Research Article |
Corresponding author: Rainer Günther ( rainer.guenther@mfn-berlin.de ) Academic editor: Johannes Penner
© 2016 Rainer Günther, Stephen Richards.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Günther R, Richards S (2016) Description of a striking new Mantophryne species (Amphibia, Anura, Microhylidae) from Woodlark Island, Papua New Guinea. Zoosystematics and Evolution 92(1): 111-118. https://doi.org/10.3897/zse.92.7629
|
We describe a striking new species of the microhylid frog genus Mantophryne from Woodlark Island in Milne Bay Province, Papua New Guinea. It is most similar to M. lateralis but is distinguished from that species by its more slender body, longer shanks, larger discs on the toes, and unique advertisement call. Most known specimens had, in life, a striking golden tan mid-dorsum bordered by broad blackish dorsolateral bands. The new species is currently known only from the rainforests of Woodlark Island, where males call from elevated perches up to 4 m above the ground from climbing Freycinetia plants, from crevices and hollows in elevated limestone outcrops, and from tree buttresses and on top of fallen logs on the forest floor. It is the most arboreal member of this predominantly terrestrial genus discovered to date.
Frog, new species, taxonomy, bioacoustics, New Guinea
The genus name Mantophryne was coined by
In a recent paper
During field work on Woodlark Island, Papua New Guinea (Fig.
Frogs were located at night by tracking their advertisement calls, and all specimens were photographed in life prior to preservation. Tissue probes from liver were taken from two of the three collected specimens and stored in about 96% ethanol to enable DNA sequencing. All specimens were fixed in 10% formalin and later transferred to 75% ethanol for permanent storage. Measurements were taken with a digital calliper (> 10 mm) or with a binocular dissecting microscope fitted with an ocular micrometer (< 10 mm) to the nearest 0.1 mm.
SUL snout-urostyle length: from tip of snout to distal tip of urostyle-bone; SUL is subject to lower measurement error than the traditionally used snout-vent length (SVL) (R. Günther, pers. obs.) so we have used it here. However both measurements are very similar. We therefore directly compare SUL measurements reported here with SVL measurements of congeners presented in the literature;
TL tibia length: external distance between knee and ankle
TaL length of tarsus: external distance between tarsal and ankle joints held at a right angle
T4L length of fourth toe: from tip of toe to proximal end of inner metatarsal tubercle
T4D transverse diameter of disc of fourth toe
F3L length of third finger from tip to proximal margin of central palmar tubercle
F3D transverse diameter of disc of third finger
F1D transverse diameter of disc of first finger
T1D transverse diameter of disc of first toe
HL head length: from tip of snout to posterior margin of tympanum
HW head width, taken in the widest point
SL snout length: from an imaginary line that connects the centres of eyes to tip of snout
END distance from anterior corner of orbital opening to centre of naris
IND internarial distance between centres of external nares
ED eye diameter: from anterior to posterior corner of orbital opening
TyD horizontal diameter of tympanum
Advertisement calls were recorded with a Marantz PMD-660 digital recorder and a Sennheiser ME66 shotgun microphone and analysed with Avisoft-SAS Lab Pro software.
Specimens are stored in the collection of the South
Our information concerning features of Mantophryne species was taken from original descriptions (
The new species is assigned to the genus Mantophryne on the basis of the following characters: body slender, circum-marginal grooves on all finger and toe discs, those on the toes wider than those of fingers; symphygnathine condition of the maxillary bones (anterior processes of the maxillary bones not fused but almost in contact and joined by a ligament); and two protuberances on chin. It differs from all hitherto known congeners by its 1) relatively long legs (TL/SUL 0.55–0.57 vs. <0.51 in males of all congeners;
In life mid-dorsal band and dorsal surfaces of thighs uniform golden tan, dorsal surfaces of shanks yellow, posterior of thighs, extending partly to dorsal surfaces, orange-red; supra-canthal stripe, extending onto upper eyelids, yellowish; dorsolateral band blackish, ventral boundary of this band delineated by narrow white stripe; axillary region yellowish and inguinal region orange-red. Lateral surfaces of shanks and dorsal surfaces of tarsi dark brown, their ventral parts mottled with dark brown. Iris silvery with a few irregular dark lines; anterior and posterior portions of iris more strongly pigmented by dark lines and with an orange hue (Fig.
