Paedophryne amauensis, Eric N. Rittmeyer, Allen Allison, Michael C. Gründler, Derrick K. Thompson & Christopher C. Austin, 2012

Eric N. Rittmeyer, Allen Allison, Michael C. Gründler, Derrick K. Thompson & Christopher C. Austin, 2012, Ecological Guild Evolution and the Discovery of the World’s Smallest Vertebrate, PLoS ONE 7 (1), pp. 1-11 : 1-2

Paedophryne amauensis , sp. nov.

(urn:lsid:zoobank.org:act: 496 - F 26 AB-CD 82 - 4 A 9 C- 944 C-070 EC 86 ADAA 4) Etymology. The species epithet refers to the type locality, near Amau Village, Central Province, Papua New Guinea.

Holotype. LSUMZ 95000 (field tag CCA 5739 ), adult male, collected by C.C. Austin and E.N. Rittmeyer near Amau Village, Central Province, Papua New Guinea, 0 9.9824 °S, 148.5785 °E, 177 m, 7 August 2009 .

Paratypes. LSUMZ 95001 , same data as holotype, except collected 6 August 2009 ; LSUMZ 95002 , same data as holotype, except collected 10 August 2009 ; LSUMZ 95003 - 4, same data as holotype, except collected 12 August 2009 ; LSUMZ 95005 - 6, same data as holotype, except collected 14 August 2009 .

Diagnosis. A minute microhylid (male SVL = 7.0–8.0 mm) of the genus Paedophryne based on the following combination of characters: eleutherognathine jaw, 7 presacral vertebrae, first digits of hand and foot reduced to single elements, prepollex and prehallux reduced to single elements ( Fig. 1). Legs moderately long ( TL / SVL = 0.478–0.507), snout broad and short ( EN / SV = 0.075–0.084, EN / IN = 0.667–0.765), and eye relatively large ( EY / SVL = 0.127–0.150). Digits un-webbed with slightly enlarged discs (3 F / SVL = 0.025–0.033; 4 T / SVL = 0.036–0.050). First finger and first toe reduced to vestigial nubs, second and fourth fingers and second and fifth toes also markedly reduced. Dorsal coloration dark brown with irregular tan to rusty-brown blotches; lateral and ventral surfaces dark brown to slate grey with irregular bluish-white speckling. Detailed mensural characters and proportions provided in Table 1 and Table 2.

Paedophryne amanuensis is distinguished from all congeners by its smaller size ( SVL = 10.1–10.9 mm in P. kathismaphlox, 11.3 mm in P. oyatabu, 8.3–8.9 mm in P. swiftorum ) and longer legs ( TL / SVL = 0.35–0.39 in P. kathismaphlox, 0.40 in P. oyatabu, 0.427–0.471 in P. swiftorum ). Paedophryne amauensis is further distinguished from P. oyatabu and P. swiftorum by its longer, narrower head ( EN / SV = 0.062, EN / IN = 0.64 in P. oyatabu; EN / SV = 0.064–0.071, EN / IN = 0.579–0.632 in P. swiftorum ), and from P. kathismaphlox by its shorter, broader head ( EN / SV = 0.067–0.079; EN / IN = 0.78– 0.80 in P. kathismaphlox). The call of P. amauensis differs from that of P. swiftorum by its higher dominant frequency (7300 Hz in P. swiftorum ) and by consisting of single notes, rather than eight paired notes as in P. swiftorum . The calls of P. kathismaphlox and P. oyatabu are unknown.

Call. This species is crepuscular and calls from within leaf litter in primary forest at dawn and dusk. Its call consists of a continuous series of high-pitched notes with a dominant frequency of ~ 8400–9400 Hz. Individual notes range in duration from 2– 14 ms and are produced at a rate of 1.5 notes/s ( Fig. 2; Table 3). The overall acoustic impression is that of a stridulating insect. Individuals generally call from one to three minutes and then rest briefly before resuming. In a 5.5 minute recorded sequence, one individual ( NS 2, Table 3) produced a total of 355 calls in four groups, with the interval between groups ranging from 3.3 to 40.8 s.