Panagrellus
Panagrellus Thorne, 1938
Suborder Cephalobina: Family Panagrolaimidae (ref. ID; 3547)
ref. ID; 870
Cuticle with extremely shallow transverse striae less than 1 µm apart, lateral fields with four deeper longitudinal striations at mid-body, fewer anterior to deirid. Head continuous with or only slightly offset from body and with six slightly separated lips. Cheilostom equilaterally hexagonal in cross sections, lining not sclerotized. Prostom partially surrounded with esophageal collar, cross section nearly round, with one ventral and two subdorsal notches, lining conspicuously sclerotized, thicker posteriorly. Stoma triangular behind prostom, dorsal wall slightly protruding with a small central wart. Three narrow dorsal teeth present just behind wart, two pairs subventral teeth borne posterior to dorsal teeth. Shape of stoma increasingly triradiate posteriorly. A circular tube at the end of each arm of esophageal lumen extends between base of stoma and isthmus.
Procorpus 55 to 65% of esophageal length, nerve ring just anterior to basal bulb, hemizonid opposite anterior margin of bulb, deirid at same level on lateral field. Excretory pore between nerve ring and anterior limits of isthmus, excretory duct straight anteriorly, but looped considerably within glands located ventral to posterior half of bulb. (ref. ID; 870)
ref. ID; 3547
Bacterial feeder. (ref. ID; 3547)
- Panagrellus dubius Sanwal, 1960 (ref. ID; 870)
- Panagrellus leucocephalus Steiner, 1936
See; Panagrellus redivivus (ref. ID; 870)
- Panagrellus ludwigii (de Man, 1910) (ref. ID; 870)
- Panagrellus pycnus Thorne, 1938 (ref. ID; 870)
Syn; Turbator pycnus (Thorne, 1938) Goodey, 1943 (ref. ID; 870)
- Panagrellus redivivoides (Goodey, 1943) Goodey, 1945 (ref. ID; 870)
Syn; Anguillula redivivoides (Goodey, 1943) Ruhm, 1956 (ref. ID; 870); Anguillula zymosiphilus Brunold, 1950 (ref. ID; 870); Panagrellus zymosiphilus (Brunold, 1950) Brunold, 1954 (ref. ID; 870); Turbator redivivoides Goodey, 1943 (ref. ID; 870)
- Panagrellus redivivus (Linnaeus, 1767) Goodey, 1945 (ref. ID; 870) reported author and year? (ref. ID; 3547, 5920)
Syn; Anguillula rediviva (Linnaeus, 1767) Stiles & Hassall, 1905 (ref. ID; 870); Anguillula silusiae de Man, 1913 (ref. ID; 870); Cephalobus parasiticus Sandground, 1939 (ref. ID; 870); Chaos redivivum Linnaeus, 1767 (ref. ID; 870); Gordius glutinus Oken, 1815 (ref. ID; 870); Leptodera oxophila Schneider, 1866 (in part) (ref. ID; 870); Panagrellus leucocephalus (Steiner, 1936) Goodey, 1943 (ref. ID; 870); Panagrellus silusiae (de Man, 1913) Goodey, 1945 (ref. ID; 870); Rhabditis glutinus Dujardin, 1845 (ref. ID; 870); Turbator leucocephalus (Steiner, 1936) Goodey, 1943 (ref. ID; 870); Tubator redivivus (Linnaeus, 1767) Goddey, 1945 (ref. ID; 870); Tubator silusiae (de Man, 1913) Goodey, 1943 (ref. ID; 870); Turbatrix rediviva (Linnaeus, 1767) Peters, 1927 (ref. ID; 870); Tubatrix silusiae (de Man, 1913) Peters, 1927 (ref. ID; 870); Vibrio anguillula Muller, 1773 (ref. ID; 870); Vibiro glutinus Muller, 1783 (ref. ID; 870)
- Panagrellus silusiae (ref. ID; 5930)
See; Panagrellus redivivus (ref. ID; 870)
- Panagrellus zymosiphilus (Brunold, 1950) Brunold, 1954
See; Panagrellus redivivoides (ref. ID; 870)
Diagnosis
P. dubius is similar to P. redivivus and P. pycnus. It differs from both species in smaller body size, smaller spicules, and extremely large bifurcation on spicule, and from P. redivivus by the narrower spicule shoulder and main ventral element continuous with bifurcation. (ref. ID; 870)
Descriptions
Stomatal armature not determined. Vaginal lumen straight and anteriorly directed. Spicules medium sized, manubrium usually hooked. Shoulder curved, barely widened. Shaft moderately narrow, sides nearly parallel. Main ventral element continuous with ventral branch of bifurcation. Bifurcation quite wide and long, occupying 18 to 25% of spicule length, both branches straight, without thickenings. Inclusion at terminus of velum possibly present, but not seen because no specimen had spicule protruded. Thin distal portion of gubernaculum about 20% of its length. (ref. ID; 870)
Synonym
Turbator pycnus (Thorne, 1938) Goodey, 1943 (ref. ID; 870)
Descriptions
