Phylum Ctenophora + Cnidaria

Leonie Koch (10Jahre) 2013

Polyphyletic Origin of Sponges?

Hexac

tinell

ida

Biofilm/Protozoa Ancestral SymbiosisBasic Sponge Organisation

Protozoa Outgroup

(Choanoflagellata)

Demospongiae

Ancestral „DemoHex“„Demospongic Acids“

coincidencies in 18s rDNA

DemoHex Outgroup

Cten

opho

ra

Ancestral „CtenoCalc“No „Demospongic Acids“similarities in 18sRNA

Calcarea

COOH(CH2)n

‘DEMOSPONGIC ACIDS’ (C24-C32)

Borchiellini et al. 2001(18s rDNA)

Symbiotic Bacteria& few Archaea

Symbiotic Archaea& few Bacteria

JR 2005G GZ

?

Journal of Heredity 2014:105(1):1–18doi:10.1093/jhered/est084

Placozoa: Only one species:

Trichoplax adhaerens

PoriferaPorifera

CnidariaCnidaria

CtenophoraCtenophorametazoametazoa

parazoaparazoa

•• mesodermallymesodermally derived musclesderived muscles•• acetylcholineacetylcholine--based nervous systembased nervous system

eumetazoaeumetazoa

triploblastictriploblastic

diploblasticdiploblastic

PoriferaPorifera

MetazoaMetazoa

•• diploblasticdiploblastic -- muscle tissue associated muscle tissue associated with with gastrodermisgastrodermis or epidermisor epidermis

•• cnidocytescnidocytes

CnidariaCnidaria

EumetazoaEumetazoa

diploblasticdiploblastic

Ctenophora (Comb Jellies)

Ryan et al Science, 243, 2013

Ryan et al Science, 243, 2013

Ryan et al Science, 243, 2013

Ctenophores and CnidariansMay be known as far back as Precambrian “Ediacaran organisms” Hydroskeletons – Pneus!

Ctenophores and CnidariansMay be known as far back as Precambrian “Ediacaran organisms” Hydroskeletons – Pneus!

Shu DG, Morris SC, Han J, Li Y, Zhang XL, Hua H, Zhang ZF, Liu JN, Guo JF, Yao Y, Yasui K (2006) Lower Cambrian vendobionts from china and early diploblastevolution. Science 312(5774):731-4

Stromatoveris

Ctenophores –comb jelly fish

Maotianoascus octonarius from Lower Cambrian Maotianshan shale at Mt. Maotian, Chengjiang, Yunnan. (Scale bars, 10 mm.) (A and B) Part and counterpart of the holotype in this species. (C) A paratype specimen of this species. ST, statolith; CR, comb row; MC, meridional canal; SK, skirt-like possible oral lobe.

Chen et al. 10.1073/pnas.0701246104.

Ctenophores and CnidariansMay be known as far back as Precambrian “Ediacaran organisms” Hydroskeletons – Pneus!

VINN O. & ZATOŃ M. (2012).- Inconsistencies in proposed annelid affinities of early biomineralizedorganism Cloudina(Ediacaran): structural and ontogenetic evidences.- Carnets de Géologie [Notebooks on Geology], Brest, Article 2012/03 (CG2012_A03), p. 39-47

The way of asexual reproduction in Cloudina resembles more that of cnidarians. The presence of a closed tube origin (base) in Cloudina is also compatible with the hypothesis of an animal of cnidarian grade.

Velella velella - By the wind sailorChondrophore – Porpitid, Hydrozoan

Ovatoscutum concentricusEdiacaran age

Corals (class Anthozoa of the phyllum Cnidaria or Coelenterata) are an extant group of organisms related to jellyfish and sea anemones. This group possesses the following characteristics:

1) Radially symmetric body plan (may be slightly modified)2) Aquatic3) Mostly marine (a few freshwater forms - e.g. hydra)4) 2 Body layers - ectoderm & endoderm (no mesoderm)5) Tentaculate6) Cnidoblasts - stinging cells lodged in the ectoderm

Cnidarians come in two basic forms:

1) Free swimming medusae

Body stalk

Tentacle

2) Attached polyps.

