Temnocephala chilensis ( Moquin-Tandon, 1846 ) Blanchard, 1849

León, Rodrigo Ponce De, Rudolph, Erich H. & Volonterio, Odile, 2020, On a new Temnocephala (Platyhelminthes) from Southern Patagonia (Chile, Argentina), with a redescription of T. chilensis and some systematic and biogeographical insights *, Zootaxa 4852 (3), pp. 383-395 : 388-391

Temnocephala chilensis ( Moquin-Tandon, 1846) Blanchard, 1849

( Figs. 3–4 ; Tables III, IV)

Synonymy: Branchiobdella chilensis Moquin-Tandon, 1846

Astacobdella chilensis Diesing, 1850

Temnocephala tumbesina Wacke, 1905

Material studied. Thirty-three whole mounts, 17 dissections of the reproductive complex and mounts of 15 eggs made with material found on Aegla alacalufi Jara and López, 1981 ( Decapoda, Anomura , Aeglidae ) from Burritos River (43°24’S; 72°21’W), Palena Province, X Región (also known as ‘Región de los Lagos’), Chile (coll. Erich Rudolph, 21 January, 1999).

Deposited material. Whole mounts ( CHFC /AP 12720–12752), mounts of dissections of the reproductive complex ( CHFC /AP 12753–12769) and eggs ( CHFC /AP 12770) are deposited in the CHFC (Universidad de la República), Montevideo, Uruguay.

Description. Body length excluding tentacle length 1,400.8 µm (Table III). Width 1,073.7 µm at level of anterior testes. Eyes red. Four Haswell’s cells ( Fig. 3A ). Circular sucker, 366.1 µm in diameter. Sucker peduncle diameter 184.2 µm. Numerous sucker glands extending posteriorly from level of posterior testes to sucker peduncle, surrounding it partially. Ratio total body length to main sucker diameter 3.8:1 (Table IV). Tentacular glands extending from level of excretory bladder to level of posterior testes, with higher density at level of intestinal sac ( Fig. 3A ). Paranephrocyte pattern: two large cells close to posterior portion of posterior testes ( Fig. 3A ). Oval pharynx, length 401.9 µm, width 359.3 µm; posterior sphincter larger than the anterior one; with a wide pharyngeal lumen. Intestinal sac with 3–5 lateral folds, usually forked distally.

Testes elliptical, anterior testes length 180.0 µm, width 136.8 µm. Posterior testes length 272.7 µm, width 179.2 µm. Seminal vesicle length 175.5 µm, width 70.8 µm, joined to contractile vesicle in a clearly lateral position ( Fig. 3B ). Contractile vesicle length 180.4 µm, width 84.2 µm. Penial stylet total length 161.7 µm, basal width 57.0 µm. Introvert length 46.2 µm, width 62.7 µm, with 39–45 spine-like projections. Each projection gives rise to 9–10 internal spines, the more distal ones being progressively shorter ( Figs. 4A,B ). Introvert highly asymmetrical in lateral view, with a longer (dorsal) and a shorter (ventral) side ( Fig. 4A ); on the longer side the spine-like projections are longer and thicker than on the shorter side, giving an asymmetrical spatial arrangement ( Fig. 4A,B ). The shaft and introvert of the penial stylet are at an angle of 160.2°. Ratio penial stylet length to basal width 2.8:1, penial stylet length to contractile vesicle length 0.9:1, non-everted introvert diameter to penial stylet basal width 1.1:1.

Ovary length 141.6 µm, width 98.5 µm; resorbens vesicle length 146.0 µm, width 110.8 µm. Vagina strongly muscular, with asymmetrical distal sphincter ( Fig. 3B ). Abundant glandular cells surrounding the proximal end of the vagina, with ducts that open into its lumen ( Fig. 3B ). Eggs elliptical, pedunculated, with an apical, curved, sclerotized filament ( Fig. 4C ); deposited on coxal region and between hosts’ eyes. Egg length 561.5 µm, width 334.5 µm.

