Choeradoplana bocaina, Carbayo & Froehlich, 2012

Carbayo, Fernando & Froehlich, Eudóxia Maria, 2012, Three new Brazilian species of the land planarian Choeradoplana (Platyhelminthes: Tricladida: Geoplaninae), and an emendation of the genus, Journal of Natural History 46 (19 - 20), pp. 1153-1177 : 1155-1161

publication ID	https://doi.org/ 10.1080/00222933.2012.657699
DOI	https://doi.org/10.5281/zenodo.10536794
persistent identifier	https://treatment.plazi.org/id/743ED769-FFB5-BE11-7357-099BE71DFEB1
treatment provided by	Felipe
scientific name	Choeradoplana bocaina
status	sp. nov.

Treatment

Choeradoplana bocaina View in CoL sp. nov.

( Figures 1–8 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 View Figure 8 ; Tables 1, 2)

Type material

Holotype. MZUSP PL 997 : Parque Nacional da Serra da Bocaina , São José do Barreiro / SP, Brazil, c. 22 ◦ 45 ′ 08 ′′ S, 44 ◦ 37 ′ 19 ′′ W, F. Carbayo et al. col., 8 September 2008. Cephalic region: sagittal sections on 10 slides; pre-pharyngeal region: transverse sections on three slides; pharynx: sagittal sections on 13 slides; copulatory apparatus: sagittal sections on six slides. GoogleMaps

Paratypes. MZUSP PL 998 : ibid., 22 ◦ 45 ′ 08 ′′ S, 44 ◦ 37 ′ 19 ′′ W, F. Carbayo et al. col., 7 September 2008. Anterior region 2: horizontal sections on seven slides; anterior region 3: transverse sections on four slides; pharynx plus copulatory apparatus: sagittal sections on 14 slides GoogleMaps ; MZUSP PL 999 : ibid., 22 ◦ 45 ′ 08 ′′ S, 44 ◦ 37’19 ′′ W, F. Carbayo et al., col., 10 February 2008. Cephalic region : transverse sections on five slides; pharynx and copulatory apparatus: sagittal sections on five slides GoogleMaps .

Type locality

Parque Nacional da Serra da Bocaina, São José do Barreiro / SP, Brazil, covered with primary Atlantic Rainforest.

Etymology

The specific epithet refers to the Tupi-Guarani (Indigenous Brazilian tribe) name of the National Park where the type material was collected.

Diagnosis

Choeradoplana species with small dark pigmented spots dispersed on the dorsum; pharynx bell-shaped; extra-bulbar portion of prostatic vesicle proximally two-forked, dish-shaped distally; posterior section of the female atrium narrow.

Description

The largest live specimen (paratype MZUSP PL 998) measures up to 48 mm in length and 4 mm in width (see Table 1 for size of fixed specimens). The body is slender ( Figure 1 View Figure 1 ). Dorsum highly convex in cross-section; body margins rounded; ventral side slightly convex. The cephalic region, which bears the glandular cushions typical of the genus, is kept rolled up in the living worm when creeping and resting. The posterior end is pointed. The creeping sole is as wide as 74% of body width at the pre-pharyngeal region. Mouth 19.5 mm from anterior end, gonopore at 23 mm (holotype).

Ground colour of dorsum is yellowish-brown; ventral side pale brown in the cephalic region, cream in rest of the body. Dorsum of holotype and of paratype MZUSP PL 999 with dark brownish spots of different size, more densely concentrated paramedianly, so delineating an irregular longitudinal stripe on each side. In the G, gonopore; L, length; M, mouth; W, width. paratype MZUSP PL 998 the dorsal region is almost completely covered by a dense web of brown pigment. There is medianly a darker longitudinal stripe of brownish pigment.

Eyes formed by one pigmented cup, 40–45 µm in diameter. No clear halos around them. Eyes absent in the first 3.3 mm of body (paratype MZUSP PL 999). Posteriorly they are irregularly arranged in a marginal row of three or four eyes throughout body length. At pre-pharyngeal region the eyes spread onto the back in a band 12% of body width. Sensory pits distributed ventro-laterally in a uniserial row from 1.8 mm behind the anterior end to near ovaries (paratype MZUSP PL 999).

Epidermis ciliated only in creeping sole. Contrary to what occurs along body, in cephalic region the bodies of the rhabditogen cells that discharge through the glandular cushions are located between retractor muscle and ventral epidermis.

Ventral nerve plate 70 µm in thickness; cerebral ganglia not visible in available horizontal sections.

The cutaneous musculature comprises the three typical layers of Geoplaninae ( Table 2): a subepithelial circular layer followed by two diagonal with decussate fibres, and then a strongly developed longitudinal layer with fibres arranged in bundles ( Figures 2 View Figure 2 , 3 View Figure 3 ). As characteristic of the genus, some of the muscle fibres of ventral Lowest and highest number of muscle fibres per bundle are given in parentheses.

CMI, cutaneous musculature thickness relative to body height at the pre-pharyngeal region. longitudinal layer are sunk into parenchyma. Medianly, in paratype MZUSP PL 998 a few dorsal longitudinal fibres are also sunk into parenchyma and intermingled with those of parenchymal dorsal layer of diagonal decussate fibres ( Figure 2 View Figure 2 ). CMI, 20.0–28.7%. In cephalic region, ventral longitudinal layer is completely sunk into parenchyma, constituting cephalic retractor muscle, as described for C. iheringi and three other species by Froehlich (1955).

