No abstract

A taxonomic revision of species related to Mordellistenahirtipes Schilsky, 1895 is presented. Five species among the M.hirtipes complex are recognised: M.hirtipes Schilsky, 1895, M.pseudohirtipes Ermisch, 1965, M.purpurascens Costa, 1854, M.balearica Compte, 1985, and M.irritans Franciscolo, 1991. Descriptions, differential diagnoses, an identification key, and new distributional records are provided. Principal Component Analysis is performed for visualisation of differentiation between taxa. The following taxonomic acts are proposed: Mordellistenapodlussanyi Czető, 1990 and M.aegea Franciscolo, 1949 are proposed as junior subjective synonyms of M.hirtipes Schilsky, 1895; M.fageli Ermisch, 1969 and M.pseudohirtipeskrotosensis Czető, 1990 are proposed as junior subjective synonyms of M.pseudohirtipespseudohirtipes Ermisch, 1965; M.geronensis Ermisch, 1977 and M.istrica Ermisch, 1977 are proposed as junior subjective synonyms of M.purpurascens Costa, 1854.

Ancyronyx clisterisp. nov. (Coleoptera, Elmidae) a new spider riffle beetle discovered from northern Borneo (Brunei; Sabah and Sarawak, Malaysia) and the larva of Ancyronyx sarawacensis Jäch are described. Illustrations of the habitus and diagnostic characters of the new species and the similar and highly variable A. sarawacensis are presented. Differences to closely related species, based on DNA barcodes and morphological characters, are discussed. Association of the larva and the imago of A. sarawacensis, and the occurrence of Ancyronyx procerus Jäch in Peninsular Malaysia and Sabah are confirmed by using COI mtDNA sequences.

Two new species of Ancyronyx Erichson, 1847 (Coleoptera: Elmidae) are described from Borneo: A. pulcherrimus (Brunei) and A. reticulatus (Sabah). Habitus views, illustrations of important characters as well as plastron structures of Ancyronyx reticulatus are presented and discussed.

The current interpretation of two common European species, Mordellistena minima Costa, 1854 and M. pseudorhenana Ermisch, 1977, is based on misidentification. The confusion regarding the identity of the species is fixed based on the revised type material. Here, the species are redescribed, and diagnostic characters are provided. Mordellistena pseudorhenana is revalidated. Mordellistena emeryi Schilsky, 1895 is recognised as a new synonym of M. minima. Mordellistena sajoi Ermisch, 1977 is recognised as a new synonym of M. pseudorhenana. Lectotype and paralectotypes of M. emeryi are designated. Mordellistena pseudorhenana is reported for the first time from Bosnia and Herzegovina, Slovenia, and Switzerland. Two morphotypes of M. pseudorhenana differing in size and shape of the parameres are recognised. Morphological differences are quantified and displayed using principal component analysis. In addition, DNA barcodes have been used for the first time in family Mordellidae to examine the divergences between the species and to interpret the morphological variability observed in M. pseudorhenana. Low genetic divergences did not provide the evidence for considering the morphotypes as separate species. The discrepancy between the morphological and molecular evidence raises questions about the efficiency of the CO1 gene for Mordellidae identification and the stability of morphological traits conventionally used for species separation.