A new species of laughingthrush (Passeriformes: Garrulacinae) from the Central Highlands of Vietnam

14 Pages·2001·6.2 MB·English

by  Jonathan C Eames

&
Jonathan C. Eames Charles Eames 10 Bull. B.O.C. 2001 121(1)
A new species of Laughingthrush
(Passeriformes: Garrulacinae) from the Central
Highlands ofVietnam
&
byJonathan C. Eames Charles Eames
Received21September2000
Mount KonKa Kinh (14°19'N, 108°24'E) at 1,748 m is the highestpoint in Gia Lai
provinceandoneofthehighestmountainsintheCentralHighlands(CentralHighlands
issynonomouswithWesternHighlands,whichisaliteraltranslationoftheVietnamese
Taynguyen). Central Highlands is itselfa misnomer, since the area is composed of
twoisolatedmassifsbetweenwhichliesaninclinedplateau, whichformspartofthe
Mekongbasin.TothenorthliestheKonTurnplateauwhichextendsacrossc. 10,000
km2 in Kon Turn and Gia Lai provinces, and includes Mount Ngoc Linh, which at
2,598 m is the second highest mountain in Vietnam. To the south lies the Da Lat
plateau,whichextendsacrossapproximately6,000km2,thehighestpointofwhichis
theoutlyingMountChuYangSin(2,244m).MountKonKaKinhislocatedinKonKa
KinhNatureReserve,inthesouthernpartoftheKonTurnplateauandlies95kmfrom
MountNgoc Linh, which is located within the two adjoining sectors ofNgoc Linh
NatureReserve(Figs. 1 and2).
Fromthegeographicalisolationofthemountain, itsheightandthelackofearlier
ornithological exploration,weexpectedtomake interestingfindingsonMountKon
KaKinh. Itwas therefore selected forsurveyaspartofanongoingprojectbetween
BirdLife International andtheForest Inventory andPlanning Institute (FIPI) which
aims to ensure that all internationally important areas forbiodiversity conservation
are included within the revised system ofprotected areas ofVietnam (Wege et al.
1999).
AlongthesummitridgeofMountKonKaKinhon 1 April 1999,JCEmist-netted
andcollectedanunfamiliarlaughingthrushGarrulaxsp. SubsequentlyJCEcollected
afledgedjuvenileon23Aprilandmist-nettedanotheradulton29Aprilfromdifferent
sites at the same locality. Examination of holotypes of four races of Garrulax
G
rufogularis(G. r. assamensis, G. r. intensior, G. r. occidentalisand r rufiberbis)in
theAmericanMuseumofNatural History,NewYork, andcomparisonwith skinsof
G G G
six races of rufogularis (G. r. rufogularis, r. assamensis, G. r. intensior, r.
G G G
occidentalis, r. rufiberbisand r rufitinctus), G. cineraceusand lunulatusat
The Natural History Museum, Tring, U.K., showed that this bird represents a new
distinctivetaxonofGarrulax,whichwename:
Chestnut-earedLaughingthrush
Garrulaxkonkakinhensis sp.nov.
,
Holotype. DepositedattheNaturalHistoryMuseum,Tring(BMNHNo. 1999.31.1),
adult male (gonad condition not noted) collected on Mount Kon Ka Kinh
;
& HOC
Jonathan C. Eames Charles li Hull. 2001 121(1 )
(14 1PNJos :4'j >,Gial aiP>™ince,Vietnam,atc. 1,700masl.on I April 19991Plate I
Figs. 3a-d).
Diagnosis. Garrulax konkakinhensis has four unique plumage features that are not
G G
shown b\ any race of rufogularis. In konkakinhensis, all the rectrices are
tipped \\hite(Fig. 3a); theremigesarebluishgreyand lackablack bandacrossthem
(Fig. 3b); the fore-crown is grey streaked with black anda grey supercilium extends
above and behind the eye (Fig. 3c); and the vent is rich buffand extends onto the
belly (Fig. 3a). Garrulax konkakinhensis additionally shows an extreme degree of
chestnut on theear-coverts (Fig. 3c), an off-whitethroat, andextensive blacktipsto
the tertials and scapulars. These features are not shown to the same extent, are
shown irregularly,orarenotshowninsimilarcombination,byG. rufogularis. Garrulax
konkakinhensis most closely resembles G. rufogularis occidentalis and G. r.
rujiiineius in its general plumage pattern but differs from these two taxa in reduced
levelsofrufous intheplumage. Allthreetaxashare,toavaryingextent,chestnutear-
coverts, black on the crown, and the colourofthe mantle, wing-coverts and breast.
