1) General zoological data
The name Pedetes derives from the Greek word for dancer or leaper. It is most appropriate for this charming small nocturnal rodent (Gotch, 1979). This is the sole member of the family. It lives in Africa and extends from Kenya to the Cape . Some authors have considered that a second species ( Pedetes surdaster ) exists, while most authorities believe it to be the same animal (see, however, the discussion by Matthee & Robinson, 1997b) . In addition, regional subspecies have been considered (see Otiang'a-Owiti et al., 1992).
|A characteristic springhaas in the San Diego Zoo.|
|A characteristic springhaas in the San Diego Zoo.|
2) General gestational data
Reproduction occurs throughout the year and was studied extensively by Merwe et al. (1980). These authors also studied some endocrine parameters. A single young is born after an estimated 78-82 days of gestation. The exact length of pregnancy, however, had not been determined decisively and was disputed (Merwe et al., 1980). Now it is thought to be 60-77 days (see below). Puschmann (1989) stated that there might be 3-4 pregnancies per year in captive animals. Twins are rare but they have been reported (Nowak, 1999; Rosenthal & Meritt, 1973). Butynski (1979) who made an extensive ecological study estimated that twins occur in less than 1% of pregnancies. One authors' young weighed 300 g, another was 278 g. Butynski (1979) found the average neonatal weight to be 250 g. He received a pregnant female and described the neonate in some detail. The neonate weighed 250 g, the mother weighed 1,785 g and a male weighed 2,665 g. He provided detailed information on the growth of that male young.
The young leave the burrows when they are 1.5 kg in size and spermatogenesis begins at 2.5 kg size and is continuous throughout life. Most males have inguinal testes, rarely were they found to be scrotal; they can then be readily retracted into abdominal pouches (Coe, 1969). The reproductive tracts of both sexes were described in great detail by Coe (1969), and also by Fischer & Mossman (1969). The latter authors stated that the uterus is "duplex" and only occasionally did the cervix assume a "V-shape". In those cases, there is only one os while, normally, there are two cervical ostia. The ovaries are contained in a bursa. There are no cervical glands, but the clitoris has two glands. The cervix is lined by squamous epithelium and the penile glans has spines. Implantation occurred on the side of the corpus luteum, mostly on the left. But, ovulation does occur on both sides and fetuses were five times on the right, and six times on the left side, according to Coe (1969). Likewise, Otiang'a-Owiti et al. (1992) found an equal number of gestations on the right as on the left side of the uterine horns.
It should be stated here that the publication by Coe (1969) is on Pedetes surdaster, the Kenyan "species". Since that publication, however, this species has been joined with P. capensis and probably there is no further use here to separate them. All anatomical aspects appear to be similar, as are weight, breeding, and length of gestation (estimated to be 2 months by Coe, others state 77 days). An earlier publication on reproduction by vs. Horst (1935) was not accessible to me.
General Characterization of the Placenta
Details of fetal/maternal barrier
|At left is the maternal floor with the numerous giant cells and endometrial debris.|
|At left is a large fetal blood vessel (bottom) that distributes fetal blood into the villi.|
|The large maternal vessel at right borders on trophoblast but the endothelium is not visible in this slightly autolyzed specimen.|
6) Umbilical cord
The umbilical cord was not available to me and is not even mentioned in the exhaustive study of Fischer & Mossman (1969). The only probable features are the presence of yolk sac- and allantoic ducts. Otiang'a-Otiwi et al. (1992) found the cord to have three allantoic vessels (2A, 1V), and two yolk sac vessels (1A, 1V). They did not mention ducts and did not measure the lengths.
