Rhampholeon monteslunae, Hughes & Behangana & Lukwago & Menegon & Dehling & Wagner & Tilbury & South & Kusamba & Greenbaum, 2024

Hughes, Daniel F., Behangana, Mathias, Lukwago, Wilber, Menegon, Michele, Dehling, J. Maximilian, Wagner, Philipp, Tilbury, Colin R., South, Trisan, Kusamba, Chifundera & Greenbaum, Eli, 2024, Taxonomy of the Rhampholeon boulengeri Complex (Sauria: Chamaeleonidae): Five New Species from Central Africa’s Albertine Rift, Zootaxa 5458 (4), pp. 451-494 : 482-483

Rhampholeon monteslunae sp. nov. Hughes, Behangana, Tilbury, Dehling, Kusamba, and Greenbaum

Mountains of the Moon pygmy chameleon

urn:lsid:zoobank.org:act:9FF3B31F-E75A-414C-9986-E5D367878D43

Synonymy.

Rhampholeon boulengeri — de Witte 1965 (partim), Tilbury & Tolley 2015 (partim), Spawls et al. 2018 (partim), Tilbury 2018 (partim)

Rhampholeon sp. 5 — Hughes et al. 2018

Etymology. The specific epithet is used as a noun in apposition and is derived from the Latin words for mountain, mons, and moon, luna, in reference to the original phrase for the Rwenzori Mountains, montes lunae, or “Mountains of the Moon”, which is the type locality for this species.

Holotype. UTEP 22735 (field no. ELI 2854 ), adult female, UGANDA, Western Region, Rwenzururu sub-region, Kasese District, Rwenzori Mountains National Park , Nyakalengija entrance, 00.36029° N, 30.00922° E, 1942 m elevation, 1 June 2014, collected at night in primary forest about 1 m above the ground by D.F. Hughes, E. Greenbaum, and M. Behangana ( Fig. 14A ).

Paratype (topotype). Same collection details as holotype, three adult males, one adult female, and one juvenile female, UTEP 21389–21390 , 22736–22738 (field nos. ELI 2837–2838 , 2855–2857 ) .

Paratypes. Two adult males, UTEP 21714 , 22733 (field nos. ELI 2851–2852 ), UGANDA, Western Region, Rwenzururu sub-region, Kasese District, Rwenzori Mountains National Park , Nyakalengija entrance, 00.36047° N, 30.00832° E, 1962 m elevation, 1 June 2014, at night in primary forest about 1 m above the ground by D.F. Hughes, E. Greenbaum, and M. Behangana ( Fig. 14C–D ) . One juvenile male, UTEP 22734 (field no. ELI 2853 ), UGANDA, Western Region, Rwenzururu sub-region, Kasese District, Rwenzori Mountains National Park , Nyakalengija entrance, 00.36039° N, 30.00992° E, 1936 m elevation, 1 June 2014, at night in primary forest about 1 m above the ground by D.F. Hughes, E. Greenbaum, and M. Behangana . One adult female, UTEP 22732 (field no. ELI 2828 ), UGANDA, Western Region, Rwenzururu sub-region, Kasese District, near Rwenzori Mountains National Park , Ruboni Village , 00.34972° N, 30.02973° E, 1655 m elevation, 31 May 2014, collected at dusk about 0.5 m above the ground on a shrub in disturbed secondary forest and garden area near Ruboni Community Hotel by D.F. Hughes, E. Greenbaum, and M. Behangana .

Referred specimens. PEM-R 16518 (field no. CT 347), UGANDA, Western Region, Rwenzururu sub-region, Kasese District, Rwenzori Mountains National Park , Musandama (00.73416° N, 30.17361° E, 2360 m elevation) (1 specimen) . UTEP 21710–21711 , 22727 (field nos. ELI 905–907 ), BURUNDI, Bururi Province, Bururi Forest Reserve (03.92857° N, 29.61662° E, 2011 m elevation) (3 specimens) ( Fig. 14E–F ) . UTEP 22728 , 21712 (field nos. ELI 910–911 ), BURUNDI, Bururi Province, Bururi Forest Reserve (03.94446° N, 29.60686° E, 2201 m elevation) (2 specimens) . UTEP 22729–22731 (field nos. ELI 924–926 ), BURUNDI, Bururi Province, Bururi Town (03.93189° N, 29.61846° E, 1935 m elevation) (3 specimens) . UTEP 21713 (field no. CFS 1599g), BURUNDI, Bururi Province, Bururi Forest Reserve, Rurezi River (03.93393° N, 29.61890° E, 1945 m elevation) (1 specimen) .

