Base by Base and Scale by Scale: Defining the Biodiversity of Interstitial Solenogastres via Integrative Taxonomy
The fauna of the marine mesopsammon is still poorly known. Recent molecular approaches to species delineation have revealed a high degree of cryptic speciation raising doubts as to whether traditional taxonomy reliably reflects biodiversity patterns. Solenogastres (Neomeniomorpha) are prominent members of the molluscan meiofauna and can be found world-wide in sediment samples from the intertidal to the deep sea. Only few of these minute, interstitial ‘worm-mollusks’ have been formally described. We performed a multi-barcoding and molecular species delineation approach based on mitochondrial and nuclear markers analyzing interstitial Meiomeniidae from Bermuda, Florida (USA), Belize, Panama and several collecting sites in Brazil. Furthermore, we redescribed the valid Meioherpia and Meiomenia species in our material using scanning electron microscopy and 3D-microanatomical reconstructions from histological semi-thin sections, mining for additional characters for species delineation in meiofaunal Solenogastres.