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Jaws virgate, symmetrical. All four part present, fulcrum
is long, asymmetric and the rami pointed. Piercing and

Without foot. Cuticle thin, transparent,
not usually retaining its shape well after preservation.
Body with 12 blades or feathers in 4 groups of 3 blades,
groups dorsoventrally and 2 groups ventro-laterally.

Planktonic and, some epiphytic on roots of Eichornia,
Water hyacinth (
Arora and Mehra, 2003c). See Hollowday (2002)
for a key to the genus.

         - Laguna de Bay.
       Polyarthra sp.


66 a. Blades feather-like, up to 30 μm broad. Length of blades
equal to or less than body length........................


66 b. Blades serrated sword-shaped, only up to 15 μm broad.
Length of blades longer than length of body
Size 90-120
μm. Ventral finlets present
(can only be seen for sure in lateral view.)
pH range 4.2-8.6. In eutrophic waters. (Hollowday, 2002)
- IRRI rice field.
   Polyarthra cf. dolichoptera IDELSON, 1925

67 a. Blades 20-30 μm broad. (should be measured by a
micrometer on a flat blade.)
Length of blades
less than length of body.
No ventral finlets. Size 150-170
Planktonic in lakes and occasionally in big ponds.
Eurythermic and eurytrophic. pH 3.5-9
(Hollowday, 2002).

- Lake Danao
   Polyarthra major, BURCKHARDT, 1900

67 b. Blades 8-20 μm broad, but variable, grading
from father-shape to narrow sword-shape
(narrowing the P. dolichoptera shape).
Length of blades equal to or less than body length.
Ventral finlets present. Size 100-150
Feeds only on algae (Diatoms and cryptomonads,
as in Lake Lanao (Lewis 1979)).
Planktonic in lakes,
ponds and reservoirs of eurytherm and oxygen rich
types, pH 4.9-8.7.
Indicator of mesotrophic waters
(Sládeček 1983)
. Abundance was higher in the
Northern basin of Taal Lake, than the Southern
basin, probably caused by the eutrophication
effect of the fish gages in the area
(Papa et al. 2011b).
Laguna de Bay, Pasig River, La Mesa Dam, Lake Mainit,
  Lake Lanao, Paoay Lake, Taal Lake.
   Polyarthra vulgaris, (CARLIN, 1943)
Syn.: Polyarthra trigla vulgaris SUDZUKI 1964
      [1973, 1977, 1978a+b, 1979b,
      1980, 1984a, 1986a, 2008b, 2009a, 2011b+c, 2012a)]

P. vulgaris from Laguna de Bay


To 68 a.