Description and Larval Heteromorphism of Hoplolaimus concaudajuvencus, n. sp. (Nematoda: Hoplolaimidae) 1 A. MORGAN GOLDEN AND NORMAN A. MINTON 2 Abstract: Hoplolaimus concaudajuvencus n. sp., of the genus Hoplolaimus Daday, 1905, characterized by larval heteromorphism, is described and illustrated as recovered from ryegrass/bermudagrass golf green turf in Florida. Females and males are closely related to H. galeatus (Cobb, 1913) Thorne, 1935, but have longer stylets with more definitely tulip-shaped stylet knobs which anteriorly tend to close upon the stylet shaft more than in H. galeatus. First and second-stage larvae have a conically-pointed tail unlike any known species of the genus. Subsequent stages, including females, have rounded tails es- sentially similar to other species of the genus and males possess the typical hopolaimid tail and bursa. The first molt was found to occur within the egg. Key Words: Taxonomy, Hoplolaimus concaudaju- vencus n. sp., Morphology, Larval heteromorphism. In November of 1966 a moderately high Hoplolaimus concaudajuvencus, population of Hoplolaimus Daday, 1905 was n. sp. recovered along with other nematodes from Measurements (20 ~ 2, Fig. 1 A, B, a sample of golf green turf, consisting of and Fig. 2 J, K): Length 1.606 mm (1.120- annual ryegrass (Loliurn multiIlorum Lam.) 2.041); a -- 28.6 (23.9-31.9); b = 8.6 (6.3- and "Tifgreen" bermuda grass (Cynodon dac- 11.0); c = 65.1 (49.5-85.9); V = 54.4% tylon [L.] Pers.), from Pensacola, Florida. (50-57); stylet -- 54.9 t~ (50.4-56.6). Examination of the Hoplolaimus specimens HOLOTYPE ( Q ): Length 1.848 mm; a = revealed that the adults, although closely 30.8; b = 9.0; c = 66.0; V = 55%; styler related to H. galeatus (Cobb, 1913 ) Thorne, 54.3 ~; outlet of dorsal esophageal gland 1935, differed from it in certain characters. 5.04 ~; right phasmid 30% of body length; Furthermore, the tail shapes of first and left phasmid 80% of body length; tail second-stage larvae differed from those of its rounded, with 11 annules. other larval stages and females and also DESCRIPTION OF FEMALES: Body cyl- differed from those of any other known hop- indroid, vermiform, tapering slightly at both lolaimid nematodes. ends. Mid-body width averaging 56 ~ (44- This paper presents a description of this 68). Head with massive cephalic framework new species and gives data on certain larval and markedly set off, usually bearing five to stages. The specific name, a Latin compound six annules with the basal one subdivided word, refers to the distinctive conically- into about 36 plate-like blocks. Cuticular pointed tail of the first and second-stage annulation prominent, each annule at mid- larvae. body measuring about 3 /~ or slightly more; sub-cuticular annulation also quite distinct Received for publication 1 October 1969. and twice as numerous as on the cuticle. Lat- 1 Cooperative Investigations, Crops Research Division, eral field about 15 ~ wide (13-19), aerolated, Agricultural Research Service, U. S. Department of Agriculture and the University of Georgia College of with four lines except in extreme anterior Agriculture Experiment Stations, Coastal Plain Station, Tifton. Journal Series Paper No. 603. portion where it narrows to two before end- '-' Nematologists, Crops Research Division, Agricultural ing in vicinity of stylet. Stylet large and Research Service, U. S. Department of Agriculture, Belts- ville, Maryland 20705, and Tifton, Georgia 31794. Appre- strong, with prominent basal knobs appearing ciation is extended for the help of Mrs. Donna Ellington, Research Assistant, in the laboratory of senior author. tulip-shaped and variably dentate anteriorly, 161 162 Journal o/ Nematology, Vol. 2, No. 2, April 1970 ~lii!'~"~~ "..,~, ~.~ r,.,'~R ~ill ,' '--.,,../i.~.","~.. ~ ~::',~~,,.::!~ ~..,~,, I ' , .'. "-:..~..~ • . '~'~ D 0 Hoplolaimus: NEW SPECIES WITH LARVAL HETEROMORPHISM " Golden, Minton 163 Outlet of dorsal esophageal gland 5.18 t~ (6.2-8.8); c = 37.9 (33.5-45.6); stylet (4.48-5.60) from base of stylet. 50 ~ (46.5-53.8); outlet of dorsal esopha- Metacorpus ovate with well-developed, geal gland 5.7 t~ (5.6-6.7); spicules 50 t~ (45- sclerotized valve. Esophageal glands with 56); gubernaculum 26 ~ (23-28). three nuclei. Dorsal gland generally appear- ALLO'rVPE (male) : Length 1.570 mm; ing more prominent and of different texture a -- 29.8; b = 7.0; c = 41.3; stylet 52 e; than sub-ventrals as illustrated (Fig. 1A). outlet of dorsal esophageal gland 6.2 ~; spic- Length of esophagus (from anterior end to ules 55 t~; gubernaculum 27 ~; right phasmid base of esophagus) 187 t~ (138-235). Dis- 24% of body length; left phasmid 79% of tinct nerve ring encircling isthmus just poste- body length from anterior end. rior to metacorpus. Cephalids located in DESCRIPTION OF MALES: Body shape anterior portion as illustrated (Fig. 1A). similar to female. Mid-body width averaging Excretory pore