Publication of the decades-long Treatise on Invertebrate Paleontology is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post-Paleozoic eracaenogastropods (a molluscan group including the whelk and periwinkle). Furthermore, every so often, previously published volumes of the Treatise are revised.
Evolution of the project
Raymond C. Moore, the project's founder and first editor, originally envisioned this Treatise in invertebrate paleontology as comprising just three large volumes, and totaling only three thousand pages.
The project began with work on a few, mostly slim volumes in which a single senior specialist in a distinct field of invertebrate paleozoology would summarize one particular group. As a result, each publication became a comprehensive compilation of everything known at that time for each group. Examples of this stage of the project are Part G. Bryozoa, by Ray S. Bassler (the first volume, published in 1953), and Part P. Arthropoda Part 2, the Chelicerata by Alexander Petrunkevitch (1955/1956).
Around 1959 or 1960, as more and larger invertebrate groups were being addressed, the incompleteness of the then-current state of affairs became apparent. So several senior editors of the Treatise started major research programs to fill in the evident gaps. Consequently, the succeeding volumes, while still maintaining the original format, began to change from being a set of single-authored compilations into being major research projects in their own right. Newer volumes had a committee and a chief editor for each volume, with yet other authors and researchers assigned particular sections. Museum collections that had not been previously described were studied; and sometimes new major taxonomic families—and even orders—had to be described. More attention was given to transitional fossils and evolutionaryradiation—eventually producing a much-more complete encyclopedia of invertebrate paleontology.
But even in the second set of volumes, the various taxa were still described and organized in a classical Linnaean sense. The more-recent volumes began to introduce phylogenetic and cladistic ideas, along with new developments and discoveries in fields such as biogeography, molecular phylogeny, paleobiology, and organic chemistry, so that the current edition of Brachiopoda (1997 to 2002) is classified according to a cladistic arrangement, with three subphyla and a large number of classes replacing the original two classes of Articulata and Inarticulata.
All these discoveries led to revisions and additional volumes. Even those taxa already covered were expanded: Books such as those regarding the Cnidaria (vol. F), the Brachiopoda (vol. H) and the Trilobita (vol. O) each went from one modest publication to three large volumes. And yet another volume regarding the brachiopods (number five) was published in 2006.
From the beginning, the character of the Treatise volumes has followed and further developed the pattern of the classic Invertebrate Paleontology written by Moore, Lalicker and Fischer (1953).
Following their lead, the Treatise includes in a typical article (a) a description of the basic anatomy of the modern members of each invertebrate group, (b) distinctive features of the fossils, (c) a comprehensive illustrated glossary of terms, (d) a short discussion of the evolutionary history of the group, (e) a stratigraphic range chart, done at the level of the major subdivision (lower, middle and upper) of each Geologic period.
This is followed by (f) a listing and technical description of every known genus, along with (g) geographic distribution (usually by continent only, but occasionally by country) and (h) stratigraphic range.
Next come (i) one or two representative species illustrated by line drawings (in the early volumes) or by black-and-white photographs (in subsequent volumes), each accompanied by an appropriate reference for that genus. Furthermore, each Treatise article includes (j) the date, authorship, and scientific history of the taxa.
Finally, there is (k) a comprehensive bibliography and list of references. Not only that, but the more recent volumes and revisions also include (l) new fossil and phylogenetic discoveries, (m) advances in numerical and cladistic methods, (n) analysis of the group's genome, (o) its molecular phylogeny, and so on.
List of its volumes
The following is an annotated list of the volumes already published (1953 to 2007) or volumes currently being prepared:
Introduction (A) and sub-metazoan Protista (B, C & D)
Part D. Protista / Protoctista, Volume 3: Protozoa (Chiefly Radiolaria & Tintinnina), xii + 195 p., 92 fig., 1954. ISBN0-8137-3004-X. The original volume is out of print but is available here. [5]
Part E, Revised. Porifera, Volumes 4 & 5: Hypercalcified Porifera, Paleozoic Stromatoporoidea & Archaeocyatha, liii + 1223 p., 665 figs., 2015, available here. ISBN978-0-9903621-2-8.[10]
Cnidaria or Coelenterata (F)
Part F.Coelenterata / Cnidaria, xvii + 498 p., 358 fig., 1956. ISBN0-8137-3006-6. The original volume is out-of-print, but is available here. --- Part F refers to the corals and other cnidarians. Coelenterata is an outdated term for two now separated phyla, Cnidaria and Ctenophora (comb jellies).[11]
Part G.Bryozoa, xii + 253 p., 175 fig., 1953. ISBN0-8137-3007-4. The original volume is out-of-print, but is available here. --- Part G refers to bryozoans, colonial animals also known as ectoprocts or moss animals.[13]
(Part G, Revised. Bryozoa --- additional volumes in preparation).
