Opusc. Zool, Budapest, XXI, 1985

On the Genera Mononchus Bastian, 1865 and Prionchulus (Cobb, 1916) Wu & Hoeppli, 1929 (Nematoda: Mononchidae)



Abstract. The nematode genera Mononchus Bastian, 1865 and Prionchulus (Coss, 1916) Wu & HogrpLi, 1929 are discussed and their species enumerated. Mononchus bellus and Prionchulus aurtius n. spp. are described as new to science. Keys to the species of both genera are added.

In this paper I give the descriptions of two new species of the nematode family Mononchidae, and, by seizing the opportunity, I present some pictures on the genera Mononchus BASTIAN, 1865 and Prionchulus (Cops, 1916) Wu & HoEPPLI, 1929.

Genus Mononchus Bastian, 1865

Mononchidae, Mononchinae. Body varying in length from 0.9 to 5.6 mm. Buccal cavity oblong, oval, armed with a large dorsal tooth lying in the anterior third of the mouth cavity and pointing forward. Opposite to the tooth a fine transverse rib on each subventral walls is present. Proximal end of oesophagus simple, non-tuberculate. Female gonads paired; vulva situated in the mid-body region, Males described for most species, with 10—40 ventral supplementary organs. Tails of both sexes similar, more or less elongated. Caudal glands well developed and opening terminally.

Predominantly aquatic animals; predators, devouring their preys in toto.

Type-species: Mononchus truncatus BASTIAN, 1865.

Eleven species may be listed here:

M. aquaticus CoETZEE, 1968 Syn. Mononchus macrostoma apud MEYL, 1955 Mononchus longicaudatus apud WILLIAMS, 1958 Mononchus truncatus apud MULVEY, 1967, partim: “small female” Mononchus truncatus apud MULVEY & JENSEN, 1967 Mononchus sinensis Sont & Nama, 1983

* Dr. Istvén Andrássy, ELTE Allatrendszertani és Ökológiai Tanszék (Department of Syste- matic Zoology and Ecology of the Eötvös Loránd University), 1088 Budapest, Puskin-u. 3.


M. bellus n. sp. Syn. Mononchus truncatus apud COETZEE, 1968 M. clarki ALTHERR & DELAMARE DEBOUTTEVILLE, 1972 M. italicus ANDRÁSSY, 1959 Syn. Clarkus italicus (ANDRASSY, 1959) JAIRAJPURI, 1970 M. maduei SCHNEIDER, 1925* M. mulveyi n. nom. Syn. Mononchus maduei apud MULVEY, 1978 M. niddensis SKWARRA, 1921 M. scutarius EROSHENKO, 1972 M. superbus MULVEY, 1978 M. truncatus BASTIAN, 1865 Syn. Mononchus macrostoma BASTIAN, 1865 Mononchus longicaudatus Cops, 1893 Mononchus macrostoma var. longicaudata Cops, 1893 (MICOLETZKY, 1922) | Mononchus macrosioma var. armala DADAY, 1897 Mononchus dadayi MICOLETZKY, 1914 Jotonchus dadayi (MICOLETZKY, 1914) ALTHERR, 1960 Miconchus dadayi (MICOLETZKY, 1914) MULVEY, 1962 Mononchus tenuicaudatus STEFANSKI, 1914 Mononchus megalaimus COBB, 1917 Mononchus brevicavatus KREIS, 1924 Mononchus fusiformis EROSHENKO, 1972

M. tunbridgensis Bastian, 1865

The following taxa must be regarded as species inquirendae: M. allgeni MEYL, 1957 Syn. Mononchus sp. apud ALLGÉN, 1933 M. macrostoma var. filicaudata SCHNEIDER, 1937 M. macrostoma var. pseudoparva MICOLETZKY, 1922 M. obtusus Cons, 1917

The genus Mononchus is distributed over the world except the Antarctic. Europe is represented by 7 species, Asia by 4, Africa by 3, North America by 7, Central and South America by 5 and Australia by 2 species. The most common species is M. (runcatus: it has been recorded from 39 countries or states hitherto. It is followed by M. tunbridgensis (from 14 countries or states) and M. aquaticus (from 11 countries or states). Five of the species have not been found since their first description.


