Trischistoma abharensis, Asghari, Ramezan, Eskandari, Ali, Maafi, Zahra Tanha, Zhao, Zeng Qi, Álvarez-Ortega, Sergio & Nadirkhanloo, Majid, 2015
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publication ID |
https://doi.org/ 10.11646/zootaxa.3986.3.5 |
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publication LSID |
lsid:zoobank.org:pub:913BB1FB-1C29-403A-A4A6-738D306DDFFC |
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DOI |
https://doi.org/10.5281/zenodo.5616813 |
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persistent identifier |
https://treatment.plazi.org/id/F9190C3A-3945-FFE3-CCF8-FBD8FB2FFF35 |
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treatment provided by |
Plazi |
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scientific name |
Trischistoma abharensis |
| status |
sp. nov. |
Trischistoma abharensis n. sp.
( Figs 1‒3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )
Measurements. See Table 1 View TABLE 1 .
Material examined. Holotype female and two paratype females deposited in Nematode Collection of the Faculty of Agriculture, University of Zanjan, Zanjan, Iran (slide no, N4–1, N4–2). Two paratype females deposited at the National Nematode Collection, New Zealand ( NNCNZ).
Description. Female (n = 9). Body slender, bent dorsad mainly in the posterior part after heat relaxation ( Fig. 1 View FIGURE 1 E). Cuticle very thin, 1–2 Μm thick, apparently smooth under light microscopy (LM) but fine transverse striations seen with SEM, with sparse somatic setae on the sublateral body. Labial region broadly rounded, slightly offset, 12.3 ± 0.5 (12–13) Μm diameter. SEM and LM micrographs ( Figs 2 View FIGURE 2 A,B; 3A‒C) show: three triangular lips, labial papillae short and conical, outer labial and cephalic setae in two whorls, six longer setae (outer labial) 6.7 ± 0.4 (6.0–7.5) Μm long, 50–58% of head diameter long, more or less arcuate and directed anteriorly, four shorter setae (cephalic setae) 5.2 ± 0.3 (4.5–6) Μm, 38–46% of head diameter long, thinner than the outer labial setae, more or less arcuate. Ventral cervical setae absent but a pair of thin sublateral setae placed at about half (51–59%) the pharynx length ( Fig. 1 View FIGURE 1 C), 144 ± 7.4 (135–153) Μm from anterior end. Amphid small, calyciform, 18.5 ± 0.9 (18– 20) Μm from anterior end. Mouth cavity narrow, dorsal tooth distinct, 17.6 ± 1.1 (16–19) Μm from anterior end of body, subventral tooth not seen or difficult to observe. ( Figs 1 View FIGURE 1 A,B; 2C). Pharynx cylindrical, strongly muscular. Cardia small, disc-like ( Fig. 2 View FIGURE 2 D). No glands between pharynx and intestine observed. Coelomocytes not seen.
Genital tract mono-prodelphic, 332–397 Μm long, reflexed anteriorly, tip not reaching vulva. Distance between posterior end of pharynx and vulva 2.7–3.0 times longer than pharynx. Vulval lips not sclerotized, vagina short, less than one third body diameter and surrounded by muscular tube ( Fig. 2 View FIGURE 2 F). Post-vulval uterine sac absent. Vulvaanus distance 2.6 ± 0.2 (1.9–4.0) tail lengths. Rectum almost as long as anal body diameter ( Fig. 2 View FIGURE 2 G). Tail 74 ± 3.5 (60–87) Μm long, conoid, and dorsally bent, with one pair subdorsal caudal setae ( Fig. 3 View FIGURE 3 G). Three caudal glands, spinneret small.
Male. Not found.
Type habitat and locality. The new species was extracted from the rhizosphere of grapevines, in Abhar, Zanjan province, Iran (GPS coordinates: 36° 6ʹ 22.03" N, 49° 16ʹ 28.65" E). All specimens were collected by the last author during July-August 2013.
