Description
*Newly elevated or recognized taxa compared to Small and Lynn (1981 , 1985) . , KEYS 395 KEYS TO TAXA The introductory keys that follow are designed to allow the user to place an unknown ciliate within a certain group, usually at the level of class or subclass. This will then lead to keys that w iII permit identification to genus within one of the many families of ciliates. The characteristics utilized in the keys are not necessarily the major criteria upon which the various systematic categories have been founded. While body shape, arrangement of, and/or presence or absence of cilia, and presence or absence of a cytostome have been used as key characteristics , frequently ultrastructural features of the kinetid or the ultrastructure of the cytostomal area coupled with various basic morphogenetic attributes are the most important systematic criteria for actually grouping ciliates into their proper taxa (Small and Lynn, 1981) . If one were to devise a completely "natural" set of keys, these keys would require the use of ultrastructural features . The first key, Key to the Ciliates, should permit one to place the unknown ciliate into a particular group, ranging from genus to class. Following this key is a key relying on the color of the ciliate , Key to Some Common, Colored Ciliates, if color seems a particularly striking feature. Finally, if the shape seems especially different, the user might try the Key to Common Ciliates by Shapes. These keys should take the reader to the subsections within the Keys to the Classes , where there are further keys allowing identification to genus. We have restricted our treatment to selected genera, most having been redescribed or described using silver-staining techniques. Thus , not all described genera are included in these keys. Other keys and guides to genera of freshwater ciliates are provided by Curds (1982) , Curds et al. (1983), Foissner et al. (1991, 1992, 1994, 1995) , and Patterson ( 1 992). Many genera have not been redescribed since Kahl (1930-1935), whose monograph should be consulted for the descriptions of many species. Species descriptions can also be found by refer ring to the sources of the many illustrations in this chapter. The user must be forewarned that the illustrations used are given as examples of genera only ; that is, the figures illustrate one or several species considered typical of the genus but do not represent the array of species found in some genera. The user should not attempt to identify a species using these keys ; rather, reference should be made to the primary literature or to Kahl (1930-1935). The sizes of the included taxa are meant only as a guide ; size itself can be a very variable characteristic , both among and within species. NOTE. All scale-bars have their smallest division as 25 IJm . bLM 1. With one or more (mostly more) feeding tentacles and without a true cytostome or cytopharynx ... ... .... ClassPhyllopharyngea ... .... ..... . ... .... . (Figs .1,2) Subclass Suctoria .. ... ........ ................ ... ... .. Class Litostomat ... .... .. (Fig. 3) Family Actinobolinidae 1'. Without tentacles .. .. .... .... .......... .. ... ......... 2. Apparently without a cytostome and without a cytopharynx ; may be attached or unattached ; sometimes endosymbiotic ..... .... ... .. ..... .. ......... 2' . With a cytopharynx and/or cytostome .... ... .. .. 6 3. Free-living forms ...... .......... ......... .. . ... ..... . 3' . Not free-living forms ; endosymbionts ........... 5 4. Flattened , ribbon-like forms ; psammo- bionts , with attached rod-shaped bacteria on the non-ciliated surface ; brackish or marine .. . .... .. .. .......... ... ..... .. ..... Class Karyorel .. . ........ .. (Figs . 4,5) Order Protostomatida 4' . Flattened, ribbon-like forms with rows of toxicysts inserted along one margin of the ora I area (actually, there is a slit-shaped cytostome adjacent to the toxi .... ... .............. ..... .... ..... .. . Class Litostom ..... .. ... . (Figs . 6,7) Order Pleurostomatida 5. Small , pyriform ciliates with mostly bipolar kineties; with one surface devoid of an oral architecture; found in the hemocoel of PHORA, KEYS arthropods or free-living ............. ....... Class Oligohymenophorea (Fig . 8) .... ....... ... ... . .... .. .......... .... .. Family Curimostomatidae) ea ........ 2 . 3 . ... 4 ictea cysts) atea C 5' . Variously shaped (but frequently cylindrical) ciliates with many kineties ; often found in the lumen of digestive tracts of many annelids and some molluscs .. Class Oligohymenophorea ............... (Figs. 9,10) Subclass Astomatia 6. Sessile ciliates, i. e., attached to a substrate by an extra-cellular product or cellular process , such as a lorica and/or contractile or non- contractile stalk or stalk-like process .. . ..... 7 6' . Free-swimming, non-sessile , sedentary ciliates attached within lorica; mostly planktonic ..... ......... ..... ... ..... .... .. ....... ... .. ..... .. 14 6" . Free-swimming, non-sessile , non- sedentary ciliates ... .... ..... ... ... ....... .. ... ..... ... ... 18 7. Loricate ciliates (non-planktonic, except those attached to planktonic invertebrate hosts) .... ........ .... .... .. ......... .. ... .. .. ... .. .... .. ... ... 7'. Ciliates lacking a lorica but with a secreted hold-fast structure , which may partially envelop the body ... .... .......... .... ...... .. ...... ... .. .. 15 8. Loricate organisms with cilia; lorica may or may not bear a stalk, or the lorica itself may bear a stalk-like extension for attachment to sub-strate ... ....... ... .. ... .... .. ... .. ... ... ....... ..... ..... . 8' . Loricate ciliates without cilia (except during division or other morphogenetic events) ; with suctorial tentacles (see 1') ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Class Phyllopharyn ..... .. .. ...... (Figs . 11 , 12) Subclass Suctoria 9. Ciliates free to move within lorica ; somatic cell surface with cilia ; specialized oral c iIi a ·············· ······· ···· ········· ···· ... ..... .. ...... .. ... ... .. . 9' . Ciliates not free to move within lorica but attached to lorica .. ... .... Class Spirotrichea .. ............... (Figs. 13,14) Order Tintinnida 10. Oral ciliature at the anterior apex, or the cytostome appears to be anterior apical ...... ....... .... ... ...... .... ... ..... ...... ..... ... ........ 10' . Oral region clearly removed from this anterior position .. .. ...... ... ... ........ .... ..... .. .. .. ... 12 11. Oral ciliature at anterior end of cell without in-pocketing of the cell surface surrounding the cytostome .... ....... ...... Class Prostomatea .. ... .. ....... .... (Fig . 15) Family Metacystidae ... ......... ..... .............. ... ...... ....... Class Colpodea ... .. .. . (Fig . 16) Family Cyrtolophosididae ILIOPHORA, KEYS 397 11'. Cytostome at base of vestibulum ; lorica frequently arborescent. ....... .Class Colpodea .... .. ..... .......... (Fig. 17) Family Marynidae 12. Cytostome of loricate ciliate situated in a shallow ventral oral cavity .. .... ......... .... 13 .... 8 148 ! . 9 ! .... .... ....... . gea .... 10 and 398 CILIOPHORA, KEYS 12'. Cytostome of loricate c oral cavity ; ciliate's during observation so t free-swimming ; ciliate shaped with many rows o large set of oral polyk non-attached end and le 18 cavity proper .... ... .. .. ... . ....... ... ' -.. 12" . Attachment of ciliate . b1 •• - t:. surface of the body; wi 19 -::::= -=?"" . ciliated; prominent seri leading to cytostome at ... .. .... .......... .... .... (Figs . 19,20 13. Cytostome at base of sha few oral polykinetids an parts ..... ..... ...... .... .. . (Fig . 16) F 13'. With oral polykinetids paroral ciliature ... .. ... ... ... ... ... . . .. (Fig. 21) Family Caly 13". Cytostome with shallow spiralling serial oral p ..... .... .. .... . .. ...... ..... .. ...... ( 14. Attachment of cilia process (nonkinetosoma site frequently on the . . . . . . . . . . . ..... .. .... .... .. 