Table 1.
Measurements in millimeters of selected type specimens, including types of new species described here.
Table 2.
Summary of snout vent length (SVL) in milimeters for African clawed frogs.
Table 3.
Summary of lateral line counts
Fig 1.
Mitochondrial DNA chronogram using calibration from [34].
New and resurrected species detailed here are indicated in red, possible additional new species are indicated with blue, and species with paraphyletic mtDNA are indicated with gray. Dots subtending nodes indicate posterior probabilities as indicated by the key with some values over terminal clades omitted for clarity. The scale is in units of millions of years.
Fig 2.
RAG1/ RAG2 chronogram using calibration from [34].
Labeling follows Fig 1 with the addition that tetraploid homeologs are indicated with α and β and, for octoploid and dodecaploids, each of these homeologs classes is further divided into two or three categories indicated by numbers. Homeologs of new and resurrected species are in red. Letters in circles indicate homeologous lineages inferred to be descended from six tetraploid ancestral species A–F. Data are lacking from X. petersii, X. poweri, and X. victorianus, which form a clade with X. laevis, and from X. fraseri.
Fig 3.
A summary phylogeny inferred by comparing the mitochondrial and autosomal gene trees depicted in Figs 1 and 2. New and resurrected species described here are in red. S, A, L, and M refer to subgenus Silurana, and the amieti, laevis, and muelleri species groups within subgenus Xenopus respectively. Dotted lines indicate paternal ancestral lineages. Circles over internal nodes indicate allopolyploidization events; shapes on branch tips indicate ploidy of extant species; colored next to these shapes circles indicate call type inferred from this study and Tobias et al. [42]. Letters over red dots refer to ancestors whose homeologous lineages are labled in Fig 2. Daggers indicate lost ancestors, including up to three diploid species (assuming allotetraploidization in subgenus Xenopus) and at least three tetraploid ancestors (A, B, and C).
Fig 4.
External morphology of subgenera Silurana and Xenopus.
Comparison of external morphology of subgenera Xenopus (right, specimen of X. victorianus CAS 250836 [DCB-202]) and Silurana (left, X. calcaratus CAS 207759) including in Silurana rougher skin, relatively smaller eyes, relatively shorter subocular tentacle (in comparison to sympatric Xenopus species), and relatively less of eye covered by lower eyelid (top), relatively shorter feet (middle), and ventrally fused cloacal lobes, claw on prehallux, and lack of skin ridge on first pedal digit from the prehallus (bottom).
Fig 5.
Internal morphology of subgenera Silurana and Xenopus.
Comparison of osteology of subgenera Xenopus (left, holotype specimen of Xenopus amieti, MHNG 2030.80 and Silurana (right, X. calcaratus, CAS 207759). Differences include (a) paired nasal bones in subgenus Silurana but not subgenus Xenopus, (b) absence of the vomer bones in the palate of subgenus Silurana but not subgenus Xenopus and (c) fusion of the first two presacral vertebrae in subgenus Silurana but not subgenus Xenopus.
Fig 6.
Pictures of type specimens of resurrected and new species including X. calcaratus ZMB 8255A (lectotype), X. mellotropicalis NCSM 76797 (holotype), X. allofraseri CAS 207765 (holotype), X. eysoole MCZ A-138016 (holotype), X. kobeli MCZ A-148037 (holotype), X. parafraseri MCZ A-148034 (holotype), and X. fischbergi CAS 255060 (holotype). Scale bar is 5 mm. This is a truncated version of Fig 6 and is meant for preview purposes. Please refer to S3–S5 Figs in the Supporting information for the full size version.
Fig 7.
Pictures of resurrected and new species in life. This is a truncated version of Fig 7 and is meant for preview purposes. Please refer to S6–S8 Figs in the Supporting information for the full size version.
Fig 8.
The male vocalizations of resurrected and new species.
Axes are labeled only in panel A. For some of the recorded individuals, specimen IDs are available including X. kobeli (field ID: BJE 3073), X. allofraseri (MCZ A-148176), X. parafraseri (CAS 249961), X. eysoole (MCZ A-148129 or MCZ A-148130), and X. calcaratus (field ID: VG09-368 or VG09-369).
Table 4.
Vocal characteristics of the male advertisement call of new species of African clawed frog.
Fig 9.
Karyotypes of new and resurrected species.
(A) X. calcaratus, NMP6V 74746 (VG05-S; female) from Cameroon, (B) X. mellotropicalis, CAS 255058 (BJE 3652) from Republic of Congo, (C) X. fischbergi non-vouchered sample (BJE 3873), (D) X. parafraseri, CAS 249961 (BJE 3060) from Cameroon, (E) X. allofraseri, MCZ A-148162 (BJE 3486) from Bioko Island, Equatorial Guinea, (F) X. kobeli, MCZ A-148038 (BJE 3076) from Cameroon, (G) X. eysoole, MCZ A-148097 (BJE 3220), from Cameroon.
Fig 10.
Type localities with black dots inside symbols. For X. fischbergi white circles with slashes indicate specimens from which we have genetic data (including the holotype), unfilled circles are specimens from Tinsley et al. [1] and those other collections from which we lack genetic data, including one field sample from Uganda–indicated by a hexagon–in which the X. fischbergi-specific parasite Protopolystoma occidentalis was detected (J. A. Jackson & RCT, unpublished).
Fig 11.
MicroCT scans of skulls of two tetraploids in subgenus Silurana and two dodecaploid in subgenus Xenopus.
Dorsal view is on the left and ventral view is on the right, including the lectotype specimen of Xenopus (Silurana) calcaratus (ZMB 8255A) from Cameroon and a specimen from Bioko Island (CAS 207759), holotype of X. (S.) mellotropicalis (NCSM 76797), and the holotypes of the new dodecaploid species from subgenus Xenopus: X. eysoole (MCZ A-138016) and X. kobeli (MCZ A-148037). The type specimen of X. calcaratus was preserved with its mouth ajar.
Fig 12.
MicroCT scans of skulls of four tetraploids in subgenus Xenopus.
Images are of a type specimen of X. fraseri (BMNH 1947.2.24.79) and holotypes of the new tetraploid species from subgenus Xenopus: X. fischbergi (CAS 255060), X. allofraseri (CAS 207765), X. parafraseri (MCZ A-148034). Each ventral view (on right for each species) and insert shows the presence of vomerine teeth (X. fraseri and X. fischbergi) or absence of vomerine teeth (X. allofraseri and X. parafraseri).