Main Content

The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Resticula

Resticula Harring & Myers, 1924 (ref. ID; 3245 original paper)

Class Monogonontaet: Order Ploimida: Family Notommatidae (ref. ID; 6806)

ref. ID; 1663

With one eyespot, or eyespot absent. Each uncus with one main of tooth and with accessory teeth on either the left or right uncus. Littoral species. (ref. ID; 1663)

ref. ID; 1923

Uncus has 1 principal tooth with 1 to 5 preuncial teeth. Retrocerebral organ consisting of sac alone, no glands. (ref. ID; 1923)

ref. ID; 3245

Notommatid rotifers with very slender, spindle-shaped, illoricate body, nearly cylindric anteriorly and tapering gradually from mid-length to the base of the toes, without reduction in diameter of the foot; the two toes are short and usually have a bulbous enlargement at the base, containing a small mucus reservoir. The corona is frontal or slightly oblique, with a marginal wreath of short cilia and two lateral, auricle-like tufts of long cilia for propulsion; the buccal field is covered with short, close-set cilia. The mastax is virgate and adapted to prehension, but still retains the pumping action unimpaired; the fulcrum is long and slender; the rami are triangular and nearly symmetrical, with a developed tooth; the epipharynx is rudimentary or absent. Two large salivary glands are present. The retrocerebral organ consists of a small, rounded, ductless sac. The eyespot, when present, is a loosely aggregated mass of red pigment granules, diffusing among the vacuoles of the sac. (ref. ID; 3245)

ref. ID; 3334

A small genus of illoricate notommatid rotifes. The mastax is not removed from the corona. The retrocerebral organ lacks glands and consists of just a sac. The mastax has modified virgate trophi. The uncus has one principal and between one and five preuncial teeth. The foot is well-developed and carries two short, strong toes. (ref. ID; 3334)
  1. Resticula anceps Harring & Myers, 1924 (ref. ID; 1345, 2017, 3245 original paper)
  2. Resticula gelida Harring & Myers, 1922 (ref. ID; 1345, 2017, 2266, 2608, 2894, 3245, 3688, 7846) reported year? (ref. ID; 3334, 3397)
    Syn; Eosphora gelida Harring & Myers, 1922 (ref. ID; 1345, 2017, 3245, 3688); Resticula gelida Harring & Myers, 1924 (ref. ID; 1345, 2017, 3688)
  3. Resticula lestes Wulfert, 1935 (ref. ID; 1345, 2017)
  4. Resticula melandocus (Gosse, 1887) (ref. ID; 1345, 1923, 2017, 2268, 2640, 2757, 2796, 3245, 3271, 3688) or 1897 (ref. ID; 7846) reported year? (ref. ID; 2890)
    Syn; Eosphora melandocus Harring & Myers, 1922 (ref. ID; 1345, 2017, 3245, 3688) or (Gosse) Harring & Myers, 1921 (ref. ID; 3271); Furcularia melandocus Gosse, 1887 (ref. ID; 1345, 2017, 2757, 3245, 3271, 3688); Notommata melandocus Harring, 1913 (ref. ID; 3245, 3271, 3688) or Harring & Myers, 1922 (ref. ID; 1345); Resticula melandocus Harring & Myers, 1924 (ref. ID; 1345, 2017, 3688)
  5. Resticula nyssa Harring & Myers, 1924 (ref. ID; 1345, 1499, 2017, 2266, 2268, 2841, 3245 original paper, 3688) reported year? (ref. ID; 3403)
  6. Resticula plicata Wulfert, 1935 (ref. ID; 1345, 2017, 2702, 2814, 3688)
  7. Resticula vermiculus Wulfert, 1935 (ref. ID; 1345, 2017, 3688)

Resticula anceps Harring & Myers, 1924 (ref. ID; 1345, 2017, 3245 original paper)

