ORIGINAL ARTICLE / ARTÍCULO ORIGINAL

TWO NEW SPECIES OF PAVANELLIELLA (MONOGENEA, DACTYLOGYRIDAE)

PARASITIC ON PIMELODID FISHES FROM MOGI GUAÇU RIVER, SOUTHEASTERN

BRAZIL, AND NOTES ON THE MORPHOLOGY OF P. PAVANELLII

DOS NUEVAS ESPECIES DE PAVANELLIELLA (MONOGENEA, DACTYLOGYRIDAE)

PARÁSITOS DE PECES PIMELÓDIDOS DEL RIO MOGI GUAÇU, SUDESTE DE

BRASIL Y NOTAS SOBRE LA MORFOLOGÍA DE P. PAVANELLII

Suggested citation: Aguiar, J.C., Ceccarelli, P.S. & Luque, J.L. 2011. Two new species of Pavanelliella (Monogenea,

Dactylogyridae) parasitic on pimelodid fishes from Mogi Guaçu river, southeastern Brazil, and notes on the morphology of P.

pavanellii. Neotropical Helminthology, vol 5, nº 2, pp. 213-224.

Key words: Ancyrocephalinae – Biodiversity - nasal parasites - Neotropical Region - Pavanelliella laertei sp. n. -

Pavanelliella takemotoi sp. n. - South America.

Dos nuevas especies de Pavanelliella (Dactylogyridae) fueron descritas y algunos detalles sobre la

morfología de Pavanelliella pavanellii Kritsky & Boeger, 1998 se han añadido sobre la base de

especímenes colectados en los peces pimelódidos del rio Mogi Guaçu, Brasil. Pavanelliella takemotoi

morphology of Pavanelliella pavanellii Kritsky & Boeger, 1998 were added based on specimens

collected from pimelodid fishes from Mogi Guaçu River, Brazil. Pavanelliella takemotoi sp. n.,

collected from nasal cavities of Pimelodus maculatus Lacepède, 1803 differs from its congeners by

having a male copulatory organ (MCO) with 2–5 rings, vaginal canal sinuous without loops in distal

portion of vaginal canal and anteriorly directed vagina containing five irregular rings around the

vestibule. Pavanelliella laertei sp. n. collected from P. heraldoi Azpelicueta, 2001 is separated from the

other species of the genus by lacking a vaginal vestibule and by distal end shape of accessory piece,

which resemble flames or is bifurcated with one flank hooked in P. laertei sp. n. The specimens of P.

pavanellii examined in this study showed morphological variations especially on MCO, vaginal canal

and vagina morphology with respect to the holotype and paratype and are noted in this paper.

pero nunca con lazos en la porción distal del canal vaginal y la vagina es dirigida anteriormente y tiene

cinco anillos irregulares alrededor del vestíbulo. Pavanelliella laertei sp. n. colectados de P. heraldoi

Azpelicueta, 2001 se diferencia de las otras especies del género por La falta de un vestíbulo vaginal y

por la forma de extremo distal de la pieza accesoria, que se asemeja a las llamas o se bifurca con un

flanco enganchado en P. laertei sp. n. las muestras de P. pavanellii examinadas en este estudio

mostraron variaciones morfológicas, especialmente en la morfología de OCM, canal vaginal y de la

vagina con respecto al holótipo y parátipo, y se discuten en esta investigación. Todas las diferencias

entre las especies estudiadas fueron confirmadas com el uso del análisis estadístico morfométrico

- Pavanelliella takemotoi sp. n. - Región Neotropical.

Papers about monogeneans parasitic on Brazilian

pimelodids focused on descriptions of

dactylogyrid species infecting gills of the hosts

(Boeger & Vianna, 2006; Cohen & Kohn, 2008;

Monteiro et al., 2010). Kritsky & Boeger (1998)

proposed Pavanelliella Kritsky & Boeger 1998 to

include dactylogyrid species parasitic on nasal

cavities of pimelodid fishes, although later Kritsky

& Mendoza-Franco (2003) described another

putative species which shared based in their

morphological characteristics and performed to

multivariate analysis, to confirm statistically, the

differences between the species observed by us.

