Litoria calliscelis ( Peters, 1874 )

Parkin, Tom, Rowley, Jodi J. L., Elliott-Tate, Jessica, Mahony, Michael J., Sumner, Joanna, Melville, Jane & Donnellan, Stephen C., 2024, Systematic assessment of the brown tree frog (Anura: Pelodryadidae: Litoria ewingii) reveals two endemic species in South Australia, Zootaxa 5406 (1), pp. 1-36 : 25-28

Litoria calliscelis ( Peters, 1874)

Suggested common name: South Australian Tree Frog

Figs 11 , 12

Hyla calliscelis . Peters, W.C.H. (1874) Über neue Amphibien ( Gymnopis, Siphonops, Polypedates, Rhacophorus , Hyla, Clyclodus, Euprepes, Clemmys ). Monatsberichte der Königlichen Preussische Akademie des Wissenschaften zu Berlin, 1874, 616–624.

Lectotype. ZMB 92805 (adult male), collected in the vicinity of Adelaide, South Australia, by Richard Moritz Schomburgk, natural historian, botanist, and curator of the Adelaide Botanic Gardens from 1865 until his death in 1891.

Synonyms.

Hyla inguinalis Ahl, 1935 . Holotype: ZMB 14080 , Type locality: “ Südaustralien (wahrscheinlich Umgebung von Adelaide)” = South Australia (probably around Adelaide). Ahl, E. (1935) Beschreibung eines neuen Laubfrosches aus Südaustralien. Zoologischer Anzeiger, 109, 252–253.

Material examined. Hyla inguinalis and H. calliscelis types examined from high-resolution images. For full list of specimens examined in morphometric analyses see Supplementary Table S1 (https://zenodo.org/ record/8423599).

Revised diagnosis. Litoria calliscelis is diagnosable from all other members of the L. ewingii group by a combination of (1) adult body size of 27–34 mm for males and 28–45 mm for females, (2) moderately robust build, (3) pads wider than fingers (mean Fin3W/Fin3 DW = 0.6) and toes (mean Toe4W/Toe4 DW = 0.7), (4) webbing on hands vestigial but relatively well-developed on the feet (extending to the 1 st subarticular tubercle on the 4 th toe [see Fig 8 , Type B]), (5) posterior edge of thigh yellow-orange, usually patterned with dark spots or blotches (n=10/11), occasionally plain (n=1/11), (6) usually a single dark spot present in the inguinal region, most often right at the junction of the thigh and body (n=7/11), sometimes 2–3 spots (n=1/11) or plain (n=3/11), (7) genetically by apomorphic nucleotide states at 10 sites in the ND4 gene ( Table 4 ). Diagnoses of Litoria calliscelis and the other species described herein are presented in Table 8 for ease of comparison.

Description of lectotype. We describe the lectotype based on images of the specimen after more than 148 years in preservative ( Fig. 11 ). Habitus moderately slender. Head slightly longer than wide, widest at commissure of the jaws. Tympanum oblong-shaped, smaller than eye, and partially obscured by a tympanic fold. Snout rounded in dorsal and lateral profiles. Fingers unwebbed and toes with moderate webbing. Finger and toe pads wider than digits. Sub-articular tubercles and metacarpal tubercles visible, inner-metatarsal tubercles prominent, oblong-shaped and approximately half the length of the fourth toe. Darkened nuptial pads present indicating specimen is an adult male. Legs relatively long and slender. Texture of dorsal surface smooth with minor scattered tubercles, ventral surface coarsely granular, inguinal region, lower surface of tibia, upper surface of thighs and throat smooth.

Colour in preservative. Dorsum light pinkish yellow with darker grey longitudinally bifurcated bands from between eyes to vent. Ventral surface creamy yellow. Broad grey facial mask extends from nare through eye to lateral zone, with cream stripe runs from below eye to shoulder. A distinct single dark spot present in the inguinal pocket, at the junction of the thigh and abdomen. Posterior edge of thigh coppery with numerous dark rounded spots.

Variation. Summary of variation in morphometric characters for each sex is presented in Table 6 .

