Checklist and phylogeny of Exxidae (Oligochaeta)

The genus Exxus Gates, 1959 was overlooked until its designation as type-genus of the Caribbean earthworm family Exxidae Blakemore, 2000. Four new inclusions are: Exxus barroi, Exxus cubitasensis, Exxus righii (all comb. nov. from Cubadrilus Rodriguez and Fragoso, 2002), plus Exxus taina (Rodriguez and Fragoso, 1995) comb. nov., that comply with type Exxus wyensis Gates, 1959, and with Neotrigaster complutensis (Borges and Moreno, 1991) and N. rufa (Gates, 1962), the type-species of junior synonym Neotrigaster James, 1991. Other tentative species inquirendae are Trigaster minima Friend, 1911 and Trigaster setarmata (?auct.). Phylogenetic placement and distribution of Exxidae relative to Benhami-inae/idae, Diplocardi-inae/idae, Trigastrinae and of these in relation to Acanthodrilidae, Octochaetidae and Megascolecidae are discussed based on key morphological characteristics of the respective type-species of each.