7) Uteroplacental circulation
The circulation of springhaas placentas was alluded to and diagrammatically shown in Fischer & Mossman's study (1969). A large maternal vessel develops in the preplacenta, divides and send its blood to the placental surface whence it is returned in fine channels. Here it borders trophoblast and allows exchange. These authors considered this to be a typical counter-current setup of the labyrinth. The stem villi of lobules are perfused by a thin-walled fetal arteriole.
|Fetal surface of disc with fetal vessel, small allantoic cavity, and large (central) maternal channel. In a few areas one may see some endothelial cells.|
8) Extraplacental membranes
The "free membranes" are the bilaminar omphalopleure with thick Reichert membrane. The external epithelium is not endodermal, but it is the inner epithelium. Thus, this is not an inverted yolk sac placentation. Instead the ectodermal epithelium fuses with the endometrium and here forms, in essence, a syndesmochorial region. This membrane and the uterine wall are very thin.
Trophoblast external to barrier
Other remarks - What additional Information is needed?
Bogart, M.H., Scollay, P.A., Cooper, R.W. and Benirschke, K.: Springhaas (Pedetes capensis). Chromos. Inform. Serv. 30:14-15, 1976.
Butynski, T.M.: Reproductive ecology of the springhaas Pedetes capensis in Botswana. J. Zool. (London) 189:221-232, 1979.
Coe, M.J.: The anatomy of the reproductive tract and breeding in the spring haas, Pedetes surdaster larvalis Hollister. J. Reprod. Fertil. Suppl. 6, 159-174, 1969.
Deane, H.W., Rubin, B.L., Driks, E.C., Lobel, B.L. and Leipsner, G.: Trophoblast giant cells in placenta of rats and mice and their probable role in steroid hormone production. Endocrinology 70:407-419, 1962.
Fischer, T.V. and Mossman, H.W.: The fetal membranes of Pedetes capensis, and their taxonomic relevance. Amer. J. Anat. 124:89-116, 1969.
Gotch, A.F.: Mammals - Their Latin Names Explained. Blandford Press, Poole, Dorset, 1979.
Hediger, H. Gefangenschaftsgeburt eines afrikanischen Springahasen, Pedetes caffer. Zool. Garten 17:166-169, 1950.
C.J. v.d.: On the reproduction of the springhare, Pedetes caffer.
Pamph. S. Afr. Boil. Soc. 8:47, 1935.
Matthee, C.A. and Robinson, T.J.: Molecular phylogeny of the springhare, Pedetes capensis , based on mitochondrial DNA sequences. Mol. Biol. Evol. 14:20-29, 1997a.
Matthee , C.A. and Robinson, T.J.: Mitochondrial DNA phylogeography and comparative cytogenetics of the springhare, Pedetes capensis (Mammalia: Rodentia). J. Mammalian Evol. 4:53-73, 1997b.
Merwe, M.v.d.. Skinner, J.D. and Millar, R.P.: Annual reproductive pattern in the springhaas, Pedetes capensis. J. Reprod. Fertil. 58:259-266, 1980.
Nowak, R.M.: Walker's Mammals of the World. 6th ed. The Johns Hopkins Press, Baltimore, 1999.
Otiang'a-Owiti, G.E., Oduor-Okelo, D. and Gombe, S.G.: Foetal membranes and placenta of the springhare (Pedetes capensis larvalis Hollister). Afr. J. Ecol. 30:74-86, 1992.
Owiti, G.E.O., Oduor-Okelo, D. and Gombe, S.: Ultrastructure of the chorioallantoic placenta of the springhare Pedetes capensis larvalis Hollister. Afr. J. Ecol. 23:145-152, 1985.
Peinke, D.M. and Brown, C.R.: Osmoregulation and water balance in the springhare (Pedetes capensis). J. Comp. Physiol. [B] 169:1-10, 1999.
Puschmann, W.: Zootierhaltung. Vol. 2, Säugetiere. VEB Deutscher Landwirtschaftsverlag Berlin, 1989.
Rosenthal, M.A. and Meritt, D.A.: Hand-rearing springhaas Pedetes capensis at Lincoln Park Zoo, Chicago. Intern. Zoo Yearb. 13:135-137, 1973.
Simpson. G.G.: The principles of classification and a classification of mammals. Bull. Amer. Museum Nat. Hist. 85:1-350, 1945.
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