This study describes bioerosion traces ascribed to either predation or endo- and epibiont activity in twenty assemblages from the Mediterranean region and Paratethys, spanning in age from Eocene to Recent. Statistical analysis of the distribution of bioerosion traces among genera and assemblages revealed that there is higher drilling predation intensity on smaller species. Larger species seem to be primarily affected by non-drilling predators. Greatest variety in types of bioerosion could be related to species’ ecology and body size. Both major categories of bioerosion (etchings and traces of predatory activity) vary considerably among samples. Different genera show significant differences in the frequency of different bioerosion types. Shell size seems a major factor contributing to these differences.

Spire-bearing brachiopods formally comprise four different rhynchonelliform orders. A calcified spiral brachidium (presumably supporting a spirolophe when alive) and variable median fold and sulcus (probably aiding separation of incurrent from excurrent flows) are peculiar characteristics they all share. Inferences regarding feeding current systems for these extinct taxa have long remained controversial. Two rival models (the Williams–Ager model and the Rudwick–Vogel model) have been developed, each of which has gained supporters as well as critics over the years. In this present paper they are both contrasted and reassessed on the basis of available evidence, together with a new approach that combines: (a) a morpho-functional analysis applying the plankton net as a suitable seston-collecting paradigm; (b) a review of actualistic data showing that all extant spirolophes are functionally inhalant (irrespective of water entering the valves laterally or not); (c) an evaluation of known outcomes from flume experiments yielding consistent empirical results where gaping shells are oriented transversally and dorsally upcurrent; and (d) a reappraisal of the distributions of certain epizoobionts and endosymbionts revealing compatible patterns. The evidence thus accumulated supports the main conclusion that, in most groups (with laterally tapering spiralia), the inhalant current was located medially with the exhalant currents on either side; only in atrypides (with centrally to dorsally tapering spiralia) does the reverse situation appear to have occurred.

Animals can respond in three main ways to environments that change and deteriorate. They can cope with their inherent physiological flexibility, evolve or adapt to new conditions, or migrate away to areas consistent with survival. The main factors dictating survival are the rates of change and capacities of species to cope. Articulated brachiopods are known as a group that employ low energy solutions and exhibit slow rates in life histories characters, especially in growth and metabolic rates. This way of life carries with it a range of consequences, including poor abilities to raise metabolic rates to perform work. This brings with it poor abilities to cope with elevated temperature. Slow growth, deferred maturity and low feeding rates make them less likely to produce novel adaptations compared with other marine invertebrate taxa. Being largely restricted to hard substrata and low energy supply environments also makes it harder for them to migrate to new sites compared to other groups, because of the large geographic distances between colonisable areas. The only clear area they may have that gives them advantages is in the flexibility of their larval release strategies, where settlement can be from very short, millimetre-scale distances to hundreds of kilometres.

This two-part special issue, Brachiopod Research into the Third Millennium, is published in honour of Sir Alwyn Williams (8 June 1921–4 April 2004). One section deals with fossil brachiopods while the other concentrates on aspects of modern material. The special issue comprises 23 invited papers, all dealing with current brachiopod research. In producing this special issue we honour the immense contribution made by the late Alwyn Williams to this field of research.