Amietophrynus channingi, Barej, Michael F., Schmitz, Andreas, Menegon, Michele, Hillers, Annika, Hinkel, Harald, Böhme, Wolfgang & Rödel, Mark-Oliver, 2011

Barej, Michael F., Schmitz, Andreas, Menegon, Michele, Hillers, Annika, Hinkel, Harald, Böhme, Wolfgang & Rödel, Mark-Oliver, 2011, Dusted off — the African Amietophrynus superciliaris - species complex of giant toads, Zootaxa 2772, pp. 1-32 : 18-24

Amietophrynus channingi sp. nov.

Figs. 1 , 2 c, 4c, 10a–d, 11a–d, 12a–c.

Holotype. MTSN 9674 (male) Democratic Republic of Congo, West Mwana, Itombwe Massif, 0 28.13875 E, 0 3.83781 S, 1302 m a.s.l., coll. Joseph Matunguru.

Paratypes. IRSNB-KBIN 1982 (female) Democratic Republic of Congo, Beni; IRSNB-KBIN 1983 (subadult) Democratic Republic of Congo, Mutsora; IRSNB-KBIN 1984 (female) Democratic Republic of Congo, Bukavu; IRSNB-KBIN 1985 (juvenile) Democratic Republic of Congo, Irangira; MHNG 2520.25 (juvenile) Democratic Republic of Congo, Nduye, Alamby; ZFMK 62573 (male) Democratic Republic of Congo, Irangi; ZFMK 63895-6 (2 juveniles) Democratic Republic of Congo, Irangi.

Additional material. IRSNB-KBIN 634 (male) Democratic Republic of Congo, Lulenga; IRSNB-KBIN 2216 (female) Democratic Republic of Congo, Zobia; IRSNB-KBIN 2217 (female) Democratic Republic of Congo, Zobia; IRSNB-KBIN 11363 (female) Democratic Republic of Congo, Walikale; IRSNB-KBIN 11364 (female + 2 juveniles) same data as IRSNB-KBIN 1985; MNHN 1933.027 (female) Congo Belge (= Dem. Rep. Congo), locality unknown; ZFMK 34376 (juvenile) Democratic Republic of Congo, Poko; ZFMK 63894 (male) same data as ZFMK 63895.

Remark: The MNHN received a collection from “ Congo Belge ” in 1933 from Guy Babault (Bull. Mus. Natl. Hist. Nat. p. 18), today Democratic Republic of Congo, without further details on the collection localities. According to publications dealing with various taxa donated to the MNHN by G. Babault ( Pellegrin 1933, 1935; Babault 1935; Berlioz 1935; Germain 1936) the locality in “ Congo Belge ” can be assigned to the Kivu area in eastern Democratic Republic of the Congo. Consequently, we assign MNHN 1933.027 to this new taxon.

Diagnosis. Genetically the taxon belongs to the African toad genus Amietophrynus ( Frost et al. 2006) . As part of the Amietophrynus superciliaris -species complex, the taxon differs from all other members of the genus by a smooth dorsal skin in adult specimens, straight loreal region and large size.

Medium to large sized toad with smooth dorsal skin in adults, granular in juveniles; body shape compact; tympanum distinct, drop-shaped, smaller than eye-diameter; parotids prominent, broad, width of parotid glands hardly reducing backwards, posterior tips of parotid glands rounded; eyelid slightly triangular in dorsal view, eyelid in lateral view forming a intimated triangular process; anterior and posterior part of back with different pattern; pair of dark spots present on posterior back region; extremities slender.

Amietophrynus channingi sp. nov. is most similar to A. s. superciliaris as both species exhibit a triangular eyelid process in adults, a structure lacking in A. s. chevalieri ( Figs. 2 a–c) and share the symmetric pair of abdominal spots ( Figs. 3 c, e–g; 11b, c). The new species differs from A. s. superciliaris by the following characters: shape of eyelid being more pointed and elongated in A. s. superciliaris ; the eyelid width / eye diameter ratio shows no significant difference (Kruskal-Wallis-test; p> 0.05, N A.s.s.= 28, 0.24–0.39, x= 0.32 ± 0.04; N A.c.= 10, 0.23–0.38, x= 0.34 ± 0.04; H= 12.28); shape of parotid glands, much diminishing in width posteriorly and possessing a pointed tip in A. s. superciliaris and being more bulged and rounded at the posterior tip in A. channingi sp. nov.; colouration of the back, which is darker in the posterior region of the back and possesses a darker mid-dorsal line in A. channingi sp. nov., whereas the dorsum is more or less uniformly coloured in A. s. superciliaris ( Figs. 3 c, e–g; 11a–c); colouration of flanks, being reddish in A. s. superciliaris and brownish in the new species ( Figs. 2 b–c). Moreover, juveniles without a fully developed eyelid process can be differentiated by the following colour patterns: interorbital pattern in juvenile A. channingi sp. nov. a depressed dark, V-like figure, covering the eyelids, while juvenile A. s. superciliaris usually possess two clearly separated interorbital spots, which may even be broken into numerous smaller spots ( Figs. 4 b-c).

