Colostethus kaiei Kok, Sambhu, Roopsind, Lenglet & Bourne, 2006, sp. nov.
Creators: name: Kok, Philippe J. R.
name: Sambhu, Hemchandranauth
name: Roopsind, Indranee
name: Lenglet, Georges L.
name: Bourne, Godfrey R.
Publisher: name: Zenodo
Year: 2006
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Amphibia
Anura
Dendrobatidae
Colostethus
Colostethus kaiei

description: Colostethus kaiei sp. nov.
Figs 1–8
Material
Holotype. IRSNB 1938 (field no. PK1159), an adult male, collected by Philippe J. R. Kok, Hemchandranauth Sambhu and Indranee Roopsind, 5 December 2005, Kaieteur National Park, along Tukeit trail, Guyana, 5°11’06” N, 59°28’51” W, elevation ca. 400 m.
Paratypes (26 specimens). IRSNB 1939 (female), collected by P. J. R. Kok and D. Arjoon, 22 June 2004, on Muri Muri trail, Kaieteur National Park; IRSNB 1940 (female), IRSNB 1941 (male), collected by P. J. R. Kok and D. Arjoon, 22 June 2004, along Tukeit trail, Kaieteur National Park; IRSNB 1942 (juvenile) collected by P. J. R. Kok and D. Arjoon, 24 June 2004, along Tukeit trail, Kaieteur National Park; IRSNB 1943 (juvenile) collected by P. J. R. Kok and D. Arjoon, in mist forest along the Kaieteur gorge, Kaieteur National Park; IRSNB 1944 (juvenile), collected by D. Arjoon, 28 June 2004, in Archer Simon backdam, Kaieteur National Park; IRSNB 1945 (female), collected by D. Arjoon, 9 July 2004, on Muri Muri trail, Kaieteur National Park; IRSNB 1946–47 (males), collected by P. Benjamin, 15 July 2004, on Muri Muri trail, Kaieteur National Park; IRSNB 1948 (male), collected by D. Arjoon, 19 July 2004, next to the rangers house, Kaieteur National Park; IRSNB 1949 (female), collected by D. Arjoon, 25 July 2004, at the savannah edge, Kaieteur plateau, Kaieteur National Park; IRSNB 1950 (female), collected by P. J. R. Kok, H. Sambhu, F. Marco and R. Williams, 20 November 2004, along Tukeit trail, Kaieteur National Park; IRSNB 1951 (male), collected by P. J. R. Kok, H. Sambhu, F. Marco and R. Williams, 21 November 2004, on the trail across from Menzies Landing, on the right bank of the Potaro River, Kaieteur National Park; IRSNB 1952­54 (females), collected by P. J. R. Kok, H. Sambhu and F. Marco, 4 December 2005, on the left edge of the Kaieteur gorge, Kaieteur National Park; IRSNB 1955 (male), collected by P. J. R. Kok, H. Sambhu, I. Roopsind and F. Marco, 12 December 2005, along Tukeit trail, Kaieteur National Park; IRSNB 1956­57 (males), IRSNB 1958 (female), IRSNB 1959­60 (males), collected by P. J. R. Kok, H. Sambhu, I. Roopsind and F. Marco, 5 December 2005, along Tukeit trail, Kaieteur National Park; IRSNB 1961­62 (females), collected by H. Sambhu and I. Roopsind, 7 December 2005, along Tukeit trail, Kaieteur National Park; IRSNB 1963 (male), collected by H. Sambhu and I. Roopsind, 10 December 2005, along Tukeit trail, Kaieteur National Park; IRSNB 1964 (male) collected by F. Marco and J. L. Talley, 6 December 2005, in disturbed forest adjacent to Menzies Landing, Kaieteur National Park.
Etymology
The new species is named in honour of Kaie, a great Chieftain of the Patamona tribe, from whom Kaieteur Falls was named. According to the legend, Kaie, in order to save his people from being destroyed by a warrior tribe, the Caribs, sacrificed himself to the Great Spirit Makonaima by canoeing over the Falls.
