Cryptonanus
| Cryptonanus | |
|---|---|
| |
Cryptonanus agricolai
| |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Infraclass: | Marsupialia |
| Order: | Didelphimorphia |
| Family: | Didelphidae |
| Subfamily: | Didelphinae |
| Tribe: | Thylamyini |
| Genus: | Cryptonanus Voss et al., 2005 |
| Type species | |
Marmosa agilis chacoensis
, 1931 | |
| Species | |
| |
| |
Cryptonanus is a
extinct. Although the first species were discovered in 1931, the genus was not recognized as distinct from Gracilinanus
until 2005. It includes small opossums with generally grayish, sometimes reddish, fur that are mainly distinguished from other opossums by characters of the skull.
Taxonomy
Species of Cryptonanus were first described in 1931 by
C. ignitus, was described as a species of Gracilinanus in 2002. At that time, the species of Cryptonanus were variously regarded as separate species or as synonyms or subspecies of other species of Gracilinanus.[5]
generic name, Cryptonanus is derived from the Ancient Greek words κρυπτος kryptos (hidden) and νανος nanos (dwarf) and was chosen because Cryptonanus species are small and their true identity was long hidden by taxonomic synonymy.[9] Cryptonanus is currently classified in the tribe Thylamyini of subfamily Didelphinae within the opossums.[10]
Voss and colleagues recognized each of the five names they referred to Cryptonanus—agricolai, chacoensis, guahybae, ignitus, and unduaviensis—as separate species, although they could find few distinguishing characters between them.[1] Further research in this matter is needed.[11]
Species
Cladogram of living Cryptonanus species.[12][13]
| |||||||||||||||||||
The five species currently recognized are:
| Image | Scientific name | Distribution |
|---|---|---|
|
Cryptonanus agricolai |
states of Ceará, Goiás, and Minas Gerais in eastern Brazil[4] |
Cryptonanus chacoensis |
southeastern Bolivia, Paraguay, northeastern Argentina, and Uruguay[14] | |
Cryptonanus guahybae |
coastal Rio Grande do Sul, Brazil[15] | |
| † Cryptonanus ignitus |
single locality in | |
Cryptonanus unduaviensis |
northern and eastern Bolivia[17] |
Description
Cryptonanus species are small opossums even within their family and weigh about 15 to 40 grams (0.53 to 1.41 oz). The fur is unpatterned and usually reddish or grayish brown above and is grayish or unpigmented below.
mammae. The tail looks naked to the unaided eye, but each scale in fact harbors three short hairs.[1] Species of Cryptonanus and Gracilinanus are hardly distinguishable on external characters, though Cryptonanus species may have shorter tails, larger ears, broader eye-rings, and longer whiskers. More secure characters separate the skulls of the two genera.[18] In addition to the presence of the additional foramen ovale, which exhibits some variation within species,[19] Cryptonanus usually lacks maxillary fenestrae, perforations of the palate near the first and second molars, has the second upper premolar shorter than the third,[20] lacks a rostral process, which extends the premaxillary bone further to the front,[21] and usually has additional cusps on the upper canine tooth.[22] The species of Cryptonanus differ in coloration, size, and some characters of the teeth.[23]
The karyotype of C. agricolai includes 14 chromosomes with 24 major arms (2n = 14, FN = 24).[24]
References
- ^ a b c d Voss et al., 2005, p. 5
- ^ Tate, 1931, p. 10
- ^ Tate, 1931, p. 11
- ^ a b Gardner, 2009, p. 41
- ^ Gardner, 2009, p. 40
- ^ Voss et al., 2005, p. 2
- ^ Voss et al., 2005, fig. 4
- ^ Voss et al., 2004, p. 6, footnote 4
- ^ Voss et al., 2005, p. 11
- ^ Voss and Jansa, 2009
- ^ Voss and Jansa, 2009, p. 128
- PMID 31800571.
- S2CID 17393886.
- ^ Gardner, 2009, pp. 41–42
- ^ a b Gardner, 2009, p. 42
- ^ Diaz and Barquez, 2008
- ^ Gardner, 2009, p. 43
- ^ Voss et al., 2005, p. 6
- ^ Voss et al., 2005, pp. 6–7
- ^ Voss et al., 2005, p. 7
- ^ Voss et al., 2005, pp. 9–10
- ^ Voss et al., 2005, pp. 10–11
- ^ Gardner, 2009, pp. 40–41
- ^ Voss et al., 2005, p. 14
Literature cited
- Diaz M. and Barquez, R. 2008. Cryptonanus ignitus. In IUCN. IUCN Red List of Threatened Species. Version 2009.2. <www.iucnredlist.org>. Downloaded on March 26, 2010.
- Gardner, A.L. 2009. Mammals of South America. Volume 1: Marsupials, xenarthrans, shrews, and bats. University of Chicago Press, 669 pp. ISBN 978-0-226-28240-4
- Tate, G.H.H. 1931. Brief diagnoses of twenty-six apparently new forms of Marmosa (Marsupialia) from South America. American Museum Novitates 493:1–14.
- Voss, R.S. and Jansa, S.A. 2009. Phylogenetic relationships and classification of didelphid marsupials, an extant radiation of New World metatherian mammals. Bulletin of the American Museum of Natural History 322:1–177.
- Voss, R.S., Lunde, D.P. and Jansa, S.A. 2005. On the contents of Gracilinanus Gardner & Creighton, 1989, with the description of a previously unrecognized clade of small didelphid marsupials. American Museum Novitates 3482:1–34.
- Voss, R.S., Gardner, A.L. and 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.