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Leuckarti group. Hairless forms.

·         Without patterns of hair on 5th segment. 

·        Caudal rami without hairs (Alekseev, 2002a).

131 a. Copulatory duct sinuously curved..............................132.

131 b. Copulatory duct not sinuously curved..........................133.

 

132 a. Copulatory duct sinuously curved. Without patterns of hair on 5th
segment. Caudal rami without hairs Copulatory duct sinuously curved.
Planktonic species. Egg sacs large, divergent. Food infusorians,
young stages of cladocerans, rotifers. Size 600-1000 μm. Size of
longest setae 270-390 μm. Eurytherm: l9-39o Celsius and occur in
pH 4.5-8.5. Dominating the zooplankton biomass and production in
Laguna de Bay together with Thermocyclops crassus in 1980
(Petersen, 1981e). Planktonic in ponds and lakes. The genus is
very common. The species, previously considered as a cosmopolitan,
is confined to the Palearctic area (Europe and the western part
of northern Asia). Thus, M. leuckarti is only a collect name,
and all records have to be revised.
Kiefer (1930a) notes that the material from Laguna de Bay, Luzon,
not is the form found in Europe, but a full different variety,
which is distributed widely in the tropics, and maybe should be
accepted as a subspecies. Kiefer (1981c) concluded this opinion,
while Papa and Hołyńska (2013)claimed that all records belong
to other species, probably Mesocyclops thermocyclopoides (see 138b),
e.g. in Laguna de Bay and Lake Naujan,La Mesa Dam, Lake Lanao, Paoay Lake,
Taal lake.
      Mesocyclops leuckarti, (CLAUS, 1857)
          [non M. Leuckarti s. str. 1928a,
           1930a, 1941a, 1978a+b,1980, 1984a,

                  1986a, 2008b, 2011a]

 
M. "leuckarti" Female from Laguna de Bay

133 a. Lateral arms of seminal receptacle relatively narrow.
Connecting plate on fourth pair of legs with large (length/width >> 1)
spines (prominences). Copulatory duct not sinuously curved. Anterior
margin of proximal part of seminal receptacle sinuate in middle.
Body size 1100-1700 μm. Prefer eutrophic ponds and lakes, but also
in marshes, ditches, creeks, artificial water containers, and wells
(Ueda & Reid, 2003a).
- Not recorded from the Philippines. Distributed in
  Central Asia, India, Sri Lanka, (Malaysia?), Indochina,
  China, Japan and United States
   Mesocyclops pehpiensis HU, 1943
     (syn. Mesocyclops Leuckarti pehpiensis HU, 1943)
     (syn. Mesocyclops ruttneri KIEFER, 1981)
             [1981c, 2002a, 2003a].

Mesocyclops sp. From Laguna de Bay

133 b. Lateral arms of seminal receptacle conspicuously wide.
Connecting plate on fourth pair of legs with large
(length/width >> 1) spines (prominences). Copulatory duct
not sinuously curved. Anterior margin of proximal part of
seminal receptacle arcuate in middle. Body size 1300-1700 μm.
In ponds, swamps, pools, shallow ditches, slow-current streams,
and littoral zone of lakes.
- Not recorded from the Philippines.
  Distributed in Australia, New Guinea, Java and Borneo
   Mesocyclops papuensis VAN DE VALDE, 1987
             [2003a].

134 a. Both 5th segment and caudal rami with hairs...................135.

134 b. Body only with one pattern of hairs..........................136.

 

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