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The genus Vietbocap Lourenço & Pham, 2010 in the Thien Duong cave, Vietnam: A possible case of subterranean speciation in scorpions (Scorpiones:
Pseudochactidae)
Wilson Lourenço, Dinh-Sac Pham, Thi-Hang Tran
To cite this version:
Wilson Lourenço, Dinh-Sac Pham, Thi-Hang Tran. The genus Vietbocap Lourenço & Pham, 2010 in the Thien Duong cave, Vietnam: A possible case of subterranean speciation in scorpions (Scor- piones: Pseudochactidae). Comptes Rendus Biologies, Elsevier, 2018, �10.1016/j.crvi.2018.03.002�.
�hal-01772162�
The genus Vietbocap Lourenc ¸o & Pham, 2010 in the Thien Duong cave, Vietnam: A possible case of subterranean speciation in scorpions (Scorpiones: Pseudochactidae)
Le genre Vietbocap Lourenc ¸o & Pham, 2010 dans la grotte Thien Duong, Vietnam : un cas possible de spe´ciation souterraine chez les scorpions (Scorpiones : Pseudochactidae)
Wilson R. Lourenc ¸o
a,*, Dinh-Sac Pham
b, Thi-Hang Tran
b, Thi-Hang Tran
b,caEvolution,biodiversite´ (ISYEB),Muse´umnationald’histoirenaturelle,Sorbonneuniversite´s,Institutdesyste´matique,UMR7205CNRS, MNHN,UPMC,EPHE,CP53,57,rueCuvier,75005Paris,France
bGraduateUniversityofScienceandTechnology(GUST),VietnamAcademyofScienceandTechnology(VAST),CauGiay,Hanoi,Vietnam
cHanoiCenterforpreventivemedicine,70,NguyenChiThanh,DongDa,Hanoi,Vietnam
* Correspondingauthor.
E-mailaddress:wilson.lourenco@mnhn.fr(W.R.Lourenc¸o).
Keywords:
Scorpion Newspecies Troglobiticelement Vietnam
PhongNha–KeBangNationalPark ThienDuongcave
Intra-cavespeciation
Motscle´s: Scorpion Nouvelleespe`ce Troglobie Vietnam
PhongNha–KeBangNationalPark GrotteThienDuong
ABSTRACT
TwonewspeciesofscorpionbelongingtothefamilyPseudochactidaeandtothegenus VietbocaparedescribedbasedonspecimenscollectedintheThienDuongcave,which belongstotheVomcavesystem,inthePhongNha–KeBangNationalPark,QuangBinh Province, Vietnam. The previously described species from this cave, Vietbocap thienduongensisLourenc¸o&Pham,2012wascollectedintheinitialsectionofthecave (1500to1800mfromthecaveentrance)andprovedtobeatruetroglobiticelement.The diagnosisofthisspecies,onlyknownfrommales,iscompletedbasedonfemalescollected at750mfromthecaveentrance.Thetwonewspeciesdescribedherewerecollected respectivelyat3000and5000mfromthecaveentranceandarealso truetroglobitic elements,very similar to V. thienduongensis,but showingsome clear morphological differences.Thisobservedsituationsuggestsapossiblecaseofspeciationwithinthecave system,thefirstoneeverreportedforscorpions.Thepopulationfoundat5000mfromthe entranceofthecaveisatotalnewrecordofdistancefromacaveentranceforscorpions.
RE´ SUM E´
Deuxnouvellesespe`cesdescorpionappartenanta` lafamilledesPseudochactidaeetau genreVietbocapsontde´critesa` partird’exemplairescollecte´sdanslagrotteThienDuong, laquelleappartientausyste`medesgrottesVomdansleparcnationalPhongNha–KeBang danslaprovincedeQuangBinh,Vietnam.Laseuleespe`cede´ja` de´critedecettegrotte, VietbocapthienduongensisLourenc¸o&Pham,2012,ae´te´ collecte´edanslapartieinitialede celle-ci(entre1500et1800me`tresdel’entre´e)etae´te´ confirme´ecommeunve´ritable e´le´menttroglobie.Ladiagnosedecetteespe`ce,connueuniquementa` partirdesmaˆles,est
1. Introduction
As already outlined in several previous publications [1–5], the family Pseudochactidae Gromov, 1998 most certainly contains the most remarkable scorpions de- scribed inthe last twentyyears. Thefirst species tobe discoveredwasPseudochactasovchinnikoviGromov,1998, foundinanisolatedmountainousregionofsoutheastern Uzbekistanand southwestern Tajikistan,in CentralAsia [6]. A second genus and species, Troglokhammouanus steineri Lourenc¸o,2007, wasdescribed fromkarstcaves inLaos[1].Althoughthisspecieswasfoundinsideacave, itsmorphologicalcharacteristicsdonot correspondtoa totallytroglobiticelement.ThisLaotianspeciesreopened the question about the origins and affinities of the Pseudochactidae and led to new biogeographical inter- pretations[1].