14'. Attachment of th at the base of the lor accompanied by a stalk ciliate with cytostome infundibulum ; with pr ciliation that include polykinetid and the h a trophont , devoid of . . . . . . . . . . . (Figs. 25 ,26) Su 15. Hold-fast structure around the base of att flattened aboral proce iliate situated in deep, attachment easily altered hat it may become s may be trumpet- f somatic cilia and a inetids coursing over ading into the oral ... .... Class Heterotrichea ... (Fig. 18) Family Stentoridae appears to be a broad th somatic surfaces al oral polykinetids base of deep oral funnel ... .. .... . ... .... Class Heterotrichea ) Family Folliculinidae llow oral cavity with d paroral of two . ... .. ....... ...... ... Class Colpodea amily Cyrtolophosididae and large velar .. ....... ... .. ... .... ... .. ... ... .. .. . .. . . . . . . . . . . Class Oligohymenophorea ptotrichidae oral cavity and olykinetids ... ... .... .. .. .. .. . .. . . . .. . . .. . . . . . . . .. Class Spirotrichea te to lorica by peduncular l) with attachment side of the lorica .. . . . . . . . . . . . . . . . . . . . . . . . . . .. Class Spirotrichea (Figs . 23 ,24) Order Tintinnida e ciliate to the lorica is ica; may/may not be or stalk-like process ; at the base of deep ominent peristomal s one continuous oral aplokinety or paroral ; as somatic ciliation ........ . . . . . . . . . . . . . . Class Oligohymenophorea bclass Peritrichia is secreted as a ring achment or appears as ss .... ........ ...... ..... ... .... 16 15' . Hold-fast structure is a secreted stalk or stalk-like process that partially envelops the body ...... .... ..... ........ .... ............ 16. Without any ci lia (except during division or other morphogenetic events); with conical- shaped suctorial tentacles arranged in bundles around periphery of the non-attached portion of the body ; non-contractile (see 1) ... ....... . ........ .......... ......... . .Class Phyllopharyn ..... ....... .. (Figs . 27 ,28) Subclass Suctoria 16'. With obvious peristomal cilia present (see 14') ; body contractile ; ectosymbiotic usually .. ...... .... .... .... ... .. Class Oligohymenoph ... .... .. . (Figs . 29 ,30) Subclass Peritrichia 17. With sparse somatic ciliation restricted to surface bearing the oral area ; body non- contractile ; usually ectosymbionts of cru stacea . .. . ... ..... Class Phyllopharyngea (F igs. 31 ,32)Subclass Chonotrichia 17'. With obvious peristomal ciliature (see 1 4') ; body contractile ................ ...... ....... .. ................ ... ...... Class Oligohymenophorea .. . .. .... (Figs . 33 ,34) Subclass Peritrichia 18. With oral cil iature , cytost cytopharynx positioned on or near the anterior or posterior apex ; may or may not have anterior cytoplasmic projection ..... .... 19 18' . Oral structures not positioned near an apex , but rather ventral. .. .............. ... ... ... 19. Oral structures at or on the surface; if in doubt, the cavity-like area preceding the cytostome does not kinetids .. ... ...... ... ..... ... ....... ... . 19' . With an oral cavity or vestibulum whose walls bear specialized , often densely packed , kinetid files ; cytostome at its base ; may be endosymb iotic ... . . . . . . . . . . . . . . . (Figs . 35 ,36) Class .. .... ... .. .. .. ....... ...... SubclassTricho ... ... ... .... .. .. .... ... ... ..... . .. . . ... ... .. ...... ..... (Fig . 37) Family Sonderi 20 . Oral area at anterior end ; living in sandy or sil ty brackish or marine benthos ; tube -I ike or ribbon-like body ; somatic cilia variable ; oral ciliature inconspicuous or absent ........ ... ... ..... ..... . .Class Karyor ....... ....(Fig . 38) Family Trachelocercidae CILIOPHORA, KEYS 399 ........ ..... .. .. ... ... 17 gea orea ... ........ . ome , or ... ...... .... 21 bear cilia or ... .. .............. ... 20 .... ... ........... .... ..... ... .... .. . Litostomatea stomatia ... Class Plagiopylea idae tion elictea 400 CILIOPHORA, KEYS 20 '. Cytostome (or cytostomal-cyto-pharyngeal structures) at the anterior pole ; coronal ciliature ; clavate cilia located within kineties ; somatic ciliation variable , may be as rings or bands ; toxicysts within the borders of the coronal ciliature ..... .. .. .. Class Litostomatea ... .... .... .. (Figs. 39 , 40) Subclass Haptoria 20 ". Cytostome (or cytostomal-cytopharyngeal structures) at the anterior pole ; without clavate cilia ; most kineties bipolar ; without brosse or toxicysts ; may be endosymb iotic ... .. . ... ..... .. ................. .... .... ... .Class Prostomatea .......... .... .. .. .. (Fig . 41 ) Order Prostomatida ................. ... ..... ........... .Class Litostomatea ... .... .. (Fig . 42) Suborder Archistomatina 20"' . Coronal ciliature and cytostome near the ventral anterior ; brosse poly-kinetids may interrupt the coronal ciliature as they extend from anterior pole posteriad ; toxicysts near brosse , and always external to coronal ciliature sensu stricto ; somatic kineties terminating near brosse , often forming suture line ... ........... ... ... ...... ....... Class Prostomatea .... .... .... (Figs . 43,44) Order Prorodontida 21 . With slit-like area for ingestion (but no permanent cytostome) placed along one edge of flattened ribbon-like body and extending up to 1/2 body length ; anterior end frequently curved ; toxicysts inserted along one edge; external to toxicysts , dikinetids at bases of coronal ciliature ; frequently large species as predators of peri trichs ..Ciass Litostomatea ........ .. ... .. (Figs . 45 ,46) Subclass Haptoria 21' . Cytostome not slit-like ; pericytostomal region removed from anterior and accompanied by specialized oral ciliature 22 . Specialized oral ciliature confined to region adjacent to the cytostome (e .g. Tetrahymena ; I 47 22 '. Specialized oral ciliature not so confined but extending out over the body surface (e .g ., Nassula, Stentor, peritrichs; Figs . 4 8-5 0) 23 . Oral depression , a densely ciliated cavity w ith no distinct oral polykinetids ; either ventral or ventra-posterior in position ; may be endosymbiotic ..... ......... ... .. .... .. ..... .... ... ... .... .... ... ... ... .. ........... .. .. . (Fig . 51) Class Plagiopylea ...... .... .. .... .. ......... ........... Class Litostomatea .. .... .. . (Fig. 52 , 53) Order Vestibuliferida 23' . Oral ciliature not as above ; with ventral or ventra -posterior oral areas .... .......... ...... .. 24 24. With conspicuous oral ciliature that some- times becomes apparent only when the ciliate stops movement. ..... ..... .......... ..... .... .... .. ..... 25 24'. With inconspicuous oral ciliature .. .... .. .... 30 25. Oral ciliature becomes obvious when ciliate ceases movement; velar ciliature of paroral dikinetids is then extended ...... .... .... ... .... ..... .. ... . ..... .... .. .. .. . ....... .. Class Oligohymenophorea ... .... (Figs . 54 ,55)0rder Pleuronematida 25'. Conspicuous ciliature otherwise .... ... ...... 26 26. Oral cavity embellished by conspicuous cilia (or infraciliature) on left and right sides ; with right oral dikinetids; without serial oral polykinetids ... ............. ...... ........ .............. ..... 27 26' . With conspicuous polykinetids forming a serial left oral polykinetid zone, frequently extending anteriad to circumscribe a peristomal field (e.g. Class Colpodea; Class Spirotrichea; Class Heterotrichea; Figs . 56- 58} ....... ... ......... .. .... .... ... ... ... .. .. .. .... .... ... ... .... 29 26" .With obvious peristomal cilia restricted to adoral band bordering the peristome (see 14') ; may be ecto- or endosymbiotic ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . Class Oligohymenophorea .. .. ... . (Figs . 59, 60) Subclass Peritrichia 27 . Frequently with a large vacuolar space underlying these oral cilia ........ .... ........ . .. . .. . . . . . . . . . . . . . .. .. . .. Class Oligohymenophorea ...... .. (Fig. 61) Subclass Hymenostomatia 27' . Without underlying vacuolar space .. . ..... .. . 28 28 . Oral area comprises more than 2/3 ventral surface ........ ... ..... ... .. ..... . Class Nassophorea ............ ... .(Fig. 62) Family Lembadionidae CILIOPHORA, KEYS .. : : : .. ·· · .·.·. .··>:·>- 28'. Oral area comprises less than 1/2 ventral surface ..(Fig. . . . . . . . . . . . . . . . . . . . . . . . . Cl 29 . With conspicuous left and/or preoral serial oral polykinetids ... .. .... .... .... ... .... . . . . . . . . . . . (Figs. 64-67) Class Spirotr ..... ....... .. ...... .. (Figs. 56 ,68) Class C 29' . With conspicuous right ciliature ........ ..... ......... .. ..... ..... . . . . . . . . . .. (Figs . 69 , 70) Class Karyo .. ...... . ..... ..... (Fig. 71) Class Heterotri .... .. ...... ..... .. .. ..... Class Oligohymen ..... .... .. (Fig. 72) Subclass Scuticociliatia ........ .. .... ... ... ... .... ... (Fig. 73) C NOTE: The majority of genera keyed belowthis point will have inconspicuous mouthparts. Certain identification of these genera and proper use of this key will require that the specimens be stained by the silver-proteinate or protargol silver-staining procedure . b 9<9 30 . Somatic kinetids of most somatic kineties with paired kinetosomes , with or without cilia on both kineto-somes ....... .... ......... .... 30' . Somatic kinetids of most somatic kineties with single kinetosomes , with or without cilia ... ... .. ........... ...... ..... ....... 30" . Somatic polykinetids , either in linear or polygonal arrays( Figs . 74 ,75,77) ....... ... ..... .. ..... .. .... .. ... ....... ... ... Cl .. ..... .... .... ..... (Figs . 76) Class Nasso ..... ..... .. ... ....... (Fig. 78) Class Plagi 31. Somatic kinetids with paired kineto-somes accompanied by an obvious fiber such as basal microtubules , postciliary microtubular fiber, kinetosdesma, or transverse microtubular fiber ; fiber may be as wide in cross-section as the paired kinetosomes ... . 32 31'. Such a fiber absent or not conspicuous ... ... 34 32. Kinetosome pair oriented obliquely to the fiber ; the fibril from each pair arises at the posterior kinetosome and extends posteriad to insert in the postciliary microtubular fiber (Figs. 79 ,80) ... ...... ... .Class Karyorelic CILIOPHORA, KEYS 63) .... .... ... .... .. .. .... ... .. ..... .. ass Oligohymenophorea ... . .... .... ......... . ichea olpodea and left oral ..... ..... .. .. .... ..... .. . relictea chea ophorea lass Colpodea ........ ... 31 .. ... .. ... ....... ... ..... 37 .. ... . . ass Spirotrichea phorea 80 opylea tea (Fig . 81) Class Heterotrichea . . . . . . oo . . . . . . . . . . . 32' . Fibril connection otherwise ............ 33 00 23 . Fibril orig inates from right of kinetosomes of kinetid and is directed anterior and to right of kinety (Fig . 82) .... .. .......... .... .. ... ..... ..... ... ..... Class Oligohymenophorea .. ...... (F ig. 83) Subclass Scuticociliatia 33 '. Fibril originates from left of kinetosomes of kinetid and is directed posteriad and left ........ .... .... (Figs. 84-86) Class Colpodea 34 . Oral area extends out over body surface as a series of oral polykinetids .. .... .. . .. .. .............. .. ...... ... (Fig. 87) Class Colpodea .. .. .... 00(Fig . 98) Class Nassophorea .... .. .... . 34'. Oral area confined to area adjacent to the cytostome ; frequently with some kind of incavitation .............. .. ........ .. ..... ........ ........... 35 35 . With a zig-zag configuration of kineto-somes to the right of the cytostomal area; oral polykinetids to the left and/or anterior but not extending anteriorly over the body surface (e .g. genus Miamiensis; Fig . 88) ........ .... .. .. 36 35' . Without such a zig-zag configuration ; at least one oral polykinetid located on either side of the cytostome ........... .. .... .... ... ... ....... ... .. .... .... . . .......... (Figs. 89 ,90) Class Colpodea .. .... 00 .. 36 . With two or more kinetosomes in pairs , rows , or clusters that are postoral (e.g ., the C segment of the oral dikinetid) ...... .. .. .... .... .. .. .. .. .. .. .. .. 00 Class Spirotrichea .. .. .. .. .. .......... .. . .. 00 (Fig. 91) Subclass Protocruziidia ...... .... . ....... Class Oligohymenophorea 00 ........... .. 00 .. (Fig . 92) Subclass Scuticociliatia .. .. 36'. Without such a postoral row or cluster of kinetosomes .... .. .. .. .. .... .... .. .. . .Class Colpodea .. .. .. .. .. .. (Fig . 93) Order Cyrtolophosidida 37. Somatic kinetids accompanied by an obvious fiber frequently as wide or wider than the kinetosomes of the kinetid and visible only by focusing through to the proximal ends of the kinetosomes (Figs . 94-97) ............ .. .......... .. .... .. Class Phyllopharyngea ...... ...... .. .. 00 .. .... . 37' . Without such an obvious fiber ...... 38 00 38. Oral ciliature extends out over body surface .. ................................. ............. . .... .... 39 CILIOPHORA, KEYS 403 38' . Oral ciliature confined to region surrounding ........ the cytostome .. .. .. .................... .......... ....... .... 40 39. With a cytopharyngeal basket or cyrtos ; with usually inconspicuous adoral and postoral polykinetids .. .... .. ...... ..... .... .... .... .... ... .... ... ..... .. .. .. .. (Figs . 98,99) Class Nassophorea 00 ...... . ·; . . . . \' .. . ... . .. . . 0 .. ·. .0 93 .......... 39'. With cyrtos; with paroral and preoral dikinetid files; somatic ciliation confined to ventral (=oral) surface . (Figs. 100,101) ..... . . . ... . .. . . . . . . . . . . . . . . ... . . .. . . Cl 40 . With a cyrtos ...... ....... ... ........ ... .... ..... ... 40' . Without a cyrtos .......... ........ ...... . .. ........ . 41 . With at least three polykinetids left of cytostome ; numerous somatic medium to large organisms ........ ....... .... .......... . . . . .. . . . .. (Figs . 102 ,103) Class Nassophorea 41'. With two to several polykinetids left of cytostome ; few somatic kineties; usually small organisms .. ...... ... ... ...... ... ... ........ .. .. .. . . . . . . . . . . (Figs. 104,1 05) Class Nassophorea 42 . With loosely organized nematodesmata in oral and perioral region .... ......... ......... ............... 42' . Nematodesmata not obvious or absent ..... .. ...... ..... ....... ... ........ .. ............ . 43 . Oral kinetids on left side in short single rows of kinetosomes and not obviously organized as polykinetids .. (Fig . 106) ... ... .... ... ... .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43'. One to six oral polykinetids on left side ....... ... ... ..... ... ........ .... .. ... . Class Nasso ..... ..... (Figs. 107,108) Subclass Peniculia 44 . Oral structures at the base of a ciliated preoral depression , often making them difficult to see ......... .... .. . Class Nassophorea ............ .. ..... (Fig. 113) Subclass Peniculia .... ... ................... Class Oligohymenophorea .. . ... .. (Fig. 109) Suborder Ophryoglenina 44' . Oral apparatus in a shallow oral cavity; three oral polykinetids anterior or anterior-left of the cytostome ..... ........ ... ........ ..... ........ ... ...... ........ .. ... ...... Class Oligohymenophorea (Fig . 112) .. .... Subclass Hymenostomatia (Fig. 11 0) ... ..... Subclass Scuticociliatia 44" . Small rosette-like aperture cytostome ; two to three postoral kinetal fragments called the x,y,z kineties , usually present in tomite ; typically symbionts of crustacea ......... .Class Oligohymenophorea (Figs . 111, 114) ... .. Subclass Apostomatia CILIOPHORA, KEYS ~~~) ass Phyllopharyngea ·: :)~-:~ .. .... . 41 :.; ;;_::~::; .. ... 42 kineties ; .... ... . . 43 .. ... ....... ...... 44 ..... .... . . . . . . . . . . Class Nassophorea .. above 1. Ciliates green .. .. .... .... .. ...... .................. .... .. ...... 