Here, two new species of Pavanelliella are

described and new morphological data are added to

P. pavanellii Kritsky & Boeger 1998 from

specimens collected from the nasal cavities of P.

maculatus Lacepède, 1803 and Pimelodus heraldoi

Azpelicueta, 2001 in São Paulo, Pirassununga,

Emas (21º 58'S, 47º 26' W) on Mogi Guaçu River,

Pirassununga, São Paulo. Samplings were carried

out with nets and cast nets. Were collected 57

individuals of P. maculatus (Mean of total length =

26.24 ± 6.14; mean of weight = 258.42 ± 191.85)

and 44 of P. heraldoi (Mean of total length = 12.03

± 2.21; mean of weight = 18.46 ± 12.61). The fishes

were identified according to Britski et al. (1999)

and Azpelicueta (2001). The fish nasal cavities

were disrupted with a probe and washed with

stained with Gomori's trichrome and mounted in

Gray and Wess medium. The identification of the

parasites was carried out use of an optical

microscope with differential interference contrast

(DIC) Olympus BX 51. The illustrations were

made with a drawing tube attached to a phase

contrast microscope Opton™. The measurements

(in micrometers) are represented by the average,

with ranges in parentheses and followed by the

number (n) of specimens. All measurements were

(prevalence, abundance and mean intensity of

infestation) are those suggested by Bush et al.

(1997). Type specimens were deposited in the

Helminthological Collection of the Institute

Oswaldo Cruz (CHIOC), Rio de Janeiro, Brazil.

Morphological features measured were those in

accordance with Kritsky & Mendoza-Franco

performed to verify the variance (Bartlett's test P

levels < 0,05) of the variables values and the

Shapiro-Wilk test (P levels < 0,05) were run for

evaluating normality of data (McGarigal et al.,

2000) using the MYSTAT 12 (2007) (SYSTAT 12

©) also utilized for Principal Component Analysis

(PCA) and a Linear Discriminant Analysis (LDA).

The variables who had significant variance and

non-normal distribution were log (x) transformed.

River, Pirassununga, State of São Paulo, Brazil

in the distal portion. Pavanelliella scaphiocotylus

have a simple vestibule and a vaginal canal with

4–5 loops in the distal portion around the vestibule.

In P. takemotoi sp. n., the vagina is anteriorly

directed and apparently longest, besides having

4–5 irregular rings around of the vaginal vestibule

and lack the loops of the distal portion of vaginal

canal. Pavanelliella takemotoi sp. n. also differs of

P. pavanellii and P. scaphiocotylus by presenting 4

flanges (1–3 flanges in P. pavanellii; 2 flanges in P.

scaphiocotylus because this last species haves a

prominent tissue ridge along anterodorsal haptoral

surface. Additionally P. takemotoi sp. n. has a more

larger MCO (35) than P. pavanellii (23) and a more

larger hook length (16) than P. pavanellii (12) and

P. scaphiocotylus (14).

Diagnosis (based on 2 specimens stained with

Gomori's trichrome and mounted in Grey and

Wess's medium and 5 specimens mounted in Grey

and Wess's medium): Body 334 (274–374; n = 7)

in posterior third of body. Cephalic margin

in diameter; esophagus short; intestinal caeca

confluent posterior to germarium. Haptor 70

(60–79; n = 2) wide, 51 (42 –66; n = 5) long,

comprising delicate extension of postero lateral

trunk velum-like, with rounded tip, differentiated

from trunk by a constriction anterior to seventh pair

of hooks. Hooks 14 (11–17; n = 23), with

terminally expanded protruding erected thumb, a

delicate point, proximal subunit of shank slightly

expanded; filamentous hook loop reaching union

2–3 rings or sometimes with 2 anterior rings and 2

posterior rings in relation to accessory piece; base

with 2–4 flanges. Accessory piece 20 (18–21; n =

3) long, comprising sheath enclosing distal or

medial portion of MCO, with irregular distal end

flame-like or bifurcated with one of them hooked.

Germarium elongate 57 (38–86; n = 3) long, 18

(10–29; n =3) wide, oval; oviduct, ootype, not

observed. Vagina sinistroventral, vaginal vestibule

not observed; vaginal canal sclerotized, elongate,

mandi branco (Siluriformes, Pimelodidae).

Site of infection: Nasal cavity.

Type locality: Cachoeira de Emas, Mogi Guaçu

River, Pirassununga, State of São Paulo, Brazil (21º

58'S; 47º 26' W).

Prevalence of infection: 14%.

Mean intensity of infection: 1.5.

Mean abundance of infection: 0.2.

Specimens deposited: Holotype (CHIOC 37561),

paratypes (CHIOC 37562, 37563, 37564, 37565,

Etymology: The specific name is in honor to Laerte

However, the new species is different from all

congeneric species because Pavanelliella laertei

sp. n. lacking a vaginal vestibule. Moreover,

Pavanelliella laertei sp. n. has a larger hook (14)

and MCO length (43) than P. pavanellii (12 and 23,

respectively). But, the accessory piece length of P.

laertei sp. n. (20) is lower than P. pavanellii (27).