Inthefollowingyears,scorpionshavebeenprospected inkarstcavesystemsinVietnam,andseveralspecimensof anewpseudochactidscorpionwerecollectedintheTien Soncave,whichbelongstothePhongNhasystem.These weredescribedasanewgenusandspecies,Vietbocapcanhi Lourenc¸o&Pham,2010,whichrepresentsatruetroglobitic element[4].Subsequentsurveysin thecavesystemsof Vietnam have been carried out and another species of pseudochactidscorpionwascollectedintheThienDuong cave, which belongs tothe Vomcave system.The new species, Vietbocap thienduongensis Lourenc¸o & Pham, 2012 showed features of a totally troglobitic element [5]. Almost simultaneously, one more new species of Vietbocapwascollected in a cavein Laos;Vietbocaplao Lourenc¸o,2012,onceagainprovedtobeatruetroglobitic element[2]
Only several years after the description of the first species belonging to the genus Troglokhammouanus Lourenc¸o,2007,asecondspecieswasfoundanddescribed from another cave in Laos [3]. The description of Troglokhammouanus louisanneorum Lourenc¸o, 2017 was basedonasinglefemalespecimenandtheelementsofthis genusareapparentlylesscommonthanthoseofthegenus Vietbocap.
Thefactthatseveralpseudochactidelementsoriginat- ingfromcaveswithinthesamemajorkarstsystemhave beenfoundinLaosandVietnamsuggestthatthisregionof Southeast Asia may represent a refuge or centre of endemismforthisfamily.
Inrecentyears,moreintenseresearchwasconcentrate intheThienDuongcave,whichisamajorcaveinthiskarst system(see nextsection). Prospectionswerecarried on muchdeeperdistancesfromtheentranceofthecaveand further elementsbelongingtothegenusVietbocapwere located.Thestudyofthespecimenscollectedrespectively at3000and5000mfromthecaveentranceshowedthat thesewerenewspecies;similartoV.thienduongensis,but presenting some clear morphological differences. This observed situation could suggest a possible case of speciation within the cave system, the first one ever reportedforscorpions.Moreover,thepopulationfoundat 5000m fromtheentrance of the caverepresenta new recordofdistancefromacaveentranceforscorpions.
Wewillnotre-discussherethecontroversialphyloge- neticandbiogeographicalaspectsconcerningthispeculiar scorpionfamily,sincemostbasicpointshavealreadybeen largelydiscussedbyLourenc¸o[1].Usingmoleculartools, Sharma et al. [7] strongly supported the monophyly of pseudochactids, chaerilids, and buthids. The precise relationshipsamongthesethreefamiliesremainhowever strongly ambiguous. More detailed information on the orogenyandgeodynamicsofSouthEastAsia,andonthe location, ecology and climate of the national park and caves,canbefoundinLourenc¸oandPham[4].
2. TheThienDuongcaveintheVomcavesystem
TheThienDuongcave(alsocalledParadisecave)where thenewspecieswerefoundislocatedinthePhongNha–Ke Bang National Park, 60km northwest of Doˆng Ho´i city (Figs. 1–2). The Thien Duongcave is at anelevation of 200mabovesealevel,nearthewestbranchofHoChiMinh Highway,inSonTrachCommune,BoTrachDistrict,Quang BinhProvince,Vietnam.Thecavewasdiscoveredbyalocal peoplein2005,andinitiallythefirst5kmofthiscavewere explored by scientists from the British Cave Research Associationin2005.Morerecently,thewholeextensionof thecavewasexploredbythesameAssociation.Thecaveis 31km long,andinparts canreach100minheightand 150minwidth.TherearetwocavesystemsinPhongNha Ke Bang region:Phong Nhacavesystemand Vom cave system.However,thesesystemsaregloballyisolated,with nogeologicalconnectionsbeingknownbetweenthem[8].
ThePhongNha–KeBangkarstistheoldestmajorkarst area in Asia. It has been subject to massive tectonic comple´te´ea`partirdefemellescollecte´esa`750mdel’entre´edelagrotte.Lesdeux nouvellesespe`cesde´critesa`pre´sentonte´te´collecte´esrespectivementa`3000et 5000mdel’entre´edelagrotteetsonte´galementdese´le´mentstroglobies,plutoˆt similaires a` V. thienduongensis, maisavec des diffe´ rences morphologiques bien nettes.Lasituationobserve´ esugge` reunpossiblecasdespe´ ciationa` l’inte´ rieurdela grotte,lepremiersignale´ chezlesscorpions.Lapopulationtrouve´ ea` 5000mde l’entre´edelagrotterepre´senteunrecordabsoludedistancedel’entre´ed’unegrotte pourdesscorpions.
changes and comprises a series of rock types that are interbeddedincomplexways.Probablyasmanyasseven majorlevelsofkarstdevelopmenthaveoccurredasaresult oftectonicupliftandchangingsealevels,thusthekarst landscape of PNKB is extremely complex with high geodiversityandmanygeomorphicfeaturesofconsider- ablesignificance[4,8,9].
