Description: "Body medium to very large, markedly elongate and slender. Forebody extremely short; anterior half of hindbody attenuated; maximum width posteriorly. Tegument armed with papilliform spines in close transverse rows anteriorly; lateral body-margins distinctly serrate, appearing pseudosegmented. Collar small, reniform, with 31-64 spines. Marginal spines very small; angle spines 2x6-9, blunt, large; ventral ridge present. Oral sucker and pharynx small, of similar size. Ventral sucker fairly close to anterior extremity. Oesophagus short. Intestinal bifurcation just anterior to ventral sucker. Testes round, elongate-oval or subrectangular, smooth or irregular, contiguous or separated, fairly close to posterior extremity. Cirrus-sac long, slender, reaches into hindbody to about 2-4 lengths of ventral sucker. Pars prostatica tubular, long. Cirrus muscular, smooth. Ovary rounded, median, close to posterior extremity. Mehlis' gland diffuse, larger than ovary. Uterus very long, tightly spirally coiled, occupies entire intercaecal field between ovary and about mid-body, extends anteriorly as straight tube containing no eggs. Metraterm shorter than cirrus-sac. Eggs numerous, rather elongate, with long polar filament. Vitelline fields non-confluent, pretesticular, between ovary and mid-body level; follicles large. Excretory vesicle large; pore terminal. In intestine of birds (Pelecaniformes and Charadriiformes); Europe, Asia, Africa, North America, Oceania. Type species A. croaticus (Stossich, 1889) Stossich 1905" (Bray et al., 2005).
Life Cycle: Adults: "In intestine of birds (Pelicaniformes and Charadriiformes)" (Bray et al., 2005).
Sources: Bray, R.A., Jones, A., and Gibson, D.I. 2005. Keys to the Trematoda, Vol. 2, p. 53.