Tympanocryptis is a genus of Australian lizards in the family Agamidae, commonly known as earless dragons.

Description

The genus Tympanocryptis has the following characters. The tympanum is hidden (hence the common name earless dragon). The body is depressed, and it is covered dorsally with heterogeneous scales. There is no dorsal crest. There is no gular sac, but a strong transverse gular fold is present. The tail is round in cross section. There is a preanal pore on each side, which sometimes is absent in females. In most species there are no femoral pores, Tympanocryptis tetraporophora being an exception.

Species

The following 23 species are recognized as being valid.

  • Tympanocryptis argillosa – claypan earless dragon
  • Tympanocryptis centralis – central Australian earless dragon
  • Tympanocryptis cephalus – blotch-tailed earless dragon
  • Tympanocryptis condaminensis – Condamine earless dragon (previously part of T. pinguicolla)
  • Tympanocryptis diabolicus – Hamersley pebble-mimic dragon
  • Tympanocryptis fictilis – Harlequin earless dragon
  • Tympanocryptis fortescuensis – Fortescue pebble-mimic dragon
  • Tympanocryptis gigas – Gascoyne pebble-mimic dragon
  • Tympanocryptis houstoni – Houston's earless dragon
  • Tympanocryptis intima – gibber earless dragon
  • Tympanocryptis lineata – lined earless dragon or Canberra grassland earless dragon (Canberra population previously part of T. pinguicolla) These species are rarely found outside native temperate grasslands, and does not adapt well to changed environments, primarily due to the lack of food diversity found outside their native habitat. T. pinguicolla may already be extinct due to the heavy degradation that grasslands have received in Victoria, with the last known confirmed sighting being made in 1969. According to Nelson, they "[m]ay survive short-term disturbance from fire." that researchers Professor Stephen Sarre and Dr Lisa Doucette from the University of Canberra's Institute for Applied Ecology had succeeded in breeding the Canberran T. lineata in captivity, and had also hatched eggs gathered from field studies, with around 60 hatchlings being born. In June 2011, Professor Sarre's team won a four-year funding grant from the Australian Research Council to research and potentially save the species from extinction, and find a cause for the species recent collapse in numbers, thought to be associated with 10 years of drought in the species' range. In 2019, ecologist Brett Howard from the ACT Parks and Conservation Service said that "grassland earless dragons are at risk of extinction in the near future even though much has been done to improve their survival chances in the past five years." He then listed the threats posed to this species, saying "this species has suffered declines in recent decades likely due to a combination of drought, overgrazing and climate change."

References

  • Tympanocryptis. Zipcode Zoo.
  • Grassland Earless Dragon.

Further reading

  • Peters W (1863). "Eine Übersicht der von Hrn. Richard Schomburgk an das zoologische Museum eingesandten Amphibien, aus Buchsfelde bei Adelaide in Südaustralien ". Monatsberichte der Königlichen Preussischen Akademie der Wissenschaften zu Berlin 1863: 228–236. (Tympanocryptis, new genus, p. 230). (in German).