MacrothrixMacrothrix is a genus of water fleas in the family Macrothricidae.The genus was described in 1843 by William Baird, and has a cosmopolitan distribution.SpeciesThere are 54 valid species assigned to the genus Macrothrix, including:Macrothrix acutirostris Macrothrix agsensis Macrothrix albuferae Macrothrix atahualpa Macrothrix boergeni Macrothrix brandorffi Macrothrix brevicornis Macrothrix breviseta Macrothrix burstalis Macrothrix camjatae Macrothrix capensis Macrothrix carinata Macrothrix dadayi Macrothrix elegans Macrothrix flabelligera Macrothrix flagellata Macrothrix gauthieri Macrothrix hardingi Macrothrix hirsuticornis Macrothrix hystrix Macrothrix indistincta Macrothrix laticornis Macrothrix longiseta Macrothrix magna Macrothrix malaysiensis Macrothrix marthae Macrothrix mexicanus Macrothrix montana Macrothrix novamexicana Macrothrix odiosa Macrothrix oviformis Macrothrix paulensis Macrothrix pectinata Macrothrix pennigera Macrothrix pholpunthini Macrothrix pseudospinosa Macrothrix rectirostris Macrothrix rosea Macrothrix ruehei Macrothrix sarsi Macrothrix schauinslandi Macrothrix shadini Macrothrix sierrafriatensis Macrothrix sioli Macrothrix smirnovi Macrothrix spinosa Macrothrix superaculeata Macrothrix tabrizensis Macrothrix timmsi Macrothrix tobaensis Macrothrix tripectinata Macrothrix triserialis Macrothrix vietnamensis ''Macrothrix williamsi''