Branchiae simple or branched, from chaetiger 8 or later.
Anterior abdominal notopodial post-chaetal lobes triangular, similar in length to branchiae (Fig.
siciliensis, the earliest appearance of branchiae
is setiger 92 and can
The photo shows a Mediterranean meadow of Posidonia oceanica with schools of fish, (sparids and serranids) and by a tubicolous polychaete, the spiral tubeworm (Spirographis spallanzani), with its branchiae extended.
In the foreground in the lower part of the image, the tubes of a group of vestimentiferans are visible, some showing the highly vascularized branchiae, reddish in the photo.
Dendritically branched branchiae
occur in the posterior setigers.
Species identification was based on the morphological characters of rostrum, carapace, branchiae
, antennule, antenna, third maxilliped, pereiopods, pleopods, abdomen, telson, petasma, thelycum, and the colored pattern of the whole body.
There are morphological similarities between these two groups, such as the presence of a retractable head, a pair of grooved palps, an anterior ring of branchiae
, and a gelatinous mucus sheath, although some of these features are not exclusive to these taxa.
Fauchald (1992:284) commented that this species was described on the basis of an illustration and that de Quatrefages (1866:337) referred it to Marphysa; however, the latter author regarded the species as being deprived of branchiae
and probably belonging in Lumbrineridae.
Each abdominal segment has paired branchiae
and either a single (first few abdominal setigers) or double ciliary band, with two closely apposed bands of tufted cilia.
On the contrary, some features were regarded as useful such like the start of branchiae
and their development, as far as the specimen's age is taken into account, and the color of aciculae.
In many groups, there is a measure of heteronomy in segment form, such as groups of segments bearing branchiae
in spionids, or nereidids with differing anterior and posterior parapodial morphology.
is characterized by the number of its thoracic chaetigers, branchiae
, uncini and bilobed abdominal neuropodia with protruding aciculae.
Three body regions were clearly visible from external features: the head, which lacked branchiae
and was seemingly quite muscular; the mid-body, which had branchiae
and was much less rigid; and the tail, which lacked branchiae
and was sticky, translucent, and quite glandular in appearance.
Nevertheless, the presence of dendritic branchiae
from setiger three to the end of the body, and the absence of eyes suggests that they could be a different species.