Body oval with rather pointed anterior end or elongate with sides nearly parallel and rounded ends; shoulders or lateral projections absent. Tegument with or without spines. Papillae on ventral surface form three rows of discrete papillae. Oral sucker small, terminal or subterminal. Caeca simple, terminate medially or posteriorly to testes without uniting. Testes some developed or not. Cirrus-sac median, claviform, slender anteriorly. Cirrus smooth or may bear small tubercles. Genital pore typically immediately postbifurcal but anterior to bifurcation in some species. Ovary rounded, intercaecal, intertesticular. Mehlis' gland median, pre-ovarian. Laurer's canal reported in some species. Uterine coils occupy third quarter of body. Excretory vesicle small; pore dorso-subterminal. In intestine and/or caeca of birds (manily Anseriformes, Ardeiformes, Charadriiformes, Galliformes, Gruiformes, Phoenicopteriformes) and mammals (Mormoopidae, Muridae, and perhaps other chiropterans); cosmopolitan.
Sources: Bray, R.A., Gibson, D.I., and Jones, A. 2005. Keys to the Trematoda, Vol. 2, p. 393.
