Toxicodryas adamanteus, Greenbaum & Allen & Vaughan & Pauwels & Wallach & Kusamba & Muninga & Aris- Tote & Mali & Badjedjea & Penner & Rödel & Rivera & Sterkhova & Johnson & Tapondjou & Brown, 2021

Greenbaum, Eli, Allen, Kaitlin E., Vaughan, Eugene R., Pauwels, Olivier S. G., Wallach, Van, Kusamba, Chifundera, Muninga, Wandege M., Aris- Tote, Mwenebatu M., Mali, Franck M. M., Badjedjea, Gabriel, Penner, Johannes, Rödel, Mark-Oliver, Rivera, Jacqueline, Sterkhova, Viktoria, Johnson, Grant, Tapondjou, Walter P. & Brown, Rafe M., 2021, Night stalkers from above: A monograph of Toxicodryas tree snakes (Squamata Colubridae) with descriptions of two new cryptic species from Central Africa, Zootaxa 4965 (1), pp. 1-44 : 27-32

Toxicodryas adamanteus sp. nov.

( Table 2, Figs. 8 , 12–13 )

We hypothesize that this new, cryptic species occurs in western, central and eastern Africa, east of the Niger Delta, and it has been considered to be conspecific with Toxicodryas pulverulenta since it was first documented to occur in Angola by Peters (1877). The recognition of this new species is supported by evidence from molecular data ( Fig. 2 ) and significant differences in subcaudal scale counts (see Results).

Diagnosis. A species of Toxicodryas restricted to West, Central and East Africa, east of the Niger Delta, defined by the following combination of characters: maximum SVL <1 meter (vs. maximum SVL> 1 meter in T. blandingii and T. vexator sp. nov.), DSRN 18–23 (vs. 23–25 in T. blandingii and 23–29 in T. vexator sp. nov.), DSRM 18–21 (vs. 21–25 in T. blandingii and T. vexator sp. nov.); cloacal plate undivided (vs. usually divided in T. blandingii , and divided or undivided in T. vexator sp. nov.); both sexes brown to pink with darker cross-bars that often enclose a whitish spot, and the dorsum and venter sprinkled with fine dark brown or black spots (vs. adult males glossy or velvety black with a yellow venter, and adult females light brown, gray, or yellowish-brown with light-brown or cream cross-bars on the flanks, with yellowish-brown venters in T. blandingii and T. vexator sp. nov.); hemipenis relatively long with long spines mid-way along the shaft that decrease in size towards the apex and base, with a domed apex (vs. hemipenis relatively short and massive [i.e., broad], proximal third covered with spines, distal twothirds dimpled with a flattened apex in T. blandingii and T. vexator sp. nov.).

Holotype. UTEP 22204 (field no. ELI 2213; Figs. 8 , 12–13 ), adult male from Npenda village , NE of Lake Tumba (00.7465° S, 18.2243° E, 311 m), Equateur Province, DRC, collected by local Twa people and brought to Eli Greenbaum, Chifundera Kusamba, Wandege M. Muninga, and Mwenebatu M. Aristote on 8 July 2013.

Paratopotype. UTEP 22203 (field no. ELI 2212) adult female with same collection details as the holotype.

Paratype. RBINS 2699 (formerly RBINS 9127) (field no. Paul Leloup #26), adult female from Région Tshabondo (2.690861° S, 27.341972° E), South Kivu Province , DRC, collected by Paul Leloup on 11 October 1958 .

Description of the holotype. Adult male, 812 mm SVL; head weakly triangular and moderately distinct from neck, 2.4% of SVL (19.3 mm); interocular distance 13.4 mm, pupil elliptical, eye diameter 5.2 mm; loreal nearrectangular, shorter (1.7 mm) than high (2.0 mm), slightly tapering superiorly and vertically; body semi-triangular; tail moderately long (27.7% of SVL). Supralabials 8/8, 3 rd –5 th /3 rd –5 th contacting orbit; infralabials 13/12, 1 st on each side in contact behind mental, 1 st –5 th /1 st –5 th contacting anterior chin shields and 5 th –7 th /5 th –7 th contacting posterior chin shields; 1/1 preocular; 2/2 postoculars; temporals 2 + 3 + 3/2 + 3 + 3; 2 internasals; nasal divided; frontal width and length equal (6.6 mm); dorsal scale rows 21 one head length posterior to jaw rictus, 19 at midbody, 15 one head length anterior to vent, smooth and oblique with apical pits visible on the neck, vertebral scales broad and apically flattened; ventrals 264 (standard), 262 (Dowling); cloacal plate undivided; paired subcaudals 117; both hemipenes everted.

