Phylogeny of the genus Aporcelinus Andrassy, 2009 (Nematoda: Dorylaimida: Aporcelaimidae) with description of two new species from Costa Rica

Four Costa Rican species of the genus Aporcelinus, two new (A.itecrii sp. nov. and A.mesoamericanus sp. nov.) and two previously known (A.amazonicus and A.insularis) are studied. Morphological descriptions are provided, including line drawings of the new species, light microscopic images of the four species, and scanning electron micrographs of A.mesoamericanus sp. nov. Nine D2-D3 28S rRNA gene sequences of variable length are obtained for four species, and analyzed with Bayesian inference. The new species are compared to their relatives, and new relevant information about the known species is given. Morphological data and 28S sequences are used to analyze the evolutionary relationships of the genus and to elucidate its phylogeny with an integrative approach. Thus, the monophyly of Aporcelinus is confirmed on the basis of a definite and recognizable morphological pattern and a highly supported clade obtained by means of molecular genetic analysis. Its internal evolutionary relationships are not definitely resolved, but according to this analysis the new species share a recent ancestor, and are closer to other South American species than to the representative from the Asian Far East. Doubts are raised about the classification of Aporcelinus under Aporcelaimidae, as originally proposed, as molecular genetic analysis shows a tentative closer (but not highly supported) relationship with Allodorylaimus, a member of the family Qudsianematidae.