Crinia flindersensis, Donnellan & Anstis & Price & Wheaton, 2012

Donnellan, S., Anstis, M., Price, L. & Wheaton, L., 2012, A new species of Crinia (Anura: Myobatrachidae) from the Flinders Ranges, South Australia, Zootaxa 3499, pp. 1-26 : 17-22

Crinia flindersensis sp. nov.

Northern Flinders Ranges froglet

Figures 6, 9, 10, 12

Holotype. SAMA R 62991, an adult male collected at Bunyeroo Gorge , Flinders Ranges, Australia (31°25’04”S; 138°33’45”E) on 1 August 2007 by L. Price, S. Donnellan and R. Foster.

Other material examined. See Appendix 1.

Diagnosis. Crinia flindersensis sp. nov. is placed in Crinia by virtue of its molecular genetic phylogenetic placement within the genus and its close adult morphological affinity with C. riparia . Adults differ from C. signifera and C. parinsignifera in the incomplete expression of the back pattern polymorphism, particularly the absence of the ridged morph. Further differs from C. signifera in that it has a smooth palm, lacks a tarsal fold, and has reduced pigmentation on the throat of breeding males (vs palm markedly tuberculate and tarsal fold well developed in C. signifera ). Further differs from C. parinsignifera in that it has a coarsely mottled ventral pattern with black patches on a white background vs venter finely stippled with dark grey on a white background in C. parinsignifera . Not readily distinguished from C. riparia on adult external morphology but distinguished by reciprocal monophyly of mitochondrial DNA sequences, fixed allelic difference at the nuclear RAG1 locus and in the relative size of the larval oral disc, the length of the P 1 and P 3 larval tooth rows, and the frequency of occurrence of submarginal papillae on the larval oral disc.

Description of holotype. Small body size (19.6 mm SVL). Snout short and slightly pointed and equal in length to eye; canthus rostralis rounded; loreal region oblique. Tympanum indistinct, lightly tubercular and the same colour as dorsum. Toes and fingers long and without webbing. Finger length: 3>4>2=1. Toe length: 5>3>4>2>1. Outer metatarsal tubercles very small, palmar and plantar tuberlcules absent. Mild tubercles under fingers, weaker tubercules under toes. Dorsal skin mildly tubercular (in comparison with ventral surfaces), limbs smooth. Throat forearms, and abdomen strongly tubercular whereas ventral surfaces of lower forelimbs and entire hindlimbs smooth.

Colour in preservative. Ventral surface of thighs transparent (muscles visible through skin), throat, forelimbs and lower hindlimbs lightly pigmented with light brown ( Fig. 12). Abdomen cream and strongly marked with more than 20 irregularly-shaped dark grey spots and patches. Sharp transition in cream colour of abdomen to dark grey flanks along ventral margin of flanks. Dorsum uniform, dark grey without markings. Dorsal surfaces of forelimbs lighter colour than dorsum but with a few dark grey lateral marks on forearms and digits. Hindlimbs lighter grey than dorsum with a few dark grey lateral marks most prominent on toes. Snout black, but lips light brown.

Variation. Variation in morphometric traits is summarised in Table 2. In a sample of 49 preserved individuals from across the species range, the proportion of individuals with a ‘lyrate’ dorsal pattern was 43%, with an ‘intermediate’ pattern 14% and with the ‘smooth’ pattern 26% (16% of specimens were too faded to determine the back pattern). Variation in dorsal pattern in live individuals is illustrated in Fig. 9.

Ventral patterns vary considerably, with variation within locations being equivalent to that occurring across the entire range of the species (contrast Fig. 10C–H with Fig. 11). The abdomen has a white background with highly contrasting black marks and patches sometimes forming networks, continuing onto the thighs and lower throat in a few individuals.

Mating call structure. Call data are not available at present.

Larval morphology. Larvae at Gosner stages 30–38 from Bunyeroo Gorge (n=23) and at stages 28–30 from Warren Gorge (n=5) are described. Maximum length 35 mm, with a body length of 12.0 mm (stage 42, Bunyeroo Gorge). The tail is slightly less than twice length of body ( Table 3). Body small, oval and slightly streamlined, slightly wider than deep across abdomen. Snout rounded in dorsal view and in profile. Eyes dorsolateral. Iris mostly golden, gold ring around pupil and a V-shaped projection (umbraculum) in centre of dorsal edge. Nares small, moderately spaced, and open dorsally with a small raised flap on inside rim. Spiracle just visible from above, tapers slightly and opens dorsoposteriorly below horizontal body axis, posterior to midpoint. Vent tube dextral, short and narrow, opens midway up ventral fin and mostly unattached to fin behind.

