Zygomaturinae

Zygomaturinae
Zygomaturus Tasmanicus
Temporal occurrence
Oligocene to Pleistocene
Locations
Australia , New Guinea
Systematics
Marsupials (Marsupialia) Australidelphia Diprotodontia Diprotodontoidea Diprotodontidae Zygomaturinae
Scientific name
Zygomaturinae
Stirton , Woodburne & Plane , 1967

The Zygomaturinae are a subfamily within the Diprotodontidae family and part of the Australian-New Guinea megafauna . Animals belonging to this subfamily existed from the late Oligocene to the late Pleistocene and were among the largest marsupials in geological history.

etymology

The Zygomaturinae are named after the type genus Zygomaturus in combination with the ending “ -inae ”, which assigns the taxon the rank of subfamily according to the rules of the ICZN code . The genus Zygomaturus in turn takes its name from its unusually strong zygomatic arch ( Arcus zygomaticus ).

Upper jaw fragment from Neohelos with teeth P ³ -M ³ ; P ³ (at the top in row A) with a clear parastyle

features

Zygomaturinae were small ( Nimbadon species) to large animals. The best known species, Zygomaturus trilobius , was about the size of a domestic cattle , the medium-sized Silvabestius species about the size of a sheep . The relatively small Maokopia species weighed around 100 kg.

The zygomaturinae had complex upper third premolars ( P ³ ) with three, four, or five cusps. An additional cusp, called a parastyle, is of particular importance, which is located in the front area and somewhat separated from the rest of the P ³ tooth crown. This feature occurs in all zygomaturinae in a more or less pronounced form.

Paleecology

The Zygomaturinae were believed to have been leaf eaters . There is no evidence that some species were grazers. From the Upper Oligocene to the Middle Miocene they predominantly inhabited rainforests , from the Upper Miocene to the Pleistocene, on the other hand, they lived in moist to dry hardwood forests .

The habitat change is due to the plate tectonic development of Australia. From around the Middle Miocene onwards, the Australian continental shelf collided with the plate mosaic of Southeast Asia, as a result of which mighty mountain ranges formed in the area of ​​today's island of New Guinea and the rainforests of northern and central Australia pushed into their rain shadows . The vegetation adapted to the new conditions and the Zygomaturinae also got along with it.

Systematics

Zygomaturinae    Maokopia      Hulitherium      unnamed genus      Zygomaturus      unnamed genus      Colopsis      Neohelos      Plaisiodon      Colopsoides      Nimbadon      Alkwertatherium      Silvabestius  ?    Raemeotherium

Internal systematics of the Zygomaturinae according to Black & Mackness, 1999.

The Zygomaturinae are next to the Diprotodontinae the second subfamily of the Diprotodontidae . The taxon comprises 13 genera with a total of 25 species (as of 1999) and thus represents the most diverse group within the Diprotodontidae.

Traditionally, Zygomaturinae are considered to be the most primitive Diprotodontids, but this is not certain. In addition, in 1990 , Murray saw in his first description of Alkwertatherium further problems in the analysis of the phylogenetics of Diprotodontiden. The skull morphology of the Zygomaturinae is quite variable and the molars of some species of Zygomaturinae and Diprotodontinae overlap in size and morphology.

The adjacent cladogram shows the internal systematics of the Zygomaturinae according to Black & Mackness , 1999.

The assignment of the genus Raemeotherium to the Zygomaturinae is not entirely certain, since the form of the decisive third upper premolar in this genus is still unknown. As the oldest and most primitive representatives of zygomaturinae the species of the genus are accordingly silvabestius from the Upper Oligocene to Miocene Süßwasserkalken the Riversleigh - fossil deposit in northwest Queensland .

According to Stirton et al. , 1967 the primary distinguishing feature of the subfamily Zygomaturinae is a large, complex, bulbous premolar P ³ with four or five cusps. However, the authors already suspected that basal representatives of the subfamily with three-humped premolars P ³ might have existed and that the zygomaturinae might have developed from basal representatives of the Diprotodontidae . This assumption was later confirmed with the discovery of Alkwertatherium and Silvabestius .

literature

• JA Long, M. Archer, T. Flannery & S. Hand: Prehistoric Mammals of Australia and New Guinea, one hundred million years of evolution . Johns Hopkins University Press, Baltimore / London 2002, ISBN 0-8018-7223-5 .

Individual evidence

1. ↑ Long et al., P. 98.
2. ↑ Long et al., P. 96.
3. ↑ ^{a b} Long et al., P. 97.
4. ↑ Long et al., P. 93.
5. ↑ ^{a b} Long et al., P. 91.
6. ↑ ^{a b c} P. Murray: Alkwertatherium webbi, a New Zygomaturine Genus and Species from the Late Miocene Alcoota Local Fauna, Northern Territory (Marsupialia: Diprotodontidae). In: The Beagle, Records of the Northern Territory Museum of Arts and Sciences , Volume 7, Number 2, 1990, pp. 53-80, ( digitized ).
7. ↑ M. Archer, R. Arena, M. Bassarova, K. Black, J. Brammall, B. Cooke, Ph. Creaser, K. Crosby, A. Gillespie, H. Godthelp, M. Gott, SJ Hand, B. Kear, A. Krikmann, B. Mackness, J. Muirhead, A. Musser, T. Myers, N. Pledge, Y. Wang & St Wroe: The evolutionary history and diversity of Australian mammals. In: Australian Mammalogy , Volume 21, 1999, pp. 1-45, ( digitized ).
8. ^ ^{A b c} K. Black & B. Mackness: Diversity and Relationships of Diprotodontoid Marsupials. In: Australian Mammalogy , Volume 21, 1999, pp. 20-21, ( digitized )
9. ↑ SJ Hand, M. Archer, H. Godthelp, TH Rich & NS Pledge: Nimbadon, a new genus and three new species of Tertiary zygomaturines (Marsupialia: Diprotodontidae) from northern Australia, with a reassessment of Neohelos. In: Memoirs of the Queensland Museum , Volume 33, Number 1, 1993, pp. 193-210, ISSN  0079-8835 , ( digitized ).
10. ↑ ^{a b} K. Black & M. Archer: Silvabestius gen. Nov., A primitive zygomaturine (marsupialia, diprotodontidae) from Riversleigh, Northwestern Queensland. In: Memoirs of the Queensland Museum , Volume 41, Number 2, 1997, pp. 193-208, ( digitized ).
11. ↑ P. Murray, D. Megirian, Th. Rich, M. Plane, K. Black, M. Archer, S. Hand & P. ​​Vickers-Rich: Morphology, systematics and evolution of the marsupial genus Neohelos Stirton (Diprotodontidae, Zygomaturinae ). In: MAGNT Research Report , Volume 6, 2000, 48 pages, ISSN  1447-1981 , ( digitized version ).