Descriptions

The body is elongated, spindle-shaped and very slender; its greatest width is about one fifth of the total length. The integument is very flexible and the outline is constantly changing in response to the contractions of the animal. The entire body is very transparent. The head and neck segments are of about equal length and width, approximately three fourths of the greatest width of the body. The transverse folds limiting the two anterior segments are well marked. The abdomen is very nearly parallel-sided for half its length; from there it tapers very gradually to the base of the foot, ending in an indistinct, broadly rounded tail. The foot continues the general outline of the body without any marked reduction; it has two joints, the proximal very large and tapering to the short terminal joint. The toes are short and conical; their external margins are slightly curved and the inner straight; their length is about one twentieth of the total length. The dorsal and lateral antennae are small setigerous papillae in the normal positions. The corona is slightly oblique and consists of a marginal wreath of cilia, closed on the ventral side immediately below the mouth; laterally there are two strong, auricle-like tufts especially adapted to swimming. The buccal field is covered with short, close-set cilia; the small apical plate is unciliated. The mastax is virgate, but of a modified type although it still retains the pumping action seemingly unimpaired, the unci may be used for prehension. The fulcrum is very long and slender slightly incurved and expanded at the posterior end for the attachment of the muscles of the piston. The rami are broadly triangular in ventral view and have large, somewhat asymmetric alulae with a complicated system of reenforcing ribs. The basal apophysis is prominent and very broad; behind this there is a large oval ventral opening between the rami, continuing to the point where the teeth of the unci normally rest. The dorsal, curved portion of the rami is deeply striate and obtusely dentate on its inner margin. The unci have a very small, subsquare basal plate, traversed diagonally by a rudimentary tooth, finely striate at this tip; only one tooth in each uncus is functional. Five or six very short accessory teeth are attached to the tip of the left uncus, but none to the right. The central section of the manubrium tapers gradually to the posterior end; the basal plate is somewhat pentagonal in outline. A slender, curved rod is imbedded in the walls of the mastax on each side just below, and parallel to, the posterior edge of the ramus; these rods assist in the support of the mastax during the pumping action. The salivary glands are very large and nearly of the same size. The oesophagus is slender and moderately long. The gastric glands are very small. A slight constriction separates the stomach from the intestine. The ovary and bladder are normal. The foot glands are small and pyriform; they discharge into a very small spherical mucus reservoir at the base of the toes. The ganglion is large and saccate. The retrocerebral sac is fairly large, pyriform and vacuolate; it does not appear to contain bacteroids. No subcerebral glands are present. The eyespot is a huge, lens-shaped disc attached to the posterior end of the ganglion; its diameter is two thirds of the width of the ganglion itself. (ref. ID; 3245)

Comments

Its nearest relative is R. nyssa, but it is readily recognized by its smaller size, the form of the corona and the eyespot, as well as the simpler toes. (ref. ID; 3245)

Type locality

Resticula anceps is rare; we have only found a few specimens in a boggy area along Helen Creek, near Mamie Lake, Vilas County, Wisconsin. (ref. ID; 3245)

Measurements

Total length 250-300; toes 12-15; trophi 45 µm. (ref. ID; 3245)

Resticula gelida Harring & Myers, 1922 (ref. ID; 1345, 2017, 2266, 2608, 2894, 3245, 3688, 7846) reported year? (ref. ID; 3334, 3397)

Synonym

Eosphora gelida Harring & Myers, 1922 (ref. ID; 1345, 2017, 3245, 3688); Resticula gelida Harring & Myers, 1924 (ref. ID; 1345, 2017, 3688)

Descriptions

Our animals were not as slender as drawn by Harring & Myers and had an indication of a tail. The longitudinal rows of small dots were not seen (cf. Voigt 1957). The structure of the trophi is however unmistakable, especially the lateral view of the fulcrum. (ref. ID; 2894)

A large, red eyespot is present on the brain. (ref. ID; 3334)
  • Egg: Eggs are large, brown and circular (90 µm in diameter). (ref. ID; 3334)

    Comments

    It is closely related to R. melandocus, especially in the structure of the mastax. (ref. ID; 3245)

    Measurements

    Length 230-240; width 90 µm. (ref. ID; 2894)