Mononchus aquaticus. Although this species was described by COETZEE in 1968 we may be convinced that some former data in the literature also referred to it; thus, “M. macrostoma” of MEYL (1955), “M. longicaudatus” of WILLIAMS (1958), the ‘small female” of M. truncatus drawn by MULVEY (1967, Figs. 18 and

* The recently described Mononchus angarensis GAGARIN, 1984 is very similar to M. mvduet (the same species ?).


20), and “M. truncatus” of MULVEY and JENSEN (1967). Mononchus aquaticus can be distinguished from its sister species, M. truncatus, by the smaller buccal cavity (27-31 X13—16 wm: 45 —50 X18— 22 um) and the apex of the dorsal tooth situated more anteriorly (in 19—23% : 22— 289).

Mononchus bellus. The “M. truncatus”? mentioned by COETZEE in 1968 is identical with M. bellus. Mononchus clarki. This short-tailed species is unique within the genus in

having a subterminal-subdorsal opening for the caudal glands. In other respects, including the structure of the mouth cavity, it is a true Mononchus.

Mononchus italicus. This interesting species was described by me from Italy (ANDRÁSSY, 1959). Since it had a very short tail, JAIRAJPURI (1970) trans- ferred it in the genus Clarkus. I cannot agree with him: the shape and structure of the buccal] cavity are different from those of Clarkus and wholly correspond for the characteristics of Mononchus. The single feature by which M. italicus differs from every other representative of the latter genus is the opisthodelphy of genital apparatus of the female. Unfortunately, I described this species on the basis of a single female (and a juvenile) and could not decide with certainty whether monodelphy was an individual extraordinary feature or a constant specific character.

Mononchus mulveyt. MULVEY (1978) described a species from Canada under the name ‘‘Mononchus maduei” which, however, distinctly differs in the shape of the tail from that. While M. maduei has a short and plump tail hardly narrowing to its tip and broadly rounded, the tail of the Canadian species is longer, bent ventrally and finger-like in its posterior third. MULVEY’s specimens represent in my opinion a distinct species for which I propose the name M. maul- veyt,

Mononchus scutarius. Maybe that it is identical with M. truncatus. In the measurements, length of the mouth cavity (44 wm) and position of the apex of the dorsal tooth (20%) it agrees well with ¢runcatus but the labial papillae seem to be smaller and the vulval lips somewhat more protruding.

Key to the species of Mononchus

1 Body large, females 2.7-5.6 mm ............................,....2. 2

Body smaller, females 0.9—2.2 mm ................................. 5 2 Tail short, 2.5 —3 times anal body diameter (e = 15— 20); males with 22 26

Supplements: si... ds ae ae ah enh ne RE 3

Tail longer, 4—5 times anal body diameter (c = 12-15); males with 33 40 supplements: 255 tu pe ren ea ne er 4

3 Tailterminusin both sexes digitiform, ventrally bent. © : L = 2.8 —3.4 mm;

a = 35—44; b = 28-33; c = 16—20; V = 50-60% d:L = 2.7—3.0 mm;

= 30-33 b = 3.1-3.3; 0 = 20—23, (Canada.) .............,........ mulveyi n. nom.

