Two New Marine Nematodes of Subgenus Quadricoma (Desmoscolecida: Desmoscolecidae: Tricoma) from...
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Two New Marine Nematodes of Subgenus Quadricoma (De smoscolecida: Desmoscolecidae: Tricoma) from Korea Hyung Wook Lim, Ji Min Lee and Cheon Young Chang Department of Biology College of Natural Sciences, Daegu University, Gyeongsan, 712-714 Korea ABSTRACT As a provisional result of the faun istic study on the marine nematodes f rom coastal algal beds and sublittora l sands in Juje Is., South Korea, two new species belonging to the subgenus Quadricoma are reported.Tricoma (Quadrico ma) new species 1 resembles most T. (Q). cobbi Steiner in having 37 main rin gs, the inversion style of rings and the similar setal pattern, however, i t differs from by short body and tail region composed of 8 rings. Tricoma (Q uadricoma) new species 2 is similar to T. (Q.) crassicoma Steiner and T. (Q.) crassicomoides Timm in the number of mai n rings, setal pattern, the position of anus, general shape of head, and s hape of somatic setae. However, the p resent species is distinguished from them in the body length and the uniqu e form of papillar cephalic setae INTRODUCTION Desmoscolecida is an unique marine interstitial nematode order in having the concretion rings and so matic setae. It currently comprises 308 species of 2 1 genera in 2 families. The subgenus Quadricoma belon gs to the subfamily Tricominae Lorenzen, 1969, Which the subgenus Quadricoma Filipjev, 1922, is characteri zed by the shape of quadricomoid all main rings with clearly ring of inversed rings, tricomoid setal patt ern without differentiation in shape between the sub dorsal and subventral somatic setae and in the male reproductive system, by having 2 testes and synonym of Neoquadricoma Kreis, 1963 (Type species : N. arctica Kreis, 1963) in Timm, 1970. However, the taxonomic s tudy on the desmoscolecid nematodes was very scanty in the west Pacific, and still entirely lacking in E ast Asia. This presentation deals with the systematic accou nts on them with illustrations, character comparison table, and photomicrographs using scanning electron microscope or differential interference contrast mic roscope. MATERIALS AND METHODS Materials were collected from seacoast of Juju Is., South Korea in 9 June 20 01 and 19. Nov. 2004 . Samplings were made by gathering sublittoral bottom sands into polyethylene vinyl bag by skin divings, or by scraping the various particula te substrates on algal mats at rocky shore. Nematodes were filtered through nylon net (64 μm in pore diameter) after freshwater rinsing for less than a minute for osmotic shock (Kristensen, 1989), and then fixed with 5 % formalin or 95% ethyl-a lcohol. Specimens were mounted in glycerine on H-S slide (Shirayama et al., 1993), a modification of Cobb slide, after placing in a solution of 5% glycerin in distill ed water for 1-2 days, and observed under a differential interference contrast (D IC) microscope (Olympus BX-51) equipped with Nomarski optics. After examination, slides were sealed with nail polish. All drawings were provided using a camera lu cida. Preparation for scanning electron microscopy were achieved with the formalin- fixed specimens. After an ultrasonic treatment (10 - 30 sec) to remove detritus a ttached to the body, the nematode specimens were prefixed overnight at 4℃ in a 2. 