of families differs between authors. The species count is in constant flux due to taxonomic work as well as description of new species. On the other hand, our understanding of catfish should increase in the next few years due to work by the ACSI. Between 2003 and 2005, over 100 species have been named, a rate three times faster than that of the past century. In June 2005, researchers named the newest family of catfish, Lacantuniidae, only the third new family of fish distinguished in the last 70 years (others being the coelacanth in 1938 and the megamouth shark in 1983). The new species in Lacantuniidae, Lacantunia enigmatica, was found in the Lacantun river in the Mexican state of Chiapas. The higher-level phylogeny of Siluriformes has gone through several recent changes, mainly due to molecular phylogenetic studies. While most studies, both morphological and molecular, agree that catfishes are arranged into three main lineages, the relationship among these lineages has been a contentious point in which morphological and molecular phylogenetic studies, performed for example by Rui Diogo, differ. The three main lineages in Siluriformes are the family Diplomystidae, the denticulate catfish suborder Loricarioidei (which includes the families Nematogenyidae, Trichomycteridae, Callichthyidae, Scoloplacidae, Astroblepidae, and Loricariidae, which is sometimes referred to as the superfamily Loricarioidea), and the suborder Siluroidei, which contains the remaining families of the order. According to morphological data, Diplomystidae is usually considered to be the earliest branching catfish lineage and the sister group to the other two lineages, Loricarioidei and Siluroidei. Molecular evidence usually contrasts with this hypothesis, and shows the suborder Loricarioidei as the earliest branching catfish lineage, and sister to a clade that includes the Diplomystidae and Siluroidei. While in the first study this relationship was proposed the "morphological" hypothesis could not be rejected, the new, "molecular" phylogenetic hypothesis was later obtained in numerous other phylogenetic studies based on genetic data. However, a recent study based on molecular data argued that the previous "molecular" hypothesis is the result of phylogenetic artifacts due to a strong heterogeneity in evolutionary rates among siluriform lineages. In that study it was suggested that the fast evolution of the Loricarioidei suborder was attracting this clade to the outgroups through long branch attraction, incorrectly placing it as the earliest-branching catfish lineage. When a data filtering method was used to reduce lineage rate heterogeneity (the potential source of bias) on their dataset, a final phylogeny