Tail terminus in both sexes plump, broadly rounded, tail straight. ©: L = 3.5-3.7 mm; a = 24-29; b = 4.0— 4.4; ¢ = 18-20; V = 55— 59%. g: L = 3.6 mm; a = 28; b = 4.2; c = 27. (Federal Republic of Germany.) maduei SCHNEIDER







Body very long, 5 mm or more; apex of dorsal tooth in 23 24%, of the buccal cavity; female tail about 400 um long. 9: L = 5.0—5.6 mm; a = 44-47; b=38-45; e = 13; V = 51-53%. g: L = 4.5-6.0 mm; a = 39—46; b = 40-4.6;c = 19—24. (Canada.) ............................,..... superbus MULVEY

Body 3.5 mm or shorter: apex of dorsal tooth in 12—17% of the buccal cavity; female tail about 200 um long. 9: L = 2.7-3.5 mm; a = 32—43; b = 3.8—4.2;¢ = 12—15; V = 51-54%. 9: L = 3.1mm;a = 36;b = 3.7; c = 17. (Federal Republic of Germany, Czechoslovakia, Poland, Denmark, Soviet Union [Russia], Canada.) ...............................,....... niddensis SKWARRA

Female monodelphic, ovary posterior to vulva; tail short and plump. ©:

L = 1.1 mm;a = 28;b = 3.7;¢ = 15; V = 54%. g unknown. (Italy.) italicus ANDRASSY

Female didelphic; tail generallv long, exceptionally short .............. 6

Tail very short, 1.5 times anal body diameter, bluntly rounded; spinneret of caudal glands subdorsal. 9: L=18 mm; a = 25; b = 3.5; c = 33; V = 59-60%. g unknown. (United States [Massachusetts].) ..............

clarki ALTHERR & DELAMARE DEBOUTTEVILLE Tail elongated, 5 to 12 times anal body diameter; spinneret of caudal glands terminal... 0... eee tne nee eens 7

Buccal cavity small, 18 20 um long, its walls nearly straight; apex of dorsal tooth close to the beginning of the buccal cavity; body short, about 1 mm. 9: L = 0.9-1.2 mm; a = 20-31; b = 4.2—5.0; ce = 8.3— 10.3; V = = 51-55%. § unknown. (Holland, England, Switzerland, Czechoslovakia, Soviet Union [Russia, Georgia], India, Japan, South Africa, Canada, United States [ Alabama, Virginia], Surinam, Australia.). ........................

tunbridgensis BASTIAN Buccal cavity 27 to 50 um long, its walls concave; apex of dorsal tooth in 20 30%, of the buccal cavity; body longer than] mm ................ 8

Vulval lips protruding. 9: L = 2.2 mm; a = 31; b =3.7;¢ = 9.2; V = = 58%. ¢ unknown. (Soviet Union [Far East].) ........................

scutarius EROSHENKO Vulval lips simple, not protruding .................................. 9

Apex of dorsal tooth in 30 —33% of buccal cavity; subventral ridges anterior to tooth apex. 9:L = 1.5—1.8 mm;a = 28-34;b = 3.5—4.2; ce = 6.1— —8.4; V = 51-56%. $ unknown. (Hungary, South Africa, Puerto Rico, Argentina.) ................................,......,.............

bellus n. sp. Apex of dorsal tooth further forward; subventral ridges level with tooth apex or, mostly, posterior to that. ...................................... 10

Buccal cavity 45 50 X 18— 22 um, tooth apex in 22 28% ; female tail 250 280 um long. 9: L = 1.6—2.1 mm; a = 26—40; b = 3.4— 4.3; c = 6.4 —8.6; V = 48-55%. d: L =1.7-2.2 mm; a = 32—46; b = 39-4]; c = 8.9-10. (Europe: Holland, Federal Republic of Germany, Democratic

Republic of Germany, Switzerland, Austria, Czechoslovakia, Hungary, Po- land, Denmark, England, Ireland, Finland, Spain, France, Yugoslavia, Italy, Soviet Union [Russia, Belorussia, Georgia, Kirghizia, Uzbekistan, Tadzhikistan]; Asia: Mongolia, Nepal, Japan, Sumatra; Africa: Ivory Coast, Ghana, Mauritius, Uganda, Zaire, Kenya, South Africa; Americas: Canada, United States [Hawaii], Mexico, Columbia, Venezuela, Peru; Australia.) truncatus BASTIAN Buccal cavity 27—31X 13—16 um, tooth apex in 19 23%; female tail 94 160 um long. 9:L = 1.2—2.0mm;a = 19-37;b = 4—5;c = 8-12; V = 46-59%. §: L = 1.7-2.0 mm; a = 26-32; b = 4.3— 4.9; c = 11— —26. (Hungary, Great Britain, Italy, Soviet Union [Russia, Kirghizia], India, Nigeria, Mauritius, South Africa, Mexico, St. Lucia.) ................ aquaticus COETZEE

