ON THE PRESENCE OF ANATRIAENES IN PACHASTRELLIDAE (PORIFERA, DEMOSPONGIAE) - EVIDENCE FOR A NEW PHYLOGENETIC FAMILY CONCEPT

Species bearing long-shafted triaenes do not fit the traditional diagn osis of the family Pachastrellidae. However, the present study confirm ed the occurrence of anatriaenes in Characella tripodaria (= Sphinctre lla linaresi and Poecillastra rudiastra, n. syn.) and Poecillastra arm ata. Although anatriaenes were also formerly described in some specime ns of Characella pachastrelloides, the results of our re-examination s uggest that these spicules are not proper of this species, but foreign material incorporated from the sediment. Because of the presence of a natriaenes in C. tripodaria and P. rudiastra, the generic diagnoses of Poecillastra and Characella have been amended. Apart from the taxonom ic interest, the present finding requires us to reconsider the possibi lity that the presence of anatriaenes is ancestral in the Pachastrelli dae. Under such an assumption, Pachastrellidae can no longer be consid ered as a primitive astrophorid family and its calthrops-pseudocalthro ps should be regarded as a type of reduced triaenes.