Vagina anteriorly directed, notch present in lumen as in P. redivivus. Post vulvar sac present. A pair of minute caudal papillae present on anal lips of male tail in addition to papillae described above for all species. Spicules long, comparatively narrow throughout, manubrium angular, slender, hooked. Shoulder angular only slightly widened, shaft very narrow, sides parallel for much of spicule length, but diverging somewhat proximal to beginning of bifurcation. Main ventral element continuos with ventral branch of bifurcation. Bifurcation about 5% of spicule length. Shape of velum not determined because all spicules were either damaged or protruded from anal opening. Thin distal portion of gubernaculum about 15% of length. (ref. ID; 870)
Synonym
Anguillula redivivoides (Goodey, 1943) Ruhm, 1956 (ref. ID; 870); Anguillula zymosiphilus Brunold, 1950 (ref. ID; 870); Panagrellus zymosiphilus (Brunold, 1950) Brunold, 1954 (ref. ID; 870); Turbator redivivoides Goodey, 1943 (ref. ID; 870)
Diagnosis
P. redivivoides, with its short, wide spicule, is easily separated from the other species P. dubius, P. redivivus and P. pycnus. It is most similar to P. ludwigii (de Man, 1910), but in the latter species the vagina is directed anteriorly, and the spicules have a small beak on the manubrium and very short bifurcations.
Brunold separated P. zymosiphilus from P. redivivoides by differences in vaginal cuticularization and in spicule size and shape. Apparently she believed that the vaginal cuticularization of P. redivivoides was thicker on the posterior wall. Helen (1971) shows it to be thicker on the anterior wall, as in P. zymosiphilus. Differences in spicule size and shape could be found in type specimens of both P. redivivoides and P. zymosiphilus. However, no spicules feature could be found consistently in one group and not in the other, whereas spicules from one group could be found which were similar to some in the other group. Therefore P. zymosiphilus is synonymized with P. redivivoides. (ref. ID; 870)
Descriptions
Vagina perpendicular to body wall, otherwise similar to that of P. redivivus. Vaginal cuticularization considerably thicker on anterior wall. Spicules comparatively short, wide. Shape of manubrium variable, trianguloid, not hooked; ventral end of manubria of the two spicules in a specimen much farther apart than dorsal portions. Shoulder quite wide, shaft tapering gradually, sides of shaft parallel for only a short distance. Main ventral element usually irregularly curved at proximal end and extending nearly to dorsal element. Bifurcation about 10 to 15% of spicule length. In one specimen the manubrium of the right spicule was wide, that of the left spicule was quite narrow. Distal thin portion of gubernaculum less than 5% of its length, proximal portion smoothly rounded. (ref. ID; 870)
Panagrellus redivivus (Linnaeus, 1767) Goodey, 1945 (ref. ID; 870) reported author and year? (ref. ID; 3547, 5920)
Synonym
Anguillula rediviva (Linnaeus, 1767) Stiles & Hassall, 1905 (ref. ID; 870); Anguillula silusiae de Man, 1913 (ref. ID; 870); Cephalobus parasiticus Sandground, 1939 (ref. ID; 870); Chaos redivivum Linnaeus, 1767 (ref. ID; 870); Gordius glutinus Oken, 1815 (ref. ID; 870); Leptodera oxophila Schneider, 1866 (in part) (ref. ID; 870); Panagrellus leucocephalus (Steiner, 1936) Goodey, 1943 (ref. ID; 870); Panagrellus silusiae (de Man, 1913) Goodey, 1945 (ref. ID; 870); Rhabditis glutinus Dujardin, 1845 (ref. ID; 870); Turbator leucocephalus (Steiner, 1936) Goodey, 1943 (ref. ID; 870); Tubator redivivus (Linnaeus, 1767) Goddey, 1945 (ref. ID; 870); Tubator silusiae (de Man, 1913) Goodey, 1943 (ref. ID; 870); Turbatrix rediviva (Linnaeus, 1767) Peters, 1927 (ref. ID; 870); Tubatrix silusiae (de Man, 1913) Peters, 1927 (ref. ID; 870); Vibrio anguillula Muller, 1773 (ref. ID; 870); Vibiro glutinus Muller, 1783 (ref. ID; 870)
Diagnosis
P. redivivus, most similar to P. pycnus, can be separated b the shorter spicule with wider, less angular manubrium, wider shoulder and thicker shaft, main ventral element not continuous with ventral branch of bifurcation, and longer thin distal portion of gubernaculum. (ref. ID; 870)
Descriptions