5% buffered glutaraldehyde in 0.1M phosphate buffer (pH 7.4), followed by postfix ation with 1% cold osmium tetraoxide in the same buffer for 1.5-2 hr. After dehyd ration through a graded ethanol series (20%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 1 00%) for 30 minutes each and t-Butyl alcohol for 1 hour, the material was freezin g dried, and coated with platinum-palladium in a high evaporator, and then exami ned in a Hitachi S-4300 operated at 15KV. . Type material. Holotype: female (DB6002-04-1), subtida l sands, Jeju Is., Seongsanpo, 9 June 2001 (C. Y. Chan g and J. M. Lee). Paratype: female, collection data sa me as for holotype. Diagnosis. female with 37 main rings without interzone s; head very wide and short, with truncated anterior m argin; amphidial fovea faint, broadly elliptical, loca ted at posterior half of head; cephalic seta stout, ne arly as long as head width; setal pattern with 6 (or 7) pairs of subdorsal and 10 pairs of subventral seta e; somatic setae simple with blunt end; tail composed of 8 rings; termainal ring a little longer than width, with very short spinneret. Holotype female. Body stout, 385 ㎛ long, pale yellow, composed of 37 main rings with thickened cuticle, with out interzones. Broader posteriorly (most wide at midd le ring), then norrowing posteriorly (tapered towards both extremities). Head short and very wide (about 1.6 times wider than long), with truncated anterior margin; amphidial fovea faint, broadly elliptical, located at posterior half o f head. Cephalic setae stout, nearly as long as head w idth, nearly same in length each other. Stoma narrow. Amphidial fovea faint, broadly elliptical, located bet ween cephalic setae. Setal pattern with 6 (or 7) pairs of subdorsal and 1 0 pairs of subventral setae, as follows: Subdorsal: right 5, 10, 16, 20, 25, 31 = 6 left 5, 10, 20, 25, 31, 35, 36 = 7 Subventral: right 4, 7, 10, 13, 16, 20, 24, 28, 32, 3 6 = 10 left 4, 7, 10, 13, 17, 20, 24, 29, 32, 36 = 10 All somatic setae simple and gently curved with blunt and open tip; lengths of setae a little longer (13-14 ㎛ long) on midlle rings, while a little shorter on bo th extremities (10-12 ㎛ long). Ocelli apparent, and rather big, situated at 7th rin g. Pharynx extending upto 6th ring. Vulva opened betwe en ring 16 and 17. Anus located at 29th ring. Tail region with 8 rings; termainal ring cylindrica l, a little constricted at ventral distal third; a lit tle longer than width; with very short and naked spinn eret, with its end trauncated. Measurements. Holotype female (subtidal sands, Jeju I s., Seongsanpo, 9 June 2001, leg. C. Y. Chang and J. M. Lee): L = 385 ㎛ ; hd = 12 × 7 ㎛ ; cs = 13 ㎛ ; subdorsa l setae left 12, 12, 14, 14, 12, 10, 10; right 12, 12, 13, 14, 14, 12 ㎛ , subventral setae left 12, 12, 13, 1 3, 13, 13, 13, 12, 12, 12; right 12, 12, 13, 13, 13, 1 3, 13, 12, 12, 12 ㎛ ; mbd = 49 ㎛ ; (mbd) = 40 ㎛ ; spinneret = 3 ㎛ ; t = 7 5 ㎛ ; tmr = 12 ㎛ ; tmrw = 11 ㎛ ; oes = 51 ㎛ ; V = 44. Habitat. Specimens were occurred from the subtidal sa nds at Seongsanpo, Jeju Is., Korea. Remarks. This species is most allied with T. (Q). cobbi (Steiner, 1916) from Gold Coast, West Africa (Steine r, 1916), Italy (Timm, 1970) and Australia (Decraeme r, 1978) in having 37 main rings, the inversion style of rings and the similar setal pattern. However, the present new species differs from it by short body (38 5 ㎛ long against, 450-745 ㎛ in T. cobbi), the ring nu mber composing tail region (8 rings against 5-6 rings in T. cobbi), the position of ocelli (on 7th ring, agai nst 8th ring in T. cobbi), and very wide head (1.6 time s wider, against as long as wide in T. cobbi). The char acter