Japanese Serow (Capricornis crispus)

Order: Artiodactyla

Family: Bovidae

1) General Zoological Data

There are two species of serow, Capriconis sumatrensis and Capriconiscrispus. The latter has two subspecies, the Japanese and Formosan serows.The Japanese serow is a mountainous, endangered species in Japan that isbeing conserved at the Japanese Serow Center on Gozaisho Mountain.

The presumed evolution of the Rupicaprinae has been traced from fossilsand bone structures by Dolan (1963) and it is also graphically depictedbelow. Speciation is presumed to have proceeded via intermediate speciesfrom chamois-like ancestors (Soma & Kada, 1984) to the Rocky MountainGoat as its latest derivative. More recently, the phylogenetic relationshipshave been studied by examination of mtDNA and, especially, nuclear DNA genesof proteins. Thus, Chikuni et al. (1995) undertook a major effort to studynucleotide substitutions of a wide variety of Bovidae for the kappa-caseinand cytochrome b gene sequences and compared their results with findingsfrom other molecular studies. In their view, this essential protein andits genes provided better resolving power than did mtDNA evolution. Theysuggested a cattle/pig split to have occurred 60 MYA, Cattle/sheep &goat 20 MYA, and Sheep/goat 5 MYA. Their results also place the chamoisas being more ancestral, whence derived Japanese serow, and then the othertwo serow species.

Adult serows weigh between 50 and 100 kg and both sexes have short curvedhorns (Nowak, 1999) whose crystalline components were studied in detailby Hashiguchi & Hashimoto (1995). Further general details on Japaneseserows have been provided by Benirschke & Soma (1972 published (in Japanese);and by Benirschke (1973; Soma & Kada).

Japanese Serow at Gozaisho Mountain, Japan.

Japanese Serow with young at San Diego Zoo's Wild Animal Park.

Presumed chromosomal evolution of Rupicaprini.

2) General Gestational Data

According to Nowak (1999), the gestation is 7 months long and usually singletonsare born. The recorded longevity is 18 years 7 months in captivity (Jones,1993). General details on reproduction and neonatal growth were publishedby Sugimura et al. (1981) in a paper that was not accessible.

3) Implantation

No studies of early stages of placentation are known to us.

4) General Characterization of the Placenta

KB had one placenta available for dissection. It came from a neonatal deathoccurring at San Diego Zoo's Wild Animal Park and its gestation was at term.The placenta was slightly autolyzed and weighed 470 g. This placenta had60 cotyledons measuring up to 4 cm in diameter in the main uterine horn,but the cotyledons were as small as 0.5 cm in the secondary horn. Therewas only a 1 cm umbilical cord attached to the membranes. Its surface wascovered by thin amnionic epithelium.

In addition, Hiroaki Soma of Tokyo had available the material from two otheranimals collected at the Serow Center of Gozaisho Mountain, and the YokohamaZoo, Japan. Both of these specimens came from stillbirths at 212 and 213 days gestation. The first placenta was attached to a uterus and had 91 cotyledonswith maximal diameter of 4 cm. Uterus and placenta weighed 675 g, the malefetus was 760 g, and the cord measured 13 cm in length and possessed fourvessels. The other case was a stillbirth with a fetus 41 cm in CH lengthhaving a 15 cm cord (4 vessels) and 72 placental cotyledons measuring upto 6.5 cm in diameter. Pictures of both will be shown next.

Since this original description a placenta from a term, surviving infant at San Diego Zoo's Wild Animal Park became available. It weighed 110 g and had only 14 large (4 cm) flat cotyledons. A 12 cm umbilical cord with four vessels and allantoic duct was present.

Serow fetus in uterus at 212 days gestation. Note pale tip of unoccupied uterine horn at left.

Stillborn fetus with short cord attached to the opened placental sac.

This placenta had 72 cotyledons of slightly concave type.

5) Details of fetal/maternal barrier

This is an epitheliochorial placentation with tall cylindrical trophoblastcovering the villi and interspersed with numerous binucleated trophoblastcells. The villi in the slightly autolyzed placenta from San Diego are muchmore edematous than is probably normal. Moreover, it is not so prominentin the other two placentas shown. In the trophoblast under the chorionicplate one finds relatively small quantities of yellow pigment.

Villi attached to endo/myometrium; arrows point to maternal root of cotyledons.

Villi and purple maternal tissue interdigitating. PAS stain.

Horizontal section through an attached cotyledon.

Higher magnification of cross-sectioned cotyledon.

Cross section, stained with Mallory connective tissue stain.

The villi of this mature placenta are edematous-appearing because of the autolysis.

Binucleated trophoblast at arrow.

