Conflict among data sources can be frequent in evolutionary biology, especially 
in cases where one character set poses limitations to resolution. Earthworm 
taxonomy, for example, remains a challenge because of the limited number of 
morphological characters taxonomically valuable. An explanation to this may be 
morphological convergence due to adaptation to a homogeneous habitat, resulting 
in high degrees of homoplasy. This sometimes impedes clear morphological 
diagnosis of species. Combination of morphology with molecular techniques has 
recently aided taxonomy in many groups difficult to delimit morphologically. 
Here we apply an integrative approach by combining morphological and molecular 
data, including also some ecological features, to describe a new earthworm 
species in the family Hormogastridae, Hormogaster abbatissaesp. n., collected in 
Sant Joan de les Abadesses (Girona, Spain). Its anatomical and morphological 
characters are discussed in relation to the most similar Hormogastridae species, 
which are not the closest species in a phylogenetic analysis of molecular data. 
Species delimitation using the GMYC method and genetic divergences with the 
closest species are also considered. The information supplied by the 
morphological and molecular sources is contradictory, and thus we discuss issues 
with species delimitation in other similar situations. Decisions should be based 
on a profound knowledge of the morphology of the studied group but results from 
molecular analyses should also be considered.