Ptygura

Ptygura Ehrenberg, 1832 (ref. ID; 7815)

Synonym Oecistes Ehrenberg, 1834 (ref. ID; 1345, 1923, 2572, 2978, 3514, 3688); Pseudoecistes Stenroos, 1898 (ref. ID; 3688)

ref. ID; 1663

Tube made of debris, fecal pellets, or gelatinous and more or less covered with debris. Body length 200 to 1000 microns long. Dorsal antenna small or apparently absent. Ventral (lateral) antennae short to long. Corona a wide oval or nearly circular, indistinctly bilobed. One species free-swimming. (ref. ID; 1663)

ref. ID; 1923

Corona when fully expanded circular or kidney-shaped, with a shallow ventral indentation, but not with both a deep ventral indentation and a wide, deep dorsal gap. Nearly all make definite tubes which are usually gelatinous, sometimes with a fibrous structure. (ref. ID; 1923)

ref. ID; 2762

Flosculariidae with circular, elliptical or weakly bilobed corona, the dorsal gap being at most a small fraction of the total diameter, occasionally absent, and the ventral notch rarely more than a shallow indentation; ventral antennae varying from minute setigerous pimples to greatly elongated, narrow cylinders; dorsal antenna at most a short cylinder, usually a very small pimple; peduncle usually a short cylinder, long in a few species; tube generally gelatinous, cylindrical or irregular, sometimes opaque, reduced or missing in a few species, supplemented by fecal pellets in one species, and consisting of a membranous tube in another; most species sessile; three swim freely permanently or optionally. Of other genera, only Limnias ceratophylli and L. myriophylli are likely to be mistaken for Ptygura, although solitary specimens of Lacinularia flosculosa are confusing. (ref. ID; 2762)

ref. ID; 3334

The corona of this genus is, when fully extended, circular or kidney-shaped, with shallow ventral identation. The margin of the corona is ciliated. The dorsal antenna is small. The mastax has malleoramate trophi. Mostly sessile. Most members of this genus are usually found in a gelatinous tube. (ref. ID; 3334)

Ptygura agassizi Edmondson, 1948 (ref. ID; 2762, 3160 original paper)
Ptygura barbata Edmondson, 1939 (ref. ID; 1345, 2703, 2761 original paper, 2762, 2886, 3259)
Ptygura beauchampi Edmondson, 1940 (ref. ID; 2762, 2833, 3259 original paper) reported year? (ref. ID; 1473, 2640, 3403)
Syn; Oecistes (Ptygura) cf. crystallinus Ehrenberg (de Beauchamp, 1932) (ref. ID; 3259)
Ptygura brachiata (Hudson, 1880) (ref. ID; 2827) or 1886 (ref. ID; 1345, 2597, 2640, 2757, 2762, 2813, 2886, 3514, 3688)
Syn; Oecistes brachiatus Hudson, 1886 (ref. ID; 1345, 2757) or Hudson & Gosse, 1886 (ref. ID; 3688); Ptygura brachiata Harring, 1913 (ref. ID; 1345, 3688)
Ptygura brachiata bispicata (Edmondson) 1944 (ref. ID; 3335)
Ptygura brevis (Rousselet, 1893) (ref. ID; 1345, 2762)
Syn; Oecistes brevis Rousselet, 1893 (ref. ID; 1345); Ptygura brevis Harring, 1913 (ref. ID; 1345)
Ptygura cephaloceros Wright, 1957 (ref. ID; 2993, 3215 original paper) reported author and year? (ref. ID; 2813)
Ptygura cephaloceros grande Koste, 1970 (ref. ID; 2813 original paper)
Ptygura cristata (Murray, 1913) (ref. ID; 2757, 2762) reported year? (ref. ID; 1345)
Syn; Oecistes cristatus Murray, 1913 (ref. ID; 2757)
Ptygura crystallina (Ehrenberg, 1834) (ref. ID; 1345, 1821, 1923, 2276, 2572, 2640, 2757, 2762, 2813, 2827, 3159, 3271, 3591) reported year? (ref. ID; 3160, 3334, 3343, 3688, 5022) reported author and year? (ref. ID; 3292)
Syn; Melicerta crystallina Gosse, 1862 (ref. ID; 1345, 3271, 3688); Oecistes crystallinus Ehrenberg, 1834 (ref. ID; 1345, 2276, 2757, 3271, 3688); Oecistes hyalinus (Ehrenberg, 1838) (ref. ID; 3271, 3688) or 1883 (ref. ID; 1345); Ptygura crystallina Dujardin, 1841 (ref. ID; 1345, 3271, 3688); Ptygura crystallina Harring, 1913 (ref. ID; 1345, 3688)
Ptygura elsteri Koste, 1972 (ref. ID; 2699 original paper, 2703, 2810, 2833)
Ptygura elsteri thailandensis Koste, 1975 (ref. ID; 3083)
Ptygura elsteri f. thailandis Koste, 1975 (ref. ID; 2839 original paper)
Ptygura furcillata (Kellicott, 1889) (ref. ID; 1839, 2064, 2699, 2762, 2833, 3036), furcillata furcillata (Kellicott, 1889) (ref. ID; 3514) reported author and year? (ref. ID; 2702, 2839)
Syn; Cephalosiphon furcillatus Kellicott, 1889 (ref. ID; 2064, 3036, 3514); ?Oecistes ptygura Hudson & Gosse, 1886 (ref. ID; 2064); Ptygura furcata Hauer, 1938 (ref. ID; 2064); Ptygura furcillata Edmondson, 1940 (ref. ID; 3036) or 1949 (ref. ID; 2064)
Ptygura furcillata f. variabilis Koste, 1975 (ref. ID; 2839 original paper)
Ptygura intermedia (Davis, 1867) (ref. ID; 1345, 2757, 2762)
Syn; Oecistes intermedia Davis, 1867 (ref. ID; 1345, 2757); Ptygura intermedia Harring, 1913 (ref. ID; 1345)
Ptygura lacunosa Wright, 1957 (ref. ID; 3215 original paper)
Ptygura libera Myers, 1934 (ref. ID; 1345, 1835, 2545, 2762, 2894)
Ptygura linguata Edmondson, 1939 (ref. ID; 1345, 2761 original paper, 2762, 2834, 3508)
Ptygura longicornis (Davis, 1867) (ref. ID; 1345, 1923, 2640, 2757, 2762, 2827, 3591, 7846) or 1887 (ref. ID; 2833) reported year? (ref. ID; 3343, 5022)
Syn; Oecistes longicornis Davis, 1867 (ref. ID; 1345, 2757); Ptygura longicornis Harring, 1913 (ref. ID; 1345)
Ptygura longicornis var. bispicata Edmondson, 1944 (ref. ID; 2762, 3215)
Ptygura longicornis var. socialis (Weber, 1888) (ref. ID; 1345, 3688)
Syn; Oecistes socialis Weber, 1888 (ref. ID; 1345, 3688); Ptygura longicornis var. socialis Edmondson, 1944 (ref. ID; 1345, 3688); Ptygura socialis Harring, 1913 (ref. ID; 1345, 3688)
Ptygura longipes Wills, 1878 (ref. ID; 1345, 2762, 3688)
Syn; Oecistes longipes Wills, 1878 (ref. ID; 1345, 3688); Oecistes umbella Hudson, 1879 (ref. ID; 1345, 3688); Ptygura longipes Harring, 1913 (ref. ID; 1345, 3688)
Ptygura melicerta (Ehrenberg, 1832) (ref. ID; 1345, 1474, 1806, 2276, 2757, 2762, 3259, 3335, 3688) reported year? (ref. ID; 3334, 3343, 3403, 5022)
Syn; Cephalosiphon furcillatus Kellicott, 1889 (ref. ID; 1345, 3688); Oecistes melicerta Jennings, 1900 (ref. ID; 1345, 3259, 3688); Oecistes ptygura Hudson & Gosse, 1886 (ref. ID; 1345, 2757, 3688) or 1889 (ref. ID; 3259); Oecistes serpentinus Gosse, 1886 (ref. ID; 1345, 2276) or 1889 (ref. ID; 3259), Hudson & Gosse, 1886 (ref. ID; 3688)
Ptygura melicerta var. mucicola (Kellicott, 1888) (ref. ID; 1345, 3335, 3688) or 1889 (ref. ID; 2762, 3259)
See; Ptygura mucicola
Syn; Oecistes mucicola Kellicott, 1888 (ref. ID; 3688) or 1889 (ref. ID; 3259); Ptygura mucicola Harring, 1913 (ref. ID; 3259, 3688)
Ptygura melicerta socialis (Weber, 1888) (ref. ID; 2886), var. socialis (Weber, 1888) (ref. ID; 2285, 2762, 3259, 3271)
Syn; Cephalosiphon furcillatus Kellicott, 1889 (ref. ID; 3271); Lacinularia elongata Shephard (Rousselet, 1913); Oecistes melicerta Jennings, 1900 (ref. ID; 3271); Oecistes ptygura Hudson & Gosse, 1886 (ref. ID; 3271); Oecistes serpentinus Gosse, 1886 (ref. ID; 3271); Oecistes socialis Weber, 1888 (ref. ID; 2285, 3259); Ptygura melicerta Ehrenberg, 1832 (ref. ID; 3271); Ptygura socilais Harring, 1913 (ref. ID; 3259)
Ptygura mucicola Harring, 1913
See; Ptygura melicerta var. mucicola (ref. ID; 3259, 3688)
Ptygura mucicola (Kellicott, 1888) (ref. ID; 3275, 3514)
Syn; Oecistes mucicola Kellicott, 1888 (ref. ID; 3275, 3514); Ptygura melicerta mucicola (Kellicott, 1888) (ref. ID; 3514), var. mucicola Voigt, 1957 (ref. ID; 3275); Ptygura mucicola Berzins, 1967 (ref. ID; 3275)
Ptygura musicola (Kellicott, 1888) (ref. ID; 2699, 2703)
Ptygura pectinifera (Murray) 1913 (ref. ID; 2703, 2762) reported year? (ref. ID; 1345, 2782)
Ptygura pedunculata Edmondson, 1939 (ref. ID; 1345, 2761 original paper, 2762, 2790, 2813)
Ptygura pilula (Cubitt, 1872) (ref. ID; 1345, 1923, 2734, 2757, 2762, 2813, 2827, 3688) reported year? (ref. ID; 3259)
Syn; Melicerta pilula Cubitt, 1872 (ref. ID; 1345, 2757, 3688); Melicerta socialis Collins, 1872 (ref. ID; 3688); Oecistes pilula Wills, 1878 (ref. ID; 1345, 2757, 3688); Ptygura pilula Harring, 1913 (ref. ID; 1345, 3688)
Ptygura rotifer (Stenroos) (ref. ID; 1345, 1923), rotifer rotifer (Stenroos) (ref. ID; 3036)
Syn; Oecistes rotifer van Hofsten, 1909 (ref. ID; 3036); Pseudooecistes rotifer (ref. ID; 1923); Pseudoecistes rotifer Stenroos, 1898 (ref. ID; 3036); Pseudoecistes rotifer Edmondson, 1940 (ref. ID; 3036)
Ptygura rotifer conica Berzins, 1949 (ref. ID; 3036 original paper)
Ptygura seminatans Edmondson, 1939 (ref. ID; 1345, 2761 original paper, 2762)
Ptygura socialis (Weber) (ref. ID; 2276)
Syn; Oecistes socialis Weber, 1888 (ref. ID; 2276)
Ptygura spongicola Berzins, 1950 (ref. ID; 2740 original paper, 3688, 7846)
Ptygura stephanion (Anderson) 1889 (ref. ID; 2762)
Ptygura stygis (Gosse, 1886) (ref. ID; 1345)
Syn; Oecistes stygis Gosse, 1886 (ref. ID; 1345); Ptygura stygis Harring, 1913 (ref. ID; 1345)
Ptygura tacita Edmondson, 1940 (ref. ID; 2703, 2762, 2886, 3259 original paper) reported year? (ref. ID; 1806)
Ptygura tihanyensis Varga, 1937 (ref. ID; 2762) reported author and year? (ref. ID; 1345)
Ptygura tridorsicornis Wright, 1957 (ref. ID; 3215 original paper)
Ptygura tyhanyensis Varga, 1937 (ref. ID; 3688)
Ptygura velata (Gosse, 1851) (ref. ID; 1345, 2276, 2762, 2813, 2894, 3215, 3335, 3508, 3688) reported year? (ref. ID; 3259)
Syn; Megalotrocha velata Gosse, 1851 (ref. ID; 1345, 2276, 3508, 3688); Melicerta ptygura Gosse, 1862 (ref. ID; 1345, 3508, 3688); Oecistes velatus Hudson & Gosse, 1886 (ref. ID; 1345, 2276, 3508, 3688); Ptygura velata Harring, 1913 (ref. ID; 1345, 3508, 3688)
Ptygula volvox Dujardin, 1841
See; Conochilus hippocrepis (ref. ID; 1345, 3688)
Ptygula wilsonii (Anderson & Shephard, 1892) (ref. ID; 2757, 2762)
Syn; Oecistes wilsonii Anderson & Shephard, 1892 (ref. ID; 2757)

