A new classification of the Brachiopoda is proposed to take into account recent advances in our understanding of the anatomy, shell morphology, ontogeny and phylogeny of the phylum. The use of phylogenetic analysis to help rationalize this new information did not obviate the dilemma facing all previous classifications of how best to reconcile fossil and living data. Over 95% of all recognized genera are founded on extinct species, with the greatest diversity occurring in Cambro-Ordovician times when all but two of the 26 major groups constituting the phylum first appeared. Only five of these groups survive to the present day, albeit as well dispersed representatives of the early diversity. To com pare phylogenies extrapolated from these data, phylogenetic analyses of Recent and Cambro-Ordovician groups were conducted independently by using 55 biological characters for the former group and 69 morphological (and inferred anatomical) features for the latter; only 12 characters were common to both exercises. The cladogram derived for seven Recent suprafamilial taxa, with Phoronis and cyclostome and ctenostome bryozoans as outgroups, is virtually the same as that being obtained by studies of the brachiopod genome. It is also largely compatible with the cladogram for 33 Cambro-Ordovician suprafamilial taxa with Phoronis as outgroup. This cladogram has, in turn, been subjected to stratocladistic tests and has been shown to be consistent with the stratigraphic records of the taxa analysed. A reconciliation of the genealogies derived from the Recent and Cambro-Ordovician data, represented by 14 taxa and clades (with Phoronis as outgroup), was effected by using the 19 synapomorphies characterizing these groups. The resultant cladogram shows living organophosphatic-shelled lingulids (and discinids) as a sister group to a clade of all other living brachiopods. This clade, however, includes the extinct organophosphatic-shelled paterinids and the organocalcitic-shelled craniids. The inclusion of the craniids, in particular, is a cladistic compromise that is inconsistent with genetic and some anatomical and morphological evidence. It was therefore decided to accommodate these inconsistencies by dividing the Brachiopoda into three subphyla, each typified by Recent species with early Palaeozoic ancestors and defined by easily identifiable synapomorphies. The inarticulated Linguliformea, consisting of two classes (Lingulata and Paterinata), is characterized by an organophosphatic shell with a stratiform secondary layer and by planktotrophic larvae. Its modern representatives are the lingulids and discinids. The inarticulated Craniiformea is primarily distinguished by an organocarbonate shell with a laminar secondary layer and the absence of a pedicle throughout ontogeny. The craniids are the sole Recent descendants. The mainly articulated Rhynchonelliformea is the largest subphylum as it embraces five Classes (Chileata, Obolellata, Kutorginata, Strophomenata and Rhynchonellata). Its synapomorphies include an organocarbonate shell with a fibrous secondary layer, the presence of a pedicle without a coelomic core and the development of a recognizable diductor muscle system controlling the opening of the valves about a hinge axis defined by interareas. All Recent brachiopod species articulating with cyrtomatodont teeth and sockets are rhynchonelliforms.

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The first Carboniferous and ?Permian marine macrofaunas from the Antarctic continent are described from three sites near Mount King, Alexander Island, Antarctic Peninsula. They include bivalves, brachiopods, bryozoans, crinoids, gastropods, a possible monoplacophoran, nautiloids and a possible serpulid or microconchid. Overall the faunas of two localities are Carboniferous in age and compare well with the Levipustula levis Zone of Argentina and eastern Australia, and are of Namurian (Serpukhovian–Bashkirian) age, based mainly on the brachiopod and bryozoan faunas. Less positive brachiopod evidence from a third locality indicates the presence of a linoproductid fauna of possible Carboniferous or Permian (Gzhelian–Artinskian) age, having affinities with the Argentinian Cancrinella fauna. The lithological and structural characteristics of the Mount King beds are comparable to the accretionary complex of the LeMay Group (hitherto of only proven Jurassic–Cretaceous age) of Alexander Island, in which they are provisionally placed. However, the beds may also correlate with the Trinity Peninsula Group (Carboniferous–Triassic) of the northern Antarctic Peninsula. The features of the Mount King beds are consistent with the presence of an accretionery complex related to an island arc in the Late Palaeozoic, but are not necessarily conclusive proof of the presence of such a terrane at that time in what is now Alexander Island.

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In the Lower Devonian the first productellids evolved from their chonetidine ancestors as the Productellinae. This subfamily was the stem group from which all the later Productidina evolved, yet three of its five subfamilies persisted to the end of the Permian. The main characters used in the new classification, here presented, for the Productellidae are described and reviewed, and the main changes seen during its evolution are discussed. Within this new classification five new genera are described: in the Overtoniinae are Barunkhuraya Lazarev from the latest Famennian, Onavia Lazarev from the Tournaisian, both from Mongolia, and Echinariella Lazarev (type species Krotovia jisuensiformis Sarycheva) from the late Permian of Transcaucasia; in the Marginiferinae there is Breileenia Brunton from the Visean of western Europe and in the Plicatiferinae is Maemia Lazarev from the mid and Upper Carboniferous on the coast of the Barents Sea. New species described in these genera are Barunkhuraya indrengynensis Lazarev, Onavia barunkhurensis Lazarev, Breileenia radiata Brunton, Maemia chaykensis Lazarev, and M. nana Lazarev.

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