Operculigera
Operculigera Kane, 1969 (ref. ID; 2014)
Class Oligohymenophora: Subclass Peritricha: Order Peritrichida: Suborder Sessilina (ref. ID; 2014)
[ref. ID; 2014]
Body and lorica similar to Lagenophrys but bearing an operculum which opens anteriorly and ventrally. The posterior half of the lorica hemispherical and divided off from the comparatively flat anterior half by a fold.
Found on freshwater crustacea in Australia.
Quote; Colin R. Curds, Michael A. Gates and David McL. Roberts "British and other freshwater ciliated protozoa Part II Ciliophora: Oligohymenophora and Polyhymenophora" Cambridge University Press, 1983 (ref. ID; 2014)
[ref. ID; 4335]
Emended description; Closure apparatus of lorica aperture consists of flat operculum that covers aperture; operculum attaches to lorica at anterior edge of aperture, opening anteriad and dorsad. Lips of lorica aperture and loricastome absent; lorica aperture consists of simple opening in dorsal surface of lorica. Edge of lorica aperture usually raised slightly above dorsal surface of lorica and thickened. Lorica aperture usually surrounded partially or completely by thickened wall of lorica material that projects vertically from dorsal surface of lorica. Edge of peristomial lip of trophont associated with anteroventral edge of operculum. Thickened myonemal band present in anterior part of edge of peristomial lip. Macronucleus cylindroid, either short or long, and varying in shape and location between species. Second-type asexual division not observed and possibly absent. (ref. ID; 4335)
Remarks; All species of Operculigera that were examined possessed a thickened wall of lorica material around the lorica aperture. This wall is lacking in O. striata (Jankowski, 1986), and Kane (1969) did not mention a wall around the aperture in either species of Operculigera that he described. No species in other lagenophryid genera have a wall around the lorica aperture, although a thickened ridge called the "crescentic thickening" (Willis 1942) partially surrounds the aperture in several species of Lagenophrys. I propose the name vallum (Latin: rampart, palisade) for the wall around the lorica aperture of species of Operculigera. The height and completeness of the vallum varied among the species of Operculigera examined; however, these aspects of its structure are constant within species and constitute reliable taxonomic characteristics. The vallum has one or more spines or blade-like processes projecting from its anterior or lateral edge in some of the species of Operculigera examined. The location, length, and shape of these spines or processes were useful taxonomic characteristics, although they showed more intraspecific variation than the gross structure of the vallum. Most of the species of Operculigera examined had an elongate, curved thickening on each side of the aperture. The shape of these thickening is strongly reminiscent of the hook-like thickenings called "crochets" (Debaisieux 1959) in the anterior lip of many species of Lagenophrys. The anterior half of the operculum was thickened ventrally in all but one of the species of Operculigera examined. The thickened part ends abruptly at its posterior limit, creating a distinct shelf running transversely across the center of the operculum's ventral surface. There was a stout, knob-like process on each side of the operculum in species of Operculigera having a ventral shelf. Only Kane (1969) has described closure of the lorica aperture in living Operculigera, and he stated merely that the operculum opens anteriad without giving any details about its function. The anterior edge of the peristomial lip was associated with the ventral surface of the operculum in all species of Operculigera that were examined. The anterior edge of the peristomial lip grips the ventral shelf of the operculum, wrapping around the processes that project from each side of the shelf. This spatial relationship suggests that Operculigera pulls the operculum down over the lorica aperture by contracting the thick myonemal band in the anterior half of the peristomial lip. Either elastically of the area where the operculum is attached to the lorica or pushing on the operculum by extension of the epistomial disk are possible mechanisms for opening the aperture. The pattern of penicular infraciliature has not been described in any species of Operculigera. I observed the entire penicular infraciliature in only one species of Operculigera, O. parastacis, and parts of it in two other species. Most characteristics of O. parastacis were described adequately by Jankowski (1986); therefore, only its penicular infraciliature need be described here. The three rows of peniculus 3 (P3) are equal in length in O. parastacis; all of them end at the same point near the cytostome. Row 1 of P2 is much longer than the other two rows and extends halfway from the ends of rows 2 and 3 to the cytostome. Rows 2 and 3 of P2 end at the adstomal curvature of P1. P3 begins a moderate distance above the adstomal end of P2 and extends to the cytostome. Row 1 of P3 is grossly shorter than rows 2 and 3, ending only a short distance beyond the adstomal end of P2. In O. asymmetrica n. sp. and O. insolita, P1 and P2 were essentially the same as in O. parastacis. (ref. ID; 4335)
Type species; Operculigera montanea Kane, 1969 by designation (Kane, 1969).