Adult definition and diagnosis
A small species of Colostethus (males to 18.9 mm SVL, females to 19.8 mm SVL); body robust; Finger I and II equal in length when fingers appressed; Finger IV length reaching distal subarticular tubercle on Finger III when fingers appressed; distal tubercle on Finger IV; all fingers slightly swollen in adult males; moderate webbing between Toes I–IV; lateral fringes on fingers present; throat in adult males light greyish pink with discrete dark spotting to extensive stippling extending to chest and venter (however, the throat is never totally grey nor solid black), throat in females immaculate yellow; belly in males whitish with minute dark stippling, belly in females orangish yellow, free of melanophores; dorsolateral stripe present, sometimes barely visible; oblique lateral stripe absent; ventrolateral stripe absent; median lingual process present; cloacal tubercles absent; black arm­band absent in males; testis white (unpigmented) in adult males.
When compared to congeners from the Guiana Shield region, Colostethus kaiei is easily distinguished from C. brunneus (fide Cope 1887), C. fuliginosus Jiménez de la Espada, 1871, C. sumtuosus Morales, “2000” [2002], and C. undulatus Myers & Donnelly, 2001 by the presence of a median lingual process (absent in C. brunneus, C. fuliginosus, C. sumtuosus, and C. undulatus). Colostethus kaiei differs from C. ayarzaguenai La Marca, “1996” [1997], C. guanayensis La Marca, “1996” [1997], C. parimae La Marca, “1996” [1997], C. parkerae Meinhardt & Parmelee, 1996, C. shrevei Rivero, 1961, C. tamacuarensis Myers & Donnelly 1997, and C. tepuyensis La Marca, “1996” [1997] by adult size (adult SVL <20 mm in C. kaiei versus> 20 mm in C. ayarzaguenai, C. guanayensis, C. parimae, C. parkerae C. shrevei, C. tamacuarensis, and C. tepuyensis); from C. murisipanensis La Marca, “1996” [1997], C. praderoi La Marca, “1996” [1997], C. roraima La Marca, “1996” [1997], and C. wothuja Barrio­Amorós, Fuentes & Rivas, 2004 in having dorsolateral stripes (absent in C. murisipanensis, C. praderoi, C. roraima and C. wothuja); from C. sanmartini Rivero, Langone & Prigioni, 1986 in having a smooth dorsum (granular in C. sanmartini), Fingers I and II equal in length when appressed (Finger I shorter than II in C. sanmartini), and in having fringes on fingers (absent in C. sanmartini); from C. breweri Barrio­Amorós, 2006 and C. triunfo Barrio­ Amorós, Fuentes & Rivas, 2004 in having fringes on fingers (absent in C. breweri and C. triunfo); from C. degranvillei Lescure, 1975 in having a light venter (venter dark stippled with white in C. degranvillei), from C. beebei (Noble, 1923) in having Fingers I and II equal in length when appressed (Finger I shorter than II in C. beebei), light pink throat stippled with melanophores in males (immaculate yellow in C. beebei), and in having a smooth dorsum (granular in C. beebei); and from C. baeobatrachus Boistel & de Massary, 1999 and C. stepheni Martins, 1989 in having Finger III not distinctly swollen in males (distinctly swollen in C. baeobatrachus and C. stepheni), and Fingers I and II equal in length when appressed (Finger I longer than II in C. baeobatrachus and C. stepheni).
Measurements (mm) of the holotype
SVL 16.5, HL 5.5, HW 5.4, SL 2.9, EN 1.7, IN 2.3, EL 2.4, IO 2.3, TYM 1.0, FAL 3.8, HAND 4.6, WFD 0.7, TL 8.8, FL 7.3, WTD 0.7.
Description of the holotype
An adult male 16.5 mm SVL; body robust; head slightly longer than wide, head width 98.2% length; head length 33.3% SVL; snout broadly rounded to nearly truncate in dorsal view, acutely rounded in lateral view, extending past lower jaw, snout 52.7% head length. Nares located laterally, opening posterolaterally; canthus rostralis rounded, loreal region feebly concave (nearly flat); internarial distance 42.6% head width; eye­naris distance 30.9% head length, 70.8% eye length. Tympanum nearly round, directed posterolaterally, 41.7% of eye length; separated from eye by a distance equal to 30% of tympanum diameter; supratympanic fold absent; tympanic annulus visible; posterodorsal aspect of tympanum barely visible; anteroventral margin of tympanum distinct.