prominent, located at level 54t~ (46-66). Anterior portion essentially of posterior third of esophageal glands. Hem- as in female but head generally more set off izonid large, two annules in length, and and knob-like, as illustrated (Fig. 1D). Cu- located about one to two annules in front of ticular annulation prominent with sub-cutic- excretory pore. Hemizonion quite small, sit- ular annules twice as numerous as on cuticle. uated 6-12 annules behind excretory pore. Lateral field aerolated, with 4 lines averag- Phasmids (scutella) large and conspicuous, ing 12.2 t~ (11.2-14.0) in width. Testis variable in position. Right phasmid in ma- one, outstretched anteriorly. Spicules, guber- jority of specimens located 28% (23-35) of naculum and bursa large and conspicuous, body length from anterior end, but in about appearing generally as illustrated (Fig. 1C). 20% of specimens it was found at 80% (78- Tail as shown, measuring 38 t~ (28-40). 83) of body length. Left phasmid in major- Phasmids (scutella) large and conspicuous; ity of specimens situated at 78% (73-85) of and as in female, variable in position. Right body length while approximately 20% of the phasmid in majority of specimens located at specimens had it at 29% (26-33) of the body 31% (23-42) of body length while about length. 20% had it at 78% (76-80). Left phasmid Vulva a deep and prominent transverse slit situated at 79% (74-83) of body length in near mid-body; epiptygma small, single, and majority of specimens but seen at 31% (28- generally attached anteriorly. Ovaries two, 36) in approximately 20% of the specimens. outstretched (amphidelphic). Spermatheca Measurements (20 second-stage larvae, round to oval, generally with many sperm Fig. 2 A, D, G): Length 0.283 mm (.258- (spermatozoa). Tail rounded, measuring .312);a = 14.4 (10.7-I5.6);b = 2.5 (2.1- 25 t~ (18-33) in length with 10 annules (7- 3.4); c = 8.6 (7.3-10.5); stylet 26.2 ~ (24- 14). Caudalid small and inconspicuous, 28); outlet of dorsal esophageal gland 2.9 located approximately one tail length ante- (2.8-3.4). rior of anus. Body cylindrical, elongate, tapering at Measurements (20 ~ ~, Fig. i C, D, both ends. Anterior portion similar to female and Fig. 2 L, M): Length 1.423 mm (1.118- but much smaller. Head conically rounded 1.608); a = 25.9 (20.0-30.7); b = 7.2 with about five annules and with heavy scle- <-. FI~. I. Hoplolaimus concaudajuvencus, n. sp.: A. ~ Anterior; B. ~ Tail; C. ~ Tail; D. (~ Anterior. 164 Journal o[ Nematology, Vol. 2, No. 2, April 1970 D Hoplolaimus: NEW SPECIES WITH LARVAL HETEROMORPHISM • Golden, Minton 165 rotization. Stylet shape essentially as in measurements and characteristics. Differs female. Body averaging 20 ~ (18-25) in from the most closely related described spe- width; esophagus (from base of esophageal cies, H. galeatus (Cobb, 1913) Thorne, 1935, glands to anterior end) relatively long, being especially by: (i) presence of conically 115 ~ (93-130). Reproductive structure pointed tail in first and second-stage larvae; represented by a gonad primordium of four (ii) longer stylet (averaging 54.9 /, (50.4- cells, probably two germ cells and two epi- 56.6) in females but 43-52 ~ in H. galeatus); thelial cells. Lateral field with four lines, (iii) stylet knobs are more tulip-shaped and 3.2 ~ (2.8-3.4) in width. Phasmids (scu- more dentate anteriorly, and tend to close tella) relatively large, the right one located at upon the stylet shaft more than in H. galeatus. 57% (51-64) of body length and left phas- mid at 88% (85-91). Tail conically pointed, DEVELOPMENT OF LARVAE (Fig. 2 A-I) ending in an acute terminus. (Third-stage AND DISCUSSION larvae have round tail as in female.) Length In the initial turf sample from Pensacola, of tail 33 t~ (27-38). Florida, a small number of Hoplolaimus HOLOTYPE ( 9 ): Collected by Norman larvae in various stages of development were A. Minton at Pensacola, Florida on Novem- observed in addition to the adults. The ber 6, 1966. Slide T-145t United States larger larvae and females were seen to have Department of Agriculture Nematode Collec- a rounded tail similar to that of other species tion, Beltsville, Maryland. of Hoplolaimus. The smaller larvae, how- ALLOTYPE ( 6 ): Slide T-146t. Same ever, possessed tails that tapered markedly to data and collection as holotype. a conical, acute terminus unlike any other PARATYPES ( c~ ~, 9 9, and larvae of known hoplolaim. various stages): United States Department To provide specimens for further study, a of Agriculture Nematode Collection, Belts- culture of this nematode was established on ville, Maryland; and California Nematode the original turf from Pensacola in the green- Survey Collection, Davis. Additional speci- house at Tifton, Georgia. mens from a greenhouse culture to Depart- In subsequent laboratory tests with nem- ment of Nematology, University of California, atodes from this culture, approximately 10 Riverside.