Ptygura agassizi Edmondson, 1948 (ref. ID; 2762, 3160 original paper)

Descriptions

The corona is broadly elliptical with a very narrow dorsal gap and no ventral notch. Its plane is at a fairly large angle to the axis of the body, in some positions looks almost perpendicular. The buccal area is large relative to the corona, about half as long as the vertical axis. The cuticular areas lateral to the buccal area are wide and flattened, giving a characteristic appearance to the head in oblique views. The neck is about as long as deep. The body is about four-fifths as wide as the corona, fusiform, widest near the anterior end and tapering gradually to the foot. The dorsum has five or more prominent wrinkles, the most anterior of which encircles the body and separates it from the neck. The foot is heavily wrinkled and is usually about one and a half or two times as long as the rest of the body, but is very extensible and in active specimens may be three times as long. The peduncle is a short cylinder considerably narrower than the foot. The lateral antennae are minute setate cylinders near the ventral side of the neck. On the dorsal side of the neck is a small sharply pointed spine. No setae were observed on it and it is not now possible to decide whether this spine represents a rudimentary dorsal antenna, not whether than organ is absent altogether, and this spine is comparable to that of Ptygura melicerta var. mucicola. A number of mature adults retained the eyes near the dorsal side of the neck, but this was no true of all. The trophi are of the usual type. The first three teeth of the unci are definitely larger than the others. The tube was difficult to observe because the Ruppia to which the animals were attached was covered with a layer of flocculent material containing bacteria and many capsulated algae. Apparently the tubes of the rotifers were short, irregularly shaped and made of rather loose gelatinous material. In addition to the usual tube, the animals were covered by a thin gelatinous layer adhering closely to the cuticle. This cannot be taken as a specific character, for P. crystallina also had such a sheath; possibly this is an effect of salinity. (ref. ID; 3160)

Comments

Ptygura agassizi resembles in a general way P. melicerta, particularly variety mucicola. It differs in the shape of the dorsal spine and lack of any other structure corresponding to the dorsal antenna. The details of the shape of the corona and buccal area are different, particularly in the angle of the plane of the corona to the axis of the body and in the flattened areas at the sides of the buccal area. Moreover, P. agassizi does not have the rigorous substrate limitation of P. melicerta (Edmondson, 1944). One of the specimens corresponded especially closely, except for dorsal spines, with Hudson and Gosse's description of Oecistes serpentinus, generally regarded as a synonym of P. melicerta (Harring, 1913); it was particularly active in contracting foot and corona, had a poorly shaped, small tube, and contained oil globules in the posterior part of the body as did a number of the other specimens. The external morphological characters agreed with those given above. The only other members of the genus which seem to have much resemblance to this are P. tihanyensis and P. stephanion, both of which differ from agassizi in the corona, and lack of a dorsal spine. (ref. ID; 3160)

Etymology

This species is named for the zoologist whose memory was being honored by the biological survey of the island. (ref. ID; 3160)

Measurements

Length 480 µm. (ref. ID; 2762)

Total length 480; foot length 285; corona width 90 µm. (ref. ID; 3160)

Ptygura barbata Edmondson, 1939 (ref. ID; 1345, 2703, 2761 original paper, 2762, 2886, 3259)

