Pseudocollinia brintoni gen. nov., sp. nov. (Apostomatida: Colliniidae), a parasitoid ciliate infecting the euphausiid Nyctiphanes simplex

Abstract

A novel parasitoid ciliate, Pseudocollinia brintoni gen. nov., sp. nov. was discovered infecting the subtropical sac-spawning euphausiid Nyctiphanes simplex off both coasts of the Baja California peninsula, Mexico. We used microscopic, and genetic information to describe this species throughout most of its life cycle. Pseudocollinia is distinguished from other Colliniidae genera because it exclusively infects euphausiids, has a polymorphic life cycle, and has a small cone-shaped oral cavity whose left wall has a field of ciliated kinetosomes and whose opening is surrounded on the left and right by 2 'oral' kineties (or ciliary rows) that terminate at its anterior border. Two related species that infect different euphausiid species from higher latitudes in the northeastern Pacific Ocean, Collinia beringensis Capriulo and Small, 1986, briefly redescribed herein, and Collinia oregonensis Gómez-Gutiérrez, Peterson, and Morado, 2006, are transferred to the genus Pseudocollinia. P. brintoni has between 12 and 18 somatic kineties, and its oral cavity has only 2 oral kineties, while P. beringensis comb. nov. has more somatic kineties, including 3 oral kineties. P. oregonensis comb. nov. has an intermediate number of somatic kineties. P. beringensis comb. nov. also infects Thysanoessa raschi (a new host species). SSU rRNA and cox1 gene sequences demonstrated that Pseudocollinia ciliates are apostome ciliates and that P. brintoni is different from P. beringensis comb. nov. High densities of rod-shaped bacteria (1.7 µm length, 0.2 to 0.5 µm diameter) were associated with P. brintoni. After euphausiid rupture, high concentrations of P. brintoni and bacteria cluster to form 3 to 6 cm long filaments where tomites encyst and transform to the phoront stage; this is a novel place for encystation. P. brintoni may complete its life cycle when the euphausiids feed on these filaments.KEY WORDS: Euphausiids · Ciliates · Apostomatidae · Collinia · cox1 · SSU rRNA · MexicoResale or republication not permitted without written consent of the publisher

Ciliate species diversity and host-parasitoid codiversification in Pseudocollinia infecting krill, with description of Pseudocollinia similis sp. nov.

“…This has resulted in the description of 2 additional species of ciliates and an analysis that placed these 3 ciliate species in the new apostome genus Pseudocollinia (P. beringensis, P. ore gonensis, and P. brintoni; Gómez-Gutiérrez et al 2006. Mitochondrial cytochrome c oxidase sub unit 1 (cox1) and small subunit rRNA (SSU rRNA) gene sequences of the most recently described species (P. brintoni) and the type species P. beringensis demonstrated that they are apostomate ciliates (Gómez-Gutiérrez et al 2012). Here, we present an additional contribution in this series describing the new species P. similis sp.…”

Histophagous ciliate Pseudocollinia brintoni and bacterial assemblage interaction with krill Nyctiphanes simplex. II. Host responses

“…Most infected krill collected from the Bering Sea (Thysanoessa spp. ; 14−30 mm; Lynn et al 2014), the US west coast (Euphausia pacifica and T. spinifera; 15−28 mm; , and the southwestern coast of Baja California Peninsula and the Gulf of California, Mexico (N. simplex;9− 19.2 mm;Gómez-Gutiérrez et al 2012a) have been adult females (from first maturity to full maturity). Pseudocollinia does not infect exclusively female krill; Pseudocollinia-infected males have also been reported, albeit at very low prevalences (Capriulo et al 1991, Gó -mez-Gutiérrez et al 2003.…”

“…Although fatty acid composition was determined in infected krill at 5 phases (Table 1), we combined them to increase sample size (n = 7) and estimate mean and 95% confidence intervals of the mean of the 12 most abundant fatty acid lipids. Pseudocollinia life phases are illustrated by , 2012a. During the cruises, control (healthy females) and infected krill specimens were placed in sealed containers (cryovials), frozen, transported in liquid nitrogen, and stored at −80°C until needed for biochemical analyses.…”

“…Other protists, such as apostome ciliates of the genus Pseudocollinia, can cause epizootic events of adult krill populations (Gómez-Gutiérrez et al 2003). Research on histophagous ciliates infecting krill has mostly focused on taxonomic perspectives and biology (Capriulo & Small 1986, Capriulo et al 1991, Stankovic & RakusaSuszczewski 1996, Gómez-Gutiérrez et al 2003, 2010a, 2012a, Lynn et al 2014. Considerably less is known about aspects of Pseudocollinia ecology, parasite−host interactions, and physiological and biochemical composition between healthy and Pseudocollinia-infected krill.…”

“…However, little is known about the immune system response and physio logical changes of krill (Zhao et al 2011, Seear et al 2012, resulting in a poor and fragmented understanding about the effect of pathogens and para sites on euphausiids. Here we explored how the fatty acids and oxidative stress enzymes of N. simplex respond to histophagous ciliate infections through the different endoparasitic life phases that typically last a few days , 2012a.…”