HELEOBIA IS THE MOST SPECIOUS GENUS IN THE FAMILY COCHLIOPIDAE, IN WHICH MANY SPECIES ARE MORPHOLOGICALLY SIMILAR. HERE WE USED MORPHOLOGICAL, MICROSTRUCTURAL AND PHYLOGENETIC CRITERIA TO INVESTIGATE SPECIES DELIMITATION WITHIN THE HELEOBIA CHIMBAENSIS COMPLEX ON THE ATACAMA DESERT COAST. THE RANGE INCLUDED SUBDIVIDED POPULATIONS OF THE SPECIES, THE SUBSPECIES HELEOBIA CHIMBAENSIS CONICA, AND THE ALLOPATRIC SNAILS FROM LOS PERALES, FIRST RECOGNIZED AS A POPULATION OF H. CHIMBAENSIS AND MORE RECENTLY CONSIDERED A CANDIDATE SPECIES OF THE GROUP. TRADITIONAL SHELL CHARACTERS, MORPHOMETRIC ANALYSIS, OPERCULUM, AND PROTOCONCH WERE EITHER UNINFORMATIVE OR AMBIGUOUS TO SEPARATE TAXA. HOWEVER, THE PHYLOGENETIC ANALYSIS IDENTIFIED H. CHIMBAENSIS, H. CHIMBAENSIS CONICA AND FOUR ADDITIONAL POPULATIONS OF THE SPECIES AS A MONOPHYLETIC GROUP WHILE THE POPULATION FROM LOS PERALES WAS RECOVERED AS A DISTANTLY EVOLUTIONARY SIGNIFICANT UNIT FOR WHICH THE NAME HELEOBIA PERALENSIS SP. NOV. IS PROVIDED HERE. WHILE THE GEOGRAPHIC ISOLATION AND LIMITED DISPERSAL SEEM TO HAVE INFLUENCED THE DIVERSIFICATION AND CURRENT DISTRIBUTION OF H. CHIMBAENSIS IN ATACAMA, THE ORIGIN OF HELEOBIA PERALENSIS SP. NOV. REMAINS UNCLEAR BECAUSE OF UNCERTAIN RELATIONSHIPS. A CONSERVATION STATUS ASSESSMENT ACCORDING TO IUCN CRITERIA AND NATURESERVE METHODOLOGY SUGGESTS THAT BOTH H. CHIMBAENSIS AND HELEOBIA PERALENSIS SP. NOV. FACE A HIGH RISK OF EXTINCTION.

THE NEW ZEALAND MUDSNAIL POTAMOPYRGUS ANTIPODARUM (GRAY, 1843) HAS BEEN CONSIDERED AS ONE OF THE MOST INVASIVE MOLLUSKS WORLDWIDE AND RECENTLY WAS LISTED AMONG THE 50 MOST DAMAGING SPECIES IN EUROPE. IN THE PRESENT PAPER, WE REPORT FOR THE FIRST TIME THE PRESENCE OF P. ANTIPODARUM IN THE MAULE RIVER BASIN, CHILE. THE IDENTITY OF THE SPECIES WAS BASED ON ANATOMICAL MICRODISSECTIONS, SCANNING ELECTRON MICROSCOPY COMPARISONS, AND DNA BARCODE ANALYSIS. THIS FINDING CONSTITUTES THE SOUTHERNMOST RECORD OF THE SPECIES UNTIL NOW IN THIS COUNTRY AND SOUTH AMERICA.

THE RANGE DISTRIBUTION OF HELEOBIA TRANSITORIA (BIESE, 1947) IS CONFINED ONLY TO ITS TYPE LOCALITY, QUEBRADA CACHINA, A RAVINE LOCATED ON THE ATACAMA DESERT COAST IN THE ANTOFAGASTA REGION, NORTHERN CHILE. THE SPECIES IS CLASSIFIED AS ?EN PELIGRO CRÍTICO? ACCORDING TO MINISTRY OF THE ENVIRONMENT OF CHILE, A CATEGORY EQUIVALENT TO CRITICALLY ENDANGERED (CR) OF THE IUCN RED LIST OF THREATENED SPECIES, IN PART FOR ITS RESTRICTED DISTRIBUTION. THIS PAPER REPORTS THE OCCURRENCE OF H. TRANSITORIA IN THE ATACAMA REGION, CHILE, AFTER THE STUDY OF MORPHOLOGICAL CHARACTERS USING LIGHT AND SCANNING ELECTRON MICROSCOPY. THIS NEW RECORD HIGHLIGHTS CONSIDERING THE LIMITED DISTRIBUTION AND CURRENT CONSERVATION STATUS OF THE SPECIES.