Eric N. Rittmeyer; Allen Allison; Michael C. Gründler; Derrick K. Thompson; Christopher C. Austin

“ This pattern may suggest developmental truncation as a mechanism for the extremely reduced body size of Paedophryne, as has been proposed for other miniaturized anurans [10] ; however, little is known of the cranial ontogeny in direct-developing anurans. Direct development has evolved numerous times independently and cranial ontogeny has only been examined in detail in a small number of species. These examined species show varied sequences of ossification. ”

“ These direct developing species belong to clades that include much larger direct developing species, thus direct development may facilitate the evolution of extreme miniaturization in frogs [8] . Miniaturized species also typically express a generally reduced and simplified morphology [7] , [9] , [10] . These changes are also apparent in Paedophryne, which exhibit a reduced number of presacral vertebrae, reduced ossification of several cranial elements, and phalangeal and digital reduction on both the hand and foot (Fig. 1) . ”

“ All but two species of extremely miniaturized frogs inhabit tropical wet-forest leaf litter; the two exceptions (Choerophryne burtoni, Oreophryne minuta) inhabit dense moist moss. Frogs are sensitive to water loss [38] [39] [40] and small species, which have a high surface to volume ratio, are particularly susceptible to desiccation [41] . Indeed, one of smallest known amniote species (Sphaerodactylus parthenopion) loses water at much higher relative rates than larger congeners, and is known to select moist microhabitats to compensate [41] . ”

“ This distribution of miniaturization among frog families suggests that the evolution of miniaturization has been nonrandom with respect to phylogeny.
Table 5 "Sizes and mode of reproduction in extremely miniaturized frogs. (10.1371/journal.pone.0029797.t005) "File:Pone.0029797.t005 Sizes and mode of reproduction of the 29 smallest frog species (i.e. those with a maximum male size <13 mm) , arranged by maximum male size, or, if unavailable, mean male size or female size. All values in millimeters (mm) . Species described herein are in bold. ”

“ 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) . ”

“ The call generally consists of four double notes (Fig. 2; Table 4) delivered in a continuous series at the rate of 0.66 calls/s. Each note is around 7 ms in duration and the entire call lasts approximately 0.5 seconds. ”

“ Asterisks (*) indicate bootstrap support of 100 or posterior probability of 1.0. B. Full phylogeny of asterophryine frogs continued from Figure S1A. (TIF)
File:Pone.0029797.s001.tifClick here for additional data file. Table S1 Samples included in molecular phylogenetic analyses. Specimens and Genbank accession numbers for samples used in phylogenetic analyses. Bolded lettering indicates sequences collected for this study. (PDF) (data file pone.0029797.s002.pdf) We thank the local people from Papua New Guinea for the privilege to conduct fieldwork on their land. ”

“ Osteological characters of Paedophryne amauensis, P. swiftorum.A. X-ray of paratype of Paedophryne amauensis (LSUMZ 95002) . B. X-ray of paratype of P. swiftorum (BPBM 31886) . C,E,G,I. Photos of cleared and double-stained paratype of P. amauensis (LSUMZ 95002) . C. Whole body. E. Head. G. Hand. I. Foot. D,F,H,J. Photos of cleared and double-stained paratype of P. swiftorum (BPBM 31886) . D. Whole body. F. Head. H. Hand. J. Foot. ”

“ Chenna, R & McGettigan, PA (2007) , “Clustal W and Clustal X version 2.0.”, Bioinformatics 23: 2947–2948, 17846036, pmid:17846036 ↑ Posada, D (2008) , “jModelTest: phylogenetic model averaging.”, Molecular Biology and Evolution 25: 1253–1256, 18397919, pmid:18397919 ↑ Zwickl, DJ (2006) , Genetic algorithm approaches for the phylogenetic analysis of large biological sequence datasets under the maximum likelihood criterion: The University of Texas at Austin. ”