Pygmy Marmoset



Domain: Eukarya

            Kingdom: Animalia

                        Phylum: Chordata

                                    Class: Mammalia

                                                Order: Primates

                                                            Family: Callitrichidae

                                                                        Genus: Cebuella/ Callithrix

                                                                                    Species: Pygmaea


            Callithrix pygmaea, also known as the pygmy marmoset in English, has been classified according to the figure above, (Redlist, 2008).



            Pygmy marmoset has been classified in the domain group Eukarya because of the monkey’s cells. The pygmy marmoset like most animals is composed of eukaryotic cells. These cells are different from prokaryotic cells in that they are larger, contain a nucleus, and have organelles through endosymbiosis and evolution, (Kandler, 2002).


            The kingdom Animalia is made up of organisms that are multicellular and heterotrophic (rely on energy from other organisms). These organisms are unlike the kingdom plantae in that they lack the strong cells walls and autotrophic mechanisms (ability to make their own food). Most organisms within the kingdom Animalia can also be classified by the presence of true tissues except for sponges, (ADW: Animalia, 2001) .


            Pygmy Marmosets fall into the phylum Chordata. Some features that define Chordata include pharyngeal slits, dorsal nerve cord, notochord, and post-anal tail. Keep in mind that these features must be present at some point in the organism’s life in order to be classified in the phylum Chordata. Other important features include, bilateral symmetry, three germ layers, a complete digestive system, and a closed circulatory system, (ADW: Chordata, 2001).


            The familiar class Mammalia also includes the pygmy marmoset and is defined by the presence of mammary glands, a vertebral column, and hair at some point in their life. Organisms in Mammalia are generally warm-blooded (endothermic) yet rely on other environmental sources of heat to keep warm, (EOL Mammalia, 2013).


            The category primate is defined by certain physical characteristics that set it apart from other groups of mammals. Familar animals in this category include the ring tailed lemur, gorilla, chimpanzee and, the orangutan. First looking at the brain of a primate it is much larger than other mammals and has a unique groove that separates the first and second visual regions on the left and right side of the brain. Looking down at primate’s extremities we can see that primate have flat nails instead of the usual claws or hooves. In addition, another defining feature is the presence of opposable thumbs in some primates, (Groves and Napier, 2013).



            The family of Callitrichinae is made up of the primates’ marmosets and tamarins. These two groups of primates are the smallest primates in the world making it a perfect family for the pygmy marmoset! Those in the family Callitrichinae lack the opposable thumbs that most primates have and have sharp claws instead of flat nails that they use to dig into trees. Another defining feature of the Callitrichinae is in how they reproduce and parent. Tamarins and marmosets depend on the male for early infant care by carrying the young on their back and only handing the infant over to the mother for feeding, (ADW: Callitrichinae, 2013)For more information on reproductive strategies on the pygmy marmoset visit the reproduction page!


Cebuella/ Callithrix:

 The pygmy marmoset has been put into the category Cebuella and Callithrix because it is still uncertain as to which genus it belongs in. Therefore, the name Cebuella Pgymaea and Callithrix Pygmaea are both referring to the pygmy marmoset. However, new evidence has suggested that because of a determining gene sequence that the pygmy marmoset should be placed in the genus Callithrix, (C. M. L. Barroso et al. 1997). Therefore, the characteristics that define Callithrix are gum feeding and insect feeding organisms that are considered “true marmosets”, (A. Rylands et al., 1993).


            Pygmaea is the species name for the pygmy marmoset and is completely unique to this animal. More information on the species can be found in adaptation, habitat, reproduction, interactions, and quick facts.


Relatedness and Phylogenies 


Figure 1. Hypothesized relationships of the callitrichids based on vocal characters of long calls (Rylands, 1993).

This tree is based on the vocalizations, a morphological characteristic, of the family Callitrichidae. It shows that the Pygmy marmoset’s closest relative is the Marmosets. The Oedipus, Nigricollis, and Mystax groups are more closely related to each other than they are to any other groups.


Figure 2. “Maximum likelihood reconstruction based on the concatenated intron sequences” and “branch lengths represent nucleotide substitutions per site” (Singer et al., 2003).

This tree is based on molecular data from gene sequences, specifically intron sequences. Subunits of DNA called nucleotides were matched from intron sequences, the portion that is removed during RNA splicing. 

Pygmy marmosets belong to either the genus Callithrix or Cebuella (it is still being debated). This tree shows that Callithrix and Cebuella genera are more closely related than to any other genus.

Spider monkeys belong to the genus Ateles and are distantly related to pygmy marmosets; the genus Cebus includes capuchin monkeys (Rylands, 1993).

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