The original description of O. montanea is extremely brief and is unaccompanied by illustrations. A fold that divides the anterior half of the lorica's dorsal surface from the posterior half, and the flatness of the lorica's anterior half are the only distinguishing characteristics of O. montanea given by Kane (1969). The description of the operculum of O. montanea is clear and unambiguous, however, leaving no doubt that the additional species of Operculigera that were found are congeneric with it. (ref. ID; 4335)
[ref. ID; 4396]
An ancestor-descendant relationship between Operculigera and Lagenophrys has been suggested, based on a homology between the vallum of Operculigera and the anterior crescentic thickening in the lorica of many species of Lagenophrys. Features of the lorica aperture, infraciliature of infundibular polykinetids, and life cycle of O. carcini appear to confirm this phylogenetic relationship. Its lack of a vallum, partial thickening of the posterior half of the peristomial myoneme, slender ventral processes of the operculum, approximate equality of length of kinetosome rows in P2, and second type division are all Lagenophrys-like characteristics. Species of Lagenophrys either lack a vallum altogether or retain only a vestige of its (the anterior crescentic thickening). All species of Lagenophrys have the posterior half of the peristomial myoneme thickened, exactly opposite to the condition of the peristomial myoneme in all species of Operculigera except O. carcini. The ventral processes of the operculum of O. carcini are essentially identical to the crochets of many species of Lagenophrys. The kinetosome rows of P2 are equal in length in species of Lagenophrys; thus, the polykinetidal infraciliature of O. carcini is virtually identical to that of species of Lagenophrys that have all three kinetosome rows present in P3. Finally second type division appears to be universal among species of Lagenophrys and may be responsible more than any other characteristic of the genus for its greater success compared to other lagenophryid genera. (ref. ID; 4396)
- Operculigera asymmetrica Clamp, 1991 (ref. ID; 4335 original paper)
- Operculigera carcini Clamp, 1992 (ref. ID; 4396 original paper)
- Operculigera insolita Clamp, 1991 (ref. ID; 4335 original paper)
- Operculigera madagascarensis Clamp, 1992 (ref. ID; 4396 original paper)
- Operculigera montanea Kane, 1969 (ref. ID; 4335)
- Operculigera obstipa Clamp, 1991 (ref. ID; 4335 original paper)
- Operculigera parastacis Jankowski, 1986 (ref. ID; 4335)
- Operculigera seticola Clamp, 1991 (ref. ID; 4335 original paper)
- Operculigera striata Jankowski, 1986 (ref. ID; 4335)
- Operculigera taura Clamp, 1991 (ref. ID; 4335 original paper)
- Operculigera velata Jankowski, 1986 (ref. ID; 4335)
- Operculigera zeehanensis Kane, 1969 (ref. ID; 4335)
Descriptions
Lorica hemispheroidal, suboval or subcircular in dorsal view. Lorica slightly thickened. Vallum completely surrounds aperture. Anterior half of vallum tall, highly arched, symmetrical, with smooth edge. Posterior half of vallum tall to extremely tall, grossly asymmetrical, projecting toward left. Posterior half of vallum usually truncate with smoothly rounded edge, occasionally prolonged distally and tapered to a blunt point. Lateral parts of vallum short. Long strip near base of inner wall of each anterolateral part of vallum heavily thickened to form slightly protruding fold. Rim of lorica aperture heavily thickened. Operculum subcuneate. Anterior half of operculum heavily thickened to form ventral shelf; short, stout, heavily thickened process projecting ventrad from each end of ventral shelf. P1 and P2 of penicular infraciliature as in O. parastacis. P3 not observable because of orientation in body. Macronucleus short to moderately elongate, cylindroid, and located in central or posterior part of left half of body; macronucleus folds into irregular, compact mass. Micronucleus ovoid or fusiform, usually located near center of macronucleus, seldom near either end of macronucleus. (ref. ID; 4335)
Etymology
The specific name refers to the asymmetrical shape of the posterior half of the vallum. (ref. ID; 4335)
Type locality and host
CHILE, Concepcion, Concepcion; 1/14/27; on Parastacus pugnax (Poeppig), bases of gills (NMNH-CC 129881). (ref. ID; 4335)
