Taxonomy of commonly fossilised invertebrates

Although the phylogenetic classification of sub-vertebrate animals (both extinct and extant) remains a work-in-progress, the following taxonomy attempts to be useful by combining "both" traditional (old) "and" new (21st-century) paleozoological termonology.

So the paleobiologic systematics which follows is "not" intended to be all-inclusive or completely comprehensive. For practial reasons and relevancy, the below classification and annotations "emphasize invertebrates" that (a) are popularly collected as fossils and/or (b) no longer continue alive on this planet. Therefore, as a result, some phyla, classes, and orders of invertebrates are not listed. [ For superb anatomical illustrations and much-more comprehensive information, the aspiring paleozoologist should scan "Volume E" ("Archaeocyatha" / "Porifera") through "Volume V" ("Graptolithina"), published 1953 to 2006 (and continuing), of "the Treatise on Invertebrate Paleontology", long-edited by Raymond C. Moore and Roger L. Kaesler (Boulder, Colorado: Geological Society of America; and Lawrence, Kansas: University of Kansas Press). But be warned that some terms therein employed -- such as supersubphylum -- can be unnecessarily wordy or obstruse. Incidentally, "revised" volumes have been recently published regarding the sponges/archaeocyatha (2004, ISBN 08137 31313) and the brachiopods (2006, ISBN 0813731356). ]

If a non-vertebrate animal is mentioned below using its common, vernacular, "everyday" name, the creature is usually a living, present-day invertebrate. But if, on the other hand, a non-vertebrate is cited below by its scientific, taxonomic "genus" (in "italics"), then it is typically an extinct invertebrate, known only from the fossil record. [ The names of genera, orders, classes and phyla have been culled from dozens of sources, both current and decades-old. See the International Code of Zoological Nomenclature (ICZN), as well as "Volume 1" and "Volume 2" of "Grzimek's Animal Life Encyclopedia" (Farmington Hills, Michigan: Gale Group), edited by zoologists Michael Hutchin, Dennis A. Thorney and Sean F. Craig (2003). ]

Invertebrate clades that are (a) "very important" as fossils (for example, ostracods frequently used as index fossils), and/or (b) "very abundant" as fossils (for example, crinoids easily found in crinoidal limestone), [ For correspondingly-ancient ecosystems, see the "Treatise on Ecology and Paleoecology", "Volume 2: Paleoecology", edited for years by Harry S. Ladd (1957 / 1971), and published by both the Geological Society of America (Boulder, Colorado) and the Waverly Press (Washington, D.C.). ] are highlighted with a bracketed exclamation mark [ ! ] .

Invertebrate groups that (a) are now "substantially" extinct, and/or (b) contain a "large proportion" of extinct species, are followed by a dashed notation [ -- such as this ] . But invertebrate clades which are now "totally" -- that is, 100 percent -- "extinct" are designated with a bracketed dagger/cross [ † ] :

Domain of EUKARYOTA / EUKARYA

(eukaryotes / eukaryans / all cellular organisms bearing a central, organized nucleus with DNA)

*comprises "most" of the species of life which have been documented by biologists and paleontologists as either living or deceased

*includes a wide variety of single-celled protists, all algae, most plankton, most molds, the green plants, and "all" animal-related kingdoms
**but does "not" include the primal, sub-nuclear, prokaryotic domains of Archaea and Bacteria -- nor the enigmatic domain of Viruses

Sub-domain of OPISTHOKONTA

(opisthokonts / the animal-related kingdoms / the proto-spongal choanoflagellates, proto-fungal microsporidians, true fungi, and true animals

*comprises most life forms documented as either living or deceased
**excludes many molds, all one-celled protists (or protoctists), all algae, and all green plants

Kingdom of ANIMALIA / METAZOA

(metazoans / many-celled true animals / all invertebrates and vertebrates / multi-cellular creatures that grab and ingest their organic food)

*comprises most living and deceased species which have ever been recorded by paleontological and life scientists
**excludes all unicellular and fungal opisthokonts

