Contributions to Zoology, 71 (4) (2002)Ana Isabel Camacho; Isabel Rey; Beatriz A. Dorda; Annie Machordom; Antonio G. Valdecasas: A note on the systematic position of the Bathynellacea (Crustacea, Malacostraca) using molecular evidence

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Introduction

The relative merit of the systematic position given to a certain group of animals or plants, depends more often than not on how thoroughly the group has been studied rather than the technique used. Contrasting morphological studies with molecular ones has often had the undesirable effect of concealing that neither view, morphological or molecular, is usually homogeneous amongst the specialists. The traditional way of working is to use the latest information or the latest hypothesis published in order to select those views that are going to be compared. However, it must be universal that where there is more than one taxonomist working on a group there will not be a single hypothesis or interpretation of the group’s descent. How big or small are these irrelevant discrepancies and does it not invalidate this universal law.

The group known as “Bathynellacea” (Serban, 1972) is a good example of the above. First discovered by Vejdovsky (1882), their systematic (position) has been a problem since then. They were considered an “aberrant” member of Malacostraca (Calman, 1909). Although nobody knows what “aberrant” members in evolution are, the term generally implies organisms that do not fit well into our limited reconstructed ground patterns. Other authors have designated them as simplified syncarids (see Schminke, 1981). However, the morphological taxonomist that most deeply studied the internal and external morphology of the Bathynellacea, Eugene Serban, never joined the Bathynellacea with the Syncarida, but proposed a more radical model of relationships (Serban, 1970, 1972): the order Bathynellacea in his scheme would belong to the superorder Podophallocarida Serban, 1970 under the infraclass Eonomostraca Serban, 1972. True Syncarida, on the other hand, would be placed by Serban under a different infraclass, the Anomostraca.

In this paper we present the first nucleotide data for a bathynellacean species and apply these towards an analysis of the relationship of this group with other malacostracan crustaceans.