comparison among the present new species and th e two related congeneric species above is shown as Ta ble 1. Table 1. Character comparison among three related spe cies with 37-40 main rings in the subgenus Quadricoma SYSTEMATIC ACCOUNTS Order Desmoscolecida Filipjev, 1929 Family Desmoscolecidae Shipley, 1896 Genus Tricoma Cobb, 1893 Subgenus Quadricoma Filipjev, 1922 1. Tricoma (Quadricoma) new species 1 (Figs. 1, 2) Korea. Remarks. seven species with 44 main rings and round h ead have been currently recorded: T. (Q.) crassicoma (S teiner, 1916) from West Africa and California (Steine r, 1916; Timm, 1970) and T. (Q.) crassicomoides Timm, 19 70 from California and Woods Hole (Timm, 1970). The c haracter comparison among the present new species and the two related congeneric species above is shown as Table 2. They share the characters of ring numbers, setal patt ern, the position of anus, general shape of head, and shape of somatic setae. However, the present new spec ies differs from the former by the big body (710 ㎛ lo ng against 475-600 ㎛ long in T. crassicoma), the papil lar form of cephalic setae (agains standard form in T. crassicoma), the length of spicule (165 ㎛ vs. 100 ㎛ i n T. crassicoma), the presence of phasmata, small protr usion around lip region (while absent in T. crassicom a), and the minute spinneret (against long and sharp spinneret in T. crassicoma). This new species also diff ers from T. (Q.) crassicomoides by papillar cephalic set ae (against long jointed cephalic setae in T. crassicom oides), the small and round amphideal fovea (against bi g and oval amphideal fovea in T. crassicomoides), the le ngth and shape of spicule (fishing barb and 165 ㎛ lon g vs. filiform and 137 ㎛ long in T. crassicomoides), an d the minute spinneret (against long and sharp spinne ret in T. crassicomoides). Table 2. Character comparison among Tricoma (Q.) n. s p. 2 and its two related congeneric species. Type material. Holotype: Male (DB6002-05-1), algal hol dfast, Jeju Is., Gujwa, 19. Nov. 2004 (H. W. Lim and J. M. Jeon). Paratype: 2 females, collection data same as for holotype. Diagnosis. Male with 44 main rings without interzones; head very wide and relatively long, with truncated ant erior margin; amphidial fovea faint and round, located at nearly middle of head; cephalic setae transformed i nto papillar form (6 ㎛ long); setal pattern with 8 pa irs of subdorsal and 10 pairs of subventral setae; som atic setae simple with sharp and curved tip; spicule v ery long and narrow with distal third curved, ranging from 27th to 37th rings; tail composed of 13 rings; te rmainal ring a little longer than width, with minute s pinneret. Holotype male. Body stout, 710 ㎛ long, pale yellow, c omposed of 44 main rings with thickened cuticle, witho ut interzones. Cuticles covered with plentiful foreign material of various origins (algae or sand, so on). Br oader posteriorly till inversion around 29th or 30th r ing), then norrowing posteriorly (tapered towards both extremities). Head very wide (about 1.6 times wider than long) and relatively long compared with other related congene r's, with truncated anterior margin. Amphidial fovea f aint and round, located at nearly middle of head (slig htly posteriorly). Lip region surrounded with small pa pillary protrusions. Cephalic setae transformed into p apillar or conical shape with blunt tip (6 ㎛ long). Ocelli small, oval, dark yellow, situated at 8th - 9 th rings. Setal pattern with 8 pairs of subdorsal and 10 pairs of subventral setae, as follows: