Western Tufted Deer (Elaphodus cephalophus cephalophus)

Order: Artiodactyla

Family: Cervidae (Muntiacinae)

1) General Zoological Data

This is the only member of the genus Elaphodus, a species from Southern China and Burma. It closely resembles the muntjacs in many ways according to Nowak (1999) and other authorities. Elaphodus is contained in the subfamily muntiacinae and three subspecies are recognized (Dolan, 1986). It is one of the most primitive antlered deer. In contrast to muntjacs though, this species lacks the prominent frontal bony ridge. Otherwise, these two species are very similar. Only males carry antlers, in both species. They are smaller in tufted deer although the animals are slightly larger than muntjacs. Their canines are also smaller.

Tufted deer are said to have originated in the Miocene (Dolan, 1971); they separated from muntjacs about 3.4 MYA according to the study of mtDNA by Lan & Shi (1993). Both sexes also bark and are still actively hunted despite their dwindling numbers. Their maintenance in captivity has been described by Schwenn (1988). Adults weigh 17-50 kg and have a single young. These animals are rarely seen in zoos, but the San Diego Zoo has had an active reproductive colony since 1985. The placenta shown here was retrieved from a singleton gestation at term. The longevity of tufted deer is over 12 years in captivity (Jones, 1993).

Western Tufted Deer at the San Diego Zoo. Notice the small canine tooth and "tuft" of hair.

2) General Gestational Data

The length of gestation is 210 days and the animals usually produce a single young according to Helin & Houji (1982).

3) Implantation

No early stages of implantation have been described and it is unknown how many caruncles the uterus possesses.

4) General Characterization of the Placenta

This was a cotyledonary placenta that weighed 95 g and, remarkably, it had only two cotyledons, although they were large (9 x 10 x 03 cm and 8 x 11 cm). It is a villous placenta, has an epithelio-chorial relationship to the mother, and possesses a large allantoic sac. Since this original description, another full-term placenta of a surviving neonate became available. It appears to have been more complete, as it weighed 400 g and had 5 large, flat cotyledons measuring up to 11 cm in greatest diameters. Its umbilical cord had four large and numerous smaller blood vessels and a large allantoic duct.

Fetal aspect of the tufted deer placenta with its two cotyledons. Note the relatively long umbilical cord whose allantoic sac's membranes commence near the insertion of the cord between the two cotyledons.

Maternal aspect of the same delivered placenta from a tufted deer.

5) Details of fetal/maternal barrier

The villous structure and general appearance is very much the same as that found in other deer (see chapter on deer). The villi are covered by a single layer of cuboidal epithelium and there are scattered binucleate trophoblastic cells as in other deer. Occasional trophoblastic cells on the villous surface contain a yellow pigment, but the large among of pigment found beneath the chorionic plate in other Artiodactyla is absent. On must assume that the tufted deer have an epithelio-chorial placenta and that the villi were dislodged from the caruncular interstices during detachment of the placenta. No implanted placenta has yet been available.

Low-power view of the placental organization with the chorionic plate and fetal vessels above. There is mild autolysis that makes the villi unduly edematous appearing.

Villous surface with fetal blood vessel in the center and fetal capillaries immediately beneath the cuboidal to cylindrical trophoblast.

6) Umbilical cord

This specimen's umbilical cord measured 20 cm x 2 cm and was not spiraled. It contained four blood vessels. Approximately 5 cm from the insertion site, between the two cotyledons, the membranes of the allantoic sac meet the amnionic sac. A pair of blood vessels supplies each cotyledon. In the center of the cord is a large allantoic duct that is surrounded by capillaries. Other smaller vessels surround the large arteries and some of the smaller vessels have a musculature. The surface has no areas of squamous metaplasia. The epithelium of the allantoic duct is urothelial.

Umbilical cord of second specimen with allantoic duct at 11 o'clock.

Section of umbilical cord showing the allantoic duct, portion of one large vessel and smaller allantoic vessels surrounding the duct.

7) Uteroplacental circulation

This is completely unknown.

8) Extraplacental membranes

The amnion is composed of a thin layer of connective tissue and has a flat squamous epithelium. No squamous metaplasia was present. The allantoic sac was attached to the cord near its insertion on the placenta and has blood vessels. No hippomanes were present.

9) Trophoblast external to barrier

It is unlikely that trophoblast invades to uterus, but no implanted placenta has yet been studied.

10) Endometrium

There is no knowledge on the gestational endometrium. Muntjacs have only one uterine horn. It is unknown what the situation is for the tufted deer. Whether there is decidualization of the endometrium in pregnancy is unknown.

11) Various features

There are no other features of relevance.

12) Endocrinology

No studies have been published and we have not undertaken endocrine analysis of these animals.

13) Genetics

Tufted deer have unusual chromosomes according to the most recent study of these unusual animals. Shi et al. (1991) found that females had 46 or 47 chromosomes, while males had 47 or 48 chromosomes. In meiotic studies an autosome/X translocation was identified. Other studies are cited, such as the one by Zhang et al. (1984) and Wang &. Quan (1981). Hybrids have not been described. Studies of mtDNA by Lan & Shi (1993) indicated that muntjacs and tufted deer are closely related.

14) Immunology

There are no publications on immunological characteristics.

15) Pathological features

At this zoo we have seen occasional stillbirth without abnormalities. No significant pathology has been described.

16) Physiologic data

No studies have been published to my knowledge.

17) Other resources

Several cell lines of these animals are stored in the "Frozen Zoo" at CRES of the San Diego Zoo. They were used in the study by Shi et al. (1991) and can be made available by contacting Dr. Oliver Ryder at oryder@ucsd.edu.

18) Other remarks - What additional Information is needed?

There is no knowledge on implantation, hormones, accurate length of gestation, and other reproductive parameters. Few pathologic findings have been made. Much more knowledge is needed on all these features. An implanted placenta needs to be studied.

Acknowledgement

The animal photograph in this chapter comes from the Zoological Society of San Diego. I appreciate also very much the help of the pathologists at the San Diego Zoo.