2 1'. Color otherwise .................. .. ................ 2. Green color confined to specific vesicles or vacuoles (likely due to endosymbiotic unicellular algae or sequestered chloroplasts) o o o o o o o o o o oo o o o o o o o o o o o o o o o o o o o o o o o o o o oo 2'. Green color diffuse ...... .... ................ .......... ...... 5 3. Colored grass-green , due probably to presence of green zoochlorellae or sequestered chloroplasts . Some common genera are as follows: C/imacostomum, Euplotes, Holophrya, Co/eps, Prorodon, Urotricha, Paramecium, Frontonia , Spirostomum, Vorticella , Stentor, Strombidium, Laboea, Tontonia 3'. Vesicles not grass-green ........ .. ............ 4 4. Vesicles greenish-brown (possibly due to a cryptophyte endosymbiont) ; marine ciliates ..... ... ... .... .... ... .. ... Cyclotrichium, Mesodinium 4' . Vesicles otherwise , possibly due to undescribed endosymbiont from some other protistan group (e .g., dinoflagellate) or due to sequestered chloroplasts .. .... Strombidium, Laboea, Tontonia 5. Grass-green color diffuse , possibly due to ingestion and incomp lete digestion of food ; found in many algivorous ciliates . • • .. • • • • .. • Nassula, Chilodonella, .. • • • • • • • 000000 00 0000 00 ...... .............. Trithigmostoma, Frontonia 00 .... .... 5' . Green color not grass-green ; in small vesicles ..... .. ..... . .. . Stentor and other stentorids 6. Red colored .. ...... ............ .. .. .. .................... ..... .. . 7 6' . Color otherwise .... ........ .. ...... .. ........ .. ...... .. .... 10 7. Pigment in vesicles or vacuoles .................... . 8 7'. Pigment diffuse; oral serial polykinetids .......... ...... .. .... ............ ........... .. ... .. .... .... .. ...... ... 9 8. Locomotion by bundled cilia as cirri ........ Stichotrichs, such as Holosticha and Keronopsis CILIOPHORA, KEYS 405 00 .. 00 .. 00 0 6 oo ooo oo o o oo oo o o oo o ooo ooooooooooo 00 .... 00. 00 oooo · 8' . Cirri not present; red pigments confined to food vacuoles enclosing incompletely digested blue green algae . Nassu/a , Pseudomicrothorax 8" . Vesicl es brownish-red ; marine .... .. .. ...... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. Cyclo 9. Trumpet-shaped ; body contractile .. .. .... .. .. .. .. ...... .. ....... ........ ........ . . . . 9' . Not trumpet-shaped ; body not contractile .......... .... ...... .. .... .. .... .... .. .. 10. Golden yellow .. .. Some species of ........ . Nas 10'. Color otherwise .................... .. ...... .. 11 . Blue to purple with prominent adoral polykinetids .................. .. .... .. .. Som 11 '. Ciliates appear black ....... .................. 12. Black in the light of the compound microscope; color due pigment .. ........ ... ..... .......... ..... .. 12 '. Lack of light transmission due to densely packed food vacuoles ; often occurs in well-fed histophagous ciliates ................ Tetrahymen ... .. Ph i/aster, Ophryoglena, lchthyophthirius 1. Attached to substrate ...... .. .. .. .. .. .. ... 1' . Not attached , free swimming , crawling .... .. . 2. Dendritic forms without a stalk -suctorians such as (Fig . 1) Dendrosoma(Fig. 2) .. ......... . . .. . .. . .. . .. . .. . .. . .. . .. . .. . . 2'. Arborescent forms stratum .......................................... 2". Forms with rigid tentacles ; mostly sessile organisms attached to substrates or other organisms ; common or generalized form of many suctorians ; Oendrocometes, attached to fresh -water amphipods (Fig . 16) .. .. .. .. .. . Heliophrya , attached to substratum (Fig. 1 7) , Ephelota , attached to substratum and other organ isms ; marine or brackish water (Fig . 1 8) 2"'. Forms with hyaline lorica .... ... ..... ...... . CILIOPHORA, KEYS .... .. .. .. trichium, Mesodinium .... .. .. . . . . . .... Some stentorids ... ... ... Blepharismidae sula .. .. .... .. .. 11 e stentorids ... .. ... 12 to a true . .. . Stentor niger a , .. .. .... .... .... .. 2 ... 6 .. . . .. . . .. . .. . .. . .. . .. . ... Trichophrya attached to sub- . .. ..... .. .. .. ... 3 . .. .. .. ... .. .... 5 2"" . Attached trumpet- or bell-shaped forms ; larg e form s like Stentor (Fig. 20) or small fo rms like some peritrichs Attached flower-like or vase -shaped forms , such as chonotrichs attached to invertebrates .. .... .... .... ..... ...... ..... ... ..... ....... 3. Attached by stalk ..... .. ....... ... ... .... ........ 3 '. Arb oroid lorica attached directly to sub- stratum , not stalked .. ...... (Fig. 4) Marynids, ........ ..... ... ..... ........ (Fig . 5) some sticho 4. Non-contractile stalk .. ..... .... .. ... .... ....... . . . . . . . . . . . . . . . . . . . . . . . . . . Per 4'. Cont ractile stalk .. .... ... . .... . (Fig. 3) Vortic 5. With hyaline lorica attached to sub-stratum without a stalk.. ..... .. .... ..... ... ... .. .... Ch ilodone llids , some peritric hs , and (Fig . 7)heterotrichs 5' . Fo rms with hyaline lo substrat um by a stalk or stalk-like process ... (Figs. 8-1 0) Some peritrichs and suctoria 6. Forms that are long, slender in shape , often flat and ribbon-like ; mostly brackish or marine , such as (Figs . 24 kary orelicteans, (Fig . 27) non-contractile karyorelicteans,.. .. .. .... ... ... .. ...... ....... . . . . . . . . . . . . . . . . . . . . . . (Figs . 28- 6' . Forms that are long , slender in shape, but roun d in cross-section .... .. .... ..... e.g. (Fig . some heterotrichs , (Fig . 32) karyore lict ea ns . CILIOPHORA, KEYS 407 (Fig . 21). .. .. ....... .. (Fig. 22) .. .. .... .. 4 trichs ..... ....... . itrichs such as epistylids ellid (Fig . 6 ) rica attached to -26) contrac tile 24 25 .. ... ......... .. . 31 30) some haptorians 3 1 ) some 408 CILIOPHORA, KARYORELICTEA SUBPHYLUM POSTCILIODESMATOPHORA 1'. O Gerassimova and Seravin , 1976 2. So Ciliates with somatic dikinetids that have b postciliodesmata , a special arrangement of 2'. S overlapping postciliary microtubular ribbons. . They lack parasomal sacs. Oral dikinetids , when present , have their postciliary microtubular ribbons often extending to support the cytopharynx. Oral polykinetids , when present , vary (from two to three rows of kinetosomes , usually with a complex T infraciliature . Polykinet ids of heterotrichs may and m spiral out of the oral cavity onto the body surface naked where they define the peristomal field. The inter extrusomes are mucocysts, rhabdocysts , and/or pigmentocysts . The cortical alveolar system is poorly developed. The oral apparatus of the prot e r usually undergoes regression and redevelopment prior to and/or during cytokinesis. Two classes . 1. b s 9<9 1'. I c 1. Non-dividing , paradiploid macronuclei ; oral polykinetids absent ...... Class Karyorelictea 1' Polyploid macronuclei dividing by involvement of extramacronuclear microtubules ; left serial N oral polykinetids typically conspicuous ..... ...... .. . naked .............. .. ...... .. ............... Class Heterotrichea circu gener CLASS KARYORELICTEA Corliss , 1974 Long , vermiform , flattened ; many genera have one barren surface ; extremely contractile, except Loxodida ; two to many macronuclei contain approximately (sometimes slightly more than) the diploid amount of DNA; macronuclei form by 1. division of micronuclei , then differentiate; the v micronuclei divide , apparently by eumitosis ; three . orders . 1'. W s KEYS TO THE ORDERS OF THE CLASS c b 9<9 2. 1. Oral cilia inconspicuous, or none ....... ..... ... .. ...... . 2' . ... .. ..... .... ........ ... .. ... ... .. Order Protostomatida ral structures not as above .. .... ... .. .... .... ......... 2 matic cilia many, on right surface of flattened ody .. ...... .... ... ........ ... ........... .... Order Loxodida omatic cilia over entire , vermiform body ....... . ............ .... .. .. ..... Order Protoheterotrichida
Type species