    It is a large species, up to 400 µm long. The trophi range from 57 to 60 µm in length. The Signy specimens agree closely with the published descriptions, being the maximum size specified by Harring & Myers (1922). The trophi are slightly larger than those of the original specification but compare favourably with Koste (1978), who recorded trophi of 60 µm in specimens 384 µm long. Wulfert (1936) recorded specimens that were 600 µm with trophi of 75 µm. (ref. ID; 3334)

    Resticula nyssa Harring & Myers, 1924 (ref. ID; 1345, 1499, 2017, 2266, 2268, 2841, 3245 original paper, 3688) reported year? (ref. ID; 3403)

    Descriptions

    The species has the very long alulae on the rami showing two sharp pointed ends. When the trophi are pressed, pleural-rods with fan-shaped feathery ends, and supramanubria can be observed. The fulcrum is long, slender, and the end is bent ventrally. (ref. ID; 1499)

    The body is elongate, spindle-shaped or subcylindric and very slender; its greatest width is only one sixth of the total length. The integument is very flexible and the outline changes with the contortions of the animal. The body is transparent. The head segment is rounded anteriorly and this portion is separated from the head proper by a slightly constriction; it corresponds to the rostrum of other Notommatids. The length of the neck segment is a little greater than its width; the transverse folds limiting it anteriorly and posteriorly are well marked. The abdomen is very nearly cylindric; it is longitudinally striate and has three indistinct, transverse folds. The tail is quite prominent, short and very broad. The foot has two very short, broad joints of about equal length. The toes have a large basal, bulbous enlargement, similar to, but smaller than R. melandocus; the posterior half is conical, acute and slightly decurved. A very faint transverse line separates the basal bulb and the clawlike tips of the toes; their length is about one twentieth of the total length. The dorsal antennae is a small setigerous papilla in the normal position; the lateral antennae have not been observed. The corona is virtually ventral and consists of a simple, evenly ciliated oval are without any auricles or any cilia specialized for swimming. The mouth is near the posterior edge. The mastax is virgate with modification adapting it for prehension. The fulcrum is long and slender, slightly incurved and expanded the posterior end for the attachment of the muscles of the piston. The rami are roughly triangular in ventral view and have large asymmetric alulae. The basal apophysis is very prominent; above this there is a large oval ventral opening between the rami. At the apex of the rami there are three or fourth very small teeth, traceable for some distance from the inner edges of the rami as faint striae. The dorsal portion of the rami is marked with a marginal band of fine, closely spaced, convergent striae; near the dorsal tips there appears to be complete fusion of the rami. The unci have two teeth each; the ventral tooth is well developed, but not clubbed at the tip. The second tooth is strongly curved and only half the length of the main tooth; it rests in a well marked depression or socket in the ramus and evidently serves only as a hinge for the entire malleus. Five accessory teeth are attached to the tip of the left uncus; there are none on the right side. The basal plate of the manubria is rather small and rounded; the central portion is long and slender, somewhat irregularly curved and tapers gradually towards the posterior end. The slender reenforcing rods imbedded in the walls of the mastax of so many Notommatids are in this species fibrillate at the ends and fused to the rami. The piston is very large and powerful and, as far as can be judged from the structure of the mastax, the pumping function is of primary importance and prehension secondary. The salivary glands are very large and of the same size. The oesophagus is very long and slender. The gastric glands, ovary and bladder are normal. There is no distinct separation between stomach and intestine. The foot glands are small and pyriform; a minute mucus reservoir may be concealed in the basal enlargement of the toes. The ganglion is large and saccate; the spherical, ductless, vacuolate retrocerebral sac is attached to its posterior end. No subcerebral glands are present. There is no true eyespot; the anterior portion of the sac is filled with a mass of red pigment granules, diffusing among its vacuoles, but not enclosed in any capsule. (ref. ID; 3245)

    Comments

    Its nearest relatives are R. melandocus and R. anceps; it is readily recognized by its large size, slender body and the very simple, ventral corona, as well as the structure of the eyespot. (ref. ID; 3245)

    Type locality

    Resticula nyssa has been found only at Bargaintown, near Atlantic City, New Jersey. (ref. ID; 3245)

    Measurements

    Total length 300-350; toes 14-18; trophi 50 µm. (ref. ID; 3245)