3. Methods
ScorpionswerecollectedbyscientistsoftheIEBRand thePhongNha–KeBangNationalPark,whileexploringthe cavewiththehelpofstandardelectrictorches.Theywere found on the cave walls and sometimes under rocks, approximatelyat 750, 3000and 5000mfromthemain caveentrance.Thislastdistanceisanewdistancerecord fromacaveentrancefor ascorpion.Measurementsand illustrationswere madeusing a Wild M5stereo-micro- scope with a drawing tube and an ocular micrometer.
MeasurementsfollowthoseofStahnke[10]andaregiven inmm. Trichobothrialnotations arethosedeveloped by Soleglad &Fet [11]and the morphologicalterminology mostlyfollowsthatofHjelle[12]andLourenc¸o[1,13].
4. Taxonomictreatment
FamilyPseudochactidaeGromov,1998 SubfamilyVietbocapinaeLourenc¸o,2012 GenusVietbocapLourenc¸o&Pham,2010
Vietbocap thienduongensis Lourenc¸o & Pham, 2012 (Figs.3–5)
Enlargeddiagnosisforthefemale
Vietnam,QuangBinhProvince,PhongNha–KeNational Park, Thien Duong cave (17831’10.3’’ N–106813’22.9’’E), initialsectionofthecave(750mfromthecaveentrance), 18/V/2016(T.-DDo,T.-H.Tran&T.-N.Nguyen),2females.
Material deposited in the ‘Muse´um national d’histoire naturelle’,Paris.
Generalcolorationyellow, lesspalethanonmalefor metasomalsegments andtelson; cheliceralteeth,telson tip,androwsofgranulesonpedipalpfingersdarkreddish.
Anteriormarginofcarapaceonlyslightlydepressed,witha concavity slightly stronger than that of male;carapace smooth, except for someisolate granules. Lateral ocelli absent. Pair of circumocular sutures complete in the posteriorregiontomedianoculartuberclewithabroadU- shaped configuration. Median ocelli absent; median tuberclerepresentedbyasmoothbutnotdepressedzone.
Anterosubmedialcarinaeabsentfromzonedelimited by circumocularsutures;furrowsobsolete.Cheliceraeshorter in the female; dorsal edge of fixed finger with four denticles (basal, medial, subdistal, distal); ventral edge with 3–4 very reduced denticles; movable finger with three denticles (medial, subdistal, external distal) on dorsal edge, withoutbasal denticles; ventraledge with 4–5reduceddenticlesandaweakserrula;externaldistal denticle smaller than internal distal denticle; ventral aspectoffingersandmanuswithnumerousmacrosetae.
Type-Dtrichobothrial pattern [11,14]with35 trichobo- thria per pedipalp: 12 on femur, of which 5 dorsal, 4 internal and 3 external (d1, d4, d5 and i4 extremely Fig.1.TheKarsticMassifwheretheThienDuongcaveislocated,showing
typicalvegetation(photobyCaoXuanLoc).
Fig.2. InteriorviewoftheThienDuongcave,3000mfromtheentrance, showingtwooftheco-authors(T.-H.T.&T.-H.T.)searchingforscorpions.
reduced);10onpatella,ofwhich3dorsal,1internaland 6 external (est extremely reduced); ventral surface withouttrichobothria;13trichobothriaonchela,ofwhich 5 on manus, 8 on fixed finger(ib2 extremely reduced);
dorsaltrichobothriaoffemurwith‘‘beta-like’’configura- tion. Sternum pentagonal, type 1 [15], strongly com- pressed horizontally,slightlylonger thanwide, external aspect not flat, with a concave region, posteromedian depressionround.Pectineseachwith3–4distinctmargin- al lamellae and 6–7 well-delineated median lamellae;
fulcraabsent;pectinaltoothcount7–7and7–8.Genital operculum completely divided longitudinally. Telotarsi each withseveralspinularsetae, notclearlyarrangedin rows.MetasomalsegmentVwithaweaklymarkedpairof ventrosubmedian carinae; no ventromedian carina be- tween ventrosubmedian carinae; metasomal carinae bettermarkedthanonmale.Pedipalpsshorterthanthose of male;fixed and movablefingersstrongly curved,but less than on male; dentate margins each with median denticlerowcomprisingsevenobliquegranularsub-rows;
internaland externalaccessorygranulesatbaseofeach sub-row.Respiratoryspiraclessmall,semi-ovaltoround.
Pro-andretrolateralpedalspurspresentonlegsI–IV.Tibial spursabsentfromalllegs.Telson longandlessbulbous thanonmale;vesiclesmoothonallfaces;aculeusshorter Fig.3.Vietbocapthienduongensis.Habitus,dorsalandventralaspects.
A–B.Maleholotype.C–D.Female.