Coloration (in life) of the holotype. Silvery gray-brown over the entire length of the dorsum including the head, with similarly colored but darker diamonds occurring laterally over the full length of the neck, body, and tail. These diamonds are elongated vertically, have pale gray centers, and often have black spots at the top and bottom corners. Between each diamond on the body and neck is a more vaguely defined, pale gray diamond or stripe. The lateral and antero-dorsal sides of the head are speckled, as is the ventral side of the head, neck, body, and tail. The venter is otherwise white, with the speckles forming two pale stripes running down either side of the ventrals and subcaudals. The base of the tongue is orangish red, and the forked tip is silvery white with black edging.

Coloration (in preservative) of the holotype. This specimen’s coloration has become slightly darker and browner than it was in life, with less pronounced patterning on the flanks, but otherwise the appearance is similar to the coloration in life.

Variation. Morphometric variation of Toxicodryas adamanteus sp. nov. is shown in Table 2. We observed extensive temporal scale variation, including 1 + 1, 1 + 2, 2 + 2 (most commonly), 2 + 3, 2 + 5, 3 + 2, 3 + 3, and 4 + 3. Chabanaud (1917c) described a male from Gabon with supralabials 3–6 contacting the eye, and this specimen seems to be the size record at 1,225 mm total length (995 mm SVL, 230 mm tail length). Schmidt (1923) listed ventral counts of 251–269 in snakes from DRC, and noticed one individual that had a preocular fused to the supraocular on one side, and in two individuals, the loreal was fused to the lower portion of the preocular and thus contacted the eye. Laurent (1956) noticed that snakes from DRC (i.e., T. adamanteus sp. nov.) had more subcaudals than snakes from West Africa (i.e., T. pulverulenta ). Skinner (1973) noted ventral scale counts range from 240–269, subcaudal scale counts range from 105–126 (identical to Pitman 1974), and the maximum size is about 2 meters, substantially larger than all other published records, and thus, highly doubtful. De Witte (1975) provided data for ventral scale counts of DRC snakes ranging from 235–242 (males) and 239–249 (females), and subcaudal counts of 112–120 (both sexes). Spawls & Branch (2020) listed the maximum size as “about 1.25 m ” but no specific locality or record was provided. Although most of our examined specimens and literature records noted the 3 rd to 5 th supralabial in contact with the eye, some individuals have the 4 th to 6 th supralabial in contact with the eye (e.g., Loveridge 1937) and one specimen from Gabon (CAS 258155) had only the 4 th and 5 th supralabial in contact with the eye. In snakes from Uganda, Pitman (1974) reported ventral scale counts of 240–269 and subcaudal counts of 105–126 (not distinguished by sex). In de Witte’s (1975) study of snakes from Virunga National Park in eastern DRC, he noted ventrals range from 235–242 in males and 239–249 in females; subcaudals ranged from 112–120 in both sexes. Rasmussen (1997b:106) described individuals with 3 or 4 postoculars, 7–9 supralabials, 9–13 infralabials, 236–278 ventrals, and 96–132 subcaudals (sometimes undivided). In general, he noted this species has sloping and smooth scales with apical pits, and the vertebral row is more or less enlarged.

Bogert (1940:fig. 8) illustrated the maxillary teeth of a specimen (AMNH 50590) from former French Cameroon, noting “ five specimens examined show variation from eleven to thirteen anterior subequal teeth followed after a very short diastema by two larger grooved fangs and a smaller fang, the total number of teeth being fourteen to eighteen.” Because only two of his examined specimens originated from former French Cameroon, at least three of these specimens are from Liberia, which are attributable to T. pulverulenta .

