Evolution of Macropodidae

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The Macropodidae are an extant family of marsupial with the distinction of the ability to move bipedally on the hind legs, sometimes by jumping, as well as quadrupedally. They are herbivores, but some fossil genera like Ekaltadeta are hypothesised to have been carnivores. [1] The taxonomic affiliations within the family and with other groups of marsupials is still in flux. [2] Macropodids are considered to be the most diverse group of marsupial herbivores ever to have evolved, and have been the subject of more phylogenetic studies than any other marsupial family. [3]

Contents

Earliest macropods

In Australia, there are various fossil taxa described from the Oligocene–Miocene boundary from Riversleigh of Queensland, Lake Tarkarooloo, Namba, Etabunna and Wipajiri formations of South Australia. [4] No fossils Macropodidae have been found that predate the Late Oligocene. [2] Using 12S ribosomal RNA transversions, the Hypsiprymnodontidae were found to have diverged from the other macropodids approximately 45 million years ago, the Macropodinae and Potoroinae about 30 million years ago, and Dorcopsis and Dorcopsulus of New Guinea about 10 million years ago, when they inhabited the Australian mainland. [5] The fossils that have been found are a plesiomorphic form of kangaroo, indicating it is likely that the family dates back even earlier. The earliest post-K–T extinction is the Tingamarra fauna of the Eocene, but no taxa assigned to the Macropodidae have been found in these deposits, and these Eocene species are of uncertain relationship to any Oligocene taxa.[ citation needed ]

All current families are represented in these Oligocene deposits, but not all sub-families, and those that are not (Sthenurinae, Macropodinae) are found during the rapid evolution of kangaroos in Mid-Miocene to Late Miocene deposits. Of those that are, the hypsiprymnodontid genus Ekaltadeta and isolated molars from the genus Hysiprymnodon are known. Of the Macropodidae, only the plesiomorphic subfamily Bulungamayinae is known, represented by Wakiewakie lawsoni, Gumardee pascuali, Purtia and Palaeopotorous priscus. [2] There are Potoridae, represented by Bettongia moyesi, from the Middle Miocene. The last family from the Oligocene–Miocene boundary consists of species that could be described as a plesiomorphic macropodoids and are ascribed to the extinct family Balbaridae in the genera Nambaroo and Balbaroo . [2]

Nambaroo occurs in fossil formations from the Bullock Creek fauna, which are found in freshwater limestone of the Camfield beds. [6] Other balbarids have been found in Riversleigh and Alcoota fossil deposits. [7] Another family that dates back to this era is the Hypsiprymnodontidae, which includes the two subfamilies Propleopinae and Hypsiprymnodontinae. [2] Both subfamilies have genera of Oligocene age, with the genus Hypsiprymnodon extending that far. [2]

Balaridae is primitive in dental morphology and shares features seen in common with only Hypsiprymnodon moschatus , some other Phalangeroidea and primitive macropodines. [7] These features discount all potoroids from being ancestors to the macropodids on these structural grounds. They consist of a compressed trigonid on the first lower molar, straight molar row and strongly twisted dentary. [7] Primitive macropodines have the straight molar row in common. [7] Ekaltadeta also has plesiomorphic features in that the dental canal and masseteric canal are separated anteriorly, below premolar three and the first molar, with the masseteric canal terminating in a cul-de-sac. This it shares with no other macropodids. Another feature that it only shares with Hypsipromnodon is that the lower second premolar is not evicted by the third premolar. [8]

Pleistocene developments

Extinctions

Balbaridae, Bulungamayinae, Sthernuridae all became extinct by the Pleistocene. The reason for their extinctions are unknown but hypotheses include outdated model, climate and habitat changes. Some species of Sthenurus could have been around when humans arrived in Australia, but by this time they were already progressing towards extinction. The taxonomic affiliations within the family and with other groups of marsupials is still in flux. [2]

Current speciation

According to John H. Kaufmann, the major evolutionary trends in the family have been moving towards a larger size and grazing habits. Meanwhile, the trends toward diurnality and group living have had "more modest results". [9]

Related Research Articles

<span class="mw-page-title-main">Macropodidae</span> Family of marsupial mammals

Macropodidae is a family of marsupials that includes kangaroos, wallabies, tree-kangaroos, wallaroos, pademelons, quokkas, and several other groups. These genera are allied to the suborder Macropodiformes, containing other macropods, and are native to the Australian continent, New Guinea and nearby islands.

<span class="mw-page-title-main">Peramelemorphia</span> Order of mammals

The order Peramelemorphia includes the bandicoots and bilbies. All members of the order are endemic to Australia-New Guinea and most have the characteristic bandicoot shape: a plump, arch-backed body with a long, delicately tapering snout, very large upright ears, relatively long, thin legs, and a thin tail. Their size varies from about 140 grams up to 4 kilograms, but most species are about one kilogram.