Colouration of the preserved holotype: Dorsal surfaces of head, shanks and mid-dorsum uniform light grey; dorsal surfaces of thighs with faint brown mottling; those of upper arm more strongly mottled with brown; anterior of lower arm and dorsal surfaces of hands, tarsi and metatarsi irregularly brown; conspicuous large dark brown spots edged with a white line extend to posterior of lower arm and anterior tarsus and metatarsus; a relatively wide whitish supra-canthal stripe extends from snout tip to middle of eyelid. The broad dorsolateral bands begin at the posterior edge of the orbital opening, are widest on middle of flanks, and end with a small tip at cloacal opening. Ground colour of all ventral surfaces is off-white. Mottling is same colour as in life.
Measurements of the holotype are listed in Table
Body measurements and body ratios of the type series of Mantophryne insignis sp. n. Reg-No=registration numbers; FN are the field numbers of Stephen Richards (SJR).
Reg-No FN |
R69237 SJR 13920 |
83181 SJR 13923 |
PNGNM SJR 13932 |
Mean±SD |
---|---|---|---|---|
SUL | 36.2 | 35.0 | 35.4 | 35.5±0.61 |
TL | 20.7 | 19.8 | 19.5 | |
TaL | 12.2 | 12.0 | 11.5 | |
T4L | 20.1 | 19.1 | 18.3 | |
T4D | 1.6 | 1.5 | 1.5 | |
F3L | 10.7 | 9.2 | 9.1 | |
F3D | 1.0 | 1.0 | 1.0 | |
T1D | 1.1 | 1.0 | 1.0 | |
F1D | 0.8 | 0.7 | 0.7 | |
HL | 12.5 | 12.2 | 12.3 | |
HW | 11.8 | 11.5 | 11.6 | |
END | 3.0 | 2.9 | 3.1 | |
IND | 3.5 | 3.2 | 3.4 | |
ED | 3.8 | 4.1 | 4.0 | |
TyD | 2.1 | 2.5 | 2.3 | |
SL | 5.5 | 6.0 | 5.6 | |
TL/SUL | 0.57 | 0.57 | 0.55 | 0.56±0.01 |
TaL/SUL | 0.33 | 0.34 | 0.32 | 0.33±0.01 |
T4L/SUL | 0.56 | 0.55 | 0.52 | 0.54±0.02 |
T4D/SUL | 0.044 | 0.043 | 0.042 | 0.043±0.001 |
F3L/SUL | 0.30 | 0.26 | 0.26 | 0.27±0.02 |
F3D/SUL | 0.022 | 0.029 | 0.028 | 0.026±0.004 |
T4D/F3D | 1.60 | 1.50 | 1.50 | 1.53±0.06 |
F1D/SUL | 0.022 | 0.020 | 0.020 | 0.021±0.001 |
T1D/F1D | 1.38 | 1.43 | 1.43 | 1.41±0.03 |
HL/SUL | 0.35 | 0.35 | 0.35 | 0.35±0.00 |
HW/SUL | 0.33 | 0.33 | 0.33 | 0.33±0.00 |
HL/HW | 1.06 | 1.06 | 1.06 | 1.06±0.00 |
END/IND | 0.86 | 0.91 | 0.91 | 0.89±0.03 |
ED/SUL | 0.105 | 0.117 | 0.113 | 0.112±0.006 |
TyD/SUL | 0.058 | 0.071 | 0.065 | 0.065±0.007 |
TyD/ED | 0.55 | 0.61 | 0.58 | 0.58±0.03 |
SL/SUL | 0.152 | 0.171 | 0.158 | 0.160±0.009 |
Body size (SUL) of three adult males (including the holotype) varied only slightly, from 35.0 mm to 36.2 mm, mean 35.5 mm, SD (standard deviation) 0.61. Measurements of all types are listed in Table
Three additional adult male specimens of this species (
The advertisement call of Mantophryne insignis sp. n., recorded at an air temperature of 25 °C, is a rattle of several seconds duration (Fig.
