Sand Gazelle (Gazella subgutturosa marica)

Order: Artiodactyla

Family: Bovidae

1) General Zoological Data

"The goitered gazelle, Gazella subgutturosa, inhabits desert and sub-desert steppes of the Arabian peninsula and southwestern Asia to northern China and Mongolia. Four subspecies are recognized by Groves (1985), two of which are presently maintained in captivity in North America. The Arabian sand gazelle, G. s. marica, was once common in the Arabian peninsula, ranging north through eastern Jordan and Iraq, where its range integrated with that of G. s. subgutturosa, commonly known as the Persian or goitered gazelle. Persian gazelles once ranged from eastern Turkey through Iran, Pakistan and Soviet Central Asia. The two forms that are not maintained in North American collections are the Xinjiang goitered gazelle, G. s. yarkandensis, found in the deserts of the Tarim Basin, Xinjiang, China, and the Mongolian goitered gazelle G. s. hilleriana, native to the Gobi and Caidam (Groves, 1985, see Fig. 1). The only captive records of these forms are from European collections. These records indicate that G. s. hilleriana specimens were present in the Opel Zoo as recently as the 1970's, while four G. s. yarkandensis were held by the Berlin Zoo from 1904 to 1906."

This information has been taken from the studbook report's initial statement (Carter & Kingswood, 1991). Relatively small colonies of sand gazelles are now held in a few zoos, both in Europe and in the USA. It has apparently been difficult to differentiate clearly between the different phenotypes by mere inspection of the four subspecies, if this is possible at all. This is also apparent from the next two photographs shown here. Perhaps specific phenotypes have special, as yet unrecognized chromosomal characteristics as well. I am not aware that such comparisons (karyotypes with photographs) have ever been attempted. Rostron (1972) did a careful study of skull measurements of Arabian gazelles and thereby assigned species designation.

The sand gazelle, as well as some related gazelles (e.g. slender-horned) have also been called "rheem" or "rhim", without proper identification of the species. Nevertheless, parasites are named after the "rheem" (e.g. Eimeria rheemi).

Female sand gazelles usually have horns, while typical goitered gazelles rarely do. They are also lighter in coloration and smaller than "Persian gazelles" (G. s. subgutturosa). The animals weigh up to 22 kg; newborns are approximately 2.5 kg.

Distribution of goitered gazelles from Carter & Kingswood, 1991.

Sand gazelle from the San Diego Wild Animal Park.

Note the different phenotype of this sand gazelle from the San Diego Zoo.

Sand gazelle at San Diego Wild Animal Park.

Sand gazelle at San Diego Wild Animal Park.

2) General Gestational Data

Goitered gazelles produce twins in approximately 1/3 of gestations; occasionally triplets are born (Walther, 1968). The gazelles mature in 1 1/2 years and are said to have a gestational length of 5-5.5 months.

3) Implantation

Details of early stages of implantation have not been described.

4) General Characterization of the Placenta

I have had the separate placentas of a set of twin births available for study. Each had 50 cotyledons and weighed 150 and 125 g, respectively. The cotyledons were maximally 4.5 cm in diameter and were 0.4 cm thick. The smallest cotyledons were less than 1 cm in size. Several cotyledons had a "sandy" fetal surface (shown below). The granular deposits were located in the subchorionic spaces and were composed of degenerated cells, debris and fibrin.

Fetal surface of one twin sand gazelle at term. Short, frayed umbilical cord.

Maternal surface of one sand gazelle twin. Note variably-sized cotyledons.

Peculiar surface granularities (faint white arrows) are due to subchorionic degenerative changes.

5) Details of fetal/maternal barrier

Delivered sand gazelle placenta with moderately edematous (autolytic) swelling of villi.

The reddish, subchorionic material is the degenerated debris that is seen on some cotyledonary surfaces.

The same debris under higher magnification.

The ramifications of the villi show a remarkable capillary presence immediately beneath the trophoblast, and some binucleated trophoblastic cells.

6) Umbilical cord

One placenta had a portion of the umbilical cord attached. It was fragmented and measured 5 cm in length and 0.8 cm in width. The cords possessed 4 blood vessels. There were no spirals.

Four blood vessels in the umbilical cord with a central allantoic duct. This one happens to contain blood from delivery. Note the many smaller vessels in the cord.

The allantoic duct carries, artefactually, blood from delivery and is lined by urothelium.

7) Uteroplacental circulation

This has not been studied.

8) Extraplacental membranes

The amnion has a flat, squamous epithelium and applies closely to the allantoic membrane. The latter has columnar epithelium and is vascularized. There is no real decidua developed in the uterus.