Additionally. G. konkakinhensis shares three plumage features with G. cineraceus
and G. lunulaius: white tips to the rectrices, the absence ofa black band across the
remiges. and the vent and belly are buff.
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Figure 1. Location of Kon Ka Kinh Nature
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Figure 2. Land-use in Kon Ka Kinh
Nature Reserve
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Jonathan C. Eames Charles Eames 12 Bull. B.O.C. 2001 121(1)
Plate 1. Holotype adult male Chestnut-eared Laughingthrush Garrulax konkakinhensis (lower)
and Rufous-chinned Laughingthrush Garrulax rufogularis intensior (upper). Original watercolour
painting by Charles Eames.
Jonathan C. Eames & Charles Eames 13 Hull. n.oc. 2001 I2KD
Figure3c
Figure 3a. Ventral view ofthe holotype ofChestnut-eared Laughingthrusfa Garrulax konkakinhensu
adult male, trapped and photographed on the summit ridge of Mount Kon Ka Kinh. Gia Lai
pro\ince. Vietnam, on I April 1999. Figure 3b. Protlle ofthe holotype. Figure 3c. Head detail ofthe
holotype. Photographs byJ. C. Fames. Figure 3d. Profiles ofthe holotype(middle)and two Datatypes
(juveniletopand femalebottom)ofChestnut-eared Laughingthrush Garrulaxkonkakinhensis
&
Jonathan C. Eames Charles Eames 14 Bull. B.O.C. 2001 121(1)
Tibet
BramaputraRiver G-r.assamensis
G.r.rufiberbis
Figure 4. The approximate geographical ranges of Garrulax rufogularis and G.
konkakinhensis
In the following description a quantitativejudgment ofcolour has been made,
wherever possible, using Smithe (1975) whose colour descriptions and numbers
appearinparentheses followingourown subjective determination.
The feathers ofthe foreheadare grey (MediumNeutral Gray 84) withblack(Jet
Black 89) tips and central shaft streaks. The black tips and central shaft streaks
becomebroaderonthecrownandnape.Thegrey(MediumNeutralGray84)supercilium
mergeswiththesidesofthecrown,extendingfromabovetobehindtheeye. Theear-
coverts are chestnut (Kingfisher Rufous 240). A black (Jet Black 89) malar stripe
extends in an unbroken line from the gape, bordering the chestnut ear-coverts and
mergeswiththeblackfeathersonthesidesofthethroat. Theloresarepalebuff(Pale
PinkishBuff12ID),withblackishfeatheringimmediatelyinfrontoftheeye.Thechin
andthroat are off-white, faintly tingedbuff(Pale Pinkish Buff 12ID), gradingto a
slightly richerbuffon the sides ofthe chin andthroat. The feathers ofthe chin and
throatirregularlyshowfaintblackishcentres,whicharenarrowlyfringedblack,which
extendontothesidesofthethroatandneck. Theupperbreastispalegrey(Glaucous
80) washedbuff(Light Drab 119C) and is narrowly fringedblack andwithnarrow
blackcentralshaftstreaks. Thebellyandflanksarepaleorange-buff(ClayColor26)
becomingrichbuff(Antique Brown37)onthevent. Themantle, andlesser,median
andgreaterwingcovertsareolive-buff(DarkDrab 119B)becomingawarmerbrown
(RawUmber 123)ontheback,rumpandscapulars,andarefringedblack,broadlyso
on the mantle, greater coverts and scapulars. The upperparts are thus boldly and
irregularlybarred. Thealulaisblackbutwithagreybasalhalftotheouterweb. The
primary coverts are blackish-brown (Sepia 119). The outer webs ofthe outermost
n
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Jonathan C. Eames CharlesEames 15 Bull B.O.C 2001 121(1)
sc\en primaries arc fringed bluish-white, formingan indistinct pale wing panel. This
bluishwbitepanelgradestoolive-brown(GroundCinnamon239)onthe innerprimaries
andsecondaries, includingthetertials. The innerwebsoftheprimariesandsecondaries
are light blackish-brown (Blackish Neutral Gray 82). The tipsoftheouterwebsofthe
innermost threeprimariesandall thesecondariesareblack with a narrow white fringe.
