Turbellarian taxonomic database
Philocelis robrochai Notes
Hooge M.D. & Rocha C.E.F. 2006 (citation) - P. 45 "Species of the genus Philocelis are united in having the
vagina positioned posterior to the male copulatory organ, a seminal bursa with attached bursal nozzle, and a
male copulatory organ composed of a muscular penis-sac surrounding sclerotized stylets. Although the penis
stylet of P. robrochai is more compact than that of P. brueggemanni Hooge and Tyler, 2003, P. cellata Dörjes,
1968, and P. karlingi (Westblad, 1946), which have widely spaced stylet needles, the overall organization of
the male copulatory organ appears to be homologous. Preliminary analysis of both cytochrome oxidase I and 18S
rDNA molecular sequence data support a strong relationship between P. robrochai and P. brueggemanni
(unpublished data). Interestingly, 18S sequence data also supports a close relationship between Philocelis
species and Philactinoposthia saliens (Graff, 1882) (Actinoposthiidae)—a relationship that is further
supported by similarities in sperm ultrastructure (Petrov et al. 2004). Several species of Philactinoposthia
appear to have male copulatory organs with a similar composition to that of Philocelis, and given that the
Otocelididae has been shown to be non-monophyletic (Hooge & Tyler 2005), any future revision of the
Otocelididae should include an examination of the relationship of these two genera. "
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