Two complete calls of the holotype and two calls of SJR 13932 were analysed. Call duration varied from 4.6 to 6.5 s, mean 5.9 s. Number of notes per call was 38–52, mean 47.5. Note repetition rate was from 8.0 to 8.3/s, mean 8.1 notes/s. Mean note duration of two calls from the holotype was 53.1 ms, SD 15.4, range 30–78 ms, n=104; mean internote interval duration was 72.9 ms, SD 12.7, range 41–153 ms, n=102. For technical reasons note and internote length from the calls of the second specimen could not be measured exactly and therefore are not considered here. Note and internote interval length and amplitude of notes clearly increased during the course of the call (compare Figs
In three of the four calls the last internote interval is clearly the longest and in one call the last but one interval was the longest. All notes are composed of pulses, and these mostly cluster into pulse-groups. The first pulse of almost all notes is clearly separated from the following (clustered) pulses. Frequencies scatter mainly from 1.0 to 3.5 kHz with dominant frequency at 2.0 kHz (Fig.
The three type specimens of M. insignis were detected by their calls, which were uttered at night from hidden perches 50–80 cm high in a limestone block, a tree buttress and a fallen log, all in lowland rainforest (30–180 m asl) in south-central Woodlark Island. However two of three additional specimens found calling on Woodlark Island by F. Kraus (pers. comm.) were approximately 4 m above the ground, in climbing pandanus (Freycinetia sp.) plants. The third specimen was calling from under a leaf on the forest floor. The slender body form, long legs and expanded toe discs (relative to congeners) reflect the unusually arboreal habits of this Mantophryne species. Given the uniformity of habitat across the island, and the lack of major topographic relief, it is likely that the species is widespread in lowland rainforest on Woodlark Island. This species has not been reported from any other islands in the region and may be endemic to Woodlark.
The name insignis is derived from the Latin ‘insignis’ meaning remarkable or conspicuous, and refers to the species’ distinctive colour pattern and unusual (for the genus) ecology.
Mantophryne lateralis, which is mainly distributed throughout the lowlands of eastern New Guinea (
With a snout-vent length up to 82 mm Mantophryne louisiadensis is substantially larger than the new species; it also has a broader head, a more robust habitus, lacks dark lateral bands and does not exhibit the striking golden tan middorsal area or clearly delimited brown spots on the abdomen (
Mantophryne axanthogaster male is also larger (> 40 mm SVL) than M. insignis and further differs from the new species by its flecked (vs. uniform golden tan) dorsum, lack of dark lateral bands, and uniform grey venter (vs. strongly spotted). Moreover, its advertisement call contains 13–18 notes (vs. 38–52 notes) with a mean note duration of 126 ms (vs. about 50 ms) and a mean note repetition rate of 1.8 notes/s (vs. 8.1 notes/s) at 26.5 °C (
With a snout-vent length of 25–31 mm Mantophryne menziesi is smaller than the new species, lacks dark lateral bands and a blotched venter, and has a grey- brown (vs. golden tan) dorsum. Its advertisement call is also different, with notes having a length of about 200 ms (temperature not available) (vs. 50 ms). Moreover in M. menziesi the squamosal and frontoparietal bones meet to form an arch over the prootic region, a character which is unique for asterophryine microhylid frogs.
Hylophorbus infulatus (until recently Mantophryne infulata) is similar to M. insignis sp. n. in many body proportions. The species differ, however, in their internarial spacing. The ratio END/IND of 20 specimens of H. infulatus ranges from 0.73–0.84 (
Field work on Woodlark Island was supported by Woodlark Mining Limited and SJR is particularly grateful to George and Eleanor Clapp of WML’s Environment Department for their assistance and support. Francis Crome and Daniel Moriarty also assisted the second author’s work in various ways. The PNG National Research Institute and Department of Environment and Conservation approved the second author’s research visa, and the export of specimens respectively. Carolyn Kovach and Mark Hutchinson provided assistance at the South Australian Museum, and Lisa Capon produced the map. Fred Kraus (University of Michigan) kindly provided field observations on the new species’ habitat use, and a photograph of an additional specimen from Woodlark Island and we are also grateful to Allen Allison (Bishop Museum) who provided some measurements of this material.