Descriptions

Corona rather broad, elliptical, with evident, broad ventral notch; dorsal gap minute; surface of corona furnished with several cuticular processes - a median keel with gentle dorsal slope, abrupt ventral slope, not reaching to ventral edge of corona - a rounded projection at each side of dorsal end of keel - a pair of similar, but pointed projections on ventral edge, farther apart than dorsal ones; buccal area about as long as depth of corona, at right angles to plane of corona, with central tuft of extremely long cilia which wags from side to side; neck well developed; body fusiform, bearing at dorsal anterior end a rounded, bun-shaped process with median groove containing dorsal antenna; foot long, slender; lateral antennae very long, slender, often gracefully curved; anatomy normal; tube fairly narrow, fibro-gelatinous, dark brown in color, quite thin at top; animal sessile. (ref. ID; 2761)

The best morphological characteristic of P. barbata is the dorsal projection between the lateral antennae, which is formed as a bun-shaped process. A peduncle was not visible. (ref. ID; 2886)

The original description (see: ref. ID; 2761) of this species speaks of the median coronal process as if it were a carina. The corona of fixed material often bulges out in the center showing that the process is actually attached only at the dorsal edge of the corona and projecting toward the ventral edge, lying freely over the concave apical area. The process is slightly variable in the profile shape. The superficial resemblance of this species to P. longicornis should be noted. (ref. ID; 3259)

Comments

Ptygura barbata seems most closely related to P. brachiata from which it differs markedly in a number of ways; i.e., the processes on the corona, the peculiar dorsal process, and the unique "chin whiskers'. This beard of long cilia on the buccal area wags from side to side rapidly, but with a rather deliberate motion. In lateral view, it looks something like a flickering flame. (ref. ID; 2761)

Measurements

Length total 305, antennae 40 µm. (ref. ID; 2761)

Length 300 µm. (ref. ID; 2762)

Tube length -400; contracted animal -200 µm. (ref. ID; 2886)

Ptygura beauchampi Edmondson, 1940 (ref. ID; 2762, 2833, 3259 original paper) reported year? (ref. ID; 1473, 2640, 3403)

Synonym

Oecistes (Ptygura) cf. crystallinus Ehrenberg (de Beauchamp, 1932) (ref. ID; 3259)

Descriptions

Corona almost circular, about twice as wide as body; ventral notch absent, at most represented by slight concavity of the margin; dorsal gap distinct, about one-sixth as wide as corona; buccal area rather long, at about right angles to plane of corona; neck parallel-sided; body fusiform, merging gradually into foot; lateral antennae small but conspicuous, conical papillae on sides of neck region at about the level of the mastax; dorsal antenna a minute papilla; tube floccose, gelatinous, usually brown and covered with debris. (ref. ID; 3259)

Comments

Ptygura beauchampi is distinguished from P. crystallina by the location of the lateral antennae on the neck rather than the anterior end of the body itself, by the much wider dorsal gap and the arrangement of the buccal area. After seeing several specimens of this species, one learns to recognize it even with a low magnification by the greater length of the cilia and the much greater rapidity of ciliary action. This gives the corona of the living animals a characteristic appearance which no other Ptygura has. This specie was first found by de Beauchamp on the shells of planorbid snails and described as Oecistes cf. crystallinus. Dr. de Beauchamp has kindly examined sketches of Wisconsin material and says that he believes it is the same species which he found. His specimens had transparent, gelatinous tube, Ptygura beauchampi was one of the two commonest Wisconsin species occurring in 30 of the 109 localities. In Rock Lake (Jefferson County) and Crystal Lake (Dane County) it lived in groups exclusively on the left side of shelled of planorbid snails, but in the lakes of Vilas County it was found on a variety of substrates; in groups on dead, brown, submerged grasses (but not green ones in the same vicinity), on Utricularia, generally in groups and often on the valve of the bladder, and occasionally in colonies of Gloeotrichia. Here the tube is incomplete, covering only the body while the foot projects beyond it into the alga colony. (ref. ID; 3259)

Measurements

Length 460 µm. (ref. ID; 2762)

Length of total 454; length of tube 170; width of corona 85; width of body 45; width of neck 34; width of dorsal gap 15; width of tube 74 µm. (ref. ID; 3259)

Ptygura brachiata (Hudson, 1880 (ref. ID; 2827) or 1886 (ref. ID; 1345, 2597, 2640, 2757, 2762, 2813, 2886, 3514, 3688) or 1880 (ref. ID; 2827)

Synonym

Oecistes brachiatus Hudson, 1886 (ref. ID; 1345, 2757) or Hudson & Gosse, 1886 (ref. ID; 3688); Ptygura brachiata Harring, 1913 (ref. ID; 1345, 3688)

Descriptions

Body slender, with constricted neck region. Trunk going over continuously into the foot, which tapers uniformly and has strong longitudinal striated muscles. The two lateral antennae are cylindrical, long, with a little wart on the end bearing the sensory setae. Corona broad with lip-like thickened rim except for ventral notch, which is deep. Two sides of the notch bear pointed short hooks which in side view resemble two ear-like flaps. Beneath the hooks are to protruding folds which disappear when the specimen is fully stretched. When the corona is folded, only a pursed, protruding knob can be seen. The thick, ciliated oesophagus opens into the large stomach; the stomach is clearly separated from the intestine. Two large gastric glands present; vitellarium vitreous. Dwelling tube clear, colorless. (ref. ID; 2597)

Contracted animals with long lateral antennae and a double pointed blunt hook above the head closure. A very long peduncle unknown in this species resembles P. linguata Edmondson, 1939, but other morphological characteristics are like those of P. brachiata (Hudson), 1886. Determination of the status of this taxon awaits further (uncontracted) material. (ref. ID; 2886)

Measurements

Living specimens; body length 230-260, length of foot 270-320, antennae 38 µm. (ref. ID; 2597)

Length 600-1000 µm. (ref. ID; 2762)

Tubes 792-798; contracted animals 340-420; lateral antennae 35-40; peduncle 170-216; subitaneous egg 36x78 µm. (ref. ID; 2886)

Ptygura brevis (Rousselet, 1893) (ref. ID; 1345, 2762)

Synonym

Oecistes brevis Rousselet, 1893 (ref. ID; 1345); Ptygura brevis Harring, 1913 (ref. ID; 1345)

Measurements

Length 160-200 µm. (ref. ID; 2762)

Ptygura cephaloceros Wright, 1957 (ref. ID; 2993, 3215 original paper) reported author and year? (ref. ID; 2813)

Diagnosis

Large robust Rotifer with strongly ribbed corona twice or more than twice as wide as the body, carrying near its dorsal edge two prominent stiff transparent eminences each surmounted by a blunt horn-like projection; buccal lip bearing a conical flange on each side; minute dorsal gap; papillose cervical and ventral antennae; two prominent permanent eyes, just below the floor of the corona. No dorsal hooks. (ref. ID; 3215)

Descriptions

Ptygura cephaloceros is sessile tube-builder, but its nest is an amorphous mass of matter which collects under the animal's chin and is brought down to the base by its very frequent contractions. Usually the collection of opaque material conceals all but the corona and the neck, but once or twice the writer saw an animal exposed as far down as the intestine, which occupies the normal position. The internal anatomy of this Rotifer appears to be normal. The trophi are strongly developed, with four powerful teeth in each uncus. The first (ventral) tooth on each side has fused with it an accessory tooth whose point rises above the general level. A considerable area in the vicinity of the mastax is strongly tinted with a rusty pink hue. The movements of the trophi are unusually slow and deliberate. In the majority of the Ptygura species the action of the jaws is extraordinarily rapid. Judging by the contents of the faeces ejected by P. cephaloceros. The animal accepts Diatoms (Navicula and Gomphonema spp.) as food. (ref. ID; 3215)

