Philasterina

Suborder (1) Philasterina Small, 1967

Syns. Deuterostomatina p.p.,
Pseudocohnilembina

Infraciliature of paroral membrane may show reduced "a" and no "c" segment, while "b" is always clearly present; scutico-vestige separate and posterior to paroral, often in anterior part of distinct director-meridian; mucocysts and mitochondria very prominent; body size generally small; most commonly in brackish or marine habitats, including sand; numerous species freeliving, but number of others occur as inquilines in sea urchins or as commensals in molluscs, coelenterates, annelids, sipunculids, and even the sea horse.

Body elongate to finger-shaped, though small and ovoid in some genera, with anterior end bluntly tapered; life cycle typically monomorphic (but Potomacus exhibits microstome-macrostome transformation); uniform ciliation, generally with single caudal cilium; lengthy, usually shallow, buccal cavity or depression, typically with three (many in Porpostoma) adoral ciliary organelles (sometimes anarchic fields of ciliferous kinetosomes rather than membranelles) arranged more or less in an anteroposterior line in center or left of center of oral area; predominantly freeliving marine forms, though several histophagous on or in sponges, tubularian coelenterates, sea horses, polychaete annelids, crabs (in blood), etc. Family PHILASTERIDAE Kahl, 1931

Body small, elongate-ovoid, sparsely ciliated, with anterior pole conspicuously naked and caudal cilium or cilia at posterior pole; buccal ciliature relatively inconspicuous in long and shallow depression, and "membranelle" number 1 entirely nonciliferous; scutico-vestige bears cilia; in marine or fresh-water habitats, occasionally edaphic. Family URONEMATIDAE Thompson, 1964

Body slender, finger-shaped, tapering to point anteriorly; long caudal cilium; most conspicuous in narrow oral depression is a false "double-membrane" - one membranelle plus adjacent (left side) row of somatic ciliature (n-th kinety); in marine (including Great Salt Lake) habitats. Family COHNILEMBIDAE Kahl, 1933

Body large, flattened laterally, posterior end tapered to tail; dense, uniform somatic ciliation, with single caudal cilium; oral area, with two well-developed membranelles, overhung by frontal lobe of body; inquilinic in widely distributed species of sea urchins, algivorous within host intestine. Family ENTORHIPIDIIDAE Madsen, 1931

Body of medium size, ovoid, dorsoventrally compréssed, with small caudal projection bearing single bristle; buccal ciliature inconspicuous, located anteriorly on ventral surface; inquilines of sea urchins (Entodiscus), commensals in bivalve molluscs (Pectenita), or in esophagus of sipunculids (Cryptochilidium). Family ENTODISCIDAE Jankowski, 1973

Body moderate to large in size, heavily ciliated, commonly with caudal projection bearing one or more longer cilia; buccal organelles shifted posteriorly in some genera, but retain similariry in general morphology and morphogenesis; inquilinic in sea urchins, plus a few species in woodboring molluscs. Family CRYPTOCHILIDAE Berger, n. fam.

Large, ovoid, laterally compressed body, heavily ciliated, with minute caudal projection and prominent anterodorsal suture; large, deep buccal cavity, with somatic(?) kineties on right wall and somewhat reduced buccal ciliature (though membranelle number 2 large); numerous micronuclei, and even more contractile vacuole pores; carnivorous endocommensals of echinoids. Family THYROPHYLACIDAE Berger in Corliss, 1961

Body elongate-ovoid, generally uniformly ciliated, with caudal cilium or cilia and (in some genera) naked apical end; pronounced parateny near anterior end; clearcut postoral suture replacing director-meridian in some species; buccal cavity small, anteroventral, with ciliature reminiscent of Tetrahymena; common polysaprobic forms in fresh-water (occasionally brackish) habitats. Family LOXOCEPHALIDAE Jankowski, 1964

Small to very small, flattened body, ovoid to ellipsoidal (sometimes looking very much like a baseball catcher's mitt!) in shape, with sparse ciliature limited to ventral surface plus one or more long caudal cilia; oral area, sometimes disproportionately large, midventral and much like Tetrahymena (or Dexiotricha, above) in its buccal ciliature; cytoproct occupies all of directormeridian area on foreshortened ventral surface of some species; widespread fresh-water polysaprobic and edaphic forms, with fewer species from brackish or marine habitats. Family CINETOCHILIDAE Perty, 1852

