Lasius nigroemarginatus Forel, 1874 is a F1 Hybrid between L. emarginatus (Olivier, 1792) and L. platythorax Seifert, 1991 (Hymenoptera, Formicidae)

Abstract

Lasius nigroemarginatus Forel, 1874, that has been synonymized in recent catalogues with Lasius emarginatus (Olivier, 1792), is shown to represent a F1 hybrid between L. emarginatus and L. platythorax Seifert, 1991. This conclusion was firstly drawn from numeric description of 16 phenotypic characters and the placement of four type workers of L. nigroemarginatus within vectorial space of the three possible parental species. These were represented by 144 workers of Lasius niger (Linnaeus, 1758), 90 workers of L. emarginatus and 94 workers of L. platythorax – with a coverage for all species by their whole Palaearctic range. The type sample was placed intermediate between (and clearly separated from) the clusters of L. emarginatus and L. platythorax in both Nonmetric Multidimensional Scaling and when run as a wild-card in a three-class linear discriminant analysis. Comparing structural and pigmentation characters one by one, the types of L. nigroemarginatus were intermediate between L. emarginatus and L. platythorax in five characters, closer to L. emarginatus in four characters and closer to L. platythorax in seven characters. The conclusions derived from the position in the morphological space were supported by data on swarming time and nest habitat selection and the odor perceived by the collector Forel. Lasius niger could be clearly excluded to represent a parental species. It is argued that the International Code of Zoological Nomenclature (ICZN) shows logical inconsistencies and explanatory weakness regarding the treatment of truly hybridogenous species and that the Articles 1.3.3, 17.2 and 23.8 of ICZN should be amended or re-written.