Tongue attached anteriorly, longer than wide, broadly rounded posteriorly, median lingual process present (Figs 1–2). Choanae circular, lateral. Vocal slits long, lateral. Small teeth present on maxillary and premaxillary, prevomerine teeth absent. Cloacal tubercles absent; vent at level of upper thighs; a small anal flap above vent.
Skin on dorsum and belly smooth.
Forelimb slender, skin smooth; metacarpal ridge absent; hand length 27.9% SVL; Finger I and Finger II equal in length when fingers appressed; rudimentary webbing between Fingers II and III, lateral fringes present on pre­ and postaxial edges of all fingers; Finger III not swollen but all fingers slightly swollen when compared with those of females; Finger IV reaching distal subarticular tubercle on Finger III when fingers appressed; terminal discs expanded, wider than long, about 1.5X width of digit; width of disc on Finger III 0.70; discs with distinct dorsal scutes. Relative lengths of appressed fingers III> IV> II = I; palmar tubercle large, ovoid, 0.85 in diameter, 15.5% HL; thenar tubercle small, elliptic, half the size of palmar tubercle, well separated from palmar tubercle. One subarticular tubercle present on Fingers I and II; two subarticular tubercles on Finger III and IV; basal subarticular tubercles on Fingers I, II, and III largest, subequal, basal and distal subarticular tubercle on Finger IV smaller, subequal; distal tubercle on Finger III very small, inconspicuous (Fig. 3).
Hindlimb robust, skin granular; tibia length 53.3% SVL; heels touching each other but not overlapping when hindlimbs are flexed at right angles to sagittal plane of body; foot length 44.2% SVL; relative length of appressed toes IV> III> V> II> I; Toe I very short, reaching the base of subarticular tubercle on Toe II when toes appressed; discs on toes larger than width of toes; disc on Toe I only slightly larger than width of digit. Size of disc on Toe IV 0.70. Feet moderately webbed, webbing present between toes I–IV, webbing with melanophores; lateral fringes present on all toes but very weak on the postaxial edge of Toe IV. Toe webbing formula I 1­2 ­ II 1 ½­3+ III 2 ¾ ­3+ IV. One to three subarticular tubercles on toes as follows: one on toes I and II, two on toes III and V, and three on toe IV (distal tubercle poorly defined). Inner metatarsal tubercle elliptical, 0.84 in length, outer metatarsal tubercle round, very protuberant, 0.40 in diameter, entirely pigmented. Tarsal keel well defined, tubercle­like and strongly curved at proximal end, extending distally to the fringe on preaxial edge of Toe I. Metatarsal fold strong (Fig. 3).
Colour of holotype in life
Dorsal ground colour medium brown. A wide black band extending from tip of snout laterally around the body and above the vent, containing most of the tympanum and tapering posteriorly from axilla; a thin, white, partly broken dorsolateral stripe above this band, extending from posterior edge of orbit to vent. Upper lip bar dirty white with a few white and light blue dots. Flank same colour as upper lip. Chin same colour as upper lip; throat and chest medium pink, belly cream stippled with melanophores; underside of thigh and shank creamy yellow. Iris metallic reddish bronze.
Upper arm and forearm orange, posterior edge of the latter with a black longitudinal stripe tapering from wrist to elbow. Dark spot on upper surface of wrist. Dorsal surfaces of thigh, shank and tarsus same colour as dorsum, with ill­defined black crossbars, more crossbars on tarsus. Pale paracloacal mark. Toes and digits with small light blue dots. Palms and soles black (Fig. 4).
Colour of holotype in preservative
After two months in preservative, the dorsal ground colour became greyish brown; flanks and upper lips became pale grey; the orange and yellow colouration disappeared and ventral surfaces are white; all black bands and spots remain visible.
Male secondary sexual characters
Males are slightly smaller than females (maximum SVL in males 18.9 mm; maximum SVL in females 19.8 mm), with a cream belly (orangish yellow in females) and a light pink throat stippled with melanophores (throat immaculate orangish yellow in females). Under surface of arms and legs and posterior venter are creamy yellow in males, orange in females. Upper surface of hand is yellow in females, grey in males. In males, throat spotting varies from a few scattered tiny dots to extensive stippling extending to chest and venter, but the throat is never deep grey nor solid black (Fig. 5).
