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Last updated: October 30, 2004.
Nasua narica yucatanica

Order: Carnivora
Family: Procyonidae

General Zoological Data

"There is only one species of coati, Nasua nasua…" (Simpson, 1980). Nowak (1999), however, accepted two species of coatis, the more northern species Nasua narica and the more southern South American species, Nasua nasua. Several subspecies have been alluded to as well, as far instance the species considered here that comes from Mexico. More southern South American coatis are a darker red than the browner northern animals. All have white noses, a feature often referred to. As the name suggests, the animal is characterized by its long, flexible nose and has a long, striped tail held upright most of the time. Coatis extend from Arizona (where they have become uncommon now) to Argentina and prefer wooded areas. They frequent trees, are mostly frugivorous but also hunt small insects, pray on eggs and some rodents. Beisiegel (2001) described the structure and behavior of coatis in Southern Brazil and related their preference for bromeliads. Adult coatis weigh up to 6 kg, while newborns are 100 g or more. Jones (1982) described their longevity as being at least 17 + years. The name "coatimundi" derives from the Tupi Indian name of this species (Gotch, 1979). Many zoos exhibit and breed coatimundis. Timock & Vaughan (2002) made a census of Cebus, coati and armadillo in the Punta Leona Refuge of Costa Rica and suggested from the data the population density. They sighted 148 cebus monkeys, 46 coatis and 8 nine-banded armadillos among some minor numbers of other species. Gompper et al. (1998) used multilocus DNA fingerprints to study the philopatry of coatis; females are more philopatric than males and close relationships exist in specific bands of animals. In a detailed study of mtDNA by Zhang & Ryder (1993) it was found that the lesser panda has no close relationship to either bears or procyonids; also, that the procyonids diverged from one another early although grouping together amongst the carnivores.
Yucatan white-nosed coatimundi at San Diego Zoo.
  2) General Gestational Data

The length of gestation is 10-11 weeks (67-73 days) (Nowak, 1999) and produces between 2 and 7 young that weigh between 100 and 180 g. The placenta of the coatimundi is very similar to that of the raccoon that was well described by Watson (1881 ) and by Vacek (1951), but that publication was not accessible to me. It is zonary and, when delivered, it has an ovoid shape. In 1986 I had access to one full term coatimundi placenta that was still attached to a male neonate weighing 98 g. Its CR length was 12 cm and the tail measured 10.5 cm. This male neonate died from cryptosporidiosis. The placenta was ovoid and measured 5 x 2 cm. At one pole the placenta had a distinct yellow discoloration that is seen histologically as being represented by yellow crystalline deposits and appears to be the remains of the so-called haemophagous organ.

3) Implantation

No early stages of coati placentation have been observed. Moreover, no really early raccoon placentas have as yet been described. These are important aspects to be studied in the future. Mossman (1987) summarizes the procyonid implantation to be "central", the yolk sac orientation to be mesometrial, nidation to be superficial, and amniogenesis as occurring by folding.

4) General Characterization of the Placenta

The placenta of coatimundis has not been described previously. But several studies of the related Raccoon (Procyon lotor) have been made, with a most detailed first description by Watson (1881); several authors have added to our knowledge since. The placenta of the coati is similar in most respects to that of the raccoon. The implanted singleton raccoon fetus (covered by a delicate "epitrichium") described by Watson had a CR length of 4½ inches. It had the head facing the lateral aspect of the uterus, towards the tubal end; the tail was situated between the legs. The (detached) placenta was completely zonary ("annular") and measured 1 ¼ inches in width. A very narrow zone of membranes was described as being present in the circle and there was a smooth border at the edge of the placenta due to attached decidua capsularis. Biggers & Creeds (1962), however, found no interruption of the zonary nature of the raccoon placenta in all their large number of fetuses studied. They were critical of Watson (1881) as having misinterpreted the remains of the "haemophagous organ" as an interruption of the placental "annulus" (Creed & Biggers, 1963). It is noteworthy, however, that their figure clearly shows that the haemophagous zone interrupts the labyrinthine annulus, to obtain its maternal blood from the basal (anti-mesometrial) endometrium. The epitrichium has been described in camels and sloths (see those chapters) and perhaps in the lesser panda. But there is, however, disagreement of the nature of this "membrane" (see Biggers & Creed, 1962, and Creed & Biggers, 1963). These authors believed that Watson (1881) mistook the amnionic membrane as epitrichium and felt that the latter is not a true structure. Watson described the umbilical cord as "hardly existing", as its two arteries and one vein immediately diverged over the placenta. He also noted the absence of the green border zone found in other carnivora placentas. On the other hand, Biggers & Creed (1962) specifically described the "haemophagous organ" as a separate and different type of placentation in the raccoon. They reported it to be present in young gestations and as nearly completely disappearing (remains are a plaque) toward term. As to the papillary structure described of the disk in the fixed specimen, Watson highlighted the enormous ("colossal") nature of the fetal capillaries.

