Neotrop. Helminthol., 8(1), 2014

2014 Asociación Peruana de Helmintología e Invertebrados Afines (APHIA)

ISSN: 2218-6425 impreso / ISSN: 1995-1043 on line

ORIGINAL ARTICLE / ARTÍCULO ORIGINAL

A NEW SPECIES OF TRINIBACULUM (MONOGENEA: DACTYLOGYRIDAE) PARASITE OF

THE GILLS OF ASTYANAX FASCIATUS (CUVIER, 1819) (CHARACIFORMES: CHARACIDAE)

IN A NEOTROPICAL RIVER, SÃO PAULO STATE, BRAZIL

UNA NUEVA ESPECIE DE TRINIBACULUM (MONOGENEA: DACTYLOGYRIDAE) PARÁSITO

(Monogenea: Dactylogyridae) parasite from the gills of Astyanax fasciatus (Cuvier, 1819) (Characiformes: Characidae) in a

Neotropical river, São Paulo State, Brazil. Neotropical Helminthology, vol. 8, n°1, jan-jun, pp. 85 - 95.

Narciso et al.

A new species of Trinibaculum

Clave de identificación - Filogenia -

approach (Reis et al., 2003) and also the

family, the genus Trinibaculum Kritsky,

Thatcher & Kayton, 1980 is characterized by

showing double dorsal bars, dextro-lateral

vagina, confluent intestinal caecum and

intercecal gonads, as proposed by Kritsky et al.

(1980). Species of this genus have been recorded

in Characiformes fishes, such as Bryconidae,

Anostomidae and Characidae families.

To date, three other species of the genus

Trinibaculum have been described:

Upper Paraná River floodplain, Paraná State

Fishes show a considerable diversity of

associate parasite organisms and the class

Monogenea Bychowsky, 1937 is an important

group of ectoparasites of Neotropical fishes

(Eiras et al., 2010). The interest in studying

monogeneans has been updated considering the

amount of publications describing new species

or even approaching aspects like pathology,

ecology and evolutionary relations.

Boeger, 1989; Simková et al., 2003).

Currently, approximately 365 monogeneans

species are described from Brazil (Cohen,

2013). Although, this number might be

underestimated given the remarkable diversity

of hosts from the Neotropical region that have

not been surveyed yet from a parasitological

(Karling et al., 2011); and Trinibaculum

altiparanae Abdallah, Azevedo & Silva, 2013 in

(Cuvier, 1819) from the Paranapanema River,

Jurumirim reservoir, São Paulo State, Brazil,

and presents a phylogenetic hypothesis for the

genus Trinibaculum. An identification key for

the known species of the genus Trinibaculum is

also provided.

Eighty specimens of A. fasciatus were captured

from April/2011 to October/2011 with gillnets in

r e m o v e d a n d a n a l y z e d u s i n g a

stereomicroscope. The parasites found were

stored in flasks with 70% ethanol. Some parasite

samples were mounted in Hoyer to visualize the

sclerotized structures (Eiras et al., 2006). The

morphological analyses and photomicrographs

of the parasites were obtained using the

Differential interference contrast microscopy

(Leica DMLB 5000, Leica Microsystems,

Wetzlar, Germany). The illustrations were made

are presented as: mean in micrometers ±

standard error followed by the amplitude and

number of the specimens measured in

parentheses. The ecological data of prevalence,

mean intensity of infestation and mean

Neotrop. Helminthol., 8(1), 2014

abundance for the monogeneans collected on the

gills of A. fasciatus are in accordance with Bush

Type specimens were deposited in the National

Research Institute of Amazon - Instituto

Nacional de Pesquisas da Amazônia (INPA),

Manaus, Amazonas State, Brazil and in the

Helminthological Collection of the Bioscience

Narciso et al.

A new species of Trinibaculum

Neotrop. Helminthol., 8(1), 2014

Narciso et al.

A new species of Trinibaculum

ventral anchors. Ventral anchor with well-

defined roots, shaft moderately curved, tip

recurved, 32.8 ± 0.56 (29.6-35.7; n=14) long,

base 12.3 ± 0.5 (9.1-15.6; n=16) wide; anchor

filaments extending from shaft to the beginning

of the tip in the lateral edge. Dorsal anchor with

superficial root well developed and short deep

root; shaft and tip curved, 10.3 ± 0.3 (9.4-11,1;

n=6) long, base 8.3 ± 0.2 (7.1-9.5; n=13) long.

