Lobosa

Lobosa is a taxonomic group of amoebae in the phylum Amoebozoa. Most lobosans possess broad, bluntly rounded pseudopods, although one genus in the group, the recently discovered Sapocribrum, has slender and threadlike (filose) pseudopodia.^[1] In current classification schemes, Lobosa is a subphylum, composed mainly of amoebae that have lobose pseudopods but lack cilia or flagella.^[2][3]

Lobosa
Amoeba proteus (Tubulinea)
Scientific classification (disputed)
Domain:	Eukaryota
Phylum:	Amoebozoa
Subphylum:	Lobosa Carpenter, 1861, em. Cavalier-Smith, 2009
Groups included
Discosea Tubulinea Cutosea
Cladistically included but traditionally excluded taxa
Conosa

Characteristics

The group was originally proposed in 1861 by William B. Carpenter, who created it as a taxonomic order containing the single family Amoebina.^[4] Carpenter's Lobosa consisted of amoeboid organisms whose endoplasm (endosarc) flows into lobe-like "pseudopodian prolongations." This type of pseudopod, which was understood to be typical of the genus Amoeba "and its allies," differed from the filose (thread-like) or reticulose (netlike) pseudopods of the Foraminifera. The name Lobosa was chosen for these amoebae "as expressing the lobe-like character of their pseudopodial extensions".^[5]

As currently defined, the subphylum Lobosa includes both shelled (testate) and naked amoebae (gymnamoebae), but excludes some organisms traditionally regarded as "lobosean", such as Pelomyxa and Entamoeba (Amoebozoa) and some Heterolobosea (Excavata).

Phylogeny

The subphylum Lobosa is paraphyletic, consisting of a grade of three clades: Discosea, Tubulinea and Cutosea. The first two are part of a paraphyletic superclass Glycopoda, while the latter constitutes the monophyletic superclass Cutosa. The clade uniting Tubulinea + Cutosea + Conosa is named Tevosa, while the clade uniting Cutosa + Conosa is named Evosea.^[6]

Amoebozoa	Discosea Flabellinia Centramoebia Lobosa Tevosa Tubulinea Corycidia Echinamoebia Elardia Evosea Cutosea Conosa Archamoebea Semiconosia Variosea Mycetozoa Dictyostelea Ceratiomyxea Myxogastrea
	Opisthokonta

Gallery

• 
  Chaos carolinensis (Tubulinea)
• 
  Arcella sp. test (Tubulinea)
• 
  Acanthamoeba sp. (Discosea)
• 
  Thecamoeba sp. (Discosea)

References

1. Cavalier-Smith, Thomas; Chao, Ema E.; Lewis, Rhodri (2016). "187-gene phylogeny of protozoan phylum Amoebozoa reveals a new class (Cutosea) of deep-branching, ultrastructurally unique, enveloped marine Lobosa and clarifies amoeba evolution". Molecular Phylogenetics and Evolution. 99: 275–296. doi:10.1016/j.ympev.2016.03.023. PMID 27001604.
2. Smirnov, Alexey V. (2011). "A Revised Classification of Naked Lobose Amoebae (Amoebozoa: Lobosa)" (PDF). Protist. 162 (4): 545–570. doi:10.1016/j.protis.2011.04.004. PMID 21798804. Archived from the original (PDF) on 2016-03-04.
3. Cavalier-Smith, Thomas (2009-02-01). "Megaphylogeny, cell body plans, adaptive zones: causes and timing of eukaryote basal radiations". The Journal of Eukaryotic Microbiology. 56 (1): 26–33. doi:10.1111/j.1550-7408.2008.00373.x. ISSN 1550-7408. PMID 19340985.
4. Carpenter, William Benjamin (1861). "On the systematic arrangement of the Rhizopoda". Natural History Review (Dublin and London). 1 (4).
5. Carpenter, William Benjamin (1862). Introduction to the Study of the Foraminifera. Ray Society. pp. 16–28.
6. Kang, Seungho; Tice, Alexander K; Spiegel, Frederick W; Silberman, Jeffrey D; Pánek, Tomáš; Čepička, Ivan; Kostka, Martin; Kosakyan, Anush; Alcântara, Daniel M C; Roger, Andrew J; Shadwick, Lora L; Smirnov, Alexey; Kudryavtsev, Alexander; Lahr, Daniel J G; Brown, Matthew W (September 2017). "Between a Pod and a Hard Test: The Deep Evolution of Amoebae". Molecular Biology and Evolution. 34 (9): 2258–2270. doi:10.1093/molbev/msx162. PMC 5850466. PMID 28505375.

External links