Schmidt (1923:103) quoted field notes of Herbert Lang for DRC snakes as “coloration, in life, reddish brown above, head darker brown. Irregular dark gray lateral bars, wider in the middle, extend from the vertebral line to the venter, tipped above and below with black. A cream-colored central spot in the broad portion of each lateral bar. Faint narrow grayish crossbars between the wider ones, disappearing posteriorly. The wider crossbars are usually alternate, sometimes confluent on the back. Venter pinkish gray, heavily dotted with brown which forms two lines at the inner edges of the ventral edges of the ventral angle. These lines are more distinct beneath the tail.” Hellmich (1957b) described several individuals from Angola with a reddish brown to reddish blue-gray dorsum, with varying degrees of contrasting rhombic patterns and spots. Pitman (1974) provided a similar description for specimens from Uganda, noting they range from pinkish-brown to reddish-brown. Hedges (1983:21) described Kenyan specimens as, “a rather pretty pattern of coffee coloured diamond shaped markings on a mushroom pink body.” Rasmussen (1997b) described coloration in this species (presumably based on examined specimens from Nigeria and Cameroon) as reddish brown on the dorsum of the body; dorsum of the head darker brown; irregular, dark gray, diamondshaped spots on the flanks that are widest at mid-body; spots edged in black on superior and inferior edges with a cream spot in the center that sometimes fuse together in the midline; faint grayish transverse bands between spots that fade and disappear posteriorly; venter pinkish-gray, with dense brown spots that form a line just inside and parallel to the keeled ventrals, most salient on the tail. Pauwels et al. (2019b) noted a specimen from Gabon with an orange tongue in life. Spawls & Branch (2020:239) noted the dorsal color can range from pinkish to brown, redbrown or pinky gray with “darker” cross-bars that enclose a “pale” spot. The dorsum and venter are “finely dusted” with brown or black specks, whereas the venter is pale pink with “dashed dark lines” on each side of the ventrals. Contrary to Pauwels et al. (2019b), they noted the tongue is pink with a white tip. Based on our photographs of DRC snakes (e.g., Fig. 12G ), the tongue is orangish red, and the forked tip is silvery white with black edging, which is consistent with the coloration of the holotype in life (EG pers. obs.). An unsexed individual from Banalia, DRC ( Fig. 12F ) is unique in having a golden yellow mid-dorsal stripe.

Diet. Pitman (1938) mentioned a juvenile from Uganda that had a small mouse in its stomach. In Kenya, Hedges (1983) noted the species eats small chameleons, geckos, and frogs. Butler & Reid (1990) described an adult female from Nigeria that contained the remains of an Agama sp. lizard (sensu Leaché et al. 2017). Spawls & Branch (2020) listed the diet as arboreal lizards and rodents.

Parasites. Pitman (1938) noted a juvenile from Uganda with numerous ticks.

Behavior. Pitman (1974:128) described the species as “arboreal, nocturnal... amiable disposition,” and suggested that it might rely on camouflage to avoid predation, a sentiment also suggested by Gans (1961). Chirio & LeBreton (2007) suggested the species is shy and rarely bites. Spawls & Branch (2020) noted that when threatened, it elevates the anterior part of its body, “flickers its red tongue,” hisses, and strikes.

Reproduction. Schmidt (1923) described a DRC female collected in June 1914 with an unspecified number of eggs that measured 11 x 29 mm. Butler & Reid (1990) described an adult female from Nigeria (captured 21 January 1988) that contained two developing eggs (34–35 mm long, 11 mm wide). Branch (2005) noted the species lays 2– 5 eggs.