Colour and pattern (in life). Variation in colour described from images taken in life ( Fig 12 ). Dorsum base colour varies from cream, grey, coppery to golden, with dark burnt brown longitudinally aligned and bifurcated (occasionally completely separated) bands extending from between eyes to vent. Upper surface of legs cream grey to coppery green or gold. Posterior edge of thigh yellow-orange, usually patterned with dark spots or blotches (n=10/11), occasionally plain (n=1/11). Distinctive golden patch on posterior edge of shoulder and armpit. Rosegold, pink to burnt-brown stripe runs from rostrum through eye and fades into the lateral zone. Pale to gold cream stripe runs from below eye to tympanum or shoulder. Iris copper-gold.

Advertisement Call. Call description is based on the calls of 59 individuals. The advertisement call of Litoria calliscelis has a duration of 1.57– 5.66 s (mean 3.35 s) comprising 7–32 pulsed notes (mean 16) with a short duration 0.09– 0.23 s (mean 0.16 s). Typically calls have the shortest note at the beginning (79.7%) with the longest note at the end (71.2%) ( Fig. 7 ). Amplitude rises and falls throughout the length of a note and the call but with no distinctive pattern. Dominant frequency ranges between 2063–2809 Hz (mean 2444 Hz).

Comparison with other species. Litoria calliscelis does not occur in sympatry with any other species in the Litoria ewingii Group making identification straightforward within its natural range. Where collection location is unknown though, Litoria calliscelis may be distinguished from L. ewingii by a thigh pattern usually comprising dark spots and blotches (versus typically plain in L. ewingii ) and somewhat reliably from L. sibilus by having an inguinal pattern consisting of a single dark spot in the inguinal pocket at the juncture of the thigh and abdomen (versus usually absent in L. sibilus , although faded spots are present in a small number of specimens (n=4/27).

Distribution and habitat. Endemic to the Southern Flinders ranges, Mount Lofty Ranges, Fleurieu Peninsula, Adelaide coastal Plain, and lower Murray River valley. Extends as far north as Port Augusta, with the eastern limit of its range bounded by the Murray River, extending from Lake Albert and Lake Alexandrina upstream to at least Blanchetown.Absent from the Yorke and Eyre Peninsulas, although three outlying observational records in the ALA dataset from Port Lincoln may require further validation.

Occurs in a variety of habitats including forests, heathlands and agricultural and suburban areas.

Ecology and reproduction. The species is recorded relatively commonly via FrogID (>1,600 records from 10 November 2017 – 30 June 2022), and is often heard calling in disturbed areas, with 39% of FrogID records of the species documented as being in urban habitats and 37% of records in rural areas. Males occur year-round in association with rainfall, with a distinct peak during June–October. Breeding occurs in static permanent and ephemeral waterbodies, such as dams, ponds, swamps, inundated ditches and streamside ponds and pools ( Anstis 2017; S. Scott pers. comm.). For a detailed description of tadpole development and morphology, see Anstis (2017).

Conservation status. AOO and EOO for Litoria calliscelis were calculated at 2852 km 2 and 37,649 km 2 respectively. Based on these calculations, a high relative abundance in FrogID submissions, and a lack of evidence for a population decline or obvious fragmentation, Litoria calliscelis likely qualifies for listing as Least Concern under the IUCN guidelines ( IUCN 2022).

Figures

FIGURE 7. Comparison of audio spectrograms of the advertisement calls of A) Litoria ewingii, Lake Burbary, Queenstown, Tasmania (FrogID: 166278) B) Litoria sibilus sp. nov., Pelican Lagoon, Kangaroo Island, South Australia (FrogID: 23471) and C) Litoria calliscelis, Victor Harbour, Fleurieu Peninsula, South Australia (FrogID: 242125).

FIGURE 8. Comparison of the hind feet of Litoria verreauxii and L. ewingii showing differences in toe pad size and webbing extent: Type A) Litoria verreauxii and Type B) represents Litoria ewingii, L. calliscelis and L. sibilus sp. nov. Subarticular tubercles 1 and 2 are indicated by circles.

FIGURE 11. Lectotype of Hyla calliscelis, ZMB 92805, adult male, Adelaide, South Australia. Images provided by Frank Tiller, Museum für Naturkunde, Berlin.

FIGURE 12. Images in life of Litoria calliscelis. A–C) unvouchered individuals from the Barossa Valley, South Australia (Ryan Francis); D–F) unvouchered individuals (Shawn Scott); D) Adelaide Hills Region, South Australia; E) Adelaide Hills Region, South Australia; F) Fleurieu Peninsula, South Australia.