Brachiopoda (H)
Part H.Brachiopoda, vol. 1 & 2, xxxii + 927 p., 746 fig., 1965. ISBN0-8137-3008-2. The original volume is out-of-print, but is available here. --- Part H refers to brachiopods, shelled animals including living lamp shells.[15]
Part H, Revised. Brachiopoda, Volume 1: Introduction, xx + 539 p., 417 fig., 40 tables, 1997, available here. ISBN0-8137-3108-9.[16]
(Part J, Mollusca 2: Paleozoic Gastropoda --- volume in preparation).
Part K. Mollusca 3: Cephalopoda General Features, Endoceratoidea, Actinoceratoidea, Nautiloidea, & Bactritoidea, xxviii + 519 p., 361 fig., 1964. ISBN0-8137-3011-2. The original volume is out of print, but is available here. --- Parts K and L refer to cephalopods with external shells, including ammonites and Nautilus-like creatures.[22]
(Part K, Revised. Mollusca 3: Nautiloidea --- volume in preparation).
Part L. Mollusca 4: Ammonoidea, xxii + 490 p., 558 fig., 1957. ISBN0-8137-3012-0. The original volume is out-of-print, but is available here.[23]
Part L, Revised. Mollusca 4, Volume 4: Cretaceous Ammonoidea, xx + 362 p., 216 fig., 1995 / 1996, available here. ISBN0-8137-3112-7.[25]
(Part L, Revised. Mollusca 4: Paleozoic to Jurassic Ammonoidea --- additional volumes in preparation).
(Part M. Mollusca 5: Coleoidea --- volume in preparation. --- Part M includes coleoids (cephalopods without external shells) such as squids, cuttlefish, and extinct belemnoids).
Part N. Mollusca 6: Bivalvia, Volumes 1 and 2 (of 3), xxxvii + 952 p., 613 fig., 1969. ISBN0-8137-3014-7. The original volume is out of print, but is available here. --- Part N refers to clams, oysters, scallops, mussels and other fossilized bivalves or pelecypods.[26]
(Part Q, Revised. Arthropoda 3 --- in preparation).
Part R. Arthropoda 4, Volumes 1 and 2: Crustacea (exclusive of Ostracoda), Myriapoda, & Hexapoda, xxxvi + 651 p., 397 fig., 1969. ISBN0-8137-3018-X. The original volume is out-of-print, but is available here.[32]
Part R. Arthropoda 4, Volumes 3 and 4: Hexapoda, xxii + 655 p., 265 fig., 1992. ISBN0-8137-3019-8. The original volume is out-of-print, but is available here.[33]
(Part R, Revised. Arthropoda 4 --- in preparation).
Echinodermata (S, T & U)
Part S.Echinodermata 1, Volumes 1 and 2: Echinodermata General Features, Homalozoa, Crinozoa (exclusive of Crinoidea), xxx + 650 p., 400 fig., 1967 / 1968. ISBN0-8137-3020-1. The original volume is out-of-print, but is available here. ---- Part S refers to primitive sessile echinoderms.[34]
Part T. Echinodermata 2, Volumes 1-3: Crinoidea, xxxviii + 1,027 p., 619 fig., 1978. ISBN0-8137-3021-X. The original volume is out-of-print, but is available here. ---- Part T refers to crinoids, a group of echinoderms including living sea lilies.[35]
Part T, Revised. Echinodermata 2, Volume 3: Crinoidea, xxix + 261 p., 112 fig., 2011, and is available here. ISBN978-0-9833599-1-3.[36]
Part V, Revised. Graptolithina, with sections on Enteropneusta & Pterobranchia, xxxii + 163 p., 109 fig., 1970 / 1971, and is available here. ISBN0-8137-3123-2.[39]
Part W, Revised. Miscellanea: Trace Fossils and problematica, xxi + 269 p., 110 fig., 1975. The original volume is out-of-print, but is available here. ISBN0-8137-3027-9.[41]
(Part W, Revised. Trace Fossils --- in preparation)
^Paleontological Institute. "Part B, Protista 1, vol. 2". Treatise on Invertebrate Paleontology. Archived from the original on 9 October 2016. Retrieved 5 December 2013.
Arkell, W.J.; Kummel, B.; Wright, C.W. (1957). Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Lawrence, Kansas: Geological Society of America and University of Kansas Press.
Ladd, Harry S., editor, (1957 / 1971), Treatise on Ecology and Paleoecology, Volume 2: Paleoecology. Boulder, Colorado: Geological Society of America; and Washington, D.C. : Waverly Press.