Lightiella magdalenina is the more recently cephalocarid species described
(La Maddalena Archipelago, Sardinia). This first important finding in the
Mediterranean sea fills a gap in the distribution of the genus and of the entire
class. The aim of the present study is to report some information about
distribution and biology of this cephalocarid species. L. magdalenina, like most
cephalocarid species, shows a pronounced anamorphic mode of development with
a gradual and sequential addition of segment and limbs throughout more of 17
stages of development. It is currently known from a single locality where 55
specimens have been found during more than nine years of sampling. The Type
locality is characterised by muddy sand bottom, very rich in organic matter with
leaf fragments of Posidonia oceanica; grain size analysis, has underlined that sand
is a very fine sand with an organic component of 95%. Zoobenthos was composed
of 11 different taxa; Cletopsyllidae and Normanellidae Copepoda are unknown for
Italy. A new species of family Cletopsyllidae, Isocletopsyllus sp. nov. has been
identified. Up to present, only one species Hutchinsoniella macracantha, have
been studied at molecular level. We report the partial sequences of two
mitochondrial genes of relevant importance for phylogenetic analysis (cytochrome
c oxidase I and cytochrome b) from Lightiella magdalenina. A reduced median
network analysis clarified the genetic relationships between the two cephalocarid
species
