Systematic survey of Lithothamnion, Melobesia and Mesophyllum species (Hapalidiaceae, Corallinales, Rhodophyta) recorded along the Atlantic coast of Mexico

Family Hapalidiaceae is represented in the Atlantic coast of Mexico by three genera and five species. Lithothamnion sejunctum is a new record for Mexico and represents the third record since it was first described and L. crispatum is recorded for the first time for North America Continent. L. crispatum and L. occidentale are developing as maerl in the subtidal zone to 50 m depth. Melobesia membranacea has the widest distribution interval in the study area. Mesophyllum mesomorphum is a species which it has few records in the study area. Detailed accounts are provided for each species along with information on synonymy, collections examined, distribution, and habitat. Qualitative characters associated with tetrasporangial / bisporangial conceptacle roof morphology and anatomy have provided a reliable basis for delimiting the Atlantic Mexican species of Hapalidiaceae.