Diagnosis. Rhampholeon monteslunae sp. nov. is in the subgenus Rhinodigitum because of its distinctly bicuspid claws, prominent rostral process, smooth plantar surfaces, and phylogenetic placement, thus easily distinguishing it from the six species in the other two subgenera (i.e., Rhampholeon and Bicuspis ): R. gorongosae , R. marshalli , R. spectrum , R. spinosus , R. temporalis , and R. viridis . Rhampholeon monteslunae sp. nov. can be distinguished from all other Rhampholeon species by the following combination of traits: (1) lack of prominent mite pockets in the inguinal region distinguishes it from R. beraduccii , R. platyceps , R. chapmanorum , R. maspictus , R. tilburyi , R. bruessoworum , and R. nebulauctor ; (2) presence of prominent mite pockets in the axillary region distinguishes it from R. nchisiensis and R. acuminatus ; (3) distinct supra-orbital and canthal crests distinguishes it from R. hattinghi ; (4) geographic restriction to the Albertine Rift distinguishes it from R. uluguruensis , R. moyeri , R. colemani , R. sabini , R. rubeho , R. nicolai , R. waynelotteri , and R. princeeai ; (5) shorter inter-limb and snout length in males, genetic divergence, and non-overlapping elevational range at parapatric sites distinguishes it from R. boulengeri ; (6) smaller mean body size, shorter mouth and snout lengths, smaller eye diameters, shorter inter-limb lengths, and shorter hind limbs in females distinguishes it from R. nalubaale sp. nov.; (7) slightly shorter inter-limb lengths in males, shorter eye diameter and inter-limb length in females, and shorter snout lengths in both sexes distinguishes it from R. plumptrei sp. nov.; (8) smaller mean body size, shorter snout length, and smaller eye diameter in females, and shorter inter-limb length in both sexes distinguishes it from R. bombayi sp. nov.; (9) smaller inter-limb lengths in both sexes distinguishes it from R. msitugrabensis sp. nov.

Genetic differentiation and variation. A summary of pairwise sequence divergence for three DNA markers (16S, ND2, and RAG-1) among individuals of R. monteslunae sp. nov. and other Rhampholeon species is presented in Supplementary Material 1.

Description of holotype (UTEP 22735). Adult female, SVL 36.7 mm and TL 12.3 mm. Body shape leaf-like. Casque flattened, with short head. Neck indistinct from head. Supra-orbital crests distinct with cluster of tubercles connected by a ridge with 14 tubercles across casque and 19 tubercles from peak-to-peak of crests. Rostral process 1.34 mm, composed of elongated tubercles. Temporal crest discrete with several enlarged tubercles extending posteriorly from mid-eye. Nares open in a posterior orientation. Canthal ridge consists of raised tubercles, one raised higher than others near snout. Eighty-six upper and 82 lower labial tubercles present along tip of snout to rictus of mouth. Body covered in nearly homogenous, flattened tubercles. Several larger conical tubercles present on dorsal flanks around midbody. Weakly crenulated dorsal crest, more prominent near nape. Many enlarged conical tubercles present on limbs. Claws markedly bicuspid.

Coloration of holotype (in life). A photograph of the holotype is presented in Figure 14A . Overall background color tan with patches of light brown, white, and dark brown. Top of head lighter brown. Head has several darker brown tubercles on canthal, orbital, and temporal ridges. Dark brown patch located just below eye towards edge of mouth. Gular region white with some brown patches, which extends from tip of chin to neck region. Two diagonal dark brown lines extend from just posterior to nape, down lateral flanks towards tail, resembling veins of a leaf. Tail a similar brown to tan color as body. Largest body tubercles dark brown to black. Patches of orangish color present on lateral flanks towards venter. Limbs darker brown color than body.

