Since we reported on Caenorhabditis biodiversity in 2011, 13 new species have been discovered. The number of species in culture is now 36, and 50 species are known. Most new species were isolated from rotting plant material, but two were found in fresh figs (N. Kanzaki pers. comm.) and one in the hind gut of a millipede (W. Sudhaus pers. comm.). Three of the new species were isolated from temperate regions, the others from tropical regions. Preliminary phylogenetic analyses with molecular data for 36 species confirm the existence of two well-supported large sister clades, the Elegans super-group with now 21 species and the Drosophilae super-group with 11 species. C. plicata, C. sp. 1 and C. sonorae as well as a C. sp. 21 branch off basally. Still, no sister species of C. elegans has been found. Hybridization is now observed in crosses of 5 species pairs (C. angaria - C. sp. 12, C. briggsae - C. sp. 9, C. remanei - C. sp. 23, C. sp. 5 - C. sp. 26, C. sp. 8 - C. sp. 24), providing opportunity for studying the evolution of hybrid incompatibility in Caenorhabditis. In at least one case, crosses between individuals from some but not all populations show reproductive isolation, suggesting incomplete speciation. Using light and scanning electron microscopy, we are evaluating morphological characters of all cultured species in detail. Across Caenorhabditis, the morphological diversity is large, especially in features of the male tail and the stoma. However, no or only subtle differences are found between many species of the Elegans super-group. Mapping phenotypic characters onto the phylogeny shows extensive homoplasy (convergent evolution or secondary loss) across all character complexes. Morphological, biogeographical, ecological, sequence, and taxonomic data on all Caenorhabditis species is now available through an open-access online database RhabditinaDB
(http://wormtails.bio.nyu.edu/Databases). Strains of most species are available through the CGC.