Subdorsal: right 3, 7, 10, 14, 18, 22, 28, 40, = 8 left 3, 7, 10, 14, 18, 22, 28, 40, = 8 Subventral: right 3, 5, 8, 11, 14, 17, 20, 23, 27, 41 = 10 left 2, 5, 8, 11, 14, 17, 20, 2 3, 27, 41 = 10 Somatic setae simple with sharp and curved tip; seta e longest (25 ㎛ long) on 14th - 28th rings, short (17- 22 ㎛ long) on 2nd - 11th rings. Spicule very long and narrow with distal third curve d, ranging from 27th to 37th rings. Tail composed of 13 rings, abruptly narrowed posteri 2. Tricoma (Quadricoma) new species 2 (Figs. 3, 4) Decraemer, W., 1977. The genus Quadricoma Filipjev, 1922 w ith a redescription of Q. cobbi (Steiner, 1916), Q. crassicomoides Timm, 1970 and Q. loricata Filipje v, 1922 (Nematoda: Desmoscolecida). Cah. Biol. Mar., 19: 63-89. Decraemer, W., 1998. On the deep-sea desmoscolecid fauna of the flat of Cap Vert (Nematoda: Desmoscolecida). Bull. Inst. R. Sci. Nat. Belgique Biol., 68: 5-22. Freudenhammer, I., 1975. Desmoscolecida aus der Iberische n Tiefsee, zuglich eine Revision dieser Nematoden-Or dnung. Meteor. Forsch., 20: 1-65. Kreis, H. A., 1963. Marine Nematoda. Zool. Ice., 2(14): 1 -68. Kristensen, R. M., 1989. Marine Tardigrada from the south eastern United States coastal waters I. Paradoxipus orze liscoides n. gen., n. sp. (Arthrotardigrada: Halechi niscidae). Trans. Am. Microsc. Soc., 108: 262-28 2. Shirayama. Y., T. Kaku. and R. P. Higgins, 1993. Double-s lided microscopic observation of meiofauna using an HS-slide. Benth. Res., 44: 41-44. Steiner, G., 1916. Neue und wenig bekannte Nematoden von der Westküste Afrika's. Zool. Anz., 47: 322-351. REFERENCES Tricoma (Q.) n. sp. 2 T. (Q.) crassicoma Steine r T. (Q.) crassicomoides Ti mm Body length 710 ㎛ 475 - 645 ㎛ 680 - 695 ㎛ Main rings 44 44 44 Cephalic setae very short and thick, unique very thick joint Amphid small round, thin small round thick Interzone absent absent absent Setal pat tern sd = 8 sd = 9 sd = 8 - 9 (pairs) sv = 10 sv = 11 - 12 sv = 12 Nerve ring between 3rd and 4th rings between 4rd and 5th rings Anus 36 - 37 36 - 37 or 37 - 38 36 - 37 Spicule narrow, 165 ㎛ narrow, 100 - 107 ㎛ wiry, 137 ㎛ Spinneret 11 ㎛ 32 ㎛ 35 - 38 ㎛ Phasmata small, round, on tail spike not observed round, on tail spike T. (Q.) n. sp. 1 T. (Q.) brevichaeta Freu denhammer T. (Q.) cobbi Steiner Body length 385 ㎛ 660 ㎛ 525-745 ㎛ Main rings 37 38 37 Head Very wide round Little wide Cephalic setae Stout, thick short, thick thick, pedunculate, jointed, , hook-shaped, Amphid oval, large round. faint Small nearly covered whole head Ocelli lo cation at 7th ring at 7th ring between 7th-8th rings inversion ring 27 27 Setal pat tern 6 6 7 10 8 11-12 Tail rings 8 rings 6 rings 5 or 6 rings Nerve ring between 5th and 6th ring between 4th and 5th ring Anus location 29th 32th 32th Spinneret short (9 ㎛ ), truncated end short (10 ㎛ ), truncated end Short (7.5 ㎛ ), truncated end Fig. 4. Tricoma (Quadricoma) new speci es 2: A, Habitus, lateral; B, Head re gion, lateral; C and D, Amphid and mo uth part, frontal; E, Somatic setae, lateral; F, Tail region, lateral. A B C D E F A B C D Fig. 2. Tricoma (Quadricoma) new speci es 1: A, Head region, lateral; B, Oce lli and oes, lateral; C, Reproductive region, lateral D, Tail region, later al. Scale bars = 30 ㎛ (A, B, C, D). Fig. 1. Tricoma (Quadricoma) new species 1. h abitus, lateral. Scale bar = 50 ㎛. Fig. 3. Tricoma (Quadricoma) new species 2. h abitus, lateral. Scale bar = 50 ㎛.
Transcript of Two New Marine Nematodes of Subgenus Quadricoma (Desmoscolecida: Desmoscolecidae: Tricoma) from...