Cnidarian Body Plans

Cnidaria (Coelenterata or Corals)

Two forms:

Polyps and Medusa

Polyps – asexual

Medusa - sexual

Movement

• The cnidarian body is capable of some kind of coordinated movement• Both the epidermis and the gastrodermis possess nerve cells arranged in a loose network - nerve net (plexus), which innervate primitively developed muscle fibers that extend from the epidermal and gastrodermal cells• Stimulus in one part will spread across the whole body via the network

Nutrition

• Cnidarians are carnivores with hydras and corals consuming plankton and some of the sea anenomes consuming small fishes

• They use they tentacles to capture prey and direct it toward the mouth so that it can be digested in the gastrovascular cavity via secretions from gland cells (extracellular digestion); some food is phagocytized by special cells and digestion occurs intracellularly

• The gastrovascular cavity exists as 1 opening for food intake and the elimination of waste

• There is no system of internal transport, gas exchange or excretion; all these processes take place via diffusion

Stinging Organelles

• Prey capture is enhanced by use of specialized stinging cells called cnidocytes located in the outer epidermis.• Each cnidocyte has a modified cilium -cnidocil, and is armed with a stinging structure called a nematocyst.• The undischarged nematocyst is composed of a long coiled thread • When triggered to release, either by touch or chemosensation, the nematocyst is released from the cnidocyte and the coiled thread is everted• Some nematocysts function to entangle the prey; others harpoon prey and inject a paralyzing toxin

Cnidaria (Coelenterata or Corals)Stinging cellsCnidocytes

Cnidaria (Coelenterata or Corals)Stinging cells or Cnidocytes

Box jellyfish, or sea wasp (Chironex fleckeri).

Reproduction

• One of the most amazing adaptations is the ability of some cnidarians to regenerate lost parts or even a complete body• Asexual reproduction is common with new individuals being produced by budding• Sea anenomes engage in a form of asexual reproduction called pedal laceration• Cnidariand are dioecious• Fertilization is external, with the zygote becoming a elongated, ciliated, radiallysymmetrical larva - planula larva

Planula larva

Classification:

Phylum: Cnidaria (or Coelenterata)

Class: Hydrozoa(Hydroids – includes sessile colonial reef-building forms with a calcareous skeleton, and large complex, floating colonies, such as ‘Potuguese man o’ war’)Precambrian-Recent)

Class: Scyphozoa(Jellyfish – solitary medusoids)(Precambrian-Recent)

Class: Anthozoa(Corals and anemones – solitary and colonial polyps)(Precambrian-Recent)

Class Hydrozoa• Includes the solitary freshwater hydra; most are colonial and marine • Typical life cycle includes both asexual polyps and sexual medusa stages; however, freshwater hydras and some marine hydroids do not have a medusa stage

Solitary Hydras• Freshwater hydras are found in ponds and streams occurring on the underside of vegetation• Most possess a pedal disc, mouth, hypostome surrounded by 6-10 tenetacles• Mouth opens to the gastrovascular cavity • The life cycle is simple: eggs and sperm are shed into the water and form fertilized eggs; planula is by passed with eggs hatching into young hydras • Asexual reproduction via budding

Colonial Hydrozoans - e.g., Obelia

• Possess a skeleton of chiton that is secreted by the epidermis• All polyps in the colony are usually interconnected• Two different kinds of individuals that comprise the colony: feeding polyps or gastrozooids (C) and reproductive polyps or gonozooids(B)

Life Cycle of Obelia• Gonozooids release free swimming medusae• Zygotes become planula larvae, which eventually settle to become polyp colonies

• The medusae of hydroids are smaller than those of jellyfishes (C. Scyphozoa)• Also, the margin of the bell projects inward forming a shelf-like velum

Other Hydrozoans

Portuguese man-of-war:Single gas-filled float with tentaclesTentacles house the polyps and modified medusae of the colony

Heterastridium conglobatumMiddle Norian, Bad Aussee

Class Scyphozoa

Jellyfish

• The medusae are large and contain massive amounts of mesoglea• The differ from the hydrozoanmedusa in that the lack a velum•Possess four gastric pouches lined with nematocysts; these are connected with the mouth an the gastrovascular system

• Gametes develop in gastrodermis of gastric pouches; eggs and sperm are shed through mouth• Fertilized eggs develop into a planula larva; settles on substrate and develops into a polyp - scyphistoma• Scyphistoma produces a series of polyps by budding - strobila• The polyps undergo differentiation and are released from the strobila as free swimming ephyra• Ephyra matures into an adult jellyfish

Scyphozoan Life Cycle - Aurelia

Fossil medusa

Rhizostomites admirandusTithonian, PfalzpaintLithographic Limestone

NarcomedusaMarjum Formation (Utah) Middle Cambrian

Krukowski Quarry, Mount Simon Sandstone Outlier, Mosinee,WisconsinMiddle Cambrian

Cnidaria: Corals

Class Anthozoa cont.

• Solitary anthozoans include sea anemones• Most anthozoans are colonial (e.g. corals) and secrete external skeletons composed of calcium carbonate.• Corals obtain much of their energy from microscopic photosynthetic green algae (zooxanthellae) or dinoflagellates that live symbiotically inside the cells of the coral

Septal insertion in scleractinian corals.

