Hydrobiologia 298: 125-132, 1995.
D. Belk, H. 1. Dumont & G. Maier (eds), Studies on Large Branchiopod Biology and Aquaculture II.
©1995 Kluwer Academic Publishers.
125
Review of Colombian Conchostraca (Crustacea) - ecological aspects and life
cycles - families Lynceidae, Limnadiidae, Leptestheriidae and
Metalimnadiidae
Ewald W. Roessler
Departamento de Ciencias Biol6gicas, Universidad de los Andes, A.A. 4976, Bogota, Colombia, South America
Key words: conchostraca, South America, Colombia, ecology, distribution
Abstract
This study gives an overview of our current knowledge of the ecology and distribution patterns of Colombian
conchostracans. Colombian euphyllopods are generally restricted to the warm tropical lowlands. Only Cyclestheria
hislopi can be found year-round in larger semipermanent and permanent waters and living sympatrically with
abundant predators, such as planktivorous fish. The other conchostracans are restricted to the typical habitat of
temporary waters. Eulimnadia magdalenensis is especially adapted to very short -term temporary ponds in relatively
arid zones and E. colombiensis prefers somewhat cooler ponds of a longer duration. The two species can be found
sympatrically in intermediate climatic conditions. A third form, Eulimnadia cf geayi cohabits with the two other
species in the lower Magdalena Valley, its ecological role is not clear. Limnadia orinoquiensis is the selvatic
substitute of the open savannah conchostracan fauna (mainly Eulimnadia forms) living in pools in forest clearings
in the vicinity of the Upper Orinoco.
Four species of Lynceidae were found, two Lynceus and two Paralimnetis. Their distribution patterns are not yet
clear, they prefer smaller temporary ponds of moderated temperatures. Two undescribed species of Leptestheria
were found, one restricted to the banks of the Orinoco and the other to one locality in the upper Magdalena Valley,
living in ponds with a muddy bottom. Metalimnadia serratura was found in special rock pools of the Guiana Shield
in the vicinity of the Orinoco, cohabiting with several other conchostracan species, with differential adaptations to
very high water temperatures.
Materials and methods
The studies were carried out from 1977 through 1993
in the tropical lowlands of Colombia. Specimens were
collected with dip nets with mesh widths from 65 to
125 j.Lm, according to the developmental stages wanted. Specimens were preserved in 4% to 8% formalin
or 90% ethyl alcohol.
For preliminary developmental studies, some laboratory cultures were made in small aquaria from 250ml to 10-1 capacity. Mixed green microalgae cultures,
supplemented with powdered commercial fish food for
aquarium fish, were used as food.
For histological studies, special fixatives were
used, mainly solutions of Bouin. Permanent mountings of certain specimens and of histological sections
were made by inclusions in artificial balsam.
General ecological aspects
Euphyllopods are generally considered to have undergone specific adaptations to live in temporary waters
and normally occur in the early phases of community
succession. This particular adaptation is believed to
reflect a specific form of evasion to avoid confrontations with predators. The relatively large euphyllopods
apparently have not developed very effective defensive strategies other than the relatively weak carapace.
Confrontations with predators eventually lead to the
extinction of conchostracan populations, except for
Cyclestheriidae.
Nevertheless, euphyllopods are not completely
defenseless. The bivalved carapace of conchostracans
provides a certain protection and the heavily armed
telson, as well as the strong and spiky second anten-
D. Belk, H. 1. Dumont & G. Maier (eds), Studies on Large Branchiopod Biology and Aquaculture II.
©1995 Kluwer Academic Publishers.
125
Review of Colombian Conchostraca (Crustacea) - ecological aspects and life
cycles - families Lynceidae, Limnadiidae, Leptestheriidae and
Metalimnadiidae
Ewald W. Roessler
Departamento de Ciencias Biol6gicas, Universidad de los Andes, A.A. 4976, Bogota, Colombia, South America
Key words: conchostraca, South America, Colombia, ecology, distribution
Abstract
This study gives an overview of our current knowledge of the ecology and distribution patterns of Colombian
conchostracans. Colombian euphyllopods are generally restricted to the warm tropical lowlands. Only Cyclestheria
hislopi can be found year-round in larger semipermanent and permanent waters and living sympatrically with
abundant predators, such as planktivorous fish. The other conchostracans are restricted to the typical habitat of
temporary waters. Eulimnadia magdalenensis is especially adapted to very short -term temporary ponds in relatively
arid zones and E. colombiensis prefers somewhat cooler ponds of a longer duration. The two species can be found
sympatrically in intermediate climatic conditions. A third form, Eulimnadia cf geayi cohabits with the two other
species in the lower Magdalena Valley, its ecological role is not clear. Limnadia orinoquiensis is the selvatic
substitute of the open savannah conchostracan fauna (mainly Eulimnadia forms) living in pools in forest clearings
in the vicinity of the Upper Orinoco.
Four species of Lynceidae were found, two Lynceus and two Paralimnetis. Their distribution patterns are not yet
clear, they prefer smaller temporary ponds of moderated temperatures. Two undescribed species of Leptestheria
were found, one restricted to the banks of the Orinoco and the other to one locality in the upper Magdalena Valley,
living in ponds with a muddy bottom. Metalimnadia serratura was found in special rock pools of the Guiana Shield
in the vicinity of the Orinoco, cohabiting with several other conchostracan species, with differential adaptations to
very high water temperatures.
Materials and methods
The studies were carried out from 1977 through 1993
in the tropical lowlands of Colombia. Specimens were
collected with dip nets with mesh widths from 65 to
125 j.Lm, according to the developmental stages wanted. Specimens were preserved in 4% to 8% formalin
or 90% ethyl alcohol.
For preliminary developmental studies, some laboratory cultures were made in small aquaria from 250ml to 10-1 capacity. Mixed green microalgae cultures,
supplemented with powdered commercial fish food for
aquarium fish, were used as food.
For histological studies, special fixatives were
used, mainly solutions of Bouin. Permanent mountings of certain specimens and of histological sections
were made by inclusions in artificial balsam.
General ecological aspects
Euphyllopods are generally considered to have undergone specific adaptations to live in temporary waters
and normally occur in the early phases of community
succession. This particular adaptation is believed to
reflect a specific form of evasion to avoid confrontations with predators. The relatively large euphyllopods
apparently have not developed very effective defensive strategies other than the relatively weak carapace.
Confrontations with predators eventually lead to the
extinction of conchostracan populations, except for
Cyclestheriidae.
Nevertheless, euphyllopods are not completely
defenseless. The bivalved carapace of conchostracans
provides a certain protection and the heavily armed
telson, as well as the strong and spiky second anten-