Studies on Monogenetic Trematodes. XXVI. Dactylogyrinae from California with the Proposal of a New Genus, Pellucidhaptor

Abstract

The following species are described as new: Dactylogyrus egregius from Richardsonius egregiwus (Girard), D. microlepidotus from Orthodon microlepidotus (Ayres) and Lavinia e. exilicauda Baird and Girard, D. orthodon from Orthodon microlepidotus (Ayres), and Pellucidhaptor pellucidhaptor from Richardsonius egregius (Girard). The following described species are recorded: Dactylogyrus anchoratus (Dujardin, 1845), D. vastator Nybelin, 1924, D. wegeneri Kulwiec, 1927 (all) from Carassius auratus (Linnaeus); and D. richardsonius Monaco and Mizelle, 1955 from Richardsonius egregius (Girard). Sixteen hooks (8 pairs) were observed in all of these species. The genus Pellucidhaptor differs from Dactylogyrus by the presence of eight pairs of haptoral hooks of the same approximate size, doubly recurved anchor points, nonconfluent intestinal crura, and anchor wings that arise on the anchor bases instead of on the anchor shafts. Taxonomic investigations on the genus Dactylogyrus began in 1932 with the description of D. extensus by Mueller and Van Cleave. Presently there are 50 valid North American species in this genus which together with the three described herein make a total of 53. Hosts utilized in the present work were seined or trapped and frozen prior to preservation in 3% formalin. Branchial material was shaken in a 100-ml graduate cylinder, approximately two-thirds full of tap water, to free the parasites from the gill filaments. The mixture then was diluted and decanted until sufficiently clear for reliable examination with a dissecting microscope. Parasite specimens were selected with a capillary pipette and mounted one to a slide in a glycerin-gelatin medium. This medium is prepared by dissolving with heat, 10 g gelatin in 30 ml tap water after which sufficient glycerin is added to make a 3% mixture. A few crystals of thymol are added as a preservative. Observations were made with a phase contrast microscope, measurements and illustrations with the aid of a filar micrometer ocular and a camera lucida, respectively. Measurements are in microns. Dactylogyrus anchoratus (Dujardin, 1845)