Type material
A holotype slide (hematoxylin preparation) and two paratype slides (hematoxylin preparations) of material from the type locality will be deposited. An additional paratype slide (protargol preparations) of material collected from a locality near the type locality will be deposited (this slide also constitutes a paratype slide of O. insolita) (ref. ID; 4335)
Operculigera carcini Clamp, 1992 (ref. ID; 4396 original paper)
Descriptions
Lorica hemispheroidal, suboval in dorsal view, moderately longer than wide, with heavily thickened rim. Valleum absent. Rim of lorica aperture not thickened; aperture tilted anteriad at an oblique angle. Operculum suboval, slightly less wide than lorica aperture. Anterior half of operculum not thickened to form shelf on ventral side. Long, slender, subequal, distally tapered processes projecting ventrad from sides of anterior ventral surface of operculum. Anterior half of peristomial myoneme broad, heavily thickened; posterior half of peristomial myoneme noticeably thickened but much less than anterior half. Infraciliature of infundibular polykinetids as follows: rows of P1 approximately equal in length, ending at cytostome. Row 1 of P2 slightly shorter than other rows of P2; P2 ending at adstomal curvature of P1. P3 with three rows; row 1 of P3 much shorter than its other rows, approximately 1/5 their length. All rows of P3 beginning short distance above adstomal end of P2. Row 1 of P3 ending at adstomal curvature of P1; rows 2 and 3 of P3 extending almost to end of P1. Macronucleus elongate, cylindroid, located in approximate center of body or in right half of body, variable in shape. If centrally located, macronucleus nearly spanning width of body; medial part nearly straight or slightly curved and oriented approximately parallel to transverse axis of body, right end thicker than medial part and either curved anteriad away from it, left end thicker than medial part and either curved anteriad away from it or not. If located in right half of body, macronucleus sharply curved or bent with its right arm lying along right edge of body and its left arm extending toward center of body. Micronucleus ovoid, usually located near right end of macronucleus, seldom near center, never near left end. Second-type division present. (ref. ID; 4396)
Remarks
Operculigera carcini was found only on gill lamellae of the host specimens that were examined. Individuals were usually oriented with the apertures of their loricae toward the medial edge of a lamella; therefore, they would have been pointed directly into the respiratory current of the host when they were alive, possibly enhancing the capture of food particles carried in the current. Several structural features set O. carcini apart from other members of its genus: 1) Operculigera carcini has no vallum around its lorica aperture. Not even a vestige of this structure, so prominent in other members of Operculigera, is present in O. carcini. 2) The rim of the lorica aperture is thickened very little in O. carcini, and the posterior half to the rim is flared, raising it above the dorsal surface of the lorica and tilting the entire aperture forward to a noticeable degree. In other species of Operculigera, the rim of the lorica aperture is heavily thickened and level with the dorsal surface of the lorica. 3) The operculum of O. carcini is approximately oval in shape whereas it is cuneate in other members of the genus. 4) The ventral processes of the operculum are long, slender, and tapered to a sharp point in O. carcini. These ventral processes are short, thick, and rounded at the tip in other species of Operculigera. 5) The posterior half of the peristomial myoneme is much thicker in O. carcini than in any other species of Operculigera. 