Comments

That this really spectacular Rotifer should have escaped notice may well be due to its having been mistaken of Ptygura velata (Gosse). This error was committed very the writer in 1941 and was discovered only during the past year when, upon comparing his drawing of the new species with sketches made fourteen years earlier, he realised that the animal he had taken to be P. velata was actually that one being described. That first example was found in the author's garden pond in Liverpool, put there unwittingly on some plant transferred probably from one of the fresh water "slacks" or pools on the land side of sand dunes at Freshfield, West Lancashire. During the summer of 1955 numerous specimens were found on submerged moss in a lake on the Cawston Manor estate and also in the Booton pits, and this material made it possible to study the animal closely. While its comparatively great size and general appearance give it a strong resemblance to P. velata, it is to be distinguished at once from that species by the presence on the dorsal moiety of the large saucer-shaped corona of two broad hyaline convexities, one on either side of the median line and extending from the dorsal edge of the corona to its middle. Each of these appears to be supported by curved struts and carries on its outer edge a prominent subconical projection, bent upwards, outwards and forwards towards the ventral rim of the corona. These are seen most plainly when the corona is viewed laterally or ventrally; they are not so distinct from a dorsal aspect unless dark-ground illumination is employed, in which case they are displaced as two short glistening white lines, and the whole of the really magnificent corona shines like a richly-chased silver shield. There is no indication on the corona of the veiling which led Gosse to give the specific name to his Ptygura (= Oecistes) velata. Only two other species of Ptygura bearing coronal processes of the kind herein mentioned have been described, namely P. pectinifera (Murray) and P. cristata (Murray). In each of these species the processes are much more highly developed than in the form taken in Lancashire and Norfolk, and Murray's animals are further distinguished by the presence on the ventro-median edge of the corona of a curious comb-like appendage which is particularly marked in P. pectinifera. In the species found by the writer there is nothing in the nature of a ventro-median pectinate process. Murray found P. pectinifera in a lily pond in Rio de Janeiro and P. cristata in a pond in Sydney, forty-three years ago. It is evident that the new species is in the line of development that has led to the strange forms taken in South America and Australia. The presence of the curious appendages near the apex of the buccal lip brings P. cephaloceros a little nearer to P. pectinifera, but the two are still well separated morphologically, and moreover, Murray believed P. pectinifera to be a free-swimmer, for "when first caught they swam about very violently," and he never saw a tube. (ref. ID; 3215)

Measurements

Measurement of length could not, therefore, be made with any precision, but, assuming the foot of the animal to reach the bottom of the nest, it could in one instance be calculated that the Rotifer was about 400 µm long. This was the largest of all the examples seen, and its coronal disc was 200 µm from the ventral to dorsal edge. The width of the corona could not be measured because of the position of the animal, but it would be greater than the depth. Its body was 90 µm wide. These measurements compare with Murray's figures for P. pectinifera of 130 µm as the width of the corona and 80 µm for the width of the trunk. Typical dimensions of P. cephaloceros found by the writer were; disc 140 µm wide, 110 µm deep; body 70 µm wide. One or two had the disc 170 µm wide and 120 µm deep, and the body 80 µm wide. The differences were due to age, but though the Rotifers did well in shallow receptacles for two months, it was not possible to be sure of the maximum size attainable. (ref. ID; 3215)

Ptygura cristata (Murray, 1913) (ref. ID; 2757, 2762) reported year? (ref. ID; 1345)

Synonym

Oecistes cristatus Murray, 1913 (ref. ID; 2757)

Measurements

Length 320 µm. (ref. ID; 2762)

Ptygura crystallina (Ehrenberg, 1834) (ref. ID; 1345, 1821, 1923, 2276, 2572, 2640, 2757, 2762, 2813, 2827, 3159, 3271, 3591) reported year? (ref. ID; 3160, 3334, 3343, 3688, 5022) reported author and year? (ref. ID; 3292)

Synonym

Melicerta crystallina Gosse, 1862 (ref. ID; 1345, 3271, 3688); Oecistes crystallinus Ehrenberg, 1834 (ref. ID; 1345, 2276, 2757, 3271, 3688); Oecistes hyalinus (Ehrenberg, 1838) (ref. ID; 3271, 3688) or 1883 (ref. ID; 1345); Ptygura crystallina Dujardin, 1841 (ref. ID; 1345, 3271, 3688); Ptygura crystallina Harring, 1913 (ref. ID; 1345, 3688)

Descriptions

Egg: Newly deposited amictic eggs are dark, but they lighten during maturation. Before hatching, red eyespots as well as the ciliated corona and mastax may be distinguished. (ref. ID; 1821)

Larvae: Larvae have a long, worm-like body, divided into three regions: head, trunk, and foot. And they possess a circular wreath of relatively short cilia at the terminus of the head and of the foot. At the anterior end are two red eyespots set widely apart. The head is slightly broader than the trunk. Ganglion, a muscular mastax with well-developed trophi, two stomach glands, and a voluminous intestine are easily seen. These forms also possess red eyespots in the head region, but the lobes or arms of the adult animal are already present inserted inside of the head. Also visible is a large infundibulum, a vestibulum, a large mastax, and an intestine. An anus is usually visible, located in the middle part of the trunk. Larvae possess longitudinal hypodermal glands in the trunk. All internal organs usually obscured by abundant glandular inclusions. A dark oval formation which begins to brighten with the development of the larva is present. This body, which is probably identical to the anisotrophic (birefringent) crystalline structure (ACS) described by Wallace (1993), may function as an energy reserve for swimming and metamorphosis until the young animal begins feed. The foot is usually about 1/3 the total length of the body and contains two very prominent cement glands; the terminal part also contains small bladder-like glands. (ref. ID; 1821)

The dorsal antenna was considerably more conspicuous than usual, and it is not entirely certain that this is indeed crystallina. The tube was fully formed and, in addition, there was a thin gelatinous layer closely adhering to the cuticle of the body. (ref. ID; 3160)

It is a large species, in excess of 500 µm when fully extended. Mucus secretions from the foot glands collect a diverse assortment of debris and epiphytes to form a semi-opaque tube of untidy appearance into which the animal can quickly withdraw. (ref. ID; 3334)

The egg is clear, round or oval, 65 by 50 µm. (ref. ID; 3334)

Measurements

Total length 450-765; tube height 300-600; height at 1st egg 170-220; egg size 66-72x30-39; larval length 96-132 µm. (ref. ID; 1821)

Length 560 µm. (ref. ID; 2762)

Length 500 µm. (ref. ID; 3343)

Ptygura elsteri thailandensis Koste, 1975 (ref. ID; 3083)

Measurements

Body length 120 (contracted); highest part 50 (contracted); hooks 25-30 µm long. (ref. ID; 3083)

Ptygura furcillata (Kellicott, 1889) (ref. ID; 1839, 2064, 2699, 2762, 2833, 3036), furcillata furcillata (Kellicott, 1889) (ref. ID; 3514) reported author and year? (ref. ID; 2702, 2839)

Synonym

Cephalosiphon furcillatus Kellicott, 1889 (ref. ID; 2064, 3036, 3514); ?Oecistes ptygura Hudson & Gosse, 1886 (ref. ID; 2064); Ptygura furcata Hauer, 1938 (ref. ID; 2064); Ptygura furcillata Edmondson, 1940 (ref. ID; 3036) or 1949 (ref. ID; 2064)

Descriptions

The comparatively short body continues in a relatively stout foot. The foot is much longer than body, its ventral side is smooth, but the dorsal side is waved. The foot ends in a toe-like peduncle, with a ring-like enlargement before it. In the head a 48 µm long, conical structure, which on the anterior part terminates in two strong, curved hooks. This hard cone lies in the dorsal part of the body, and only both the above-mentioned hooks with their basic parts are free. The animal was partly contracted, but being very transparent, the large stomach and the vigorous mastax could be seen very well. On the dorsal side, relatively high upon the base of the foot, is the projection of analporus. Trophi of malleoramate type, on one side with two, on other side with three stronger teeth. In ventral view the trophi is asymmetrical. Animal without tube. (ref. ID; 3036)

Comments

The animal is very similar to those found by Hauer in Java, but differs in certain characteristics. My animal is larger (250 µm against 160-170 µm according to Hauer). The hard part of the head is peculiarly formed, and looks like a foreign body in the soft trunk of the animal. The structure of the foot is unusual, especially the caudal part of it. The analporus is strongly developed. A peculiarity is observed also in the trophi (in frontal view), robust teeth being placed in the lower part of trophi, and not in the upper part, as in the Java specimens. It is very possible, that the Ptygura observed by me and the individuals of Hauer belong the different species. The single specimen available was insufficient to answer this question. According to Edmondson, Hauer's Ptygura (?) furcata is identical with Kellicott's Cephalosiphon furcillatus. The article of Kellicott has not been accessible to me, and therefore I have had to accept the Edmondson opinion. Taking this into consideration I have placed the animal observed by me and also those discovered by Hauer according to the classification of Edmondson as Ptygura furcillata (Kellicott). (ref. ID; 3036)

