Marine Invertebrate PaleoKingdom Protista

Single Celled Eukaryotes

Primary Producers/AutotrophsCoccolithophores

Kingdom: Protista Division: Chrysophyta (golden-brown algae) Class: Coccolithophyceae

Unicellular, photosynthetic biflagella-bearing organisms

Produce calcareous skeletal plates called coccoliths

Mineralogy calcite

Test called the coccosphereNannoplankton (5-60 mm in size)

< 200 m depth, need sunlightGeologic range: Common early Jurassic to

PresentK/T event greatly affected their diversity (4-5

spp. survive)Good biostratigraphic indicatorsUse a third appendage called the haptonema

to attach to a substrate.

ReproductionAsexual

Longitudinal fission of the cell Multiple fission of the cell

EcologyTropics to temperate open-oceanGeographic distribution controlled by:

Light Salinity Water temperature Circulation patterns

Photoautotrophs continuedDiatoms

Kingdom Protista Division: Chrysophyta

Class: BacillariophyceaeGeologic Range: Jurassic to RecentBivalved test called Frustules

Epitheca Hypotheca

Mineralogy Opal-A (SiO2-nH2O)

Two Morphological GroupsCentrales (centric) “circular”

Generally planktonicPennales (elongate) “football” shaped

Generally benthic

Occur in all environmentsFreshwaterMarineTerrestrial/soilsAir

ReproductionAsexual

Simple binary fission (always new hypotheca) Followed by sexual spore formation

EcologyPhotic zone <200 mDiatom blooms 106 cells/LiterNormal 103-104 cells/Liter

Diatomites Deposits composed of frustules

Upwelling zones sub-arctic and sub-antarctic

Question?If diatoms and coccolithophores did not

evolve until Jurassic time what was the major primary producer in the Paleozoic?

1) Dinoflagellates (Silurian-Recent)

2) Acritarchs (Precambrian-Early Mesozoic)(~2.0 b.y.a)

DinoflagellatesKingdom: Protista

Division: Pyrrophyta “flame-colored algae” “fire algae” Class: Dinophyceae

Have both “plant” and “animal” characteristic.Unicellular biflagellate algaeMost photoautotrophs

Some are heterotrophic (predaceous or parasitic)Normally don’t occur below 50 m

Use flagella to stay up in water columnMarine and freshwater habitats

Mostly planktonicSome benthic species

Red tides (Dinoflagellate blooms)Neural toxinPopulation controlled by N, P, Fe, light

Geologic RangeSilurian-RecentCommon Permian – Recent as cysts.

AcritarchsKingdom: Protista

Division: Acritarcha

Organic-walled protists of uncertain phylogenetic, ecological placement that are the most common plankton preserved in Paleozoic rocks.

Most 20-150 mmSingle layer wall with central cavity.Known from Gunflint Chert (~2.0 b.y.)

Primary Consumer/ProtistaRadiolarians

Kingdom Protista Phylum Sarcodina

Class Actinopoda Subclass Radiolaria

Geologic range (Cambrian to Recent)Exclusively marine zooplanktonSpherical cells with pseudopodia (“false feet”)

Used to capture prey “micro-omnivores” Some symbiotic with zooxanthellae “aid in nutrition” Maintain bouyancy using fats or gases held within cell

or spines

Skeleton endoskeleton of Opal-AEven the spinesHard parts are never in direct contact with

seawater while they are alive.Porous skeleton, Why?

For diffusion to nutrients and wasteFor strength and light weight

Reproduction asexual mainly binary fission.Life span days to weeks to months

Ecology and DistributionMost diverse and abundant in equatorial

upwelling regions (up to 82,000/m3)Also abundant in polar upwelling regimes and

there abundant is diluted by the even more abundant diatoms.

Factor important in ooze deposition?1) Production2) Dissolution3) Dilution

Found from the surface down to 5000m alive, most in upper few hundred meters.

Greatest net accumulation is deep equatorial Pacific.

ForamsKingdom Protista

Phylum Sarcodina Class Rhizopoda

Order Foraminiferida “foramen” bearing Chambered protists in which the chambers are

connected by internal pore.

Geologic rangeBenthic forms: Cambrian to RecentPlanktonic forms: Triassic to Recent

Mainly marine, some brackish and freshwater species

Occur at all depths and all latitudes

Benthonic forams (1000’s of species)Sessile or vagrant using pseudopodiaLive in the interstitial water within the

sediment or on the sediment surface.Planktonic forams (~30 species)

Usually globose with inflated test. e.g., Globigerina

Nutrition “Micro-omnivores” like radiolariansUse pseudopodia to capture foodPhagocytosis “like ameba relatives”.Some symbiotic with zooxanthellaeAid to nutrition and calcification

SkeletonEndoskeleton or testMineralogically tests can vary.Three different types

1) Agglutinated forams, use cement to built a test of sand or silt-size grains .

2) Calcareous forams, mostly calcite either low or high-mg calcite.

3) Some very rare siliceous forams .

Diverse Test MorphologiesUniserial

Single series of chambersBiserial

Double row of chambersTriserial

Triple row of chambersCoiled

Planispiral Coiled in a single plane or axis

Trochospiral Translation along a vertical or second axis

Ecophenotypic variation (environmental phenotypes)

ReproductionShow alternation of sexual and asexual forms

Dimorphic test forms Gammont generation (N) – undergoes sexual

reproduction Schizont generation – undergoes asexual

reproductionAsexually produced forms have a large initial

chamber, but smaller overall test called “Megalospheric”

Sexually produced forms have a small initial chamber, but larger overall test called “Microspheric”

Some show brooding of young in shell interior“Commonly seen in fossil record”

Ecological usesBenthic forams are zoned according to

numerous variables including:SubstrateLightTemperatureOxygenSalinity

Benthic forams are excellent paleoenvironmental indicators in the fossil record.

Planktonic forams are excellent index fossils.

Evolution through Geologic TimeMost Paleozoic forms had aggulutinated test. Proteinaceous forms firstThen agglutinated testThen calcareous tests by increasing the amount of

cement over time. (Did not become common until Devonian time)

Paleozoic fusulinids (large forams) “rice grains”~5,000 species some up to 10 cm long!!!Go extinct end-Permian

Tertiary nummulites (5-20 mm) post-Eocene declineFound in the ancient Pyramids.

The fossil record suggest the “larger foraminifera” evolved at least four times during the Mesozoic and Cenozoic, each event representing the acquisition of symbiosis.

In each case the development took place in low paleolatitudes.

Four independent acquistions therefore not good time indicators.Example, of iterative evolution.