Observations on the breeding biology of a microhylid frog (genus Oreophryne) from New Guinea

3 Pages·1993·0.89 MB·English

by  G R Johnston

.
Transactions ofthe Royal Society ofS. Aust. (1993), 117(2). 105-107.
BRIEF COMMUNICATION
OBSERVATIONS ON THE BREEDING BIOLOGY OF A MICROHYLID FROG
(GENUS OREOPHRYNE) FROM NEW GUINEA
Theconquestofterrestrial environments isamajortheme
in vertebrateevolution. Classically the Amphibia have been
viewed as an intermediate stage between the aquatic and
terrestrial groups' 2. However, the standard view of the
amphibian life-cycle involving eggs hatching into aquatic
tadpoles which subsequently metamorphose into terrestrial
frogs belies the true diversity ofreproductive modes in the
Amphibia.
The diversity of reproductive modes is greater among
amphibians than in other vertebrates* All orders of the
.
Amphibia include species which deposit eggs in terrestrial
environments,andterrestrialdevelopmenl hasevolvedseveral
times within the order Anura*
Deposition of eggs out of water is a major step toward
terrestriality amongamphibians. Therefore, itisnotsurprising
that most variation in reproductive modes among anurans
occurs in tropical environments where there are high levels
of atmospheric moisture3 A second major step toward
.
terrestriality occurs in those groups which exhibit direct
development. Theevolutionofdirectdevelopment hasbeen
important inthesuccessful invasionofmontaneenvironments
by amphibians3. Direct development occurs in all
Australopapuan microhylid frogs4.
Despitetheirabundance, littleisknownaboutthebreeding
biologyofNewGuinean mierohylids. Small numbersoflarge,
heavily yolkedeggsareconcealed inleafaxils, hollowstems,
mossclumpsorbeneaththeground4,5. They maybeattended
by anadult frog, usually a male4,5. These frogsgenerallydo
not form breeding aggregations (exceptions may be
Asterophrys turjticula6and Sphenophrynemehelyi1) and may
callspasmodically. Thusanyobservationsarefortuitousand
valuable. Fig. 1. AmaleOreophryne(SAM R40884)attendingaclutch
This notereportsobservationson the reproductivebiology ofeggsontheundersideofaleafnearTabubil, PapuaNew
Guinea.
ofanunidentified speciesofOreophtynenearTabubil inthe
WesternProvinceofPapuaNewGuinea(5°17'S, 14112'E).
This species was assignedto Oreophryneon the basis ofits
partially webbed feel and the presence ofsmall clavicles8 embryos were 3.7-3.8mm long. Each egg contained a very
.
Current confusion surrounding the taxonomy ofthis genus large, ovoid yolk body 3.1-3.2mm in maximum diameter.
prevents reliableallocationofourspecimenstoany particular A single egg from this clutch wasdissected (Fig. 2). The
species. head (l.lxl.lmrn) could be distinguished clearly from the
On theeveningof27.xi.199l asinglespecimen was found laterallycompressedbody, whichwas2.6mmlong. Fourlimb
3.5 kmSSWofTabubil nearasmall creek, beneathaclosed buds were present, although no differentiation ofthedigits
canopy mid-montane rainforest9. At the time ofcollection it was apparent. Posterior to the hindlimb buds the tail was
was sitting over a clutch often eggs on the underside ofa strongly compressed laterally, but no vascularisation was
leaf 0.8m from the edge ofthe creek and 1.5m above the apparent inthepreserved material. Threecephaliclobesand
ground (Fig. 1). It was not heard calling, but its sex was a pair ofpigmented eye spots wereclearly visible. A single
determined laterbydissection. Onlytwootherspeciesoffrog pair of gill buds were present on each side of the head.
wereheardcallingindiearea{Ramigriseaandanundescribed Dorsally,twodarklinesranthelengthofthebody, indicating
member of the Litoria eucnemis species-group). thattheneuralgroovehad notyetclosed. Withtheexception
The clutch was arranged in two vertical lines offour and ofthe presence ofeye pigmentation and the lack of neural
six eggs each. The entire clutch was covered with a thin, grooveclosure, these microhylid embryos resemblestagefive
transparent, membranous structure which yellowed slightly embryos of the South American leptodactylid. Eleuthero-
in alcohol. This layer was quite separate from thejelly-like dactylus coqut
capsule which surrounded the embryos and, although Price.11 illustrated a single, much older embryo of
superficially different, may be homologous to the cord that Oreophrynefrom YapenIsland, IrianJaya. Thetailwasgreatly
joins the eggs of congeners for which the eggs are enlarged and highly vascularised late in development, and
known*'10-11. The capsules were 3.8-4.0mm in diameter, The presumably plays a role in respiratory gas exchange.
,
106
B
Fig. 2. Dorsal (A) and lateral (B) views ofan Oreophryne embryo. Scale bar = 1mm.
Measurements ofthe adult frog were: snout-vent length MalesareknowntoattendeggsintwoPhrynomantisspp.