Very small ovoid body, with single equatorial belt of somatic ciliature plus a single long caudal cilium; deep buccal cavity, but oral organelles greatly reduced in number, size, and complexity; common in polysaprobic fresh-water biotopes. Family UROZONIDAE Grolière, 1975

Body small, elongate-pyriform, with sparse somatic ciliature and single caudal cilium; buccal area long and shallow, provided with two distinctive "membranes" on right (two membranelles in tandem plus the paroral); practically all marine (including brackish and halophilic habitats), free-living forms or scavengers, with occasional species inquilinic in echinoids; but fresh-water and coprozoic strains known in one species. Family PSEUDOCOHNILEMBIDAE Evans & Thompson, 1964

Body laterally flattened, uniformly and heavily ciliated; thigmotactic ciliature, on anterior left surface of body, very dense; buccal cavity at or near posterior pole, with reduced and inconspicuous buccal ciliature; symbionts in mantle cavity (or occasionally the slime) of terrestrial (pulmonate) and especially marine (generally bivalve) molluscs, with one species endocommensal in nemertine worm living in bivalve mantle cavity. Family THIGMOPHRYIDAE Chatton & Lwoff, 1926

Incertae sedis in suborder Philasterina
(all monotypic genera except second and third):

Andreula Kahl, 1934;

Aristerostoma Kahl, 1926;

Balanonema Kahl, 1931,

Bizonula Corliss, 1960
(for Bizone);

Cryptostomina Fedele, 1938
(for Cryptostoma);

Eurychilum André, 1910;

Gullmarella Fenchel, 1964
[in family Entodiscidae?] ,

Lembadionella Kahl, 1933;

Protocruzia de Faria, da Cunha & Pinto, 1922
(syn. Protocrucia)
[see remarks under family Spirostomidae
of class Polyhymenophora] ;

Ptyssostoma Hentschel, 1927;

Pusilloburius n. g.
(syn. Pseudoglaucoma p.p.),
type-species P. labiatus (Kahl, 1931) n. comb.
[the genus is defined, in effect, in Kahl's (1931c, pp. 335, 348) description (to save space, not repeated here) of his Pseudoglaucoma labiata; however, Kahl's P. muscorum species, type by (my) subsequent designation (here), remains in his original genus (see family Glaucomidae, order Hymenostomatida)] ;

Rhinodisculus Mansfeld, 1923;

