Figure 1:
Molecular phylogeny of Pristionchus species. The phylogeny shows a maximum likelihood tree that was inferred from a concatenated alignments of more than 1200 orthologous gene clusters. Branch lengths reflect the estimated number of amino acid substitutions per site and branch labels show bootstrap support values (100 pseudoreplicates). The accession numbers next to the species names denote the Run accession in the European nucleotide Archive, where the raw RNA-seq reads were deposited.
Figure 2:
Pristionchus hangukensis n. sp. A: Male; B: Female; C: Anterior region; D: Relative position of secretory-excretory pore, deirid and one of lateral glands; E: Surface of anterior end of adult male in right lateral view showing the relative position of labial sensilla, cephalic sensilla and amphid; E, F: Male stenostomatous form in left (E) and right (F) lateral views; G, H: Male eurystomatous form in left (G) and right (H) lateral views. Tooth and denticules are separately drawn under whole head region in E–H.
Figure 3:
Pristionchus hangukensis n. sp. A, B: Whole male tail in right lateral (A) and ventral (B) views; C, D: Close-up of posterior four pairs of genital papillae and phasmid in right lateral (C) and ventral (D) views; E, F: Spicule and gubernaculum of two different individuals in right lateral view; G: Ventral view of female vulval region; H, I: Anal region of female in left lateral (H) and ventral (I) views.
Figure 4:
Stomatal region of Pristionchus hangukensis n. sp. showing variation among individuals. A: Surface and stoma of male in left lateral view in five different focal planes showing the relative position of labial sensilla, cephalic sensilla, amphid, left subventral ridge and dorsal tooth; B, C: Male (B) and female (C) stenostomatous form in right lateral views in two different focal planes; D, E: Female eurystomatous form in left (D) and right (E) lateral views in two different focal planes. Abbreviations are as follows: am = amphid; cs = cephalic sensilla; d = dorsal tooth; ls = labial sensilla; lsv = left subventral ridge; rsv = right subventral ridge or tooth.
Figure 5:
Male tail characters of Pristionchus hangukensis n. sp. A: Right lateral view of whole tail in three different focal planes; B: Left subventral view of whole tail; C: Spicule and gubernaculum in right lateral view in three focal planes. Abbreviations are as follows: ad, pd and v + number = genital papillae, where ending with ‘d’ suggests that the papillae are directed laterally or subdorsally; ph = phasmid; vs = ventral single papilla.
Table 1:
Morphological measurements of the two new species.
| Character | Pristionchus coreanus n.sp. RS6268 | Pristionchus hangukensis n.sp. RS6291 | ||
|---|---|---|---|---|
| stenostomatous male | stenostomatous female | stenostomatous male | stenostomatous female | |
| n | 10 | 10 | 10 | 10 |
| L | 1002 ± 94.3 (872 – 1158) | 1448 ± 126.0 (1312 – 1661) | 928 ± 54.8 (858 – 1001) | 1336 ± 90.2 (1248 – 1542) |
| L’ | 851 ± 93.3 (721 – 1025) | 1211 ± 120.4 (1067 – 1442) | 764 ± 41.0 (685 – 820) | 1078 ± 76.5 (993 – 1249) |
| a | 13 ± 2.2 (9.1 – 16) | 12 ± 1.5 (11 – 16) | 13 ± 1.3 (11 – 16) | 13 ± 0.7 (11 – 14) |
| b | 6.0 ± 0.4 (5.5 – 6.7) | 7.6 ± 0.5 (6.8 – 8.4) | 7.0 ± 0.4 (6.5 – 7.6) | 9.0 ± 0.7 (8.0 – 10.0) |
| c | 6.7 ± 0.9 (5.7 – 8.5) | 6.1 ± 0.5 (5.4 – 7.1) | 5.8 ± 0.4 (5.3 – 6.6) | 5.3 ± 0.5 (4.9 – 6.3) |
| c’ | 3.4 ± 0.5 (2.5 – 4.0) | 4.4 ± 0.6 (3.8 – 5.5) | 4.4 ± 0.5 (3.9 – 5.3) | 6.4 ± 0.6 (5.5 – 7.7) |
| Ant. stoma length (cheilo- + gymnostom) | 5.1 ± 0.8 (4.0 – 6.7) | 5.7 ± 1.4 (4.0 – 7.8) | 6.9 ± 1.1 (5.0 – 9.3) | 7.7 ± 0.7 (6.7 – 9.1) |
| Total stoma length | 11 ± 1.0 (9.3 – 12) | 12 ± 1.1 (11 – 14) | 10 ± 1.1 (8.3 – 11.6) | 13 ± 1.0 (11 – 14) |
| Stoma width | 5.8 ± 0.4 (5.3 – 6.5) | 7.5 ± 0.9 (6.0 – 8.7) | 4.9 ± 0.9 (3.6 – 6.5) | 5.4 ± 0.9 (4.3 – 7.5) |
| Ant. pharynx (pro + metacorpus) | 95 ± 7.6 (83 – 111) | 109 ± 8.2 (99 – 130) | 69 ± 5.6 (63 – 82) | 79 ± 6.0 (72 – 89) |
| Post. pharynx (isthmus + basal bulb) | 67 ± 7.0 (56 – 78) | 77 ± 5.1 (69 – 87) | 57 ± 2.9 (54 – 61) | 61 ± 3.6 (55 – 66) |
| Total pharynx length | 162 ± 13.6 (142 – 183) | 186 ± 12.1 (176 – 217) | 126 ± 7.6 (120 – 143) | 140 ± 7.4 (131 – 152) |
| Ant./total pharynx % | 59 ± 1.7 (57 – 62) | 58 ± 1.5 (56 – 62) | 55 ± 1.6 (52 – 57) | 57 ± 2.2 (54 – 60) |