Thispattern gradually becomes moreextensiveacross the secondaries so that tertials
are \er\ broadl) tipped black with pronounced white fringes. The uppertail co\cits
are rufous-brown (Antique Brown 37). There are 12 rectrices which are mid-brow
(Raw Umber23)and which gradetoalessrufousandmoreolivebrowntowards then-
tips. All rectrices have very broad sub-terminal black bands and are broadly tipped
white. On the outermost two pairs, the black extends almost halfway along their
entire length, whereas on the innermost pair, the black extends for 20 mm. The
undersideofthetail isblackish-brown(BlackishNeutralGray 82)andall feathersare
broadly tipped white. Bare parts: bill - upper mandible dark horn with a pale horn
lowermandible; legstleshhornwithyellowsoles; irisbrown.
Measurements oftype (mm): maxilla (tip to skull) 24.5; tarsus 40; wing (max.
chord)99;tail 123.
Paratypes. Twoadditional specimenswerecollectedonMountKonKa Kinhandare
currentlyheld at BirdLife International inHanoi (Fig. 3d). A femalecollectedon29
April 1999ate. 1.650m.No.l945.2.1 handajuvenilemalecollectedon23April 1999
atc. 1.600m.No.1945.2.12.Theirmeasurements(mm)are,respectively: maxilla23.5,
21.5 (tiptoskull);tarsus41,39;wing(max. chord)98,95;tail 1 16, 1 12. SpecimenNo.
1945.2.1 1 hadadarkbrowniris;billwithadarkhornuppermandibleandapalehorn
lowermandible; legs fleshhorn. SpecimenNo. 1945.2.12hadabillwithadarkhorn
upper mandible and a pale horn lower mandible; legs flesh horn. Iris colour was
unrecorded. The condition ofthe gonads in these two specimens was not noted.
Paratype variation. The adult female appears very similarto the male holotype but
shows slightly broaderwhite tips to the tertials and buffish tips to the outerwebs of
the innermost primary andthe secondaries. Thetips totheunderside ofthe rectrices
areoff-white.Thefledgedjuvenileshowscharacteristicallysoftandunder-developed
plumageandablackcrownwithonlyasmall amountofgreyevidentbehindtheeye.
Noothersignificant plumagedifferences are apparentwith theholotype (Fig. 3d).
Ecologyandbehaviour. Theonly fieldobservation relatestoaflockofat leastthree
birdsfromamongstwhichJCEcollectedajuvenilemaleon23 April 1999atc. 1.600m.
This flock was observed moving rapidly through bamboo undergrowth. On Mount
KonKaKinh. G. konkakinhensisoccurssympatricallywith Red-tailed Laughingthrush
G. milneifromc. 1.600mtothesummit. Garrulaxkonkakinhensismayoccurat lower
elevations but determination ofthis was difficult to verify because the species was
notheard singing orindeed makinganyvocalizationsduring March and April. Pans
ofG. milneiwererecordedsingingand holdingterritoryduringthe sameperiod. The
loweraltitude limit ofG. konkakinhensis has notbeen determined; ifit extends to c.
1,500m itwouldoverlaptherangeofBlack-hooded Laughingthrush G. milleti. which
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Jonathan C. Eames Charles Eames 16 Bull B.O.C. 2001 121(1)
wasrecordedcommonlyuptoc. 1,500m. ThecloselyrelatedGarrulaxrufogularisis
noted to also be a skulker, more often heard than seen and doubtless overlooked.
Garrulaxrufogulariskeepsinpairsorsmallfamilyparties,hauntinglowbushesand
feedingmostlyontheground. Ittakestothewingwithreluctanceandflightisweak
&
andill-sustained(Ali Ripley 1972).
Habitat. OnMountKonKa Kinh, G. konkakinhensis was found intheundergrowth
ofprimary upper montane evergreen forest (as defined by Whitmore 1992). The
holotype was collected from the narrow summit ridge where bamboos, including
Arundinaria baviensis and Schizostachyum sp., were predominant in the
undergrowth.Boththeholotypeandthetypeserieswerecollectedfromuppermontane
evergreen forest, dominated by broadleaftree species from the families Fagaceae,
Lauraceae, Magnoliaceae, Hamamelidaceae, Theaceae, Ericaceae, Myrtaceae and
Araliaceae. Thisforestwasbeingloggedforlarge,emergentFokieniahodginsiiand
in many places the canopy was broken and there were many clearings. On Mount
KonKaKinh,fromc.1,600tothesummitat 1,748m,theforestcanopyheightwasc.
m
10-15m,with20 treesinflatterareasofthesummitplateau.IntheIndiansubcontinent
m
Garrulax rufogularis has been noted to occur from 600-1,900 in dense thickets,
scrubjungle, dense undergrowth in oak and rhododendron forest, forest edge and
&
especiallysecondarygrowthnearcultivation(Ali Ripley 1972).InnorthernVietnam
G. r. intensiorisknowntooccurfrom 1,500mto2,500m(Delacour&Jabouille 1931).
Distribution. Garrulax konkakinhensis was discovered on Mount Kon Ka Kinh
(GiaLaiprovince) intheCentralHighlandsofVietnamandiscurrentlyknownonly
from this site (Figs.l and 2). It is likely to occurto the north in adjacent Kon Turn
province and could conceivably occur in Laos, because forest habitat within the
species' altitudinal range extends across theprovincial and international borders.
