The molecular profile of Acanthogyrus (Acanthosentis) kashmirensis from the Indian subcontinent

Parasites of Moroccan desert Coptodon guineensis (Pisces, Cichlidae): transition and resilience in a simplified hypersaline ecosystem

Sebkha Imlili (Atlantic Sahara) is a salt flat with over 160 permanent holes of hypersaline water generated in the Holocene and inhabited by euryhaline organisms that are considered to be relics of the past, including the cichlid fish Coptodon guineensis. We surveyed the fish parasites four times over one year, to i) identify the parasites, and ii) determine possible seasonality in infection patterns. Over 60% of the fish were infected by one to three helminths: an acanthocephalan in the intestine and two digenean metacercariae in the kidney, spleen, liver, muscle, and mesenteries. The acanthocephalan Acanthogyrus (Acanthosentis) cf. tilapiae was identified morphologically and molecularly; only one digenean (the heterophyid Pygidiopsis genata) could be identified molecularly. Both identified parasites were present throughout the sampling periods; the unidentified metacercariae were present only in summer and fall. Mean intensities, but not prevalence of infection by the acanthocephalan, reflected a biannual pattern of transmission. Infection accrued with fish size, possibly due to cannibalism. Because the water holes include only a few invertebrates, the intermediate hosts of these parasites can be inferred to be the gastropod Ecrobia ventrosa for the digeneans and either the copepod Cletocamtpus retrogressus or the ostracod Cyprideis torosa for the acanthocephalan. This ecosystem appears stable and provides a window into the past, as the acanthocephalan likely switched from freshwater tilapia to C. guineensis when the Sebkha formed. However, this is a vulnerable environment where the survival of these parasites depends on interactions maintained among only very few hosts.

New perspectives of Microsentis wardae Martin & Multani, 1966 (Acanthocephala: Neoechinorhynchidae) from Gillichthys mirabilis Cooper in California, with scanning electron microscopy images and energy dispersive X-ray analysis

Fully developed, sexually mature small male and female acanthocephalans, Microsentis wardae Martin & Multani, 1966 (Neoechinorhynchidae) reaching only 2.25 mm and 2.42 mm, respectively, were collected from the rectum of longjaw mudsuckers, Gillichthys mirabilis Cooper, in the salty marches of Anaheim Bay and San Diego Bay, California. Our specimens were half the size of those reported in the original description from the same host in Scammon's Lagoon over 700 km to the south. The ratio of proboscis and receptacle size to trunk size was markedly higher in our specimens compared to the larger specimens measured in the original description. The anatomy of all structures in our specimens from Anaheim Bay was comparable to that of the larger Scammon's Lagoon specimens that have apparently realized more growth in the Scammon's Lagoon. We have observed more structures that are not reported in the original description, especially evident from our scanning electron microscopy images, which are not possible to observe in the original line drawings. In our specimens, the micropores were unusually widely spaced and the energy dispersive X-ray analysis showed longitudinal hook sections with high levels of sulphur and phosphorus and moderate levels of calcium, but the whole hooks showed highest levels of sodium and magnesium - the biochemical hook signature of this species. Sequences of the small subunit (18S) of the nuclear ribosomal DNA were generated and compared with acanthocephalan sequences available from GenBank. As M. wardae comprises a monotypic genus, therefore, phylogenetic analyses inferred from the 18S gene showed its relationship with other species of closely related genera of Eoacanthocephala. This is the first report of molecular data of M. wardae.