Variation. A summary of descriptive morphometrics for R. monteslunae sp. nov. is presented in Table 4 , comparative boxplots in Figure 4 , and measurements of the type specimens in Table 9 . Photographs displaying color variation in life are presented in Figure 14 . Morphological proportions are generally consistent with those of the holotype. Males have similar body sizes (M: mean 41.1 mm, range 33.4–50.9 mm, n = 8; F: mean 40.4 mm, range 30.4–54.4 mm, n = 10), but longer tails (M: mean 13.8 mm, range 11.9–15.7 mm, n = 8; F: mean 10.9 mm, range 8.2–13.7 mm, n = 10) than females. Body coloration is consistently lighter brown to tan, usually with white hues and two dark brown to reddish lines on the lateral flanks extending diagonally from the dorsal crest toward the hind limbs, resembling veins on a leaf. The color of the legs can sometimes be a much darker brown than the body.

Reproduction. Unknown (but see below). The smallest specimen examined ( UTEP 22736 ) was collected on 1 June 2014 with SVL 30.4 mm and TL 9.3 mm from Rwenzori Mountains National Park , Uganda.

Distribution, natural history, and conservation. Rhampholeon monteslunae sp. nov. is found in montane forests at an elevation range of 1655–2360 m. Most specimens were collected from forest within Rwenzori Mountains National Park, along the route from the Nyakalengija Gate, and a single specimen (PEM-R 16518) from the northern end of the park near Musandama village. One specimen (UTEP 22732) was collected from secondary forest in disturbed vegetation (ca. 0.5 m above ground) in the garden of the Ruboni Community Hotel just outside of Rwenzori Mountains National Park. Another series of specimens were found in Bururi Forest Nature Reserve of southern Burundi, including some from just outside the reserve around the town of Bururi. Extensive mark-recapture chameleon surveys in October 2018 by one of us (DFH) at the type locality detected 17 individuals across seven nights (10 males, 5 females, and 2 juveniles) that were found sleeping at a mean perch height of 627 mm (range 254–1575 mm) and a mean perch diameter of 3.31 mm (range 1.79–4.39 mm). Two of these females were gravid, two individuals were juveniles (SVLs 21.9 mm and 27.3 mm), and only one individual was recaptured across seven consecutive surveys—three nights after its initial capture. This species occurs in a disjunct distribution with relatively low intraspecific genetic diversity between allopatric populations. If populations are not discovered from intervening sites, perhaps there were forested connections that have been lost, or fluctuations in the historical water levels of the crater lakes led to population-level losses, which produced the disjunct distribution currently observed. Other lizard species collected from Rwenzori Mountains National Park included Adolfus jacksoni , Kinyongia carpenteri , K. xenorhina , K. tolleyae , Leptosiaphos meleagris , Trioceros ellioti , T. johnstoni , and T. rudis .

Figures

FIGURE 4. Box plots showing variation in external traits of the Rhampholeon boulengeri complex from the Albertine Rift, Central Africa. Sample sizes for each species are denoted in the bottom right quarter. Males and females are separated to show degree of sexual-size dimorphism across members of the complex. All measurements are in mm. Plots show the median, 1st and 3rd quartiles, minimum and maximum inter-quartile ranges, and outliers. Refer to text for description of the linear measurements.

FIGURE 14. Photographs of various individuals of Rhampholeon monteslunae sp. nov. in life. (A)—Adult female holotype (UTEP 22735) from Rwenzori Mountains National Park, Uganda; (B)—Adult female (uncollected) from Rwenzori Mountains National Park, Uganda; (C)—Adult male (UTEP 21714) from Rwenzori Mountains National Park, Uganda; (D)—Adult male (UTEP 22733) from Rwenzori Mountains National Park, Uganda; (E)—Adult male (UTEP 21711) from Bururi Forest Reserve, Burundi; (F)—Adult male (UTEP 21710) from Bururi Forest Reserve, Burundi; (G)—Habitat view of a riparian area near the main trail at the type locality; (H)—Habitat view of the forest at the type locality.