The new species can be distinguished from A. s. chevalieri by the following characters: eyelid process being absent in A. s. chevalieri (present in A. channingi sp. nov.; Figs. 2 a, c); the eyelid width / eye diameter ratio is significantly higher in adults of the new species (Kruskal-Wallis-test; p <0.01, N A.s.c.= 7, 0.20–0.33, x= 0.24 ± 0.05; N A.c.= 10, 0.23–0.38, x= 0.34 ± 0.04; H= 12.28); palmar tubercles more prominent in A. s. chevalieri ; A. channingi sp. nov. possess a symmetric pair of abdominal spots (lacking in A. s. chevalieri ; Figs. 9 a–f, h; 11a–c); lateral colouration being reddish-purple in A. s. chevalieri and brownish in A. channingi sp. nov. ( Figs. 2 a, c).

Description of the holotype. The holotype is an adult male in breeding condition; dorsal skin smooth, lateral and ventral skin rough ( Figs. 10 b, c); compact and sturdy body shape; SUL 111.8 mm; head without bony ridges; canthus rostralis distinct, angular; loreal region slightly concave; snout very short, almost straight in lateral view; head width 44.1 mm; eye-diameter 12.2 mm; interorbital-distance 9.5 mm; nares closer to snout than to eye; eyelid with weak triangular process ( Fig. 11 a), measuring 4.9 mm from lower eyelid border to tip of eyelid process; parotid length 33.5 mm; parotid width 11.8 mm; parotids bi-coloured, upper part pale brown like dorsum, lower part dark grey; gland openings present only on upper part, reaching colouration border; posterior to parotids a glandular dorsolateral fold, extending to groin area; fingers and toes simple; subarticular tubercles simple; relative length of fingers: III> I> II ≥ IV; femur length 42.6 mm; tibia length 42.0 mm; foot length incl. longest toe 43.6 mm; inner metatarsal tubercle oval and prominent; outer metatarsal tubercle rounded, indistinct; manual webbing absent ( Fig. 10 c), relative toe length: IV> III> V> II> I; pedal webbing rudimentary ( Fig. 10 d): 1 (0.5), 2 (1-0.5), 3 (2-1.25), 4 (2.75-3), 5 (1.25); tarsal fold absent; secondary sexual characters: large dark nuptial pads on fingers I and II; miniscule spines scattered on lateral side of head and flanks below parotid glands, minuscule spines denser behind mouth gap; further minuscule spines cover anterior and dorsal side of upper arms; colouration in preservation: back pale brown; interorbital space with darker V-shaped pattern, the tips of the V pointing on the eyelid processes; dark vertebral line running backwards ( Figs. 10 b; 11b); posterior part of back with dark triangular figure and a symmetric pair of dark spots; skin of dark spots different in texture to remaining of back skin, blunt and “fleecy”; dorsal and lateral colouration distinctly different, separated by thin white line; flanks coloured dark brown, this pattern ranging from snout-tip backwards and dissolving in the inguinal area, here replaced by dark brown spots (three on left, two on the right side); dark spots on anterior part of upper hind limb and on posterior side of lower hind limb; venter uniform pale.

