Turbellarian taxonomic database
Hooge M.D. & Rocha C.E.F. 2006 (citation) - P. 11 "Our specimens are remarkably similar to Philactinoposthia
stylifera(Westblad, 1946), which occurs rarely at 10–30 m depth from Gullmarfjord, Sweden, and as such, should
be considered a subspecies. Our specimens are of similar size to P. stylifera and have a copulatory organ that
is similarly constructed and positioned. P. stylifera has a female gonopore, which is absent in our specimens,
but the pore is likely to be facultative and is probably present at other stages of its life history.
Additionally, Westblad (1946) describes large rhabdoids, 20 µm in length, for P. stylifera, while our
specimens have very small, rod-shaped rhabdoids that are only 7 µm in length.
In Dörjes and Karling’s (1975) review of the turbellarian type material held at the Swedish Museum of Natural
History, they report that, contrary to the description of Westblad (1946), P. stylifera has a true seminal
vesicle positioned at the proximal end of the penis needles. We are skeptical of this report in light of
Westblad’s (1946) original description, in which he clearly shows paired strands of sperm from the testes
positioned well posterior and lateral to the proximal end of the penis needles and converging upon the needles
at the middle of their length. This configuration is the same as in our specimens, and as such, we continue to
regard P. stylifera as lacking a true seminal vesicle."