Class Monogenea (van Beneden, 1858)
Family Capsalidae Baird, 1853
Genus Encotyllabe Diesing, 1850
Encotyllabe yamagutii n. sp.
Type-host: Pagrus pagrus (Linnaeus) (Perciformes: Sparidae), red porgy.
Type-locality: Cabo Frio, Rio de Janeiro, Brazil (22°55’S, 41°58’W).
Type-material: Holotype (CHIOC xxxxxxx) and 3 paratypes (CHIOC xxxxx – xxxxxx) were submitted to the Helminthological Collection Instituto Oswaldo Cruz.
Site in host: Pharyngeal plates.
Prevalence and intensity: Prevalence: 69%; mean intensity 1.5.
Representative DNA sequences: MT968928 (LSU rRNA)
Etymology: This species is named in honor of Dr. Satyu Yamaguti for his distinguished contributions to the study of monogeneans.
Description
[Measurements based on nine mounted and stained adult worms]. Body ellipsoidal 1.77‒2.50 (1.94) long; 700‒1120 (890) wide. Anterior attachment organs bearing two muscular suckers, 150 (130‒180) in diameter, in each anterolateral margin of the head region and surrounded by an incomplete membrane. Haptor pedunculate, bell-shaped 450‒590 (490) in diameter, with thin marginal membrane 27‒39 (35) long, peduncle 620 (560‒650) long (Fig. 1A). Haptor armed with a pair of large hamulus, 210‒270 (250) long; small hamulus 29‒32 (30) long and 14 homogeneously distributed marginal hooklets 11‒15 (13) long (Fig. 1 C-E). Mouth surrounded by digitiform processes leading to a pharynx of irregular shape and 170‒240 (230) in diameter. Intestinal caeca branched not confluent posteriorly. Two pairs of eyespots at the level of pharynx. Testes oval, side by side and anteriorly midlevel of body proper 250‒360 (300) long and 140‒240 (210) wide. Goto’s glands not observed. Vas deferens sinistral winding anteriorly, entering at the base of the penis and enlarging to form an internal seminal vesicle. Prostatic duct joins ejaculatory duct and opens at the tip of the penis. Penis muscular 240‒340 (300) long; 90‒110 (100) in wide, penis with prolongation oriented to the anterior region of the body. Genital pore ventral on the left side of the pharynx. Ovary oval, pretesticular, immediately posterior to the vitelline reservoir 90‒160 (120) long, 130‒190 (170) wide, with an intraovarian seminal receptacle (Fig.1 B). Uterus extends anterolaterally along the posterior wall of the penis bulb. Ootype not observed, apparently hidden by Mehlis’ gland, slender uterus opens at genital pore. Vaginal pore on ventral side at level of vitelline reservoir; ducts not observed. Vitelline reservoir preovarian on the left side. Vitelline follicles extensive laterally and median fields, from penis to base of peduncle. Eggs not observed.
Differential diagnosis
Encotyllabe yamagutii n. sp. resembles those species with testes side by side, located anterior to the midlevel of the body, and a peduncle larger than the haptor diameter, namely, E. spari and E. antofagastensis. The main differences between the new species and the abovementioned species are the shape of the penis with a projection near the genital pore in the new species and the body size, with E. yamagutii being smaller (1.94 mm) than E. spari (3.14 mm) and E. antofagastensis (2.43 mm). Moreover, the vitelline receptacle is definitively preovarian in E. spari and E. antofagastensis but anterolateral in the new species. Molecular analysis of concatenated genes shows that E. antofagastensis and E. yamagutii are well discriminated species (Fig. 3). Unfortunately, molecular data for E. spari are not available in GenBank,
The type host for E. spari is Sparus microcephalus (Sparidae), but it is also found in two non-related hosts in the Inner Sea (Japan): the haemulid Plectorhynchus pictus and serranid Epinephelus akaara. The type host for E. antofagastensis is the haemulid Anisotremus scapularis from the southeastern Pacific. The new species is also a parasite of a sparid (Pagrus pagrus) but from the coast of Brazil.
Examination of specimens from P. pagrus identified by several authors as E. spari (CHIOC 34531) has revealed that they in fact belong to the new species.
Encotyllabe haemulii n. sp.
Type-host: Orthopristis ruber (Cuvier) (Perciformes: Haemulidae), corocoro grunt.
Type-locality: Cabo Frio, Rio de Janeiro, Brazil (22°55’S, 41°58’W).
