Ts just beyond the lower jaw, though species vary in the degree to which the rostrum is blunt or pointed. The canthus rostralis is typically flat to weakly concave, the loreal region is generally flat, and the internarial region varies from flat to weakly concave. All species lack a tongue and have a single Lurbinectedin chemical information opening to the Eustachian tubes. The floor of the mouth is typically wrinkled and covered in small pustules. The posteroventrally directed choanae are large, rounded, and largely or entirely visible in ventral view. Premaxillary and maxillary teeth jasp.12117 are present, but vomerine teeth are nearly always absent. The nares are prominent ellipsoid slits directed dorsally; a small sheet of skin projects from the margins of each naris, the extent and morphology of which varies among species but often features a laterally projecting nubbin. The size of the eye relative to the head varies among species as does the extent to which the eye is covered by the lower eyelid. In preservative, the pupil is typically round. Each eye is encircled by lateral-line plaques located on a raised ring of skin, though the degree to which this ring is observable varies based on specimen preservation. A subocular tentacle extends from the lateral margin of each eye; the length of this tentacle varies among species and is absent in two species (X. gilli and X. largeni). All species lack an externally visible tympanic annulus. The skin is generally PD325901 site smooth, although it can be covered by small spicules (especially those in the subgenus Silurana). A prominent feature of all adult Xenopus is the lateral-line system; the individual plaques (each comprising multiple sensory organs) resemble purchase Oxaliplatin stitches. Distinct lateral-line rows extend across the skin of the head and dorsal, lateral, and ventral body. In both males and females, the medial surfaces of the manual digits are covered by small black punctiform spicules. In males, these are accentuated into nuptial pads comprising sheets of darkly pigmented spicules on the manual digits as well as on the upper arm, forearm, and sometimes axillary region. The forelimbs are typically moderately robust and have elongate manual digits that lack webbing (in contrast to other African pipids, the dwarf clawed frogs Hymenochirus and Pseudhymenochirus). The relative length of the manual digits varies among species, though in all species these digits typically terminate in small bulblike tips. Being primarily aquatic frogs, these species have large hind limbs with fully webbed feet (i.e., extending to either the toe tip or journal.pone.0158910 base of the keratinous claw). The extent to which the pedal webbing is pigmented varies among species. As in most other frogs, the digits of the foot are longer than those of the hand, with the fourth toe being the longest and the first the shortest. As their common name of African clawed frogs SB856553 chemical information suggests, all species have dark brown orPLOS ONE | DOI:10.1371/journal.pone.0142823 December 16,7 /Six New Species of African Clawed Frog (Xenopus)black keratinous claws on the first three pedal digits; similar to the hand, those pedal digits that lack keratinous claws terminate in bulb-like tips. Many species have a keratinous claw on the prehallux, which in combination with other characters, can be diagnostic of particular species groups. The hands and feet lack subarticular tubercles, though scattered pustules are found on the plantar surface of some species. Female Xenopus are often identifiable by their protruding cloacal lobes.Ts just beyond the lower jaw, though species vary in the degree to which the rostrum is blunt or pointed. The canthus rostralis is typically flat to weakly concave, the loreal region is generally flat, and the internarial region varies from flat to weakly concave. All species lack a tongue and have a single opening to the Eustachian tubes. The floor of the mouth is typically wrinkled and covered in small pustules. The posteroventrally directed choanae are large, rounded, and largely or entirely visible in ventral view. Premaxillary and maxillary teeth jasp.12117 are present, but vomerine teeth are nearly always absent. The nares are prominent ellipsoid slits directed dorsally; a small sheet of skin projects from the margins of each naris, the extent and morphology of which varies among species but often features a laterally projecting nubbin. The size of the eye relative to the head varies among species as does the extent to which the eye is covered by the lower eyelid. In preservative, the pupil is typically round. Each eye is encircled by lateral-line plaques located on a raised ring of