Habitat. Parker (1936) noted this species is restricted to rain forest and “its outliers.” Perret (1961) listed the species from forest in Cameroon. De Witte (1962) listed the habitats for DRC snakes as equatorial forest and gallery forest, and this classification was repeated by Thys van den Audenaerde (1965). Blackwell (1967) listed the species from forest, thickets, and gardens in Nigeria. Pitman (1974:128) described this snake as a “forest species” in Uganda, but also noted one individual from a “fowl house,” and another from an epiphytic fern ( Platycerium angolense ) on a forest tree. Butler & Reid (1986) listed the species only from forest in Nigeria. Lawson (1993) documented the species from forest and “farmbush” in Cameroon. Rasmussen (1997b) described the species as nocturnal and restricted to forest. Chirio & LeBreton (2007) recorded the species from forests and savanna-forest mosaic in Cameroon. Spawls & Branch (2020) included forest, woodland, and forest-savanna mosaic from sea level to about 2,000 m elevation. Among the 19 snake species recorded within the garden of a villa in Yenzi (2.77261° S, 10.03403° E), Gamba, Nyanga Province, southwestern Gabon (forest-savanna mosaic), inhabited by one of the authors from 2004 to 2011 (OSGP, unpubl. data), T. adamanteus sp. nov. was among the most rarely encountered species.

Geographic distribution and habitat. Based on molecular data from Allen et al. (in press) and patterns of our morphometric data ( Table 2), we hypothesize that this species occurs east of the Niger Delta in Nigeria, Cameroon, Equatorial Guinea, Gabon, CAR, Republic of Congo, DRC, Angola, Uganda, South Sudan, and Kenya. Ullenbruch & Böhme (2017) recently listed the species from South Sudan.

Venom. Based on a specimen from Cameroon, Taub (1967) described the histological morphology of the Duvernoy’s gland. Venom composition and effects are unknown ( Weinstein et al. 2011).

Etymology. The specific epithet adamanteus is a Latin adjective referring to the diamond-shaped marks on the flanks and dorsum of this species.

Figures

FIGURE 2. A time-calibrated Bayesian phylogeny of Toxicodryas, based on the cyt b and c-mos genes, modified from Allen et al. (in press). Highly supported nodes (posterior probability ≥ 0.9) are denoted with a black circle. Node bars represent 95% confidence intervals. RADseq (2848 loci) phylogenies showed identical topologies. The five clades supported as distinct species by all species-delimitation analyses of Allen et al. (in press) are shown as black, white, and gray rectangles. Toxicodryas adamanteus sp. nov. includes all populations in Central Africa, including Cameroon, Gabon, and Democratic Republic of the Congo. Outgroups not shown.

FIGURE 8. Diversity of Toxicodryas hemipenes. (A) Toxicodryas blandingii from Ivory Coast, in lateral and “front” views, redrawn from figure 29 of Doucet (1963); scale bar = 1 cm, (B) T. pulverulenta from Ivory Coast, redrawn from photograph of Plate IX, photo K of Doucet (1963), who listed the hemipenis length as 16 mm. Drawings by J. Rivera, (C) Photograph in life of male T. vexator sp. nov. (field no. CRT 3890) from Kona, Democratic Republic of the Congo (DRC), showing everted hemipenis in ventrolateral view. Photo: Z. Nagy, (D) Photograph of preserved male T. adamanteus sp. nov. holotype (UTEP 22204) from DRC, showing everted hemipenis in ventrolateral view. Photo: E. Vaughan.

FIGURE 12. Photos of Toxicodryas adamanteus sp. nov. in life. (A and B) adult male holotype (UTEP 22204, SVL = 812 mm) from Npenda, Democratic Republic of the Congo (DRC). Photo: E. Greenbaum, (C) adult female (UTEP 22205) from Salonga National Park, DRC. Photo: E. Greenbaum, (D) adult female (UTEP 22201) from Kihungwe, DRC, with a vespid wasp. Photo: E. Greenbaum, (E) ventral view of adult male (UTEP 22200) from Mayindombe, DRC. Photo: E. Greenbaum, (F) unsexed individual from Banalia, DRC. Photo: K. Mebert, (G) juvenile female (UTEP 22198) from Punia Gorilla Reserve, DRC. Photo: G.M. Mitamba.

FIGURE 13. Photos of the preserved holotype of Toxicodryas adamanteus sp. nov. (UTEP 22204, SVL = 812 mm) from Npenda, Equateur Province, Democratic Republic of the Congo. (A) Entire body in dorsal view, (B) entire body in ventral view including everted hemipenes, (C) head in dorsal view, (D) head in ventral view, (E) head in left lateral view, (F) head in right lateral view. Photos: E. Vaughan.