Type-material: Holotype (CHIOC xxxxxxx) and 3 paratypes (CHIOC xxxxx – xxxxxx) were submitted to the Helminthological Collection Instituto Oswaldo Cruz.
Site in host: Pharyngeal plates.
Prevalence and intensity: Prevalence: 100%; mean intensity 4.75.
Representative DNA sequences: MT968927 (LSU rRNA), MT967362, MW000907-MW000909 (cox1)
Etymology: This species is named after the host family.
Description
Encotyllabe haemuli n. sp.
[Measurements based on 16 stained and mounted adult worms]: Body bell-shaped, tapered anteriorly and wide posteriorly 2.74‒3.60 (3.19) long; 810‒1.65 (1.23) wide. Anterior attachment organs bearing two muscular suckers 180‒300 (250) in diameter, in each anterolateral margin of the head region and surrounded by an incomplete membrane. Haptor pedunculate, bell-shaped 470‒780 (660) in diameter, with a thin marginal membrane 45‒76 (62) long, peduncle 650‒400 (540) long (Fig. 2A). Haptor armed with a pair of large hamuli 250‒340 (280) long; small hamulus 24‒30 (28) long and 14 homogeneously distributed marginal hooklets 10‒13 (12) (Fig. 2 D-F). Mouth surrounded by digitiform processes leading to a globular pharynx 270‒450 (390) in diameter. Intestinal ceca branched not confluent posteriorly. Two pairs of eyespots at the level of the pharynx. Testes oval, side by side and anteriorly midlevel of body proper 130‒180 (150) long and 100‒170 (120) wide. Goto’s glands not observed. Vas deferens sinistral winding anteriorly, entering at the base of the penis, enlarging to form an internal seminal vesicle. Prostatic duct joins ejaculatory duct and opens at the tip of the penis. Penis muscular 180‒230 (210) long and 89‒120 (110) wide. Genital pore ventral on the left side of the pharynx. Ovary oval, pretesticular, immediately posterior to the vitelline reservoir, 170‒210 (180) long and 180‒260 (220) wide, with an intraovarian seminal receptacle (Fig. 2B). Uterus extends anterolaterally along the posterior wall of the penis. Vaginal pore on ventral side of the vitelline reservoir; ducts not observed. Vitelline reservoir preovarian, sinistral. Vitelline follicles extensive laterally and in median fields, from the pharynx to the base of peduncle. Eggs pyramidal, with 4 long and twisted filaments (Fig. 2C).
Differential diagnosis
Only two species of Encotyllabe have been described with testes smaller than the ovary, namely, E. embiotocae and E. caranxi. Of those, E. caranxi is the longest species described in the genus (11.26 mm); the type host is a carangid (Caranx lutescens) from the Great Barrier (Australia), whereas the type host for E. haemuli is a haemulid from the coast of Brazil. The relationship between large and small haptoral hooks in E. embiotocae varies between 6.8:1 on average, whereas this value reaches 10:1 in the new species, with the smaller hooks in the new species being proportionally smaller.
Specimens of Encotyllabe previously identified as E. spari from Anisotremus virginicus, Conodon nobilis and Haemulon sciurus deposited in CHIOC and identified as E. spari in fact belong to the new species. Specimens identified as E. spari [17] also belong to E. haemuli.
Morphometric analysis
Figure 3 presents the plot of specimens in the bidimensional axis of the PCA. The first and second components explain 59.5% of the total variance. The first component explains 37.3% of the variance and was mainly associated with the proportional morphometric measurements of the ovary width/BL, attachment organs average/BL, testes length/BL, testes width/BL, large hamulus length/BL, and marginal hooks length/BL. The second component explains 22.2% of the variance and was associated with haptor diameter/BL and body width/BL. The new species, E. yamagutii and E. haemuli, showed some overlap but were clearly differentiated.
Molecular and phylogenetic analyses.
For the LSU rRNA, five sequences were obtained, three from E. haemuli (852 bp) and two from E. yamagutii (865 bp). The intraspecific genetic variability for both species was 0%. Four sequences for cox1 were obtained from E. haemuli (437 bp long). Concatenated analysis based on ML and BI produced trees with similar topology (Fig. 4). Each of the new species was statistically supported in independent clades (ML>90; BI>0.9). Table 2 indicates pairwise genetic divergence for LSU rRNA and the cox1 gene.