Table Of ContentQuoderno di Srudie Notizied i StorioN qturole dello Romogno
QuadS. tudNi at.R omagna1,7 s uppl.l:7 -24, giugno2003 tssN1 123-6787
FernandPoe derzani
HYDATICUS SATOI DHOFARENSIS N. SSP.F ROM OMAN
(InsectaC oleopterDa ytiscidae)
Riassunto
[Hydaticus satoi dhofarensis n. ssp. dell'Omanf
Si descrive vrraÍazza geografica di Hydaticus satoiWewalka, 1975, cui si attribuisce lo status
di sottospecie e la denominazrone dt Hydaticus satoi dhofarensls n. ssp. Numerosi esemplari
del nuovo taxon sono stati raccolti nella regione di Dhofar (Oman) dal Dr. Marco Dellacasa del
Museo di Storia naturale e del Territorio dell'Università di Pisa. Alcuni esemplari della mede-
sima provenienza efano stati segnalati in passato (BnaNcuccr, 1980) come Hydaticus satoí
Wewalka, così identificati per le caratteristiched ell'edeago. La disponibilità di materiale più
abbondanteh a consentito di evidenziare alcuni costanti caratteri distintivi, come le dimensioni
maggiori, il corpo più largo e dilatato dopo la metà e il disegno giallo elitrale limitato per lo più
ad un'unica, sottile fascia laterale. La costanza di questi caratteri e la notevole distanza che
separa la popolazione del Dhofar dal rimanente areale di H.satoi, assente da Iran e Pakistan
meridionale, suggeriscono trattarsi di una forma endemica, evolutasi a causa dell'isolamento
geografico. La sottospecie è confrontata con la forma tipica e con alcune specie vicine.
Abstract
Hydatícus satoi dhofarensrs n. ssp. is described from the Dhofar region, Oman, and compared
with the nominal form and some allied species.
Key words: Hydatícus satoi dhofarensls, Dhofaq Oman, Dytiscidae.
Introduction
Dr. Marco Dellacasa,o f the Natural History Museum, Pisa University, kindly
submitteda collectiono f 35 waterb eetless ampledd uring a trip to Oman,D hofar
region,i n October2 002.
The Dhofar region is subdividedi nto 9 provinces( wilayats).I ts climate is
dramaticallyd ifferentt o the resto f Omand uet o the effectso f the monsoonr ains
(khareef)w hich arrive during the summerm onths,c reatingh umidity and modera-
te temperatureso f around3 00C . As a consequencet,h e areab ecomesl ush and
green,w ith waterfallsa ndr ivers feedingt he surroundingp asturesT. he mountain
ridge,w hich receivesth e mostr ain, stretchesfo r 400 km from eastt o west.D urins
t7
the khareef, springs gush forth and provide plentiful water supplies for much of
the rest ofthe year. The fresh greeneryi s ideal for cattle graziÍtg,a nd livestock
rearingi s an importanto ccupationin the arear.
Climates upportsth e survivalo fplants anda nimalsf orming anu niquee cosystem,
a relict of the time when Arabia was not so arid and deserta s it is today. The
uniquee cosystema ndt he high numbero f endemismjsu stify the greatn aturalistic
interesot f the Dhofarr egion.
The small collection of water beetlesr eceived for identification comprises4
specimenso f Gyrinidae,23 Dytiscidaea nd 3 Hydrophilidae.T he most abundant
speciesis a distinctive,p ossiblye ndemicH ydaticusL each,I 81 7, dealtw ith here
below; the othersa re widely distributeds pecies.B naNcucct( 1980) reported4
exx.o f Hydaticuss atoiW ewalka,I 9l5 fromOman,D hofarregion,O ctober1 979,
leg. Larsen,a nd noticedt heir reducedy ellow elytral pattern.T he assignmentto
Hydaticuss atoi was duet o the shapeo f penis.S incem ore specimensw ere made
availablef or studyb y Dellacasa'sc ollection,i t becamep ossiblet o outline a few
constantd ifferencesb etweent he type form of Hydaticus satoi and the taxon from
Dhofar.N o doubtst he latter is closet o the former and possiblyd erivesf rom an
original stock of that species,c ut off by withering climate.A ctually Hydaticus
satoiis not reportedf rom both southernP akistana nd Iran, so therei s a wide gap
of arid countriesb etweent he distributiona reao f Hydaticuss atoi f . typ. (India and
eastward)a nd the Dhofar region of Oman. Whether the endemic taxon is a
geographicarl ace of H. satoi or has developedi nto a different species,it is an
openq uestion.H owevera reasonablea ssumptionis to assigni t subspecifics tatus.
Hydaticus satoí dhofurensl's n. ssp.
Type material
Hydaticuss atoi dhofarensisn . ssp. (23 exx.)