Variation. Medium to large sized toad with compact body shape; females being larger than males (SUL in males: 106.7–111.8 mm, in females: 100.3–143.0 mm; SUL of specimens from Congo according to Noble (1924: males: 98–112 mm, females: 133–149 mm); mean head width similar in both sexes, in males 38% of SUL, in females 39%; snout in lateral view straight almost truncate; distance eye-snout larger than eye diameter; eyelid in adult specimens more or less triangular shaped; tympanum more or less distinct, positioned in a concave area of the cheeks; tympanum vertically prolonged and drop shaped, smaller in horizontal diameter than eye-diameter; dorsal skin smooth in adults, granular in juveniles; parotid glands prominent, bulged, width posteriorly slightly reducing, usually rounded at posterior tip (parotid length / parotid width ratio in males: 2.82, in females: 2.73); glandular dorsolateral fold behind the parotids may be present; parotids bicoloured, lower parts like flanks, upper parts like back; border of the two parts forms a sharp ridge; parotid gland openings on upper part only; fingers and toes simple; subarticular tubercles simple; relative length of fingers: III> I> II ≥ IV (mean length of finger I / length of finger III ratio in males: 89%, in females: 94%); manual webbing absent; extremities slender in comparison to body shape; mean tibia length 40% of SUL in males, in females 41%; inner metatarsal tubercle present, oval and prominent; outer metatarsal tubercle rounded, sometimes indistinct; relative toe length: IV> III> V> II> I; webbing rudimentary: 1 (0.5), 2 (1-0.5), 3 (2-1) or 3 (2-1.5), 4 (2.75-2.75) or 4 (2.75-3), 5 (1.25); males in breeding condition with hypertrophied forearms and swellings on fingers I and II.

Colouration. Dorsum dirty yellowish-browinish, extending from the tip of the snout, along the upper side of head and parotids backwards to the posterior part of the back ( Fig. 11 ); dark V-shaped pattern on head covering the eyelids, usually a vertebral line running from this pattern backwards, forming a dark triangular pattern on the posterior part of the back ( Figs. 11 b, c); back with symmetric pair of dark spots; loreal area, lower parts of parotids and flanks brownish; upper parts of lateral colouration darker than ventral part, partly almost black, posterior most part of flanks orange-brown; forearms light purple-greyish above, usually bordered by white line, and dark below; inguinal region with small black spots; upper hind limbs and feet with black transversal bars ( Figs. 11 c, d); forearms with distinct white line between pale dorsal and dark ventral colouration; throat and venter pale yellow; juveniles coloured like adults but may possess additional pairs of spots on the back and the interorbital V-pattern, covering large parts of the eyelids; this pattern is more distinct in juveniles than in adults; juveniles with additional transversal bars on tibiofibula, this pattern disappearing in larger specimens.

Orts (1970) figured two specimens after completed metamorphosis: the first uniform brown-blackish coloured and the second with a “typical toad pattern” consisting of symmetric pairs of spots (as in A. regularis , A. camerunensis , etc.). According to Orts (1970) the typical interorbital V-pattern develops within the first two weeks.

Colouration in preservation. Preserved specimens still exhibit the separation of dark and light colour as in life; dark V-pattern between eyes, vertebral line and darker triangular posterior region of back may be hardly or not visible; flanks turn greyish or yellowish, and the brownish colour may turn almost black; brownish flank colouration sometimes recognizable when the lateral skin got folded and remains of former colouration has been covered between folds; pair of dark spots on the posterior part of the back sometimes bleached out and hardly recognizable.

Tadpole description. The tadpole of this new taxon has been briefly described by Orts (1970). According to Orts’ (1970) description and figures: body oval in dorsal view in young stages, becoming more elongated in later stages ( Figs. 12 a–c); body slightly flattened; mascular tail slender, converging caudally; dorsal and ventral fin present, tail (fins included) of similar height as body; tail fin rounded at tip of tail; tail 1.33 to 1.75 as long as body; eyes dorsally positioned, moving into more lateral position during growth, distance snout-tip to eye approx. 20–25% of body length; spiraculum positioned at midbody; mouth ventrally positioned, surrounded by robust lips; colouration at 10 mm total length: grey above and crème-white, translucent below; tadpoles of 10.5 mm length (4 mm body length, Gosner stage 25; Fig. 12 a) with keratodont formula: 1:1+1//1+1:2; development of posterior pats at length of 13 mm (body length 5 mm); keratodont formula: 1:1+1//3 (tadpole length> 13 mm); same keratodont formula in later stages; metamorphosis finished at body length (measured from tip of snout to anus) of 9 to 10 mm; for more details see Orts (1970).

