Anstisia, Webster & Bool, 2022

Webster, Grant N. & Bool, Ian, 2022, A new genus for four myobatrachid frogs from the South Western Australian Ecoregion, Zootaxa 5154 (2), pp. 127-151 : 144-145

Anstisia new genus

Anstisia . Type species: Crinia rosea, Harrison, 1927 .

Definition. Nidicolous life history, terrestrial endotrophic larvae with vestigial non-feeding mouthparts, larvae <20 mm in maximum length, adults <25 mm in maximum length, fourth toe length <7 mm, testes mass <0.001 g, egg compliment <50, monophasic call, primarily spring breeding.

Content. Four species: Anstisia alba (Wardell-Johnson & Roberts) , lutea (Main) , rosea (Harrison) , and vitellina (Wardell-Johnson & Roberts) .

Distribution. Endemic to south-western Western Australia.

Etymology. The generic name Anstisia honours the extensive life work of Dr Marion Anstis, work that has concisely outlined the developmental differences of the three current and four former Geocrinia species, allowing for delineation between the two genera. Relevantly, given that her work has largely focused on the life histories of Australian anurans, in our opinion it is fitting that her name be applied to a genus that is distinguished largely on its unique life history strategy and larval morphology.

Diagnosis. The appearance in life of frog species within Anstisia and Geocrinia is similar (see Figures 6 and 7 ) although key differences exist. The three species of Geocrinia can be reliably distinguished from the four Anstisia species by ventral surface patterning in most cases. Ventral surfaces of G. laevis and G. victoriana always have some degree of marbling in the form of light grey or brown blotches. This patterning can at times be present in G. leai , but this species can also present a uniform ventral surface with pale yellow hues. Males of all three species can feature yellow throats. All Anstisia species however have distinctly individual ventral colouring. The ventral surface of A. alba is entirely uniform white; almost entirely coloured anteriorly with yolk orange in A. vitellina ; rose with pink to orange hues in A. rosea ; and off-white or cream usually with a dark yellow or lemon-yellow wash in A. lutea . Males of the latter two species are known to have dark grey or black throats, with females having pink and yellow throats respectively. Dorsally, Geocrinia species are highly variable but frequently feature a broad darker central marking. The dorsal pattern of A. rosea and A. lutea can resemble that of Geocrinia but these species are reliably less variable, with the dorsal marking forming an inverted “V” on the lower back. Both A. alba and A. vitellina are similar in dorsal appearance with broken streaks of scattered darker spots.

In life, the appearance of tadpoles differs noticeably and cannot be confused, as Geocrinia tadpoles have a kertinised oral disc with feeding mouthparts, while Anstisia tadpoles do not. Tadpoles of the three Geocrinia species are uniformly brown on the dorsum, with patchy lighter colouration on the sides of the body and venter. In G. laevis and G. victoriana the tail muscle is very light brown and fins mostly clear, while the tail muscle in G. leai is pigmented with dark and light blotches with some irregular markings across the fins. Tadpoles of all Anstisia species possess vibrant light blue flecks across the body and tail, which are most apparent when viewed laterally, against a pigmentation of deep red-brown ( A. alba / A. vitellina ) to dark yellow-brown ( A. lutea / A. rosea ). In the Anstisia species, this pigmentation is lighter on the tail muscle than body, and fins are opaque. Metamorph frogs of both genera resemble the adults, although Anstisia species possess the vibrant blue flecking typical of the tadpoles.

In terms of distinguishing the two genera by advertisement call, Geocrinia species can be identified by a call consisting of two distinct note types (biphasic), compared to a singular note type (monophasic) in Anstisia . The introductory note alone, present in Geocrinia , is sufficient to distinguish this genus from all Anstisia species. The closely related genus, Assa , shares a similar monophasic ticking call to Anstisia ; however these genera are entirely allopatric, with Assa occurring in northern New South Wales and southern Queensland.

Figures

FIGURE 6. The species of Geocrinia Blake 1973 in life.A) G. laevis, from Cradle Mountain, Tasmania; B) G. victoriana, from Eden, New South Wales; and C) G. leai, from Pemberton, Western Australia. Photographs by G. Webster.

FIGURE 7. The species of Anstisia gen. nov. in life. A) A. rosea, from Pemberton, Western Australia; B) A. lutea, from Walpole, Western Australia; C) A. alba, from Witchcliffe, Western Australia; and D) A. vitellina, from Spearwood Creek, Western Australia. Photographs by G. Webster.