6) Row 1 of infundibular polykinetid 2 is slightly shorter than other rows of P2 in O. carcini, but this row is much longer than other rows of P2 in all other species of Operculigera in which the buccal infraciliature has been examined. In addition to these structural differences, O. carcini differs from other species of Operculigera by undergoing second type division prior to the host's ecdysis. Many individuals in one of the two samples of O. carcini that were examined had divided to form a telotroch and a residual organism, unmistakable evidence of second type division. Second type division is a spherical type of asexual division that occurs as individuals abandon their loricae before ecdysis. Two divisions without an intervening period of growth produce two telotrochs in succession and a nonviable residual organism that remains attached to the lorica and subsequently dies. Despite its atypical features, O. carcini clearly belongs in Operculigera. It has a closure apparatus for the lorica aperture that is fundamentally the same as that of other members of Operculigera, and this is the principal diagnostic characteristic of the genus. (ref. ID; 4396)
Etymology
The specific name is derived from karkinos (Greek; crab) and refers to the host. (ref. ID; 4396)
Type locality and host
Madagascar, central part; on Gecarcinautes goudoti (A. Milne-Edwards), gill lamellae (NMNH-CC catalogue number 19542; host identified as Thelphusa goudoti Milne-Edwards on the specimen label). (ref. ID; 4396)
Type material
A holotype slide (USNM 43099; hematoxylin preparation) and two paratype slides (USNM 43100 and USNM 43101; hematoxylin preparation and protargol preparation) of material from the type locality were deposited in the International Protozoan Type Slide Collection of the National Museum of Natural History, Smithsonian Institution. (ref. ID; 4396)
Operculigera insolita Clamp, 1991 (ref. ID; 4335 original paper)
Descriptions
Lorica hemispheroidal, subcircular or suboval in dorsal view. Lorica rim slightly to moderately thickened. Lateral parts of vallum absent. Anterior half of vallum tall, highly arched, extending farther around aperture at left than at right. Left end of anterior edge of vallum either with long, blade-like process tipped by short, blunt spine or with long, slender spine. Process or spine arising from anterior edge of vallum curves slightly toward left. Posterior half of vallum extremely tall, extending farther around aperture at right than at left; posterior half wide at base, tapering gradually to sharp point. Proximal part of vallum's posterior half slants slightly right; distal part slants sharply to right. Inner wall of each anterolateral part of vallum near base not thickened, without protruding fold. Rim of lorica aperture heavily thickened. Operculum subcuneate. Anterior half of operculum heavily thickened to form ventral shelf; short, broad, heavily thickened knob-like process projecting ventrad from each side of ventral shelf. P1 and P2 of penicular infraciliature as in O. parastacis. P3 not observable because of orientation in body. Macronucleus short to moderately elongate, cylindroid, thick, and located in left half of body. Macronucleus folded into irregular, compact mass. Micronucleus ovoid or fusiform, usually located near the center of macronucleus, seldom near either end of macronucleus. (ref. ID; 4335)
Etymology
The specific name is derived from insolitus (Latin: unusual, uncommon, strange) and refers to the bizarre shape of the vallum. (ref. ID; 4335)
Type locality and host
CHILE, Concepcion, Talcahuano; 9/-/27; on Parastacus pugnax, bases of gills (NMNH-CC 74764). (ref. ID; 4335)
Type material
A holotype slide (hematoxylin preparation) and one paratype slide (protargol preparation) of material from the type locality will be deposited (the protargol slide also constitutes a paratype slide for O. asymmetrica). A paratype slide (hematoxylin preparation) of material from another locality in Chile also will be deposited. (ref. ID; 4335)
Descriptions
Lorica hemispheroidal, suboval in dorsal view, slightly to moderately wider than long; lorica rim slightly thickened. Posterior half of vallum reduced to slightly thickened ridge; remainder of vallum short. Lateral parts of vallum equal in size and proportions, with rounded, moderately arched edge. Anterior half of vallum with level edge and short, broad, angular process on left side. Long strip near base of inner wall of each anterolateral part of vallum slightly thickened, forming slightly protruding fold. Rim of lorica aperture heavily thickened. Operculum subcuneate. Anterior half of operculum heavily thickened to form protruding shelf on ventral side; short, broad, heavily thickened knoblike process projecting ventrad from each side of ventral shelf. Anterior half of