Neotypification and ontogenesis of Leptopharynx costatus costatus Mermod, 1914.

Using standard methods, we studied the morphology and ontogenesis of a German Leptopharynx costatus costatus. This population makes two morphs: microstomes with a size of 40 × 25 μm, about 190 basal bodies, and 5 μm wide oral basket; and macrostomes with a size of 55 × 40 μm, about 264 basal bodies, and 15 μm wide oral basket. Because the identity is threatened, this population is designated as the neotype of L. costatus costatus. Ontogenesis is complex due to the preoral kineties and the postoral complex produced by kineties 9 and 10. Stomatogenesis is mixokinetal: the opisthe membranelles 1 and 2 are formed by the oral primordium, whereas membranelle 3 is produced by the posterior portion of somatic kinety 1. The nasse kinetosomes are generated by the anterior portion of the oral primordium. Preoral kineties 1 and 3 develop de novo, while kinety 2 originates by intrakinetal proliferation of kinety 8; preoral kinety 4 is produced by the postoral complex, thus being a somatic kinety. Kinety 6 has two anterior kinetids in line with kinety 7. These observations require changes in the descriptive morphology, support the classification of Leptopharynx into the Microthoracidae, and sustain the nonmonophyly of the Nassophorea.