Procamallanus (Spirocamallanus) tomsici Ramallo & Ailán Choke

Ramallo, Geraldine, Cancino, Fabiana, Ruiz, Ana Lía & Ailán-Choke, Lorena Gisela, 2020, Gastrointestinal nematodes of freshwater fish from Pilcomayo River, Argentina including description of a new species of Procamallanus (Spirocamallanus), Zootaxa 4810 (3), pp. 468-480 : 469-470

Procamallanus (Spirocamallanus) tomsici Ramallo & Ailán Choke

( Figs. 1–2 )

Type material. Holotype: female CH-N-FML #07766; allotype: male CH-N-FML #07767; paratypes (four females, five males) CH-N-FML#07768.

Type host. Pimelodus albicans Valenciennes, 1840 ( Siluriformes , Pimelodidae ), Ichthyology Collection CI- FML #2472, collected 1 December 1997.

Additional hosts: Pygocentrus nattereri Kner, 1858 ( Characiformes , Serrasalmidae ), Ictiology Collection CI- FML #2749, collected 6 October 1998; Hoplias misionera ( Characiformes , Erythrinidae ) Ichthyology Collection CI-FML #2471 (54)).

Type locality. Misión La Paz, Pilcomayo River, Rivadavia Department , Province of Salta (22º22’10”S- 62º32’14”W) .

Etymology. The new species is named in honor Dr. Zlatko Tomsic (1923-2000), professor of Invertebrates (Fac. of Cs. Naturales e I.M.L, U.N.T) and Director of the Institute of Invertebrates of Fundación Miguel Lillo.

Site of infection. Intestine.

Quantitative descriptors. P. albicans (Prevalence 60%; media intensity 6.5); P. nattereri (Prevalence 67%; mean intensity 4); H. misionera (Prevalence 17%; mean intensity 2)

General description. Medium-sized nematodes with finely, transversely striated cuticle. Females possess a lateral cuticular ornamentation along the body ( Figs.1f ; 2c, d, e, f ). Mouth aperture rounded, surrounded by six visible pores, eight submedian cephalic papillae arranged in two circles, each formed by four papillae, and two medium amphids ( Fig. 1c ; 2a ). Buccal capsule orange-brown, thick walled, barrel-shaped, oral capsule has the same length as width, with simple well developed basal ring; wall of middle part of capsule strengthened by conspicuous thickening appearing in lateral view as drop-shaped, extending anteriorly to anterior margin of capsule. Inner surface of capsule of both sexes provided with 3-4 spiral ridges in lateral view, 1-3 of them being incomplete (not extending from 1 lateral margin of capsule to other) ( Figs. 1a, b, d, e ). Muscular esophagus somewhat shorter than glandular esophagus; both parts of esophagus slightly expanded near their posterior ends ( Figs.1a, b ). Intestine narrow. Deirids small, simple, with globose shape situated at about mid-way between posterior end of buccal capsule and nerve ring ( Fig. 2b ); only observed in females. Excretory pore approximately at the middle region of the muscular esophagus ( Figs. 1a, b ). Tail of both sexes, conical.

Males (based on eleven adult specimens). Length of body 12.03±0.80 (10.55–13.19), maximum width 0.17±0.02 (0.14–0.20). Buccal capsule 0.05±0.003 (0.05–0.06) long and 0.05±0.003 (0.05–0.06) wide with 3–4 inner spiral thickenings, 1-3 of them being incomplete. Basal ring 0.01±0.002 (0.010) long and 0.03±0.005 (0.02-0.04) wide. Muscular esophagus 0.56±0.06 (0.50–0.70) long. Glandular esophagus 0.84±0.07 (0.75–0.90) long. Nerve ring and excretory pore 0.22±0.02 (0.20–0.27), 0.30±0.04 (0.22–0.33), respectively, from anterior extremity. Spicules unequal and very different in length, with pointed distal ends; left spicule 0.25±0.01 (0.25–0.27) long and right spicule 0.72±0.01 (0.71–0.73) long. Posterior end of body ventrally bent, provided with narrow caudal alae, 0.40 long and 0.03 long. This structure is supported by two pairs of pedunculate preanal papillae; and three pairs of sessile postanal papillae. Gubernaculum absent. Tail conical 0.12±0.02 (0.10–0.15) long ( Figs.1i, j ; 2g ).

Females (based on nine gravid specimens). Length of body 22.00±2.1 (19.00–25.00), maximum width 0.34±0.06 (0.24–0.43). Buccal capsule 0.06±0.01 (0.06–0.08) long and 0.06±0.01 (0.05–0.07) wide with 3–4 inner spiral thickenings, 2-3 of them being incomplete. Basal ring 0.01±0.01 (0.01–0.012) long and 0.03±0.004 (0.03–0.04) wide. Muscular esophagus 0.63±0.04 (0.57–0.71) long. Glandular esophagus 1.09±0.13 (0.89–1.30) long. Nerve ring, excretory pore and deirids 0.24±0.02 (0.21–0.28), 0.39±0.07 (0.30–0.48), 0.10, respectively, from anterior extremity. Vulva 14.1±1.2 (12.4–15.53) from posterior end. Vulva pre-equatorial and very conspicuous. ( Figs. 1f ; 2c ) Vagina directed posteriorly. Uterus filled with first-stage larvae (0.2-0.3 long x 0.02 wide) ( Fig. 1g ). Conical tail of females with a terminal cuticular spike, 0.12±0.02 (0.10–0.15) long ( Figs. 1h ; 2e, f ).

Figures

FIGURE 1. Procamallanus (Spirocamallanus) tomsici sp. nov. a: Male, anterior end, lateral view. b: Female, anterior end, lateral view. c: Female, apical view. d: Male, head, lateral view. e: Female, head, lateral view. f: Female, vulva, lateral view. g: Larva. h: Female, tail, lateral view. i: Male, posterior end with spicules, lateral view. j: Male, posterior end with spicules and papillae, ventral view.

FIGURE 2. Procamallanus (Spirocamallanus) tomsici sp. nov. (SEM micrographs) a: Female, cephalic end. Six pores (discontinuous white arrows), amphids (discontinuous black arrow), papillae (black arrows). Scale=3 µm. b: Deirid. Scale= 1 µm. c: Female, vulva, subventral view. Scale=30 µm. Lateral cuticular ornamentation. (White arrows) d: Female, cuticular ornamentation, lateral view (white arrows). Scale=10µm. e: Female, anus, lateral-ventral view. Scale=10µm. f: Female, posterior end, lateral-dorsal view. Scale=6 µm. g: Male, posterior end, ventral view. Scale=10µm