaller umbilicus, weaker ornament and fewer chambers in final whorl (usually 5).
Morozovella occlusa Like M. acutispira but without raised early part of test.
Morozovella acutispira Like M. pasionensis but with development of a biconvex test; fewer chambers in the final whorl (4-6); and smaller umbilicus. Early part of test raised on spiral side.
Morozovella pasionensis Like M. velascoensis but with reduced spire height, a decrease in the ornament around the umbilicus, and an increase in the number of chambers (usually 5-7, up to 10).
Morozovella velascoensis Like M.conicotruncata but with coarsely muricate adumbilical ridges and muricocarina; and complete loss of muricae on the chamber surfaces.
Morozovella conicotruncata Like M.angulata (White) but test more planoconvex; umbilucs more open; and with a low rate of chamber enlargement, and so (5-7) equidimensional chambers in the final whorl.
Morozovella angulata Like M. praeangulata but with elaboration of the muricae, development of a peripheral muricocarina, and establishment of anguloconical chambers throughout the last whorl.
Morozovella praeangulata Planoconvex, moderately lobulate test with 5-6 tangentially elongate chambers in last last whorl; umbilical sutures straight to weakly curved, incised; spiral intercameral sutures incised, weakly muricate, strongly recurved; peripheral margin strongly muricate but not muricocarinate; umbilicus narrow, deep; aperture an interiomarginal, umbilical-extraumbilical slit (with distinct lip in well preserved specimens).
Morozovella sp. Specimens which cannot be assigned to established species
Taxonomy
Citation: Morozovella McGowran 1968taxonomic rank: GenusType species: Pulvinulinavelascoensis Cushman, 1925Taxonomic discussion: The morozovellids split into two lineages early in their evolution: (1) the M. angulata-M. velascoensis group characterized by the development of muricate adumbilical ridges, a strong muricocarina, and the absence of muricae on parts of the chamber surfaces; and (2) the M. apanthesma-M. subbotinae group whose members are initially unkeeled and entirely covered with fine, thin muricae. [Olsson et al. 1999]
For discusion of correct citation of the name see the taxonomic catalog.
Distinguishing features: Parent taxon (Truncorotaloididae): Muricate This taxon: Test typically plano-convex, chambers strongly anguloconical. Wall strongly pustulose (muricate) on parts of spire and umbilicus. Most species with muricocarina.
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: Test low trochospiral, lobulate outline; strongly anguloconical chambers throughout ontogeny; peripheral margin usually bears distinct muricocarina which passes continuously across at least one intercameral suture (absent or rudimentary in apanthesma); primary aperture interiomarginal, umbilical-extraumbilical; secondary apertures may be present on spiral side but typically lack apertural lips. [Eocene Atlas] Wall type: Normal perforate (pores cylindrical on at least part of the later chambers); some forms with weakly cancellate early chambers (a feature inherited from their praemuricate ancestry); adult chambers strongly pustulose (muricate) on parts of the spire and umbilicus. [Eocene Atlas]
Biogeography and Palaeobiology
Similar speciesGenus distinguished by muricate, anguloconical test and peripheral muricocarina (in nearly all taxa) of variable breadth and strength. [Eocene Atlas]
Geological Range: Last occurrence (top): at top of E9 zone (100% up, 43.2Ma, in Lutetian stage). Data source: Total of ranges of the species in this database First occurrence (base): within P2 zone (62.29-62.60Ma, base in Danian stage). Data source: Total of ranges of species in this database
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
Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 54
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
Cushman, J. A. (1925e). Some new foraminifera from the Velasco shale of Mexico. Contributions from the Cushman Laboratory for Foraminiferal Research. 1(1): 18-23. gs
Luterbacher, H. P. (1964). Studies in some Globorotalia from the Paleocene and Lower Eocene of the Central Apennines. Eclogae Geologicae Helvetiae. 57: 631-730. gsO
Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. (85): 1-252. gs
Morozovella compiled by the pforams@mikrotax project teamviewed: 10-9-2024