Measurements

Length 170-200 µm. (ref. ID; 2762)

Length 250 µm. (ref. ID; 3036)

Ptygura intermedia (Davis, 1867) (ref. ID; 1345, 2757, 2762)

Synonym

Oecistes intermedia Davis, 1867 (ref. ID; 1345, 2757); Ptygura intermedia Harring, 1913 (ref. ID; 1345)

Measurements

Length 700 µm. (ref. ID; 2762)

Ptygura lacunosa Wright, 1957 (ref. ID; 3215 original paper)

Diagnosis

Trochal disc a narrow oval, often contracted to kidney shape, twice width of body and usually carried with the plane of its surface parallel with the long axis of the animal. Dorsal gap of corona very broad, being equal to the width of the body. Dorsal antenna a minute cylinder; ventral antennae cylindrical, one-third width of body and situated on the neck, level with top of mastax. No dorsal hooks. No eyes. (ref. ID; 3215)

Descriptions

In lateral view the corona appears small and insignificant in proportion to the length of the animal owing to the habit of the Rotifer to contact the organ, causing its depth to approximate only about a third of its width. P. lacunosa often bends backward sharply, making it difficult to see the features of the disc dorsally, but during the brief periods when, after a quick and impatient twist, the animal present the desired aspect, it affords a charming view of the beautiful little disc, with the whole of the trochal ciliation from start to finish of the course, which delights the observer. The ventral antennae are place well up on the neck and are well-developed slightly diverging cylinders, measuring 10 µm in the great majority of a large number of specimens examined, while in one or two examples they were 14 µm long. At the junction between neck and trunk there is a fold, which represents the widest part of the body. Excluding this fold or wrinkle, the sides of the animal from just below the corona to the level of the cloaca are more or less parallel. Ptygura lacunosa is a very active animal, changing its orientation with a jerk, but is not sensitive to normal disturbance. It habitually rises well out of its rough tube, the intestine being usually near or above the top of the nest. Though it contracts at intervals of a few seconds to deposit collections of matter on the pile that thus rises round it, the latter does not appear to become higher than is sufficient to cover the contracted animal. The nest is a more or less conical heap of gritty and floccose material, the upper part being somewhat loose and elastic with a tendency to close upon the withdrawal of the Rotifer. (ref. ID; 3215)

Comments

This is one of the smallest of the tubicolous Rotifers, which may have caused it to be overlooked hitherto or mistaken for the early form of some other species. It is mainly to be distinguished from all the other members of the genus by the great width of the dorsal gap, which is half or more than half that of the corona. This means that when the animal is viewed directly dorsally or ventrally the break in the trochal ciliation can be seen on both sides of the neck at the same time. The only other Floscularian so far described as having a dorsal gap equal to the width of the body is Limnias myriophylli, which the writer has not seen. The two other members of the genus Limnias (L. ceratophylli and L. melicerta) have broad dorsal gaps, but Ptygura lacunosa, though a very much smaller animal, has a dorsal gap whose width not only far exceeds that of the two Limnias spp. in a relative sense but is actually equal to that of a half-grown L. ceratophylli. (ref. ID; 3215)

Locality

Ptygura lacunosa was taken in large numbers on Myriophyllum spicatum and Ranunculus aquatilis from the lake at Havering-land from May to September and occasionally as late as October. (ref. ID; 3215)

Measurements

Average dimensions: Total length of animal 180-200; disc 50-60 wide, 25-30 deep; dorsal gap 30; neck and body 30 wide; body at fold joining neck 32 wide; ventral antennae 10-14 µm long, dorsal antenna very short cylinder. Egg 50 by 26 µm. (ref. ID; 3215)

Ptygura libera Myers, 1934 (ref. ID; 1345, 1835, 2545, 2762, 2894)

Descriptions

The corona is wide, trilobate (Myers describes a circular corona with a dorsal gap) with a ventral indentation and two red apical eyespots. The neck is not constricted, the body tapers into a stout muscular foot ending in a long peduncle. In our specimens the peduncle was surrounded by a transparent ampulle-like tube, not mentioned by a Myers. The inner organization is normal, the trophi malleo-ramate. The animal inhabits a double tube, an inner cylindrical sheath and an outer, normally invisible perfectly clear pyriform test. It is swimming backwards like many planktonic Flosculariidae and Collothecidae. (ref. ID; 2894)

Measurements

Length 300 µm. (ref. ID; 2762)

Total length extended appr. 280; width 64-66; peduncle 30-60 µm. (ref. ID; 2894)

Ptygura linguata Edmondson, 1939 (ref. ID; 1345, 2761 original paper, 2762, 2834, 3508)

Descriptions

Corona broad, almost three times as wide as body, conspicuously bilobed; dorsal gap quite narrow; ventral notch deep, fairly wide, its plane at an acute angle to longitudinal axis of body; buccal area large, projecting a short distance, with cylindrical tongue-like process arising from the gullet; process expanded at tip, well ciliated; neck region well developed, with pair of small, conical projections posterior to chin; body quite narrow, cylindrical, parallel-sided, well set off from foot; foot slender, considerably longer than rest of animal; peduncle long, slender; with pair of large dorsal hooks just posterior to corona, with points opposed, each containing a pear-shaped gland; dorsal antenna a minute cylinder near dorsal hooks; lateral antennae long, extremely slender, arising at sides of body, extending forward; large, hyaline, vacuolated gland present against ventral body wall just posterior to chin; tube quite large gelatinous, transparent, laminated horizontally, often colored, at least in part, golden brown, with dense inner sheath; animal sessile. It was found exclusively on Utricularia, and seems to prefer to live on the bladders of the plant, for only one or two specimens were found on the leaves. It is very timid and hard to observe; it can hardly be induced to expand in anything smaller than a watch glass. (ref. ID; 2761)

The long cases are horizontally laminated, in the upper part stained yellowish, and of relative transparence. All specimens had long stalks with holdfasts. The long and slender lateral antenna are longer than the withdrawn head. On the highest part of the head are two thin and pointed hooks. Jaws have 19(20?) unci. (ref. ID; 2834)

Comments

Ptygura linguata is clearly distinguished from all other species of the genus by the great length of the lateral antennae, character of the dorsal processes and above all, presence of a tongue-like process in the buccal area. (ref. ID; 2761)

Measurements

Length 560 µm. (ref. ID; 2762)

Case length 1200; lateral antennae 85-160; stalk 300; asexual egg 120/45; length of jaws 24 µm. (ref. ID; 2834)

Ptygura longicornis (Davis, 1867) (ref. ID; 1345, 1923, 2640, 2757, 2762, 2827, 3591, 7846) or 1887 (ref. ID; 2833) reported year? (ref. ID; 3343, 5022)

Synonym

Oecistes longicornis Davis, 1867 (ref. ID; 1345, 2757); Ptygura longicornis Harring, 1913 (ref. ID; 1345)

Measurements

Length 350 µm. (ref. ID; 2762)

Length 360 µm. (ref. ID; 3343)

Ptygura longicornis var. bispicata Edmondson, 1944 (ref. ID; 2762, 3215)

Comments

This very striking Rotifer was first recorded by Professor W.T. Edmondson, of the University of Washington, in 1944. In the writer's view, bispicata is a variety of P. brachiata (Hudson) rather than of P. longicornis (Davis), for it shares several prominent characters with P. brachiata, itself very rare. This is in disagreement with Edmondson, who, however, says he has never seen P. brachiata. The drawings given herewith will enable var. bispicata to be recognized and no very detailed description is necessary. The animal forms a cigar-shaped tube which may attain a length more than twice that of the Rotifer's body, and in consequence the occupant's foot is very greatly extended in the taller tubes. It has a beautiful corona with a slight ventral indentation and a wide dorsal gap, below which latter two little hooks are plainly to be seen on the upper part of the neck. The ventral antennae are very long cylinders and the foot ends in a fine-drawn peduncle of varying length, though it appears to be longer in the British form than in the American. (ref. ID; 3215)