6 66 and8 QQ :"Ain Sanahawq1, 7o08,6N4 - 54'10,85'E,m 130,5 .IX.2002";4
66 and2 ??: "WadiH inna,1 7o03,20'N- 54"36,56'Em, 350,1 0.IX.2002";1
"Wadi
Q: Darbat,b asec ascatafb elow waterfall],H g light, 11.IX.2002";I é and
I Q: "JabalS amhanE, of Hyoor,1 7"07,88'N- 54'43,99'E,m 1350,1 4.IX.2002".
Holotype:a males pecimenla belled" Ain Sanahawq1,7 o08,6N4 - 54o10,85E' , m
130,5 .IX.2002"d epositedin the NaturalH istory Museumo f Pisa( Museod i Sto-
ria naturalee del Territoriod ell'Universitàd i Pisa).T he remaining2 2 specimens
arep aratlpes.T hey ared epositedin the Natural History Museumo f Pisa,i n author's
collection,i n coll. SaverioR occhi( Florence)a ndc oll. GùntherW ewalka( Vienna).
Referencem aterial
Hydaticuss atoi satoi Wewalka,1 975( 30 exx.)
' This paragraphw as downloadedf rom an ofhcial site of Dhofar govemment on the web
18
Figs. 1-4 - Median lobe ofthe aedeagus( a: side view, b: dorsal view): l. Hydaticus satoi dhofarensis n. ssp.
[Oman]; 2. Hydaticus satol satol Wewalka [Myanmar]; 3. Hydaticus vitîatus vittatus (Fabicius) [India, Assam];
4. Hydaticus víttatus vittatus (Fabricius) [Japan, Okinawa].
r9
1 j: "Bhutan,D orjee Kandu, Dorjula 3100 m, 2.IX.1976.d et. M.BranatccT";2
"Nat.
i: Hist.M useumB aselB hutanE xpeditionl 972,Paro2 300m . 28.IV.|?1.I972
"Nepal
det. Wewalka"; | 6'. m 2000 NagarcotV II.1995 leg. Ammosov"; 1 i:
"IndiaAssam
ShillongK hasiH ills leg. Sircar1 968";3 63 and3 ??: é South
India, Madras State,C oimbatore1 400 ft. XI.l974leg. T.R.S.N athan"; Mysore
"South
State4 Q8 : IndiaC oorgD ist. Mercara4 000f t.V.l9l3leg. T.R.S.N athan";
"South
1 é and I t: India Mysore State,S himogaD ist. Agumbe Chat 2000 ft.
"South
V.l974leg. T.R.S.N athan"; I Q: India, Kerala State,T rivandrumD ist.
"N.
PoonM udi Range3 000f t. V.19721egT. .R.S.N athan";1 é and 1 !: Myanmar,
"Mus.
Putao 500 m 23.YII.I998 leg. S. Murzin & V. Siniaev"; | $: Pragense
"North
Tenasserim[M yanmar] col. Helfer, det. Wewalka"; | 6 and I Q: Thailand,
Mae Taman,5 0 Km NW ChiangM ai, 25.VI - 4.VII.1998,l eg. E. Kuèera"; I i
and I t: "Laos north, 15 Km NW LouangN amtha2 1"07.5'N - 101'21.0'E , alt.
"Laos
750+100m l3-24.Y.1997E . Jendek& O. Sau5ale g|';2 $$ and3 ??:
north2 0 Km NW LouangN amtha2 1"09.2'N - 101'18.7E' alt.900+100m 5-
Il.V.l99l E. Jendek& O. Sau5ale g.,d et.S . Rocchi".
Hydaticus vittatus vittatus (Fabricius, 1775)
Only figured specimensa re listed.
"India,
I i : Assam,6 mi N of Tinsukia,9 .IV.l 94 4 DF.Hardy,d et.W ewalka flength
12.53m ml (Figs.3 and5 );
"Japan,
1 i: Okinawa,I shigakijimaI s., 15-20.XIL1987,l eg. Y. & T. Abe, det.
T.Abe" fiength1 3.14m m] (Fig.a ).
Description
The following descriptionp oints out principally the differencesb etween the
subspeciesa nd the nominal form of Hydaticus satoi Wewalka, I 975.
Size
Hydaticus satoi dhofarenslsn . ssp.
Length I 3.4 - 15 .1 0 mm; meanl ength1 4.I 9 mm (o : 0.43),m eanr atio of width to
length0 .567( o: 0.0077).
The holotypei s 14.55m m in lengtha nd 8.25m m in width, ratio of width to length
0.567.
Hydaticus satoi satoi Wewalka, 1975
Literatured ata:l ength 12 - 14 mm (Wnwerre,1975).
Referencem aterial:l ength 12.37- 13.95m m, meanl ength 13.35m m (o:0.462);
meanr atio of width to length0 .552( o : 0.0084).
