Choeradoplana gladismariae, 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 : 1169-1176

publication ID	https://doi.org/ 10.1080/00222933.2012.657699
DOI	https://doi.org/10.5281/zenodo.10536798
persistent identifier	https://treatment.plazi.org/id/743ED769-FFA3-BE03-70BB-09DBE5BBFA7D
treatment provided by	Felipe
scientific name	Choeradoplana gladismariae
status	sp. nov.

Treatment

Choeradoplana gladismariae View in CoL sp. nov.

( Figures 16–22 View Figure 16 View Figure 17 View Figure 18 View Figure 19 View Figure 20 View Figure 21 View Figure 22 ; Tables 5, 6)

Type material

Holotype. MZUSP PL 1003 : Parque Estadual Intervales, Ribeirão Grande / SP, Brazil, 24 ◦ 16 ′ 35 ′′ S, 48 ◦ 24 ′ 56 ′′ W, F. Carbayo et al., col., 12 December 2008. Cephalic region : transverse sections on four slides; anterior region 2 (ovaries): sagittal sections on five slides; anterior region 3: horizontal sections on four slides; pre-pharyngeal region: transverse sections on three slides. Pharynx and copulatory apparatus: sagittal sections on 10 slides. GoogleMaps

Paratype. MZUSP PL 1004 : ibid., 24 ◦ 16 ′ 35 ′′ S, 48 ◦ 24 ′ 56 ′′ W, F. Carbayo et al. col., 7 July 2009. Cephalic region : horizontal sections on two slides; anterior region 2: sagittal sections on three slides; pre-pharyngeal region: transverse sections on one slide. Pharynx and copulatory apparatus: sagittal sections on four slides GoogleMaps .

Type locality

Parque Estadual Intervales, Ribeirão Grande / SP, Brazil, covered with primary Atlantic Rainforest.

Etymology

Specific name from Gladis Maria Schmidt, Carbayo’s wife, to whom this species is dedicated.

Diagnosis

Choeradoplana species with a thin dark-brown mid-stripe and two para-median bands of brown spots on a pale yellowish dorsum; both dorsally and ventrally, the cutaneous muscle layer of longitudinal muscle is partially sunken into the parenchyma; prostatic vesicle wall bellows-like and pleated.

Description

Body relatively wide, with convex dorsum, rounded margins and slightly convex ventral side. Anterior end ventrally provided with pair of glandular cushions separated by longitudinal groove, and kept up and rolled backwards by the live worm. Posterior end pointed. Largest specimen (holotype) measured, when alive, up to 32 mm in length and 2 mm in width; after fixation, with cephalic region unrolled, 35 mm ( Table 5). Mouth 18.5 mm from anterior end, and gonopore 22.7 mm (holotype).

Dorsally, rolled anterior end excepted, ground colour yellowish with thin longitudinal dark brown mid-stripe (1 / 25 of body width) and two para-median bands (1 / 4 of body width) of brown specks, disposed as to create a marmorean aspect ( Figure 16 View Figure 16 ). In the rolled cephalic extremity, median line ends before the apex, and the bands are reduced to externalmost bold limits; the exposed ventral surface is greyish, especially on margins of median groove. In posterior extremity, median stripe and abruptly narrowed bands merge. Ventral side is whitish medianly, and faintly yellow marginally.

G, gonopore; L, length; M, mouth; W, width.

Eyes comprise one pigmented cup, 50–70 µm in diameter, roughly arranged as two or three marginal rows up to posterior end. Absent in very anterior tip. Without clear halos. Sensory pits, 20–30 µm deep, as a uniserial ventrolateral row, from little behind the anterior end through 11 mm (holotype).

Epidermis ciliated just over creeping sole. In cephalic end, rhabditogen cells open onto entire surface, but more densely through epithelium of glandular cushions. Their cellular bodies lay in parenchyma between subcutaneous nerve plexus and epithelium.

Cerebral ganglia 3 mm behind apex. Although not clearly delimited from ventral nerve plate, 80 µm thick; it is approximately 5 mm long and 130 µm thick (holotype).

Three usual geoplaninid cutaneous muscle layers present: one circular, two diagonal with decussate fibres, one longitudinal with fibres arranged into bundles ( Table 6). Dorsally, as well as ventrally, body margins excluded; longitudinal layer partially sunk into parenchyma. Dorsal sunken fibres gathered into well-delimited, compact bundles, 107 µm thick; ventral ones much less numerous, gathered into a layer (45 µm Lowest and highest number of muscle fibres per bundle are given in parenthesis.

CMI, cutaneous musculature thickness relative to body height at the pre-pharyngeal region. thick) with loose, smaller, ill-delimited bundles ( Figures 17–19 View Figure 17 View Figure 18 View Figure 19 ). In the cephalic region dorsal longitudinal sunken fibres are less apparent; direction of fibres in histological sections is not clearly discernible. CMI, 21.2–22.0%. Otherwise, arrangement of cutaneous muscle fibres in cephalic region as in C. iheringi (see Froehlich 1955; Carbayo and Leal-Zanchet 2003).

Parenchymal musculature: besides dorsoventral muscles, layer of dorsodiagonal fibres (20 µm thick, holotype) (followed by the sunken layer of longitudinal muscles mentioned above), the transverse supraintestinal (60 µm thick) and subintestinal (48 µm thick) fibres ( Figures 17 View Figure 17 , 18 View Figure 18 ), and, in cephalic region, a transverse subneural muscle layer (25 µm thick), between ventral nerve plate and retractor muscle. Arrangement of parenchymal muscle fibres in cephalic region as in type species ( Froehlich 1955; Carbayo and Leal-Zanchet 2003).

