The problem of species delimitation within the endemic Lake Baikal sponges Lubomirskiidae

Abstract

The delimitation of species within the endemic sponge family Lubomirskiidae is difficult. Along with specimens falling within the range of morphological variability of previously described specimens, we found specimens with intermediate morphological characteristics. The largest number of such specimens had intermediate characteristics between representatives of the genera Lubomirskia and Baikalospongia. For some species of these genera, a common feature is the structure of megasclera in the form of oxeas of a similar size. At the same time, the genera Swartschewskia and Rezinkovia have less variable morphological characteristics, so the identification of species belonging to these genera based on morphology is not difficult. The results of our study indicate the need for delimitation of Lubomirskiidae species based on molecular data.