Measurements

Length 370-400 µm. (ref. ID; 2762)

In a typical examples the body from the ventral edge of the corona to the junction of body and foot measured 100 µm and the foot 280 µm, the tube 260 µm long. The corona was 50 µm wide, and the length of each ventral antenna 40 µm, i.e., one-third more then the width of the neck. (ref. ID; 3215)

Ptygura longipes Wills, 1878 (ref. ID; 1345, 2762, 3688)

Synonym

Oecistes longipes Wills, 1878 (ref. ID; 1345, 3688); Oecistes umbella Hudson, 1879 (ref. ID; 1345, 3688); Ptygura longipes Harring, 1913 (ref. ID; 1345, 3688)

Measurements

Length 600-1200 µm. (ref. ID; 2762)

Ptygura melicerta (Ehrenberg, 1832) (ref. ID; 1345, 1474, 1806, 2276, 2757, 2762, 3259, 3335, 3688) reported year? (ref. ID; 3334, 3343, 3403, 5022)

Synonym

Cephalosiphon furcillatus Kellicott, 1889 (ref. ID; 1345, 3688); Oecistes melicerta Jennings, 1900 (ref. ID; 1345, 3259, 3688); Oecistes ptygura Hudson & Gosse, 1886 (ref. ID; 1345, 2757, 3688) or 1889 (ref. ID; 3259); Oecistes serpentinus Gosse, 1886 (ref. ID; 1345, 2276) or 1889 (ref. ID; 3259), Hudson & Gosse, 1886 (ref. ID; 3688)

Descriptions

Body long, slender. Corona circular with characteristic notch. Individuals attached to substratum, tubes absent. Eggs elliptical. Foot long, wrinkled; foot glands long, thin. Mastax malleoramate. (ref. ID; 1806)

Corona almost circular, terminal, half again as wide as body; dorsal gap evident but not wide; buccal area large, perpendicular to plane of corona; body fusiform, with two dorsal hook-like processes some distance posterior to corona; foot long, slender; lateral antennae minute papillae on posterior part of neck region; neck separated from body by strong, oblique fold; animal sessile. (ref. ID; 3259)

It is a large species, in excess 400 µm when fully extended. The protective tube usually present in this genus is lacking. (ref. ID; 3334)

Egg: The eggs are brown and ellipsoidal (75 µm by 35 µm). (ref. ID; 3334)

Larvae: The eggs hatch into a free-swimming 'larval stage', which possesses two frontal eyespots that disappear soon after settlement. At the time of settlement, the larvae are 150 µm long. There follows a very rapid increase in the length of the foot and adult size is achieved within 24 hours. (ref. ID; 3334)

Comments

Ptygura melicerta, as described here, is separated from other species by the characteristic arrangement of the buccal area and corona. The type is separated from the two varieties by the presence of two small cuticular spines on the dorsal side of the head posterior to the corona. All specimens I have seen were living in Gloeotrichia colonies, from one to more than a dozen occurring in one colony. There is some doubt that this form actually is the one described by Ehrenberg, especially in the light of some of the variations which have been noted in the literature. In the Wisconsin form, which has also been found in Connecticut, the dorsal spines are small, fairly far from the dorsal gap and point toward the posterior. Now Ptygura melicerta as figured by Ehrenberg looks much like the Wisconsin form, but it has spines which point forward. Moreover, he speaks of the animal as swimming and crawling like a leech. Probably his specimens had simply come loose from the substrate, for his figures certainly do not refer to any of the Ploima or Bdelloids. Later, Eckstein (1883) figured under the name of Ptygura melicerta a sessile form with two large blade-like spines projecting forward from the dorsal side of the contracted animal. Unfortunately Eckstein did not see the corona, but his animal certainly is not the same as that figured here. The species called Oecistes serpentinus by Gosse agrees quite well with the Wisconsin Ptygura melicerta except that the foot is extremely mobile and the hooks point forward. Oecistes ptygura (Hudson & Gosse, 1889) seems to be different from any of the forms mentioned so far, for these is a long bifid process projecting forward as far as the dorsal gap. Still another form was referred to as Oecistes melicerta by Jennings (1900). This had a large, branched, antler-like structure in place of the dorsal hooks. Harring (1913) synonymizes Cephalosiphon furcillatus Kellicott with Ptygura melicerta, but this too many be a distinct form which has been redescribed by Hauer (1938) as Ptygura (?) furcata n. sp. from two localities in Java. None of these forms was found in Gloeotrichia. It will be evident from the descriptions of the two varieties below that the dorsal processes are subject to considerable variation and it may be that the great number of forms described in the literature will fit into the species as provisionally defined here. If it appears later that there are sufficient differences in the forms with large spine which point forward to keep them from P. melicerta as described above, then this form (Wisconsin P. melicerta) will become variety of P. socialis and will need a new varietal name. The form described below as P. melicerta var. mucicola would than become P. socialis var. mucicola. The publication dates of the names socialis and mucicola as given by Harring (1913) are both 1888, but it is evident from a foot-note that mucicola did not go to press until January 4, 1889, while the Zoological Record (1889) shows that socialis appeared in 1888. Therefore, socialis takes precedence. (ref. ID; 3259)

Measurements

Length 200-450 µm. (ref. ID; 2762)

Total length 264; length of body 64; length of foot 200 µm. (ref. ID; 3259)

Length 370 µm. (ref. ID; 3343)

Ptygura melicerta var. mucicola (Kellicott, 1888) (ref. ID; 1345, 3335, 3688) or 1889 (ref. ID; 2762, 3259)

See

Ptygura mucicola

Synonym

Oecistes mucicola Kellicott, 1888 (ref. ID; 3688) or 1889 (ref. ID; 3259); Ptygura mucicola Harring, 1913 (ref. ID; 3259, 3688)

Descriptions

This differs from the type only in the presence of a thorn-shaped structure on the dorsal mid-line just posterior to the dorsal gap. The process shows considerable variation in size, and animals have been collected in which there was only a small knob; thus it grades into the variety described below. It occurs exclusively in colonies of Gloeotrichia. Possibly the forms of P. melicerta described with long processes are exuberant development of this form. (ref. ID; 3259)

Measurements

Length 300-540 µm. (ref. ID; 2762)

Ptygura melicerta socialis (Weber, 1888) (ref. ID; 2886), var. socialis (Weber, 1888) (ref. ID; 2285, 2762, 3259, 3271)

Synonym

Cephalosiphon furcillatus Kellicott, 1889 (ref. ID; 3271); Lacinularia elongata Shephard (Rousselet, 1913); Oecistes melicerta Jennings, 1900 (ref. ID; 3271); Oecistes ptygura Hudson & Gosse, 1886 (ref. ID; 3271); Oecistes serpentinus Gosse, 1886 (ref. ID; 3271); Oecistes socialis Weber, 1888 (ref. ID; 2285, 3259); Ptygura melicerta Ehrenberg, 1832 (ref. ID; 3271); Ptygura socilais Harring, 1913 (ref. ID; 3259)

Descriptions

A circular corona and very long foot were present. A tube was not visible; nor were two minute hooks in the neck under the dorsal corona, an important characteristic of P. melicerta melicerta (Ehrenberg, 1832), Whitelegge (1889) recorded a P. melicerta from N.S.W., however the description is incomplete; the morphologically distinctive presence or absence of hooks in the neck in not mentioned. (ref. ID; 2886)