Lateral fields with four parallel lines, the center two closer to each other than to the outer ones; or center lines broken, arranged diagonally. Vaginal lumen flattened dorsoventrally, anteriorly directed, lumen straight except for protrusion of anterior wall fitting into corresponding botch in posterior wall just within vulva. Cuticularization lining vaginal lumen thicker on anterior wall. Dorsal wall with lobe-like thickening present between outlets into ovary and post-vulvar sac, function unknown, comprised of four cells, two on each side, apparently connected to vagina by a duct. Spicules moderately long. Manubrium usually hooked, occasionally trianguloid. Shoulder region widened, with dorsal wall curved, angular, or with intermediate shapes. Shoulder tapering gradually to shaft which has parallel sides for much of spicule length. Main ventral element more or less curved at proximal end, may extend to dorsal wall. Bifurcation 10 to 12% of spicule length, both branches, or only the dorsal branch, slightly thickened anteriorly. Many specimens found with dissimilar spicules within same specimen. Shape of gubernaculum somewhat variable, six or more minute teeth on proximal margin. Thin distal portion 24 to 30% of length of gubernaculum. (ref. ID; 870)
Behavior: Stage-specific behavior. (ref. ID; 5920)
Notes
De Man gave the first description of the sour paste nematode recognizable by modern standards, but, since it was collected from beer mats, presumably he did not connect it with sour paste nematode of Linnaeus and the early microscopits. He gave it the specific epithet silusiae. The next recognizable description of the species, in which Goodey settled the question of the separate identities of the sour paste and vinegar nematodes, was based on specimens actually taken from sour paste. Goodey, considering them to be the same animal often discussed by the early workers, used the specific epithet redivivus. The chief differences found between the descriptions of de Man and Goodey are in the body size and spicule shape. De Man reported longer nematodes than Goodey. As pointed out by Brunold and Ruhm however, body size varies considerably with the nutritive state of nematodes in this genus. In the present study, moreover, considerable size differences were found in specimens from the same population all reared under the same conditions. The spicule shown in de Man's is angular at the shoulder, straight between shoulder and hook, and with a narrow manubrium and small hook. In Goodey's the spicule is curved dorsally between shoulder and hook, and manubrium and hook are thicker than in de Man's specimen. The bifurcations are quite similar in both drawings. Considerable variability was found in spicule shapes in each of the populations studied here; spicules from each population could be found close to the shapes illustrated by both de Man, and Goodey. Slight differences were even found between the two spicules from the same specimen. Neither differences in both size alone, nor the differences in spicule shapes between those described by de Man and Goodey are considered great enough to separate the species, and Ruhm's synonymization of P. silusiae with P. redivivus is accepted herein. Ruhm synonymized P. leucocephalus with P. redivivus; Sanwal disagreed. Syntypes of P. leucocephalus were found to be poorly preserved and quite shrunken, with many flattened, broken specimens. (Steiner reported measurements of L=0.90-0.94 mm for males, 1.00-1.11 mm for females.) On one female the vagina was well enough preserved to show it was quite similar to that of P. redivivus. The spicule, a composite of two spicules, one well preserved distally, the other proximatelly, is similar in shape to some of the P. redivivus spicules. The bifurcations, as well as general body shape and the stoma, are very typical of P. redivivus. The specimens were considerably shorter than the average P. redivivus studied here; only a few P. redivivus specimens were as short. The spicules were much smaller than the smallest spicule found in all the other isolates. No differences but size could be found between Steiner's material and the other isolates and, since shrinkage of the P. leucocephalus specimens could account for some of the difference, and also since size differences alone are not considered of diagnostic value in this genus, P. leucocephalus is synonymized with P. redivivus in agreement with Ruhm. (ref. ID; 870)
See
Panagrellus redivivus (ref. ID; 870)
Descriptions
Free-living nematode. (ref. ID; 5930)