skin, though the degree to which this ring is observable varies based on specimen preservation. A subocular tentacle extends from the lateral margin of each eye; the length of this tentacle varies among species and is absent in two species (X. gilli and X. largeni). All species lack an externally visible tympanic annulus. The skin is generally smooth, although it can be covered by small spicules (especially those in the subgenus Silurana). A prominent feature of all adult Xenopus is the lateral-line system; the individual plaques (each comprising multiple sensory organs) resemble stitches. Distinct lateral-line rows extend across the skin of the head and dorsal, lateral, and ventral body. In both males and females, the medial surfaces of the manual digits are covered by small black punctiform spicules. In males, these are accentuated into nuptial pads comprising sheets of darkly pigmented spicules on the manual digits as well as on the upper arm, forearm, and sometimes axillary region. The forelimbs are typically moderately robust and have elongate manual digits that lack webbing (in contrast to other African pipids, the dwarf clawed frogs Hymenochirus and Pseudhymenochirus). The relative length of the manual digits varies among species, though in all species these digits typically terminate in small bulblike tips. Being primarily aquatic frogs, these species have large hind limbs with fully webbed feet (i.e., extending to either the toe tip or journal.pone.0158910 base of the keratinous claw). The extent to which the pedal webbing is pigmented varies among species. As in most other frogs, the digits of the foot are longer than those of the hand, with the fourth toe being the longest and the first the shortest. As their common name of African clawed frogs suggests, all species have dark brown orPLOS ONE | DOI:10.1371/journal.pone.0142823 December 16,7 /Six New Species of African Clawed Frog (Xenopus)black keratinous claws on the first three pedal digits; similar to the hand, those pedal digits that lack keratinous claws terminate in bulb-like tips. Many species have a keratinous claw on the prehallux, which in combination with other characters, can be diagnostic of particular species groups. The hands and feet lack subarticular tubercles, though scattered pustules are found on the plantar surface of some species. Female Xenopus are often identifiable by their protruding cloacal lobes.Ts just beyond the lower jaw, though species vary in the degree to which the rostrum is blunt or pointed. The canthus rostralis is typically flat to weakly concave, the loreal region is generally flat, and the internarial region varies from flat to weakly concave. All species lack a tongue and have a single opening to the Eustachian tubes. The floor of the mouth is typically wrinkled and covered in small pustules. The posteroventrally directed choanae are large, rounded, and largely or entirely visible in ventral view. Premaxillary and maxillary teeth jasp.12117 are present, but vomerine teeth are nearly always absent. The nares are prominent ellipsoid slits directed dorsally; a small sheet of skin projects from the margins of each naris, the extent and morphology of which varies among species but often features a laterally projecting nubbin. The size of the eye relative to the head varies among species as does the extent to which the eye is covered by the lower eyelid. In preservative, the pupil is typically round. Each eye is encircled by lateral-line plaques located on a raised ring of skin, though the degree to which this ring is observable varies based on specimen preservation. A subocular tentacle extends from the lateral margin of each eye; the length of this tentacle varies among species and is absent in two species (X. gilli and X. largeni). All species lack an externally visible tympanic annulus. The skin is generally smooth, although it can be covered by small spicules (especially those in the subgenus Silurana). A prominent feature of all adult Xenopus is the lateral-line system; the individual plaques (each comprising multiple sensory organs) resemble stitches. Distinct lateral-line rows extend across the skin of the head and dorsal, lateral, and ventral body. In both males and females, the medial surfaces of the manual digits are covered by small black punctiform spicules. In males, these are accentuated into nuptial pads comprising sheets of darkly pigmented spicules on the manual digits as well as on the upper arm, forearm, and sometimes axillary region. The forelimbs are typically moderately robust and have elongate manual digits that lack webbing (in contrast to other African pipids, the dwarf clawed frogs Hymenochirus and Pseudhymenochirus). The relative length