Taxonomic notes on the Asian frogs of the tribe Paini (Ranidae, Dicroglossinae): 1. Morphology and synonymy of Chaparana aenea (Smith, 1922), with proposal of a new statistical method for testing homogeneity of small samples

Abstract

The species from northern Vietnam described as Rana fansipani Bourret, 1939 is shown to be a synonym of the species from northern Thailand described as Rana aenea Smith, 1922. The male secondary sex characters of this species are described in detail for the first time. Combined with a few other characters, they allow this species to be distinguished from the closely related Rana unculuanus Liu, Hu and Yang, 1960 from southern China. Both species should be placed in a subgenus Chaparana (Chaparana), a member of the tribe Paini of the subfamily Dicroglossinae of the Ranidae. In this study, we propose a new statistical method for testing homogeneity of small samples: this consists of considering the values obtained for each specimen and for each regression factor score as morphometric characteristics of this specimen within the frame of this analysis; these values, or some of them, can be used to compare subgroups of specimens by non‐parametric tests such as the Mann–Whitney U test.

Keywords:

• Anura
• Chaparana
• Chaparana aenea
• Chaparana fansipani
• Chaparana unculuanus
• China
• Dicroglossinae
• male secondary sex characters
• Paini
• Ranidae
• statistical method
• Thailand
• Vietnam

Acknowledgements

We are very grateful to the following colleagues, without the help of whom this study would not have been possible: Steven Swan, Andrew Tordoff and other members of the Frontier field staff (Hanoi, Vietnam), for collecting on Fan Si Pan the two crucial adult breeding males of the species and presenting them to us for study; Jarujin Nabhitabhata (Bangkok, Thailand) for depositing in the MNHN collection three specimens of this species recently collected in Thailand; Nick Arnold and Barry Clarke (London, UK) for allowing us to examine specimens in their care in the BMNH collection; Fei Liang and Ye Changyuan (Chengdu, Sichuan, China) for doing the same in the CIB collection. Thierry Deuve once again provided us with very useful specimens from Asian mountains.

Notes

Juv., juvenile (as defined in Dubois 1976, p 31–33); nm, measurement not taken on this specimen.

Of the 36 measurements, only 32 are available for all 13 specimens and were used for the principal component analysis of Figure 5 and Table III.

Criteria of construction of subsamples: (G) geographic origin: Thailand (G1) versus Vietnam + China (G2); (S) sex: males (S1) versus females (S2); (D) ontogenetic stage: juveniles (D1) versus adults (D2). The sex of two juveniles is unknown, hence the total sample of 11 instead of 13 for the criterion “sex”. For each criterion of comparison, minimum and maximum values of RFS given for subsamples are those obtained by PCA for the first (RFS 1), second (RFS 2) and third (RFS 3) regression factor scores.

Significance levels before Bonferroni correction (BBC): ns, not significant, P>0.05; *P⩽0.05; significance levels after Bonferroni correction (ABC): ns, not significant, P>0.0167; *P⩽0.0167.

Ad., adult (as defined in Dubois 1976, p 31–33); nm, measurement not taken on this specimen.

Of the 36 measurements, only 27 are available for all six specimens and were used for the principal component analysis of Figure 6 and Table V.

For each criterion of comparison, minimum and maximum values of RFS given for samples are those obtained by PCA for the first (RFS 1), second (RFS 2) and third (RFS 3) regression factor scores.

Significance levels: ns, not significant, P>0.05; *P⩽0.05.