Fig.4.Vietbocapthienduongensis.Maleinnaturalhabitat;800mfromthe caveentrance.
Fig. 5. Vietbocap thienduongensis. Female. A. Simple venom glands.
B.Sternum,genitaloperculumandpectines.C.MetasomalsegmentV andtelson,lateralaspect.D.Chelicera,dorsalaspect.E.Cuttingedgeof movable finger showing rowsof granules. F. Femur,dorsal aspect, showingtrichobothrialpattern.
than vesicle and weakly curved without a subaculear tubercle ventrally. Form of venom glands extremely simpleswithatotalabsenceoffolds(Fig.5).
Measurements(inmm)offemaleVietbocapthienduon- gensis
Totallength23.9.Carapace:length3.0;anteriorwidth 2.0;posteriorwidth3.2.Mesosomalength5.5.Metasomal segments:I,length1.2,width1.5;II,length1.4,width1.2;
III,length1.7,width1.1;IV,length2.2,width1.1;V,length 4.3,width1.0,depth1.0.Telsonlength4.6;vesiclewidth 1.4, depth 1.2. Pedipalp: femur length 4.0, width 1.0;
patellalength3.8,width1.2;chelalength7.5,width1.2, depth1.2;movablefingerlength4.4.
Reports: Sternum length/width, 1.2/1.2=1.00. Chela length/movablefingerlength,7.5/4.4=1.70.
Vietbocapaurantiacussp.n.(Figs.6–7)
Diagnosis:Anteriormarginofcarapacenotdepressed withaweaktomoderateconcavity.Lateralocelliabsent.
Pair of circumocular sutures complete in the posterior regiontomedianoculartuberclewithabroadU-shaped configuration. Median ocelli absent; median tubercle represented by a smooth but not depressed zone.
Anterosubmedial carinaeabsentfromzonedelimitedby circumocular sutures. Type-D trichobothrial pattern [11,14]with35trichobothriaperpedipalp:12onfemur, ofwhich5dorsal,4internaland3external(d1,d4,d5andi4
extremely reduced); 10 on patella, of which 3 dorsal, 1internaland6external(estextremelyreduced);ventral surfacewithouttrichobothria;13trichobothriaonchela,of which 5 on manus, 8 on fixed finger (ib2 extremely reduced); dorsaltrichobothriaoffemurwith‘‘beta-like’’
configuration.Sternumpentagonal,type1 [15],strongly compressedhorizontally,longerthanwide,externalaspect notflat,withaconcaveregion,posteromediandepression roundSterniteVwithawhiteposteriorinflatedtriangular zone.Telotarsieachwithseveralspinularsetae,notclearly arrangedinrows.MetasomalsegmentVwithamoderately markedpairof ventrosubmediancarinae; no ventrome- diancarinabetweenventrosubmediancarinae.Fixedand movable fingers strongly curved; dentate margins each with median denticle row comprising seven oblique granularsub-rows; internal and externalaccessory gra-
nulesatbaseofeachsub-row.Carinaeonmetasomaand pedipalps better marked than on the other species.
Respiratoryspiraclessmall,semi-ovaltoround.Pro-and retrolateralpedalspurspresentonlegsI-IV.Tibialspurs absentfromalllegs.
Typematerial:Femaleholotype,twofemaleparatypes.
Vietnam, Quang Binh Province, Phong Nha–Ke Bang National Park, Thien Duong cave (17831010.300N–
106813022.900E), mid-sectionof cave (3000m from cave entrance), 23/V/2013 (D.-S. Pham). Holotype and one paratype deposited in the ‘‘Muse´um national d’histoire naturelle’’,Paris.OneparatypedepositedintheInstituteof Ecology and Biological Resources, Vietnam Academy of ScienceandTechnology,Hanoi.
Etymology. The specific name is a Latin adjective referring to the orange coloration of the new species (aurantiacusinLatin).
Descriptionbasedonholotypeandparatypes(measu- rementsgivenafterthedescription).
Colour. Generalcoloration yellow to reddish-yellow, darkerthanintheotherspeciesofthegenus;cheliceral teeth,telsontip,pedipalpal andmetasomal carinaeand rowsofgranulesonpedipalpfingersdarkreddish.
Morphology. Chelicerae: dorsal edge of fixed finger with four denticles (basal, medial, subdistal, distal);
ventraledge with3–4very reduced denticles;movable Fig.6.Vietbocapaurantiacussp.n.Femaleholotype.Habitus,dorsaland
ventralaspects.
Fig.7.Vietbocapaurantiacussp.n.Femaleholotype.A.Cuttingedgeof movablefingershowingrowsofgranules.B.MetasomalsegmentsIV–V andtelson,lateralaspect.C.Chelicera,dorsalaspect.D–F.Trichobothrial pattern.D.Chela,dorso-externalaspect.E–F.Patellaandfemur,dorsal aspect.
finger with three denticles (medial, subdistal, external distal) on dorsal edge, without basal denticles; ventral edgewith4–5reduceddenticlesandamoderateserrula;
external distal denticle smaller than internal distal denticle; ventral aspect of fingers and manus with numerous macrosetae. Carapace: anterior margin not depressedwithaweaklytomoderatelymarkedconcavity;
lateralocelliabsent;medianoculartuberclerepresented byasmoothandnotdepressedzone;medianocelliabsent;
interocularfurrow obsolete.Onepairof weaklymarked circumocular sutures witha broad U-shapedconfigura- tion, also complete behind median ocular tubercle.
