Mae'n fwy na phosibl mai'r teulu yma o bryfaid, y Libellulidae (Cymraeg: teulu'r Picellwyr) ydy'r teulu mwyaf o weision neidr ar wyneb y Ddaear. Mae'n cynnwys yr isdeuluoedd: Corduliidae a'r Macromiidae yn ôl rhai, er bod cryn ddadlau am hyn gan naturiaethwyr. Hyd yn oed heb y ddau isdeulu hyn, mae'r teulu Libellulidae'n dal i gynnwys dros 1,000 o rywogaethau.
Mae eu tiriogaeth yn ymestyn dros wyneb y Ddaear, fwy neu lai, ond ceir ambell un, fel Libellula angelina sy'n hynod o brin. Mae llawer o aelodau'r teulu hwn yn lliwgar eithriadol, neu gyda bandiau ar eu hadenydd. Mae'r genws cysylltiedig, Plathemis yn cynnwys y 'cynffonau gwynion'. Mae'r genws Celithemis yn cynnwys sawl rhywogaeth hynod o liwgar, a welir yn yr Unol Daleithiau. Lliwgar hefyd ydy'r rhywogaethau yn y genera Trithemis a Zenithoptera ac ymhlith y rhai mwyaf cyffredin y mae: Tramea a Pantala.
Mae'r picellwyr canlynol i'w cael yng ngwledydd Prydain:
Delwedd Rhywogaeth Enw Lladin Gwledydd
Picellwr praff Libellula depressa ![src=]()
Cymru ![src=]()
Lloegr 
Picellwr prin Libellula fulva ![src=]()
Lloegr 
Picellwr pedwar nod Libellula quadrimaculata ![src=]()
yr Alban ![src=]()
Cymru ![src=]()
Lloegr 
Picellwr tinddu Orthetrum cancellatum ![src=]()
Cymru ![src=]()
Lloegr 
Picellwr cribog Orthetrum coerulescens ![src=]()
yr Alban ![src=]()
Cymru ![src=]()
Lloegr 
Gwäell scarlad Crocothemis erythraea 
Gwäell ddu Sympetrum danae ![src=]()
yr Alban ![src=]()
Cymru ![src=]()
Lloegr 
Gwäell asgell aur [F] Sympetrum flaveolum 
Gwäell wythien goch Sympetrum fonscolombei ![src=]()
Lloegr 
Gwäell rudd Sympetrum sanguineum ![src=]()
Cymru ![src=]()
Lloegr 
Gwäell gyffredin [G] Sympetrum striolatum ![src=]()
yr Alban ![src=]()
Cymru ![src=]()
Lloegr 
Gwäell yr ucheldir [G] Sympetrum nigrescens ![src=]()
yr Alban 
Gwäell grwydrol Sympetrum vulgatum 
Gwäell resog Sympetrum pedemontanum 
Picellwr wynebwyn Leucorrhinia dubia ![src=]()
yr Alban ![src=]()
Cymru ![src=]()
Lloegr 
Picellwr wynebwyn mawr [H] Leucorrhinia pectoralis 
Y gleider crwydrol [I] [J] Pantala flavescens Genera
Mae Libelluidae yn cynnwys y genera canlynol:
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Acisoma Rambur, 1842 – pintails
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Aethiothemis Martin, 1908
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Aethriamanta Kirby, 1889
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Agrionoptera Brauer, 1864
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Amphithemis Selys, 1891
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Anatya Kirby, 1889
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Anectothemis Fraser, 1954
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Antidythemis Kirby, 1889
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Archaeophlebia Ris, 1909
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Argyrothemis Ris, 1911
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Atoconeura Karsch, 1899
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Atratothemis Wilson, 2005
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Austrothemis Ris, 1909
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Bironides Förster, 1903
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Boninthemis Asahina, 1952
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Brachydiplax Brauer, 1868
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Brachygonia Kirby, 1889
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Brachymesia Kirby, 1889 – tropical pennants
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Brachythemis Brauer, 1868
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Bradinopyga Kirby, 1893
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Brechmorhoga Kirby, 1894 – clubskimmers
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Calophlebia Selys, 1896
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Camacinia Kirby, 1889
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Cannaphila Kirby, 1889 – narrow-winged skimmers
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Celebophlebia Lieftinck, 1936
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Celebothemis Ris, 1909
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Celithemis Hagen, 1861 – pennants
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Chalcostephia Kirby, 1889
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Chalybeothemis Lieftinck, 1933
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Congothemis Fraser, 1953
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Cratilla Kirby, 1900
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Crocothemis Brauer, 1868 – skimmers
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Cyanothemis Ris, 1915
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Dasythemis Karsch, 1889
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Deielia Kirby, 1889
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Diastatops Rambur, 1842
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Diplacina Brauer, 1868
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Diplacodes Kirby, 1889 – perchers
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Dythemis Hagen, 1861 – setwings
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Edonis Needham, 1905
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Elasmothemis Westfall, 1988
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Eleuthemis Ris, 1910
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Elga Ris, 1911
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Epithemis Laidlaw, 1955
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Erythemis Hagen, 1861 – pondhawks
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Erythrodiplax Brauer, 1868 – dragonlets
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Fylgia Kirby, 1889 - white-eyed skimmer
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Garrisonia Peñalva & Costa, 2007
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Hadrothemis Karsch, 1891 – jungle-skimmers
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Hemistigma Kirby, 1889 – pied-spots
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Huonia Förster, 1903
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Hydrobasileus Kirby, 1889
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Hylaeothemis Ris, 1909
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Hypothemis Karsch, 1889
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Idiataphe Cowley, 1934 – metallic pennants
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Indothemis Ris, 1909
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Ladona Needham, 1897
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Lanthanusa Ris, 1909
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Lathrecista Kirby, 1889
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Leucorrhinia Brittinger, 1850 – whitefaces
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Libellula Linnaeus, 1758 (including Plathemis)
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Lokia Ris, 1919
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Lyriothemis Brauer, 1868
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Macrodiplax Brauer, 1868 – marl pennants