Colour of dorsum and sides of body variable (Bunyeroo Gorge), from dense bright gold to dark golden-brown, reddish-brown or black, with diffuse, slightly darker markings in some and a small darker patch over base of body in most. Larvae from Warren Gorge were generally darker brown or rusty-brown to black, with a small darker patch over base of body. Body wall around sides of head transparent in earlier stages, increasingly pigmented as larva grows. By stage 41, hind limbs are banded; diffuse darker markings of adult visible and small tubercles present in some. Venter gradually becomes covered with bright copper-gold clusters increasing to dense, mostly opaque layer by stage 34 (Bunyeroo Gorge), clearer below mouth.

Larvae are known to metamorphose in the field in spring (November), but likely to do so from early spring to early summer. Metamorphs are miniatures of adults with variable dorsal patterns. The belly is translucent dark grey with finely scattered white-tipped granulation. Mean SVL of three metamorphs is 8.5 mm (8.0–9.0).

Key differences between larvae of the three species of Crinia from the Flinders Ranges are summarised in Table 4. C . flindersensis sp. nov. larvae differ from C. riparia in their more oval, often slightly plump body shape with a less elongate snout and slightly more arched fins. They also have a slightly shorter tail relative to body length than C. riparia (see Figs 6,7). Their narrower oral disc with its shorter P 1 and P 3 tooth rows, absence of submarginal papillae (or only very few in some) and narrower posterior medial gap in papillae, suggest the oral disc is likely to be less suctorial than the larger disc of C. riparia with its numerous papillae and very long tooth rows. The two also can differ in ventral pigmentation, which in fully grown C. riparia is transparent dark grey (Alligator Gorge) or with a dull copper sheen (Horrock’s Pass), and in C. flindersensis sp. nov. is bright opaque copper-gold (Bunyeroo Gorge) or with a dull copper sheen (Warren Gorge). Apart from pigmentation, the above differences suggest C. flindersensis sp. nov. is slightly less adapted to flowing water than occurs in C. riparia habitat. Crinia flindersensis sp. nov. (Bunyeroo Gorge) is more similar in body shape to C. signifera , which also has a more oval, plump body with slightly more arched fins than C. riparia and similar variable pigmentation, but C. signifera has a narrower oral disc than C. flindersensis sp. nov. with a much shorter P 3 row and narrower posterior medial gap in the papillae ( Table 4).

Habitat. A detailed analysis of the habitat of C. flindersensis sp. nov. (as “northern allopatry of R. riparia ”) is presented in Odendaal and Bull (1982) and is summarised here. Crinia flindersensis sp. nov. occupies rocky creeks with wide beds that generally lack live vegetation in the creek bed or along the banks. These creeks are generally steeper than those occupied by C. signifera but not as steep as those occupied by C. riparia in the southern Flinders Ranges. The majority of these creeks are shallow, have intermittent flows and are subject to flooding. The creek in Bunyeroo Gorge where larvae were collected, however, did not have steep sides, and had intermittent rocky patches and shallow, slowly flowing pools with scattered clumps of emergent thin-leaved sedges, mainly near the edges of pools.

Larvae are mainly bottom-dwellers, hiding among rocks and leaf litter. They often rest on rocks or sand in creek pools and appear to graze mainly algae and sediments in still or slowly flowing sections, retreating undercover if disturbed. Eggs were found adhering to the undersurfaces of submerged rocks in Bunyeroo Creek and Warren Gorge in a similar manner to C. riparia . Crinia signifera has quite a different mode of egg deposition, attaching eggs singly or in small clusters to vegetation or twigs in still or slowly flowing pools.

Distribution. The northern Finders Ranges from Black Springs, Wilkatana Station in the south to Billy Springs in the northern most foothills.

Etymology. Named for the Flinders Ranges, the mountain ranges in central South Australia to which the distribution of the new species is confined.