The protocorallite possess 6 septa as in rugosans.

Subsequent septa are inserted in cycles of 6 between all previous septa.

Thus cycles of 6+6+12+24…

Scleractinina

Anis-RecentAragonitic Skeleton

With exceptions!

Corals and their kin through time. The verticallength of the spindle diagrams indicates thetemporal extent of the three major orders of calcified corals, and the thickness indicates theirrelative diversity and abundance. The colored lineat the base of the Triassic indicates the coral gap. The vertical bar to the right represents soft-bodiedforms, for which the fossil record is very poor ornonexistent. The figure is therefore not meant to imply a continuous lineage for any group nor that all of the soft-bodied forms are one another's closestrelatives.

Asterisks indicate occurrences of calcifiedscleractiniamorphs. Right arrows suggest times of loss and left arrows times of gain of calcifiedskeletons, which may have occurred several timesduring geologic time. [Modified from (9)]

Science 9 March 2001:Vol. 291. no. 5510, pp. 1913 - 1914DOI: 10.1126/science.1056632Prev | Table of Contents | Next PerspectivesPALEONTOLOGY AND EVOLUTION:The Origins of Modern CoralsGeorge D. Stanley Jr. and Daphne G. Fautin*

Scleractiniamorphs

A sketch of the septal plan of an Ordovician kilbuchophyllid coral. Each number indicates the timing of the addition of a setof septa. The septal plan appears hexameral and is very much like that of Mesozoic scleractinians. (After Scrutton and Clarkson, 1991.)

Paleozoic possible ancestors of Scleratinia

Various types of scleractinian microstructure recognized in most Mesozoic corals. Different types of microstructure are illustrated from enlarged views of the septa and walls of scleractinians, some of which provide enlarged details. e.w.=epithecal walls; f.s.=flange-likestructures; m.l.=midseptal lines; P=pores; PE=pennular structures; s.s.=septal spines; T=thicktrabeculae. (From Roniewicz, 1996. Reproduced with permission of the PaleontologicalSociety.

Scleractinia:

• Range Triassic to Recent

•Septa, tabulae and dissepiments present

•Septa inserted in cycles of 6 (sometimes called ‘hexacorals’)

• Colonial and solitary forms

• Build aragonite skeletons, although generally a lighter construction

• Important reef builders

• Can broadly be divided ecologically into two sub groups:

Recent ‘brain’ coral

HERMATYPIC

(Reef making with photosynthesising algal symbionts in their tissues to boost energy production)

AHERMATYPIC

(Non reef making)

Cnidaria: Anenomes

http://www.coralscience.org/articles/ecology/Cold%20water%20reefs/Lophelia%20pertusa.jpg

Lophelia pertusaAhermatypic deep water coral

Searching for the ancestors. (Left) A fossil scleractinian coral of Triassic age. (Middle) The calcified skeleton of a modern scleractinian. (Right) A living corallimorpharian polyp, a soft-bodied species. Were the ancestors and some descendants of living corals soft-bodied·CREDIT: RIGHT IMAGE/JOEL ELLIOTT

Astrangia – a modern reef-building scleractinian

Thecosmilia – a fasciculate scleractinian

A massive scleractinian coral with corallites joined by connecting tissue

A scleractinian coral with a meandroid colony

Morphology of the modern aragonite Desmophyllum sp. and the Late Cretaceous calcitic Coelosmilia sp. (A and B) Desmophyllum sp.

Relatively smooth septa, a thick septothecal wall, and a lack of pali are typical features of this solitary, azooxanthellate scleractinian coral. (Cto H) Coelosmilia sp. resembles Desmophyllum sp. in all morphological aspects. Distal [(A), (C), (E), and (G)] and lateral [(B), (D), (F), and (H)] views are shown. Scale bar, 10 mm.

A Cretaceous Scleractinian Coral with a Calcitic Skeleton

Jaros aw Stolarski,1* Anders Meibom,2 Rados aw Przenios o,3 Maciej Mazur

Science 2007, 318, 92-94

Calcite Scleractinians

Octocorallia – Gorgonians, Pennatulacea etc.