Diagnosis and Relationships. Trischistoma abharensis n. sp. is characterised by having females with body length of 1069–1322 Μm; sparse somatic setae on the sublateral body; absence of ventromedian cervical setae; a distinct dorsal tooth directed anteriorly; absence of post-vulval uterine sac (PVS); and a pair of caudal setae on the tail. Males were not found, suggesting that they are either rare or absent.
The species in the genus Trischistoma are divided into two groups with or without a PVS ( Table 2 View TABLE 2 ). Trischistoma abharensis n. sp. belongs to the second group (i. e. without a PVS), containing T. waiotama , T. pellucidum , T. tukorehe and T. gracile .
Trischistoma abharensis n. sp. is morphologically similar to T. gracile , but it can be separated by having slightly longer body length (1069–1322 vs 1000–1100 Μm), more slender body (a = 53.5–62.6 vs 49–53), longer pharynx (240–266 vs 205–216 Μm), the location of the dorsal tooth: (posterior to cephalic setae and 16–19 Μm from the anterior end vs opposite to cephalic setae and 12 Μm from the anterior end), distinct dorsal tooth vs indistinct or minute dorsal tooth, having sparse somatic setae on the body vs absent; and a pair of caudal setae on the tail vs absent.
The new species differs from T. waiotama by having a longer body length (1069–1322 vs 675–908 Μm) and more slender body shape (a = 53.5–62.6 vs 32–41), longer pharynx (240–266 vs 171–198 Μm), posterior position of dorsal tooth (16–19 vs 13–15 Μm from anterior end), tail length (60–87 vs 50–64 Μm), ventral cervical seta (absent vs present), lateral cervical seta (or somatic seta) in the cervical region (present vs absent). It can be separated from T. pellucidum by its longer body length (1069–1322 vs 600–800 Μm) and more slender body (a = 53.5–62.6 vs 36– 43), longer pharynx (240–266 vs 155 Μm), having a distinct dorsal tooth vs a minute dorsal tooth, lateral cervical seta (or somatic seta) in the cervical region (present vs unknown) and tail length (78–87 vs 50–60 Μm). It also differs from T. tukorehe by having a more slender body (a = 53.5–62.6 vs 38.5–47.1), number of dorsal tooth (one vs two), lateral cervical seta (or somatic seta) in the cervical region (present vs absent).
The new species lacks a post-vulval uterine sac and differs from the species possessing this character viz: T. monohystera , T. equatoriale , T. otaika , T. subtilissimum , T. tenuissimum and T. veracruzense .
Etymology. Species epithet refers to the city of Abhar, where the type specimen was collected.
TABLE 1. Morphometric data for Trischistoma abharensis n. sp. and Tripylella intermedia (Bütschli, 1873) Brzeski & Winiszewska-Ślipinska, 1993. All measurements are in Μm and in the form: mean ± s. d. (range).
| Characters | Trischistoma abharensis n. sp. Female | Tripylella intermedia (Bütschli, 1873) Brzeski & Winiszewska-Ślipinska, 1993 Female |