Biggers & Creed (1962) depicted in a preliminary report the identification of the haemophagous organ in the raccoon placenta and defended this term against the connotation of "hematoma", the latter being pathological as they suggested. It is a sac-like structure that emanates from the center of the placenta and "hangs into the allantoic cavity" antimesometrially. Importantly, it is not like the marginal hematomas seen in dogs. This haemophagous organ, as they named it, results from the infiltration/erosion of maternal vessels by cytotrophoblast that there exists in many lamellae and is tall, cylindrical and leads to maternal hemorrhages. The trophoblast is described as containing colored crystals that they interpreted as being hemoglobin breakdown products. While this structure is considered to be a type of hemochorial placentation and is quite large early in gestation, it atrophies later and becomes a small plaque. The same structure is found in several other carnivora, mostly mustelidae as described by Biggers & Creed (1964). While these authors ascribed a resorptive function to this "Blutbeutel", they never stained it for iron, although hemoglobin breakdown is mentioned, as is red cell phagocytosis. As will be seen below, iron stains are negative, as is the case for other carnivores and ungulates that have subchorionic pigment deposits.

Creed & Biggers (1963) described the labyrinth as a trophoblast-covered lamellar structure that surround (enclose) maternal capillaries. The maternal "capillaries" are really sinusoidal in nature and whose endothelium is cuboidal. Then follows a thick PAS+ basal membrane. The trophoblast is syncytial with irregularly disposed nuclei. While this type of placental membrane can initially be described as being vaso-chorial, there is progressive thinning so that ultimately, a hemo-endothelial separation evolves.

The Coatimundi also has a zonary placenta with central attachment of the short umbilical cord. The microscopic structure of the exchange organ is labyrinthine. The interface is primarily endothelio-chorial. Mossman (1987) also makes reference to large central hematomas. While the placenta I observed is bets described as having been "oval", it had originally doubtless been zonary and the yellow discoloration seen at one end is very much most likely the remains of the former haemophagous organ. It conforms in all respects to that described for the remnants of the haemophagous organ of the raccoon. Moreover, the histologic appearance is identical. Regrettably, it was detached from the uterus and the endometrium could thus not be observed.

Cross section through this zonary placenta with fetal surface blood vessels above.
Another section with paler but histologically similar region below.
  5) Details of fetal/maternal barrier

The feto-maternal barrier of Nasua is essentially the same as that of Procyon. In early gestation it would appear that the region of the haemophagous organ has a hemochorial relationship. The labyrinth is identical to that of the raccoon. There is a relatively small amount of villous connective tissue that is covered by trophoblast which, in many areas has a syncytial quality. Other regions are more cuboidal, and projections of fetal capillaries into the trophoblast are focally evident. The presenting maternal surface is largely the cuboidal, and prominent, endothelium of its vascular channels. I have not seen a closer contact between mother and fetus in the sections I possess. Beneath the chorion, the trophoblast is much more cylindrical as will be seen in the photographs below. In the central areas (towards the maternal surface) foci of concentrations of syncytiotrophoblast are present without a clear relationship to exchange function.
Fetal surface of the coati placenta with amnion above and labyrinth below.
The trophoblast beneath the chorionic plate is mostly cylindrical.
Another view of the fetal surface and labyrinth.
Labyrinth of coati placenta.
The feto-maternal barrier of coatimundi.
One focus of a collection of syncytiotrophoblast amidst the labyrinth.
A fetal villous structure with fetal vessels above is covered with trophoblast and abuts the rest of the labyrinth.
  6) Umbilical cord

