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     Without foot. Cuticle thin, transparent, 
not usually retaining its shape well after 
preservation. Body with long spines, 2 anterior 
and 1 (Filinia) or 2 (Tetramastix) posterior 
spines. Planktonic.
The separation in two genera (Filinia and 
) based on the number of posterior 
spines might not be valid since intermediates 
are found (Ruttner­Kolisko 1972).

The genus is abundance among the plankton in polluted
biotopes like Pasig River (2009a). Prefer alkaline
waters (
Sládeček 1983).


Two posterior spines developed. One well developed
(200 μm)
one more or less reduced (= spine).
Lateral spines broad-based
, club-like, and
only slightly longer the body. Body
. Size 150-200 μm. Shows affinity for
cryptomonads, cyanobacteria (blue greens)
and dinoflagellates
in Lake Lanao (Lewis 1979).
Warm stenotherm (25-38oC), pH 7.3-8.2,
conductivity 50-1,450 μS cm-1. Planktonic
in lakes and ponds. Indicator of
waters (Sládeček 1983). Stenohaline, cannot
handle a wide fluctuation in the
salt content
of water. Common.
- Laguna de Bay, La Mesa Dam, Calibato Lake, 
  Lake Lanao, Paoay Lake.
   Filinia opoliensis, (ZACHARIAS, 1898)
    (syn. Tetramastix opoliensis)
             [1941a, 1974, 1977, 1978a+b, 1979b
             1980, 1984a, 1986a, 2008b, 2011b+c]

F. opoliensis from Laguna de Bay

F. opoliensis
(Photo Rey Donne S. Papa, 2007)



71 b Only one posterior spine........................72


72 a. Only one movable posterior spine, arising from the ven­tral
surface. Spines not thickened at the base. Lateral spines
much longer than body, but less than 4 times than the body
Inserted more than 10 μm from terminal end of body.
Size of body 150-250 μm, lateral spines 300-710 μm, terminal
spine 125-315 μm.
Lake forms usually with longer spines than
pond form. Form limnetica (or species Filinia limnetica
(ZACHARIAS 1893)) if spines 4 times longer than body or more.

Feed on detritus and bacteria, with a particle size less than
10 μm. Warm stenotherm 23-31oC, pH 7.4-8.1, and conductivity
180-1,600 μS cm-1, salinity 0-0.50/00 but stenohaline, so it
cannot handle a wide fluctuation in the salt content of water.
In shallow, eutrophic lakes, fishponds, village ponds. May
dominate the rotifer community.
Indicator of eutrophic and
polytrophic 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, Sampaloc Lake, Taal Lake.
   Filinia longiseta (EHRENBERG, 1834)
    (syn. Triarthra longiseta)

    (syn.  F. L. form limnetica

      Filinia limnetica (ZACHARIAS 1893))
             [1941a, 1974, 1980, 1984a, 1999, 2011b+c]

F. longiseta from Laguna de Bay

72 b.  Small, cylindrical-oviform body, posterily
rounded but may be fusiform in contracted
individuals. Posterior spine inserted 4-10 μm
from terminal end of body, slightly thickened
at base.
Like F. terminalis. Body length
120-140 μm. Lateral spines 265-350 μm.

Terminal spine 180-290 μm. 
In eutrophic
lakes and rice fields (
Shiel and 
Sanoamuang, 1
993, Tuyor and Segers, 1999)
- IRRI rice field.
   Filinia novaezealandiae, SHIEL AND SANOAMUANG, 1993

72 c. Caudal seta inserted terminally, Body narrow-elongate fusiform.
Body relatively short, usually shorter than 200
Trophi with 16-17/17-19 unci.
- Laguna de Bay.
   Filinia pejleri HUTCHINSON, 1964


Other pantropic species of Filinia from the neighbourhoods
Sanoamuang, 2002):

Lateral setae inserted at the point near middle part of body.
 - Not recorded from the Philippines.
   Filinia camasecla MEYERS, 1938

Lateral setae short.
- Not recorded from the Philippines
   Filinia brachiata (ROUSSELET, 1901)


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