Oreophrynella macconnelli Boulenger, 1900

Kok, Philippe J. R., 2009, A new species of Oreophrynella (Anura: Bufonidae) from the Pantepui region of Guyana, with notes on O. macconnelli Boulenger, 1900, Zootaxa 2071, pp. 35-49 : 41-45

Oreophrynella macconnelli Boulenger, 1900

Oreophrynella Macconnelli [sic] Boulenger, 1900: 55 Oreophrynella quelchii macconnelli Rivero, 1961: 175 Oreophrynella macconnelli McDiarmid, 1971: 41

Oreophrynella macconnelli was described by Boulenger (1900) on the basis of a single specimen (a male, although not stated in the description) collected at ca. 1067 m elevation on Mount Roraima , Guyana.

Four specimens (three males, one juvenile) of this poorly known species with characteristic basal webbing on hand and foot ( Fig. 6 A–B) were collected on the southeast slope of Maringma tepui and conform to the holotype and to two topotypic specimens examined. Variation of measurements of the Maringma specimens is given in Table 1 . I refrain from redescribing Oreophrynella macconnelli since a formal redescription of the species is in progress by Means (D. B. Means, pers. comm.).

The following features characterize the Maringma specimens: (1) small size (up to 22.7 mm SVL in male, female unknown); (2) frontoparietal crests indistinct; (3) postorbital crests barely distinct; (4) suborbital crest indistinct; (5) dorsal skin minutely spiculate with scattered small to medium, low, round tubercles; (6) ventral skin coarsely granular; (7) webbing on hand and foot basal; (8) adult dorsal colour in life variable, from light brownish orange to olive brown, with a series of yellow spots forming a dorsolateral line, and series of yellow spots on upper arm and thigh forming short longitudinal lines; (9) adult ventral colour in life creamy yellow with brown marbling; (10) one vocal slit present on the left side of the floor of the buccal cavity.

Colour in life. Adult dorsal colour is variable ( Fig. 7 A–B), ranging from light brownish orange (IRSNB 14333, adult male) to olive brown with darker spotting (IRSNB 14334–5). Olive brown specimens have distinct white spots on the lower flank, while in the orange specimen these spots are yellowish and less conspicuous. All adult specimens with a series of yellow (IRSNB 14333) to brownish orange (IRSNB 14334–5) spots forming a dorsolateral line, and series of similar spots on axilla, upper arm, groin and thigh forming short longitudinal stripes on limbs. All adult specimens have a white to yellow spot below the eye, although this spot is inconspicuous in IRSNB 14333. Adult ventral colour is creamy yellow with brown marbling; palm and sole are orange ( Fig. 7 D). IRSNB 14336, a juvenile, is much darker than adults in having a kaki dorsum with a few yellow spots, and dark brown flanks with a few whitish spots. A few white spots form a less conspicuous dorsolateral line than in adults, and a large longitudinal whitish spot is present on the upper arm and thigh. An anteriorly inclined whitish stripe extends from before the eye to upper lip; white spot below eye smaller than in adults ( Fig. 7 C). Ventral colour similar to adults, but much darker.

Colour in preservative. Dorsal colour ranges from light brown (IRSNB 14333) to dark grey, almost black (IRSNB 14334–6). All spots and stripes are creamy white ( Fig. 8 A). Ventral colour is creamy yellow in adults, dark grey with white spots in the juvenile. Palm and sole are light grey ( Fig. 8 B).

Distribution and ecology. According to Señaris and MacCulloch (2005) and MacCulloch et al. (2007), Oreophrynella macconnelli is reported only from the slopes of Mount Roraima in Guyana and Venezuela, between 1067–1800 m elevation. MacCulloch et al. (2007) considered O. macconnelli a highland species (i.e. typically occurring over 1500 m elevation) with highly restricted distribution.