The umbilical cord of this specimen was 7 cm long, much longer than the length given by Starck (1957) which was given as 0.5 cm. It had no spirals and possessed three blood vessels. The surface was smooth and had no areas of squamous metaplasia. Watson (1881) described a very much shorter umbilical cord to exist in the raccoon gestation but no other information is available at this time. There have been no considerations of the length or type of cords in the many placental specimens described by Biggers and Creed.

7) Uteroplacental circulation

Mossman (1987) described the uterus of raccoons (close relatives) as being bicornuate with a small body, and Watson (1881) provided the only detailed description of a pregnant uterus and its nonpregnant horn. He found a septum between the two horns and stated that the uterine mucosa imperceptibly changes to become vaginal tissues. He also described the uterine vasculature.

8) Extraplacental membranes

A large allantoic sac surrounds the amnionic sac. Into this allantoic sac expands the "haemophagous organ" described earlier that largely disappears toward term in the raccoon. I assume that a similar situation pertains in coatis, although early stages have not been described. There is, however, a remaining yellow portion at the expected site in the placenta I was able to observe and this contains a large number of yellow crystals. The wall is covered with cylindrical epithelial cells (presumably trophoblast) that engage in phagocytosis and contain the same crystals, as will be seen below. Blood was not found in this term placenta of the coati. Despite the fact that this haemophagous organ is speculated to supply iron to the fetus from the maternal hematoma, no iron staining (Prussian blue stains) occurred. No hippomanes are present.

Amnion/allantois membrane. Flat, squamous amnion epithelium below.
The columnar epithelium of the former haemophagous zone with pigment in the trophoblast. No maternal blood.
Higher magnification of previous photograph.
Numerous yellow-orange crystals were present in the membranes at one placental pole, the remains of the hemophagous organ.
Higher magnification of the yellow crystals.
  9) Trophoblast external to barrier

No endometrium was available, but from what is known of raccoon placentation, trophoblast invasion does not occur.

10) Endometrium

The placenta of raccoons and coatis is described as being deciduate, but lacking the uterus of this specimen, the endometrium cannot be described and it has not been reported. There is no decidua found attached to the delivered placenta, only a small amount of fibrin is present. Focal calcifications are present in the connective tissue radiating from the maternal floor into the labyrinth.

This section is from the placental floor and shows a focus of calcification (purple) in decidual remnants.
  11) Various features

No special features are known to me.

12) Endocrinology

Watson (1881) described the ovary of the raccoon as being lobulated and encircled by the Fallopian tube but lacking a bursa. This is contrary to the observation of Mossman & Duke (1973) who described a complete bursa.

13) Genetics

Coatimundis have 38 chromosomes as shown below (from, Hsu & Benirschke, 1970). A variety of other studies cited there have confirmed this karyotype. Wurster-Hill & Gray (1975) have studied other procyonids (all 2n=38) with Giemsa banding and found structural differences among them but they also remarked at the great similarity of some chromosomes to those of felidae. Hybrids have not been described. Zhang & Ryder (1993) examined the mitochondrial DNA sequence evolution of many carnivora and found that lesser pandas were distinct from procyonids and that, as a group, the procyonids separated from each other early in their evolution. Both species (N. narica and N. nasua) have the same chromosomes (see Hsu & Arrighi, 1966; Todd et al., 1966; Panzetta & Alaimo, 1967; Wurster & Benirschke, 1968). A “marker chromosome” with secondary constriction is present in all and is very similar in structure. In general, the karyotype is not very different from that of Felidae; but serologically these families are not closely related as relevant studies showed in the past (Leone & Wiens, 1956; Pauly & Wolfe, 1957).
Karyotypes of Nasua narica.
Karyotypes of Nasua narica.
  14) Immunology

Costa et al. (1995) studied the delayed hypersensitivity reaction to paracoccidioidin in captive arboreal vs. terrestrial animals of Brazil ; they found the former to have a much lower reactivity (22 vs. 83%).

