A new semiaquatic worm (Annelida, Oligochaeta) from southeastern Mexican tropical rain forests.

A new Oligochaete worm genus with a single species is described from tropical rain forests of Southern Mexico. Lacandodrilus paludosus Fragoso & Rojas gen. et sp. nov., found in sandy and acid poor swampy soils, presented a characteristic morphology of semiaquatic oligochaetes. The new taxon is holandric, with male pores and ovaries in segment 13, with genital prostatic- like lobular glands in segments 13 and 14 and with long seminal vesicles contained within ovisacs. It is also characterized by exonephric holonephridia covered by a peritoneal granular layer, septal glands and long vascular commissures in former segments. It presents a pair of spermathecae without diverticula in segment 10 and it lacks gizzards, typhlosole or esophagus glands. The new taxon is tentatively placed in family Alluroididae, waiting for additional histological studies that will clarify some characters.