Mononchus bellus n. sp. (Figs. 1 A— D and 2 A)

Specimens from Puerto Rico, 9: L = 1.58-1.61 mm; a = 29—34; b = = 3.5-4.0;¢ = 6.1— 6.8; V = 54—56% ; © = 7.8—8.2.

Specimens from Argentina, 9: L = 1.54—1.62 mm; a = 30—31; b —4.0;¢ = 6.8-7.0; V = 51-53%: © = 6.7.

Specimens from Hungarv, 9: L = 1.60 —1.79 mm; a = 28—30; b = 4.0 —4.2;¢ = 6.8 8.4: V = 53—54% : © = 6—8.


Body slender, 50 63 um wide. Cuticle smooth, very thin, 1.5—2 um. Head not set off, 24—26 um wide, lips and papillae moderately protruding. Body at posterior end of oesophagus 1.9 2.2 times as wide as head. Amphids caliciform, level with the beginning of stoma or somewhat posterior to it but alwavs well before the dorsal tooth.

Buccal cavity elongated-oval, 40 —47X18—21 um, with nearly parallel walls, about 1/10 of oesophagus length. Dorsal tooth strong with apex lving in 30—33% of the mouth cavity. Subventral ridges fine but distinct, anterior to tooth apex. Oesophagus cylindrical, 380 430 um long, mostly somewhat shorter than the distance between the posterior oesophagus end and the vulva. Oeso- phago-intestinal junction not tuberculate. Intestine with large penta- or hexa- gonal cells and thick intima. Rectum about as long as anal body diameter. In the intestine small nematodes incorporated in toto may be often observed.

Vulval lips small, cuticularized. Vagina 1/3 as long as corresponding body diameter. Gonads paired; the anterior of them 2.5—2.8 times, the posterior 2.8—3.2 times as long as body diameter. Distance between vulva and anus 1.7 2.6 times as long as tail. Egg smooth-shelled, 74 82 x 48 50 um.

Tail 220—258 um long, 6—8.2 times as long as anal body diameter, nearly cylindrical, 6— 6.5 wm wide in its thinnest part and 8 um wide at the terminus. Caudal glands well developed, spinneret terminal. Tail, just before its posterior end, with two very small papillae.

Male unknown.

Brief characteristics: A medium-sized Mononchus species with a large buccal cavity, tooth apex situated comparatively far from the beginning of stoma, ventral ridges lving before tooth apex, and with long tail.



om San Juan, Puerto Rico ; C— D: female tails (400)


fr )

MEN (1000 x

Tt Ag ne Se oO => ot On u ® eS AR ON SE 3 £ S à fe] &


1 of a speci

10r ena

. Mononchus bellus n. sp. A

B: anter:

Figs. 1 A-D (1000x);


(idi Nef MIN


Figs, 2 A—C. Anterior ends of three closely related species of Mononchus. A: M. bellus n. sp. from San Juan, Puerto Rico (1000); B: M. truncatus Bastian, 1865 from the Lake Chungara, Chile

M, aquaticus COETZEE, 1968 from Poroszló, Hungary (1000 x)


(1000 x); C:

Holotype: © on the slide No. Ca 48 in the collection of the author. |

Type locality: San Juan in Puerto Rico, detritus from a rivulet, June 1979.

