Extended Observation Descriptions
Extended Observation Description on Ptygura kostei
Ptygura kostei José de Paggi, 1996
Ptygura kostei in a Freshwater Aquarium
Ptygura kostei on Java moss (Taxiphyllum barbieri) filaments from a freshwater aquarium.
On the Java moss filaments, Ptygura kostei was found attached to its axils.
Fig. 1: Ptygura kostei on a Java moss (Taxiphyllum barbieri) filament. The somatic body is retracted, the characteristic nuchal fork can be seen with three of the four hooks of approximately equal size. |
The form group Ptygura furcillata–elsteri–kostei is characterized by the presence of a nuchal fork. Ptygura kostei was first described by Koste as a forma of the species Ptygura elsteri. Susana Beatriz José de Paggi redescribed it as a separate species in 1996 on the grounds that the four hooks on the nuchal fork are equal in size, while in P. elsteri they form unequal-sized pairs.
José de Paggi, Susana. (1996). Rotifera (Monogononta) diversity in subtropical waters of Argentina.
http://dx.doi.org/10.1051/limn/1996019. 32. 10.1051/limn/1996019.
Fig. 2, 3: The three optical sections in Fig. 2 show the nuchal fork with its base rod (double arrowhead, also Fig. 3), the trophi (arrow) and the fully opened corona (double headed arrow). The focal planes are below = dorsal side of the rotifer (left image), in the middle of the body (middle image) and above = ventral (right image). |
Fig. 3: Fully expanded rotifer in lateral view in median optical section showing base rod and 3 of 4 hooks of the nuchal fork (double arrowhead), trophi (arrow) and fully opened corona. The inset above right shows the rotifer in ventral view with fully retracted somatic body, which allows an unimpeded view of the four hooks of the nuchal fork. the nuchal fork with its base rod. |
© Wolfgang Bettighofer,
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