Variation among type specimens
Measurements (range, mean, and standard deviation) of the type series are provided in Table 1. Intraspecific variation is high and adult dorsal colouration varies from medium to reddish brown. Some specimens have small darker blotches on dorsum. Flanks can be yellow or grey. Light blue or white dots on flanks may be absent or present. The dorsolateral stripe is sometimes broken and/or very narrow, but always originates from posterior corner of eye. The width of the lateral black band is also variable; in some individuals it is twice the width found in other specimens. Additionally, overall colouration may vary with light intensity and time of day. The black crossbars on thigh, shank and tarsus may be nearly absent or broken into blotches in some individuals. The iris can be completely red (Fig. 6). In preservative, the dorsal colouration varies from brown to grey, apparently depending on the time spent in preservative. Other changes are similar than those observed in the holotype.
Tadpole definition and diagnosis
A Type 4 tadpole (Orton 1953), exotrophic, benthic type (Altig & Johnston 1989). Size small, up to 16.7 mm TL in stage 27. Tail length 59–64% TL, caudal musculature robust, terminating anterior to tail tip, oral disc emarginate, LTRF 2(2)/3, body dark with minute pale dots, venter transparent.
In being exotrophic and in having keratinized and typical oral structures, the tadpole of C. kaiei is readily distinguished from those of C. degranvillei and C. stepheni (these tadpoles are endotrophic and lack keratinized and typical oral structures [Lescure 1984, Juncá et al. 1994]). When compared to other congeneric tadpoles from the Guiana Shield region, C. kaiei differs from C. beebei by its dark colouration, smaller size and terrestrial habitat (C. beebei tadpoles are yellow, larger and “arboreal”); from C. parkerae in position of nares (naris­snout distance 1.3X eye­naris distance in C. kaiei, 0.5X in C. parkerae); from C. tamacuarensis by the number and size of marginal papillae (papillae smaller and much more numerous in C. tamacuarensis); from C. undulatus by the height of tail (23% of total length in C. undulatus, 17% in C. kaiei), C. undulatus further differs in having smaller jaw sheaths and a less robust caudal musculature; and from C. wothuja by LTRF formula [2(2)/ 3 in C. kaiei, 2(2)/3(1) in C. wothuja].
Tadpole description
Twenty­four larvae were collected: five individuals in Stage 25, eight individuals in Stage 26 and 11 individuals in stage 27. Two stage­ 25 larvae were reared to stage 26 and 27, and two stage­ 26 larvae were reared to stage 28 before preservation. The following is a description of IRSNB 13767, a specimen collected in stage 25 and raised to stage 27: total length 16.7, body length 6.2, tail length 10.5 (63% total length), body width 4.1, body height 2.8 (68% body width), head width at level of eyes 3.8 (93% body width), tail muscle height at base of tail 1.5, tail muscle width at base of tail 1.3, maximum height of tail 2.9, dorsal fin equal in height to ventral fin, greatest fin height 0.9, eye­naris distance 0.6, naris­snout 0.8, internarial distance 9.5, interorbital distance 1.1, eye diameter 0.6, vent tube length 0.95, limb bud length 0.5.
Snout round in dorsal and lateral profiles, nares directed anterolaterally, eyes dorsal, directed anterolaterally. Spiracle sinistral, a short tube, directed dorsolaterally, its base located 30% of body length from snout and 14% of body height from venter. Vent tube distinct, dextral.
Tail musculature highest at body/tail junction, tapering posteriorly, terminating anterior to tail tip. Tail tip rounded. Upper fin originates at junction of body and tail (Fig. 7).
Mouth ventral, oral disc emarginate, width about 1 mm. Labial teeth short, strongly curved, each with at least 15 cusps. LTRF 2(2)/3. A­1 slightly longer than A­2, P­3 slightly subequal to P­2 and P­1. Papillae in a single row, a wide medial gap in upper labium. Papillae tapered, blunt­tipped. Jaw sheaths large, serrate; each side of upper sheath sigmoid, lower sheath V­shaped (Fig. 8).
