OXYMONADIDA

Description

by GUY BRUGEROLLE and JOHN J. LEE Oxymonads are intestinal parasitic flagellates with a cell basically comprising one karyomastigont rows composed of one nucleus, four flagella arranged in two pairs, a preaxostylar lamina, and a paracrystalline axostyle (several genera have nema two to several karyomastigonts)(Fig . 1). One or more of the anterior flagella is recurrent or adhering to the body surface. The pairs of basal bodies are separated by a preaxostylar I ami n a of a composite paracrystalline structure (Figs. 2,3,4a,b) . The crystalline axostyle , originating from or near the anterior preaxostylar lamina , is composed of parallel rows of interlinked microtubules (Fig. 4c) . An anterior row of microtubules or pelta is generally present (Fig. 2). Several species have developed an anterior expansion named holdfast (microfibrillar) and rostellum (microtubular) to attach to the chitinous intima of the insect host intestine (Figs. 1 ,3 ,4d,e) . No cytostome, nutrition by phagocytosis and pinocytosis; several xylophagous species ; glycogen is the reserve . They reproduce by binary fission and the mitosis is of the closed type with an intranuclear spindle (Cleveland , 1938, Hollande anb Carruette-Valentin , 1970b). Parental axostyle depolymerizes during division . Sexual OXYMONADIDA processes are described in some species . A II 2. The two pa species are endocommensal or symbiotic and live in preaxostylar the gut of insects except one Monocercomonoides 3. Axostyle c which also lives in the gut of vertebrates. microtubules; Transmission by cysts or trophic form. 4. No cytosto Five families reported: Polymastigidae, pinocytosis. Saccinobaculidae, Oxymonadidae, Pyrsonymphidae, 5. Closed mit Streblomastigidae , (Grasse, 1952, Vickerman , 1982) . The Polymastigidae have the basic characters of the group and seem more primitive. The species of the other four families live in term ites and in the wood-eating roach Cryptocercus, and they have developed adaptations for host attachment (holdfast, rostellum), contractile axostyle, complex life cycle including sexual processes. The list of oxymonad species living in termites and in the roach Cryptocercus punctulatus is given by Yamin (1979a) . The light microscopic coverage of the group is found in Grasse (1952); ultrastructural features in Brugerolle (1991 ). Monocercomono bodies/flagel preaxostylar (A) . The pel microtubules flagellum (R) ARTI D 1. No attachm subfamily : A. Polymastix. B. Saccinobacu/us C. Pyrsonympha. D. Streblomastix. E. Oxymonas. (G . no attache Brugerolle) 1'. With an a rostellum) Key Characteristics intestine 1. Motile cells contain one or more karyomastigonts 2. With a sle each with four flagella typically arranged in two ... Family sepa rated pairs . .......... irs of basal bodies separated by a lamina. omposed of parallel rows of contractile in some genera. me; nutrition by phagocytosis or osis with intranuclear spindle. ganization of the mastigont system of ides: the two pairs of basal la (B ,B') are separated by the lamina (P) from which arise the axostyle la (Pe) caps the nucleus, and a row of (arrow) is adjacent to the recurrent . (From Brugerolle and Joyon, 1973) FICIAL KEY TO FAMILIES AND SELECTED GENERA b Y

Type species

Figures

Raw text

by GUY BRUGEROLLE and JOHN J. LEE
Oxymonads are intestinal parasitic flagellates with
a cell basically comprising one karyomastigont
rows composed of one nucleus, four flagella arranged in
two pairs, a preaxostylar lamina, and a
paracrystalline axostyle (several genera have
nema two to several karyomastigonts)(Fig . 1). One or
more of the anterior flagella is recurrent or
adhering to the body surface. The pairs of basal
bodies are separated by a preaxostylar I ami n a
of a composite paracrystalline structure (Figs.
2,3,4a,b) . The crystalline axostyle , originating
from or near the anterior preaxostylar lamina , is
composed of parallel rows of interlinked
microtubules (Fig. 4c) . An anterior row of
microtubules or pelta is generally present (Fig.
2). Several species have developed an anterior
expansion named holdfast (microfibrillar) and
rostellum (microtubular) to attach to the
chitinous intima of the insect host intestine (Figs.
1 ,3 ,4d,e) . No cytostome, nutrition by phagocytosis
and pinocytosis; several xylophagous species ;
glycogen is the reserve . They reproduce by binary
fission and the mitosis is of the closed type with an
intranuclear spindle (Cleveland , 1938, Hollande
anb Carruette-Valentin , 1970b). Parental
axostyle depolymerizes during division . Sexual
OXYMONADIDA
processes are described in some species . A II 2. The two pa
species are endocommensal or symbiotic and live in preaxostylar
the gut of insects except one Monocercomonoides 3. Axostyle c
which also lives in the gut of vertebrates. microtubules;
Transmission by cysts or trophic form. 4. No cytosto
Five families reported: Polymastigidae, pinocytosis.
Saccinobaculidae, Oxymonadidae, Pyrsonymphidae, 5. Closed mit
Streblomastigidae , (Grasse, 1952, Vickerman ,
1982) . The Polymastigidae have the basic
characters of the group and seem more primitive.
The species of the other four families live in
term ites and in the wood-eating roach
Cryptocercus, and they have developed adaptations
for host attachment (holdfast, rostellum),
contractile axostyle, complex life cycle including
sexual processes. The list of oxymonad species
living in termites and in the roach Cryptocercus
punctulatus is given by Yamin (1979a) .
The light microscopic coverage of the group is found
in Grasse (1952); ultrastructural features in
Brugerolle (1991 ).
Monocercomono
bodies/flagel
preaxostylar
(A) . The pel
microtubules
flagellum (R)
ARTI
D
1. No attachm
subfamily : A. Polymastix. B. Saccinobacu/us C.
Pyrsonympha. D. Streblomastix. E. Oxymonas. (G . no attache
Brugerolle) 1'. With an a
rostellum)
Key Characteristics intestine
1. Motile cells contain one or more karyomastigonts 2. With a sle
each with four flagella typically arranged in two ... Family
sepa rated pairs . ..........
irs of basal bodies separated by a
lamina.
omposed of parallel rows of
contractile in some genera.
me; nutrition by phagocytosis or
osis with intranuclear spindle.
ganization of the mastigont system of
ides: the two pairs of basal
la (B ,B') are separated by the
lamina (P) from which arise the axostyle
la (Pe) caps the nucleus, and a row of
(arrow) is adjacent to the recurrent
. (From Brugerolle and Joyon, 1973)
FICIAL KEY TO FAMILIES AND
SELECTED GENERA
b
Y