Anteromedianandposteromedianfurrowsshallow;pos- terolateralfurrowshallow,weaklycurved;posteromargi- nal furrow narrow, shallow. Carapace almost totally smooth, except for some isolated granules anteriorly.
Pedipalp segments apilose. Femur with five strongly markedcarinae;intercarinalsurfacessmooth.Patellawith sixstronglymarkedcarinae;ventrointernalcarinaewith somespinoidgranules;intercarinalsurfacessmooth.Chela with dorso-external and ventral carinae moderately marked; tegument smooth. Fixed and movable fingers strongly curved; dentate margins, each with median denticlerowcomprisingsevenobliquegranularsub-rows;
each sub-row comprising several small granules and internal and external accessory granules. Trichobothria orthobothriotaxic,TypeD[11,14],‘‘beta-like’’configura- tion,d2situatedondorsalsurface,d3andd4insameaxisof thefemur,parallelandclosertodorsoexternalcarinathan isd1,angleformedbyd1,d3andd4openingtowardinternal surface;totals:femur,12(5dorsal,4internal,3external);
patella,10(3dorsal,1internal,6external);chela,13(5on manus,8onfixedfinger).LegsItoIV:tibiaewithoutspurs;
basitarsieachwithapairofpro-andretrolateralspurs;
telotarsi each with several spinular setae, not clearly arranged in rows. Sternum pentagonal, type 1 [15], strongly compressed horizontally, longer than wide, externalaspect notflat,witha concaveregion,postero- mediandepressionround.Pectineseachwith3–4distinct marginal lamellae and 7–8 well-delineated median lamellaein females.Fulcraabsent.Pectinaltoothcount:
7–7inthefemaleholotype,6–7,6–6infemaleparatypes.
Genital operculum completely divided longitudinally.
Mesosoma:pre-tergites smoothand shiny;post-tergites II–VIsmooth,withoutgranules;VIIwithafewgranules anda pairof dorso-submediananddorsolateralcarinae, reaching posterior edge of segment. Sternites entirely smooth, acarinate; V with a white posterior inflated triangularzone;surfaceswithscatteredmacrosetae;distal margins with sparse row of macrosetae; respiratory spiracles small, semi-oval to round. Metasoma with a few shortmacrosetae.Ten carinaeon segments I toIII, weaklymarkedonII–III;eightcarinaeonsegmentIV;four on segment V. Dorso-submedian carinae moderately developedonsegmentsI–IV,absentonsegmentV;spinoid granules absent. Other carinae moderately to weakly developed on segments I–V. Telson long and slightly bulbous;vesiclesmoothonallfaces;aculeusshorterthan vesicleandweaklycurved,withoutasubaculeartubercle ventrally. Form of venom glands unknown, but most certainlysimilartothatofV.thienduongensis.
Measurements(inmm)offemaleholotypeofVietbocap aurantiacussp.n.
Totallength35.8.Carapace:length4.5;anteriorwidth 2.7;posteriorwidth4.8.Mesosomalength8.4.Metasomal segments:I,length1.9,width2.2;II,length2.2,width1.9;
III,length2.5,width1.8;IV,length3.2,width1.7;V,length 6.3,width1.6,depth1.4.Telsonlength6.8;vesiclewidth 2.2, depth 1.9. Pedipalp: femur length 6.0, width 1.3;
patellalength5.5,width1.6;chelalength10.6,width1.7, depth1.6;movablefingerlength6.3.
Ratios: sternum length/width, 2.1/1.8=1.67; chela length/movablefingerlength,10.6/6.3=1.68.
Relationships
Itisnoticeabletorecallthatthematerialusedinthe descriptionofVietbocapaurantiacussp.n.wasavailablefor studysinceanumberofyearsnow;however,onlyfemales of this species were available for the study. Contrarily, Vietbocap thienduongensiswas described on thebase of males only. Consequently, an objective comparative analysisofboth speciesbecomespossibleonlyafterthe morerecentdiscoveryoffemalesofV.thienduongensis(see previoussection).Thegeneralmorphologiesofallknown speciesofVietbocapareparticularlysimilar.Therefore,the identificationoftheseverycloselyrelatedspeciescanonly bebasedonsomeratherdiscretefeatures.