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*Newly elevated or recognized taxa compared to Small and Lynn (1981 , 1985) . , KEYS 395 KEYS TO TAXA The introductory keys that follow are designed to allow the user to place an unknown ciliate within a certain group, usually at the level of class or subclass. This will then lead to keys that w iII permit identification to genus within one of the many families of ciliates. The characteristics utilized in the keys are not necessarily the major criteria upon which the various systematic categories have been founded. While body shape, arrangement of, and/or presence or absence of cilia, and presence or absence of a cytostome have been used as key characteristics , frequently ultrastructural features of the kinetid or the ultrastructure of the cytostomal area coupled with various basic morphogenetic attributes are the most important systematic criteria for actually grouping ciliates into their proper taxa (Small and Lynn, 1981) . If one were to devise a completely "natural" set of keys, these keys would require the use of ultrastructural features . The first key, Key to the Ciliates, should permit one to place the unknown ciliate into a particular group, ranging from genus to class. Following this key is a key relying on the color of the ciliate , Key to Some Common, Colored Ciliates, if color seems a particularly striking feature. Finally, if the shape seems especially different, the user might try the Key to Common Ciliates by Shapes. These keys should take the reader to the subsections within the Keys to the Classes , where there are further keys allowing identification to genus. We have restricted our treatment to selected genera, most having been redescribed or described using silver-staining techniques. Thus , not all described genera are included in these keys. Other keys and guides to genera of freshwater ciliates are provided by Curds (1982) , Curds et al. (1983), Foissner et al. (1991, 1992, 1994, 1995) , and Patterson ( 1 992). Many genera have not been redescribed since Kahl (1930-1935), whose monograph should be consulted for the descriptions of many species. Species descriptions can also be found by refer ring to the sources of the many illustrations in this chapter. The user must be forewarned that the illustrations used are given as examples of genera only ; that is, the figures illustrate one or several species considered typical of the genus but do not represent the array of species found in some genera. The user should not attempt to identify a species using these keys ; rather, reference should be made to the primary literature or to Kahl (1930-1935). The sizes of the included taxa are meant only as a guide ; size itself can be a very variable characteristic , both among and within species. NOTE. All scale-bars have their smallest division as 25 IJm . bLM 1. With one or more (mostly more) feeding tentacles and without a true cytostome or cytopharynx ... ... .... ClassPhyllopharyngea ... .... ..... . ... .... . (Figs .1,2) Subclass Suctoria .. ... ........ ................ ... ... .. Class Litostomat ... .... .. (Fig. 3) Family Actinobolinidae 1'. Without tentacles .. .. .... .... .......... .. ... ......... 2. Apparently without a cytostome and without a cytopharynx ; may be attached or unattached ; sometimes endosymbiotic ..... .... ... .. ..... .. ......... 2' . With a cytopharynx and/or cytostome .... ... .. .. 6 3. Free-living forms ...... .......... ......... .. . ... ..... . 3' . Not free-living forms ; endosymbionts ........... 5 4. Flattened , ribbon-like forms ; psammo- bionts , with attached rod-shaped bacteria on the non-ciliated surface ; brackish or marine .. . .... .. .. .......... ... ..... .. ..... Class Karyorel .. . ........ .. (Figs . 4,5) Order Protostomatida 4' . Flattened, ribbon-like forms with rows of toxicysts inserted along one margin of the ora I area (actually, there is a slit-shaped cytostome adjacent to the toxi .... ... .............. ..... .... ..... .. . Class Litostom ..... .. ... . (Figs . 6,7) Order Pleurostomatida 5. Small , pyriform ciliates with mostly bipolar kineties; with one surface devoid of an oral architecture; found in the hemocoel of PHORA, KEYS arthropods or free-living ............. ....... Class Oligohymenophorea (Fig . 8) .... ....... ... ... . .... .. .......... .... .. Family Curimostomatidae) ea ........ 2 . 3 . ... 4 ictea cysts) atea C 5' . Variously shaped (but frequently cylindrical) ciliates with many kineties ; often found in the lumen of digestive tracts of many annelids and some molluscs .. Class Oligohymenophorea ............... (Figs. 9,10) Subclass Astomatia 6. Sessile ciliates, i. e., attached to a substrate by an extra-cellular product or cellular process , such as a lorica and/or contractile or non- contractile stalk or stalk-like process .. . ..... 7 6' . Free-swimming, non-sessile , sedentary ciliates attached within lorica; mostly planktonic ..... ......... ..... ... ..... .... .. ....... ... .. ..... .. 14 6" . Free-swimming, non-sessile , non- sedentary ciliates ... .... ..... ... ... ....... .. ... ..... ... ... 18 7. Loricate ciliates (non-planktonic, except those attached to planktonic invertebrate hosts) .... ........ .... .... .. ......... .. ... .. .. ... .. .... .. ... ... 7'. Ciliates lacking a lorica but with a secreted hold-fast structure , which may partially envelop the body ... .... .......... .... ...... .. ...... ... .. .. 15 8. Loricate organisms with cilia; lorica may or may not bear a stalk, or the lorica itself may bear a stalk-like extension for attachment to sub-strate ... ....... ... .. ... .... .. ... .. ... ... ....... ..... ..... . 8' . Loricate ciliates without cilia (except during division or other morphogenetic events) ; with suctorial tentacles (see 1') ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Class Phyllopharyn ..... .. .. ...... (Figs . 11 , 12) Subclass Suctoria 9. Ciliates free to move within lorica ; somatic cell surface with cilia ; specialized oral c iIi a ·············· ······· ···· ········· ···· ... ..... .. ...... .. ... ... .. . 9' . Ciliates not free to move within lorica but attached to lorica .. ... .... Class Spirotrichea .. ............... (Figs. 13,14) Order Tintinnida 10. Oral ciliature at the anterior apex, or the cytostome appears to be anterior apical ...... ....... .... ... ...... .... ... ..... ...... ..... ... ........ 10' . Oral region clearly removed from this anterior position .. .. ...... ... ... ........ .... ..... .. .. .. ... 12 11. Oral ciliature at anterior end of cell without in-pocketing of the cell surface surrounding the cytostome .... ....... ...... Class Prostomatea .. ... .. ....... .... (Fig . 15) Family Metacystidae ... ......... ..... .............. ... ...... ....... Class Colpodea ... .. .. . (Fig . 16) Family Cyrtolophosididae ILIOPHORA, KEYS 397 11'. Cytostome at base of vestibulum ; lorica frequently arborescent. ....... .Class Colpodea .... .. ..... .......... (Fig. 17) Family Marynidae 12. Cytostome of loricate ciliate situated in a shallow ventral oral cavity .. .... ......... .... 13 .... 8 148 ! . 9 ! .... .... ....... . gea .... 10 and 398 CILIOPHORA, KEYS 12'. Cytostome of loricate c oral cavity ; ciliate's during observation so t free-swimming ; ciliate shaped with many rows o large set of oral polyk non-attached end and le 18 cavity proper .... ... .. .. ... . ....... ... ' -.. 12" . Attachment of ciliate . b1 •• - t:. surface of the body; wi 19 -::::= -=?"" . ciliated; prominent seri leading to cytostome at ... .. .... .......... .... .... (Figs . 19,20 13. Cytostome at base of sha few oral polykinetids an parts ..... ..... ...... .... .. . (Fig . 16) F 13'. With oral polykinetids paroral ciliature ... .. ... ... ... ... ... . . .. (Fig. 21) Family Caly 13". Cytostome with shallow spiralling serial oral p ..... .... .. .... . .. ...... ..... .. ...... ( 14. Attachment of cilia process (nonkinetosoma site frequently on the . . . . . . . . . . . ..... .. .... .... .. 