This new species is so closely related to Mononchus truncatus BASTIAN, 1865 and M. aquaticus COETZEE, 1968 that they three form a definite group with- | in the genus. They can ke separated each from the other by the position of the apex of dorsal tooth and the level of subventral transverse ribs in the buccal cavity. Mononchus bellus n. sp. is characterized among them in having the most posterior position of the tooth apex : in 30 33%, of mouth cavity (in 22 28% at truncatus and in 19—23% at aquaticus); at the same time, the subventral ribs are always situated somewhat before this apex. Besides, M. bellus can be distin- | guished by the much larger buccal cavity from M. aquaticus (40 —47x18— 21 um versus 27—31X 13—16 um). .

I have further specimens of M. bellus in my collection: Ezeiza, Prov. Buenos Aires in Argentina, algae from a pool, December 1961; Gyöngyössolymos in Hungary, Tarna Creek, mosses from the water, June 1975. It must be noted that also the specimens described by COETZEE as “M. truncatus” from South Africa (1968, p. 74, Fig. 5 A B) probably belong to M. bellus. The species is distributed according to recent knowledge in Europe (Hungary), Africa (Union of South Africa), Central and South America (Puerto Rico, Argentina).

Genus Prionchulus (Corg, 1916) Wu & HoerpLı, 1929

Mononchidae, Prionchulinae. Length of body varving between 1.1 and 4.0 mm. Buccal cavity 1.5—2 times as long as wide, barrel shaped. Dorsal tooth large, in anterior third of the mouth cavity, with apex directed forward; opposed by two longitudinal ribs armed with saw-like denticles, 8-20 on each. Oeso- phago-intestinal junction non-tuberculate. Female gonads paired, vulva post- equatorial. Males known for most species; preanal supplementary organs 16 30 in number. Tails of both sexes similar, conoid, arcuate, without caudal glands and terminal opening.

Terrestrial] nematodes, predominantly in mosses; predators.

Type-species: Oncholaimus muscorum DuJARDIN, 1845 = Prionchulus muscorum (DUJARDIN, 1845) Wu & HoEPPLI, 1929.

Six species may be ordered here:

P. auritus n. sp. P. longus (THORNE, 1929) ANDRÁSSY, 1958 Syn. Mononchus longus THORNE, 1929 Mononchus (Prionchulus) longus THORNE, 1929 (GooDEY, 1951)

P. muscorum (DuJARDIN, 1845) Wu & HOEPPLI, 1929

Syn. Oncholaimus muscorum DUJARDIN, 1845 Mononchus muscorum (DUJARDIN, 1845) BASTIAN, 1865 Mononchus (Prionchulus) muscorum (DUJARDIN, 1845) BASTIAN, 1865 (Coss, 1916) Mononchus bastiani DE Man, 1876 Mononchus ctenodentatus Tysowskı, 1915 Prionchulus medius EROSHENKO, 1975


x punctatus (COBB, 1917) CLARK, 1960 Syn. Mononchus (Prionchulus) punctatus CoBB, 1917 Mononchus papillatus apud BRAKENHOFF, 1913 P. spectabilis (DITLEVSEN, 1912) ANDRÁSSY, 1958 Syn. Mononchus spectabilis DITLEVSEN, 1912 Mononchus (Prionchulus) spectabilis DITLEVSEN, 1912 (Cops, 1916) P. vescus EROSHENKO, 1975

| The genus Prionchulus is distributed in every continent except the Antarctic;

| 4 species occur in Europe, 4 in Asia, 1 in Africa, 3 in North America, 1 in South America and 1 in Australia. The most frequent species is P. muscorum having been reported from 28 countries or states. It is followed by P. punctatus occur- .

“ring in 10 countries, Three of the six species are known from a single country.


Prionchulus longus and P. spectabilis. The female genital organ of these

species is somewhat atypical. While in the other species the gonads are short, the oviducts join immediately to the uterus, there is no spermatheca, and the ovaries are at least half as long as the corresponding branch of the gonad (Type I), in both species mentioned above the gonads are long, the oviducts join by sphincters to the uterus, there are well-developed spermathecae, and “the cvaries areshorter than half the length of the corresponding branch of the gonads (Type II). Prionchulus longus and spectabilis are very closely related, perhaps identical species.

