Litoria lundeliusi, Tyler & Prideaux, 2016

Tyler, Michael J. & Prideaux, Gavin J., 2016, Early to middle Pleistocene occurrences of Litoria, Neobatrachus and Pseudophryne (Anura) from the Nullarbor Plain, Australia: first frogs from the “ frog-free zone ”, Memoirs of Museum Victoria 74, pp. 403-408 : 405

Litoria lundeliusi sp. nov.

Zoobank LSID. http://zoobank.org/ urn:lsid:zoobank.org:act:

2ECD98EC-4924-4E5D-83BC-A7CCBC098199.

Holotype. WAM 09.3 .264. An incomplete right ilium lacking the proximal portion of the acetabular fossa and the extreme superior margin of the superior acetabular expansion ( figs. 3A–B ).

Etymology. Named in honour of Ernest L. Lundelius, pioneer Quaternary vertebrate palaeontologist who initiated the first Nullarbor cave excavations in 1955 and 1964, before returning in 2009 to discover the first fossil frog specimen known from the region.

Type locality. The holotype originated from infill sedimentary unit 3 within the main chamber of Leaena’s Breath Cave, Nullarbor Plain, southeastern Western Australia ( fig. 1 ). Specifically, it was sieved from sediment excavated from LBC Pit A, quadrat 4, depth 65–70 cm in 2011 by a team led by GJP. Precise location data for the site are registered with the Department of Earth and Planetary Sciences, Western Australian Museum, Perth. Fine-grained sediments in unit 3 are of reversed magnetic polarity, which along with overall species composition of the assemblage, indicate an early Pleistocene age (Matuyama Reversed Chron) ( Prideaux et al., 2007). This falls within the Naracoortean land mammal age ( Megirian et al., 2010).

Diagnosis. Recognised as a species of Litoria due to presence of a well-developed pre-acetabular zone. Distinguished from other species on the following attributes. Anterior border is broad and evenly curved and terminates inferiorly parallel to the slightly raised acetabular rim. The dorsal prominence is broad and distinctly raised. It extends from a position above the middle of the acetabulum, distally to above the commencement of the preacetabular zone. There is no dorsal protuberance. The ilial shaft bears a short remnant of a very narrow flange curving medially and about 100 microns deep. The shaft depth is equivalent to approximately two thirds of the depth of the acetabular fossa.

Comparison with other species. The ilial characteristics of L. adelaidensis ( fig. 3C ) including the large acetabular fossa with a conspicuous peripheral rim, narrow dorsal prominence and reduced supra-acetabular zone, distinguish it from L. lundeliusi . The ilium of L. lundeliusi , which is presumed to be that of an adult given the very short nature of the subadult stage, is less than half the size of those of the other two southern species, L. cyclorhyncha and L. moorei . L. lundeliusi is distinguished from L. rubella sensu stricto ( fig. 3D ) by having a broader pre-acetabular zone, a deeper and more extensive acetabular fossa, a more extensive supra-acetabular region, and a curved and narrow ilial ridge, which may be extensive in complete specimens. L. lundeliusi also lacks a dorsal prominence. Future comparisons should be made, however, with L. rubella sensu lato, which is currently under taxonomic revision and will soon be divided into several species. This species complex is extensively distributed through Australia and southern New Guinea, and is renowned for its capacity to colonise diverse and, for a hylid, relatively arid habitats.

Figures

Figure 1. Map of Australia showing modern occurrence records extracted from the Atlas of Living Australia (www.ala.org.au) and location of Leaena’s Breath Cave (black triangle). a) Anura. b) Neobatrachus sudelli. Note that the two most northwestern records may represent N. aquilonius (J. D. Roberts, pers. comm., 27 June 2015). c) Pseudophryne guentheri (light green) and P. occidentalis (dark green). d) Litoria adelaidensis (red), L. cyclorhyncha (purple) and L. moorei (light brown).

Figure 3. Pleistocene frog ilia from Leaena’s Breath Cave (prefix WAM) compared with modern specimens (prefix SAMA). a) WAM 09.3.264. Right ilium of holotype of Litoria lundeliusi sp. nov. from Leaena’s Breath Cave (unit 3). b) WAM 09.3.264. Enlargement of acetabular region of holotype of Litoria lundeliusi sp. nov. c) SAMA R68398. Representative left ilium of Litoria adelaidensis. d) SAMA R68399. Representative right ilium of Litoria rubella sensu stricto. e–h) Representative ilia of Neobatrachus sudelli highlighting extreme divergence in the form of the dorsal prominence. e) WAM 09.3.265. f) WAM 09.3.261. g) WAM 09.3.269. h) WAM 09.3.273. i) Right ilium of Pseudophryne sp. indet.