Remarks. All the material identified as T. chilensis in this work agrees with the redescription made by Dioni (1967a, c), with part of the material studied by Wacke (1905) and with part of the specimens from Aegla neuquensis (Neuquén Province) assigned to T. chilensis by Damborenea (1991, 1992). In general, our specimens were larger than those described by Dioni (1967a, c), but smaller than those studied by Damborenea (1992). In contrast, Damborenea (1992) reports a mean size of the penial stylet (149 µm) that is smaller than the one reported in Dioni (1967a, c) (165µm) and the present study (162 µm). Damborenea (1991, 1992) and Damborenea & Cannon (2001), reviewing the Argentinean species of Temnocephala , stated that the specimens of T. chilensis and T. talicei lacked a vaginal sphincter, but in all the specimens of T. chilensis studied in the present work a conspicuous vaginal sphincter was observed. This is also true for T. talicei , as shown by Volonterio (2007a, 2009) and later confirmed by Seixas et al. (2018).

Only T. dionii and T. monticellii n. sp. share a penial stylet that, at a first glance, could be considered similar with that of T. chilensis . However, there are clear differences; those between T. chilensis and T. dionii were discussed earlier by Ponce de León et al. (2015), and those between the former and T. monticellii n. sp. have been stated in this work.

Dioni (1972), in his latest study on Temnocephala from Patagonia, found specimens he assigned to T. chilensis , which had a straight penial stylet and a symmetrical introvert that was smaller than those studied earlier ( Dioni, 1967a, c). Damborenea (1992) later found specimens similar to those of Dioni (1972) in a nearby locality, which were also reported as T. chilensis . As the descriptions made by Dioni (1972) and Damborenea (1992) match with diagnostic features of T. monticellii n. sp., it would be desirable to reexamine material from these hosts and localities in the light of the existence of the new species.

Measurement Range Min Max SD Sample size Body length Body width Sucker diameter Sucker peduncle longitudinal diameter Pharynx longitudinal axis Pharynx transverse axis Anterior testes length Anterior testes width Posterior testes length Posterior testes width Seminal vesicle length Seminal vesicle width Contractile vesicle length Contractile vesicle width Penial stylet total length Penial stylet basal diameter Introvert length Introvert diameter Angle between penial stylet and introvert Ovary length Ovary width Vesicle resorbens diameter Egg length Egg width 1,084.5 1,743.3 861.5 1,388.5 304.1 425.7 142.2 228.5 314.2 486.5 263.5 476.4 76.2 228.5 40.6 203.1 137.1 330.1 86.3 228.1 140.4 204.2 48.5 107.2 127.6 242.5 60.0 107.2 145.5 206.8 43.4 68.9 40.0 59.2 53.6 76.6 148° 167° 102.1 171.0 63.8 127.6 102.1 178.7 516.9 628.4 304.1 354.7 153.3 122.3 27.5 21.63 45.1 45.1 51.1 44.2 57.1 49.9 15.5 11.3 25.5 11.9 11.6 6.6 4.1 4.6 4.9 17.9 15.7 35.1 31.8 14.8 33 33 33 33 33 33 18 18 18 18 17 17 17 17 17 17 17 17 17 17 17 5 15 15 Ratio Range SD Sample size Min Max Body length to sucker diameter 3.2 4.8 0.3 33 Penial stylet length to contractile vesicle length 0.6 1.3 0.2 17 Penial stylet length to basal diameter 2.2 4.2 0.4 17 Introvert diameter to penial stylet basal diameter 0.9 1.4 0.1 17

Diagnosis. Temnocephala chilensis is characterized by having a penial stylet 146–207 µm in length, with a highly asymmetric and wide introvert (54–77 µm in diameter); an introvert with at least 39–45 asymmetrical spine-like projections, each bearing 9–10 internal spines, the more distal ones being progressively shorter; shaft and introvert of the penial stylet are at an angle of 148°–167°; a seminal vesicle that opens laterally into the contractile vesicle; a vagina with an asymmetrical sphincter; a single pair of paranephrocytes close to the distal portion of the posterior testes, and eggs with a polar filament.