=Sub-kingdom of PARAZOA=

(parazoans / typically-sessile, basal non-eumetazoans / the most-primitive animals / the simplest, colonial, attached, bottom-dwelling, marine invertebrates)

Phylum Archaeocyatha / Archeocyatha / Archaeocyathida / Archeocyathida / Pleospongia [†]

(cone-shaped archaeocyathids/archeocyathids / cup-shaped archaeocyathans/archeocyathans / reef-building pleosponges / calcareous "ancient-cups")

(includes fossil genera such "Archaeocyathus", "Cambrocyathus", "Atikonia", "Tumuliolynthus", "Kotuyicyathus", "Metaldetes", "Ajacicyathus" and "Paranacyathus")

(Archaeocyatha is sometimes classified as a class of Porifera below)

Phylum Porifera / Nuda / Spongia

(quintessential true sponges / marine, colonial, pore-bearing animals / organized collar-flagellates / poriferans; today mostly siliceous) -- "half" of all documented species of Porifera are fossils and extinct [ The rates of extinction for sponges and other phyla are derived from W. H. Easton, 1960, "Invertebrate Paleontology" (New York: Harper and Brothers) and various modern sources. ]

(Porifera may eventually be broken up into separate phyla)
*Sub-phylum Calcarea / Calcispongiae (primitive calcareous poriferans such as yellow lemon sponge, sphinctozoans, pharetronids, "Scypha", "Leucetta", "Gravestockia", "Grantia", "Astraeospongium", "Clathrina", "Lelapia", "Rhaphidonema", and "Girtyocoelia")
**Class Calcinea
**Class Calcaronea
**Class Stromatoporoidea / Stromatoporata / Stromatoporida / Spongliomorphida [†] (lime-layered stromatoporoids / reef-building stromatoporates / button-shaped stromatoporids / disc-shaped spongliomorphids; e.g., "Stromatopora, Aulacera, Stromatactis, Actinostroma, Discophyllum, Parallelopora" and "Amphipora")
**Class Heteractinida [†] (Paleozoic calcitic heteractinids such as "Eiffelia")
*Sub-phylum Silicea / Silicospongia (siliceous poriferans)
**Class Demospongea / Demospongiae (most living sponges hardened by opaline silica or spongin; for instance, horny sponge, bath sponge, stove-pipe sponge, yellow boring sponge, carnivorous sponge, bristle sponge, chaetids, lithistids, "Astroclera, Ceractinomorpha, Clionoides, Hindia, Ventriculites, Laosoiadia, Clionolithes, Tetractinella", and "Astylospongia")
**Class Hexactinellida / Hyalospongiae / Sclerospongiae (siliceous, deep-sea glass sponges, e.g. glassy-latticed Venus flower basket, bird's nest sponge, cloud sponge, "Hexactinella", "Hydroceras", "Dictyonina", "Brachiospongia", "Titusvillea", and "Rhizopoterion")

Phylum Placozoa

=Sub-kingdom of EUMETAZOA=

(eumetazoans / true metazoans / typically-mobile, multicellular animals)

(Eumetazoa contains "most" of the living and deceased species of recorded life, including "most" invertebrates (alive and extinct), as well as "all" vertebrate animals)

=Super-phylum of RADIATA=

(radiates / non-bilaterian eumetazoans)

Phylum Cnidaria / Coelenterata

(cnidarians / coelenterates)

*Class Hydrozoa (hydra or hydroid group)
**Subclass Stromatoporoidea [†] (lime-layered stromatoporoids)
**Subclass Conulata [†] (four-sided, pyramidal conularians)
*Class Anthozoa (corals / polyps)
**Subclass Receptaculidea [†] (receptaculites, a.k.a. sunflower corals)
**Subclass Octocorallia / Alcyonaria (soft corals and sea pens)
**Subclass Zoantharia [!] (sea anemones and most extant corals)
***Order Rugosa / Tetracoralla [†] [!] (wrinkled, horn-shaped tetracorals such as Petoskey coral, "Caninia" and "Heliophyllum")
***Order Tabulata / Schizocoralla [†] [!] (tabulate corals, for instance, "Favosites")
***Order Scleractinia / Hexacoralla [!] (stony corals such as brain coral, "Favia", "Meandrina", and most living corals)