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Macrothemis Hagen, 1868 – sylphs
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Malgassophlebia Fraser, 1956
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Miathyria Kirby, 1889 – dashers
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Micrathyria Kirby, 1889 – tropical dashers
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Micromacromia Karsch, 1890
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Microtrigonia Förster, 1903
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Misagria Kirby, 1889
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Nannodiplax Brauer, 1868
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Nannophlebia Selys, 1878
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Nannophya Rambur, 1842
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Nannophyopsis Lieftinck, 1935
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Nannothemis Brauer, 1868 – skimmers
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Neodythemis Karsch, 1889
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Nephepeltia Kirby, 1889
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Nesciothemis Longfield, 1955
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Nesogonia Kirby, 1898
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Nesoxenia Kirby, 1889
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Neurothemis Brauer, 1867
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Nothodiplax Belle, 1984
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Notiothemis Ris, 1919 – forestwatchers
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Notolibellula Theischinger & Watson, 1977
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Oligoclada Karsch, 1890
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Olpogastra Karsch, 1895
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Onychothemis Brauer, 1868
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Orchithemis Brauer, 1878
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Orionothemis Fleck, Hamada & Carvalho, 2009
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Orthemis Hagen, 1861 – tropical king skimmers
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Orthetrum Newman, 1833
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Oxythemis Ris, 1909
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Pachydiplax Brauer, 1868 – blue dasher
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Pacificothemis Asahina, 1940
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Palaeothemis Fraser, 1923
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Palpopleura Rambur, 1842
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Paltothemis Karsch, 1890 – rock skimmers
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Pantala Hagen, 1861 – rainpool gliders
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Parazyxomma Pinhey, 1961
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Perithemis Hagen, 1861 – amberwings
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Phyllothemis Fraser, 1935
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Planiplax Muttkowski, 1910
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Plathemis Hagen, 1861
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Pornothemis Krüger, 1902
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Porpacithemis Fraser, 1954
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Porpax Karsch, 1896
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Potamarcha Karsch, 1890
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Protorthemis Kirby, 1889
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Pseudagrionoptera Ris, 1909
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Pseudoleon Kirby, 1889
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Pseudothemis Kirby, 1889
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Pseudotramea Fraser, 1920
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Raphismia Kirby, 1889
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Rhodopygia Kirby, 1889
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Rhodothemis Ris, 1909
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Rhyothemis Hagen, 1867
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Risiophlebia Cowley, 1934
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Scapanea Kirby, 1889
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Selysiothemis Ris, 1897
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Sleuthemis Fraser, 1951
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Sympetrum Newman, 1833 – meadowhawks, darters
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Tapeinothemis Lieftinck, 1950
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Tauriphila Kirby, 1889 – pasture gliders
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Tetrathemis Brauer, 1868
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Thalassothemis Ris, 1909
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Thermochoria Kirby, 1889
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Thermorthemis Kirby, 1889
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Tholymis Hagen, 1867 – evening skimmers
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Tramea Hagen, 1861 – saddlebags
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Trithemis Brauer, 1868 – dropwings
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Trithetrum Dijkstra & Pilgrim, 2007
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Tyriobapta Kirby, 1889
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Uracis Rambur, 1842
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Urothemis Brauer, 1868
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Viridithemis Fraser, 1960
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Ypirangathemis Santos, 1945
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Zenithoptera Selys, 1869
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Zygonoides Fraser, 1957
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Zygonychidium Lindley, 1970
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Zygonyx Hagen, 1867
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Zyxomma Rambur, 1842
Galeri
Cyfeiriadau
- Silsby, Jill. 2001. Dragonflies of the World. Smithsonian Institution Press, Washington D.C.
Dolennau allanol
Picellwr praff Libellula depressa 
Picellwr prin Libellula fulva .jpg)
Picellwr pedwar nod Libellula quadrimaculata 
Picellwr tinddu Orthetrum cancellatum 
Picellwr cribog Orthetrum coerulescens 
Gwäell scarlad Crocothemis erythraea .jpg)
Gwäell ddu Sympetrum danae .jpg)
Gwäell asgell aur [F] Sympetrum flaveolum 
Gwäell wythien goch Sympetrum fonscolombei 
Gwäell rudd Sympetrum sanguineum .jpg)
Gwäell gyffredin [G] Sympetrum striolatum 
Gwäell yr ucheldir [G] Sympetrum nigrescens _4.jpg)
Gwäell grwydrol Sympetrum vulgatum 
Gwäell resog Sympetrum pedemontanum 
Picellwr wynebwyn Leucorrhinia dubia 
Picellwr wynebwyn mawr [H] Leucorrhinia pectoralis 
Y gleider crwydrol [I] [J] Pantala flavescens 
-_male_W_IMG_0512.jpg)
_W_IMG_1681.jpg)
.jpg)
_-_Male.jpg)