22.6mm, headlength7.5mm; headwidth7.8mm; eyediameter two Cophixalus spp. and three Sphenophryne spp.3-4- -19
3.1mm; eyetonarisdistance 1.9mm; internarial span 1.8mm; Both malesand femalesattendeggs intwo Oreophrynespp.
tibia length 10.9mm; foot length 14.2mm. The frog and the and one species of Cophixalus10,20 Tyler7 reported
.
clutchitattendedhavebeenregisteredintheSouthAustralian aggregations of Sphenophryne mehelyi attending their
Museum as R40884. individual clutches of eggs. It is not known how long this
Afurthertwo, morphologicallyidentical, maleOreophryne association ofadult frogs with their clutches may last. The
were found calling from a clusteroflarge leaves 3m above association of frogs with their eggs may function in
the ground, 4m from a sago, swamp amongst mid-montane manipulationofeggs,toprovidemoistureforterrestrialeggs,
rainforest6kmSSW ofTabubil atnighton i.xii.1991. Their in protection against predators or for removal of dead or
ccaalslssettweerreecorredceorradneddawniEtlhecatreStOCNonYdePnrsoefresmsiicornoaplhoWnaelEkmCaMn infTehcitsedreepgogrst i.s the first record of any direct developing
Z200. Calls were analysed using ULTRASOUND vl.1013. species laying its eggs on the exposed surface ofa leaf. A
Thecall (Fig. 3)wasabiphasicrattle, beginningwithashort numberofindirectdeveloping frogs fromotherfamiliesare
(0.3-0.4s) seriesofpulsesat 3.2kHz which was followedby known to deposit eggs on vegetation overhanging water in
a longer (0.7-1.0s) series of pulses at the fundamental and the neotropics,22, Africa24, Madasgascar25, the
dominant frequency of2.8kHz, and at 3.2kHz. There were Philippines" and New Guinea"'. In all ofthese species the
26 pulses.s , Eight calls uttered by two individuals gave a hatchingtadpoles fall intothewaterbelow. The Oreophryne
mean call rate ofone per 63s. The call length was 1.0-1.4s we observed breeding in New Guinea were also found in
(mean - 1.1, SD = 0.17). association with water. This may have been an artefact,
The breeding behaviour of thirteen of the 83 species of however, as we concentrated our searches for frogs around
Australopapuan microhylids14,1516'17 has been waterbodiesanddid notsearchthe forestsurroundingthem
documented^10-11'16'18-19-20. Four to 55 eggs are laid11. This as thoroughly.
reduction in clutch size associated with large, yolked eggs This work was funded in part by grants from the Peter
is a common correlate of terrestrial reproduction in Rankin Trust Fund for Herpetology and the James Cook
amphibians21. University. Ok Tedi Mining Ltd, and Phil and Sue Gregory
I07
4 -i assistedwith logisticsupport and transportinNewGuinea.
Ken Sandersonallowedustousehissoftwaretoanalysethe
call. Nelson Kanem assisted in the field. Margaret Davies
l" >! MIl amannduscPraiuplta, ODuermpwsoerky,imnaNdeewhGeulipnfuelaccooulmdmennottshavoenbetehne
!i«f done without the help of Guy Kula (Department for the
Environment,PNG),RosalynBusava(InstituteofPapuaNew
GuineaStudies)andJamesMenzies(UniversityofPapuaNew
Guinea).
-
2
-
1
TT
I I I
2
TIME (seconds)
Fig. 3. Sonagram ofthe call ofan Oreophrync from 6 km
southeast ofTabubil, Papua New Guinea.
'CEavrorloultli,on"R.(FrLe.ema(1n9,88N)ew-VeYrotrekb)r.ate Paleontology and 14GZrwiesisfiettl,,J.R.L.G.(Ed&.),Ty"lBeiro,geMo.grJa.ph(y19a8n2d) epcpo.lo7g5y9-o8f01N,eIwn
2Romer» A. S. (1966) "Vertebrate Paleontology" 3rd Edn _Guinea* (Junk, The Hague).
4ZA(DwUmunepeiihlvfileebmrlisa?ainntR,sy,.oW"Gf..(CME(hc1.iG9cr7&aa2g)wo-TBHVuPilurllee.lsb,s,A,mNLCee.hriw.c(a1YM9gou8or6s)k)..)."NBaito.loHgiysLof14t8h,e *"^ZBB1wu-le2rui0t.mfoe,nl,,P.RT..&.GC..Me&(n1z9Pi9ae0rs)k,eTrrJ,a.nFs.I..(1(R91_8998S)8o)Ac.mAl.Sy.tMeAususs.7t,.No11v21i54t,-.1682379.-5943,.
411-546. 18Mehely, L. von 0901) Termes. Fuzctek 24, 169-271.
-Menzies,J.I.(1976)"HandbookofcommonNewGuinea '^Tylcr, M. J. (1963) Trans. R. Soc. S. Aust. 86, 11-29.
6TSfy.rloegDsro",.nnM(e.WlalJau.n,E(c1po9e6lr7os)g.yTcrIoannmsstm.it.uRt.e1,9S8Wo7ca.u)S.. Aust. 91, 187-190. f'SVSiiaamllto.hnc,,J.SM.L..N.((1&E9d8.D3))u,eBl"elEhvmaoavl.nu,tEicWoo.nla,Er.ySo(cB1ii9o7ob3li)oogplpy..1o24f2,9A-6n21-u46r97,a,nIsn:.
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lamily Microhylidaer(BritishMuseum(Natural History), Missouri Press, Columbia).
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241-273. 23Duellman, W. E. (1970) Monog. Mus. Nat. Hist. Univ.
^Zweifel, R. G. (1956) Amer Mus. Novit. 1766, 1-49. Kansas 1, 1-753.
l"2TWbewen,seDn.d,S.tt(1S9.92&) SSctie.waNret,wMG.uiMn.ea(11988,5)3-7C.opeia 1985. 24D1-r7e0.wes,R. C. (1984)Occ.Pap. CaliforniaAcad. Sci. 139,
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RG.ICR.HAJRODHSN,STZOoNol.ogSychDoeoplaorftmBeionlto,giJcaamleSsciCenocoeks,UFnlivienrdseirtsy,UnTiovewrnssivtiyl,leG,.PQ.lO.dB4o81x1.2100, Adelaide, S. Aust. 5001, andS. J.