Petaurus ariel (Cremona & Baker & Cooper & Montague-Drake & Stobo-Wilson & Carthew, 2021)

Cremona, Teigan, Baker, Andrew M., Cooper, Steven J. B., Montague-Drake, Rebecca, Stobo-Wilson, Alyson M. & Carthew, Susan M., 2021, Integrative taxonomic investigation of Petaurus breviceps (Marsupialia: Petauridae) reveals three distinct species, Zoological Journal of the Linnean Society 191, pp. 503-527 : 513-516

PETAURUS ARIEL (GOULD, 1842)

Recommended common name: Savanna glider.

Remarks: Originally designated as Belidea ariel by Gould (1842) before being synonymized within breviceps by Waterhouse(1846). Petaurus breviceps ariel was designated as a subspecies by Thomas (1922) and recognized by Iredale and Troughton (1934) and subsequent authors (summarized in: Jackson & Thorington, 2012).

Etymology: The species name ariel refers to ‘a light and graceful spirit of the air’, after a spirit in Shakespeare’s play The Tempest.

Type specimen: Lectotype: NHMUK 1842.5 .26.1, adult female skull, dentary and skin; lodged 26 May 1842 by John Gould from Port Essington , Northern Territory. Possibly collected by Mr Gilbert. Figure 11 depicts a photograph of the dorsal and ventral views of the specimen study skin and Figure 12 depicts features of the skull and dentary of the lectotype specimen.

Type locality: Port Essington is located within Garig Ganuk Barlu National Park on the Cobourg Peninsula. The peninsula is located on the north-west tip of Arnhem Land , 350 km east of Darwin in the Northern Territory, Australia (–11.335°, 132.138°). Live trapping was conducted near the lectotype locality as part of the present study, and we collected 11 tissue samples from wild caught individuals near the lectotype locality .

Distribution: The species is widely distributed across Northern Australia from the Gulf of Carpentaria to the Coast of the Kimberley and on several offshore islands. A specimen from Lawn Hill in Queensland

demonstrates the extent of the distribution of the species into western Queensland.

Diagnosis: Petaurus ariel displays substantial body size variation across its range. In the northern, more coastal parts of its range it is likely the smallest of all Australian Petaurus spp. However, in the southern, more arid parts of its range it can be more than double in size (Stobo-Wilson et al., in press). Petaurus ariel appears to be the only species that occurs across the Top End of the Northern Territory and into Western Australia and thus it can be most easily distinguished based on location ( Fig. 3). Petaurus ariel can be distinguished from its closest genetic relatives, P. gracilis and P. norfolcensis , by substantial size differences, with P. ariel being considerably smaller ( Fig. 10). A distinctly cylindrical, thinly furred tail with little variation in fur length from the base to the tip also differentiates P. ariel . Compared to P. breviceps , and to a lesser extent P. notatus , P. ariel has a more clearly defined dorsal stripe, often extending all the way to a point between the hind legs. Throughout its range, P. ariel tends to have a stronger warm tone in its ventral fur when compared to P. breviceps and P. notatus .

The skulls of P. ariel have a significantly smaller maximum skull length, intra-orbital width, rostral height and rostral width than skulls of both P. breviceps and P. notatus ( Table 4). A majority of tooth measurements were similar across all three species.

DESCRIPTION OF LECTOTYPE 1842.5.26.1 OF PETAURUS BREVICEPS ARIEL

External measurements: Hindfoot length: 22 mm; hand: 19 mm; head–body length: 155 mm; tail–vent length: 155 mm (tail appears incomplete, conversions from Gould’s measurements suggest that the tail was 178 mm); ear length: 17 mm.

Pelage: Colours of the Petaurus breviceps ariel lectotype are as follows. Dorsal body coloration varies from light grayish olive to citrine drab. A mummy brown middorsal stripe commencing at a point 4 mm posterior between the anterior edge of the eyes and extending posteriorly to a point over the rump, fading 25 mm from the base of the tail. The mid-dorsal stripe is irregular in width: 4 mm wide between the ears, 5 mm at midshoulder blades, 2 mm at the hips and fading over the rump. Fur of the mid-back is 12 mm long with colour varying over its length. The basal 8 mm is smoke grey, median 2 mm hair brown and apical 2 mm tipped pale smoke grey. The dorsal body is washed with olive buff with the wash being most pronounced over the rump but not giving a pronounced dappled appearance.

The head is furred with light greyish olive-citrine drab and a ring of fuscous black encircles the eye in a defined eye ring. Fuscous fur at the base of the pinna forms an incomplete circle, extending dorsally from the anterior edge of the pinna, adjoining the dark fur encircling the eye, to the ventral tragus. The inner surface and the distal 14 mm of the outer surface of the pinnae are sparsely furred with only scattered dark hairs visible. The pinnae of living animals are flesh-pink tending to fuscous black at the outer edge. A patch of deep olive buff fur on the posterior edge of the pinna forms a conspicuous tuft.

Dorsally, the gliding membrane or patagium is fringed along its length by a thickly furred 3–4 mm band of greyish olive fur (hairs 4 mm long). The patagium is sepia coloured and becomes interspersed with dorsal body fur closer to the medial surface of the patagium. Ventrally, the patagium is fringed in a 4 mm band of deep olive buff coloured fur from the claw of digit 5 to the ankle. More medially, this band is partially overlaid by drab fading to cream buff across the surface of the patagium with no distinct band. The soft ventral fur is cream buff lightened by a wash of light buff tending to chamois at the base of the throat.

A thin covering of fuscous hairs is present on the dorsal surface of the forefeet digits. Hindfeet are slightly more thickly covered chaetura drab, which gently contrasts with a less pronounced ‘mitten’ of sepia over the metatarsals extending up to the inner posterior region of the thigh in a triangular stripe almost to the top of the thigh. Longer drab fur (13-mm long hairs) forms a less pronounced fringe on the outer surface of the thighs.

The tail is thinly drab furred and may be incomplete in the specimen given its short length and abrupt tip (163 mm). The distal 53 mm tip of the tail is blackish brown on both dorsal and ventral surfaces. The proximal 110 mm portion of the tail is dorsally coloured drab. The ventral surface of the tail is deep olive buff. Fur length 20 mm from the base of the tail is 16 mm long, and 40 mm from the tail tip is 11 mm long.

The lectotype skin is depicted in Figure 11. Note that males exhibit naked, ovoid glandular patches on the crown of the head within the black head stripe and at the base of the throat.

Vibrissae: Approximately 16 black mystacial vibrissae occur on each side and these are up to 23 mm long. Supra-orbital vibrissae (2); genals (3).

Pes and manus: The claws of the fore- and hindfeet are relatively large with maximum chord length of digit 4 and 5 claws approx. 9 mm. Digit 4 is the longest digit of manus or pes, and digit 4> 5> 3> 2> 1.