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Journal of Micropalaeontology An open-access journal of The Micropalaeontological Society
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Volume 25, issue 2
J. Micropalaeontol., 25, 189–190, 2006
https://doi.org/10.1144/jm.25.2.189
© Author(s) 2006. This work is distributed under
the Creative Commons Attribution 4.0 License.
J. Micropalaeontol., 25, 189–190, 2006
https://doi.org/10.1144/jm.25.2.189
© Author(s) 2006. This work is distributed under
the Creative Commons Attribution 4.0 License.

  01 Nov 2006

01 Nov 2006

Ankumia van Veen, 1932: a valid name, but a flawed generic concept (Ostracoda, Platycopina, Cytherelloidea)

Peter J. Jones Peter J. Jones
  • Department of Earth and Marine Sciences, The Australian National University, Canberra ACT 0200, Australia (e-mail: )

Abstract. Recent study of the syntype material of the type species of the monotypic genus Ankumia van Veen, 1932 (A. bosqueti van Veen, 1932) confirmed a pathological retention of moults, expressed by multilayered ridge-like structures, used for the original diagnosis of the genus (Jones, 2003). For this reason, it was proposed that the genus Ankumia should be abandoned as a nomen dubium in favour of Platella Coryell & Fields, 1937. This interpretation was challenged by Malz & Lord (2004), who saw no reason to treat Ankumia as nomen dubium and, acknowledging the unequivocal cytherellid nature of the species, posed and addressed two taxonomical questions: (1) do pathological individuals of cytherellids justify specific and/or generic ranking?; (2) why should Ankumia be abandoned in favour of Platella?

In addressing their first question, Malz & Lord (2004) correctly answered in the negative. However, they claimed that ‘... demonstration of a corresponding “normal” species (including “pathological individuals”) among the associated cytherellids is wanting’. The author disagrees with this statement because he described and illustrated two morphological shell-types among the specimens assigned as syntypes of Ankumia bosqueti in the van Veen/Bonnema collection. They are the ‘Cytherella shell-type’ (Jones, 2003, pl. 1, figs 2–8) and the ‘Ankumia shell-type’ (Jones, 2003, pl. 1, fig. 1; pl. 2 figs 1–14), which correspond to the ‘normal’ species, and to the pathological individuals of that species, respectively. The Ankumia shell-type possesses concentric ribs that become progressively thinner from the adult to the juvenile stages. Of the 22 syntypes studied, 13 . . .

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