Natural history. Although the taxonomic status of this species has so far been overlooked, much more about the natural history of this taxon has been published compared to the other taxa of the Amietophrynus superciliaris - species complex. A. channingi sp. nov. is active in the rainy season, and can then be observed almost everywhere in the forest (Noble 1924). The species is nocturnal at least in captivity, where also cannibalistic behaviour was recorded ( Orts 1970). When disturbed, the toad may be feigning death by “lowering the head to the ground, and dropping the prominent upper eyelid” (Noble 1924). The diet comprises various invertebrate taxa (Noble 1924). The species seems to feed preferably on snails around the Irangi research station ( DRC) as local research assistants regularly found the species in great numbers in pits dug by road workers to raise snails for food consumption. According to Noble (1924) oviposition may occur during several months, breeding thus potentially may take place throughout most of the year. Eggs are very numerous in comparison to other forest toads, 1200–1500 in Amietophrynus tuberosus (referred to as A. polycercus in Noble 1924) and up to three times that number in A. channingi sp. nov., and egg size ranges from 1.6–2.0 mm (envelopes removed). According to own measures, egg size ranges from 1.40–1.95 mm (N= 114, mean= 1.69, SD= 0.11). Orts (1970) recorded tadpoles of 10 mm in Irangi in Democratic Republic of Congo in mid-June, at the end of the rainy season. He observed more than 3000 tadpoles in a puddle of only of 40 x 25 cm and 7 cm depth, covered with vegetation, where tadpoles moved on the ground and among leaf litter. Other tadpoles inhabited a series of puddles of a diameter of approximately one meter in mid- April. These breeding sites were connected to small rivers, which may transform into large currents after rain and then wash the tadpoles away ( Orts 1970).

1 2 3 4 5 6 7 8 9

A. brauni (N= 3) 0 ± 0

GenBank

A. poweri (N= 2) 0.0428 - 0.0446 0.0018

GenBank 0.0439 ± 0.0007

A. rangeri (N= 2) 0.0611 - 0.0720 0.0648 - 0.0700 0.0018

GenBank 0.0668 ± 0.0050 0.0674 ± 0.0022

A. channingi (N= 2) 0.0805 - 0.0849 0.0648 - 0.0673 0.0648 - 0.0685 0.0000

D.R. Congo 0.0831 ± 0.0020 0.0687 ± 0.0017 0.0666 ± 0.0021

A. s. chevalieri (N= 4) 0.0772 - 0.0814 0.0669 - 0.0682 0.0557 - 0.0612 0.0218 - 0.0219 0 ± 0

Guinea, Liberia 0.0793 ± 0.0022 0.0676 ± 0.0007 0.0584 ± 0.0029 0.0218 ± 0.0000

A. s. superciliaris (N= 2) 0.0732 - 0.0779 0.0673 - 0.0719 0.0574 - 0.0650 0.0274 - 0.0286 0.0085 - 0.0101 0.0017 Cameroon, Nigeria 0.0754 ± 0.0018 0.0696 ± 0.0020 0.0612 ± 0.0041 0.0280 ± 0.0007 0.0093 ± 0.0008 A. camerunensis (N= 2) 0.0734 - 0.0780 0.0687 - 0.0730 0.0634 - 0.0725 0.0776 - 0.0809 0.0759 - 0.0789 0.0787 - 0.0823 0.0035 GenBank 0.0751 ± 0.0019 0.0709 ± 0.0023 0.0679 ± 0.0043 0.0792 ± 0.0018 0.0774 ± 0.0016 0.0802 ± 0.0016 A. gutturalis (N= 2) 0.0807 - 0.0864 0.0828 - 0.0861 0.0756 - 0.0840 0.0757 - 0.0774 0.0825 - 0.0840 0.0797 - 0.0839 0.0502 - 0.0540 0.0018 GenBank 0.0839 ± 0.0021 0.0843 ± 0.0015 0.0791 ± 0.0036 0.0765 ± 0.0009 0.0833 ± 0.0008 0.0818 ± 0.0019 0.0521 ± 0.0016 A. tuberosus (N= 1) 0.1049 - 0.1067 0.1138 - 0.1153 0.0873 - 0.0939 0.0927 - 0.0930 0.0946 - 0.0962 0.0894 - 0.0932 0.0902 - 0.0926

0.0928 ± 0.0000 ---

GenBank 0.1055 ± 0.0010 0.1146 ± 0.0010 0.0906 ± 0.0047 0.0928 ± 0.0002 0.0954 ± 0.0012 0.0913 ± 0.0027 0.0914 ± 0.0017 Distribution. Amietophrynus channingi sp. nov. is known from various localities in the eastern Democratic Republic of Congo, East Lower Guinea ( Boulenger 1919; Wheeler 1922; Noble 1924; Loveridge 1936; Orts 1970). One specimen (IRSNB-KBIN 10385) is labelled as originating from “Mutsora, Rwanda ”, but, given coordinates reveal that the locality is situated in the Democratic Republic of Congo. Due to the vicinity of localities of A. channingi sp. nov. close to the eastern border of the Democratic Republic of Congo ( Fig. 1 ), the distribution of the toad may cover westernmost parts of Uganda, Rwanda and Burundi in suitable habitats. However, recent herpetological works failed to detect the species in the Albertine Rift ( Drewes & Vindum 1994; Vonesh 2001).

