Rana vertebralis Hewitt 1927

Identification of Rana vertebralis Hewitt, 1927 The two river frogs in question can be easily distinguished on the extensive webbing reaching the last phalanx of the fourth toe in the Maluti River Frog, but with up to three phalanges free in the Phofung River Frog, and small tympanum, less than the eye-tympanum distance in the Maluti River Frog, larger in the Phofung River Frog. The description (Hewitt 1927) is brief and incomplete, with an important error. Only four statements are diagnostic, and all four identify the Maluti River Frog���Tympanum width less than eye-tympanum distance; toes completely webbed in five types (the description refers to half-webbed toes, but examination of the holotype PEM A 1550, and the paratypes PEM A 1551, A 1552, A 1562 and A 10562 shows this to be in error, only PEM A 1555 has webbing that does not reach the tip of the fourth toe). Hewitt (1927) illustrates the type in Plate 24. The quality of the reproduction is too poor to make out useful features. The left foot of the type appears to show that three phalanges of the fourth toe are free of webbing (Fig. 3 A). This would identify the type as a Phofung River Frog, in contradiction to the small tympanum. Unfortunately the type is now in very poor condition, but it clearly shows the fourth toe to be completely webbed. It appears that Fig. 2 of Plate 24 of Hewitt (1927) was retouched, as the dark line along the margin of the webbing is not present in the type (Fig. 3 B). The webbing might have been invisible in the photograph if this retouching had not been done. Whoever did it, however, got it wrong. It also appears that Hewitt's photograph was flipped horizontally, as the right foot and right hand of the type show the same orientation as the left foot and left arm in the photograph (Fig. 3). The same specimen was illustrated by Tarrant et al. (2008: Fig. 2 A) to show the poor condition. Note that the Tarrant et al. Fig. 2 A is flipped horizontally.
Published as part of Channing, Alan, 2015, The Maluti Mystery revisited: Taxonomy of African River Frogs (Pyxicephalidae, Amietia) on the Drakensberg Mountains in southern Africa, pp. 271-280 in Zootaxa 3925 (2) on page 276, DOI: 10.11646/zootaxa.3925.2.8, http://zenodo.org/record/236789
{"references":["Hewitt, J. (1927) Further descriptions of reptiles and batrachians from South Africa. Records of the Albany Museum, 3, 371 - 415, plates XX - XXIV.","Holotype PEM A 1550 Mont-aux-Sources","Tarrant, J., Cunningham, M. J. & Du Preez, L. H. (2008) Maluti Mystery: A systematic review of Amietia vertebralis (Hewitt, 1927) and Strongylopus hymenopus (Boulenger, 1920) (Anura: Pyxicephalidae). Zootaxa, 1962, 33 - 48."]}