Taxonomic composition of the helminth parasites of ictalurids and heptapterids (Osteichthyes: Siluriformes) in Mexico, with a hypothesis of biogeographical primary homology

Abstract

ICTALURIDAE AND HEPTAPTERIDAE (SILURIFORMES) ARE 2 FAMILIES OF FRESHWATER FISHES DISTRIBUTED IN MEXICO, WITH A NEARCTIC AND NEOTROPICAL ORIGIN, RESPECTIVELY. THIS GENERATES A PARTICULAR INTEREST IN THE STUDY OF ITS PARASITIC HELMINTHES FROM THE BIOGEOGRAPHICAL POINT OF VIEW. IN THIS STUDY WE PRESENT A CHECKLIST OF THE HELMINTH PARASITES OF THESE FRESHWATER FISHES, OBTAINED FROM BIBLIOGRAPHICAL SOURCES AS WELL AS FIELD WORK CONDUCTED DURING THE LAST FEW YEARS, AND WE USE THIS INFORMATION TO DESCRIBE HOST-PARASITE PATTERNS, TO UNCOVER THE BIOGEOGRAPHICAL HISTORY OF THESE ASSOCIATES. ALTOGETHER, BOTH FISH FAMILIES ARE INFECTED WITH 89 SPECIES OF HELMINTHS, 49 AS ADULTS AND 40 AS LARVAE, AND ONLY 2 OCCUR AS BOTH ADULTS AND LARVAE. TRACK ANALYSIS (PANBIOGEOGRAPHY) IS USED TO PROPOSE A BIOGEOGRAPHICAL HYPOTHESIS BY CONSIDERING THE DISTRIBUTION OF 16 OF THE 89 HELMINTH SPECIES RECORDED IN THESE HOSTS. THE HYPOTHESIS INDICATES THAT THE ASSOCIATES HAVE A COMMON BIOGEOGRAPHICAL HISTORY AND IN THE CASE OF SOME SPECIES OF ICTALURUS, THE TAXONOMIC COMPOSITION OF THEIR HELMINTH FAUNA IS PARTLY A RESULT OF THE SPECIATION EVENTS OF THEIR HOSTS. WE CORROBORATE THE GENERAL PATTERN OF THE HELMINTH PARASITES OF MEXICAN FRESHWATER FISHES, WHICH IS THE CIRCUMSCRIPTION OF HELMINTH SPECIES TO A PARTICULAR HOST FAMILY, WITH LIMITED HOSTSHARING EVEN WHEN HOSTS OCCURR IN SYMPATRY.