Specimens from Maringma tepui were collected at 1376 m elevation and expand the known geographic range of the species to the west (roughly 17 km airline, Fig. 4A –B) suggesting a wider distribution than expected. Instead of being a highland species, O. macconnelli appears rather to be an upland species occasionally invading higher elevation areas.

Habitat consists of montane medium-canopy forest with abundant epiphytes and mosses, and rich undergrowth ( Fig. 9 A). All the Maringma specimens were found active by night, walking on the apex of epiphytic ferns ( Campyloneurum sp., Polypodiaceae , Fig 9 B) about 1.0–3.0 m above the ground, except IRSNB 14333 (adult male), which was collected on the ground at 17h00.

When handled specimens exhibited a defensive posture consisting of arching the back and flexing the head downward towards the handler ( Fig. 7 B).

Figures

FIGURE 6. Oreophrynella macconnelli, preserved specimen (IRSNB 14335, 22.3 mm SVL, ventral view). A: Left hand. B: Left foot. Scale bars are 1 mm.

FIGURE 7. Oreophrynella macconnelli. A: Dorsolateral view of IRSNB 14333 (adult male, 22.7 mm SVL) in life. B: Dorsolateral view of IRSNB 14334 (adult male, 22.2 mm SVL) in life. C: Dorsolateral view of IRSNB 14336 (juvenile, 12.3 mm SVL) in life. D: Ventral view of IRSNB 14334 (adult male, 22.2 mm SVL) in life.

FIGURE 8. Oreophrynella macconnelli, preserved specimens. A: Upper row, from left to right, dorsal view of IRSNB 14333 (adult male, 22.7 mm SVL) and IRSNB 14334 (adult male, 22.2 mm SVL); lower row, from left to right, dorsal view of IRSNB 14335 (adult male, 22.3 mm SVL) and IRSNB 14336 (juvenile, 12.3 mm SVL). B: Ventral views of the same specimens as above, respectively.

FIGURE 9. Habitat of Oreophrynella macconnelli on the southeast slope of Maringma tepui. A: Montane mediumcanopy forest with abundant epiphytes and mosses, and rich undergrowth. B: Campyloneurum sp., Polypodiaceae, an epiphytic fern species on which most specimens of O. macconnelli specimens were collected (white arrow indicates typical location of a specimen).

FIGURE 4. A: Map of the Guiana Shield, dark arrow indicates location of Maringma tepui (in red). B: Area map of Maringma tepui showing the type locality of Oreophrynella seegobini sp. nov. (brown dot) and the collecting locality of O. macconnelli (orange dot). Coordinates and boundary with Brazil are approximate and based on the available map (note that there is a substantial difference in the country boundary between this map and that shown in Google Earth). Maps elaborated after “ Roraima Sheet 40 SE ” published by the Survey Department of Guyana, 1972, and a radar image of South America by NASA / JPL / NIMA available at http: // photojournal. jpl. nasa. gov / catalog / PIA 03388.

Tables

TABLE 1. Morphometric measurements (in mm) of Oreophrynella macconnelli specimens from Maringma tepui. Abbreviations are defined in the text. Mean ± SD are followed by the range in parentheses.

Character	Males (n = 3)	Juvenile (n = 1)
SVL	22.4 ± 0.27 (22.2–22.7)	12.3
HL	7.7 ± 0.23 (7.4–7.8)	4.5
HW	8.27 ± 0.35 (7.9–8.6)	4.8
SL	3.5 ± 0.10 (3.4–3.6)	2.0
EN	2.1 ± 0.10 (2.0–2.2)	1.1
EYE	2.6 ± 0.06 (2.5–2.6)	1.7
IND	2.33 ± 0.15 (2.2–2.5)	1.4
IOD	3.13 ± 0.12 (3.0–3.2)	2.1
HAND	5.5 ± 0.10 (5.4–5.6)	3.0
FEM	9.03 ± 0.23 (8.9–9.3)	5.4
TIB	8.53 ± 0.23 (8.4–8.8)	5.0
FOOT	6.83 ± 0.41 (6.4–7.2)	3.6