=Super-phylum of LOPHOTROCHOZOA / PROTOSTOMIA # 1=

(lophotrochozoan bilaterians, such as flatworms, ribbon worms, lophophorates, and molluscs)

Phylum Bryozoa / Ectoprocta / Polyzoa

(bryozoans / moss animals) -- "half" of all documented species of Bryozoa are fossils "and" extinct [ For bryozoans and brachiopods, the same footnote as above. ]
*Class Stenolaemata / Gymnolaemata [!] (mostly marine, calcareous bryozoans)
**Order Cheilostomata [!] (living, rimmed-mouthed moss animals)
**Order Cyclostomata (uncontracted, round-mouthed bryozoans including fossil "Stomatopora")
**Order Cystoporata [†] (extinct, minor group of moss animals)
**Order Trepostomata [†] [!] (changed-mouthed bryozoans such as extinct "Constellaria" and "Monticulipora")
**Order Cryptostomata [†] [!] (round hidden-mouthed bryozoans such as "Archimedes", "Fenestrellina" and "Rhombopora")
**Order Ctenostomata [†] (uncommon, comb-mouthed bryozoans)
**Order Phylactolaemata (living, fresh-water bryozoans)

Phylum Brachiopoda

(lampshells, brachiopods or "brachs," not to be confused with the hard-shelled marine mollusks below) -- "99 percent" of all documented species of Brachiopoda are now extinct

*Subphylum Linguliformea (inarticulate atremates, such as "living fossil" "Lingula") -- but mostly extinct
*Subphylum Craniiformea (inarticulate neotremates, such as extant "Crania") -- but mostly extinct
*Subphylum Rhynchonelliformea [!] (articulate brachiopods with hinged valves; includes most extinct "and" living brachs)
**Class Rhynchonellata [!]
***Order Orthida [†] [!] (orthid brachs such as fossil "Orthis")
***Order Pentamerida [†] (pentamerid brachs such as "Conchidium")
***Order Rhynchonellida [!] (rhynchonellid brachs such as fossils "Rhynchotrema" and "Rhynchonella")
***Order Spiriferida [†] [!] (spiriferid brachs)
****Suborder Spiriferinida [†] [!] (spiriferid brachs such as "Spirifer" and "Eospirifer")
****Suborder Atrypida [†] [!] (atrypid brachs such as "Atrypa")
***Order Terebratulida [!] (most living brachiopods; includes fossil "Dielasma")
**Class Strophomenata [†] [!] (so-called petrified butterflies)
***Order Strophomenida [†] [!] (strophomenid brachs)
***Order Productida [†] [!] (spiny or productid brachs)
****Suborder Chonetidina [†] [!]
****Suborder Productidina [†] [!]

Phylum Annelida

(segmented worms such as earthworms and leeches)

*Class Polychaeta (marine annelids / polychaetes)
**Order Scolecodonta [!] (mostly chitinous jaws of scolecodonts)

Phylum Mollusca

(molluscs or mollusks, not to be confused with the hard-shelled marine brachiopods above)

