Sphenodon guntheri (Tuatara)
| Tuatara | ||||||||||||||||
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Sphenodon punctatus (Gray, 1842) | ||||||||||||||||
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Hatteria punctata, Gray 1842 |
The tuatara is an amniote[1] of the family Sphenodontidae,[2] native to and found only in New Zealand. The two species of tuatara are the only surviving members of the Sphenodontidae. Related to lizards and snakes, tuatara are neither one.[3] [4][5]
Tuatara survive on about 30 islands off the New Zealand coast and until recently all populations were regarded as belonging to the species Sphenodon punctatus. At one time, during the 19th century, S. guntheri was delineated as a separate species on morphological grounds. Their status as a separate species was rescinded in the late 70s early 80s. Genetic analysis of the blood allozymes in the majority populations of tuatara later revealed that the population on North Brother Island was sufficiently distinct to justify reinstatement as the species S. guntheri.[6]
Characteristics
Adult female is smaller than adult female S. punctatus.
Habitats
North Brother Island, Cook Straits
Nesting habits
S. guntheri do not nest yearly and lay a smaller clutch of eggs than that of S. punctatus., ranging from 4-8 eggs per clutch with a mean of 6.5±0.6 .
Nest are dug early-mid November and females sometimes re-use the same sites year to year. Nesting S. guntheri spend several nights or weeks digging a nest chamber in the soil. They are distinct from those of seabirds in that they are narrow (8-10 cm) and shallower (about 10 cm when completed) are surrounded by freshly piled dirt and the absence of bird excrement or feathers.
Nests are always dug in sunny, open (unvegetated) patches of soil or soil/gravel. Such sites are few on North Brother Island and usually associated with lighthouse operations on the island. Habitat alteration for lighthouse operations date to the late 19th century and they seem to be providing more nesting habitat.
S. guntheri eggs are ovoid, white and soft-shelled, have a mean mass of 4.9±0.2 g [7] and most are completely calcified.[6]
Notes
- ↑ Amniota University of California Museum of Paleontology
- ↑ Introduction to the Sphenodontidae University of California Museum of Paleontology
- ↑ Diapsida University of California Museum of Paleontology
- ↑ Sphenodon punctatus Musico, B. (1999). On-line, Animal Diversity Web. University of Michigan Museum of Zoology Accessed December 29, 2007
- ↑ Sphenodontidae Paleobiology Database
- ↑ 6.0 6.1 Nesting and Clutch Size of Tuatara (Sphenodon Guntheri) on North Brother Island, Cook Strait Derek Brown Susan F. Schafer Tuatara : Journal of the Biological Society. Volume 31, Issue 1, July 1991
- ↑ range 3.0-5.8 g