Prionchulus medius. I propose P. medius EROSHENKO, 1975 to be a new bynonym of P. muscorum. After the description and figures P. medius cannot se separated from the type species of the genus.

Prionchulus thiocrenobius, Pax and Soös (1943) described from sulphur springs in Germany a species under the name Mononchus (Prionchulus) thiocre- nobius which I transferred (1958) to the genus Prionchulus: P. thiocrenobius (Pax & Soós, 1943) ANDRÁSSY, 1958. The subsequent authors, MULVEY as well (1967), accepted this proposition. My recent opinion is, however, that thiocreno- bius is not a true Prionchulus. Owing to the following characteristics it differs from every species of the genus: 1) the subventral denticles are exceedingly small and arranged in a special way: they are grouped in two very short rows and situated far forward ; 2) the tail is not of the usual conical, ventrally curved type but elongated and provided with caudal glands and spinneret; 3) the vulva is situated more anteriorly (47%) than in the “true” Prionchulus species (54 —69%). On the ground of these “aberrant peculiarities” I prefer to take out thiocrenobius from the genus Prionchulus and regard it as a “species incertae sedis”. It seems not quite impossible that the species of Pax and Soós is conge- neric either with the species of Mononchus or with those of Paramononchus.

Key to the species of Prionchulus

1 Female gonads of type II: long, with elongated uterus, muscular sphincter

between oviduct and uterus, separate spermathecae and short ovaries ..... 2 Female gonads of type I: short and stout, with short uterus and compara- tively long ovaries but without sphincter and spermatheca .............. 3

2 Opuscula Zoologica XXI. 17


Tail comparatively longer (e = 14—22), vulva in 61—69% of body length. 9:L = 21-31 mm; a = 24—31; b = 3.8— 4.6; ¢ = 14-22; V = 61 —69%. 8: L=2.0-29 mm; a = 23—27; b =4.1—4.5; c = 20—27. (Italy, Canada, United States [Colorado]. .............................. longus (THORNE)

Tail comparatively shorter (c = 24—31), vulva in 54—57% of body length. 9:L = 2.5-4.0 mm; a = 31-35; b = 4.6-5.0;c = 24-31; V = 54— —51%. g: L = 2.2-4.0 mm; a = 45-47; b = 46-49; c = 35-46. (Federal Republic of Germany, Switzerland, Hungary, Denmark, Greenland, Sweden, Finland.) ..............................,...,.,,..,..,...... spectabilis (DITLEVSEN)


Labial papillae conoid, protruding, the posterior ones especially prominent, ear-like. 9: L = 2.2— 2.4 mm; a = 30—32; b = 4.0-4.2, ¢ = 13-14; V = 59-62%. S unknown. (Sri Lanka.) .....,,....,.........,,..,....

auritus n. sp. Labia] papillae more rounded, never so prominent or ear-like

4 Smaller species, under 1.5 mm; spicules about 60 um long. ©: L = 1.1— —1.3 mm; a = 17—22; b =3.1-3.7; © = 12-15; V = 61-69%. 4:

L = 1.2 mm;a = 18; b = 3.5; ¢ = 16. (Soviet Union [Far East].) ....... vescus EROSHENKO

Larger species, 1.5 to 2.5 mm; spicules 85 —90 um long ................ 5


Egg shell echinulate; tooth apex in 15 20% of buccal cavity. 9: L = = 1.5— 2.2 mm; a = 27--39; b = 3.6-4.8;¢ = 12-18; V = 59-67%. 6: L =2.0—2.4 mm; a = 32—34; b = 3.7— 4.5; ¢ = 20-25. (Holland, Belgium, Federal Republic of Germany, Switzerland, Great Britain, France, Nepal, Canada, United States, Mexico.) ..........,..............,..... punctatus (CoBB)