Va r i a t i o n
Variation of 15 meristic characters from tadpoles in stage 25–28 is given in Table 2. No remarkable differences are noted among larvae from our sample except that tooth row P­3 is usually shorter in larger tadpoles.
Colour in life
Body and top of head dark brown (almost black) with minute light dots. Lateral head light purple (transparent but appearing purple due to blood vessels visible through the skin), with minute darker dots. Caudal musculature grey, heavily mottled with dark brown. Fins transparent, upper fin mottled with dark brown, lower fin free of melanophores. After two months in preservative the light purple disappears and the body colouration remains dark brown, or light brown in specimens left a few days exposed to the light. No other noticeable change occurs.
Vocalizations
Quantitative measures of the somewhat cricket­like chirps of eight males including the holotype [IRSNB 1938; Fig. 9 (a)], paratype IRSNB 1959 and paratype IRSNB 1964 [Fig. 9 (b)] indicated low variation among individuals (mean ± 1SE) for fundamental frequency (4.85 ± 0.40 kHz), harmonic frequency I (9.77 ± 0.30 kHz), harmonic frequency II (14.68 ± 0.07 kHz), and harmonic frequency III (19.59 ± 0.05 kHz) ­ unfortunately the harmonic frequencies while obvious in the original Canary generated sonograms, are not evident in Fig. 9 a, b — note duration (31.69 ± 1.17 ms), intranote duration (106.92 ± 2.41 ms), and internote duration (923.15 ± 34.07 ms; Fig. 9 a, b). The mean number of calls produced per 1­minute section was 74 and ranged from 49 to 101.
Relationships
Colostethus kaiei shares some phenotypic characters with most Guiana Shield Colostethus, like the median lingual process (MLP) (which is quite variable in size and shape among the species), toe webbing (extensive in some species) and robust body (Colostethus species without MLP have slender bodies). As pointed out by Barrio­Amorós (2006) we can assume that all the species having a MLP form a monophyletic group, but contrary to his assertions our recent discoveries show that not all of the species having a MLP share the oblique lateral stripe (absent in C. kaiei, but also in C. parkerae after original description) and the absence of dorsolateral stripes (present at least in C. kaiei, C. beebei and C. sp1 from Paramakatoi, the latter having a broad dorsolateral stripe).
Natural history
Colostethus kaiei is a diurnal, terrestrial, cryptically coloured species mostly found in primary forest where it can be locally abundant. A few specimens were collected in disturbed forest and one specimen was collected at the savannah edge. The species is not closely associated with bodies of water and all specimens were observed far from any stream or pond. Males are territorial and were observed calling from brown dead leaves accumulated at the base of spiny terrestrial bromeliads Aechmea rubiginosa Mez (Fig. 10) but also from over and under dead leaves on the ground. Some males were observed calling from elevated sites such as boulders (up to 120 cm high). Calling activity is mainly restricted to the morning and after rains. We have so far been unable to observe courtship, and still do not know anything about the characteristics of ovipostion sites, but we observed complex maternal care.
Maternal behaviour was a serendipitous discovery ­ in order to detect the presence of amphibians and reptiles along Tukeit trail, a series of 10 pitfalls (plastic buckets of about 28 cm diameter at the top, 30 cm deep) were installed beneath a thirty meters sheet­plastic drift fence along the trail (Fig. 11). Specimens of Colostethus kaiei were commonly observed along the fence, apparently visiting the pitfalls on regular basis. Several specimens (both males and females) were collected along the fence during our daily inspections. Some others were collected into pitfalls from where they were able to escape easily by jumping. On 12 July 2005 at about 10:40 h, two of us (HS and IR) went to inspect the pitfalls. It had rained heavily the previous night and intermittently during that morning. The forest soil (white sand) was saturated, and as a result some pitfalls were half filled, the water entering the traps through the small holes made in the bottom of the buckets. At pitfall 2 (half filled with water) we observed a female Colostethus kaiei that was not driven off by our presence (Fig. 12). The usual behaviour of these frogs in human presence is to quickly escape when disturbed. This behaviour led us to sit down and further observe the frog. During a 30 minutes observation period, the frog was observed jumping into and out of the bucket, and moving along the fence ­ but not travelling more than 20 cm from the bucket before returning and entering the bucket. After about 45 minutes the female suddenly moved to the rim of the bucket (ca. 15 cm from the water), her cloaca facing the bottom of the bucket, and laid a single egg into the bucket. The female had her mouth slightly open during the laying process. The frog was immediately collected and six tadpoles in stage 25 were discovered and collected in the pitfall. Two of them were immediately preserved while the four others were kept in a small glass container to obtain later stages. The next day, we observed another female in pitfall 4, which still contained about 2 cm water. This female was video taped for about 20 minutes hopping around the bottom of the bucket, exiting the bucket and returning, but she finally escaped without showing any particular behaviour. No tadpole was found in the bucket.