Amnionic epithelium on the left and allantoic sac lining on the right with a columnar epithelium and many blood vessels.

Allantoic sac epithelium on the left and trophoblast (between caruncles/cotyledons) on the right.

Allantoic epithelium left and trophoblast (between cotyledons) right.

9) Trophoblast external to barrier

No implanted specimens have been studied and thus it is unknown whether trophoblast invasion occurs. But, in view of the general similarities to other ungulate placentations, this is unlikely.

10) Endometrium

It is unknown whether true decidua develops, but it is unlikely.

11) Various features

No remarkable additional features are worth describing.

12) Endocrinology

Sempere et al. (2001) studied Persian and sand gazelles from a reproductive cycle point of view and determined periods of anestrus and estrus. They measured progesterone and prolactin levels in both species. Melatonin treatment depressed prolactin levels.

13) Genetics

The cytogenetics of goitered gazelles is complex. This is probably due to the fact that the precise place of origin of zoo-held animals is usually unknown and, from reading the literature, it would appear that there are hybrids among what were considered to be subspecies. Some of these animals, those with different chromosome number, should probably be given species designation. Since the animals extend over such a wide region (from Arabia to Mongolia), several "hybrid zones" probably exist and there is intergrading of different types.

Wurster (1972) found 2n=31 in two male, and 2n=30 in one female G. subgutturosa. The uneven number of male/female animals is the result of a translocation of an autosome to the X-chromosome. This is a common feature of many gazelles and antelopes of Africa and seems to have originated before the invasion of Africa by ungulates from Eurasia. It was studied extensively by Effron et al. (1976). This karyotype for G. s. subgutturosa was confirmed by Benirschke & Kumamoto (1987) who found, in numerous sand gazelles (G. s. marica) studied, varied karyotypes. For females there were 2n=32 and 30, and for males 2n=33 and 31. Hybridization between Persian and sand gazelles was assumed to be the reason and it was deemed not to have resulted in subfertility. Similarly, Granjon et al. (1991) assumed hybridization, as they found male sand gazelles from Saudi Arabia with 2n=33 and 2n=31, and females with 2n=32. Nevertheless, our females possessed 2n=31. Kingswood et al. (1994) studied meiosis and karyotypes of Persian gazelles with heterozygosity for the 14/15 autosomal translocation and found that this did not impair fertility. Vassart et al. (1993) found in males from Saudi Arabia and Qatar 33, 32, 31 chromosomes, and in females 32, 31, 30. It involved the same Robertsonian translocations. The problem again being that the precise origin of the population was unknown. Other studies exist as that by Vassart et al. (1995) which also includes protein electrophoretic data. In addition, an important finding of Chinese G. s. subgutturosa by Orlov (1987) identified 2n=30/31; this is essential to know, as no other subspecies exist in that region.

14) Immunology

No studies have been published.

15) Pathological features

Mohammed & Flamand (1996) succeeded in experimental infection of Arabian sand gazelles with Eimeria rheemi. This is a "natural" and frequent infection of the rheem (sand gazelle) and causes diarrhea (Hussein & Mohammed, 1992). Sand gazelles and other local Arabian gazelles are often infected with sarcocystis parasites (Mohammed et al., 2000). Fenwick (1983) described cryptosporidiosis in a neonatal Persian gazelle.

Griner (1983) did not differentiate the various types of gazelles and found that among "Persian gazelles" the primary cause of death was trauma and, in neonates, "malnutrition".

16) Physiologic data

Hematologic data were provided for mountain gazelles (Gazella gazella) by Rietkerk et al. (1994), while Vassart et al. (1994) gave the details for serum chemistry values in sand gazelles. The natural diet was detailed by Mohamed et al. (1991). A very detailed description of the behavior of all kinds of gazelles was published by Walther (1968).

17) Other resources

The research department (CRES) of the Zoological Society of San Diego has had a long interest in the genetics of gazelles, and, especially in the polymorphism of goitered gazelles (Kingswood et al., 1994). As a consequence, numerous cell strains are available of various karyotypes by requesting them from Dr. Oliver Ryder at oryder@ucsd.edu.

There is a very extensive bibliography on all aspects of sand gazelles and the related forms. This has been gathered by the King Khalid Wildlife Research Center, Thumammah and can be made available by the National Commission for Wildlife Conservation and Development, P.O. Box 61681, Riyadh 11575, Kingdom of Saudi Arabia.

18) Other remarks - What additional Information is needed?

Information is needed on reproductive endocrine data and the cytogenetics of the other species of goitered gazelles.

Acknowledgement

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