Key to Families and Genera in the Rhizophydiales Based on Molecular Monophyly and Zoospore Ultrastructural Characters
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Each family and genus is a monophyletic group as demonstrated in phylogenetic analyses of molecular sequences.
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Each genus has a zoospore with a unique suite of ultrastructural characters.
Key to Families and Genera in the Rhizophydiales
To view an image of a representative zoospore, double click on the genus.
The numbers under each picture are the character states for the 14 ultrastructural characters compared.
A. Kinetosome and non-flagellated centriole each with a densely granular core.........
............................................................................Kappamycetaceae: Kappamyces
AA. Kinetosome and non-flagellated centriole each without a densely granular core.....B
B. Microbody-lipid globule cisterna absent ............................................................ ...............................................family incertae sedis. Batrachochytrium dendrobatidis
(zoospore image from Longcore et al. 1999. Mycologia 91:226)
BB. Microbody-lipid globule cisterna present...........................................................C
C. Fibrillar bridge between kinetosome and non-flagellated centriole diagonal between the two structures.....................................................Alphamycetaceae: Alphamyces
CC. Fibrillar bridge between kinetosome and non-flagellated centriole parallel to and centrally located between the two structures.........................................................D
D. Zone of convergence in fibrillar bridge connecting kinetosome to non-flagellated centriole wide (approximately 0.075 micrometers)...................................................E
DD. Zone of convergence in fibrillar bridge connecting kinetosome to non-flagellated centriole narrow (approximately 0.010 to 0.025 micrometers) ...................................J
E. Kinetosome-associated structure (KAS) as a spur present................................. .............................................................................Rhizophydiaceae: Rhizophydium
EE. Kinetosome-associated structure (KAS) as a spur absent....................................F
F. Kinetosome-associated structure as a shield present...........................................G
FF. Kinetosome-associated structure as a shield absent..........................................H
G. Zoospore contains a single microtubular root..................................................... ......................................................family incertae sedis: Coralloidiomyces digitatus
GG. Zoospore contains multiple microtubular roots................................................. ..............................................................family incertae sedis: Rhizophylctis harderi
H. Mitochondrion lays above and anterior to the kinetosome................................. ................................................................................Aquamycetaceae: Aquamyces
HH. Mitochondrion does not lie above, nor is anterior to, the kinetosome....................I
I. Fenestrated MLC cisterna conspicuous, microbody lobed....................................... ..............................................................................Globomycetaceae: Globomyces
II. Fenestrated MLC cisterna inconspicuous, microbody simple.................................. ..............................................................................Globomycetaceae: Urceomyces
J.MLC cisterna appressed to the lipid globule is simple............................................K
JJ. MLC cisterna appressed to the lipid globule is fenestrated...................................L
K. Microbody lobed, with a portion anterior to the kinetosome................................. ...........................................................................Angulomycetaceae: Angulomyces
KK. Microbody simple, not anterior to the kinetosome......Terramycetaceae: Terramyces
L. Mitochondrion lies above and anterior to the kinetosome.....................................M
LL. Mitochondrion does not lie above, nor is it anterior to, the kinetosome.................P
M. Endoplasmic reticulum ramifies through ribosomal core........................................N
MM. Endoplasmic reticulum not ramifying through ribosomal core..............................O
N. Microtubular root composed of 4 microtubules.................................................. ...........................................................family incertae sedis:Rhizophydium littoreum
NN. Microtubular root composed of 7 microtubules................................................ .............................................................family incertae sedis:Rhizophdium aestuarii
O. Moderately electron dense vesicles proximal to kinetosome................................. ............................................................................Pateramycetaceae, Pateramyces
OO. No moderately electron dense vesicles proximal to kinetosome......................... .......................................................................Gorgonomycetaceae, Gorgonomyces
P. Kinetosome-associated structure (KAS) as a spur present................................... ............................................................................Terramycetaceae: Boothiomyces
PP. Kinetosome-associated structure (KAS) absent................................................ .......................................................................Protrudomycetaceae: Protrudomyces