Ptenopus garrulus ( Smith, 1849 )

Ptenopus garrulus ( Smith, 1849) View in CoL sensu stricto

Figures 7 View Figure 7 , 20 A View Figure 20

Common names.

Kalahari barking gecko / Garrulous barking gecko

Afrikaans: Kalahari blafgeitjie / Grondgeitjie

Chresonymy.

Stenodactylus garrulus Smith, 1849 : Append. 6

Ptenopus garrulus View in CoL (part) – Boulenger (1885: 15), Brain (1962: 3), Haacke (1964: 3)

Ptenopus garrulus garrulus View in CoL – FitzSimons (1935: 524), Loveridge (1947: 31), Haacke (1975: 214), Haacke (1969: 89)

Ptenopus garrulus maculatus View in CoL (part) – Mertens (1955: 51), Mertens (1971: 44)

Comment.

Sir Andrew Smith did not specify the type locality of P. garrulus beyond “ sandy districts in the interior of southern Africa ” ( Smith 1849). Smith did not name specimens in his description, although FitzSimons (1937 a) later noted which specimens were the types used by Smith. Smith described type specimens as buff orange, having a spotted colour pattern and poorly or non-barred tail. Smith travelled and collected extensively in Namaqualand and briefly in southern Namibia, prior to his description of P. garrulus ( Skelton 2018) . These areas contain the three species as presently treated (Figs 2 View Figure 2 , 5 View Figure 5 ): Ptenopus adamanteus sp. nov., P. kenkenses sp. nov., and P. garrulus sensu stricto. Of these, only the P. garrulus sensu stricto commonly occurs on orange, sandy substrate, with the body colour to match. The description “ inland of South Africa ” probably rules out the coastal and near-coastal regions occupied by P. adamanteus sp. nov. Hence, the southern Kalahari in the northern or central regions of the Northern Cape Province, South Africa, most likely contain the type locality, making P. garrulus sensu stricto as presently treated, the most likely candidate for this name (see Fig. 2 View Figure 2 ). We therefore elevate the subspecies ‘ P. g. garrulus ’ to full species, and thereby exclude all species previously referred to as ‘ P. g. maculatus ’, from P. garrulus sensu stricto.

The morphological characters and colour pattern of the P. garrulus type specimens from the BMNH (1946.8.23.43–49) fall within the range of P. garrulus sensu stricto in this study (except slight deviations in IOS, typically ≤ 46 for P. garrulus sensu stricto, for two specimens: BMNH 1946.8.23.44 IOS = 48 and 1946.8.23.46 IOS = 47). Specimen BMNH 1946.8.23.47 conforms most unambiguously to these morphological characters (Fig. 4 View Figure 4 ) and typical colour pattern. Hence, we designate BMNH 1946.8.23.47 (male) as the lectotype for P. garrulus sensu stricto.

Lectotype.

BMNH 1946.8.23.47 , collected from “ sandy districts in the interior of southern Africa ” (probably Northern Cape, South Africa), by Andrew Smith between 1834 and 1836.

Paralectotypes.

BMNH 1946.8.23.43 –46, 1946.8.48 – 49, same collection details as the lectotype .

Additional material examined.

See Table S 1 for vouchered (11) and unvouchered photographed (13) specimens, DNA samples (33 available, 20 sequenced), and call recordings (23) included (total n = 44 excluding types).

Diagnosis.

A small Ptenopus ( SVL max. 53.4 mm, mean 46.6 mm, n = 22) with a moderate tail ( TL 69 % [range 50–86 %] of SVL, n = 17) and a generally slender appearance. This species is easily distinguished from P. kochi , P. carpi and P. sceletus sp. nov. by a combination of the following morphological characters: Toes extensively fringed laterally (similar to P. kochi vs. weakly fringed in P. carpi and P. sceletus sp. nov.), with fringe length roughly equal to the breadth of the toe between fringes (vs. fringe length generally less than half toe breadth in P. carpi and P. sceletus sp. nov.); having white pigmented ventral scales with some pink, unpigmented scales on the (hand / foot) soles (vs. pink, unpigmented patches also on the tail and limbs in P. kochi , and white entire in P. carpi and P. sceletus sp. nov.); having MBSR ~ 182 (range 156–202, n = 31) (vs. 187–210 in P. kochi and usually <135 in P. carpi and P. sceletus sp. nov.). It is further distinct from P. carpi and P. sceletus sp. nov. by the nasals being more swollen and the nostrils partially covered by internal projections of the upper labials, and by more-or less speckled dorsal colour pattern (vs. banded pattern in P. carpi and P. sceletus sp. nov.); from P. kochi by having fingers laterally fringed with pointed triangular scales (vs. elongated pointed scales in P. kochi ).