peristomial mynoneme broad, heavily thickened; posterior half of peristomial myoneme not noticeably thickened. Infraciliature of infundibular polykinetids as follows: rows of P1 approximately equal in length, ending at cytostome. Row 1 of P2 longer than other rows of P2; rows 2 and 3 of P2 equal in length, ending at adstomal curvature of P1. Row 1 of P2 extending past adstomal curvature of P1, ending at point approximately 1/3 of distance from ends of rows 2 and 3 of P2 to adstomal end of P1. P3 with three rows; row 1 of P3 much shorter than its other rows, approximately 1/4 their length. All rows of P3 beginning short distance above adstomal ends of rows 2 and 3 of P2. Row 1 of P3 ending short distance past adstomal ends of rows 2 and 3 of P2; rows 2 and 3 extending to end of P1. Macronucleus short, cylindroid, located in left half of body, curved or folded into compact mass. Micronucleus ovoid, usually located near center of macronucleus, occasionally near one end of macronucleus or separated from macronucleus by wide distance. Second-type division not observed. (ref. ID; 4396)
Etymology
The specific name refers to the island of Madagascar, the only place here the species is known to occur. (ref. ID; 4396)
Type locality and host
Madagascar, Antananarivo (bought in marketplace); 1/25/63; on Astacoides granulimanus Monod & Petit, gill filaments (NMNH-CC catalogue number 145294; host identified as A. madagascarensis granulimanus Monod & Petit on the specimen label). (ref. ID; 4396)
Type material
A holotype slide (USNM 43094; hematoxylin preparation) and four paratype slides (USNM 43095-43098; one hematoxylin preparation and three protargol preparations) were deposited in the International Protozoan Type Slide Collection of the National Museum of Natural History, Smithsonian Institution. (ref. ID; 4396)
Operculigera obstipa Clamp, 1991 (ref. ID; 4335 original paper)
Descriptions
Lorica hemispheroidal, suboval in dorsal view, and slightly to moderately wider than long. Lorica asymmetrical in dorsal view, with right half moderately larger than left half. Posterior and lateral parts of lorica rim moderately to heavily thickened, abruptly becoming thin laterad of lorica aperture. Posterior half of vallum reduced to slightly thickened ridge; anterior and lateral parts short. Vallum taller at left than at right, sloping gradually from left to right. Edge of vallum without processes. Rim of lorica aperture moderately thickened; protruding folds between rim of aperture and anterolateral portions of vallum absent. Operculum subcuneate in dorsal view. Anterior edge of operculum heavily thickened to form narrow, ventral shelf; ventral shelf smooth, lacking processes. Infraciliature of peniculi was not observed because scarcity of material did not permit protargol preparations to be made. Macronucleus short, cylindroid, and located in approximate center or anterior part of left half of body. Ends of macronucleus curve sharply away from medial part of macronucleus. Micronucleus ovoid, usually located near center of macronucleus and infrequently near either end of macronucleus. (ref. ID; 4335)
Etymology
The specific name is derived from obstipus (Latin: inclined to one side, oblique) and refers to the fact that the vallum diminishes in height from left to right. (ref. ID; 4335)
Type locality and host
AUSTRALIA, New South Wales, Mt. Kosciusko, 1750 m elevation; on Metaphreatoicus australis (Chilton), pleopods (NMNH-CC accession number 34757). (ref. ID; 4335)
Type material
;
holotype slide (hematoxylin preparation) and one paratype slide (hematoxylin preparation) of material from the type locality will be deposited. (ref. ID; 4335)
Operculigera seticola Clamp, 1991 (ref. ID; 4335 original paper)
Descriptions
