This species was named for the Latin 'dispar' meaning dissimilar or different.
Phrynobatrachus dispar is a miniature (snout–vent length < 25 mm) species of puddle frog endemic to Príncipe Island in the Gulf of Guinea. Members of this genus are identified by the presence of a midtarsal tubercle, elongate inner metatarsal tubercle, and outer metatarsal tubercle. Numerous prominent asperities are present on the dorsum, and contrasting coloration includes dark barring on the thigh and leg. Scapular glands are present, forming a broken X-shaped pattern. Tympanum is indistinct, measuring less than half the width of the eye. Ventrum is pale cream-colored and clear except for the throat and a few darkly pigmented spots extending along the flanks to just beyond the front legs and distinct dark brown bars lining the lower jaw. Undersides of the hind limbs are a clear, slight yellowish hue. Like all Phrynobatrachus species, P. dispar lacks manus webbing; pes webbing is absent or extremely rudimentary and distal phalanxes are T-shaped, resulting in the appearance of dilated toe tips (Uyeda, Drewes, and Zimkus, 2007).
The IUCN Red List (2009) categorizes this species as Least Concern, because although its Extent of Occurrence is much less than 5,000 km2, it is an adaptable species occurring human-modified habitats as well as in forest (Drewes, 2004).
This species is not known from any protected areas (Drewes, 2004).
This species is adaptable, facing no immediate threats (Drewes, 2004).
Populations of this species are stable (Drewes, 2004).
Phrynobatrachus dispar males have distinct white-tipped conical asperities and a clear, cream colored throat. Female P. dispar have numerous minute asperities on the flanks of the body, and ventral coloration varies from large, distinct brown blotches against a cream colored background to diffuse mottling of light brown spots. Distinct vertical barring is present on the thigh and leg (Uyeda, Drewes, and Zimkus, 2007).
Phylogenetic reconstruction utilizing the12S rRNA, valine-tRNA, and 16S rRNAgenes demonstrates monophyly of both Phrynobatrachus dispar from Príncipe (Uyeda, Drewes, and Zimkus, 2007). Sequence divergence within species was generally trivial compared to among-species divergences with inter-island pair-wise comparisons having a mean sequence divergence of 0.057 ± 0.002. Sequence divergence of Phrynobatrachus ranged from 0.001–0.005 (mean = 0.003 ± 0.001). Sequence data also demonstrate considerable divergence between Phrynobatrachus leveleve and P. dispar. Using a low estimate of divergence of 19% for the cytochrome b gene and a molecular clock estimate as high as 1.4% sequence divergence per million years, a value considerably higher than estimated divergence rates found in other amphibians (Caccone et al. 1997; Veith et al. 2003), suggests a time of divergence that predates the estimated origin for São Tomé of 13 million years ago (Lee et al. 1994).
Mitochodrial sequence data from the same mitochondrial 12S rRNA, valine-tRNA, and 16S rRNA , as well as combined sequence data from mitochondrial and nuclear (RAG-1) genes support a sister relationship between P. dispar and P. mababiensis A (Namibia), and in turn P. leveleve is sister to these two species (ZImkus et al, 2010).
Aquatic tadpoles are currently known but undescribed (R. Drewes, pers. comm.).
Phrynobatrachus dispar is morphologically most similar to other miniature species of puddle frogs, including P. leveleve, P. calcaratus, P. cornutus, P. inexpectatus, P. keniensis, P. kinangopensis, P. mababiensis, P. minutus, P. parvulus, and P. scheffleri. P. leveleve and dispar can be readily distinguished from each other in both sexes. Phrynobatrachus leveleve are distinguished from Phrynobatrachus dispar by a lower jaw distinctly marked with vertical banding, a darkened vocal sac, the presence of minute spicules arranged in a U-shaped pattern along the anterior margin of the jaw and a proportionally smaller eye. Males of P. dispar have distinct white-tipped conical asperities, whereas P. leveleve have fewer asperities, which are only faintly noticeable to the naked eye. Female P. leveleve are distinguished from female P. dispar by the absence of asperities in most individuals, smaller size and duller coloration. Female P. dispar (N=20, SVL=22.2 mm) are also significantly larger than P. leveleve (N=17, SVL=19.6 mm). Although highly polymorphic, the overall coloration of both male and female P. leveleve is duller, generally lacking distinct vertical barring on the thigh and leg as found in P. dispar. Phrynobatrachus dispar is distinguished from P. calcaratus and P. cornutus by the absence of an eyelid cornicle (although a small bump may be observed in the same location).
Dorsum coloration is quite striking, including dark barring on the thigh and leg, and numerous prominent asperities. Scapular glands are present, forming a broken X-shaped pattern. Phrynobatrachus dispar males have distinct white-tipped conical asperities and a clear, cream colored throat. Female P. dispar have numerous minute asperities on the flanks of the body, and ventral coloration varies from large, distinct brown blotches against a cream colored background to diffuse mottling of light brown spots. Distinct vertical barring is present on the thigh and leg (Uyeda, Drewes, and Zimkus, 2007).
Specimens measured by Uyeda et al. (2007) range in size from 13.5-18.1 mm (15.6 ± 1.3 mm), while females range from 17.8-24.7 mm (22.2 ± 1.9 mm).
Phrynobatrachus dispar is endemic to Príncipe Island (Democratic Republic of São Tomé and Príncipe) within the Gulf of Guinea.
Phrynobatrachus dispar is distributed from low to medium elevations (sea level- 948 m) on Príncipe Island. It is present in primary forest, farm bush (heavily degraded former forest), and abandoned plantations where wet conditions prevail. It is generally not present close to human habitation (Drewes, 2004).
This species is generally common where it occurs (Drewes, 2004).
This species breeds in most types of water but does not favor drainage ditches.