Egg shell smooth; tooth apex in 24—28% of buccal cavity. ©: L = 1.8—2.5 mm; a = 26-33; b = 3.3-44;c = 10—18; V = 57-67%. &:

L = 2.2 mm; a = 36—37; b = 4.0—4.1; c = 18—20. (Holland, Federal Republic of Germany, Democratic Republic of Germany, Austria, Hungary, Poland, Spain, France, Italy, Yugoslavia, Denmark, Sweden, Canary Is- lands, Egypt, Mauritius, Zaire, Kenia, India, Mongolia, China, Hainan, Soviet Union [Far East], Canada, United States [California, Florida], St. Lucia, Dominica, Brazil, New Zealand.) ..............................

muscorum (DUJARDIN)

Prionchulus auritus n. sp. (Fig. 3 A—D)

Q: L = 2.2—2.4 mm: a = 30-32; b = 40—4.2; c = 13-14; V = 59— —62%,; © = 3.3—4.2.

Body strongly bent ventrally. Cuticle smooth, 2.3—3 um thick on mid-body region. Head 43—45 um wide, lips separate, labial papillae conoid and protrud- ing, especially the posterior ones which are ear-like (hence the name “‘auritus’’). Amphid with slit-like opening, level with anterior end of mouth cavity.


female genital organ (210 X) 19



d (100%)

10r en. C—D female tails (400 x


figs. 3 A—D. Prionchulus auritus n. sp. A:


Buccal cavity large, 46 —48X 26—27 um (55—56 wm long from anterior margin of head), its wall moderately thick. Dorsal tooth strong with apex situ- ated in 19 20% of buccal cavity (9—10 um from beginning of the latter), oppo- sed by two longitudinal ribs provided with small denticles, 9—10 on each. Oeso- phagus 560—590 um long, heavy muscular, its posterior end not tuberculate. Excretory pore small but visible, 190—200 um from head, or in 33—35% of oesophagus length, respectively. Rectum somewhat shorter than anal body dia- meter. The intestine was empty in every animal.

Vulva with small, 6—7 um long cuticularized knobs. Vagina about 2/5 as long as corresponding body width. Female genital organ paired, comparatively short (Type I); anterior gonad 3.4 4.6 times as long as body diameter, 11— 13% of body length, posterior gonad 3.7 5.2 times as long as body diameter, 12—14% of body length. There were no eggs in the uterus.

Distance between vulva and anus 4—4.6 times as long as tail. This latter 160—180 um, 3.3—4.2 times anal body diameter, strongly curved ventrally with finely rounded tip.

Male unknown.

Brief characteristics: Body of medium size, labial papillae strong, ear-like, mouth cavity large, subventral denticles 9—12 in each row, excretory pore conspicuous, gonads short, tail strongly bent.

Holotype: © on the slide No. A 9608 in the collection of the author.

Type locality: Sri Lanka, Kandy, Nuwara Eliya, mosses from trunk in a rain forest, July 1968, leg. J. BALOGH & I. LOKSA.

Prionchulus auritus n. sp. resembles P. spectabilis (DirLevsen, 1912) ANDRASSY, 1958 in shape and strong development of the labial papillae. It can be distinguished from the latter by the shorter body (spectabilis 2,5—4.0 mm long), the short female genital apparatus (in spectabilis the gonads are long, of type IL), and the comparatively longer and not so sharply pointed tail.

MEYL (1955) described a male specimen under the name Mononchus (Prion- chulus) spectabilis from the German shores which was, however, much shorter than the typical spectabilis and its spicules were also smaller, only half as long as those of spectabilis. CLARK (1960) regarded this nematode as a species inqui- renda. Notwithstanding it is possible that MEYL’s species is conspecific with Prionchulus auritus n. sp. (¢: L = 1.5 mm; a = 21; b = 3.8; c = 24; spicules = 68 um; supplements 25 in number.)



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