Redescription and new host record of Capsala laevis (Monogenoidea: Capsalidae: Capsalinae) from gill of roundscale spearfish, Tetrapturus georgii (Perciformes: Istiophoridae) in the northwestern Atlantic Ocean.

Specimens of a capsalid collected from the gill arches of 2 roundscale spearfish, Tetrapturus georgii Lowe, 1840, (Perciformes: Istiophoridae), captured in the northwestern Atlantic Ocean were identified as Capsala laevis (Verrill, 1875) Johnston, 1929 by having the combination of papillae on the ventral surface of haptor, dorsomarginal body sclerites in a single column extending the entire body length, haptoral accessory sclerites, conical papillae distributing over the ventral body surface, and an anterior attachment organ with a fimbriated posterior margin. The new specimens plus the holotype were used to conduct a taxonomic redescription of C. laevis using light and scanning electron microscopy. We documented that the holotype (USNPC No. 7179) and the new specimens of C. laevis from roundscale spearfish each had papillae on the ventral surface of the anterior attachment organs and sensory papillae on the dorsal body surface. Although data are insufficient at this time to justify proposal of a new species, the new specimens differed from the holotype and published accounts of C. laevis by having a sinistral dorsomarginal patch comprising 27-35 sclerites whereas the holotype has a dorsomarginal patch comprising 60 sclerites. Capsala laevis morphologically most closely resembles Capsala ovalis (Goto, 1894) Price, 1938 , but can be most easily differentiated from it by having dorsomarginal body sclerites. This represents the first record of any parasite from the recently taxonomically resurrected roundscale spearfish, long considered by some as a junior subjective synonym of white marlin, Tetrapturus albidus Poey, 1860 and, concomitantly, a new host record for Capsalidae Baird, 1853. An updated list of host records for C. laevis is provided. A perusal of that literature reveals that the identity of the type host for C. laevis is indeterminate beyond Istiophoridae species and that subsequent reports of the type host as ' T. albidus ' are presumptuous (originally reported in 1875 by Verrill as "bill-fish" only). Our results indicated that 2 records of C. laevis from the swordfish, Xiphias gladius Linnaeus, 1758, (Perciformes: Xiphiidae) are dubious, i.e., study of the museum voucher USNPC No. 8154 indicates that Linton's 1940 record from the northwestern Atlantic Ocean likely represents a new species of Capsala Bosc, 1811 and that the Kayis et al. 2010 record from the Aegean Sea likely depicts a species of Capsaloides Price, 1938.

The myxozoan fauna of Fundulus diaphanus (Cyprinodontidae) from freshwater localities in eastern North America: prevalence, community structure, and geographic distribution.

Membership and richness of infracommunities and component communities of myxozoan fauna of the banded killifish (Fundulus diaphanus) from freshwater localities in Ontario, Quebec, New York State, New Brunswick, Nova Scotia, and Maryland were studied. Five species of parasites were found: Myxobolus diaphanus (Fantham, Porter, and Richardson, 1940) (connective tissue throughout the body and head), Myxobolus funduli (Kudo, 1918) (interlamellar), Myxobolus neurophilus (Guilford, 1963) (optic tectum of the brain), Myxobolus sp. (connective tissue, typically adjacent to vertebrae), and Sphaerospora sp. (kidney tubules). The most abundant species locally and regionally was M. diaphanus, occurring at prevalences of 14.2 to 93.3% at 6 of 9 localities. Myxobolus funduli and Myxobolus sp. were at 3 and 2 localities respectively, while M. neurophilus and Sphaerospora each occurred at single localities. Four of the 5 myxozoans appear to be specific to fundulids, the exception being M. neurophilus, which is typically a parasite of Perca flavescens. Mean infracommunity richness was 0-1.2. Component community richness was 0-3 species. The fauna is similar in composition to that described from the spottail shiner (Notropis hudsonius) in the Great Lakes in being dominated by histozoic myxobolids and in having maximum prevalence at any single locality correlate positively with geographical distribution. Moreover, mean infracommunity richness was correlated with percentage of hosts infected with any species at a locality, and maximum infracommunity richness was correlated with component community richness. Probably because fewer species of myxozoans of fundulids occur in the regional pool, myxozoan communities encountered in the present study are generally less rich than those described from N. hudsonius. It appears that dispersal of relatively resilient myxospores through such a mechanism as piscivory effectively distributes these parasites over the landscape, while the more delicate actinospores serve to ensure colonization by amplifying species' prevalence at a specific locality and thereby contributing to initial establishment. As such, these types of myxozoans, though they are autogenic, having their entire life cycle normally completed within the aquatic environment, behave more like allogenic parasites that rely on birds and mammals as definitive hosts.