14'. Attachment of th at the base of the lor accompanied by a stalk ciliate with cytostome infundibulum ; with pr ciliation that include polykinetid and the h a trophont , devoid of . . . . . . . . . . . (Figs. 25 ,26) Su 15. Hold-fast structure around the base of att flattened aboral proce iliate situated in deep, attachment easily altered hat it may become s may be trumpet- f somatic cilia and a inetids coursing over ading into the oral ... .... Class Heterotrichea ... (Fig. 18) Family Stentoridae appears to be a broad th somatic surfaces al oral polykinetids base of deep oral funnel ... .. .... . ... .... Class Heterotrichea ) Family Folliculinidae llow oral cavity with d paroral of two . ... .. ....... ...... ... Class Colpodea amily Cyrtolophosididae and large velar .. ....... ... .. ... .... ... .. ... ... .. .. . .. . . . . . . . . . . Class Oligohymenophorea ptotrichidae oral cavity and olykinetids ... ... .... .. .. .. .. . .. . . . .. . . .. . . . . . . . .. Class Spirotrichea te to lorica by peduncular l) with attachment side of the lorica .. . . . . . . . . . . . . . . . . . . . . . . . . . .. Class Spirotrichea (Figs . 23 ,24) Order Tintinnida e ciliate to the lorica is ica; may/may not be or stalk-like process ; at the base of deep ominent peristomal s one continuous oral aplokinety or paroral ; as somatic ciliation ........ . . . . . . . . . . . . . . Class Oligohymenophorea bclass Peritrichia is secreted as a ring achment or appears as ss .... ........ ...... ..... ... .... 16 15' . Hold-fast structure is a secreted stalk or stalk-like process that partially envelops the body ...... .... ..... ........ .... ............ 16. Without any ci lia (except during division or other morphogenetic events); with conical- shaped suctorial tentacles arranged in bundles around periphery of the non-attached portion of the body ; non-contractile (see 1) ... ....... . ........ .......... ......... . .Class Phyllopharyn ..... ....... .. (Figs . 27 ,28) Subclass Suctoria 16'. With obvious peristomal cilia present (see 14') ; body contractile ; ectosymbiotic usually .. ...... .... .... .... ... .. Class Oligohymenoph ... .... .. . (Figs . 29 ,30) Subclass Peritrichia 17. With sparse somatic ciliation restricted to surface bearing the oral area ; body non- contractile ; usually ectosymbionts of cru stacea . .. . ... ..... Class Phyllopharyngea (F igs. 31 ,32)Subclass Chonotrichia 17'. With obvious peristomal ciliature (see 1 4') ; body contractile ................ ...... ....... .. ................ ... ...... Class Oligohymenophorea .. . .. .... (Figs . 33 ,34) Subclass Peritrichia 18. With oral cil iature , cytost cytopharynx positioned on or near the anterior or posterior apex ; may or may not have anterior cytoplasmic projection ..... .... 19 18' . Oral structures not positioned near an apex , but rather ventral. .. .............. ... ... ... 19. Oral structures at or on the surface; if in doubt, the cavity-like area preceding the cytostome does not kinetids .. ... ...... ... ..... ... ....... ... . 19' . With an oral cavity or vestibulum whose walls bear specialized , often densely packed , kinetid files ; cytostome at its base ; may be endosymb iotic ... . . . . . . . . . . . . . . . (Figs . 35 ,36) Class .. .... ... .. .. .. ....... ...... SubclassTricho ... ... ... .... .. .. .... ... ... ..... . .. . . ... ... .. ...... ..... (Fig . 37) Family Sonderi 20 . Oral area at anterior end ; living in sandy or sil ty brackish or marine benthos ; tube -I ike or ribbon-like body ; somatic cilia variable ; oral ciliature inconspicuous or absent ........ ... ... ..... ..... . .Class Karyor ....... ....(Fig . 38) Family Trachelocercidae CILIOPHORA, KEYS 399 ........ ..... .. .. ... ... 17 gea orea ... ........ . ome , or ... ...... .... 21 bear cilia or ... .. .............. ... 20 .... ... ........... .... ..... ... .... .. . Litostomatea stomatia ... Class Plagiopylea idae tion elictea 400 CILIOPHORA, KEYS 20 '. Cytostome (or cytostomal-cyto-pharyngeal structures) at the anterior pole ; coronal ciliature ; clavate cilia located within kineties ; somatic ciliation variable , may be as rings or bands ; toxicysts within the borders of the coronal ciliature ..... .. .. .. Class Litostomatea ... .... .... .. (Figs. 39 , 40) Subclass Haptoria 20 ". Cytostome (or cytostomal-cytopharyngeal structures) at the anterior pole ; without clavate cilia ; most kineties bipolar ; without brosse or toxicysts ; may be endosymb iotic ... .. . ... ..... .. ................. .... .... ... .Class Prostomatea .......... .... .. .. .. (Fig . 41 ) Order Prostomatida ................. ... ..... ........... .Class Litostomatea ... .... .. (Fig . 42) Suborder Archistomatina 20"' . Coronal ciliature and cytostome near the ventral anterior ; brosse poly-kinetids may interrupt the coronal ciliature as they extend from anterior pole posteriad ; toxicysts near brosse , and always external to coronal ciliature sensu stricto ; somatic kineties terminating near brosse , often forming suture line ... ........... ... ... ...... ....... Class Prostomatea .... .... .... (Figs . 43,44) Order Prorodontida 21 . With slit-like area for ingestion (but no permanent cytostome) placed along one edge of flattened ribbon-like body and extending up to 1/2 body length ; anterior end frequently curved ; toxicysts inserted along one edge; external to toxicysts , dikinetids at bases of coronal ciliature ; frequently large species as predators of peri trichs ..Ciass Litostomatea ........ .. ... .. (Figs . 45 ,46) Subclass Haptoria 21' . Cytostome not slit-like ; pericytostomal region removed from anterior and accompanied by specialized oral ciliature 22 . Specialized oral ciliature confined to region adjacent to the cytostome (e .g. Tetrahymena ; I 47 22 '. Specialized oral ciliature not so confined but extending out over the body surface (e .g ., Nassula, Stentor, peritrichs; Figs . 4 8-5 0) 23 . Oral depression , a densely ciliated cavity w ith no distinct oral polykinetids ; either ventral or ventra-posterior in position ; may be endosymbiotic ..... ......... ... .. .... .. ..... .... ... ... .... .... ... ... ... .. ........... .. .. . (Fig . 51) Class Plagiopylea ...... .... .. .... .. ......... ........... Class Litostomatea .. .... .. . (Fig. 52 , 53) Order Vestibuliferida 23' . Oral ciliature not as above ; with ventral or ventra -posterior oral areas .... .......... ...... .. 24 24. With conspicuous oral ciliature that some- times becomes apparent only when the ciliate stops movement. ..... ..... .......... ..... .... .... .. ..... 25 24'. With inconspicuous oral ciliature .. .... .. .... 30 25. Oral ciliature becomes obvious when ciliate ceases movement; velar ciliature of paroral dikinetids is then extended ...... .... .... ... .... ..... .. ... . ..... .... .. .. .. . ....... .. Class Oligohymenophorea ... .... (Figs . 54 ,55)0rder Pleuronematida 25'. Conspicuous ciliature otherwise .... ... ...... 26 26. Oral cavity embellished by conspicuous cilia (or infraciliature) on left and right sides ; with right oral dikinetids; without serial oral polykinetids ... ............. ...... ........ .............. ..... 27 26' . With conspicuous polykinetids forming a serial left oral polykinetid zone, frequently extending anteriad to circumscribe a peristomal field (e.g. Class Colpodea; Class Spirotrichea; Class Heterotrichea; Figs . 56- 58} ....... ... ......... .. .... .... ... ... ... .. .. .. .... .... ... ... .... 29 26" .With obvious peristomal cilia restricted to adoral band bordering the peristome (see 14') ; may be ecto- or endosymbiotic ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . Class Oligohymenophorea .. .. ... . (Figs . 59, 60) Subclass Peritrichia 27 . Frequently with a large vacuolar space underlying these oral cilia ........ .... ........ . .. . .. . . . . . . . . . . . . . .. .. . .. Class Oligohymenophorea ...... .. (Fig. 61) Subclass Hymenostomatia 27' . Without underlying vacuolar space .. . ..... .. . 28 28 . Oral area comprises more than 2/3 ventral surface ........ ... ..... ... .. ..... . Class Nassophorea ............ ... .(Fig. 62) Family Lembadionidae CILIOPHORA, KEYS .. : : : .. ·· · .·.·. .··>:·>- 28'. Oral area comprises less than 1/2 ventral surface ..(Fig. . . . . . . . . . . . . . . . . . . . . . . . . Cl 29 . With conspicuous left and/or preoral serial oral polykinetids ... .. .... .... .... ... .... . . . . . . . . . . . (Figs. 64-67) Class Spirotr ..... ....... .. ...... .. (Figs. 56 ,68) Class C 29' . With conspicuous right ciliature ........ ..... ......... .. ..... ..... . . . . . . . . . .. (Figs . 69 , 70) Class Karyo .. ...... . ..... ..... (Fig. 71) Class Heterotri .... .. ...... ..... .. .. ..... Class Oligohymen ..... .... .. (Fig. 72) Subclass Scuticociliatia ........ .. .... ... ... ... .... ... (Fig. 73) C NOTE: The majority of genera keyed belowthis point will have inconspicuous mouthparts. Certain identification of these genera and proper use of this key will require that the specimens be stained by the silver-proteinate or protargol silver-staining procedure . b 9<9 30 . Somatic kinetids of most somatic kineties with paired kinetosomes , with or without cilia on both kineto-somes ....... .... ......... .... 30' . Somatic kinetids of most somatic kineties with single kinetosomes , with or without cilia ... ... .. ........... ...... ..... ....... 30" . Somatic polykinetids , either in linear or polygonal arrays( Figs . 74 ,75,77) ....... ... ..... .. ..... .. .... .. ... ....... ... ... Cl .. ..... .... .... ..... (Figs . 76) Class Nasso ..... ..... .. ... ....... (Fig. 78) Class Plagi 31. Somatic kinetids with paired kineto-somes accompanied by an obvious fiber such as basal microtubules , postciliary microtubular fiber, kinetosdesma, or transverse microtubular fiber ; fiber may be as wide in cross-section as the paired kinetosomes ... . 32 31'. Such a fiber absent or not conspicuous ... ... 34 32. Kinetosome pair oriented obliquely to the fiber ; the fibril from each pair arises at the posterior kinetosome and extends posteriad to insert in the postciliary microtubular fiber (Figs. 79 ,80) ... ...... ... .Class Karyorelic CILIOPHORA, KEYS 63) .... .... ... .... .. .. .... ... .. ..... .. ass Oligohymenophorea ... . .... .... ......... . ichea olpodea and left oral ..... ..... .. .. .... ..... .. . relictea chea ophorea lass Colpodea ........ ... 31 .. ... .. ... ....... ... ..... 37 .. ... . . ass Spirotrichea phorea 80 opylea tea (Fig . 81) Class Heterotrichea . . . . . . oo . . . . . . . . . . . 32' . Fibril connection otherwise ............ 33 00 23 . Fibril orig inates from right of kinetosomes of kinetid and is directed anterior and to right of kinety (Fig . 82) .... .. .......... .... .. ... ..... ..... ... ..... Class Oligohymenophorea .. ...... (F ig. 83) Subclass Scuticociliatia 33 '. Fibril originates from left of kinetosomes of kinetid and is directed posteriad and left ........ .... .... (Figs. 84-86) Class Colpodea 34 . Oral area extends out over body surface as a series of oral polykinetids .. .... .. . .. .. .............. .. ...... ... (Fig. 87) Class Colpodea .. .. .... 00(Fig . 98) Class Nassophorea .... .. .... . 34'. Oral area confined to area adjacent to the cytostome ; frequently with some kind of incavitation .............. .. ........ .. ..... ........ ........... 35 35 . With a zig-zag configuration of kineto-somes to the right of the cytostomal area; oral polykinetids to the left and/or anterior but not extending anteriorly over the body surface (e .g. genus Miamiensis; Fig . 88) ........ .... .. .. 36 35' . Without such a zig-zag configuration ; at least one oral polykinetid located on either side of the cytostome ........... .. .... .... ... ... ....... ... .. .... .... . . .......... (Figs. 89 ,90) Class Colpodea .. .... 00 .. 36 . With two or more kinetosomes in pairs , rows , or clusters that are postoral (e.g ., the C segment of the oral dikinetid) ...... .. .. .... .... .. .. .. .. .. .. .. .. 00 Class Spirotrichea .. .. .. .. .. .......... .. . .. 00 (Fig. 91) Subclass Protocruziidia ...... .... . ....... Class Oligohymenophorea 00 ........... .. 00 .. (Fig . 92) Subclass Scuticociliatia .. .. 36'. Without such a postoral row or cluster of kinetosomes .... .. .. .. .. .... .... .. .. . .Class Colpodea .. .. .. .. .. .. (Fig . 93) Order Cyrtolophosidida 37. Somatic kinetids accompanied by an obvious fiber frequently as wide or wider than the kinetosomes of the kinetid and visible only by focusing through to the proximal ends of the kinetosomes (Figs . 94-97) ............ .. .......... .. .... .. Class Phyllopharyngea ...... ...... .. .. 00 .. .... . 37' . Without such an obvious fiber ...... 38 00 38. Oral ciliature extends out over body surface .. ................................. ............. . .... .... 39 CILIOPHORA, KEYS 403 38' . Oral ciliature confined to region surrounding ........ the cytostome .. .. .. .................... .......... ....... .... 40 39. With a cytopharyngeal basket or cyrtos ; with usually inconspicuous adoral and postoral polykinetids .. .... .. ...... ..... .... .... .... .... ... .... ... ..... .. .. .. .. (Figs . 98,99) Class Nassophorea 00 ...... . ·; . . . . \' .. . ... . .. . . 0 .. ·. .0 93 .......... 39'. With cyrtos; with paroral and preoral dikinetid files; somatic ciliation confined to ventral (=oral) surface . (Figs. 100,101) ..... . . . ... . .. . . . . . . . . . . . . . . ... . . .. . . Cl 40 . With a cyrtos ...... ....... ... ........ ... .... ..... ... 40' . Without a cyrtos .......... ........ ...... . .. ........ . 41 . With at least three polykinetids left of cytostome ; numerous somatic medium to large organisms ........ ....... .... .......... . . . . .. . . . .. (Figs . 102 ,103) Class Nassophorea 41'. With two to several polykinetids left of cytostome ; few somatic kineties; usually small organisms .. ...... ... ... ...... ... ... ........ .. .. .. . . . . . . . . . . (Figs. 104,1 05) Class Nassophorea 42 . With loosely organized nematodesmata in oral and perioral region .... ......... ......... ............... 42' . Nematodesmata not obvious or absent ..... .. ...... ..... ....... ... ........ .. ............ . 43 . Oral kinetids on left side in short single rows of kinetosomes and not obviously organized as polykinetids .. (Fig . 106) ... ... .... ... ... .. ... .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43'. One to six oral polykinetids on left side ....... ... ... ..... ... ........ .... .. ... . Class Nasso ..... ..... (Figs. 107,108) Subclass Peniculia 44 . Oral structures at the base of a ciliated preoral depression , often making them difficult to see ......... .... .. . Class Nassophorea ............ .. ..... (Fig. 113) Subclass Peniculia .... ... ................... Class Oligohymenophorea .. . ... .. (Fig. 109) Suborder Ophryoglenina 44' . Oral apparatus in a shallow oral cavity; three oral polykinetids anterior or anterior-left of the cytostome ..... ........ ... ........ ..... ........ ... ...... ........ .. ... ...... Class Oligohymenophorea (Fig . 112) .. .... Subclass Hymenostomatia (Fig. 11 0) ... ..... Subclass Scuticociliatia 44" . Small rosette-like aperture cytostome ; two to three postoral kinetal fragments called the x,y,z kineties , usually present in tomite ; typically symbionts of crustacea ......... .Class Oligohymenophorea (Figs . 111, 114) ... .. Subclass Apostomatia CILIOPHORA, KEYS ~~~) ass Phyllopharyngea ·: :)~-:~ .. .... . 41 :.; ;;_::~::; .. ... 42 kineties ; .... ... . . 43 .. ... ....... ...... 44 ..... .... . . . . . . . . . . Class Nassophorea .. above 1. Ciliates green .. .. .... .... .. ...... .................. .... .. ...... 