Lorica ovoid, much longer than wide. Anterior and lateral parts of lorica rim unthickened, posterior part moderately to extremely heavily thickened. Vallum symmetrical, broad in comparison to width of lorica; anterior and posterior halves tall and lateral parts extremely short. Anterior and posterior halves of vallum highly arched, sloping steeply to lateral parts; anterior half slightly taller than posterior half. Edge of vallum without spines or processes. Long strip at base of inner wall of each anterolateral part of vallum moderately thickened, protruding slightly. Rim of aperture heavily thickened. Operculum subcuneate in dorsal view. Anterior half of operculum heavily thickened to form ventral shelf; short, broad, heavily thickened, knob-like process projecting ventrad from each side of ventral shelf. Infraciliature of peniculi was not observed because scarcity of material did not permit protargol preparations to be made. Macronucleus short, thick, cylindroid, located in left half of body, and folded or twisted into an irregular, compact mass. Micronucleus ovoid, usually located near center of macronucleus, seldom near either end of macronucleus. (ref. ID; 4335)
Remarks
Individuals of O. seticola were so numerous on some setae of the host's gills that they almost completely covered them. Most individuals were oriented so that the apertures of their loricae faced toward the tip of the seta to which they were attached. (ref. ID; 4335)
Etymology
The root of the specific name is derived from seta (Latin: bristle) and its suffix from cola (Latin suffix: dwelling in). The name refers to the fact that the species attaches only to setae of the host's gills. (ref. ID; 4335)
Type locality and host
CHILE, Concepcion, Concepcion; 1/14/27; on Parastacus pugnax, setae on bases of gills (NMNH-CC 129881). (ref. ID; 4335)
Type material
A holotype slide (hematoxylin preparation) and one paratype slide (hematoxyline preparation) of material from the type locality will be deposited. (ref. ID; 4335)
Operculigera taura Clamp, 1991 (ref. ID; 4335 original paper)
Descriptions
Lorica hemispheroidal, suboval in dorsal view, with greatest diameter along axis running obliquely from left anterolateral to right posterolateral areas of lorica. Lorica rim heavily thickened. Most of posterior part of vallum reduced to moderately thickened ridge; anterior and lateral parts tall. Anterior half of vallum slopes from left to right; right side of anterior half moderately shorter than left side. Lateral parts of vallum slope steeply posteriad. Most individuals with two long, massive, sharply pointed spines on anterior half of vallum, one on each side; one or both spines occasionally short, with blunt tip. Spine on right with short, blade-like process projecting from anterior part of base. Spines either straight or slightly curved in any direction. Rarely, individuals lack both spines on vallum. Long strip at base of inner wall of each anterolateral part of vallum moderately thickened, protruding slightly. Rim of lorica aperture heavily thickened. Operculum subcuneate in dorsal view. Anterior half of operculum heavily thickened to form ventral shelf; short, broad, heavily thickened process projecting ventrad from each side of ventral shelf. Transverse axis of lorica aperture and operculum not parallel to transverse axis of vallum; in dorsal view, aperture and operculum appear to be turned slightly counterclockwise with respect to vallum. Infraciliature of peniculi was not observed well enough to describe. Macronucleus short, cylindroid, located in left half of body, and folded or twisted into an irregular compact mass. Micronucleus ovoid or fusiform, usually located near center of macronucleus, seldom near either end of macronucleus. (ref. ID; 4335)
Remarks
Individuals of O. taura were usually oriented perpendicular to the long axis of the host's gill filament. They covered many individual filaments almost completely; any filament thus covered was recognizable at once, even under low magnification, by the forest of spines projecting from the loricae of the ciliates. The few individuals of O. taura that had no spines on the edge of the vallum were still indentifiable because of the distinctive shapes of the lorica and vallum. (ref. ID; 4335)
Etymology
The specific name is derived for taurus (Latin: bull) and refers to the similarity between the spines on the vallum and the horns of a bull. (ref. ID; 4335)
Type locality and host
CHILE, Concepcion, Concepcion; 1/14/27; on Parastacus pugnax, gill filaments (NMNH-CC 129881). (ref. ID; 4335)
Type material
A holotype slide (hematoxylin preparation) and two paratype slides (hematoxylin preparations) of material from the type locality will be deposited. A paratype slide (hematoxylin preparation) of material from another locality in Chile will also be deposited. (ref. ID; 4335)