Distribution. Locality. Palena Province, X Región (also known as ‘Región de los Lagos’), Chile: Aegla alacalufi Jara and López, 1981 ( Decapoda , Aeglidae ) from Burritos River (43°24’S; 72°21’W), 21 January 1999. Site of infection: body surface, mainly on coxa and eye peduncles. Collector: Erich Rudolph.

Additional hosts and localities in Chile. Osorno Province, X Región: Aegla abtao Schmitt, 1942 and Samastacus spinifrons (Philippi, 1882) from Chifín River (40°46’S; 73°12’W) and Forrahue River (40°49’S; 73°11’W), 17 December 1978; Rahue River (40°44’S; 72°59’), 21 January, 1983; Hueyusca River (41°07’S; 73°37’W), 08 November, 1988. Valdivia Province, X Región: A. abtao Schmitt, 1942 and Samastacus spinifrons (Philippi, 1882) from Ranco Lake (40°11’S; 72°22’W), 20 August, 1988; A. abtao and Aegla rostrata Jara, 1977 from Panguipulli Lake (39°41’S; 72°13’W), 09 September 1989. Curicó Province, VII Región: S. spinifrons from Guaiquillo River (34°59’S; 71°15’W), 16 September 1989. Collector: Erich Rudolph.

Additional hosts and localities in Argentina. Rio Negro Province: Samastacus spinifrons from Puerto Pañuelo (41°03’S; 71°31’W) , Nahuel Huapi Lake, Bariloche, and from 1.5 km east from downtown Bariloche (41°07’S; 71°18’W), 31 January 1983 and 10–21 January 1991 . Neuquén Province: Aegla riolimayana from Arroyo Ñireco (41°04’S; 71°08’W), 10–21 January 1991. Collector: Rodrigo Ponce de León.

Previous reports. Type locality: Santiago Province, Chile, from an unknown crayfish ( Moquin-Tandon, 1846). In Argentina, from Aegla abtao Schmitt, 1942 , Aegla affinis Schmidt, 1942 , Aegla jujuyana Schmitt, 1942 , Aegla neuquensis Schmitt, 1942 , and Aegla scamosa Ringuelet, 1949 ( Dioni, 1967a, c, 1972; Damborenea & Cannon, 2001; Martínez-Aquino et al., 2014). The name T. chilensis was used for specimens of Temnocephala found on Aegla sp. from north-eastern Argentina (Buenos Aires) by Gallardo (1909), in a brief report without a description or figures of the material studied. To date, in this geographic area only T. axenos and T. talicei have been formally reported ( Damborenea, 1992).

In order to facilitate the identification of species of Temnocephala hosted on Aegla and Parastacidae , the following key is provided.

Figures

FIGURE 3. Temnocephala chilensis. (A) Whole specimen in ventral view. Bar = 500 µm. Arrowheads, paranephrocytes. (B) Main reproductive organs in ventral view, drawn from a dissection. Bar = 200 µm. Abbreviations: at, atrium; cv, contractile vesicle; ev, excretory vesicle; go, gonopore; hg, Haswell’s glands; in, intestine; ov, ovary; ph, pharynx; ps, penial stylet; rv, resorbiens vesicle; sg, sucker glands; sp, sphincter; sr, seminal receptacle; su, sucker; sv, seminal vesicle; te, testes; tg, tentacular glands; vg, vagina; vi, vitellaria.

FIGURE 4. Temnocephala chilensis. (A) Non-everted penial stylet in lateral view. Bar = 50 µm. (B) Everted introvert. Bar = 25 µm. (C) Egg. Bar = 250 µm.