2 1'. Color otherwise .................. .. ................ 2. Green color confined to specific vesicles or vacuoles (likely due to endosymbiotic unicellular algae or sequestered chloroplasts) o o o o o o o o o o oo o o o o o o o o o o o o o o o o o o o o o o o o o o oo 2'. Green color diffuse ...... .... ................ .......... ...... 5 3. Colored grass-green , due probably to presence of green zoochlorellae or sequestered chloroplasts . Some common genera are as follows: C/imacostomum, Euplotes, Holophrya, Co/eps, Prorodon, Urotricha, Paramecium, Frontonia , Spirostomum, Vorticella , Stentor, Strombidium, Laboea, Tontonia 3'. Vesicles not grass-green ........ .. ............ 4 4. Vesicles greenish-brown (possibly due to a cryptophyte endosymbiont) ; marine ciliates ..... ... ... .... .... ... .. ... Cyclotrichium, Mesodinium 4' . Vesicles otherwise , possibly due to undescribed endosymbiont from some other protistan group (e .g., dinoflagellate) or due to sequestered chloroplasts .. .... Strombidium, Laboea, Tontonia 5. Grass-green color diffuse , possibly due to ingestion and incomp lete digestion of food ; found in many algivorous ciliates . • • .. • • • • .. • Nassula, Chilodonella, .. • • • • • • • 000000 00 0000 00 ...... .............. Trithigmostoma, Frontonia 00 .... .... 5' . Green color not grass-green ; in small vesicles ..... .. ..... . .. . Stentor and other stentorids 6. Red colored .. ...... ............ .. .. .. .................... ..... .. . 7 6' . Color otherwise .... ........ .. ...... .. ........ .. ...... .. .... 10 7. Pigment in vesicles or vacuoles .................... . 8 7'. Pigment diffuse; oral serial polykinetids .......... ...... .. .... ............ ........... .. ... .. .... .... .. ...... ... 9 8. Locomotion by bundled cilia as cirri ........ Stichotrichs, such as Holosticha and Keronopsis CILIOPHORA, KEYS 405 00 .. 00 .. 00 0 6 oo ooo oo o o oo oo o o oo o ooo ooooooooooo 00 .... 00. 00 oooo · 8' . Cirri not present; red pigments confined to food vacuoles enclosing incompletely digested blue green algae . Nassu/a , Pseudomicrothorax 8" . Vesicl es brownish-red ; marine .... .. .. ...... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. Cyclo 9. Trumpet-shaped ; body contractile .. .. .... .. .. .. .. ...... .. ....... ........ ........ . . . . 9' . Not trumpet-shaped ; body not contractile .......... .... ...... .. .... .. .... .... .. .. 10. Golden yellow .. .. Some species of ........ . Nas 10'. Color otherwise .................... .. ...... .. 11 . Blue to purple with prominent adoral polykinetids .................. .. .... .. .. Som 11 '. Ciliates appear black ....... .................. 12. Black in the light of the compound microscope; color due pigment .. ........ ... ..... .......... ..... .. 12 '. Lack of light transmission due to densely packed food vacuoles ; often occurs in well-fed histophagous ciliates ................ Tetrahymen ... .. Ph i/aster, Ophryoglena, lchthyophthirius 1. Attached to substrate ...... .. .. .. .. .. .. ... 1' . Not attached , free swimming , crawling .... .. . 2. Dendritic forms without a stalk -suctorians such as (Fig . 1) Dendrosoma(Fig. 2) .. ......... . . .. . .. . .. . .. . .. . .. . .. . .. . .. . . 2'. Arborescent forms stratum .......................................... 2". Forms with rigid tentacles ; mostly sessile organisms attached to substrates or other organisms ; common or generalized form of many suctorians ; Oendrocometes, attached to fresh -water amphipods (Fig . 16) .. .. .. .. .. . Heliophrya , attached to substratum (Fig. 1 7) , Ephelota , attached to substratum and other organ isms ; marine or brackish water (Fig . 1 8) 2"'. Forms with hyaline lorica .... ... ..... ...... . CILIOPHORA, KEYS .... .. .. .. trichium, Mesodinium .... .. .. . . . . . .... Some stentorids ... ... ... Blepharismidae sula .. .. .... .. .. 11 e stentorids ... .. ... 12 to a true . .. . Stentor niger a , .. .. .... .... .... .. 2 ... 6 .. . . .. . . .. . .. . .. . .. . .. . ... Trichophrya attached to sub- . .. ..... .. .. .. ... 3 . .. .. .. ... .. .... 5 2"" . Attached trumpet- or bell-shaped forms ; larg e form s like Stentor (Fig. 20) or small fo rms like some peritrichs Attached flower-like or vase -shaped forms , such as chonotrichs attached to invertebrates .. .... .... .... ..... ...... ..... ... ..... ....... 3. Attached by stalk ..... .. ....... ... ... .... ........ 3 '. Arb oroid lorica attached directly to sub- stratum , not stalked .. ...... (Fig. 4) Marynids, ........ ..... ... ..... ........ (Fig . 5) some sticho 4. Non-contractile stalk .. ..... .... .. ... .... ....... . . . . . . . . . . . . . . . . . . . . . . . . . . Per 4'. Cont ractile stalk .. .... ... . .... . (Fig. 3) Vortic 5. With hyaline lorica attached to sub-stratum without a stalk.. ..... .. .... ..... ... ... .. .... Ch ilodone llids , some peritric hs , and (Fig . 7)heterotrichs 5' . Fo rms with hyaline lo substrat um by a stalk or stalk-like process ... (Figs. 8-1 0) Some peritrichs and suctoria 6. Forms that are long, slender in shape , often flat and ribbon-like ; mostly brackish or marine , such as (Figs . 24 kary orelicteans, (Fig . 27) non-contractile karyorelicteans,.. .. .. .... ... ... .. ...... ....... . . . . . . . . . . . . . . . . . . . . . . (Figs . 28- 6' . Forms that are long , slender in shape, but roun d in cross-section .... .. .... ..... e.g. (Fig . some heterotrichs , (Fig . 32) karyore lict ea ns . CILIOPHORA, KEYS 407 (Fig . 21). .. .. ....... .. (Fig. 22) .. .. .... .. 4 trichs ..... ....... . itrichs such as epistylids ellid (Fig . 6 ) rica attached to -26) contrac tile 24 25 .. ... ......... .. . 31 30) some haptorians 3 1 ) some 408 CILIOPHORA, KARYORELICTEA SUBPHYLUM POSTCILIODESMATOPHORA 1'. O Gerassimova and Seravin , 1976 2. So Ciliates with somatic dikinetids that have b postciliodesmata , a special arrangement of 2'. S overlapping postciliary microtubular ribbons. . They lack parasomal sacs. Oral dikinetids , when present , have their postciliary microtubular ribbons often extending to support the cytopharynx. Oral polykinetids , when present , vary (from two to three rows of kinetosomes , usually with a complex T infraciliature . Polykinet ids of heterotrichs may and m spiral out of the oral cavity onto the body surface naked where they define the peristomal field. The inter extrusomes are mucocysts, rhabdocysts , and/or pigmentocysts . The cortical alveolar system is poorly developed. The oral apparatus of the prot e r usually undergoes regression and redevelopment prior to and/or during cytokinesis. Two classes . 1. b s 9<9 1'. I c 1. Non-dividing , paradiploid macronuclei ; oral polykinetids absent ...... Class Karyorelictea 1' Polyploid macronuclei dividing by involvement of extramacronuclear microtubules ; left serial N oral polykinetids typically conspicuous ..... ...... .. . naked .............. .. ...... .. ............... Class Heterotrichea circu gener CLASS KARYORELICTEA Corliss , 1974 Long , vermiform , flattened ; many genera have one barren surface ; extremely contractile, except Loxodida ; two to many macronuclei contain approximately (sometimes slightly more than) the diploid amount of DNA; macronuclei form by 1. division of micronuclei , then differentiate; the v micronuclei divide , apparently by eumitosis ; three . orders . 1'. W s KEYS TO THE ORDERS OF THE CLASS c b 9<9 2. 1. Oral cilia inconspicuous, or none ....... ..... ... .. ...... . 2' . ... .. ..... .... ........ ... .. ... ... .. Order Protostomatida ral structures not as above .. .... ... .. .... .... ......... 2 matic cilia many, on right surface of flattened ody .. ...... .... ... ........ ... ........... .... Order Loxodida omatic cilia over entire , vermiform body ....... . ............ .... .. .. ..... Order Protoheterotrichida