ScleritesMg-Calcite

PALEOZOIC Corals

Rugosa (Rugose or Horn Corals)Ranged from Ordovician to PermianNot major reef formers, colonizersUsually solitaryAbundant in Silurian and Devonian reefs

Mg-calcitic Biomineral

Corals and their kin through time. The vertical length of the spindlediagrams indicates the temporal extent of the three major orders of calcified corals, and the thickness indicates their relative diversity and abundance. The colored line at the base of the Triassic indicates the coralgap. The vertical bar to the right represents soft-bodied forms, for whichthe fossil record is very poor or nonexistent. The figure is therefore notmeant to imply a continuous lineage for any group nor that all of the soft-bodied forms are one another's closest relatives. Asterisks indicateoccurrences of calcified scleractiniamorphs. Right arrows suggest times of loss and left arrows times of gain of calcified skeletons, which may haveoccurred several times during geologic time. [Modified from (9)]

Science 9 March 2001:Vol. 291. no. 5510, pp. 1913 - 1914DOI: 10.1126/science.1056632Prev | Table of Contents | Next PerspectivesPALEONTOLOGY AND EVOLUTION:The Origins of Modern CoralsGeorge D. Stanley Jr. and Daphne G. Fautin*

Early Cambrian Coral Flindersipora

Rugosa (Rugose or Horn Corals)

Septal insertion in rugose corals.

The protocorallite possess 6 septa –cardinal (C), counter cardinal (K), 2 counter laterals (CL) and 2 alar (A).

Subsequent septa are inserted at 4 points – on the cardinal side of the counter lateral septa, and on the cardinal side of the alarsepta.

Solitary corals.

Solitary corals live alone. They display a range of structural morphologies (Fig 3).Zaphrentites (Fig 2) is a typical small solitary ‘horn’ shaped coral. The main structural features are labelled.

calice

cardinal fossula

epitheca

tabulae

septae

Classification for solitary corals is generally based on:

• Vertical structures: Septae and axial structure

• Horizontal structures: Tabulae

Fig 2: Zaphrentites sp. (Carboniferous)

Rugosa (Rugose or Horn Corals)

Fig 3; Some morphology of solitary corals, particularly Rugosa. (a) - (i) Types of corallites: (a) ceratoid (horn shaped - continuously expanding with a curved axis. Note - if the axis remains straight the term conical applies), (b) cylindrical, (c) scolecoid (parallel sided with a sinuous axis), (d) trochoid, (e) patellate, (f) turbinate, (g) discoid, (h) calceoloid, (i) pyramidal.

(j) and (k) General morphology of corallites: (1) corallite, (2) calyx, (3) septum, (4) cardinal fossula, (5) counter septum, (6) counter-lateral septum, (7) epitheca, (8) dissepimentarium, (9) dissepiment, (10) tabula, (11) axial boss, (12) major septum, (13) minor septum, (14) columella, (15) stereozone. Modified from Moore, Lalicker & Fischer (1952)

Colonial corals.

Colonial corals involve groups of corallites which are integrated and interdependent to various degrees (depending on genus - note the difference between dendroid and meandroid morphology below).

A colony is one in which functional modular units are budded asexually (i.e. genetically uniform). Lithostrotion (Fig 4) is a typical lower Carboniferous colonial coral.

Fig 4: Detail of some corallites belonging to Lithostrotionsp. (Lower Carboniferous) a massive colonial coral.

Top view

dissipiments

columella

2 basic types of colonial coral:

1) Open Branching forms (fasciculate) (Fig 5)

2) Massive forms (compound) (Fig 6)

2 basic types of colonial coral:

1) Open Branching forms (fasciculate) (Fig 5)

2) Massive forms (compound) (Fig 6)

Fig 5Dendroid Phaceloid

Fig 5: Lateral and cross sectional views of two types of fasciculate(open branching) morphology in colonial corals:

Dendroid - irregular branching.

Phaceloid - corallites more or less parallel

Fig 6

Fig 6: Cross sectional views of six types of massive colonial corals:

Cerioid - each corallite retains its wall.

Astreoid - Walls are wholly or partially lost. Septa unreduced.

Thamnasterioid - septa of neighbouring corallites confluent (shared)

Aphroid - Septa reduced. Corallites united by dissepiments

Hydnophoroid - corallites centres arranged around protuberances; walls incomplete. No real intervening colonial skeleton.

Meandroid - corallites meandering, bounded by walls. Intervening colonial skeleton absent.

Classification of corals.

There are three important suborders or groupings of corals to remember.

Acervularia (Silurian)

Rugosa:

• Range Lower Ordovician to Permian

• Possess conspicuous septa and usually tabulae and dissepiments

• Septa inserted at 4 points around corallite (sometimes called ‘tetracorals’)

• Colonial and solitary forms

• Built calcite skeletons

Hexagonaria – a colonial rugosan

Caninia – a solitary rugosan

Tabulata:

• Range Lower Ordovician to Permian

• Septa absent or only very weakly developed

• Tabulae well developed

• Colonial forms only

•Connections between corallites

• Built calcite skeletons

Syringopora sp. (Carboniferous)

Lateral view Cross sectional view

HeterocoralliaUpper Devonian-Carboniferous

Some different types of tabulate coral colonies.

Halysites – a tabulate coral which forms a chain-like colony