The coatimundi (Nasua) enters the LRT basal to almost all placentals

Traditionally
the coatimundi (Nasua nasua (Figs. 1, 3, 4; originally Viverra nasua Linneaus 1766) is considered a close relative of the raccoon (Procyon), a member of the Carnivora. So it has not gotten the spotlight it deserves.

Figure 1. The coatimundi (Nasua) compared to the ring-tailed lemur (Lemur).

Figure 1. The coatimundi (Nasua) compared to the ring-tailed lemur (Lemur).

By contrast, 
here in the large reptile tree (LRT, 1804+ taxa, Fig. x) Nasua nests outside the Carnivora, alongside Protictis, a Middle Paleocene taxon, and former enigma.

This nesting in the LRT
means the resemblance between coatimumndis and primitive carnivores, like Procyon, primitive primates, like Lemur (Fig. 1), and primitive tree shrews like Tupaia and Ptilocercus, is not mere convergence, but homology.

Overlooked until now,
coatimundis are basal to virtually all placental mammals, including primates and humans. That’s why they look like lemurs. That’s why they look like big tree shrews. That’s why they look like the LRT ancestor of bats, Chriacus, already with those large claws and feet able to rotate 180º enabling head-down descent from trees.

And that’s not all.
Coatimundis also dig with those big claws. So it is no coincidence that Talpa, the mole, is only a few nodes deep in the base of the Carnivora.

It is also worthwhile to compare
Nasua to an outgroup taxon, Caluromys (Fig. 4), an arboreal marsupial close to the base of the Placentalia.

Figure x. Subset of the LRT focusing on Carnivora and basal Placentalia after the addition of Nasua.

Figure x. Subset of the LRT focusing on Carnivora and basal Placentalia after the addition of Nasua. This phenomic cladogram is very different from genomic cladograms you may have seen, some that employ tapirs for outgroups.

Distinct from all members of the Carnivora
in the LRT, Nasua retains three large molars and a vestigial fourth along with a long list of other more subtle traits. Members of the Carnivora have only two molars typically with a large carnassial tooth preceding the upper molars.

Figure 2. Skull of Nasua compared to mid-Paleocene Protictis. The two are a close match and nest together in the LRT.

Figure 2. Skull of Nasua compared to mid-Paleocene Protictis. The two are a close match and nest together in the LRT. Shown about three-fifths life size.

According to Wikipedia
“Adult coatis measure 33 to 69 cm (13 to 27 in) from head to the base of the tail, which can be as long as their bodies. Males can become almost twice as large as females and have large, sharp canine teeth.Coatis have non retractable claws for climbing and digging. They prefer to sleep or rest in elevated places and niches, like the rainforest canopy, in crudely built sleeping nests. Coatis are active day and night but are not nocturnal animals. In the wild, coatis live for about seven years, while in captivity they can live for up to 15 or 16 years. Coatis communicate their intentions or moods with chirping, snorting, or grunting sounds. The pregnant females separate from the group, build a nest on a tree or in a rocky niche and, after a gestation period of about 11 weeks, give birth to litters of three to seven kits. About six weeks after birth, the females and their young will rejoin the band. Females become sexually mature at two years of age, while males will acquire sexual maturity at three years of age.”

The tail is not prehensile, but is used for balance.
Coatis able to rotate their ankles beyond 180°; they are therefore able to descend trees head first.

Figure 3. Skeleton of the coatimundi (Nasua) along with images of the hands, feet, antebrachium and humerus.

Figure 3. Skeleton of the coatimundi (Nasua) along with images of the hands, feet, antebrachium and humerus.

Although Middle Paleocene Protictis
(Fig. 2). nests alongside Nasua, they both had their origin deep in the Jurassic based on Jurassic remains of more derived taxa among the multituberculates. So the coatimundi was a friend, a meal, or at least an observer, of dinosaurs. This genus is a previously overlooked living relative of human ancestors, much more than the agricultural pest some people think.

Figure 1. Mammals at the base of the Placentalia include the outgroup taxon: Caluromys, a basal placental: Genetta, a basal Carnivora: Eupleres, a basal Volitantia: Ptilocercus, a basal Primates: Microcebus, and basal Glires: Tupaia.

Figure 4. Mammals at the base of the Placentalia include the outgroup taxon: Caluromys, a basal placental: Genetta, a basal Carnivora: Eupleres, a basal Volitantia: Ptilocercus, a basal Primates: Microcebus, and basal Glires: Tupaia.

This appears to be a novel hypothesis of interrelationships.
If not, please provide a citation and I will promote it here.


References
Linneaus C 1766. Systema naturae : per regna tria natura, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. 1 (12 ed.). Holmiae: L. Salvii.
wiki/Coati
wiki/South_American_coati

 

 

 

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