Zalambdalestidae
Extinct family of mammals
From Wikipedia, the free encyclopedia
Zalambdalestidae is a clade of Asian eutherians occurring during the Cretaceous. Once classified as Glires, features like epipubic bones and various cranial elements have identified these animals as outside of Placentalia, representing thus a specialised clade of non-placental eutherians without any living descendants, and potentially rather different from modern placentals in at least reproductive anatomy.[1][2]
| Zalambdalestes Temporal range: | |
|---|---|
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| Zalambdalestes lechei skull and lower jaw, Museum of Evolution Warsaw. | |
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| Life reconstruction of Zalambdalestes lechei | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Clade: | Eutheria |
| Order: | incertae sedis |
| Family: | †Zalambdalestidae Gregory & Simpson, 1926 |
Taxonomy
The exact position of Zalambdalestidae within Eutheria varies, though they are generally agreed to be more basal than zhelestids.[3] Currently, the clade includes the genera Alymlestes, Anchilestes, Barunlestes, Kulbeckia, Prozalambdalestes, Zalambdalestes, Zhangolestes and Zofialestes.[4]
Palaeobiology
Zalambdaltestids were insectivores, having zalambdodont molars much as various modern insectivorous species. They are uniquely suited to a saltatorial, cursorial lifestyle, bearing long, semi-digitigrade limbs and a spinal column similar to that of modern lagomorphs.[5] Like most non-placental mammals, the presence of epipubic bones probably meant that they gave birth to poorly developed young much like modern marsupials and monotremes, though a study on multituberculate reproduction may suggest they and other early eutherians reproduced like modern placentals.[6]
A study on Zalambdalestes suggests they had a unique axial morphology. This allowed for quick prey capture, and may suggest they had spines or bristly fur in life.[7]