Lecture 11

Superfamily Globigerinacea

Superfamily Superfamily GlobigerinaceaGlobigerinacea

• The The planktonic Globigerinaceaplanktonic Globigerinacea typically have typically have trochospirally coiledtrochospirally coiled shells with inflated, shells with inflated, coarsely coarsely perforateperforate chambers being chambers being fine spinesfine spines during life during life (e.g. (e.g. HastigerinellaHastigerinella). ).

• The wall of the Globigerinacea is composed of The wall of the Globigerinacea is composed of optically optically radial and bilamellarradial and bilamellar, low magnesian , low magnesian calcitecalcite. .

• Although the Although the primary apertureprimary aperture is usually is usually basalbasal, , aerialaerial or or terminalterminal..

• Secondary sutural or Secondary sutural or aerialaerial aperturesapertures are also found. are also found.• These apertures may be partially covered by one or These apertures may be partially covered by one or

several flaps calledseveral flaps called bullae bullae..• Although inflated chambers are characteristic, some Although inflated chambers are characteristic, some

genera have genera have club-shaped (Clavate)club-shaped (Clavate) chambers chambers ((HastigerinoidesHastigerinoides), while others, including the ), while others, including the Rotaliporidae, Globotruncanidae and Globorotaliidae Rotaliporidae, Globotruncanidae and Globorotaliidae have have keeled outer marginskeeled outer margins ( (GlobotruncanaGlobotruncana; Upper ; Upper Cretaceous and Cretaceous and GloborotaliaGloborotalia, Paleocene – Recent)., Paleocene – Recent).

Superfamily Superfamily GlobigerinaceaGlobigerinacea

HastigerinellidaeHastigerinellidae RotaliporidaeRotaliporidae GlobotruncanidaeGlobotruncanidae GloborotaliidaeGloborotaliidae

• Ornament is not prominent but the Ornament is not prominent but the tests often have a tests often have a rugose or pustulose rugose or pustulose surfacesurface, and , and rarely longitudinal rarely longitudinal coastae. coastae.

• Forms which are Forms which are not trochospiralnot trochospiral include the include the ancestral Heteohelicidaeancestral Heteohelicidae (High trochospiral- biserial-uniserial, (High trochospiral- biserial-uniserial, ((HeterohelixHeterohelix, Upper Cretaceous and , Upper Cretaceous and the planispiral Hantkeninidae the planispiral Hantkeninidae ((HastigerinoidesHastigerinoides). ).

• Widely used for correlation are species Widely used for correlation are species of of GlobotruncanaGlobotruncana, , GloborotaliaGloborotalia, , GlobigerinaGlobigerina and and OrbulinaOrbulina. .

• The final, spherical orbuline, chamber The final, spherical orbuline, chamber of of OrbulinaOrbulina completely envelopes the completely envelopes the earlier, globigerine coil.earlier, globigerine coil.

a.Heterohelixa.Heterohelix

b.Hastigerinoidesb.Hastigerinoides

c.Globotruncanac.Globotruncana

d.Globorotaliad.Globorotalia

e. Globigerinae. Globigerina

f. f. OrbulinaOrbulina

Heterohelix Globotruncana arca

Globorotalia tosaensis Takayanagi and Saito

Orbulina universa

Globigerinoides ruber

Sphaeroidinellopsis subdehiscens (Blow)

Globigerinita dissimilis (Cushman and Bermudez(

Globigerinita glutinata

Superfamily RotaliaceaSuperfamily Rotaliacea • Tests of rotaliaceans are built of optically Tests of rotaliaceans are built of optically radial bilamelar radial bilamelar

calcitecalcite. . • They are distinguished by the presence of rotaliid septal flaps They are distinguished by the presence of rotaliid septal flaps

and canals. and canals. • In the commonly In the commonly brackish-waterbrackish-water genus genus AmmoniaAmmonia the the

umbilicus is partly filled by small calcite pillars. umbilicus is partly filled by small calcite pillars. • ElphidiumElphidium is another common genus, with an is another common genus, with an involute involute

planispiral testplanispiral test. A . A sutural canalsutural canal system opens at the surface system opens at the surface through through sutural poressutural pores, the latter defined by backward , the latter defined by backward projecting rods called projecting rods called retral processes.retral processes.