Comments

This variety differs from the type in having no trace of dorsal hooks or spines. It seems to live mostly in Gloeotrichia colonies. Rousselet (1913) raised colonies of "Oecistes socialis" from dried mud taken from Birket Meskana in Galilee. These were not associated with algae, but lived independently in colonies, secreting gelatinous tubes. It was on this material that Rousselet based the synonymy of Lacinularia elongata with Oecistes socialis. It seems possible that there are two species concerned here; one, the original Oecistes socialis of Weber, which lives in Gloeotrichia colonies and forms no tubes, the other, the Lacinularia elongata of Shephard refound by Rousselet, which lives in large colonies and secretes gelatinous tubes. On the other hand, it may be that when Ptygura melicerta var. socialis occurs in the absence of Gloeotrichia it sometimes grows in large colonies and forms tube, but when it lives among algae tube formation is suppressed. This seems more likely, for Shephard's figures look much like socialis. The status of the Boulder Lake colony remains unknown. It is obvious that the three forms described here, Ptygura melicerta, Ptygura melicerta var. mucicola and P. melicerta var. socialis are sufficiently similar to be included in the same species; the nature of the corona, general shape, size and habitat are similar, the only difference being in the structure of the dorsal process. The point which needs to be settled is the relationship of the type of this species to the one described by Ehrenberg. This can be done if forms with dorsal hooks exactly as figured by him are found. (ref. ID; 3259)

Measurements

Length of specimens approximately 300 µm. (ref. ID; 2285)

Length 370-670 µm. (ref. ID; 2762)

Ptygura mucicola (Kellicott, 1888) (ref. ID; 3275, 3514)

Synonym

Oecistes mucicola Kellicott, 1888 (ref. ID; 3275, 3514); Ptygura melicerta mucicola (Kellicott, 1888) (ref. ID; 3514), var. mucicola Voigt, 1957 (ref. ID; 3275); Ptygura mucicola Berzins, 1967 (ref. ID; 3275)

Comments

In most works, Ptygura mucicola is considered as a bona species. Owing to small morphological differences with Pt. melicerta, Voigt (1957) made of it a "var." of the latter. He was followed by Rudescu (1960). Bartos (1959), however, and Berzins (1967) reverted to the original conception. De Ridder follow the later authors. (ref. ID; 3275)

Ptygura pectinifera (Murray) 1913 (ref. ID; 2703, 2762) reported year? (ref. ID; 1345, 2782)

Measurements

Length 400 µm. (ref. ID; 2762)

Ptygura pedunculata Edmondson, 1939 (ref. ID; 1345, 2761 original paper, 2762, 2790, 2813)

Descriptions

Corona elliptical, with evident ventral notch, somewhat wider than body; dorsal gap absent; neck region definite, heavily wrinkled; body ovate, somewhat depressed, cloacal aperture just below level of lateral antennae; foot cylindrical, short; peduncle slender, longer than foot, often wrinkled; lateral antennae subconical, arising from prominent alate folds of the cuticle, with very long setae; tube large, irregular; animal sessile. (ref. ID; 2761)

Comments

Ptygura pedunculata is clearly distinguished from all other species of the genus by the extremely long peduncle and large lateral antennae. From P. wilsoni it is distinguished by the general details of shape and proportion of the body, corona and antennae. (ref. ID; 2761)

Measurements

Length: total 594, peduncle 231 µm. Width: corona 99 µm. Depth: corona 92 µm. (ref. ID; 2761)

Length 600 µm. (ref. ID; 2762)

Ptygura pilula (Cubitt, 1872) (ref. ID; 1345, 1923, 2734, 2757, 2762, 2813, 2827, 3688) reported year? (ref. ID; 3259)

Synonym

Melicerta pilula Cubitt, 1872 (ref. ID; 1345, 2757, 3688); Melicerta socialis Collins, 1872 (ref. ID; 3688); Oecistes pilula Wills, 1878 (ref. ID; 1345, 2757, 3688); Ptygura pilula Harring, 1913 (ref. ID; 1345, 3688)

Descriptions

This species supplements its tube with fecal pellets. (ref. ID; 1923)

Its corona is elliptical, wide, lateral antennae are cylindrical and elongate. Both foot and the body were visible even in the tube. (ref. ID; 2734)

Comments

This species builds an incomplete tube. The ordinary, gelatinous tube is present, but the pellets may be reduced in number or absent altogether. In such cases it is necessary to use care to avoid confusing this species with P. longipes. (ref. ID; 3259)

Measurements

The specimens encountered in the Muzikantsky rybnik had tubes 520 µm in length and maximally 180 µm in width. The maximum length of the rotifers reached 630 µm, the corona was 140 µm wide and the body 60 µm. The contracted specimen measured 350 µm. (ref. ID; 2734)

Length 400-1000 µm. (ref. ID; 2762)

Ptygura rotifer conica Berzins, 1949 (ref. ID; 3036 original paper)

Descriptions

Animal without tube, free-swimming, or only for a short time anchoring itself to a base. Corona nearly circular, bent obliquely to the long axis of the body. On the dorsal border of the corona is a thickening of the margin which turns inwards bearing two red eyes. These are close together as in the basic specific form. The cilia of the outer ring of the crown are strongly developed, but those of the inner ring are not nearly so pronounced. The dorsal antennae small, with long feeling-setae. Behind the head, on the dorsal side, two pointed conical projections. Body and foot approximately of equal length. Trophi with many small teeth, without any robust ones among them. Foot expressly waved across, with a pipe-like peduncle at the end. In the foot a row of glands. (ref. ID; 3036)

Measurements

Total length 390-410; length of body 190-205; width of corona 75-85; length of trophi 31-36 µm. (ref. ID; 3036)

Ptygura seminatans Edmondson, 1939 (ref. ID; 1345, 2761 original paper, 2762)

Descriptions

Corona elliptical, with minute dorsal gap and slight ventral notch, its plane at angle of 45 degrees to axis of body; buccal area little less than half as long as depth of corona, at angle of about 100 degrees to plane of corona; neck short, narrow, cylindrical; body ovate in dorsal view; venter slightly convex; dorsum gibbous posteriorly, falling off abruptly to foot; foot somewhat more than half of total length, set off from body by deep constriction, with slight, characteristic swelling about two thirds of distance toward tip; peduncle absent; cloacal aperture just posterior to level of mastax; lateral antennae broad, conical, with very long setae, well separated salivary vesicles colorless in recently hatched specimens, orange in fairly young specimens, deep red in older individuals; animal usually sessile in normal tube, without direct connection with substrate, but swims freely. (ref. ID; 2761)

Comments

Ptygura seminatans has no near relative, and is not apt to be confused with any other species. This species makes a hyaline, gelatinous tube on Utricularia, and probably other plants, in which it lies without direct connection with the substrate. While in tube, it sways violently from side to side. When disturbed, as by being collected, it leaves the tube and swims rapidly forward (anterior end foremost). Occasionally there is a spectacular change in form and speed; the foot is completely retracted, the body becoming thick and looking much like a giant Vorticella detached from its stalk. Simultaneously the speed increases so that the animal can hardly be followed with the microscope. It is probably the fastest swimmer of all the rotifers, but may be surpassed by one of the Ploima, Eosophora therina. According to Harring and Myers (1922) this species "can ascend a column of water five inches high in a fraction of a second". When conditions become quite the animal once more settles down to sessile life, forming a new tube. Thus, just after making a collection, the individuals of this species will be found swarming on the lighted side of the vessel, but after an hour, more or less will be found in tubes on the plants. (ref. ID; 2761)

Measurements

Length: total 365, body 145, foot 220 µm. Depth: corona 80, body 70 µm. (ref. ID; 2761)

Length 320 µm. (ref. ID; 2762)

Ptygura spongicola Berzins, 1950 (ref. ID; 2740 original paper, 3688, 7846)

Descriptions

The corona is almost completely circular, with a slight, lightly curved recess on the dorsal edge; it is about twice the width of the body. I did not see dorsal and ventral tentacles, nor warp-shaped ones, hence it must be assumed that they are lacking. On the other hand, two tiny hooks bent down ventrally are to be seen under the corona on the dorsal side. The plane of the corona is slightly inclined dorsally. The trophes are of the general malleo-ramate type, with 5 powerful teeth on each side. The young individuals each have two dark red, almost black, eyes which have disappeared on older individuals. The body is relatively thick-set, slightly tapering towards the abdominal end, and its length is about twice its width. The foot is short, shorter than the body is wide, with a very distinct division between body and leg. The position of the foot is not at the end of the body as is usual with this genus, but somewhat lateral, its juncture being just a little off the body end. The foot is rather slender becoming somewhat broader at its base and terminates, at the distal end, in a tuberous swelling. This distension is stuck in the surface of the sponge like an anchor. The anus is a little below the middle line of the body. The contracted animal is always bent dorsally in a semicircular curve. The length of such an individuals varies from about 190 to 230 µm, the length of the foot from 38 to 43 µm. An extended animal may attain a length of about 220 to 300 µm, its foot - of about 50 to 55 µm. Neither foot nor body is able to stretch out to any considerable extent. The rotifers are devoid of any tube. This species found on sponges. It is no parasite, since it does not injure its host in any way. This commensalism is partly to be regarded as a food competition between host and guest. This sessile species is invariably found in groups on the edges of the oscula and in lesser numbers round the larger pores. In the latter case, a few individuals are scattered round the pore, profiting by the flow of water produced in the direction of the sponge pores, and catching their food there. Around the oscula, on the contrary, the rotifers gathered in large groups, sometimes exceeding the number of 30 individuals around one single osculum. Protruding far beyond the oscular opening, they fish of their food in the water which issus from the sponge. P. spongicola was difficult to observe with its corona open and its body extended to full length. At the slightest disturbance or whenever the water near the pore of the osculum ceased to flow these rotifers would contract. (ref. ID; 2740)