Two New Marine Nematodes of Subgenus Quadricoma (Desmoscolecida: Desmoscolecidae: Tricoma) from Korea
Hyung Wook Lim, Ji Min Lee and Cheon Young ChangDepartment of Biology College of Natural Sciences, Daegu University, Gyeongsan, 712-714 Korea
ABSTRACT As a provisional result of the faunistic study on the marine nematodes from coastal algal beds and sublittoral sands in Juje Is., South Korea, two new species belonging to the subgenus Quadricoma are reported.Tricoma (Quadricoma) new species 1 resembles most T. (Q). cobbi Steiner in having 37 main rings, the inversion style of rings and the similar setal pattern, however, it differs from by short body and tail region composed of 8 rings. Tricoma (Quadricoma) new species 2 is similar to T. (Q.) crassicoma Steiner and T. (Q.) crassicomoides Timm in the number of main rings, setal pattern, the position of anus, general shape of head, and shape of somatic setae. However, the present species is distinguished from them in the body length and the unique form of papillar cephalic setae
INTRODUCTION Desmoscolecida is an unique marine interstitial nematode order in having the concretion rings and somatic setae. It currently comprises 308 species of 21 genera in 2 families. The subgenus Quadricoma belongs to the subfamily Tricominae Lorenzen, 1969, Which the subgenus Quadricoma Filipjev, 1922, is characterized by the shape of quadricomoid all main rings with clearly ring of inversed rings, tricomoid setal pattern without differentiation in shape between the subdorsal and subventral somatic setae and in the male reproductive system, by having 2 testes and synonym of Neoquadricoma Kreis, 1963 (Type species : N. arctica Kreis, 1963) in Timm, 1970. However, the taxonomic study on the desmoscolecid nematodes was very scanty in the west Pacific, and still entirely lacking in East Asia. This presentation deals with the systematic accounts on them with illustrations, character comparison table, and photomicrographs using scanning electron microscope or differential interference contrast microscope.
MATERIALS AND METHODS
Materials were collected from seacoast of Juju Is., South Korea in 9 June 2001 and 19. Nov. 2004 . Samplings were made by gathering sublittoral bottom sands into polyethylene vinyl bag by skin divings, or by scraping the various particulate substrates on algal mats at rocky shore. Nematodes were filtered through nylon net (64 μm in pore diameter) after freshwater rinsing for less than a minute for osmotic shock (Kristensen, 1989), and then fixed with 5 % formalin or 95% ethyl-alcohol. Specimens were mounted in glycerine on H-S slide (Shirayama et al., 1993), a modification of Cobb slide, after placing in a solution of 5% glycerin in distilled water for 1-2 days, and observed under a differential interference contrast (DIC) microscope (Olympus BX-51) equipped with Nomarski optics. After examination, slides were sealed with nail polish. All drawings were provided using a camera lucida. Preparation for scanning electron microscopy were achieved with the formalin-fixed specimens. After an ultrasonic treatment (10 - 30 sec) to remove detritus attached to the body, the nematode specimens were prefixed overnight at 4 in a 2.5% buffered glutaraldehyde in 0.1M phosphate buffer (pH 7.4), followed by postfixati℃on with 1% cold osmium tetraoxide in the same buffer for 1.5-2 hr. After dehydration through a graded ethanol series (20%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 100%) for 30 minutes each and t-Butyl alcohol for 1 hour, the material was freezing dried, and coated with platinum-palladium in a high evaporator, and then examined in a Hitachi S-4300 operated at 15KV. .
