New insights in the biogeographical distributions of two Spionidae (Annelida) from the NE Atlantic and Mediterranean French coasts

We report the first occurrences of Spiophanes afer Meisner, 2005 and Prionospio cristaventralis Delgado-Blas, Diaz-Diaz & Vieitez, 2018 from French marine waters (from the southern part of the Bay of Biscay in NE Atlantic, and the Gulf of Lion in the Mediterranean Sea). Morphological characters of S. afer include the presence of an occipital antenna, dorsal ciliated organs extending to chaetigers 13–15, neuropodial hooks from chaetiger 15, ventrolateral intersegmental pouches from chaetigers 14–15, chaetal spreaders of “2+3 type”, and conspicuous dark brown pigmentation on parapodia of chaetigers 9–13. Prionospio cristaventralis has four pairs of branchiae (1st and 4th pinnate, 2nd and 3rd apinnate), ventral crests from chaetigers 11–12, high dorsal crests on chaetigers 10–11, and very large notopodial prechaetal lamellae on anterior chaetigers. Both records represent northern extensions of their known distributions. However, the presence of S. afer on French coasts may have been overlooked for several decades. The validity of the recently proposed Spiophanes adriaticus is questioned.