Sertumia Tucolesco, 1962,

Body elongate to finger-shaped, though small and ovoid in some genera, with anterior end bluntly tapered; life cycle typically monomorphic (but Potomacus exhibits microstome-macrostome transformation); uniform ciliation, generally with single caudal cilium; lengthy, usually shallow, buccal cavity or depression, typically with three (many in Porpostoma) adoral ciliary organelles (sometimes anarchic fields of ciliferous kinetosomes rather than membranelles) arranged more or less in an anteroposterior line in center or left of center of oral area; predominantly freeliving marine forms, though several histophagous on or in sponges, tubularian coelenterates, sea horses, polychaete annelids, crabs (in blood), etc.	*Family PHILASTERIDAE* Kahl, 1931**
Body small, elongate-ovoid, sparsely ciliated, with anterior pole conspicuously naked and caudal cilium or cilia at posterior pole; buccal ciliature relatively inconspicuous in long and shallow depression, and "membranelle" number 1 entirely nonciliferous; scutico-vestige bears cilia; in marine or fresh-water habitats, occasionally edaphic.	*Family URONEMATIDAE* Thompson, 1964**
Body slender, finger-shaped, tapering to point anteriorly; long caudal cilium; most conspicuous in narrow oral depression is a false "double-membrane" - one membranelle plus adjacent (left side) row of somatic ciliature (n-th kinety); in marine (including Great Salt Lake) habitats.	*Family COHNILEMBIDAE* Kahl, 1933**
Body large, flattened laterally, posterior end tapered to tail; dense, uniform somatic ciliation, with single caudal cilium; oral area, with two well-developed membranelles, overhung by frontal lobe of body; inquilinic in widely distributed species of sea urchins, algivorous within host intestine.	*Family ENTORHIPIDIIDAE* Madsen, 1931**
Body of medium size, ovoid, dorsoventrally compréssed, with small caudal projection bearing single bristle; buccal ciliature inconspicuous, located anteriorly on ventral surface; inquilines of sea urchins (Entodiscus), commensals in bivalve molluscs (Pectenita), or in esophagus of sipunculids (Cryptochilidium).	*Family ENTODISCIDAE* Jankowski, 1973**
Body moderate to large in size, heavily ciliated, commonly with caudal projection bearing one or more longer cilia; buccal organelles shifted posteriorly in some genera, but retain similariry in general morphology and morphogenesis; inquilinic in sea urchins, plus a few species in woodboring molluscs.	*Family CRYPTOCHILIDAE* Berger, n. fam.**
Large, ovoid, laterally compressed body, heavily ciliated, with minute caudal projection and prominent anterodorsal suture; large, deep buccal cavity, with somatic(?) kineties on right wall and somewhat reduced buccal ciliature (though membranelle number 2 large); numerous micronuclei, and even more contractile vacuole pores; carnivorous endocommensals of echinoids.	*Family THYROPHYLACIDAE* Berger in Corliss, 1961**
Body elongate-ovoid, generally uniformly ciliated, with caudal cilium or cilia and (in some genera) naked apical end; pronounced parateny near anterior end; clearcut postoral suture replacing director-meridian in some species; buccal cavity small, anteroventral, with ciliature reminiscent of Tetrahymena; common polysaprobic forms in fresh-water (occasionally brackish) habitats.	*Family LOXOCEPHALIDAE* Jankowski, 1964**
Small to very small, flattened body, ovoid to ellipsoidal (sometimes looking very much like a baseball catcher's mitt!) in shape, with sparse ciliature limited to ventral surface plus one or more long caudal cilia; oral area, sometimes disproportionately large, midventral and much like Tetrahymena (or Dexiotricha, above) in its buccal ciliature; cytoproct occupies all of directormeridian area on foreshortened ventral surface of some species; widespread fresh-water polysaprobic and edaphic forms, with fewer species from brackish or marine habitats.	*Family CINETOCHILIDAE* Perty, 1852**
Very small ovoid body, with single equatorial belt of somatic ciliature plus a single long caudal cilium; deep buccal cavity, but oral organelles greatly reduced in number, size, and complexity; common in polysaprobic fresh-water biotopes.	*Family UROZONIDAE* Grolière, 1975**
Body small, elongate-pyriform, with sparse somatic ciliature and single caudal cilium; buccal area long and shallow, provided with two distinctive "membranes" on right (two membranelles in tandem plus the paroral); practically all marine (including brackish and halophilic habitats), free-living forms or scavengers, with occasional species inquilinic in echinoids; but fresh-water and coprozoic strains known in one species.	*Family PSEUDOCOHNILEMBIDAE* Evans & Thompson, 1964**
Body laterally flattened, uniformly and heavily ciliated; thigmotactic ciliature, on anterior left surface of body, very dense; buccal cavity at or near posterior pole, with reduced and inconspicuous buccal ciliature; symbionts in mantle cavity (or occasionally the slime) of terrestrial (pulmonate) and especially marine (generally bivalve) molluscs, with one species endocommensal in nemertine worm living in bivalve mantle cavity.	*Family THIGMOPHRYIDAE* Chatton & Lwoff, 1926**

Incertae sedis in suborder Philasterina (all monotypic genera except second and third):
Andreula Kahl, 1934;
Aristerostoma Kahl, 1926;
Balanonema Kahl, 1931,
Bizonula Corliss, 1960 (for Bizone);
Cryptostomina Fedele, 1938 (for Cryptostoma);
Eurychilum André, 1910;
Gullmarella Fenchel, 1964 [in family Entodiscidae?] ,
Lembadionella Kahl, 1933;
Protocruzia de Faria, da Cunha & Pinto, 1922 (syn. Protocrucia) [see remarks under family Spirostomidae of class Polyhymenophora] ;
Ptyssostoma Hentschel, 1927;
Pusilloburius n. g. (syn. Pseudoglaucoma p.p.), type-species P. labiatus (Kahl, 1931) n. comb. [the genus is defined, in effect, in Kahl's (1931c, pp. 335, 348) description (to save space, not repeated here) of his Pseudoglaucoma labiata; however, Kahl's P. muscorum species, type by (my) subsequent designation (here), remains in his original genus (see family Glaucomidae, order Hymenostomatida)] ;
Rhinodisculus Mansfeld, 1923;
Sertumia Tucolesco, 1962,