Rhampholeon tilburyi, Branch, William R., Bayliss, Julian & Tolley, Krystal A., 2014

Branch, William R., Bayliss, Julian & Tolley, Krystal A., 2014, Pygmy chameleons of the Rhampholeon platyceps compex (Squamata: Chamaeleonidae): Description of four new species from isolated ‘ sky islands’ of northern Mozambique, Zootaxa 3814 (1), pp. 1-36 : 25-28

Rhampholeon tilburyi sp. nov.

Mount Namuli Pygmy Chameleon

Synonomy: Rhampholeon platyceps Branch & Ryan 2001 , p 282.

Rhampholeon tilburyi Timberlake et al. 2010 , p57 nomen nudum Rhampholeon nov. sp. ( tilburyi ) Timberlake et al. 2010, p61 nomen nudum Rhampholeon platyceps ( tilburyi ) Timberlake et al. 2010, p61 nomen nudum Rhampholeon Portik et al. 2013, p 416.

Etymology. The specific epithet is a patronym for our good friend Dr. Colin Tilbury for his outstanding contributions to knowledge of African chameleons, most recently exemplified in his magnum opus, the Chameleons of Africa ( Tilbury 2010). For the last 30 years his travels throughout Africa in search of chameleons, combined with his stunning photography, have been a source of inspiration. His studies have done much to enhance our understanding of African chameleons, and it is with great pleasure that we name this chameleon in his honour.

Types. The type series comprises eight specimens, including:

Holotype. An adult female ( PEM R14921; Fig. 8 D) collected by a local guide, 30 November 1998, in the Ukalini Forest that nestles under the south face of the main Namuli peak, Namuli Massif, Zambézia Province, Mozambique (15˚22'S 37˚04'E, ca 1550 m a.s.l.).

Allotype. An adult male ( PEM R17132, Fig. 8 A) with everted hemipenes, collected by K.A. Tolley and S. van Noort, 26 May 2006, at night perched on a dead branch 50 cm above ground in a patch of forest dominated by overgrown tea ( Camellia sinensis ) on the SDZ Cha Sarl Tea Estate at Gurué, Namuli Massif, Zambézia Province, Mozambique (15˚26'51.6”S, 37˚00’,32.6”E, ca 839 m a.s.l.).

Paratypes. Six specimens, comprising two females ( PEM R17134, Fig. 8 B, same collecting details as allotype; PEM R17135, perched on a tea bush in an overgrown patch of tea, on SDZ Cha Sarl Tea Estate at Gurué, 15˚26'42.8”S, 37˚00’,19.2”E); three males ( PEM R17131, SDZ Cha Sarl Tea Estate at Gurué, 15˚26'49”S, 37˚00’,29”E; PEM R17133, same collecting details as allotype; PEM R20372, Muretha Plateau, Namuli Massif, Zambézia Province, Mozambique (15˚23'26”S, 37˚02’,03”E, ca 1804 m a.s.l.), collected by J. Bayliss 27 May 2007; and a very small juvenile ( PEM R20373, same details as previous specimen).

Meristics. Measurements for the type series of Rhampholeon tilburyi sp. nov. are summarized in Table 8 .

Diagnosis. The Mt. Namuli pygmy chameleon is referable to the Rhampholeon (subgenus Rhinodigitum Matthee et al. 2004) by possessing a short hemipenis that is almost bag-like, acalyculate and adorned with a pair of simple apical “horns” with a variable number of thorn-like papillae arranged on the outer aspect of the horn; having an unpigmented parietal peritoneum, claws that are strongly bicuspid, smooth plantar surfaces, a rostral process, and short tail (<27% of total length in adult males). It can be distinguished from most other species in Rhampholeon (Rhinodigitum) by having deep inguinal (absent or indistinct in Rh. boulengeri , Rh. nchisiensis , Rh. uluguruensis , and Rh. moyeri ) and axillary pits (also absent in Rh. nchisiensis ). It differs from Rh. platyceps and Rh. maspictus sp. nov. by its smaller size (<65mm total length) and weak crenulations of dorsal crest. It differs from all other members of the Rh. platyceps complex, including the populations from Mt Mabu, Mt Chiperone and Mt Inago, by retaining in adult males a prominent flexure (>32˚) of the snout in front of the orbit (flat or <10˚ in adult male Rh. platyceps and Rh. maspictus sp. nov.; <18% in the only known adult males of Rh. nebulauctor sp. nov. and Rh. bruessoworum sp. nov.), and a narrower head (HW/HL% 49.4%; 53.2–59.8% in all other species). Finally, the species is also genetically well differentiated from all other Rhampholeon , and all specimens examined form a monophyletic clade from Mt. Namuli.