15) Pathological features

Reppas et al. (2001) described two coatimundis with what were interpreted to be bilateral pheochromocytomas. Infectious diseases are important problems for coatis. Thus, Lainson & Shaw (197905) reported fatal pneumocystis infection and, later (1979), they identified organisms similar to Trypanosoma cruzi (the cause of Chagas' disease) in coatis and considered this as a possible health hazard for humans. Trypanosoma evansi, the cause of an important equine disease in Brazil, was isolated from coatis by Quiroz et al. (2000) An experimental study of infecting coatis with this agent led to severe anemia, myocarditis and encephalitis (Herrera et al., 2002). Griner (1983) found tuberculosis (Mycobacterium tuberculosis) in two animals at the San Diego Zoo. This led to the euthanasia of the remainder of animals in the colony which disclosed only dermatitis and mite infection.

Numerous infectious and parasitic afflictions have been described for this species. Thus, Schmidt (1977) identified Onicola luehei in animals from Paraguay; Trypanosoma cruzi-like organisms were identified by Lainson et al. (1979) in Brazilian animals; Trypanosoma evansi was isolated from coatis by Quieroz et al. (2000) and the course of infection followed after experimental transmission (Herrera et al. (2002); Leptospira were isolated from kidneys of Nasua by Lins & Lopes (1984); Toxocara cancrivorus was found by Sprent (1982); Valenzuela et al. (2000) described an epizootic of mange (due to Notoedres cati) in Mexico; Salgado-Maldonado & Cruz-Reyes (2002) found the acantocephalan Porrorchis nickoli also in Mexican animals; fatal infection with Pneumocystis carinii in a freshly-caught coati from the Amazonas; Baird & Neafie (1988) refer to infection with Brugia guyanensis a nematode from South America; over 80% of Brazilian coatis tested positive in an epidemiological study of histoplasmosis, and 65% for antigens of sporotrichosis; Leishmania shawi was found in coatis from Brazil by Lainson et al. (1989) who subsequently studied the possible origin of this infection in patients (Shaw et al., 1991); the animal described here had died from cryptosporidiosis, and Jatobal virus was isolated from a coati in Brazil.

Chittick et al. (2001) described pyometra and an endometrial carcinoma in a coati that had been implanted with melengestrol acetate for 4.5 years.

16) Physiologic data

Boggs & Irvine (1992) studied the respiratory mechanics of coatimundis and found them to be significantly different from the breathing patterns of woodchucks in that the coati had a larger tidal volume. Grant et al. (1976) had earlier made systematic studies of the regulation of pulmonary blood flow. Brimhall et al. (1979) as well as Ahmed et al. (1990) studied hemoglobin composition of coatis, mink and hyenas, while Urashima et al. (1999) examined the milk saccharides of coatis and identified two novel pentasaccharides. McClearn (1985) studied the fiber length of skeletal muscle fibers of distal arm and leg muscles in coatis and compared them with those of the raccoon. The coati is primarily diurnal, while the activity of kinkajou and raccoon occur mainly at night. For that reason, Jacobs & Deegan (1992) studied their retinal pigment and found that the nocturnal species were monochromatic, while the coati was dichromatic.

17) Other resources

Cell strains of a number of Coatimundis can be made available from
CRES at San Diego Zoo by contacting Dr. Oliver Ryder at oryder@ucsd.edu.

18) Other remarks - What additional Information is needed?

There have been no descriptions of early stages of coati placentation; they are badly needed. Likewise, a better description of allantois and length of umbilical cord are needed. There are no endocrine studies, despite the relative wide distribution of the species in the Americas and in zoos.


The animal photograph in this chapter comes from the Zoological Society of San Diego


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