• CalcarinaCalcarina is a tropical genus in which the trochospiral test is a tropical genus in which the trochospiral test bears robust spines from a thick outer wall. bears robust spines from a thick outer wall.

• NummulitesNummulites are are rotaliacean larger foraminiferarotaliacean larger foraminifera widely used in widely used in correlating Eocene rockscorrelating Eocene rocks from around the old-world Tethys from around the old-world Tethys Ocean but their descendants are still found today in the Indo-Ocean but their descendants are still found today in the Indo-Pacific seas. Pacific seas.

• Their tests are Their tests are radial hyalineradial hyaline and and perforateperforate with with rotaliid septarotaliid septa. . • Coiling is biconvexCoiling is biconvex planispiralplanispiral..• Involute forms reveal V-shaped cavities in axial sections.Involute forms reveal V-shaped cavities in axial sections.

Ammonia

Elphidium Calcarina

Five main types of septal filament

on Nummulites tests

Detail of axial section,Nummulites

test and detail of spiral section

Spiroclypeus Nummulites obesus

Superfamily Superfamily CassidulinaceaCassidulinacea

• The Cassidulinacea comprise The Cassidulinacea comprise small small benthicbenthic foraminifera with optically foraminifera with optically granular, cryptolamellargranular, cryptolamellar calcite wallscalcite walls and and slit-tear-or-loop-shaped aperturesslit-tear-or-loop-shaped apertures, , generally generally arealareal or or terminalterminal. .

• In In CassidulinaCassidulina the test is lenticular, the test is lenticular, consisting of consisting of biserially arranged chambers biserially arranged chambers coiled in a plane spiralcoiled in a plane spiral. .

• Straight biserial followed by uniserial Straight biserial followed by uniserial growth is seen in growth is seen in LoxostomumLoxostomum. .

• VirgulinellaVirgulinella with supplementary sutural with supplementary sutural apertures.apertures.

• PleurostomellaPleurostomella is uniserial throughout, is uniserial throughout, with a terminal aperture and two "teeth".with a terminal aperture and two "teeth".

Cassidulina reniforme NørvangCassidulina carinata

PleurostomellaPleurostomella LoxostomumLoxostomum

VirgulinellaVirgulinellaCassidulinaCassidulina

Superfamily NonionaceaSuperfamily Nonionacea

• The wall structure of nonionacean The wall structure of nonionacean tests is of optically tests is of optically granular, crypto-granular, crypto-lamellar or bilamellar calcite. lamellar or bilamellar calcite.

• The aperture is generally The aperture is generally a basal slita basal slit. . • Two involute planispiral tests of the Two involute planispiral tests of the

genera genera NonionNonion and and MelonisMelonis differ differ largerly in largerly in the degree of chamber the degree of chamber inflataion. inflataion.

• In In OsangulariaOsangularia, the test is , the test is trochospiraltrochospiral with with a keela keel and and a closed a closed umbilicusumbilicus..

Nonion depresselum Meloni pompilioides

Osangularia-bengalensis

NonionNonion

MelonisMelonis OsangulariaOsangularia

Superfamily CarterinaeaSuperfamily Carterinaea • It represented by the single genus It represented by the single genus CarterinaCarterina. . • In this unusual foraminiferid the wall is composed of In this unusual foraminiferid the wall is composed of

monocrystalline calcite spicules arranged parallel monocrystalline calcite spicules arranged parallel within a calcite matrixwithin a calcite matrix. .

• The tests are distinguished after death and are The tests are distinguished after death and are not not known as fossils. known as fossils.

• The aperture of The aperture of CarterinaCarterina is large and is large and umbilicalumbilical in in position and the chambers are divided into chamberlets position and the chambers are divided into chamberlets by by septulae.septulae.

• It seems that is most closely related to the It seems that is most closely related to the discorbaceans.discorbaceans.