| Median bulb diameter | 27 ± 2.5 (24 – 32) | 35 ± 2.9 (31 – 40) | 23 ± 1.2 (21 – 24) | 27 ± 2.0 (25 – 31) |
| Terminal bulb diameter | 28 ± 3.9 (22 – 36) | 36 ± 4.9 (31 – 46) | 22 ± 1.1 (20 – 23) | 27 ± 2.3 (24 – 33) |
| Ant. end to cardia | 167 ± 13.2 (151 – 191) | 192 ± 8.8 (185 – 212) | 132 ± 8.4 (123 – 148) | 148 ± 7.5 (139 – 160) |
| Ant. end to S-E pore | 149 ± 15.5 (125 – 170) | 195 ± 15.5 (171 – 214) | 114 ± 11.3 (99 – 139) | 153 ± 12.0 (137 – 172) |
| Ant. end to nerve ring | 118 ± 9.2 (109 – 133) | 136 ± 8.9 (124 – 155) | 97 ± 6.2 (90 – 108) | 111 ± 6.5 (104 – 124) |
| Testis length | 703 ± 83.8 (571 – 827) | - | 630 ± 59.4 (529 – 718) | - |
| Ant. end to vulva distance | - | 691 ± 66.1 (600 – 821) | - | 608 ± 40.2 (563 – 703) |
| Vulva to anus distance | - | 525 ± 60.0 (454 – 628) | - | 473 ± 37.3 (420 – 543) |
| T or V | 70 ± 4.3 (66 – 80) | 48 ± 1.5 (46 – 50) | 68 ± 6.7 (53 – 77) | 46 ± 1.1 (43 – 47) |
| Max. body diameter | 78 ± 19.1 (63 – 127) | 121 ± 16.4 (91 – 141) | 71 ± 5.1 (64 – 81) | 105 ± 8.1 (93 – 115) |
| Cloacal or anal body diameter | 45 ± 5.3 (40 – 54) | 54 ± 5.3 (43 – 63) | 36 ± 2.2 (33 – 39) | 39 ± 3.5 (33 – 45) |
| Tail length | 149 ± 10.8 (129 – 161) | 237 ± 23.7 (208 – 296) | 159 ± 13.9 (132 – 178) | 252 ± 27.0 (204 – 297) |
| Spicule curve | 50 ± 4.3 (40 – 54) | - | 46 ± 2.3 (43 – 50) | - |
| Spicule chord | 42 ± 2.9 (36 – 47) | - | 38 ± 2.6 (35 – 43) | - |
| Gubernaculum length | 18 ± 2.4 (13 – 21) | - | 18 ± 1.6 (16–22) | - |
Figure 6:
Pristionchus coreanus n. sp. A: Male; B: Female; C: Anterior region; D: Relative position of secretory-excretory pore, deirid, and two lateral glands on the lateral field.
Figure 7:
Stomatal region of Pristionchus coreanus n. sp. showing variation among individuals. A: Surface of anterior end of adult male in right lateral view showing the relative position of labial sensilla, cephalic sensilla and amphid; B, C: Male stenostomatous form starved culture in left (B) and right (C) lateral views; D, E: Female stenostomatous form from starved culture in left (D) and right (E) lateral views; F, G: Female stenostomatous form from well-fed culture in left (F) and right (G) lateral views. Tooth and denticules are separately drawn under whole head region in B–G.
Figure 8:
Pristionchus coreanus n. sp. A, B: Whole male tail in right lateral (A) and ventral (B) views; C, D: Close-up of posterior four pairs of genital papillae and phasmid in right lateral (C) and ventral (D) views; E: Spicule and gubernaculum in right lateral view; F: Anterior gonad of mature female in right lateral view; G: Ventral view of female vulval region; H, I: Anal region of female in right lateral (H) and ventral (I) views.
Figure 9:
Stomatal region of stenostomatous form of Pristionchus coreanus n. sp. showing variation among individuals. A: Surface and stoma of male in left lateral view in three different focal planes showing the relative position of labial sensilla, cephalic sensilla and amphid; B: Left lateral view of male from well-fed culture in two different focal planes; C: Right lateral view of male from starved culture in two different focal planes; D: Left lateral view of female from starved culture in two different focal planes; E: Right lateral view of female from starved culture in two different focal planes; F: Left lateral view of female from well-fed culture in two different focal planes; G: Right lateral view of female from well-fed culture in two different focal planes. Abbreviations are as follows: am = amphid; cs = cephalic sensilla; d = dorsal tooth; ls = labial sensilla; lsv = left subventral ridge; rsv = right subventral ridge or tooth.
Figure 10:
Male tail characters of Pristionchus coreanus n. sp. Right lateral view of whole male tail in five different focal planes. Abbreviations are as follows: ad, pd and v + number = genital papillae where ending with ‘d’ suggests that the papillae are directed laterally or subdorsally; ph = phasmid; vs = ventral single papilla.
Supplemental Figure 1:
18S tree for different Pristionchus species. The 18S rRNA sequences for the two new species were aligned together with their best hits from the NCBI database and a maximum likelihood tree was calculated using the phangorn package in R.