Pigmented trophoblastic cells beneath the chorionic plate.

6) Umbilical cord

Clearly, the 1 cm length of umbilical cord that was received in the firstspecimen is an incorrect length, but the real length of the umbilical cordwas unknown until the Japanese specimens became available. The piece receivedinitially was attached to the placenta and had already split into its severallarge surface vessels and the allantoic sac was opened. Thus, the earlyfinding of only three large blood vessels was incorrect. The two Japanesespecimens had four blood vessels (and allantoic duct), were 13 and 15 cm long, and had a left spiral.

The new placenta had a 12 cm cord as well that was similarly structured.

Cross section of umbilical cord of Japanese serow.

7) Uteroplacental circulation

No studies are known to us.

8) Extraplacental membranes

The allantoic sac is large and lined by cylindrical epithelium and has a large number of blood vessels. The thin amnion contains no vessels. No remnants of yolk sac were found.

Intercotyledonary membrane with trophoblast below.

Amnion above, allantois below.

9) Trophoblast external to barrier

There is no trophoblastic infiltration of endometrium or uterus. In view of the general similarity to ungulates with similar placentas, however, such infiltration seemed highly unlikely anyway.

10) Endometrium

Whether there is endometrial decidualization is unknown. Very little typical decidua was present in the term uterus of a dead dam.

11) Various features

A subplacenta is not present.

12) Endocrinology

We know of no endocrine studies in this animal.

13) Genetics

The Japanese serow has 50 chromosomes (Benirschke et al., 1972; Ito et al., 1972; Soma & Kada, 1984). The Sumatran serow has 2=48 (Soma et al., 1987), and the Formosan subspecies of Capricornis crispus (Capricornis crispus swinhoei) is identical to that of the Japanese animal (Soma & Kada, 1984). Presumably, Robertsonian fusion mechanisms were operative in the speciation, as all species have a "NF" of 60.

Karyotype of male Japanese Serow.

14) Immunology

Sugimura et al. (1990) described the composition of lymph nodes in a variety of animals, including the serow, but we are not aware of any other immunological studies, other than surveys. Thus, Inoshima et al. (1999; 2001) surveyed Japanese serows and found a 20% immune response to parapox virus.

15) Pathological features

A macerated fetus was found by Yamamoto et al. (1994) among "2,138 pregnant Japanese serows". The fetus appears to have been retained, as all placentomes had disappeared and there was an inflammatory reaction. Parapoxvirus infection of the interdigital glands was found in a wild serow by Suzuki et al. (1997a). Numerous parasites have been identified in serows, thus: Inoue (1989) found four species of Eimeria that were non-infectious for goats; Gongylonema was identified by Chakraborty (1994); Inoue & Imura (1991) identified Eimeria gozaishoensis in a Formosan serow, and Uni et al. (2001, 2002) isolated several Cercopithifilaria species from Japanese serows. A wild serow with dermatitis was found to suffer from infection by Chorioptes bovis, apparently a new host for this mite (Shibata et al., 2003). Onchocerca was found to cause lesions of the ligaments to the olecranon, with chronic tendonitis (Suzuki et al., 1997b).

16) Physiologic data

The serow in Japan is protected and at the same time it is pursued because of its raiding crops. Therefore, Deguchi et al. (2001) conducted a study to ascertain food preferences. They found that the animals prefer crop rather than wild plants and inferred that this relates to the higher protein content of crops.

A large number of anatomical studies have been performed on this rare animal. Yamamoto et al. (1998) and Kitamura et al. (2003) described the microscopic findings of the forestomach anatomy. Atoji et al. (1996) found significant differences in the structure of the infraorbital glands of Formosan and Japanese serows. The masseter muscle structure was described by Suzuki (1989), and the interdigital gland of a Formosan serow was described by Atoji et al. (1995) and compared with that of a Japanese serow (Atoji et al., 1987). Bronchial tree and lungs were examined by Nakakuki (1986). Atoji et al. (1987a) studied the brachial plexus and later, the lumbosacral plexus of Japanese serows (1987b). The same authors also examined the histology of preputial glands (Atoji et al., 1989). Takahashi et al. (1984) determined the lipid composition of red cell membranes in serows, and Kita et al. (1995) described mammary glands and teats.

17) Other resources

Cell strains of fibroblasts are available from CRES at the San Diego Zoo by contacting Dr. Oliver Ryder at oryder@ucsd.edu.

18) Other remarks - What additional Information is needed?

No early stages of implantation have been described and would be desirable to obtain. Endocrine studies during pregnancy are needed.

Acknowledgement

The first animal photograph in this chapter comes from Mr. Takeuchi at the Japan Serow Center, Gozaisho Mountain, Japan.