Chacoan Pygmy Opossum

Taxobox
name = Chacoan Pygmy Opossum
status = VU
status_system = iucn3.1
regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = Didelphimorphia
familia = Didelphidae
subfamilia = Didelphinae
genus = "Chacodelphys"
genus_authority = Voss et al., 2004
species = "C. formosa"
binomial = "Chacodelphys formosa"
binomial_authority = (Shamel, 1930)The Chacoan Pygmy Opossum ("Chacodelphys formosa") is a recently described genus and species of didelphimorph marsupial. The only species in "Chacodelphys", "C. formosa", is known from only one specimen collected in 1920 in the Chaco of Formosa Province, Argentina.

Description

The Chacoan Pygmy Opossum is the smallest known species of didelphid. It has a head-body length of 68 mm, a tail of 55 mm and a hind foot of 11. It differs from the other "marmosine" genera ("Marmosa", "Micoureus", "Monodelphis", "Thylamys", "Tlacuatzin", "Gracilinanus", "Marmosops", "Lestodelphys") in having a long third manual digit, no distinctly tricolored pelage, a long fourth pedal digit, and a tail shorter than head-body. No other marmosine genera has this combination of characters.

Taxonomic history

"C. formosa" was originally described as "Marmosa muscula" Shamel (1930a); however, this name is preoccupied, so Shamel (1930b) renamed it "M. formosa". Afterwards, George Tate (1933) considered it a valid member of his "Elegans" group" (="Thylamys") of "Marmosa", whereafter it has been variously synonymized or treated as a distinct species of "Marmosa" or "Thylamys" until 1989, when Gardner & Creighton (1989) listed it as a synonym of "Gracilinanus agilis", and then later separated from this species as "G. formosus". Finally, Voss et al. (2004) erected the new genus "Chacodelphys" for the species.

References

*Gardner, A.L. & Creighton, G.K. 1989. A new generic name for Tate's microtarsus group of South American mouse opossums (Marsupialia: Didelphidae). Proceedings of the Biological Society of Washington 102:3–7.
*Shamel, H.H. 1930a. A new murine opossum from Argentina. Journal of the Washington Academy of Sciences 20:83-84.
*Shamel, H.H. 1930b. A new name for Marmosa muscula Shamel. Journal of Mammalogy 11:311.
*Tate, G.H.H. 1933. A systematic revision of the marsupial genus Marmosa with a discussion of the adaptive radiation of the murine opossums (Marmosa). Bulletin of the American Museum of Natural History 66:1–250.
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*Voss, R.S., Gardner, A.L. & Jansa, S.A. 2004. On the relationships of "Marmosa" formosa Shamel 1930 (Marsupialia, Didelphidae), a phylogenetic puzzle from the chaco of northern Argentina. American Museum Novitates 3442:1-18, 2 June 2004.