Inthiscontext,itisworthmentioningsightingsofalaughingthrush,seeninthePhou
Ahyonareaofsouth-eastLaosbetween 1,350-1,450minMay 1996, whichshowed
somesimilaritiestoG.rufogularis(Duckworthetal. 1999).Whilstnotingsomeplumage
featureswhicharealsoshownbyG. konkakinhensis,theobservernotedredremiges
and a black wing bar which are absent in this new species. On the basis ofthese
sightings, the species in question was provisionally identified as Spotted
LaughingthrushG. ocellatus(R.Timminsinlift. 1996). Intheabsenceofanyvoucher
specimen, we believe this sight record is bestjudged as Garrulax sp.
Etymology.Wenamethis species afterthetype locality, MountKonKaKinh (Figs.
1 and2). This little-studiedareawasrecentlygazettedas anaturereserveandthis is
the firstbird species to be named forthe site.
Taxonomic considerations
Withinthegenus Garrulax,thereare several species groupsthatareheredefinedas
monophyletic subsets ofspecies (Amadon & Short 1992). An example ofa species
group within this genus are G. etythrocephalus, G. ngoclinhensis and G. yersini
(Eames et al. 1999). Garrulax konkakinhensis comprises a species group together
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Jonathan C. Eames Charles Eat 17 Hull. B.O.C 2001 121(1)
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Jonathan C. Eames Charles Eames 18 Bull. B.O.C. 2001 121(1)
with three other Sino-Himalayan species, G. rufogularis, G. cineraceus and G.
lumilatus. Herewepresentthecase foraffordingspecific rankto G. konkakinhensis
based on its morphology in comparison with G. rufogularis, with which it shows a
G
strongsimilarity. Basedonplumage, G. cineraceusand lumilatus showfarfewer
similarities and, byanalogy, wouldbe placedfurtheraway inthephylogeny.
Deignan (1964) recognized seven subspecies within Garrulax rufogularis,
distributedasfollows: G. r occidentalisextendsthroughtheHimalayasfromPakistan
eastward to north-western Uttar Pradesh in India; G. r. grosvenori is known from
Rekcha, DailekhDistrict inwestNepal; G. r. rufogularis occurs fromcentralNepal
eastward, through Bhutan into the Indian state of Assam, north of the River
Brahmaputra; G. r. assamensisisknownfromMargheritainnorth-easternAssam; G.
r. rufitinctusisknownfromthehilltractsofAssamsouthoftheBrahmaputraRiver;
G. r. rufiberbisisknownfromKachin StateinnorthernBurma, and G. r. intensioris
known only from its type locality at Sa Pa in north-western Vietnam (Fig. 4).
Subsequently, Ripley placed G. r. grosvenori in synonomy with G. r. occidentalis
andthereforethisformhasnotbeenconsideredfurtherinthisreview(Ripley 1982).
The distributions of these taxa are imperfectly known and the species has been
predictedtooccurintheChumbivalley(Yadong)andintheMedogareaofsouthand
south-east Xizang province, China (Tibet) (MacKinnon & Phillipps 2000). On 1
March 1999,thespecieswasobservedatRuili,insouth-westYunnanprovince(China)
(Dymond&Thompson2000).
Throughout its range, G. rufogularis is veryvariable, withvariation inplumage
charactersinsomecasesclinalandinothersabruptandmosaic.Allsevensubspecies
of G. rufogularis show rufous tips to the rectrices, a black wing panel across the
remigesandblackontheforecrowntoavariabledegree.Furthermore,allsubspecies
showavariableextentoforangeonthechinandthroat. Forexample,theholotypeof
G. r. rufiberbis shows only a small extent oforange on the chin, whereas in G. r
occidentalis, G. r. rufitinctus and G. r. assamensis the orange is more extensive.