Shape
The subspeciesd hofarensrsi s broader and less tapering in front and behind than
the nominal form. It is broadestb ehind the middle. The ratio of width to length is
higher in dhofarensls( broaderb ody), usually higher than 0.56, and is lower than
0.56 in the nominal form, as a rule.
20
More details on size and shapea re given in the following table.
, body length (mm) : ratio of *iatt to terrgrt
;s;òsii .d.,dud .fnhtàf;u.oif lJ,bJ;eufa;;r;nre;;et,inii,n;ù;(;Qyisi'i-; sÀ* i s Gi ,ili,til:i ,i1 ;ttjîjz3i t ii..1' i rr1 1jr1^.j3oi.e.:4)45. -, iii,ii 4 r1i iri+) 54..ir...OuSr5o s 5 jjIi: i i t1 irj4c43...te.Jis9aeU 9 -iii1 i. ..i..fqó3446 0 0 ' _jiri ...,.s55.jjj5656l' 03 30 ii.;ii:.... 5sS5s7ig8di7-r3':" iii',i.:..,55Ss.566ao9ò6Oa j 'iij,....o0i0OO0oòo6iSijro4ó+
Table1 .B ody lengtha ndr atio of width to lengthm easuredin 30 exx. of Hydaticus
satoi satoi and23 exx. of Hydaticus satoi dhofarensisn . ssp.
The table gives the results of measurementsa nd some statisticala rrangementsA.
self explaining representationo f the differences in length and ratio of width to
length betweens atoi f. typ. and ssp.d hofarenszsis shown in fig. 8. In spite of a
moderateo verlapping,t he two subspeciesfo rm different setso f points.
Colour pattern
upper sideb lackw ith yellow pattern.H eady ellow in front andb lackb ehind,a s in
-l
1:l
Figs. 5-7 - Colour pattem of the dorsal side: 5. Hydaticus yiîîotus vitfaîus (Fabricius) [India, Assam];
Hydaticus saîoi saîoi Wewalka [Myanmar]; 7 Hydaticus satoi dhofarensisn . ssp. [Oman].
2l
most specieso f fhe vittatusg roup.P ronotumw idely yellow at sidesa nd black at
the middle. The border line betweenb lack and yellow is slightly angulatea t the
middle (Fig. 7) as in the type form (Fig. 6).
The yellow bandso f elytra are narrowera nd shortert han in H. satoi satoi. The
outerb and attainst he margin at basea nd is submarginabl ehind,e xtendings hort
beyondt he middle of the elytral length as a rule, exceptf or a few specimensi,n
which the outerb anda pproachetsh ep reapicaly ellow spot.T he outerb andi s very
narrowi n melanics pecimensb, ut neverm issing.T he inner (discal)b andi s either
absento r reducedt o a short and narrow sub-basasl tripe,n ot connectedt o the
outerb and.P reapicayl ellow spotsa lwaysd etectablea, lsoi n melanics pecimens.
Undersided ark brown with yellow prosternapl rocess;a nteriorl egsa ndm esofemurs
yellow; intermediateti biaea ndt arsil ight brown,p osteriorl egsd arkb rown; setose
fields of metatarsiw ith long black setae,p aler at apex; palpi and basalh alf of
antennaey ellow.
Puncturation
The dorsals urfaceis coveredb y a densea ndm inutep uncturationw ith interspersed
larger punctures,p rincipally at the base of elytra. The submarginalr ows of
punctureso f pronotuma ndt he elytralr owsa sw ell ast he sculptureo f theu nderside
do not presentd ifferentialc haracters.
Sexualc haracters
Male. The medianl obeso f the aedeagusin satoi f. typ. and ssp.d hofarensisa re
alike (Figs. I and2).A few minor differencesc anb e observedin somes pecimens,
but they aren ot suitablef or taxonomicp urpose.T he secondarys exualc haracters
of both the nominal form and the subspecieas re alike.
Female.D isc of pronotumw ith two latero-basacl orrugatedf ields, not extending
to the yellow areas.G enitalp iecesn ot studied.
Distribution.O nly known from the Dhofar region,O man.
Biology.T he new taxonw asc ollectedf rom sidep oolso f streamsa nds prings,a nd
at light.
Discussion
Hydaticuss atoi dhofarensisn . ssp.c an be identified at sight becauseo f its size,
the body shapea ndt he colourp attern.A s for colour,d ark specimenso f Hydaticus
vittatus andH ydaticusb ipunctatusW ehncke,l 8l6 (seeW nwarx.d,1 975:f igs. 6
and l1) canb e mistakenf or sqtoi dhofarensisb ut they are smallera s a rule. Dark
specimenso f satoi dhofarensish ave a resemblancew ith Hydaticus daemeli
Wehncke,1 876f rom Australia,w hich is similar in sizea nd colour,b ut differs in
other characters.