Ethnozoology. According to Noble (1924) natives fear the whitish secretion, as they might go blind.

Etymology. The specific epithet channingi is a patronym. We name the species in honour of Prof. Dr. Alan Channing from the University of the Western Cape ( South Africa) in recognition of his invaluable contributions to our knowledge of African amphibians.

Figures

FIGURE 1. Distribution of Amietophrynus channingi sp. nov. (red), A. superciliaris chevalieri (green) and A. s. superciliaris (blue, the purple spot refers to a specimen which was dried up, see text). Type localities are marked with a “ H ”, vouchers from localities marked with an asterisk (*) were not available and are added from literature. Locality symbols with an embedded question mark “? ” refer to imprecise recordings. I. West Africa: H = Ivory Coast (A. superciliaris chevalieri); II. western Central Africa: H 1 = Rio del Rey, Cameroons (A. s. superciliaris), H 2 = South Cameroon (A. laevissimus, synonym of A. s. superciliaris); III. eastern Central Africa: H = Democratic Republic of Congo, West Mwana (A. channingi sp. nov.).

FIGURE 2. Head in lateral view, showing shape of eyelid in adult specimens (insets show how to measure width of eyelid): Amietophrynus s. chevalieri (a; photo: C. Brede); A. s. superciliaris (b); A. channingi sp. nov. (c). Note the pointed eyelid in (b) and (c) forming a triangular eyelid process in lateral view.

FIGURE 3. Colour pattern in Amietophrynus s. superciliaris; juvenile from Cross River National Park, Nigeria (a); adult from Mezam, Cameroon (b); adult from Dikume Balue, Cameroon (c, d); adults from Bamenda, Cameroon (e, f: photos: V. Gvoždík); g) adult from Gabon (photo: Overmas).

FIGURE 4. Pattern of head markings in juvenile Amietophrynus s. chevalieri, A. s. superciliaris and A. channingi sp. nov. (specimens in lines from left to right; SUL in mm given in brackets). A. s. chevalieri (a): line 1: ZMB 74322 (22.3 mm); A. s. superciliaris (b): line 2: MHNG 757.61 (42.4 mm); MHNG 917.99 (46.2 mm); MHNG 955.89 (59.3 mm); MHNG 1018.88 (47.5 mm); line 3: MHNG 1018.91 (30.9 mm); MHNG 1390.97 (18.2 mm); ZFMK 67268 (17.0 mm); ZFMK 73192 (30.4 mm); line 4: ZMB 19924 (57.2 mm); ZMB 19971 (35.5 mm); ZMB 19972 (34.9 mm); ZMB 19973 (30.7 mm); line 5: ZMB 74319 (19.3 mm); ZMB 74522 (38.3 mm); A. channingi sp. nov. (c) line 6: MHNG 2520.25 (36.3 mm); ZFMK 34376; ZFMK 63895 (27.0 mm); ZFMK 63896 (21.3 mm); line 7: IRSNB-KBIN 1985, IRSNB-KBIN 11364 (2 juveniles).

FIGURE 9. Colour pattern in Amietophrynus s. chevalieri; subadult (a) and juvenile (b) from North Lorma National Park, Liberia; juveniles (c, f) and subadults (d, e), from Sérédou, Guinea (photos c, e, f: J. Köhler; photo d: P. Naskrecki); adult from Gola National Park, Sierra Leone (g); subadult from Taï National Park, Ivory Coast (h).

FIGURE 10. Holotype of Amietophrynus channingi sp. nov. in lateral view (a); dorsal view (b); details of hand (c); details of foot (d).

FIGURE 11. Colour pattern in Amietophrynus channingi sp. nov. holotype (a, b) from Mwana, Democratic Republic of Congo; adult (c, d) from Irangi, Democratic Republic of Congo.

FIGURE 12. Tadpole of A. channingi sp. nov. (modified after Orts 1970; scale bar mouth: 1 mm; scale bar tadpole: 10 mm): Gosner stage 25 (a): tadpole mouth, dorsal, lateral and ventral view; Gosner stage 26 - 28 (b): tadpole mouth, dorsal, lateral and ventral view; Gosner stage 36 - 37 (c): dorsal, lateral and ventral view.