of the manual digits varies among species, though in all species these digits typically terminate in small bulblike tips. Being primarily aquatic frogs, these species have large hind limbs with fully webbed feet (i.e., extending to either the toe tip or journal.pone.0158910 base of the keratinous claw). The extent to which the pedal webbing is pigmented varies among species. As in most other frogs, the digits of the foot are longer than those of the hand, with the fourth toe being the longest and the first the shortest. As their common name of African clawed frogs suggests, all species have dark brown orPLOS ONE | DOI:10.1371/journal.pone.0142823 December 16,7 /Six New Species of African Clawed Frog (Xenopus)black keratinous claws on the first three pedal digits; similar to the hand, those pedal digits that lack keratinous claws terminate in bulb-like tips. Many species have a keratinous claw on the prehallux, which in combination with other characters, can be diagnostic of particular species groups. The hands and feet lack subarticular tubercles, though scattered pustules are found on the plantar surface of some species. Female Xenopus are often identifiable by their protruding cloacal lobes.Ts just beyond the lower jaw, though species vary in the degree to which the rostrum is blunt or pointed. The canthus rostralis is typically flat to weakly concave, the loreal region is generally flat, and the internarial region varies from flat to weakly concave. All species lack a tongue and have a single opening to the Eustachian tubes. The floor of the mouth is typically wrinkled and covered in small pustules. The posteroventrally directed choanae are large, rounded, and largely or entirely visible in ventral view. Premaxillary and maxillary teeth jasp.12117 are present, but vomerine teeth are nearly always absent. The nares are prominent ellipsoid slits directed dorsally; a small sheet of skin projects from the margins of each naris, the extent and morphology of which varies among species but often features a laterally projecting nubbin. The size of the eye relative to the head varies among species as does the extent to which the eye is covered by the lower eyelid. In preservative, the pupil is typically round. Each eye is encircled by lateral-line plaques located on a raised ring of skin, though the degree to which this ring is observable varies based on specimen preservation. A subocular tentacle extends from the lateral margin of each eye; the length of this tentacle varies among species and is absent in two species (X. gilli and X. largeni). All species lack an externally visible tympanic annulus. The skin is generally smooth, although it can be covered by small spicules (especially those in the subgenus Silurana). A prominent feature of all adult Xenopus is the lateral-line system; the individual plaques (each comprising multiple sensory organs) resemble stitches. Distinct lateral-line rows extend across the skin of the head and dorsal, lateral, and ventral body. In both males and females, the medial surfaces of the manual digits are covered by small black punctiform spicules. In males, these are accentuated into nuptial pads comprising sheets of darkly pigmented spicules on the manual digits as well as on the upper arm, forearm, and sometimes axillary region. The forelimbs are typically moderately robust and have elongate manual digits that lack webbing (in contrast to other African pipids, the dwarf clawed frogs Hymenochirus and Pseudhymenochirus). The relative length of the manual digits varies among species, though in all species these digits typically terminate in small bulblike tips. Being primarily aquatic frogs, these species have large hind limbs with fully webbed feet (i.e., extending to either the toe tip or journal.pone.0158910 base of the keratinous claw). The extent to which the pedal webbing is pigmented varies among species. As in most other frogs, the digits of the foot are longer than those of the hand, with the fourth toe being the longest and the first the shortest. As their common name of African clawed frogs suggests, all species have dark brown orPLOS ONE | DOI:10.1371/journal.pone.0142823 December 16,7 /Six New Species of African Clawed Frog (Xenopus)black keratinous claws on the first three pedal digits; similar to the hand, those pedal digits that lack keratinous claws terminate in bulb-like tips. Many species have a keratinous claw on the prehallux, which in combination with other characters, can be diagnostic of particular species groups. The hands and feet lack subarticular tubercles, though scattered pustules are found on the plantar surface of some species. Female Xenopus are often identifiable by their protruding cloacal lobes.