VietbocapthienduongensisandVietbocapaurantiacussp.
n. arethetwomostgeographicallyclosespeciesfoundin thecave,distantof1.0to1.5km.V.auranticussp.n.can, however,bedistinguishedbyanumberoffeatures:
biggersize(35.8vs23.9mm)anddistinctmorphometric values (see measurements and ratios following the description);
darkercoloration,moretoorange-yellow;
anteriormarginofcarapacenotdepressed;
sternum longer than wide (see ratios following the description);
metasomalsegmentsandpedipalpsbettercarinatedand granulated;
sterniteV withaconspicuouswhiteposteriorinflated triangularzone;
moderateserrulaoncheliceramovablefinger.
Vietbocapquinquemiliasp.n.(Figs.8–11)
Diagnosis: anterior margin of carapace slightly de- pressed,withaweakconcavity.Lateralocelliabsent.Pair ofcircumocularsuturescompleteintheposteriorregionto medianoculartuberclewithabroadU-shapedconfigura- tion.Medianocelliabsent;mediantuberclerepresentedby asmoothandonlyslightlydepressedzone.Anterosubme- dialcarinaeabsentfromzonedelimitedbycircumocular sutures.Type-Dtrichobothrialpattern[11,14]with35tri- chobothriaperpedipalp:12onfemur,ofwhich5dorsal, 4 internal and 3 external (d1, d4, d5 and i4 extremely reduced);10onpatella,ofwhich3dorsal,1internaland 6external(estextremelyreduced);ventralsurfacewithout trichobothria; 13 trichobothria on chela, of which 5 on manus,8 on fixedfinger(ib2 extremelyreduced);dorsal
trichobothria of femur with ‘‘beta-like’’ configuration.
Sternum pentagonal, type 1 [15], strongly compressed horizontally,slightlylongerthanwide,externalaspectnot flat, with a concave region, posteromedian depression round.Telotarsieachwithseveralspinularsetae,notclearly arranged in rows.Metasomal segment V with a weakly markedpairofventrosubmediancarinae;noventromedian carina between ventrosubmedian carinae. Fixed and movable fingers strongly curved; dentate margins each with median denticle row comprising seven oblique granularsub-rows;internalandexternalaccessorygranules atbaseofeachsub-row.Respiratoryspiraclessmall,semi- ovaltoround.Pro-andretrolateralpedalspurspresenton legsI–IV.Tibialspursabsentfromalllegs.
Typematerial:Male holotype,two femaleparatypes.
Vietnam, Quang Binh Province, Phong Nha - Ke Bang National Park, Thien Duong cave (17831010.300N–
106813022.900E), mid-section of cave (5000mfrom cave entrance), 6/IV/2015 (D.-S. Pham). Holotype and one
paratype deposited in the ‘‘Muse´um national d’histoire naturelle’’,Paris.OneparatypedepositedintheInstituteof Ecology and Biological Resources, Vietnam Academy of ScienceandTechnology,Hanoi.
Etymology. The specific name is a Latin noun in appositionreferringtothedistancefromthecaveentrance, 5000m(quinquemiliainLatin)wherethenewspecieswas found.
Description based on male holotype and female paratypes(measurementsgivenafterthedescription).
Fig.8.Vietbocapquinquemiliasp.n.Maleholotype.Habitus,dorsaland ventralaspects.
Fig.9.Vietbocapquinquemiliasp.n.Maleinnaturalhabitat;5000mfrom caveentrance.
Fig.10.Vietbocap quinquemiliasp.n. A–C.Maleholotype.D.Female paratype.A.Chelicera,dorsalaspect.B.Cuttingedgeofmovablefinger showingrowsofgranules.C–D.MetasomalsegmentVandtelson,lateral aspect.
Fig.11.Vietbocapquinquemiliasp.n.Maleholotype.A–C.Trichobothrial pattern.A.Chela,dorso-externalaspect.B–C.Patellaandfemur,dorsal aspect.
Colour. General coloration very pale yellow almost whitish, paler than all the other known species in the genus;cheliceralteeth,telsontipandrowsofgranuleson pedipalpfingersslightlyreddish.
Morphology. Chelicerae: dorsal edge of fixed finger with four denticles (basal, medial, subdistal, distal);
ventraledge with3–4very reduced denticles;movable finger with three denticles (medial, subdistal, external distal)onthedorsaledge,withoutbasaldenticles;ventral edgewith4–5reduceddenticlesandamoderateserrula;
external distal denticle smaller than internal distal denticle; ventral aspect of fingers and manus with numerous macrosetae. Carapace: anterior margin only slightlydepressedwithaweaklymarkedconcavity;lateral ocelli absent; median ocular tubercle represented by a smoothand onlyslightlydepressedzone;median ocelli absent;interocular furrow obsolete.One pairofweakly marked circumocular sutures with a broad U-shaped configuration,alsocompletebehindmedianoculartuber- cle. Anteromedianand posteromedian furrowsshallow;
posterolateral furrow shallow, weakly curved; postero- marginalfurrownarrow,shallow.Carapacealmostentirely smooth,exceptforsomeveryisolatedgranulesanteriorly.