Comments

The animals just mentioned are nearest to the genus Ptygura with which I am disposed to range them. Some features, however, are indicative of a certain proximity also the genus Sinantherina, which does not exclude the possibility of their forming a new genus. However, since it was not possible to carry out more extensive observations on particulars of the structure of the head and corona, in spite of all the great efforts made, it is impossible so far to arrive at a definite conclusion. The rather peculiar form of their body and foot permits of placing these animals within this very well characterized genus. Other species included in the genus Ptygura are not closely related to this one. Their difference becomes yet more apparent when the peculiar biology of the rotifers is taken into account. (ref. ID; 2740)

Ptygura stephanion (Anderson) 1889 (ref. ID; 2762)

Measurements

Length 300 µm. (ref. ID; 2762)

Ptygura tacita Edmondson, 1940 (ref. ID; 2703, 2762, 2886, 3259 original paper) reported year? (ref. ID; 1806)

Descriptions

Corona circular with shallow ventral depression. Lateral antennae long. Foot long, wrinkled. Holdfast long. Rotifer enclosed in gelatinous tube covered with detritus. Characteristic transverse bands due to accumulated detritus. (ref. ID; 1806)

Corona elliptical, with definite, rather deep ventral notch, narrow dorsal gap; buccal area with small knob within ventral margin, bearing long cilia; neck region subcylindrical; body fusiform, tapering gradually to long foot; peduncle very long, slender; dorsal antenna cylindrical, short; lateral antennae very long, slender; tube gelatinous, frequently light brown and laminated, often clear and colorless, always with firm inner sheath. (ref. ID; 3259)

Comments

Ptygura tacita resembles P. linguata very strongly in general shape and appearance, but differs in a number of respects; there are no dorsal hooks, the dorsal antennae is cylindrical and much larger and there is no tongue-like process arising from the buccal area (hence the specific name tacita) although there is a small, ciliated knob in the same position. Another seemingly constant but rather unimportant difference in the shape of the inner sheath of the tube which in P. tacita abruptly decreases in diameter at the anterior end of the peduncle, but tapers gradually in P. linguata. In view of the inconstancy of dorsal processes already demonstrated in Ptygura melicerta, and the existence of a ciliated knob in the buccal area of P. tacita, the validity of the species might be questioned, but since there are several, marked differences and they held in a number of individuals of both species collected from the same locality, it seems unlikely that this is a variety of P. linguata. (ref. ID; 3259)

Measurements

Length 590 µm. (ref. ID; 2762)

Tubes 450-800; peduncle 200-270; subitaneous egg 25x82 µm. (ref. ID; 2886)

Total length 588; length of peduncle 108; length of foot 233; length of lateral antennae 75; length of tube 460; width of corona 102; width of body 52; width of tube 140 µm. (ref. ID; 3259)

Ptygura tihanyensis Varga, 1937 (ref. ID; 2762) reported author and year? (ref. ID; 1345)

Measurements

Length 23-320 µm. (ref. ID; 2762)

Ptygura tridorsicornis Wright, 1957 (ref. ID; 3215 original paper)

Diagnosis

Trochal disc sub circular, rather less than twice width of body; dorsal gap one-seventh width of disc. Plane of disc at right angles to long axis of animal but habitually bent over to ventral side. Cervical antenna very short cylinder; pair of similar antennae situated on dorsum. Setae of all antennae curved posteriorly. No dorsal hooks. No eyes. (ref. ID; 3215)

Descriptions

This species, which appears to be widely distributed and of frequent occurrence, is distinguished by the position of the paired antennae on the dorsum. They are not readily seen for the animal is small and its antennae are ht merest pimples, though the setae are of considerable length. In size and general appearance P. tridorsicornis comes nearest to P. mucicola (Kellicott) but, unlike the latter, it has no dorsal hooks or hook and is not found in colonies of Gloeotrichia, and it has a wider disc. It appears to be solitary species and has been found on various plants, always in large bodies of water and never in ponds. The bending of the animal's corona and neck to the ventral side seems to be due to a stiffening of the cuticle of the neck- a condition seen very markedly in certain members of the genus Limnias, where is that region becomes an inflexible saddle. In P. tridorsicornis this stiffening of the dorsal side of the neck is most noticeable when the Rotifer is in the act of expanding, for as the corona is thrust out the hardened skin of the back of the neck presses the dorsum into a prominent fold or ridge. It is just above that ridge that the paired antennae may be seen if the animal is suitably orientated, below the mastax and midway between the corona and the cloaca. The buccal area is long and forms a steep curve from corona to lip. There is a very extensible foot, much wrinkled transversely. In some examples a segment of the foot just below intestine level formed a stiffened cuff over the part below it. The cloacal orifice pouts permanently perpendicular to the trunk, and in the act of defaecation its only movement is the opening of its external lip. This is characteristic of most sessile Rotifers whose cloaca is above the top of the tube or nest when at rest. In others there is a big displacement of the stomach, intestine and cloaca when excreta is being expelled and the rectum is forced upwards as a long sleeve which delivers the faeces well beyond the top of the tube. This is obviously a provision to present the fouling of the habitation. P. tridorsicornis does not contract frequently, and probably in consequence of this, has a very shallow nest, usually amounting to little more than a shapeless collection of mucus and rubbish just sufficient to cover the eggs. (ref. ID; 3215)

Locality

It was found the writer in the very slightly brackish water of Oulton Broad, Suffolk, in 1948. It occurred chiefly on Myriophyllum spicatum and Ranunculus aquatilis from May to September. (ref. ID; 3215)

Measurements

Average dimensions: corona 70 wide, 54 deep; dorsal gap 10; neck 35 wide; body at fold adjoining neck 40; total length circa 260 to 350 µm. Egg 52 by 34 µm. (ref. ID; 3215)

Ptygura velata (Gosse, 1851) (ref. ID; 1345, 2276, 2762, 2813, 2894, 3215, 3335, 3508, 3688) reported year? (ref. ID; 3259)

Synonym

Megalotrocha velata Gosse, 1851 (ref. ID; 1345, 2276, 3508, 3688); Melicerta ptygura Gosse, 1862 (ref. ID; 1345, 3508, 3688); Oecistes velatus Hudson & Gosse, 1886 (ref. ID; 1345, 2276, 3508, 3688); Ptygura velata Harring, 1913 (ref. ID; 1345, 3508, 3688)

Descriptions

See P. cephaloceros.

Corona wide, flat, circular, faintly ribbed, slightly convex if fully spread, with one dorsal wrinkle. Neck constricted. Trunk variable, slender when extended, tapering into a muscular leg. No pedunculum, although on free-swimming specimens the end of the foot becomes curled. Dorsal antenna is a short truncated cone with terminal ciliation. Ventral antennae hardly visible. Two very small black eyespots on the margin of the corona. Internal organization normal, anus opening on a cylindrical process in the upper third of the trunk. No tube, trophi ramate. (ref. ID; 2894)

Comments

All the specimens examined had large, colorless, gelatinous tubes. All published accounts of this species report the absence of a tube. (ref. ID; 3259)

Measurements

Length 600-700 µm. (ref. ID; 2762)

Total length extended approx. 500; diameter of corona 160; leg 250-270 µm. (ref. ID; 2894)