Type material. Holotype: female (DB6002-04-1), subtidal sands, Jeju Is., Seongsanpo, 9 June 2001 (C. Y. Chang and J. M. Lee). Paratype: female, collection data same as for holotype. Diagnosis. female with 37 main rings without interzones; head very wide and short, with truncated anterior margin; amphidial fovea faint, broadly elliptical, located at posterior half of head; cephalic seta stout, nearly as long as head width; setal pattern with 6 (or 7) pairs of subdorsal and 10 pairs of subventral setae; somatic setae simple with blunt end; tail composed of 8 rings; termainal ring a little longer than width, with very short spinneret. Holotype female. Body stout, 385 ㎛ long, pale yellow, composed of 37 main rings with thickened cuticle, without interzones. Broader posteriorly (most wide at middle ring), then norrowing posteriorly (tapered towards both extremities). Head short and very wide (about 1.6 times wider than long), with truncated anterior margin; amphidial fovea faint, broadly elliptical, located at posterior half of head. Cephalic setae stout, nearly as long as head width, nearly same in length each other. Stoma narrow. Amphidial fovea faint, broadly elliptical, located between cephalic setae. Setal pattern with 6 (or 7) pairs of subdorsal and 10 pairs of subventral setae, as follows: Subdorsal: right 5, 10, 16, 20, 25, 31 = 6 left 5, 10, 20, 25, 31, 35, 36 = 7 Subventral: right 4, 7, 10, 13, 16, 20, 24, 28, 32, 36 = 10
left 4, 7, 10, 13, 17, 20, 24, 29, 32, 36 = 10 All somatic setae simple and gently curved with blunt and open tip; lengths of setae a little longer (13-14 ㎛ long) on midlle rings, while a little shorter on both extremities (10-12 ㎛ long). Ocelli apparent, and rather big, situated at 7th ring. Pharynx extending upto 6th ring. Vulva opened between ring 16 and 17. Anus located at 29th ring. Tail region with 8 rings; termainal ring cylindrical, a little constricted at ventral distal third; a little longer than width; with very short and naked spinneret, with its end trauncated. Measurements. Holotype female (subtidal sands, Jeju Is., Seongsanpo, 9 June 2001, leg. C. Y. Chang and J. M. Lee): L = 385 ㎛ ; hd = 12 × 7 ㎛ ; cs = 13 ㎛ ; subdorsal setae left 12, 12, 14, 14, 12, 10, 10; right 12, 12, 13, 14, 14, 12 ㎛ , subventral setae left 12, 12, 13, 13, 13, 13, 13, 12, 12, 12; right 12, 12, 13, 13, 13, 13, 13, 12, 12, 12
㎛ ; mbd = 49 ㎛ ; (mbd) = 40 ㎛ ; spinneret = 3 ㎛ ; t = 75 ㎛ ; tmr = 12 ㎛ ; tmrw = 11 ㎛ ; oes = 51 ㎛ ; V = 44. Habitat. Specimens were occurred from the subtidal sands at Seongsanpo, Jeju Is., Korea. Remarks. This species is most allied with T. (Q). cobbi (Steiner, 1916) from Gold Coast, West Africa (Steiner, 1916), Italy (Timm, 1970) and Australia (Decraemer, 1978) in having 37 main rings, the inversion style of rings and the similar setal pattern. However, the present new species differs from it by short body (385 ㎛ long against, 450-745 ㎛ in T. cobbi), the ring number composing tail region (8 rings against 5-6 rings in T. cobbi), the position of ocelli (on 7th ring, against 8th ring in T. cobbi), and very wide head (1.6 times wider, against as long as wide in T. cobbi). The character comparison among the present new species and the two related congeneric species above is shown as Table 1.
Table 1. Character comparison among three related species with 37-40 main rings in the subgenus Quadricoma
SYSTEMATIC ACCOUNTS Order Desmoscolecida Filipjev, 1929 Family Desmoscolecidae Shipley, 1896 Genus Tricoma Cobb, 1893 Subgenus Quadricoma Filipjev, 1922
1. Tricoma (Quadricoma) new species 1 (Figs. 1, 2)
Korea. Remarks. seven species with 44 main rings and round head have been currently recorded: T. (Q.) crassicoma (Steiner, 1916) from West Africa and California (Steiner, 1916; Timm, 1970) and T. (Q.) crassicomoides Timm, 1970 from California and Woods Hole (Timm, 1970). The character comparison among the present new species and the two related congeneric species above is shown as Table 2. They share the characters of ring numbers, setal pattern, the position of anus, general shape of head, and shape of somatic setae. However, the present new species differs from the former by the big body (710 ㎛ long against 475-600 ㎛ long in T. crassicoma), the papillar form of cephalic setae (agains standard form in T. crassicoma), the length of spicule (165 ㎛ vs. 100 ㎛ in T. crassicoma), the presence of phasmata, small protrusion around lip region (while absent in T. crassicoma), and the minute spinneret (against long and sharp spinneret in T. crassicoma). This new species also differs from T. (Q.) crassicomoides by papillar cephalic setae (against long jointed cephalic setae in T. crassicomoides), the small and round amphideal fovea (against big and oval amphideal fovea in T. crassicomoides), the length and shape of spicule (fishing barb and 165 ㎛ long vs. filiform and 137 ㎛ long in T. crassicomoides), and the minute spinneret (against long and sharp spinneret in T. crassicomoides).