Other characteristics, such as the colour ofthe upperparts, which vary from light
TABLE 2
Summary ofplumage features of Garrulax konkakinhensis. G. rufogularis,
G. cineraceus and G. lunulatus
Taxon Wing Orange-brown Gney forehead Buffvent
panel tips to rectices and supercilium and belly
Garrulax konkakinhensis - - + +
G. rufogularis rufogularis + + - -
G. r. occidentalis + + - -
G. r. assamensis + + - -
G. r. rufitinctus + + - -
G. r. rufiberbis + + - -
G. r. intensior + + - -
G. cineraceus - - - +
G. lunulatus - - - +
i
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Jonathan C. Eames Charles Eat Bull B.O.C 2001 121(1)
Alii
I I i
Comparison ofbiometrics amongsl Garrulax rufogularis and G. konkakinhensis based on
specimens in 1he Natural Historj Museum, rring. In each cell, the biometric range isgiven, followed
h> the mean, standarddeviation and finally the sample size.
All measurementsare in mm.
Li.xoii \taxilla(liptoskull) Tarsus Wing(max. chord Tail Sex
G.rufogularis 24.25.24.24.24.5. 33.5.36.5.36.34.5.38. 95,95,92,98,94,93, 106.II0.5.108.11I.I04. 2m. 8?
rufogularis 23 24.5,222522 36,37,35,36.5,36.5 96,91,95,89(93.8) 105.5,113,100.5,106,102.!
(23J9){1.081}[10] (36.0){1.301}[10] (2.616}[10] (106.7)13.945l[l()|
G.r.intensior 20.25.24.5(25.2) 38.5.35.37(36.8) 97,98,95(96.7) 110,113.110 2m.If
[0.764}[3] (1.756}[3] 11.528113] (II1.0)11.7321 [3]
Gr.rufiberbis 24.5(24.5)[1] 34(34.0)[1] 93(93.0)|1] 101(101.0)|1| Im
(J.r.occidentalis 719999997\S 33.5.36.33.34.35.5. 93.96.99.92,91.91. 107.5.113,106,111,117. 2f".lm.7V
24.23.24.24.22.5 34.34.36,34.34.5 90,98,94,93(93.7) 106,115,115,110,109
(23.0){0.85}[10] (34.5)|1.0391|10] 13.0571(10] (111.0)13.9331(10]
G.r.rufitinctus 23.5.broken.18.5 36,37,34(35.7) 95,92,86(91.0) 116.113,98(109.0) 1f,2?
(21.0){3.536}[2] [1.528][3] 14.5831 [3] •9.644][3]
G.konkakinhensis 24.5,23.5.21.5 40,41,39(40.0) 99,98,95(97.3) 123.116.112(117.0)
(23.2){1.528}[3] 11.0001[3] {2.0821[3] 15.5681(3] 2m.If
olive-brown to darkbrown, and the colourofthe vent, which varies from cinnamon
to a dark cinnamon, show clinal variation. Upperpart and vent colouration become
progressivelydarkerandbrownerasonemoveseastwardsandintheeasternmost G.
r. intensior black and dark browns show their greatest expression. Other features,
such as the chestnut ear-coverts, show a mosaic expression since only two ofthe
G
subspeciesof rufogularis,whichdonotallhaveallopatricranges(G. r occidentalis
G
and r. rufitinctus),showthisfeature.Thus,thewesternmostform,G. r. occidentalis,
G
bears the closest resemblance to konkakinhensis in the extent oforange on the
G
ear-coverts and in general plumage colouration, whereas r. intensior, which has
G
the closest geographic proximity, bears the leastresemblance to konkakinhensis.
Table 1 details the general morphology ofall seven forms ofG. rufogularis, and G.
konkakinhensis,basedonanexaminationoffourholotypespecimensandadditional
skins ofG rufogularis taxa in the American Museum ofNatural History and atThe
Natural History Museum. Although bearingstrongresemblancetothewestern races
G G
of rufogularis, konkakinhensisismorphologicallysufficientlydistincttowarrant
specific treatmentbecause itshowsfouruniqueplumage featuresthatarenot shown
G
by any subspecies of rufogularis. Table 2 summarises these features, and a1st)
G
includes the related cineraceus and G. lunulatus. The possession ofwhite tips to
the rectrices, the absence ofa black band across the remiges, and a buffvent and
belly are plumage features that G. konkakinhensis shares with G. cineraceus and G.
lunulatus, indicating a shared ancestry with these taxa. The distinctive morpholog)
ofG. konkakinhensis and G. rufogularis indicates that the level ofgenetic variation
between them is greater than that among the seven described subspecies of G.