Diplophrys parva, Anderson & Cavalier-Smith, 2012

Anderson, O. Roger & Cavalier-Smith, Thomas, 2012, Ultrastructure of Diplophrys parva, a New Small Freshwater Species, and a Revised Analysis of Labyrinthulea (Heterokonta), Acta Protozoologica 51 (4), pp. 291-304 : 300

Novelty of Diplophrys parva

The ATCC 50360 isolate that we name Diplophrys parva n. sp., differs substantially in size, shape, and/ or fine structural features from published descriptions of D. archeri and A. marina . It is essentially the same length as A. marina , but only about half the size of D. archeri that typically has a much larger refractive granule (often filling over half the diameter of the cell) and larger cell size (10 µm or larger) compared to D. parva (5–7 µm). However, the original description of D. archeri stated only that it was exceedingly minute and gave no size measurement or illustration. Archer, as described in Barker (1868), first stated that its average size was 1/ 2000 inch, i.e. 12.7 µm. As Archer was present at the meeting the previous year where D. archeri was first shown in public, described and its name published, we consider that this should be accepted as the average size of D. archeri . D. parva is about half the size of D. archeri , a sufficiently large difference to make it unwise to treat them as one species. As many different species have probably been lumped under that name and most descriptions may relate to others, different sizes given in some later studies should not be attributed to D. archeri . Despite their somewhat similar size and general appearance, there is no possibility of confusing D. parva and A. marina . One is marine and the other freshwater; as they have ultrastructurally different scales and their rDNA sequences are radically different, two genera are merited.