From congeners previously included under ‘ P. garrulus ’, P. garrulus sensu stricto is distinguished by: (when live) patches of pink, unpigmented scales on soles (vs. white pigmented in other species and white or slightly pinkish with dark brown speckles in P. kenkenses sp. nov. and P. australis sp. nov.); having higher RB / RH (~ 1.12, range 0.95–1.24, n = 10) than P. australis sp. nov. (≤ 0.97); having higher MBSR (~ 182, range 156–202, n = 31) than P. australis sp. nov., P. circumsyrticus sp. nov., and P. maculatus sensu stricto (usually <149); dorsal colour pattern relatively speckled, consisting of> 2 longitudinal rows of white spots (rows may join to form irregular bands), including 5–7 clear (but not large) dorsolateral pairs of light spots between pectoral and pelvic girdles, with indistinct dark patches not touching the white, or dark patches absent, and indistinct or no patterning on ventro-lateral sides of the face, vs. 4–5 large and distinctive paired, light, ovoid markings interspaced by distinct dark mottled patches usually touching the light markings, and ovoid patterning on ventro-lateral portions of the face being more distinctive in P. kenkenses sp. nov. (and some populations of P. adamanteus sp. nov. or P. circumsyrticus sp. nov.); toe fringes being generally more extensive (with fringe length roughly equal to the breadth of the toe between fringes) than other species (fringe length usually about half toe breadth), but similar to P. australis sp. nov.

Colouration.

In life (Fig. 7 View Figure 7 ), colouration varies with substrate colour, as in other species. The colour pattern tends to be speckled or juxtaposed with light, dark, and coloured scales, the lighter (cream or white) speckles usually tending to larger dots or asymmetrical bars in some locations. On the tail, light-and-dark bars are usually evident dorsally. Background colour forms, matching various substrate colours, include brick red, cream or grey, and grey-brown. Ventrally, animals are immaculate white, with faded dark grey or brown patterning around the lateral margins, and pinkish patches on the (hand / foot) palms / soles. Males have bright yellow, heart-shaped gular patches which may extend onto the lateral margins of the head and body, and anterior surfaces of the legs.

In preservative, the lighter colours fade to off-white or beige, and all the darker colours appear various shades of dark brown or grey. The brighter colours, especially yellow, fade completely.

Advertisement call.

The advertisement call (Figs 3 View Figure 3 , 20 A View Figure 20 ) consists of 5.4 notes (4–6) uttered in rapid succession, with a note rate of 5.28s - 1 (range 3.76–7.37). Note duration is short, 22 ms (range 16–31), and highly regular, with note 1 deviance 15 % (range 3–27 %). Inter-note intervals are short (168 ms [range 114–234]) and regular, although latter intervals can be slightly longer; inter-note interval range 14–34 %. Call density relatively low (0.13 [range 0.09–0.18]). Call duration is very short, only 0.86s (range 0.6–1.2). The basal frequency is ~ 450 Hz (range 373–508) but very soft and may be inestimable, with harmonic bands louder towards the dominant frequency at 4.2 kHz (range 3.9–5.1); a very slight lower peak frequency band is evident at around or just below half the dominant frequency (roughly 1.3–2.6 kHz, cannot always be reliably estimated). Frequency appears to modulate briefly up, then down by ~ 100 Hz with each note, or remain constant. The (human) perceived pitch tends to be higher than that of most other species. Bandwidth (90 %) is difficult to estimate consistently: approximately 0.6–8.2 kHz, usually wider than other species.

During peak chorus activity, this species calls much more frequently than most other species, the call period being very short: mean 25 s, and as low as 4 s. However, calling activity is short in most localities visited by the author, usually commencing around 20 min after sunset, and lasting only 20–40 mins. Calling may continue later if the moon is above the horizon and conditions are warm, but at an extremely decreased rate. More extensive and intensive choruses, lasting throughout the night, have been recorded shortly after rain ( Haacke 1969).

Habitat and distribution.

This is the most widespread member of the genus, occurring on sandy soils across much of arid or semi-arid (generally above 150 mm but less than 550 mm annual rainfall) southern Africa, but not in the Namib Desert or the pro-Namib (Fig. 5 View Figure 5 ). It occurs on sandy flats, interdunes, and on vegetated dunes or hummocks, but usually not on steep dunes. In one location (south of Windhoek) it was found occurring on consolidated, silty soils, but this is unusual. Calling is seasonal, taking place in the austral spring, from June in the northernmost extreme, and from September or October in the southernmost extreme of its distribution.

Natural history.

The main calling period coincides with the breeding season ( Hibbitts et al. 2012). In the northern limits of its distribution, the main breeding season appears to be between June and early September, but moves later southward (author observations). Most observations on this species were made in the southern Kalahari. Here, they breed between September and November (see Hibbitts et al. 2005, although this includes data from several Ptenopus species in addition to P. garrulus ; Hibbitts et al. 2012) and possibly until late January, as hatchlings (< 32 mm SVL) have been recorded beween October and May ( Haacke 1975), and yolked eggs were recorded within females between late August and late January ( Pianka and Huey 1978). Clutch size appears to be one egg, although a second clutch may develop shortly after the first ( Hibbitts et al. 2005). One nest was found to contain three eggs, although one or two of these may have been Pachydactylus wahlbergi ( Haacke 1975) . Minimum recorded hatchling SVL was 23.7 mm ( Haacke 1975).

Haacke (1969) observed P. garrulus calling during March at the Nosob Camp, Kgalagadi-Gemsbok National Park, South Africa, after a rainfall event, suggesting that rainfall may cause bouts of calling outside the normal breeding season. During the observed event, the geckos called throughout the night, rather than the normal calling period around sunset. A similar observation was made at the Aha Hills, Namibia (northern portion of the distribution), during early February (Predinger pers. com.). For further notes on natural history and behavioural ecology of P. garrulus , seesee Hibbitts and Whiting (2005), Hibbitts (2006), Hibbitts et al. (2007, 2012).