Saint Bathans mammal

Source: Wikipedia, the free encyclopedia.

The Saint Bathans mammal is a currently unnamed extinct primitive

seals are the only non-introduced mammals in the otherwise bird-dominated faunas.[1]

Discovery

The Saint Bathans mammal is currently represented by three specimens in Te Papa: NMNZ S.40958, NMNZ S.41866, and NMNZ S.42214, composed of two lower jaw fragments and a femur respectively. It was part of an assemblage of fossils recovered in Saint Bathans in 1978, in what would later be understood to be the Bannockburn Formation (Manuherikia Group), and first described in 2006.[1]

Description

Like most small mammal fossils, the Saint Bathans mammal material is rather incomplete, with only a lower jaw fragment and femur being known.

The lower jaws are toothless, though the presence of deep tooth sockets suggests that they were toothed in life and that the teeth were lost post-mortem. They bear a long fused

canine and two double-rooted premolars
.

The femur possesses a round

neck, oriented slightly dorsomedially with respect to the long axis of the shaft, and separated from the greater trochanter by a marked trough. The alignment of the femur in life is hard to ascertain, but it is thought that the animal had a semi-sprawling stance, more abducted than in therian mammals but nowhere near as much as in monotremes
.

Phylogeny

Because of the incomplete material, it is very hard to understand the position of this taxon within

multituberculates, on the basis of its femoral anatomy. As the phylogeny of non-therian
mammals has undergone multiple shifts since its description, new studies might be necessary.

Ecology

The Bannockburn Formation depicts a warm temperate or subtropical lakeside environment, surrounded by herbaceous

Besides the Saint Bathans mammal, this fauna also includes

vesper bat
and several currently unclassified species, also existed.

References

  1. ^ a b Worthy, Trevor H.; Tennyson, Alan J. D.; Archer, Michael; Musser, Anne M.; Hand, Suzanne J.; Jones, Craig; Douglas, Barry J.; McNamara, James A.; Beck, Robin M. D. (2006). "Miocene mammal reveals a Mesozoic ghost lineage on insular New Zealand, southwest Pacific". PNAS. 103 (51): 19419–19423.
    PMID 17159151
    .
  2. ^ Worthy, Trevor H.; et al. (2013). Miocene fossils show that kiwi (Apteryx, Apterygidae) are probably not phyletic dwarves (PDF). Paleornithological Research 2013, Proceedings of the 8th International Meeting of the Society of Avian Paleontology and Evolution. Retrieved 9 March 2014.
  3. ^ Hand, Suzanne J.; Worthy, Trevor H.; Archer, Michael; Worthy, Jennifer P.; Tennyson, Alan J. D.; Scofield, R. Paul (2013). "Miocene mystacinids (Chiroptera, Noctilionoidea) indicate a long history for endemic bats in New Zealand". Journal of Vertebrate Paleontology. 33 (6): 1442–1448.
    S2CID 85925160
    .
  4. ^ Hand, Suzanne J.; Beck, Robin M. D.; Archer, Michael; Simmons, Nancy B.; Gunnell, Gregg F.; Scofield, R. Paul; Tennyson, Alan J. D.; De Pietri, Vanesa L.; Salisbury, Steven W.; Worthy, Trevor H. (2018). "A new, large-bodied omnivorous bat (Noctilionoidea: Mystacinidae) reveals lost morphological and ecological diversity since the Miocene in New Zealand". Scientific Reports. 8 (1): 235.
    PMID 29321543
    .