Ultrastructural evidence for loss of the trophoblastic layer in the chorioallantoic placenta of Australian Bandicoots (Marsupialia: Peramelidae)

Padykula, Helen A.; Taylor, J. Mary

doi:10.1002/ar.1091860303

Cited by 49 publications

(17 citation statements)

References 22 publications

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“…The bandicoot is also about the same mass as the rabbit and it produces a litter of three or four young, each weighing 0.25 g, after a gestation of 12.5 days. The embryonic vesicle of the bandicoot becomes attached to the uterine wall on Day 9 of pregnancy by fusion of fetal and maternal cells to form a true chorio-allantoic placenta (Padykula and Taylor 1976). This is very similar to the first three days of placental formation in the rabbit, which begins on Day 8 (Amoroso 1952).…”

Section: Reproductionmentioning

confidence: 71%

Australasian marsupials - to cherish and to hold

Ch¹

2001

Reprod. Fertil. Dev.

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Considerable interchange of mammals between South America and Australasia occurred during the first half of the Tertiary, including the presence of placental mammals in Australia. This challenges the old assumption that the marsupial radiation in Australia was made possible by the absence of placental competition, and suggests that two properties of marsupial organization may have favoured their survival in the increasingly arid climates that developed after the separation of Australasia from Antarctica. The basal metabolic rates of marsupials are about 70% of equivalent placentals, so their maintenance requirements for energy, nitrogen and water are lower, whereas their field metabolic rates are about the same, which means that they have a greater metabolic scope to call on when active. This may have given marsupials an advantage in semi-arid environments. The lengthy and complex lactation of marsupials enables the female to exploit limited resources over an extended period without compromising the survival of the young. Both these properties of marsupials enabled them to survive the double constraints of low fertility soils and the uncertain climate of Australia throughout the Tertiary. The arrival of people was followed first by the extinction of the large marsupials and, much later, by the wholesale decline or extinction of the small-to-medium sized species. The common factor in both extinctions may have been the constraints of marsupial reproduction.

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Section: Reproductionmentioning

confidence: 71%

Australasian marsupials - to cherish and to hold

Ch¹

2001

Reprod. Fertil. Dev.

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“…a true placenta) (Freyer, Zeller & Renfree, 2003; Padykula & Taylor, 1976), which combined with an osseous patella led to the initial suggestion that they might actually be eutherians (Reese et al, 2001). However, more recent molecular and fossil-based phylogenetic studies provide no support for that hypothesis of eutherian bandicoots (Asher, Horovitz & Sanchez-Villagra, 2004; Meredith, Westerman & Springer, 2008; Sánchez-Villagra et al, 2007; Westerman et al, 2012).…”

Section: Resultsmentioning

confidence: 99%

Evolution of the patellar sesamoid bone in mammals

Samuels

Regnault

Hutchinson

2017

PeerJ

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The patella is a sesamoid bone located in the major extensor tendon of the knee joint, in the hindlimb of many tetrapods. Although numerous aspects of knee morphology are ancient and conserved among most tetrapods, the evolutionary occurrence of an ossified patella is highly variable. Among extant (crown clade) groups it is found in most birds, most lizards, the monotreme mammals and almost all placental mammals, but it is absent in most marsupial mammals as well as many reptiles. Here, we integrate data from the literature and first-hand studies of fossil and recent skeletal remains to reconstruct the evolution of the mammalian patella. We infer that bony patellae most likely evolved between four and six times in crown group Mammalia: in monotremes, in the extinct multituberculates, in one or more stem-mammal genera outside of therian or eutherian mammals and up to three times in therian mammals. Furthermore, an ossified patella was lost several times in mammals, not including those with absent hindlimbs: once or more in marsupials (with some re-acquisition) and at least once in bats. Our inferences about patellar evolution in mammals are reciprocally informed by the existence of several human genetic conditions in which the patella is either absent or severely reduced. Clearly, development of the patella is under close genomic control, although its responsiveness to its mechanical environment is also important (and perhaps variable among taxa). Where a bony patella is present it plays an important role in hindlimb function, especially in resisting gravity by providing an enhanced lever system for the knee joint. Yet the evolutionary origins, persistence and modifications of a patella in diverse groups with widely varying habits and habitats—from digging to running to aquatic, small or large body sizes, bipeds or quadrupeds—remain complex and perplexing, impeding a conclusive synthesis of form, function, development and genetics across mammalian evolution. This meta-analysis takes an initial step toward such a synthesis by collating available data and elucidating areas of promising future inquiry.

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“…Marsupials avoid maternal immuno-rejection by giving birth after short periods of internal gestation to immature neonates that complete their early development while attached and feeding at the mother's teat (Mü ller 1969;Sharman 1973;Tyndale-Biscoe 1973;Lillegraven 1975;Tyndale-Biscoe and Renfree 1987;Hughes and Hall 1988;Renfree 1993). Exceptions to this rule include the peramelids, phascolarctids, and vombatids, which form a simple chorioallantoic placenta that integrates less extensively with maternal tissue than observed in placentals (Hill 1898(Hill , 1900Hughes and McNally 1968;Padykula and Taylor 1976;Hughes 1984).…”

Section: Marsupial Reproductionmentioning

confidence: 99%

Constraints on the Morphological Evolution of Marsupial Houlder Girdles

Sears

2004

Evolution

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Throughout their evolutionary histories, marsupial mammals have been taxonomically and morphologically less diverse than their sister taxa the placentals. Because of this, it has been proposed that the evolution of marsupials has been constrained by the functional requirements of their mode of reproduction. Marsupials give birth after short gestation times to immature neonates that immediately crawl, under the power of their precociously developed shoulder girdles, to the teat where they attach and complete their early development. Using a novel approach incorporating adult and embryological morphological data, this study is the first to both: (1) statistically support adult patterns of morphological divergence consistent with the constraint hypothesis, and (2) identify ontogenetic patterns of morphological change that demonstrate that the constraint was responsible, at least in part, for their formation. As predicted by the marsupial constraint, the shoulder girdles of adult marsupials are less diverse than those of adult placentals, and adult marsupial scapulae are less morphologically diverse than adult marsupial pelves. Furthermore, marsupials that complete an extensive crawl to the teat are restricted to a common pattern of ontogenetic scapular shape change, strongly supporting the hypothesis that the morphological development of the marsupial scapula has been limited evolutionarily by its obligate role in the crawl to the teat. Because this study establishes that ontogenetic and evolutionary morphological change is correlated within mammalian scapulae, it is probable that the marsupial constraint also restricted the morphological divergence of the scapula over evolutionary time by limiting ontogenetic change in the scapula. These findings, coupled with the importance of the shoulder girdle in mammalian locomotor specialization, support the conclusion that the low morphological diversity of marsupial forms over evolutionary time could be directly due to the constraint on marsupial morphological evolution caused by the functional requirements of the crawl to the teat.

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Ultrastructural evidence for loss of the trophoblastic layer in the chorioallantoic placenta of Australian Bandicoots (Marsupialia: Peramelidae)

Cited by 49 publications

References 22 publications

Australasian marsupials - to cherish and to hold

Australasian marsupials - to cherish and to hold

Evolution of the patellar sesamoid bone in mammals

Constraints on the Morphological Evolution of Marsupial Houlder Girdles

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