Subfamily Microrbiniinae Blake, 2000

Type genus. Microrbinia Hartman, 1965 . Designated by Blake, 2000.

Diagnosis. (after Blake 2017). Body small, lacking distinct regions; parapodia lateral throughout, none shifted dorsally. Prostomium broad, bluntly rounded or more elongate and conical; nuchal organs present. Peristomium with 1–3 achaetous rings, separated from prostomium. Noto- and neuropodial postsetal lamellae reduced to short lobes. Bases of podia separated throughout; setal tori simple. Setae consisting of capillaries, blunt-tipped spines or uncini and swan hooks present or absent; furcate setae typically absent. Branchiae typically absent, if present; simple throughout, oval to flattened with two longitudinal rows of cilia. Pygidium with few cirri or cirri absent.

Inclusive genera. Microrbinia, Orbiniella, Proscoloplos, and Pettibonella .

Remarks. Only species belonging to the genus Orbiniella were present in this study. Six new species were identified.