Dugesia milloti de Beauchamp 1952
Creators: name: Stocchino, Giacinta Angela
name: Sluys, Ronald
name: Solà, Eduard
name: Riutort, Marta
name: Manconi, Renata
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Tricladida
Dugesiidae
Dugesia
Dugesia milloti

description: Dugesia milloti de Beauchamp, 1952
Material examined
ZMA V.Pl. 787.1, stream of Roussette, Montagne d’Ambre, Madagascar (12°37 ʹ 0.00 ʹʹ S 49°8 ʹ 60.00 ʹʹ E), 17 September 1957, sagittal sections on nine slides.
Mf N F 217-c, Andrangolaoka, Madagascar (19°1 ʹ 60.00 ʹʹ S 47°55 ʹ 0.00 ʹʹ E), coll. F. Sikora (specimens registered at the Berlin Museum on 25 March 1892), sagittal sections on nine slides; Mf N F 217-a, ibid., sagittal sections on eight slides; Mf N F 217-b, ibid., sagittal sections on five slides.
Geographical distribution
Known from the following localities: (i) the type locality Morafenobé, forêt de Mahajeby, stream of Roussette, northwest Madagascar; (ii) Parc National de La Montagne d’Ambre, Diana Region, northern Madagascar; (iii) Andrangolaoka, Central High Plateau, east to Mantasoa Lake; (iv) Cascade de Mutsamudu, Anjouan, Comoro Islands (Fig. 1).
Comparative discussion
As de Vries (1988) based her redescription of D. milloti primarily on specimens from Montagne d’Ambre (in our material represented by specimen ZMA V.Pl. 787.1) her account still is basically correct, although she did not provide specific information on the testes and the position of the mouth opening. Examination of our material learned that the small testes are situated dorsally and that the follicles extend from a short distance behind the ovaries to the posterior end of the body. The ovaries are located at a short distance (~400 μm) behind the brain, i.e. at about one-ninth of the distance between the brain and the root of the pharynx. The mouth opening is located at about one-sixth of the distance between the hind wall of the pharyngeal pocket and the root of the pharynx.
Characteristic for D. milloti are the two annular atrial folds or valves, the posterior valve receiving a bundle of longitudinal muscles that extends posteriorly from the penis bulb (cf. de Vries 1988: figs 9, 10; Fig. 3). These annular atrial folds are much less clear in the old specimens from Andrangolaoka, which suffer from preservation and contraction artefacts (Figs 4, 5). However, in specimen MfN F217-a, folds in the atrium are still visible, presumably representing the most posterior valve—also receiving the longitudinal muscles from the penis bulb—as the anterior fold sits at the root of the penis papilla (Fig. 6).
As compared with the other long-eared species of Dugesia (see below), the copulatory apparatus of D. milloti is characterized by a slim, conical penis papilla and a large, valve-like diaphragm, the latter receiving the erythrophil secretion of penial glands that contributes to the formation of the spermatophore (de Vries 1988: figs 9, 10; Figs 5, 6).
description: Published as part of Stocchino, Giacinta Angela, Sluys, Ronald, Solà, Eduard, Riutort, Marta & Manconi, Renata, 2024, The long-eared freshwater planarians of Madagascar form a separate phylogenetic clade within the genus Dugesia (Platyhelminthes: Tricladida), with the description of two new species, pp. 1-29 in Zoological Journal of the Linnean Society (zlae 143) (zlae 143) 202 (4) on pages 8-9, DOI: 10.1093/zoolinnean/zlae143, http://zenodo.org/record/14811333