<span class="mw-page-title-main">Thylacinidae</span> Extinct family of marsupials

Thylacinidae is an extinct family of carnivorous marsupials from the order Dasyuromorphia. The only species to survive into modern times was the thylacine, which became extinct in 1936.

<span class="mw-page-title-main">Musky rat-kangaroo</span> Species of marsupial

The musky rat-kangaroo is a small marsupial found only in the rainforests of northeastern Australia. First described in the later 19th century, the only other species are known from fossil specimens. They are similar in appearance to potoroos and bettongs, but are not as closely related. Their omnivorous diet is known to include materials such as fruit and fungi, as well as small animals such as insects and other invertebrates.

<span class="mw-page-title-main">Hypsiprymnodontidae</span> Family of marsupials

The Hypsiprymnodontidae are a family of macropods, one of two families containing animals commonly referred to as rat-kangaroos. The single known extant genus and species in this family, the musky rat-kangaroo, Hypsiprymnodon moschatus, occurs in northern Australia. During the Pleistocene, this family included the megafauna genus Propleopus.

<span class="mw-page-title-main">Thylacoleonidae</span> Extinct family of marsupials

Thylacoleonidae is a family of extinct carnivorous diprotodontian marsupials from Australia, referred to as marsupial lions. The best known is Thylacoleo carnifex, also called the marsupial lion. The clade ranged from the Late Oligocene to the Late Pleistocene, with some species the size of a possum, while members of Thylacoleo reached sizes comparable to living big cats.

<i>Wakaleo</i> Extinct genus of marsupials

Wakaleo is an extinct genus of medium-sized thylacoleonids that lived in Australia in the Late Oligocene and Miocene Epochs. Although much smaller than its close relative, the marsupial lion, Wakaleo would have been a successful hunter. It had teeth specially designed for cutting and stabbing. The genus is from an extinct family of Vombatiformes, so it is distantly related to the herbivorous wombats.

<i>Ekaltadeta</i> Extinct genus of marsupials

Ekaltadeta is an extinct genus of marsupials related to the modern musky rat-kangaroos. Ekaltadeta was present in what is today the Riversleigh formations in Northern Queensland from the Late Oligocene to the Miocene, and the genus includes three species. The genus is hypothesized to have been either exclusively carnivorous, or omnivorous with a fondness for meat, based on the chewing teeth found in fossils. This conclusion is based mainly on the size and shape of a large buzz-saw-shaped cheek-tooth, the adult third premolar, which is common to all Ekaltadeta.

Yarala is a genus of fossil mammals that resemble contemporary bandicoots. The superfamily Yaraloidea and family Yaralidae were created following the discovery of the type species Yarala burchfieldi in 1995, on the basis that it lacks synapomorphies that unite all other peramelemorphian taxa.

<span class="mw-page-title-main">Macropodiformes</span> Suborder of marsupials

The Macropodiformes, also known as macropods, are one of the three suborders of the large marsupial order Diprotodontia. They may in fact be nested within one of the suborders, Phalangeriformes. Kangaroos, wallabies and allies, bettongs, potoroos and rat kangaroos are all members of this suborder.

<span class="mw-page-title-main">Bettong</span> Genus of marsupials

Bettongs, species of the genus Bettongia, are potoroine marsupials once common in Australia. They are important ecosystem engineers displaced during the colonisation of the continent, and are vulnerable to threatening factors such as altered fire regimes, land clearing, pastoralism and introduced predatory species such as the fox and cat.

<i>Nimbacinus</i>

The genus Nimbacinus contains two species of carnivorous, quadrupedal marsupials in Australia both of which are extinct:

Nambaroo is an extinct genus of macropod marsupial from the late Oligocene to the early Miocene of Australia.

<span class="mw-page-title-main">Balbaridae</span> Extinct family of marsupials

Balbaridae is an extinct family of basal Macropodoidea. The synapomorphies are divided into two areas, the dental and cranial. The dental area of this taxa can be described as having the molar lophodont and brachyodont with a hypolophid formed by lingually displaced component of posthypocristid and linked to a buccal crest from the entoconid. Molars have a hypocingulid, first lower molar compressed with the "forelink" absent. First incisor with lingual and dorsal enamel ridgelets. The third lower premolar of some taxa have a posterobuccal cusp. The skull is defined by four shared characteristics, a large sinuses, postorbital lateral constriction of the skull, a hypertrophy of the mastoid processes and no auditory bulla formed by an inflated tympanic wing of the alisphenoid.

Ganguroo is a genus of fossil macropods found at Riversleigh in Australia, material dating from the Middle to Late Miocene Epoch. The type species of the genus is Ganguroo bilamina, published in 1997. Two recently described species, Ganguroo bites and Ganguroo robustiter, have also been placed in this genus.

