Hippocrepis fuelleborni Travassos & Vogelsong 1930
Creators: name: Martins, Natalia Beatriz Guerreiro
name: Robles, María Del Rosario
name: Canova, Victoria
name: Diaz, Julia Inés
name: Callejón, Rocío
name: Balcazar, Dario
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Digenea
Plagiorchiida
Notocotylidae
Hippocrepis
Hippocrepis fuelleborni

description: Hippocrepis fuelleborni Travassos & Vogelsong, 1930
Description (based on 22 specimens): body flat, elongated (Figs. 2A–B, 3A), 2.81 ± 0.44 (1.68–3.52) long by 0.77 ± 0.13 (0.45–1.04) wide. Lateral projections on each side of the oral sucker (Figs. 2B, 3C). Tegument covered with spines (Fig. 3E–F), smooth oral sucker edges, and covered with small spines from the oral sucker to the genital pore (Fig. 3C–D). Ventral surface concave and provided with numerous longitudinal rows of ventral papillae arranged irregularly, extending from the middle zone of the cirrus sac to posterior extremity (Figs. 2B, 3A–B, 4A), with a diameter of 51.97 ± 6.34 (43.02–57.81) µm. Ventral sucker absent. Oral sucker subterminal, 0.28 ± 0.04 (0.21–0.34) long by 0.22 ± 0.003 (0.17–0.32) wide. Pharynx absent; oesophagus 0.05 ± 0.01 (0.04–0.07). Caeca with lateral diverticula in its entire extension, bordering vitelline follicles, fuse posteriorly to the ovary passing between testes, up to level of their posterior border (Figs. 2A, 4C). Testes irregularly lobed, oblique, posterior to caecal union, right testis 0.24 ± 0.05 (0.15–0.34) long by 0.19 ± 0.04 (0.13–0.27) wide, left testis 0.23 ± 0.05 (0.15–0.32) long by 0.19 ± 0.05 (0.13–0.28) wide. Cirrus sac median, elongate 0.68 ± 0.08 (0.55–0.88) long, containing cirrus and internal seminal vesicle (Fig. 2C). Cirrus not everted, with small spines (Fig. 4B). Genital pore median, posterior to caecal bifurcation. Ovary median, pretesticular, transversally elongated (Fig. 2D), 0.13 ± 0.03 (0.10–0.19) long by 0.24 ± 0.06 (0.10–0.36) wide. Vitelline follicles arranged in longitudinal series, extracaecal and pre-ovarian, ending close to testes, 0.60 ± 0.07 (0.50–0.70) long. Uterus transverse coils located in intercaecal space. Eggs oval, without polar filaments (Figs. 2E, 4D), 26.38 ± 11.94 (20.70–69.15) µm long by 8.54 ± 1.09 (6.72–10.25) µm wide.
Taxonomic summary
New host: Holochilus brasiliensis (Desmarest 1819)
Host specimen deposited: CNP 6596
Site of infection: caecum.
New locality: Laguna de Chascomús (35°32'38.52"S; 58° 4'46.47"W), Buenos Aires province, Argentina.
Deposited specimens: a total of three voucher specimens (no. 8043) were deposited at MLP-He.
Comments: The specimens belong to the genus Hippocrepis by lateral projection present on either side of the oral sucker and caeca united to form a common caecum posterior to the ovary (Barton & Blair 2005).
Specimens studied here can be easily distinguished from Hi. myocastoris by the presence of ventral papillae, from Hi. hippocrepis by the distribution of vitelline follicles, and from Hi. myocastoris and Hi. hippocrepis by the asymmetrical position of the testes and eggs without polar filaments (Flores et al. 2007; Rocha et al. 2012).
The specimens collected from Ho. brasiliensis in this study present characters consistent with Hi. fuelleborni, a parasite of M. coypus: presence of ventral glands, the asymmetrical position of the testes, the distribution of vitellaria, and the eggs lacking polar filaments. However, we observed metric differences such as a smaller body size (maximum length 2.81 vs. 6.09), smaller cirrus sac (0.68 x 0.09 vs. 1.42 x 0.21), smaller testes (RT: 0.24 x 0.19, LT: 0.23 x 0.19 vs. 0.59 x 0.48), smaller ovary (0.24 x 0.13 vs. 0.40 x 0.31), and smaller eggs (0.026 x 0.001 vs. 0.023 x 0.009). Table 1 contains measurements of specimens under study and those parasitizing M. coypus from Uruguay, which are generally larger.
description: Published as part of Martins, Natalia Beatriz Guerreiro, Robles, María Del Rosario, Canova, Victoria, Diaz, Julia Inés, Callejón, Rocío & Balcazar, Dario, 2024, Hippocrepis fuelleborni (Digenea: Notocotylidae) from Argentina, morphological molecular and phylogenetic studies, pp. 225-240 in Zootaxa 5481 (2) on page 230, DOI: 10.11646/zootaxa.5481.2.3, http://zenodo.org/record/12749559