Gyrodactylus breviradix,

Vega, Rocio, Razzolini, Emanuel, Arbetman, Marina & Viozzi, Gustavo, 2019, Two new species of Gyrodactylus von Nordmann, 1832 (Monogenoidea: Gyrodactylidae) parasitizing introduced poeciliids in Patagonia, Zootaxa 4664 (3), pp. 423-433: 427-430

publication ID

https://doi.org/10.11646/zootaxa.4664.3.9

publication LSID

lsid:zoobank.org:pub:06BEFFC0-EB9E-4B77-97A0-7F3D497EA395

persistent identifier

http://treatment.plazi.org/id/FB2E87F3-FFAB-4F51-FF00-DB8EF2278CBC

treatment provided by

Plazi

scientific name

Gyrodactylus breviradix
status

n. sp.

Gyrodactylus breviradix  n. sp.

( Figs 6–10View FIGURES 6–10, 12View FIGURES 11–12, Table 1)

urn:lsid:zoobank.org:act:8DE2A9EA-BDD7-4980-924E-AF36D14D416D

Type host: Cnesterodon decemmaculatus (Jenyns, 1842)  ( Cyprinodontiformes  : Poeciliidae  ).

Type locality: Neuquen River , Vista Alegre, Neuquen, Argentina (38°59’36.6”S 67°59’31.1”W)GoogleMaps  .

Site of infection: Body surface.

Specimen studied: holotype, MACN-Pa 679; paratypes MACN-Pa 680/1, MACN-Pa 680/2; hologenophore, MACN-Pa 681.

Specimen sequenced: ITS1 (GenBank accession numbers: MK 312262View Materials, MK 312261View Materials), ITS2 (GenBank accession numbers: MK 312259View Materials, MK 312260View Materials), COII (GenBank accession numbers: MN 066552View Materials, MN 066553View Materials)

ZooBank registration: The life Science Identifier ( LSID) Gyrodactylus breviradix  n. sp. is urn:lsid:zoobank.org:act:8DE2A9EA-BDD7-4980-924E-AF36D14D416D .

Etymology: The specific epithet refers to the short superficial root of the anchor.

Description: (Based on 9 specimens) Body elongate, 318 (238–364; n = 8) long, 74 (56–98; n = 9) wide. Cephalic glands, head organs, spike sensilla conspicuous. Cephalic glands anterolateral, lateral, posterolateral to pharynx. Pharynx composed of two tandem bulbs. Distal pharyngeal bulb muscular 26 (22–30; n = 5) wide; digitiform projections of distal pharyngeal bulb not observed; proximal pharyngeal bulb glandular 23 (19–27; n = 5) wide. Male copulatory organ ( MCO) 10 (8–11; n = 3) wide, armed with one spine, one row of two large spinelets, each with wide, ovate base. Testis ovate, 20 (n = 1) wide, overlapped by posterior portion of germarium. Germarium ovate, 11 (10–12; n = 2) long, 15 (10–20; n = 2) wide. Uterus with up to 2 generations of embryos. Syncytial follicles overlapping and immediately posterior to distal portions of caecae. Anchor 41 (36–43; n = 8) long; straight, point recurved; deep root poorly developed, knob-like; short superficial root, inwardly and dorsally recurved. Deep bar with a median notch at posterior edge. Superficial bar 23 (22-25; n = 3) long, 25 (22–27; n = 3) wide, with two robust, elongate anterolateral projections, folded inward; trapezoidal shield. Hook, 27 (26–29; n = 7) long with straight shank. Hooklet 6 (5–6; n = 4) long; point short, 90º angled, ending before level of toe tip; short uniform shafts; heel round, prominent; toe pointed, depressed; shelf convex; FH loop about 1/4 of shank length.

Remarks: Gyrodactylus breviradix  n. sp. resembles Gyrodactylus xalapensis Rubio-Godoy, Paladini  , García- Vásquez & Shinn, 2010, Gyrodactylus mexicanus Mendoza-Palmero, Sereno-Uribe & Salgado-Maldonado, 2009  , and Gyrodactylus takoke García-Vásquez, Razo-Mendivil  , & Rubio-Godoy, 2015, having certain similarities in hooklet morphology ( Figure 12View FIGURES 11–12). Gyrodactylus xalapensis  differs by having a circular to sub-square heel, a shorter, robust toe, and a slightly upward-curved hooklet point ( Rubio-Godoy et al., 2010). Additionally, G. xalapiensis  has an MCO with four spinelets ( Rubio-Godoy et al., 2010). Gyrodactylus mexicanus  differs by having hooks with a proximally-disrupted proximal ligament, a shorter hooklet shaft with a recurved point, and the superficial roots of anchors folded posteriorly with grooves ( Mendoza-Palmero et al., 2009). Gyrodactylus takoke  differs from G. breviradix  n. sp. by having a straight point of the hooklet facing downwards and ending at the toe limit, a smaller hooklet ( Table 1), and a superficial bar with a triangular shield ( García-Vásquez et al., 2015).