|---|---|---|
| n L | Holotype Paratype - 8 1209 1195 ± 58.6 (1069–1322) | 7 966 ± 40.6 (905–990) |
| L' a b | 1131 1121 ± 57.2 (1009–1236) 57.6 57.5 ± 3.2 (53.5–62.6) 4.6 4.7 ± 0.2 (4.3–5.0) | 966.9 ± 61.1 (881–1067) 23.2 ± 2.0 (21.5–26.0) 4.7 ± 0.3 (4.3–5.1) |
| c c' V | 15.5 16.3 ± 0.8 (14.6–18.3) 4.6 4.4 ± 0.2 (3.5–5.1) 79.7 77.7 ± 0.8 (72.7–81.2) | 7.2 ± 0.2 (6.9–7.6) 4.7 ± 0.3 (4.2–5.2) 50.0 ± 1.7 (48.1–52.6) |
| V' Head Height Head Width | 85.2 82.9 ± 0.8 (76.9–86.4) 2.0 2.0 ± 0.4 (1.5–2.5) 13.0 12.3 ± 0.5 (11.5–13) | 58.2 ± 2.0 (55.9–60.9) 2.9 ± 0.4 (2.5–3.5) 17.5 ± 1.0 (16–19) |
| Dorsal tooth anterior Subventral tooth Nerve ring-anterior | 17.0 17.6 ± 1.1 (16–19) - - 106.0 99.1 ± 4.9 (90–109) | 18.6 ± 0.5 (18–19) 15.0 ± 1.4 (13–16) 95.0 ± 7.0 (87–106) |
| Nerve ring/Pharynx*100 Pharynx Head-Vulva | 40.6 38.9 ± 1.6 (37.3–41.0) 261.0 254.2 ± 3.7 (240–266) 964 930.1 ± 43.7 (800.0–1058.5) | 46.3 ± 2.8 (43.6–48.8) 207.4 ± 9.2 (190–218) 483.1 ± 22.9 (458–514) |
| Body Width (BW) Anal Body Width Vulva-Anus | 21.0 20.8 ± 0.5 (19–22) 17.0 16.7 ± 0.4 (16.0–17.5) 167.0 190.9 ± 16.4 (141–242) | 41.9 ± 4.4 (34–46) 29.1 ± 1.9 (26–31) 348.6 ± 34.1 (297–398) |
| Tail Tail/ABW | 78.0 74 ± 3.5 (60–87) 4.6 4.4 ± 0.2 (3.5–5.1) | 135.1 ± 11.2 (121–155) 4.5 ± 0.4 (4.2–5.0) |
TABLE 2. Comparative morphometrics of Trischistoma species (new species in bold text). All measurements are in Μm and in the range form.
| Species L equatoriale 1400 –1600 | a 38–44 | b 4.9–5.8 | c 15–21 | c ’ 3.2–3.8 | V 81–83 | Cervical seta or setae Females Unknown | Post-vulval sac Present | Spicules - | Supplements - | References Andrássy 2006 |
|---|---|---|---|---|---|---|---|---|---|---|
| gracile 1000 –1100 | 49–53 | 4.9–5.3 | 12–13 | 5.0–5.5 | 76–78 | Unknown | Absent | - | - | Andrássy 1985; Andrássy 2011 |
| monohystera 1400 –1900 | 45–77 | 5.0–6.5 | 12–15 | 5–7 | 75–85 | Unknown | Present | - | - | de Man 1880; Schuurmans Stekhoven 1951 |
| otaika 1215 –1326 | 43.7–48.8 | 4.7–4.8 | 12.8–15.0 | 4.2–4.6 | 73–76 | No | Present | - | - | Zhao, 2011 |
| pellucidum 600–800 | 36–43 | 4.4–4.8 | 11–14 | 3.5–4.0 | 73–84 | Unknown | Absent | - | - | Andrássy 1968 |
| subtilissimum 2900 –3200 | 123–146 | 6.2–7.2 | 12–14 | 12–14 | 73–76 | Unknown | Present | - | - | Andrássy 2011 |
| tenuissimum 4000–4100 | 94–100 | 6.5–6.6 | 16 | 7.6 | 74–75 | Unknown | Present | - | - | Andrássy 2011 |
| triregius 611–846 | 29.8–37.0 | 3.7–4.6 | 11.7–15.9 | 3.0–4.7 | 73–82 | 1 pair | Absent | - | - | Zhao, 2011 |
| tukorehe 1088 –1149 | 38.5–47.1 | 3.8–4.1 | 11.4–14.8 | 3.9–4.9 | 72–76 | No | Absent | - | - | Zhao,2011 |
| veracruzense 1000 –1100 | 41–54 | 4.7–6.7 | 10–17 | 3.0–6.5 | 74–78 | No | Present | - | - | Cid del Prado-Vera et al. 2010 |
| waiotama 675–908 | 32–41 | 4.0–5.1 | 10.9–15.6 | 3.4–4.5 | 79–83 | 1 single | Absent | - | - | Zhao, 2011 |
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