Table 2. Character comparison among Tricoma (Q.) n. sp. 2 and its two related congeneric species.
Type material. Holotype: Male (DB6002-05-1), algal holdfast, Jeju Is., Gujwa, 19. Nov. 2004 (H. W. Lim and J. M. Jeon). Paratype: 2 females, collection data same as for holotype. Diagnosis. Male with 44 main rings without interzones; head very wide and relatively long, with truncated anterior margin; amphidial fovea faint and round, located at nearly middle of head; cephalic setae transformed into papillar form (6 ㎛ long); setal pattern with 8 pairs of subdorsal and 10 pairs of subventral setae; somatic setae simple with sharp and curved tip; spicule very long and narrow with distal third curved, ranging from 27th to 37th rings; tail composed of 13 rings; termainal ring a little longer than width, with minute spinneret. Holotype male. Body stout, 710 ㎛ long, pale yellow, composed of 44 main rings with thickened cuticle, without interzones. Cuticles covered with plentiful foreign material of various origins (algae or sand, so on). Broader posteriorly till inversion around 29th or 30th ring), then norrowing posteriorly (tapered towards both extremities). Head very wide (about 1.6 times wider than long) and relatively long compared with other related congener's, with truncated anterior margin. Amphidial fovea faint and round, located at nearly middle of head (slightly posteriorly). Lip region surrounded with small papillary protrusions. Cephalic setae transformed into papillar or conical shape with blunt tip (6 ㎛ long). Ocelli small, oval, dark yellow, situated at 8th - 9th rings. Setal pattern with 8 pairs of subdorsal and 10 pairs of subventral setae, as follows: Subdorsal: right 3, 7, 10, 14, 18, 22, 28, 40, = 8 left 3, 7, 10, 14, 18, 22, 28, 40, = 8 Subventral: right 3, 5, 8, 11, 14, 17, 20, 23, 27, 41 = 10 left 2, 5, 8, 11, 14, 17, 20, 23, 27, 41 = 10 Somatic setae simple with sharp and curved tip; setae longest (25 ㎛ long) on 14th - 28th rings, short (17-22 ㎛ long) on 2nd - 11th rings. Spicule very long and narrow with distal third curved, ranging from 27th to 37th rings. Tail composed of 13 rings, abruptly narrowed posteriorly; termainal ring a little longer than width, with minute spinneret. Phasmata located on tail spike.Measurements. Holotype male (algal holdfast, Jeju Is., Kujwa, 19. Nov. 2004, leg. H. W. Lim and J. M. Jeon: L = 710 ㎛ ; hd = 31 × 19 ㎛ ; cs = 6 ㎛ ; subdorsal setae 17, 17, 25, 25, 25, 25, 25, 22 ㎛ , subventral setae left 17, 17, 22, 25, 25, 25, 25, 25, 25, 21 ㎛ ; mbd = 92 ㎛ ; (mbd) = 87 ㎛ ; spinneret = 11 ㎛ ; t = 112 ㎛ ; tmr = 16 ㎛ ; tmrw = 11 ㎛ ; oes = 83 ㎛ ; spicule = 165 ㎛ . Habitat. Specimens were occurred from the algal holdfast at Gujwa, Jeju Is.,
2. Tricoma (Quadricoma) new species 2 (Figs. 3, 4)
Decraemer, W., 1977. The genus Quadricoma Filipjev, 1922 with a redescription of Q. cobbi (Steiner, 1916), Q. crassicomoides Timm, 1970 and Q. loricata Filipjev, 1922 (Nematoda: Desmoscolecida). Cah. Biol. Mar., 19: 63-89.