*Class Monoplacophora (extinct, except for "living fossil" Neopilina)
*Class Bivalvia / Pelecypoda (bivalves / pelecypods) -- "half" of all documented species of Bivalvia are fossils "and" extinct [ For bivalves and cephalopods (both mollusks), see the above notation. ]
**Subclass Lamellibranchia [!] (clams, oysters, mussels and scallops)
*Class Gastropoda (gastropods / snail group)
**Subclass Prosobranchia (marine snails and conches)
**Subclass Opisthobranchia (sea slugs)
**Subclass Pulmonata (land snails)
*Class Cephalopoda (cephalopods) -- "97 percent" of all documented species of Cephalopoda are now extinct
**Subclass Nautiloidea (mostly extinct, but includes "living fossil" "Nautilus")
***Order Orthocerida [†] [!] (long, straight-shelled nautiloids)
**Subclass Ammonoidea [†] [!] (generally coiled-shelled ammonoids)
***Agoniatitic (agoniatites) [†]
***Goniatitic (goniatites) [†] [!] (ammonoids with simple sutures)
***Ceratitic (ceratites) [†]
***Ammonitic [†] [!] (the true ammonites, bearing complex sutures)
**Subclass Coleoidea (includes the living squid, cuttlefish, and octopus)
***Order Belemnoidea [†] (extinct orthoconic belemnoids)

=Super-phylum of ECDYSOZOA / PROTOSTOMIA # 2=

(ecdysozoans, such as nematodes, horsehair worms, and molting bilaterians / panarthropods))

Phylum Tardigrada

(panarthropodic water bears)

Phylum Onychophora

(panarthropodic velvet worms, including proto-arthropodic fossils of "Arthropleura" and "Aysheaia")

Phylum Arthropoda

(arthropods; jointed legged creatures with an exoskeleton)

*Subphylum Crustacea (crustaceans)
**Class Ostracoda (ostracods)
**Class Malacostraca (true crabs, lobster and most shrimp)
**Class Branchiopoda (brine shrimp)
***Order Norostraca
**Class Cirripedia (barnacles)
**Class Arachnoidea
*Subphylum Trilobitomorpha [†] (extinct trilobite group)
**Class Trilobita [†] (the armored trilobites)
*Subphylum Hexapoda
**Class Insecta (insects, best preserved in amber)
*Subphylum Chelicerata
**Class Arachnida (spiders, best preserved in amber)
**Class Merostomata ("living fossil" horseshoe crab and extinct eurypterid)
*Subphylum Myriapoda
**Class Diplopoda
**Class Chilopoda

Super-phylum of "'DEUTEROSTOMIA / ENTEROCOELOMATA

(second-mouthed bilaterians called deuterostomians, such as chordates and echinoderms)

Phylum Echinodermata

(echinoderms) -- "72 percent" of all documented species of Echinodermata are fossils "and" extinct [ For the echinoderms, see the above footnote regarding W. E. Easton, 1960, "Invertebrate Paleontology", and other sources. ]

*Subphylum Crinozoa (sessile echinoderms) -- "91 percent" of all documented species of Crinozoa are now extinct
**Class Crinoidea (crinoids / sea lilies) -- See Crinozoa above
*Subphylum Blastozoa [†] (extinct blastoids)
**Class Diploporita
**Class Rhombifera
*Subphylum Echinozoa (mobile echinoderms) -- "89 percent" of all documented species of Echinozoa are now extinct
**Class Echinoidea (echinoids or sea urchins) -- See Echinozoa above
*Subphylum Asterozoa
**Class Asteroidea (sea stars / starfish)
**Class Ophiuroidea

Phylum Hemichordata

(hemichordates such as extant acorn worms) -- "Less than half" of the documented species of Hemichordata are fossils "and" extinct

*Class Graptoloidea [†] (extinct graptolites)
**Order Dendroidea [†]
**Order Graptoloidea [†]
***Suborder Didymograptina [†]
***Suborder Diplograptina [†]
***Suborder Monograptina [†]

Phylum Chordata

("both" invertebrate "and" vertebrate chordates; animals possessing a notochord)

Invertebrate subphyla

*Subphylum Urochordata (invertebrate tunicate such as sea squirts)

*Subphylum Cephalochordata (invertebrate lancelets)

ubphylum Vertebrata

*(vertebrates such as hagfishes, lampreys, conodonts [†] , ostracoderms [†] , placoderms [†] , sharks, ray-finned fishes, lobe-finned fishes, amphibians, reptiles, dinosaurs [†] , birds and mammals)

Footnotes

ee also

*Invertebrate palæontology