Biology and functional morphology of Kendrickiana gen. nov. veitchi (Bivalvia: Anomalodesmata: Clavagelloidea) from southern Australia

. The largest extant species of the adventitious tube‐building Clavagelloidea has hitherto been placed in the genus Foegia (itself formerly a subgenus of Brechites ), the type species of which is the Western Australian F. novaezelandiae (B ruguiére 1792). Following examinations of and comparison with F. novaezelandiae and the southern Australian F. veitchi , the latter is herein placed in its own new genus Kendrickiana . Individuals of both F. novaezelandiae and K. veitchi are essentially amyarian in terms of adductor and pedal retractor muscles, but in the latter species the connection to the adventitious tube is located dorsally by an unique horseshoe‐shaped array of muscular papillae, which are inserted into holes in the tube. K. veitchi is different from other clavagelloids too in that the siphons are capable of only limited retraction into the tube. Their extension in K. veitchi is almost exclusively by hydraulic means because the complex internal siphonal muscles seen in other species of the Clavagelloidea, and which act antagonistically with extensive blood‐filled haemocoels, are vestigial. Kendrickiana can also be separated from Foegia in other anatomical respects. For example, members of the former have paired anterior suspensory muscles, and vestigial posterior pedal retractor muscles with pericardial proprioreceptors associated with them (as in Humphreyia and Dianadema ), whereas the latter does not. Similarly, in Foegia there is a muscularized pedal disc, not found in Kendrickiana . Members of F. novaezelandiae are inhabitants of intertidal hypoxic muds, whereas those of K. veitchi apparently live exclusively in subtidal sea grass beds.