Ferreiraella Sirenko, 1988

Sigwart, Julia D. & Sirenko, Boris I., 2012, Deep-sea chitons from sunken wood in the West Pacific (Mollusca: Polyplacophora: Lepidopleurida): taxonomy, distribution, and seven new species, Zootaxa 3195, pp. 1-38 : 26

Ferreiraella Sirenko, 1988

Type species. Ferreiraella carribbensis Sirenko, 1988 by original designation.

Diagnosis. Valves without raised sculpture, but with aesthete caps clearly visible; usually with well developed, unslit insertion plates on terminal valves. Girdle lacking spicular armature on ventral side. Girdle wide, densely covered in spicules on dorsal side. Radula with distinctive marginal spatulate accessory plate.

Remarks. Ferreiraella is the sole genus in the family Ferreiraellidae . Six ferreiraellid taxa are known from the western Pacific ( Table 2), of which four are known only from the type locality.

Sirenko (2001) reported two taxa of ferreiraellid chitons from Vanuatu and New Caledonia: Ferreiraella plana ( Nierstrasz, 1905) and a new subspecies of a taxon previously known only from New Zealand, Ferreiraella xylophaga karenae Sirenko, 2001 . Both of these forms were encountered in the present material from Vanuatu [Boa 1] and the Solomon Island [Solomon 2].

The western Pacific species of ferreiraellids are all very similar, and only slight conchological features distinguish them. Sirenko (2001) questioned the validity of these species. However, there are clearly two distinguishable morphotypes within this material, the largest populations sampled to date, which can be identified as F. p l a n a and F. x. karenae .

Ferreiraellid taxa in the western Pacific are differentiated by the arrangement of their aesthetes, the number of micraesthetes on each megalasthete, the valve shape, which varies from cardioid to oval, and the relative size of the insertion plate on the head valve. Without better samples of more species, the relationships and taxonomic validity of other ferreiraellids cannot be determined.