Litoria mystacina ( Keferstein, 1867 )

Litoria mystacina ( Keferstein, 1867) View in CoL , nomen dubium

Fig. 10 View FIGURE 10

Holotype. ZMFK 28810 (ex Zoologischen Museums Göttingen ( ZMG) specimen ZMG 102e ), collected in 1864 by Bernhard Rudolf Schütte with the locality described as “ Australien ” ( Fig. 10 View FIGURE 10 ).

Measurements (mm) of holotype. SUL 33.7, FOL 19.8, TIB 13.2, FEL 12.3, LAL 6.1, UAL 4.8, HDW 9.8, DFE 6.0, IOD 3.9, IND 1.8, HDL 8.8, HD 4.9, SNT 4.3, EN 3.2, NS 0.8, EYE 2.6, TEY 1.0, TMP 2.1, 3TL 8.2, 3FDW 1.6, 3FW 0.9, PL 10.1, 4TDW 1.3, 4TW 1.2, IMT 1.5.

Remarks. This species was described from a specimen (originally Zoologischen Museums Göttingen 102e, subsequently transferred to the Zoologisches Forschungsmuseum Alexander Koenig, where it is ZMFK 28810) with the given locality “ Australien ”. The species was first placed in the synonymy of Litoria freycineti by Boulenger (1882), a synonymy repeated by Nieden (1923), Copland (1957) and Böhme & Bischoff (1984). Moore (1961), based on the characters noted in the description, expressed doubt on this synonymy and recommended that the type be re-examined. This was done by Cogger et al. (1983), who placed the name in the synonymy of L. rubella , a synonymy repeated by Böhme (2014). Böhme (2010) was unwilling to assign it to either, and merely listed the current status of the name as L. mystacina .

We have examined the holotype and agree that it is a member of the L. rubella species group, which also includes the L. dentata species complex. However, the specimen is faded, soft, and based on the lack of any trace of nuptial pads, a female. Because of the poor pigmentation of the specimen and the soft state of preservation making precise measurements difficult, we are unable to confidently place it with any particular species or population within the L. rubella species group in the absence of a specific collection locality. Identification of the specimen as L. rubella sensu lato is uncertain based on the known movements of the collector, Dr. Bernhard Rudolf Schütte. Schütte was in Australia for two periods. In the first, between 1859 and 1862, he arrived in Adelaide, and left from Sydney, and was in Sydney by 1861. At this time, he had qualifications in pharmacy and presumably worked as a pharmacist. On his return to Germany, he completed his medical degree, and returned to Australia in 1867 to practice medicine, departing permanently in 1884 ( Rowley et al. 2021; Parkin et al. 2024). The holotype has a nominal date of 1864, after Schütte’s return to Germany between his periods in Australia, and this is likely a date of donation rather than a year of collection.

Schütte’s frog collections with donation dates between 1862 and 1864 are covered by Keferstein’s (1867) paper, while his collections from the second visit are covered by Keferstein (1868). As noted by Parkin et al. (2024), most of the 1862–64 collections are of reptiles and amphibians that are nominally from the Sydney area or are of species that occur in the Sydney region. A few are south-western Australian specimens, and the small residue includes a few large or showy species that could have been obtained from natural history dealers in Sydney. The single small specimen of Hyla mystacina is not the sort of specimen that would likely be on offer from a commercial natural history dealer, and hence the likely source of the specimen is limited to south-western Australia or the Sydney region. There is a slight possibility that Schütte could have collected it from the Adelaide region shortly after arriving in Australia – we know nothing about his movements in this first part of his first visit. However, no member of L. rubella species complex occurs in southwestern Australia, in the Sydney region, or close to Adelaide.

It is possible that the type represents instead a member of the L. dentata species complex, of which L. quiritatus occurs in the Sydney region. Against this possibility, however, is the original description of coloration by Keferstein (1867): “Rückenseite ganz glatt, einförmig braunlich, Seiten des Kopfes von Schnauzenspitze bis zum Auge dunkel, Bauchseite warzig, einförmig hell” (Dorsal side completely smooth, uniformly brownish, sides of head from tip of snout to eye dark, belly side warty, uniformly light), and the fact that the 1864 collection reported on by Keferstein (1867) contains a separate series of specimens of the L. dentata species complex (ZFMK 28826–37) from Sydney, which were listed by Keferstein as Hyla rubella . These latter specimens bore a manuscript name Hyla nigrogularis , provided by Gerard Krefft of the Australian Museum, who also donated specimens to Keferstein and assisted with the transport of some of Schütte’s collections to Germany. We consider it unlikely that Keferstein (1867) would have identified specimens of a single population of a species as two different taxa in a single paper. Determination of the identity of the holotype of Hyla mystacina with a specific taxon in the L. rubella species group is only likely to be possible with forensic DNA sequencing technology, which we are not yet in a position to undertake, and consequently, we treat the name as a nomen dubium, with the possibility that future work may result in the name supplanting one of the other named taxa in the species group.