Decraemer, W., 1998. On the deep-sea desmoscolecid fauna of the flat of Cap Vert (Nematoda: Desmoscolecida). Bull. Inst. R. Sci. Nat. Belgique Biol., 68: 5-22.
Freudenhammer, I., 1975. Desmoscolecida aus der Iberischen Tiefsee, zuglich eine Revision dieser Nematoden-Ordnung. Meteor. Forsch., 20: 1-65.
Kreis, H. A., 1963. Marine Nematoda. Zool. Ice., 2(14): 1-68. Kristensen, R. M., 1989. Marine Tardigrada from the southeastern United St
ates coastal waters I. Paradoxipus orzeliscoides n. gen., n. sp. (Arthrotardigrada: Halechiniscidae). Trans. Am. Microsc. Soc., 108:
262-282. Shirayama. Y., T. Kaku. and R. P. Higgins, 1993. Double-slided microscopic
observation of meiofauna using an HS-slide. Benth. Res., 44: 41-44.
Steiner, G., 1916. Neue und wenig bekannte Nematoden von der Westküste Afrika's. Zool. Anz., 47: 322-351.
Timm, R. W., 1970. A revision of the nematode order Desmoscolecida Filipjev, 1922. Univ. Calif. Publi. Zool., 93: 20-21.
REFERENCES
Tricoma (Q.) n. sp. 2 T. (Q.) crassicoma Steiner T. (Q.) crassicomoides Timm
Body length
710 ㎛ 475 - 645 ㎛ 680 - 695 ㎛
Main rings 44 44 44
Cephalic setae
very short and thick, unique very thick joint
Amphid small round, thin small round thick
Interzone absent absent absent
Setal pattern
sd = 8 sd = 9 sd = 8 - 9
(pairs) sv = 10 sv = 11 - 12 sv = 12
Nerve ring between 3rd and 4th rings between 4rd and 5th rings
Anus 36 - 37 36 - 37 or 37 - 38 36 - 37
Spicule narrow, 165 ㎛ narrow, 100 - 107 ㎛ wiry, 137 ㎛
Spinneret 11 ㎛ 32 ㎛ 35 - 38 ㎛
Phasmata small, round, on tail spike not observed round, on tail spike
T. (Q.) n. sp. 1T. (Q.) brevichaeta Freudenh
ammerT. (Q.) cobbi Steiner
Body length
385 ㎛ 660 ㎛ 525-745 ㎛
Main rings 37 38 37
Head Very wide round Little wide
Cephalic setae
Stout, thick short, thickthick, pedunculate,
jointed, , hook-shaped,
Amphidoval, large round.
faintSmall nearly covered whole head
Ocelli location
at 7th ring at 7th ring between 7th-8th rings
inversion ring
27 27
Setal pattern
6 6 7
10 8 11-12
Tail rings 8 rings 6 rings 5 or 6 rings
Nerve ring between 5th and 6th ringbetween 4th and 5th ring
Anus location
29th 32th 32th
Spinneret short (9 ㎛ ), truncated end short (10 ㎛ ), truncated end Short (7.5 ㎛ ), truncated end
Fig. 4. Tricoma (Quadricoma) new species 2: A, Habitus, lateral; B, Head region, lateral; C and D, Amphid and mouth part, frontal; E, Somatic setae, lateral; F, Tail region, lateral.
A B
C D
E F
A B
C D
Fig. 2. Tricoma (Quadricoma) new species 1: A, Head region, lateral; B, Ocelli and oes, lateral; C, Reproductive region, lateral D, Tail region, lateral. Scale bars = 30 ㎛ (A, B, C, D).
Fig. 1. Tricoma (Quadricoma) new species 1. habitus, lateral. Scale bar = 50 ㎛ .
Fig. 3. Tricoma (Quadricoma) new species 2. habitus, lateral. Scale bar = 50 ㎛ .