The subspecieasn dt hen ominalf orm arec loselyr elatedt o othert axao f thevittatus
groupw ith a similar aedeagusp, rincipallyH ydqticusv ittqtus( Fabricius),É lydaticus
22
majorRégimbart,1 899a ndHydaticusa rabicusG uignot,1 951.T he closests pecies
is Hydaticusv ittatus( Fabricius),b ut its medianl obe of the aedeagusis narrower
in lateral view and pointed at apex in dorsal view (Figs. 3 and,4 ), while it is
wideneda pically in satoi.
H. vittatus andH . major were revisedb y Wrwarre (1915).H ydaticusa rabicus
Guignot,d escribedo n two malesf rom Hadramaut( GutcNor,1 95l ), was revised
and figuredb y BneNcuccr( 1981).
This speciesis geographicallyc loset o H. satoi dhofarensisa nd is similar in size.
The principald ifferencesli e in the colourp atterno f elytraa ndt he narrowerp enis
of arabicus,in sidev iew2.
The remaining memberso f the vittatus group and the Afro-Malagasy Hydaticus
bivittatusL aported e Castelnau1, 835h ave afairly differents hapeo f the aedeagus
and cannotb e confusedw ilh satoi.
Waterb eetlesf ound in associationw ifh Hydaticuss atoi dhofarensisn . ssp.
Fig. 8 - Length and ratio ofwidth to length of H. satoi sctoi (white triangles) and H. satoi dhofarensis (black
triangles).
2T he median lobe of the aedeagusin H. satoi and its allied is about 3 mm long, however according
tothescale-barbyB neNcuccr(1981),thepenisoflaLr abicusisapproximatelyhalfaslongasin
other specìes.
ZJ
Fam. Gyrinidae
Dineutusa ereLrKs lug, 1834
2 exx. "Wadi Hinna, 17"03,20'N- 54'36,56'E , m 350, 10.IX.2002"; I ex. "Wadi
Darbat,b elowR d.49, 17o03,1N6 - 54'25,60F .,1.IX.2002";1 ex." WadiD arbat,
basec ascata[ below waterfall],H g light, 11.IX.2002".
Fam.D ytiscidae
Hyphydrusp ictus Klug, 1834
I ex." Ain Sanahawq1, 7"08,64N - 54"10,85E' , m 130,5 .IX.2002":1e x. "Wadi
Hinna,1 7"03,20'N- 54'36,56'E , m 350, 10.IX.2002".
Hydroglyphusl : Guignotus)m ajor (Sharp,1 882)
"Jabal
I ex. SamhanE, of Hyoor,1 7o07,88'N- 54'43,99'E,m 1350,1 4.IX.2002".
Eretess ticticus( Linnaeus,1 767)s ensuM rI-r-en(2 002)
"Al
1 ex. Mughsayie nvir.,1 6"53,01N - 53o46,418 ,6.IX.2002".
Cybistert ripunctatusa fricanusL aported e Castelnau,1 835
"Wadi
1 ex. Hinna, 17"03,20'N- 54"36,56E' . m 350. 10jX.2002".
Fam.H ydrophilidae
Temnopteruasc uleatusS olier,I 834
"Wadi
1 ex. DarbaI,b elowR d. 49, 17"03,16N - 54o25,608,j .IX.2002"; 2 exx.
"Wadi
Darbat,b asec ascata[ below waterfall],H g light, ll.IX.2002".
Acknowledgement
Thanks are due to Dr. Marco Dellacasa( Pisa)w ho kindly lent the material for
identificationa nd supportedth e studyw ith informationa nd advice.
References
BnaNcuccMr ., 1980- Insectso f SaudAi rabia.c oleopteraF: am.H atiplidaeD, ytiscidae,
GyrinidaeP.a rt2.F aunao f SaudAi rabia,2:102-111.
BnaNcucMcr. , 1981- Insectos f SaudAi rabiac. oleopteraF:a m.D ytiscidaep.a rl3 .F auna
oJS audAi rabia,3:2 27-230.
GutcNorF ., 195I - Hydaticusn ouveauxd e la collectionR égimbartR. evueF ranqaise
d'Entomologie1,8 :2 1-24.
Mtt-ronK .B.,2 002- Revisiono f theG enuEs retesL aporte1, 833( ColeopterDa:y tiscidae).
AquaticIn sects2, 4 (4):2 47- 212 .
wewerxa.G ., 1975- Revisiond er Artengrupped esH ydaticusv ittatus( Fabricius).
KoleopterologischReu ndsc hau,5 2:8 7-I 00.
Author's address:
FernandoP ederzani
via Landoni,3 5 I-48100R avenna
e- ma i I : p ed [email protected]
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