Cookeroo is a genus of extinct kangaroos from the Late Oligocene and Early Miocene found in fossil deposits from the Riversleigh World Heritage Area, in Australia. The genus includes two species, C. bulwidarri and C. hortusensis.

<i>Microleo</i> Extinct genus of marsupials

Microleo attenboroughi is a very small species of the Thylacoleonidae family of marsupials from the Early Miocene of Australia, living in the wet forest that dominated Riversleigh about 18 million years ago. The genus Microleo is currently known from a broken palate and two pieces of jaw, containing some teeth and roots that correspond to those found in other species of thylacoleonids. The shape and structure of the blade-like P3 tooth, a premolar, distinguished the species as a new genus. It was found in Early Miocene-aged deposits of the Riversleigh fossil site in Queensland, regarded as one of the most significant palaeontological sites yet discovered, and named for the naturalist David Attenborough in appreciation of his support for its heritage listing. The anatomy of Microleo suggests the genus is basal to all the known thylacoleonids, known as the marsupial lions, although its relative size prompted one discoverer to describe it as the "feisty" kitten of the family.

Hypsiprymnodon karenblackae is a fossil species describing a small marsupial extant in Australia during the Early to Middle Miocene Epoch. The material was collected at the Australian Fossil Mammal Sites (Riversleigh). The taxon was published in 2014, along with several other new species of the genus Hypsiprymnodon, known as musky rat-kangaroos. The morphology of the teeth suggest it existed in a wet rainforest environment, similar to the ecological conditions of the extant species, the musky rat-kangaroo. The type specimen was collected at the Camel Sputum site, classified as a Faunal Zone B (Miocene) deposit at Riversleigh in northwestern Queensland, The epithet is for Dr. Karen Black's contribution to palaeontology in Australia, especially the Riversleigh fossils.

<i>Propalorchestes</i> Extinct genus of marsupials

Propalorchestes is a fossil genus of palorchestid marsupial that existed in Australia during the Miocene epoch.

Lekaneleo roskellyae is a fossil species of carnivorous marsupial that existed during the early Miocene in Australia. Once allied to the type species of the genus Priscileo, later placed as Wakaleo pitikantensis, "Priscileo" roskellyae was subsequently transferred to its own genus Lekaneleo.

References

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  2. 1 2 3 4 5 6 7 Kear. B. P., Cooke. B. N . A review of macropodoid (Marsupialia) systematics with the inclusion of a new family. Memoirs of the Association of Australasian Palaeontologists 25, 83-101. ISSN 0810-8889
  3. PRIDEAUX, GAVIN J.; WARBURTON, NATALIE M. (2010-07-26). "An osteology-based appraisal of the phylogeny and evolution of kangaroos and wallabies (Macropodidae: Marsupialia)". Zoological Journal of the Linnean Society. 159 (4): 954–987. doi:10.1111/j.1096-3642.2009.00607.x. ISSN   0024-4082.
  4. Cooke. B. N., "Cranial remains of a new species of Balbarine kangaroo (Marsupiala: Macropodoidea) from the Oligo-Miocene freshwater limestone deposits of Riversleigh World Heritage area, Northern Australia" Journal of Paleontology, 74(2), 2000, pp.317-326 doi : 10.1017/S0022336000031528
  5. Angela Burk, Michael Westerman, and Mark Springer "The Phylogenetic Position of the Musky Rat-Kangaroo and the Evolution of Bipedal Hopping in Kangaroos (Macropodidae: Diprotodontia)" Systematic Biology 47(3): 457 ± 474, 1998
  6. Schwartz L R S and Megirian D., "A New Species of Nambaroo (Marsupialia; Macropodoidea) from the Miocene Camfield Beds of Northern Australia with Observations on the Phylogeny of the Balbarinae", Journal of Vertebrate Paleontology 24(3):668–675, September 2004
  7. 1 2 3 4 Flannery. T, Archer. M & Plane. P 1982 "Middle Miocene Kangaroos (Macropoidea:Marsupialia) from three localities in Northern Australia, with a description of two new subfamilies". Journal of Geology and Geophysics, 7, 287-302.
  8. Archer. M. Flannery. T 1985 "Revision of the extinct giant rat kangaroo (Potoroidae:Marsupialia), with description of a new Miocene genus and species and a new Pleistocene species of Propleopus, Journal of Paleontology, Vol. 59, No 6, pp. 1331-1349.
  9. Kaufmann, John H. (1974). "The Ecology and Evolution of Social Organization in the Kangaroo Family (Macropodidae)". American Zoologist. 14 (1): 51–62. doi:10.1093/icb/14.1.51. ISSN   0003-1569.