The　morphology,　morphogenesis　and　molecular　phylogeny　of　the　oxytrichid　ciliate,　Monomicrocaryon　euglenivorum　euglenivorum　(Kahl,　1932)　Foissner,　2016,　isolated　from　freshwater　in　a　seaside　park,　Guangzhou,　China,　were　investigated.　Monomicrocaryon　euglenivorum　euglenivorum　can　be　recognized　as　follows:　caudal　cirri　in　midline　of　body;　dorsal　kinety　1　without　a　one-kinetid-wide　gap;　transverse　cirri　acicular　or　rod-shaped　with　a　fringed　distal　end;　right　marginal　row　commences　at　level　of　buccal　vertex　or　anterior　to　buccal　vertex.　The　main　events　during　binary　fission　are　as　follows:　(1)　the　proter　retains　the　parental　adoral　zone　of　membranelles　entirely;　(2)　frontoventral-transverse　cirral　anlagen　I-VI　are　segmented　in　the　ordinary　pattern　1:3:3:3:4:4　from　left　to　right,　which　form　three　frontal,　four　frontoventral,　one　buccal,　three　postoral　ventral,　two　pretransverse　ventral　and　five　transverse　cirri,　respectively;　(3)　dorsal　morphogenesis　is　in　the　typical　Oxytricha-pattern,　but　fragmentation　of　dorsal　kinety　3　is　indistinct;　and　(4)　three　caudal　cirri　are　formed,　one　at　the　posterior　end　of　each　of　dorsal　kineties　1,　2　and　4.　Phylogenetic　analyses　based　on　SSU　rDNA　sequences　showed　that　M.　euglenivorum　euglenivorum　clustered　with　Kleinstyla　dorsicirrata　and　Heterourosomoida　lanceolata　rather　than　with　its　congener　M.　elegans.　The　genus　Monomicrocaryon　is　not　monophyletic　in　this　study;　however,　its　monophyly　is　not　rejected　by　the　AU　test.