The three usual parenchymal muscle layers are present throughout the body: a well-developed dorsal layer of diagonal decussate fibres (38 µm thick, holotype), a transverse supraintestinal layer (30–35 µm), a transverse subintestinal layer (20–25 µm). In cephalic region there is an additional layer of transverse fibres, between ventral nerve plate and retractor muscle: the subneural muscle layer.

Mouth lying in middle of pharyngeal pouch ( Figure 4 View Figure 4 ). Pharynx bell-shaped, having dorsal insertion approximately at mouth level. Epithelium lining pharyngeal pocket squamous, non-ciliated, surrounded by a thin circular subepithelial layer. Outer and inner pharyngeal epithelia flat, ciliated. Outer one underlain by a one-fibre thick layer of longitudinal muscle fibres followed by a layer of circular fibres (10 µm); inner epithelium underlain by a layer of circular fibres (40 µm) with interspersed longitudinal fibres.

Testes located under supraintestinal transverse muscle layer, partially placed between the intestinal diverticula ( Figure 2 View Figure 2 ). They extend from level of ovaries to root of pharynx (paratype MZUSP PL 998). Sperm ducts run immediately above subintestinal muscle layer, slightly dorsal and lateral to ovovitelline ducts. Near prostatic vesicle, they curve dorso-anteriorly to communicate with the two vertical, dilated branches of extra-bulbar portion of vesicle ( Figures 5–8 View Figure 5 View Figure 6 View Figure 7 View Figure 8 ). The latter is dish-shaped, diagonally inclined, and receives the branches through its anterior ventral face. It continues inside penial bulb as an ample, almost horizontal, tubular portion. Its opening into male atrium is narrow in holotype and wide in paratype MZUSP PL 998. Male atrium has some small folds entally, and a large ventral fold ectally. There is no ejaculatory duct as a differentiated portion.

Whole prostatic vesicle lined with columnar, ciliated epithelium. Extrabulbar portion receives abundant granulous erythrophil secretion. Additionally, receives gross granular xanthophil secretion around openings of branches. Intrabulbar portion pierced by gland cells, each containing a different type of secretion. They are distributed into rings, from proximal to distal end of vesicle, as follows: gross xanthophil granules, fine erythrophil granules mixed with fine xanthophil ones, and very fine erythrophil granules. Extrabulbar portion surrounded by interwoven muscle fibres, and intrabulbar portion by a muscular layer of circular fibres interspersed with longitudinal ones. The male atrium lined with cuboidal to columnar epithelium, non-ciliated, apically xanthophil, and crossed by cells containing erythrophil granular secretions. Male atrium is clothed with a dense layer of circular muscle fibres (25 µm thick) followed by one of longitudinal fibres (50–80 µm).

Ovaries rounded, c.300 µm in diameter, placed 11 mm from anterior end, above the ventral nerve plate (paratype MZUSP PL 998). Ovovitelline ducts emerge from dorsoexternal aspect. Laterally to female atrium, they rise posteriorly and are medianly inclined, then unite dorsally, in the sagittal plane, to the common glandular ovovitelline duct ( Figures 5 View Figure 5 , 6 View Figure 6 , 8 View Figure 8 ). They receive shell glands into distal portion. Common glandular ovovitelline duct is short, and directed downwards; continuous with vagina, an upward diverticle of female atrium. In the holotype female atrium is dilated anteriorly and abruptly narrowed posteriorly; in paratype MZUSP PL 998, whole atrium is a narrow cavity. Female atrium is as long as one-third to half of male atrium. At level of gonopore, an irregular dorsal fold separates male and female atria.

Vagina is lined with a columnar to cuboidal ciliated epithelium, crossed by scarce gland cells containing granular erythrophil secretion. Coated with thin layer of circular muscle fibres. Female atrium lined with columnar, non-ciliated epithelium, apically xanthophil, and penetrated by scarce cells containing granular erythrophil secretion. It is surrounded by a thin longitudinal muscle layer followed by a circular one (12 µm). Common muscular coat formed, especially in anterior portion, by a very dense layer, 120 µm thick, of decussate fibres.

Discussion

The genus Choeradoplana currently contains six species: C. ehrenreichi von Graff, 1899 , C. iheringi , C. langi von Graff, 1899 , C. bilix Marcus, 1951 , C. catua Froehlich, 1955 and C. marthae Froehlich, 1955 . Regarding the colour pattern, all of them, except for Choeradoplana iheringi , differ from C. bocaina in that they have sharp dark longitudinal lines or bands on a clear ground, instead of the dark speckles of variable size and density, as in C. bocaina . In C. iheringi , the back is homogeneously mottled with minute brown spots.

Regarding the internal morphology, C. bocaina does not have any peculiar outstanding characteristics. However, morphological details, or the combination of features of the copulatory complex as well as those of the pharynx, do not allow its identification with any of the previously described species. Choeradoplana catua , a species with dark lines along the body, is the most similar as regards the general anatomy, but its prostatic vesicle is completely intrabulbar, contrasting with that of C. bocaina , which is partially extrabulbar. In addition, in C. catua , the dorsal insertion of the pharynx and mouth are at the same transverse level, whereas in C. bocaina , dorsal insertion is anterior to the mouth.