Description of Holotype. Adult female, viscera exposed by a single ventral incision and two lateral incisions on left flank.

Head: Flattened, with only a small upward flexure of the snout at the front of the orbit (angling upwards at approximately 28˚ from a line between tip of snout and top of casque); casque weak, flat with small, conical tubercular edges; temporal crest moderate, forming a straight ridge of 7 raised, rounded tubercles, 3rd and last largest; lateral crests weak, composed of small conical tubercles that demarcate the edge of the casque; temporal crest moderate with a single row of interrupted large tubercles; parietal crest almost absent, composed of a few enlarged tubercles in the mid-line; supraorbital ridge well marked but without obvious clusters of tubercles (vaguely present at the posterior edge), and with a very small ‘soft horn’ of enlarged tubercles at the junction with the shallow interorbital ridge; interorbital ridge composed of 12 small granular tubercles that demarcate the posterior edge of a prominent frontal depression; two enlarged tubercles on inferior orbital rim; rostral ridges very well marked, and fusing at tip of the snout which bears a rostral process (1.5 mm, in fixation flattened against rostrum), about 7 small granules long and 5-6 granules wide at base; nares opening posterio-ventrally; no gular or mental appendages; scales on throat homogenous, more stellate than those on crown of head and subequal in size to those on the belly.

Body: Dorsal crest weak, composed of a double row of enlarged, rounded tubercles along the backbone; the crest undulates between 13 equally spaced clusters of enlarged, spinose tubercles that are largest on the middle of the body, flatter and smooth over the forelimb and sacral regions, and only vaguely visible on the tail; deep axillary and inguinal pits are present; flank scalation heterogenous, composed of small, stellate granules with scattered, enlarged spinose tubercles, the largest occurring over the shoulder; chest, belly and lower surface of tail smooth; limb scalation more irregular, with numerous larger, spinose tubercles on forearms; soles of feet sub-spinose; claws strongly bicuspid; accessory planter spines at base of claws very small, almost absent; tail gently tapering, dorsoventrally flattened, 21.7% of total length, and covered with homogenous conical tubercles.

Colour in preservative: Body mottled brown with reddish brown reticulation on flanks; head darker above, blotched with dark brown; belly and inner surfaces of limbs paler with darker specking; tail dark brown above and below.

Description of Allotype (as for holotype, unless noted). Adult male, with everted hemipenes and viscera exposed by a single, ragged ventral incision and liver tissue excised for DNA analysis.

Head: A very prominent angular flexure of the snout at the front of the orbit (approx 40˚ from line between tip of snout and casque); supraorbital ridge well marked with clusters of tubercles at posterior and anterior level of orbit, the latter forming a ‘soft horn’ two scales high; rostral ridge fusing anteriorly with an obvious rostral process (1.3 mm), that is rounded in profile and composed of about 6 small granules long and 5-6 granules wide at base.

Body: Claws strongly bicuspid; accessory planter spines at the base of claws weakly developed; tail 24.0% of total length.

Coloration in life ( Fig. 8 A): Head, body and tail tan to brown with orange flush along midflank and greenish flush over back and outer surfaces of hind limbs; two prominent diagonal lines on flanks, formed from three darkish spots joined by grey infusion; belly, throat, inner surfaces of limbs and underside of tail light tan; outer skin of limbs darker brown; snout with wide orange band running diagonally through nostril; skin of orbit and temporal region darker brown with scattered, intense green-blue individual tubercles; iris orange-red.

Coloration after preservation: Body very dark, almost blackish; all normal coloration lost due to fixation in concentrated formalin.

Paratype variation. The tail varies from 18.3–21.7% of total length in females, and from 24.0–25.8% in males; the rostral process varies from 7.9–10.4% of head length in females, and from 15.9–16.6% in males. In life the iris of a male paratype (R17131) was reddish and the snout had an indistinct brown stripe rather than the orange band in the allotype. In addition, a few scattered green-blue tubercles extended onto the snout, as well as on to the orbit and temporal region. Prominent “leaf vein” dark lines on the flank were also well developed.

Size. Largest male—PEM R17132 (allotype) 39.6 + 12.5 = 52.1 mm; largest female—PEM R14921 (holotype) 55.3 + 15.4 = 70.7 mm. The smallest male (SVL 33.2 mm) still has well-developed hemipenes, indicating that it is sexually mature (although testicular activity was not determined).