Considerable time was devoted to finding natural tadpole deposition sites. We carefully checked small terrestrial bromeliads without any success, but we quickly found four additional tadpoles in stage 27 in a very small pool measuring 39 cm x 43 cm x 6 cm (maximum) deep, between roots at the base of a tree (Fig. 13). Two of these tadpoles were immediately preserved. Two other tadpoles in stage 27 were collected in another small pool adjacent to the first one, and these were immediately preserved. Two small egg masses from a still unidentified, presumably hylid frog, were also observed in the same pool. These two pools were full of dead leaves and detritus. Still investigating the surrounding forest, we found a large egg (about 4 mm diameter), apparently unfertilized, in a third small pool between rocks. This egg that we attribute to C. kaiei was collected and brought back to the base camp to be deposited with the tadpoles in one of the small glass containers. On 9 December 2005, PJRK observed a tadpole vigorously pushing its head inside the egg, apparently feeding on it. Some other tadpoles were kept separately in another container without any egg provisioning but with a dead insect and some detritus found in the pitfall in which the tadpoles were collected. Cannibalism was not observed and all specimens kept in captivity survived. At the end of the field trip, after 8 days of captivity, we did not notice any significant difference in the size of these tadpoles compared to the tadpoles provisioned with egg. This suggests non­obligatory oophagy. The amount of available food found with tadpoles in the small pools also advocates this hypothesis. Direct examination of gut contents of two tadpoles indicate that larvae mainly feed on detritus. We speculate that the supplementary amount of protein brought by trophic eggs could speed up the development of tadpoles that must survive in small, hostile environment commonly visited by predators, and probably prone to desiccation. This egg provisioning could also help to avoid intraspecific cannibalism among tadpoles. It should be noted that unidentified crabs (family Pseudothelphusidae?) were commonly encountered in the buckets filled with water, but also in small natural pools, and are probably preying on tadpoles as they do to the sympatric Colostethus beebei (Bourne et al. 2001, Kok et al. 2005). These crabs seem to be conspecific with the species feeding on adults and tadpoles of C. beebei.
On 11 December 2005 around 13:00 h, on Tukeit trail approximately midway between the airstrip and Tukeit, we collected a male Colostethus kaiei carrying a single tadpole on his back. Unfortunately, the tadpole was lost in one of the several small rocky pools in which the male jumped, but the frog was collected and sex was confirmed by dissection.
Up to 8 tadpoles were collected in a single pitfall but it is not known if all of them come from the same parents or if different males deposit tadpoles in the same pool.
Further investigations are planned to better understand the reproductive ecology of this interesting little frog and will be the subject of future work (Kok et al. in progress).
Distribution
Colostethus kaiei is known only from Kaieteur National Park, Guyana, where it is known to occur in primary and disturbed forest at elevations between 150 and 450 m (Fig. 14). The species is locally abundant, especially along the Tukeit trail. Kok (2005) described the habitat types at this locality in detail.
description: Published as part of Kok, Philippe J. R., Sambhu, Hemchandranauth, Roopsind, Indranee, Lenglet, Georges L. & Bourne, Godfrey R., 2006, A new species of Colostethus (Anura: Dendrobatidae) with maternal care from Kaieteur National Park, Guyana, pp. 35-61 in Zootaxa 1238 on pages 38-56, DOI: 10.5281/zenodo.172836