Pedipalpsegments apilose. Femur withfive carinae,all moderatetoweak;intercarinal surfacessmooth. Patella withsixdiscerniblecarinae;ventrointernalcarinaewith somespinoidgranules;intercarinalsurfacessmooth.Chela withdorso-externalandventralcarinaeweaklymarked;
tegument smooth. Fixed and movable fingers strongly curved;dentatemargins,eachwithmediandenticlerow comprisingseven obliquegranular sub-rows;each sub- rowcomprisingseveral smallgranulesand internaland externalaccessory granules.Trichobothriaorthobothrio- taxic,typeD[11,14],‘‘beta-like’’configuration,d2situated on dorsalsurface, d3 and d4 insame axisof thefemur, parallelandclosertothedorsoexternalcarinathanisd1, angleformedbyd1,d3andd4openingtowardtheinternal surface;totals:femur,12(5dorsal,4internal,3external);
patella,10(3dorsal,1internal,6external);chela,13(5on manus,8onfixedfinger).LegsItoIV:tibiaewithoutspurs;
basitarsieachwithapairofpro-andretrolateralspurs;
telotarsi each with several spinular setae, not clearly arranged in rows. Sternum pentagonal, type 1 [15], strongly compressed horizontally, slightly longer than wide, external aspect not flat, with a concave region, posteromedian depression round. Pectines each with 3 distinct marginal lamellae and 7–8 well-delineated median lamellae in both sexes. Fulcra absent. Pectinal tooth count: 8–8 in males, 7–7 in females. Genital operculum completely divided longitudinally; genital plugs observed in the male. Mesosoma: pre-tergites smooth and shiny;post-tergites II–VI smooth;granules totallyabsent;VIIequallywithoutgranulesandapairof dorso-submediananddorsolateralcarinae,reachingpos- terioredgeofsegment.Sternitesalmostentirelysmooth, acarinate; surfaces with scattered macrosetae; distal margins with sparse row of macrosetae; respiratory spiracles small, semi-oval to round. Metasoma with a fewshort macrosetae.Tencarinaeon segments ItoIII;
eightcarinaeon segmentIV;fouron segmentV.Dorso- submedian carinae moderately developed on segments
I–IV,absentonsegmentV;spinoidgranulesabsent.Other carinaemoderatelytoweaklydevelopedonsegmentsI–V.
Telsonlongandslightlybulbousinthemale,slenderinthe female;vesiclesmoothonallfaces;aculeusshorterthan vesicleandweaklycurved,withoutasubaculeartubercle ventrally. Form of venom glands unknown, but most certainlysimilartothatofV.thienduongensis.
Measurements (inmm)of maleholotypeand female paratypeofVietbocapquinquemiliasp.n.
Total length 25.4/20.2. Carapace: length 3.2/2.5;
anteriorwidth2.0/1.8;posteriorwidth3.3/2.7.Mesosoma length 7.4/6.1. Metasomal segments: I, length 1.2/1.0, width1.6/1.2;II,length1.4/1.2,width1.4/1.0;III,length 1.6/1.3,width1.3/0.9;IV,length2.1/1.6,width1.2/0.8;V, length4.2/3.2,width1.2/0.8,depth1.1/0.8.Telsonlength 4.3/3.3; vesicle width 1.4/1.1, depth 1.2/0.9. Pedipalp:
femurlength4.1/2.9,width1.0/0.8;patellalength4.0/3.1, width1.1/0.9;chelalength7.5/5.7,width1.2/1.0, depth 1.1/0.9;movablefingerlength4.4/3.4.
Reports: Male: Sternum length/width, 1.4/
1.2=1.17. Chela length/movable finger length, 7.5/
4.4=1.70. Female: Sternum length/width, 1.1/
1.0=1.10. Chela length/movable finger length, 5.7/
3.4=1.68.
Relationships
Vietbocapquinquemiliasp.n.isgeographicallyseparat- edofVietbocapaurantiacussp.n. by2km.Theirgeneral morphology although similar presents a number of differencesandinfactV.quinquemiliaseemsmoreclosely relatedtoV.thienduongensis.Thisnewspeciescanhowever becharacterizedbyanumberofparticularfeatures:
small size (only 20.2mm for female) and distinct morphometric values (see measurements and ratios followingthedescription);
averypalecolorationalmostwhitish;this isthepaler speciesknownforthegenus;
median ocular tubercle on carapace only slightly depressed;
cheliceralserrulamoderatelymarked;
tergitesgloballysmooth;
pedipalpcarinaeveryweaklymarked.