Sexual Dimorphism. Whilst the type series is limited in number, there are indications of sexual dimorphism. Females grow considerably larger than males, and the three females in the type series have an average SVL of 51.67 mm, compared with only 34.67 mm for the three males. In addition, males have a more angular head shape (slope 39-45˚, Fig 9 B) than females (slope 22-28˚), and also proportionately longer tails and a longer rostral process (see above). However, the small number of specimens precludes statistical confirmation. More subtle difference in scalation details cannot be assessed until larger series are available.

Hemipenis. (based on everted hemipenes of all three males in type series). Hemipenis short with unadorned basal and apical sections, except for a pair of curved horns that emerge prominently from the expanded, flattened crown, and which bear well developed spines on their upper surfaces; the folds of the sulcus spermaticus flare to drain into the flattened apical region.

Distribution. Restricted to the type locality; Mt. Namuli, Zambézia Province, northern Mozambique, in both the evergreen forests on Manho and Ukalini forests on the Muretha Plateau (1804 m a.s.l.) at the base of the main peaks, respectively, and also in fallow areas of tea plantations at lower elevations (838 m a.s.l).

Habitat. The Namuli Massif shows habitat zonation and is surrounded by Brachystegia woodland at the base. Grassland and scrub with forested river valleys cover the slopes, with grassy plateaus and patches of dense moist evergreen forest near the summit ( Fig. 8 E). The largest surviving blocks include the Manho Forest (c.1,000–1,100 ha) and the Ukalini Forest (c.100 ha), the latter lodged against the base of the Namuli dome. Dominant emergent trees include Cryptocarya liebertiana, Faurea wentzeliana and Olea capensis ( Timberlake et al. 2009) . These forests are under high anthropogenic threat as they are cleared for potato cultivation by surrounding rural communities.

The allotype and most paratypes were collected at night on perches from 30-50 cm above ground in forest adjacent to a mountain stream in a fallow areas of an operational tea estate that have overgrown into a forest. Portik et al. (2013) noted that adults and juveniles were found sheltering on branches of small trees or on the fronds of epiphytic ferns within Ukalini Forest. This contrasts with perches heights of 1.3–5 m recorded for Rh. chapmanorum ( Tilbury 1992) .

Reproduction. The female holotype was gravid with seven almost spherical eggs (largest diameter 4.1-4.5 mm, four in the left oviduct and three in the right oviduct) that lack obvious signs of embryonic development.

Diet. The stomach of the holotype contained insect fragments, including coleopteran elytra.

Predation. A small chameleon, possibly referable to this species, was seen being carried by a Crowned Hornbill ( Tockus alboterminatus ) that was flying over the canopy of Ukalini Forest, 29 November 1998 ( Branch & Ryan 2001).

Figures

FIGURE 8. Rhampholeon tiburyi sp. nov.: A—Allotype (PEM R 17132, K. A. Tolley); B—Paratype (PEM R 17134, K Tolley); C—Head of male paratype (PEM R 20372) showing snout flexure; D—Preserved female holotype (PEM R 14921); E—Manho Forest, Mt. Namuli (J. Bayliss).

FIGURE 9. Rhampholeon bruessoworum sp. nov.: A—Holotype; B—Allotype; C—Habitat on Mt. Inago (J. Bayliss).

Tables

TABLE 8. Measurements (mm) for the type series of Rhampholeon tilburyi sp. nov. from Mount Namuli, Mozambique (PEM: Port Elizabeth Museum).

	PEM R14921 Holotype	PEM R17132 Allotype	PEM R17131 Paratype	PEM R17133 Paratype	PEM R17134 Paratype	PEM R17135 Paratype	PEM R20372 Paratype	PEM R20373 Paratype
Sex	F	M	M	M	F	F	M	J
Snout-vent length	55.3	39.6	33.2	34.6	48.8	50	48.8	21.4
Tail length	15.4	12.5	10.5	11.8	10.9	13.8	15.5	7.4
Total length	70.7	52.1	43.7	46.4	59.7	63.8	64.4	28.8
Head length	21.2	12.5	11.0	11.8	15.5	20.8	17.3	8.6
Head width	10.0	7.3	5.5	5.3	9.1	6.4	9.6	4.3
Orbit diameter	5.1	3.2	2.8	3.0	3.9	4.6	4.5	2.4
Snout length	6.4	3.7	3.8	3.9	5.3	5.5	6.0	3.1
Inter-orbital	5.8	4.7	4.5	5.0	5.5	5.8	5.6	3.5
Rostral process	1.8	2.0	1.8	1.9	1.6	1.7	D	0.8
Casque to Eye	10.6	8.1	5.5	7.3	10.5	10.7	10.7	6.5