Although P. scaphiocotylus has the same hook

length (14) of P. laertei sp. n., the former species

has a prominent tissue ridge along anterodorsal

flame-like and hooked distal ends never are present

on these last three species. Additionally, P. laertei

sp. n. was found in another host species, Pimelodus

heraldoi, which to date hadn't a parasitological

Pavanelliella pavanellii Kritsky & Boeger, 1998

(Figs. 16–18)

Diagnosis (based on 9 specimens: 1 stained with

Gomori's trichrome and mounted in Grey and

Wess's medium, 8 mounted in Grey and Wess's

ring diameter. Accessory piece 27 (18–48; n = 4)

long. Germarium 55 (40–77; n = 4) long, 16 (9–23;

n = 4) wide.

Taxonomic summary

Host: Pimelodus maculatus Lacepède, 1803,

mandi amarelo (Siluriformes, Pimelodidae).

Site of infection: Nasal cavity.

Locality: Cachoeira de Emas, Mogi Guaçu River,

Pirassununga, Brasil (21º 58'S e 47º 26' W)

Prevalence of infection: 14%.

Mean intensity of infection: 1.25.

The specimens of P. pavanellii collected from

Mogi Guaçu River and examined on this study

showed morphological differences in MCO,

vaginal canal and vagina compared to the

descriptions and deposited material of Kritsky &

Boeger (1998). The accessory piece described by

Kritsky & Boeger (1998) has a proximal lobe. In

the specimens observed by us this proximal lobule

was less developed or even absent as the accessory

were sclerotized, but they gave not any information

about the MCO base flanges existence. We

observed the presence of 3 sclerotized flanges in

our specimens, one proximal and 2 distal, and the

exam of the holotype and paratype described

above, revealed the presence of 2 miniature flanges

at distal margin of MCO of paratype and one in

each margin of holotype. The vagina of the

specimens examined by us shows a large vaginal

vestibule, only observed in the paratype. The

the holotype and one paratype, and, although

series of P. pavanellii can show more

morphological diversity.

In many researches the data collinearity of

collinearity of variables can not be useful for

morphometric multivariate analysis because it

contribute to the same direction in the species

discrimination. In present paper we used the non-

collinearity of data and this resulted on well species

distinctiveness.

smaller specimens had a minor MCO, and lacking

belong to different species, we consider more

careful to keep them as intra-specific

morphological variations, especially given the

similarity of the morphology of the vagina.

1819) collected from Solimões River in the State of

scaphicotylus Kritsky and Mendoza-Franco, 2003,

collected from the Yucatán Peninsula in Mexico,

parasitizing nasal cavity of R h am d ia

guatemalensis Kritsky & Mendoza-Franco, 2003

(Kritsky & Mendoza-Franco, 2003).

Currently, Pavanelliella species are distributed in

fishes from 3 siluriform genera (Boeger & Vianna,

2006). As siluriforms are very speciose in the

neotropics (Lundberg & Littmann, 2003), new

records and new Pavanelliella species will

Table 1. Categorical variables of Pavanelliella spp. Minimum and Maximum number of MCO ring (Ringmin; Ringmax); Vaginal

vestibule (Vagvest; 1 = present; 0 = absent); Minimum and Maximum number of loops of the distal portion of the vaginal canal

(Canvagmin; Canvagmax); Distal end of accessory piece (Single = Accsing; Partite = Accpart; Flamed = Accflam; Hooked =

Acchook; 1 = present; 0 = absent).

Table 2. Canonical discriminant functions of categorical and continuous variables of Pavanelliella spp. selected by backward

stepwise LDA.

Figures 1–8. Pavanelliella takemotoi sp. n. 1. Whole mount, dorsal view. 2–4. Compulatory complex: ventral view. 5. Base of

MCO. 6. Hook. 7–8. Vagina, dorsal view. Scale bars: 100 µm (Fig. 2) and 20 µm (Figs. 3–9). PHARYNXD = Pharynx diameter;

ACCPIECEL = Accessory piece length; PRINGD = Proximal ring diameter; MCOL = Male copulatory organ length; HOOKL =

Hook length

Figures 9–15. Sclerotized structures of Pavanelliella laertei sp. n. 9. Copulatory complex, dorsal view. 10. Hook. 11. Vagina,

dorsal view. 12–13. Copulatory complex, left side and ventral view, respectively. 14. Hook. 15. Vagina, ventral view. Scale bars:

25 µm (Fig. 12, 16), 20 µm (Figs.10, 13–14), and 15 µm (Figs. 11,15).

Figures 16–18. Pavanelliella pavanellii Kritsky & Boeger, 1998. 16. Copulatory complex, ventral view. 17. Hook. 18. Vagina and