5. Discussion
Casesofmorethanonespeciesofagivengenus,living inacommon cavesystem,havebeenrecordedforother zoological groups. For example, Bayer and Ja¨ger [16]
reported the presence of two spiders of the genus Heteropoda, namelyHeteropoda maxima and Heteropoda steineri in the Xe Bangfai Cave system.Although these authorsindicatethatH.steineriwouldbemorerestricted todeeperpartsinthecave, theysuggestthatthesetwo verymobilespeciescouldpotentiallymeet.Anoticeable parallelcasewasalsoobservedforthespeciesofthecave scorpiongenusAlacranFranckeinMexico[17].Intemper- ate regions, several species of a same beetle genus are
knowntoco-occurfrequentlyinasamecave,likeforthe Aphaenops in the Pierre Saint-Martin system in French Pyrenees [18]. Most reported cases however show that theseparapatricand/oralmostsympatricspeciespresent marked distinct degrees of adaptation to cave and/or subterraneanlife.
Thegeneral assumptionthat cavespeciesevolved, in mostcases,directlyfromsurfaceancestors,wasrecently questionedbyJuanetal.[19].Basedonphylogeographic studies,theseauthorsconfirmedthatcavespecieswere often cryptic and presenting highly restricted distribu- tions. Thesestudiesalsosuggestedthattheir divergence andpotentialspeciationprocessesmayoccurdespitethe presenceof geneflowfromsurface populations.Finally, they concluded that these same studies could provide evidenceforspeciationandadaptiveevolutionwithinthe confinesofcavesystems[19].
Vietbocap, as the other genera associated with the familyPseudochactidae,canbeconsideredasoneofthe most, if not the most basic lineage among known scorpions. If not all authors agree about the precise phylogenetic positionof pseudochactids, they do agree aboutitsbasalposition[7,20].TheVietbocap‘‘populations’’
foundintheThienDuongcaveshowaverysimilardegree ofcaveadaptation,withacompleteregressionofeyesand, inmostcases,averymarkedregressionofthepigmenta- tion. On the other hand, Vietbocap epigean relatives remainunknown.Infact,epigeanelementsofthefamily PseudochactidaearenotknownfromSouth-EastAsia.The originalepigeanancestoroftheVietbocaplineagewasmost certainly an ancient colonizerof underground habitats;
however, the totality of the present known species probably did not derived from a surface ancestor. This atteststoaratheroldprocessofadaptationtosubterra- nean environments. Although available data about the scorpionpopulationsofthedifferentspeciesarestillvery limitedandphylogeneticevidencearestilllacking,itcan beconsideredthatthespeciationprocesstookplaceafter thecolonizationofthesubterraneanhabitatbytheepigean ancestoroftheVietbocaplineage.
Asalreadyexposed,theThienDuongcaveisahugecave with31kmofpassages,inseveralsectors100minheight and 150min width; most present physical parameters insidethecavesuchasairtemperatureandhumiditycan beconsideredrathersimilar.Nevertheless,thegeological historyofthecavesystemisveryoldandmostcertainly knew a number of vicissitudes during geological time, probablycausingcollapsingsituationswiththecreationof local barriers, maybelong enoughin time to allowfull processesofspeciation.Nodatais,however,availableto confirmanyhypothesisinthissense.
Itis difficulttoestimatefromthesolemorphological study of these ‘‘populations’’ of Vietbocap living in the Thien Duong cave what is their precise degree of differentiation. The processes of differentiation and speciation in scorpions are probably rather slow, since thegroupshowslong-termreproductionstrategiesanda low number of generations when compared to other arthropods[21].Consequently,thequestiontobeaddres- sed is: are we faced with species, subspecies or only morphsofalargepolymorphicspecies?Forthreeofthese
populations,aspecificstatusisheresuggestedinassocia- tionwiththeirpossibleallopatricdistribution,thoughthe number of availablespecimens is small toevaluatethe robustnessof theobserveddifferences. Inthis case, the condition of superspecies sensu Mayr [22] could be suggested to the global Vietbocap lineage. The species withineachsub-lineagewouldberepresentedbyallopat- ric, parapatric our weakly sympatric groups, really or potentially inter-sterile in natural conditions [23]. Each oneofthesedifferentspeciescanthereforebedefinedasa Prospecies in the sense of Birula [24]. The main cue, however, remains the discovery and description of an epigeanelementassociatedwithVietbocap,whichhowev- er probably knew a negative selection during the evolutionarytime.
Thepresenceofsyntopicandcloselyrelatedtroglobitic speciesofasamegenusinasamecaveisquiteexceptional.
Molecularapproaches willbenecessary toevaluatethe robustnessoftheobserveddifferencesbetweenthespecies whichhavebeenrecognized.
Disclosureofinterest
The authors declare that they have no competing interest.
Acknowledgements
We wishtoexpress ourthankstoE´lise-Anne Leguin (MNHN,Paris)forthepreparationofthephotosandplates;
toAdrianoKury (MuseuNacional,Rio deJaneiro), Louis Deharveng(MNHN,Paris),andLucienneWilme´ (Missouri Botanical Garden) for their useful comments to the manuscript. The second author is most grateful to the researchprojectoftheVietnamAcademyofScienceand Technology (VAST04.09/16-17) and to the NAFOSTED grant (106NN.06-2015.38), which financially supported himforfieldworks.
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