Galanarla

Galanarla is a potentially dubious genus of balbarid kangaroo from the Late Oligocene that was found at the Riversleigh World Heritage Area, Australia.

Galanarla Temporal range: Late Oligocene PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Marsupialia
Order:	Diprotodontia
Family:	†Balbaridae
Genus:	†Galanarla Flannery et al., 1982
Type species
†Galanarla tessellata Flannery et al., 1982

History and naming

In 1982, Tim Flannery, Michael Archer and Michael Plane named and described a new genus and species of macropod, Galanarla tessellata. The holotype specimen, QM F10644, is a partial left dentary collected from D site at the Riversleigh World Heritage Area, northwestern Queensland. The authors also referred an unworn molar, and tentatively assigned numerous premaxilla and teeth fragments to the taxon.^[1]

The generic name is a combination of the Waanyi words for “river” (Gala) and “rock wallaby” (Narlee), referring to the fluviatile deposit it was found in and to the fossils representing a fossilised macropod. The specific name stems from the Latin word for "mosaic". This is in reference to the mosaic nature of traits exhibited by this taxon.^[1]

Description

Galanarla shares many similarities with the balbarids Ganawamaya and Nambaroo. It possesses a dentary that lacks flexion below the molar row. The opening for the masseteric canal is smaller than those of bulungamayines. Although not preserved, the third lower premolar does not align with the molar row and instead, bends buccally (towards the cheek). It had lophodont molars with large ridges.^[1][2]

Classification

When first described in 1982, Tim Flannery and colleagues classified Galanarla as a member of the Macropodidae. The authors weren’t able to assign it to a particular subfamily as it shared affinities with balbarines, macropodines and sthenurines.^[1] Seven years later, in 1989, Flannery thought it was a macropodine.^[3] More recent studies, however, have referred it to either Balbarinae or Balbaridae incertae sedis.^[4][5] Butler et al. (2018) limited Galanarla to the holotype specimen and considered it a nomen dubium due to its poor preservation.^[2]

Paleobiology

Galanarla is known only from a single site at the Riversleigh World Heritage Area, site D. The age of the site was originally interpreted as middle Miocene, although it is now known to be Late Oligocene.^[1][6] At the time, the Riversleigh area would have been covered in woodland or open forest.^[7] These forests would have been dominated by trees or shrubs from the family Casuarinaceae.^[8] Patches of rainforest may have also been present, specifically around pools or along watercourses.^[9] Galanarla lived alongside other macropods like Bulungamaya and Gumardee.^[1]

Galanarla is thought to have been a mixed feeder, being able to both graze and browse.^[10]