Ventricleftida

Ventricleftida
Ventrifissura sp. from Powell River, British Columbia, Canada.
Scientific classification Edit this classification
Domain: Eukaryota
Supergroup: Rhizaria
Phylum: Cercozoa
Subphylum: Filosa
Class: Thecofilosea
Order: Ventricleftida
Cavalier-Smith in Howe et al. 2011
Families

And see text

Diversity
6 species

Ventricleftids are a group of thecate zooflagellates that are members of the cercozoan order Ventricleftida. They have dorsoventrally and strongly flattened oval cells. They are known for having a ventral cleft. Filose pseudopods emerge from the ventral cleft. Their flagella emerge subapically. They live in marine environments and both found in Canada and Japan. The order belongs to class Thecofilosea and contains six species across two families and two genera. The two genera in this group, Ventrifissura and Verrucomonas were previously considered tectofilosids. The order's name comes from "venter" meaning belly and "cleft", because of the ventral cleft.

Characteristics

Ventricleftids are a group of dorsoventrally and strongly flattened oval zooflagellates. Scales are nonexistent, extrusomes and rigid theca are present. Two unequal flagella emerge subapically, often from apical notch. Posterior flagellum helps gliding on surfaces. Branched filose pseudopods for feeding emerge from ventral cleft that are separate from and behind the flagellar groove, unlike thaumatomonads and Auranticordis. Verrucomonas has colored warts ranging from yellowish to red, brownish, and golden on the cell surface.

Taxonomy

The order Ventricleftida belongs to class Thecofilosea and phylum Cercozoa and contains six species across two families and two genera:

Ecology and distribution

Ventricleftids are marine organisms. They can be found in coastal environments such as sand habitats. They were reported in both Canada and Japan.

History

The genera Ventrifissura and Verrucomonas were described in 2010, each containing two species. All species were collected from Vancouver, British Columbia, Canada. On the basis of a SSU rDNA tree, they were added to the order Tectofilosida, because in that tree they branched near some uncultured tectofilosids. In 2011, based on SSU rDNA trees, these two genera were transferred to a new order called Ventricleftida in class Thecofilosea. Ventricleftida was recovered as the most basal thecofilosean group. Its name comes from "venter" meaning belly and "cleft", because of the ventral cleft. In 2018, two families were created for two genera, Ventrifissuridae for Ventrifissura and Verrucomonadidae for Verrucomonas. In 2020, two new species of Ventrifissura from Tokyo Bay, Japan and Oarai Sun Beach, Ibaraki, Japan were described. In 2026, it was also reported that a Ventrifissura species was in Powell River, British Columbia, Canada and a Verrucomonas species was in Quadra Island, British Columbia, Canada.

Phylogeny

A phylogenomic analysis in 2026 recovered Ventricleftida as the most basal group within Thecofilosea. Chlamydophryidae is represented by Katarium.

Thecofilosea

References

  1. 1 2 3 4 5 Chantangsi, Chitchai; Leander, Brian S. (2010). "An SSU rDNA barcoding approach to the diversity of marine interstitial cercozoans, including descriptions of four novel genera and nine novel species". International Journal of Systematic and Evolutionary Microbiology. 60 (8). Microbiology Society: 1962–1977. doi:10.1099/ijs.0.013888-0. ISSN 1466-5034.
  2. 1 2 3 4 Shiratori, Takashi; Yabuki, Akinori; Ishida, Ken-ichiro (2020-04-25). "Morphology, Ultrastructure, and Phylogeny of Two Novel Species of Ventrifissura (V. oblonga n. sp. and V. velata n. sp., Thecofilosea, Cercozoa)". Protist. 171 (3) 125731. doi:10.1016/j.protis.2020.125731. ISSN 1434-4610.
  3. 1 2 3 Howe, Alexis T.; Bass, David; Scoble, Josephine M.; Lewis, Rhodri; Vickerman, Keith; Arndt, Hartmut; Cavalier-Smith, Thomas (2011-02-04). "Novel Cultured Protists Identify Deep-branching Environmental DNA Clades of Cercozoa: New Genera Tremula, Micrometopion, Minimassisteria, Nudifila, Peregrinia". Protist. 162 (2): 332–372. doi:10.1016/j.protis.2010.10.002. ISSN 1434-4610.
  4. 1 2 3 Cavalier-Smith, Thomas; Chao, Ema E.; Lewis, Rhodri (2018-04-17). "Multigene phylogeny and cell evolution of chromist infrakingdom Rhizaria: contrasting cell organisation of sister phyla Cercozoa and Retaria". Protoplasma. 255 (5): 1517–1574. doi:10.1007/s00709-018-1241-1. ISSN 1615-6102. PMC 6133090. PMID 29666938.
  5. 1 2 Lax, Gordon; Cooney, Elizabeth C.; Zlatogursky, Vasily; Mtawali, Mahara; Okamoto, Noriko; Jacko-Reynolds, Victoria K. L.; Bjornson, Saelin; Holt, Corey; Hurdeal, Vedprakash G.; Giannotti, Daniele; Keeling, Patrick J. (2026-01-30). "Phylogenomic tree of Cercozoa based on single-cell transcriptomes from 100 uncultured cells". BMC Biology. 24 (1): 55. doi:10.1186/s12915-026-02536-4. ISSN 1741-7007. PMC 12930898. PMID 41618358.
  6. ↑ Solbach, Marcel Dominik; Bonkowski, Michael; Dumack, Kenneth (2024-11-29). "Katarium polorum n. sp., n. g., a novel thecofilosean amoeba (Cercozoa, Rhizaria) from the polar oceans". Journal of Eukaryotic Microbiology. 72 (2) e13071. doi:10.1111/jeu.13071. ISSN 1550-7408. PMC 11822875. PMID 39613721.