Hematodinium australis

Super Group: 
Alveolata
Phylum: 
Dinophyta
Class: 
Syndinea
Order: 
Syndiniales
Family: 
Syndinidae
Genus: 
Hematodinium
Species: 
australis
Cluster: 
MALV IV
Authority: 
Hudson & Shields 1994

Diagnosis

Diagnosis_Genus: The generic characters of Hematodinium are the amphiesmal structure of the pellicle, the condensed and beaded chromatin that forms V-shaped configurations of the chromosomes, the plasmodial nature of the meront, the continuous state of mitotic activity in the nucleus and the type of mitosis exhibited (dinomitosis) (Chatton & Poisson 1931, Newman & Johnson 1975, Cachon & Cachon 1987).

Diagnosis_Species: Trophont (vegetative stage): Spherical. Amphiesmal alveoli present in the pellicle, no thecal plates or microtubules observed. Cytoplasm with vacuoles empty, or with either membranous debris or lipid-like material. Mitochondria with tubular cristae present. Trichocysts present in trophonts from P. pelagicus (N = 50). Early vegetative stage: 7.9 to 8.9 µm in diameter, average diameter 8.3 µm. Average diameter of nucleus 7.7 µm
(N = 10, EM preparation). Nucleoplasm irregularly dispersed; chromatin uncondensed. Late vegetative stage: 9.9 to 11.9 µm in diameter, average diameter 10.9 µm. Average diameter of nucleus 8.7 µm (N = 10, EM preparation). Nucleoplasm irregularly dispersed; chromatin distinctly condensed in small beads. Double membrane surrounding nucleus. Nucleolus usually present. Vacuoles larger than those present in early trophont. Plasmodium: Ovoid. Similar to late vegetative stage but larger with 2 to 5 nuclei present, 20.1 to 47.5 pm (N = 10, EM preparation). Nucleoplasm irregularly dispersed; chromatin distinctly condensed in small beads. Trichocysts present.

H. australis differs from other forms of Hematodinium primarily by the size of the trophont (vegetative stage), the ovoid plasmodium, and the small beaded form of condensed chromatin in the nucleus. H. australis can be distinguished from H. perezi by its larger vegetative stage, its ovoid as opposed to vermiform plasmodium, its austral geographic location and by its different host species. The trophont of H. australis differs from the Hematodinium sp. clade B from the Tanner crab Chionoecetes bairdi (Meyers et al. 1987) in that it is smaller, possesses trichocysts and has the small form of beaded chromatin. H. australis differs from the Hematodinium sp. Clade B from the Norway lobster Nephrops norvegicus (Fields et al. 1992) in that the trophont stage is larger, it possesses the small form of beaded chromatin and it does not appear to have the vermiform plasmodium that is present in the heart of the lobster.

Etymology

The specific name, australis, is derived from austral and refers to the southern continent, Australia, the region where the parasite was discovered.

Type species

The type species of the genus is H. perezi.

Type illustration / Type locality / Type specimen

Type host: Portunus pelagicus (L.) in hemolymph and hemal spaces of internal organs.
Type locality: Australia, Queensland, Brisbane, Moreton Bay, 153" 06' E, 27" 18' S.
Hapantotype: Material from Portunus pelagicus is from 21 March 1992, with 1 slide and 1 EM block deposited with the Invertebrate Section of the Queensland Museum, Accession Numbers G 211359. Additional material: Australia, Queensland, Brisbane, Moreton Bay, 27" 18' S, 153" 06' E; ex Portunus pelagicus, in hemolymph and hemal spaces of internal organs; Invertebrate Section, Queensland Museum, Accession Number GL 13049 (Shields 1992).

Ecology

Substrate_trophont: endozoic
Substrate_trophont: extracellular
Substrate_spores: planktonic
Sociability_trophont: colonial

Salinity: marine

 

Life cycle

Phases_alternance: haplontic
Symbiont: horizontal
Reproduction_mode: asexual
Generation: <1 month

Observation site(s)

HOSTS

Displaying 1 - 2 of 2
Association with... Region origin Name of site In reference...
Portunus pelagicus Moreton Bay the Bramble Bay subestuary
Scylla serrata Moreton Bay Albert-Logan subestuary