Gyrodactylus breviradix  n. sp. hooks also resemble G. carolinae  , Gyrodactylus lebiasinus An, Jara & Cone, 1991  , and Gyrodactylus bimaculatus An, Jara & Cone, 1991  which parasitises characiform fishes, and Gyrodactylus pimelodellus An, Jara & Cone, 1991  which parasitises siluriform fishes. Gyrodactylus carolinae  differs by having a robust shaft and hooklet point, a recurved hooklet point facing downwards that extends beyond the toe, and a superficial bar with a subtriangular shield ( Boeger et al., 2014). Gyrodactylus lebiasinus  and G. bimaculatus  differ by having a long hooklet point that extends beyond the limit of the toe, and a squarish toe ( An et al., 1991). Additionally, G. bimaculatus  differs by having a subtriangular shield and an MCO armed with 6 spinelets ( An et al., 1991). Gyrodactylus pimelodellus  differs by having a rectangular toe, a depressed heel, an MCO armed with 6 spinnelets, and large, parallel superficial bar projections ( An et al., 1991).

Molecular analysis. The new species described in this work were compared with species that were morphological and genetically similar. Not every species was available for each region of the ITS1 and ITS2, so we based our analyses mainly on the ITS2 region, where more comparisons were available. This was also true for the COII region, where none of the target species (i.e. more genetically or morphologically similar) were available. The genetic p-distances within and between species are shown in Table 2. The trees recovered with both the Maximum Likelihood and the consensus Bayesian Inference tree showed identical topology for the ITS2 region.

Both sequences of G. decemmaculati  specimens clustered in a single group showing no intraspecific distance ( Figure 13View FIGURE 13). The interspecific genetic distances observed between the morphologically similar gyrodactylids from the cyprinodontiform fishes G. unami  , G. turnbulli  , and G. pictae  were similar to those between most of the pairwise comparisons. Sequences of G. breviradix  specimens also clustered in a single group and presented much shorter intraspecific distances (0.007) than those observed between the morphologically similar gyrodactylids from the cyprinodontiform fishes G. xalapensis  (0.085) and G. takoke  (0.092). However, the barcoding gap graph clearly separated G. decemmaculati  from the other species, although for G. breviradix  the p-distances to the smallest inter- specific distance were shorter. Nevertheless, the closest p-distance for G. breviradix  was to G. takoke  but this was still higher than the distance between G. takoke  and G. xalapensis  (0.010) ( Figure 14View FIGURE 14).

MK

National Museum of Kenya

MN

Museu Nacional, Universidade Federal do Rio de Janeiro

FH

Fort Hays

Kingdom

Animalia

Phylum

Platyhelminthes

Class

Monogenea

Order

Gyrodactylidea

Family

Gyrodactylidae

Genus

Gyrodactylus

Loc

Gyrodactylus breviradix

Vega, Rocio, Razzolini, Emanuel, Arbetman, Marina & Viozzi, Gustavo 2019
2019
Loc

Gyrodactylus breviradix

Vega & Razzolini & Arbetman & Viozzi 2019
2019
Loc

G. carolinae

Boeger, Ferreira, Vianna & Patella 2014
2014
Loc

Gyrodactylus carolinae

Boeger, Ferreira, Vianna & Patella 2014
2014
Loc

Gyrodactylus lebiasinus

An, Jara & Cone 1991
1991
Loc

Gyrodactylus bimaculatus

An, Jara & Cone 1991
1991
Loc

Gyrodactylus pimelodellus

An, Jara & Cone 1991
1991
Loc

Gyrodactylus lebiasinus

An, Jara & Cone 1991
1991
Loc

G. bimaculatus

An, Jara & Cone 1991
1991
Loc

G. bimaculatus

An, Jara & Cone 1991
1991
Loc

Gyrodactylus pimelodellus

An, Jara & Cone 1991
1991