Ventral bar yoked-shaped, 34.6 ± 0.86 (32.1-

different in size and shape; pairs 1 and 5 - 19,2 ±

0,6 (13,8 - 23,4; n=) long, widened in about of

1/2 of the shaft length, depressed thumb, tip and

lamina curved; pairs 2, 3, 4, 6 and 7 - 22.1 ± 0.4

(14.6-28.6; n=51) long; widened in about 2/3 of

the shaft length, depressed thumb, tip and lamina

curved. Hook filament extending up to 1/3 of the

stem length. Cirrus coiled with approximately 1

1/2 rings counterclockwise, total length 74.6 ±

3.4 (62.5-85.6; n=6), and diameter of first ring

distal bulbous (Fig. 2). Vitellaria distributed

throughout the trunk except in the area of the

gonads and male copulatory complex. Eggs not

observed.

Type-host: Astyanax fasciatus (Cuvier, 1819)

(Characiformes: Characidae).

Locality: Paranapanema River, Jurumirim

reservoir (23°28'20.28"S 48°38'34.40"W -

Google Earth), Angatuba municipality, São

125L, 126L, 127L and 128L.

Etymology: The specific epithet refers to the

characteristic accessory structure shaped as

tweezers from the Latin (pinctiare = pinch).

Trinibaculum pinctiarum n. sp. is similar to T.

altiparanae due to the following characteristics:

cephalic lobes moderately developed, eyes

disposition (similar in size with the members of

the posterior pair of eyes close to each other),

tweezers (considerable curved and basally bifid

in T. altiparanae), post-median process in the

ventral bar absent (present in T. altiparanae),

hooks with depressed thumb (erected thumb in

T. altiparanae).

This new species differs from the others of the

genus because it presents fusiform body (disc

shaped in T. rotundus), cephalic lobes

moderately developed (incipient in T.

brazilensis and T. rotundus), eyes similar with

T. rotundus), deep root of the dorsal anchor short

(long in T. brazilensis and T. rotundus), dorsal

bar with widened ends laterally directed (simple

in T. brazilensis and T. rotundus), hooks with

approximately 2/3 of widened shank and

depressed thumb (straight thumb in T.

brazilensis, and slender shaft T. rotundus).

1a - Body disc-shaped; peduncle absent; point of

the dorsal anchor well-recurved; dorsal anchor

the dorsal anchor slight or moderately curved;

dorsal anchor with point extending to the next

half of the length of the superficial root and no-

widened superficial root; ventral bar in U or V

shape; hook shank with proximal widening;

cirrus as simple tube or coiled with

counterclockwise rings………….....................2

2a (1b) – Incipient cephalic lobes; four eyes in

which the members of the posterior pair of eyes

are bigger and more distant to each other than the

member of the anterior pair of eyes; deep root of

3a (2b) - Post-median process prominent in the

ventral bar and ends with striae; hooks of

different sizes, in which the pairs 1, 2 and 5 are

smaller and straight thumb; Cirrus in simple

tube; accessory structure well-curved

posteriorly bifid and piece flabellate

anteriorly……………..................Trinibaculum

altiparanae

tweezers.............Trinibaculum pinctiarum n. sp.

Neotrop. Helminthol., 8(1), 2014

Narciso et al.

A new species of Trinibaculum

bar; (F) Dorsal anchor; (G) Hook.

Neotrop. Helminthol., 8(1), 2014

The most parsimonious cladogram for the

relations of the species within Trinibaculum

(Fig. 6). Trinibaculum pinctiarum n. sp. is a

sister group of T. altiparanae supported by five

sinapomorphies (A, B, G, H and J) with

Consistency index = 100%, corroborating the

great similarity between the two fish parasite

species of the genus Astyanax, however, the

character E (male copulatory organ)

Consistency index = 50 % in T. altiparanae with

T. brazilensis both present copulatory organ,

being characterized as a probable reversion in

Trinibaculum pinctiarum n. sp.), supported by

two sinapomorphies (C and L) IC = 100%.