Mouth located in middle of pharyngeal pouch. Pharynx bell-shaped, with folded free margin ( Figure 20 View Figure 20 ). Dorsal insertion approximately at the same transverse level as mouth. Lining epithelium of pharyngeal pouch flat, non-ciliated, underlain by onefibre-thick layer of circular muscle fibres. Outer pharyngeal epithelium flat ciliated, with sunken nuclei. Underlain by a 5-µm-thick layer of longitudinal muscle fibres, followed by one with circular fibres (6 µm thick). Inner pharyngeal epithelium cubicto-flat, ciliated, followed by layer of circular fibres (45 µm thick) with interspersed longitudinal ones.

Testes located between supraintestinal parenchymal muscle layer and intestine, extending as a single-to-triple row from 1 mm anterior to each ovary (3.5 mm behind cerebral ganglia) up to level with dorsal pharyngeal insertion (holotype). Sperm ducts run immediately above subintestinal muscle layer, just dorsally to ovovitelline ducts. Near the copulatory complex, sperm ducts communicate with the paired extrabulbar, branches of prostatic vesicle. Prostatic branches penetrate into penial bulb, unite as a short tube that opens into the final, dilated portion of prostatic vesicle ( Figures 21 View Figure 21 , 22 View Figure 22 ). This portion has a complex structure, with pleated lateral walls, the whole organ reminiscent of a bellows. On each side of the vesicle, the pleats, disposed in a dorsoventral series, are oriented as to converge ectally, where they end leaving the ectal, final, portion of vesicular cavity free of pleats. Medianly the cavity, ample in sagittal plane but very narrow transversally, separates two lateral sets of pleats. Both sides of vesicle, between each pair of pleats in dorsoventral series, a bag, open to the median cavity, is formed. Ectally, vesicular cavity continues through male atrium. Lumen of atrium is narrow and its wall folded.

Branches and tubular portion of prostatic vesicle are clothed with a columnar ciliated epithelium, which is crossed by secretory cells containing fine erythrophil granules. In dilated portion, pleats are mostly lined with non-ciliated cubic epithelium; in rest of cavity wall it is ciliated. Regarding their secretions, pleats are clearly differentiated into two regions: a basal region, the most extensive, and a distal one. The former receives two types of glands, respectively: one, very abundant, with erythrophil granules, and the other, very scarce, with xanthophil granules; both types have their cellular bodies in parenchyma, anterior to copulatory complex. Distal region is very richly pierced by secretory cells containing fine highly erythrophil granules, whose cellular bodies lay below epithelium. A 12-µm-thick layer of circular muscle fibre underlies epithelium of pleats. Involving the whole dilated portion, a mass of glandular tissue is fully saturated with coarse granules of an erythrophil secretion. There are some interspersed muscle fibres. Male atrium lined with cubic-to-columnar epithelium, entally ciliated where glands discharge their cyanophil granular secretion. Ectally epithelium receives an erythrophil granular secretion. Male atrium coated with a layer of circular muscle fibres, 8 µm thick.

Ovaries roughly ellipsoid, 250 µm in diameter. Located immediately above ventral nerve plate, at 11 mm from anterior tip, and 4.5 mm behind cerebral ganglia (holotype). Ovovitelline ducts arise from external side of ovaries, and run backwards above ventral nerve plate. Behind gonopore they ascend laterally to female atrium, posteriorly and medianly inclined, then unite dorsally to atrium, and continue as common glandular ovovitelline duct. The latter runs backwards to communicate with vagina ( Figures 21 View Figure 21 , 22 View Figure 22 ). Short vagina arises dorsally from female atrium, and proceeds curved forward, then receives common glandular ovovitelline duct. Shell glands also open into distal portions of paired ovovitelline ducts. Female atrium is an ample cavity dorsoventrally dilated and laterally narrowed. It is two-thirds the length of male atrium.

Vagina and female atrium lined with columnar, non-ciliated epithelium, which receives two types of glands, with erythrophil and fine cyanophil secretions, respectively. It is underlain by a 6–10-µm-thick circular muscle layer.

Common muscular coat of the copulatory complex composed of a weak layer, 80–120 µm thick, of intermingled fibres.

Discussion

Among striped Choeradoplana species , only C. gladismariae and C. ehrenreichi have an odd number of three distinct longitudinal dark stripes on a clear ground. They differ, however, in that C. ehrenreichi has three equally wide stripes, whereas in C. gladismariae the lateral stripes are much wider than the median one. They are bands rather than stripes.

Regarding the internal morphology, C. gladismariae has an outstanding characteristic, unique for the genus, that is, the strong dorsal layer of insunk cutaneous longitudinal fibres. In the Choeradoplana species described up to now, a similar muscle arrangement occurs only ventrally, as is stated in Froehlich’s diagnosis of the genus ( Froehlich 1955). Besides Choeradoplana , three other Geoplaninae genera, the three monotypic, have been described with the cutaneous longitudinal musculature partially sunken into the parenchyma, namely Gusana, E.M. Froehlich, 1978 Liana E.M. Froehlich, 1978 and Supramontana Carbayo and Zanchet, 2003 . Only Gusana cruciata , the Chilean unique species of the genus, has the cutaneous longitudinal muscles partially sunken both dorsally and ventrally, like C. gladismariae . However, in G. cruciata , dorsal sunken muscle fibres do not gather into bundles but occur loosely in the parenchyma between the subcutaneous nerve plexus and the ventral nerve plate (E.M. Froehlich 1978). Choeradoplana and Gusana , as well as Liana and Supramontana , are distinct genera through the morphology of their cephalic extremities.

Choeradoplana emended diagnosis

As a result of the present study the diagnosis of Choeradoplana must be emended on some points, as follows: Geoplaninae of elongated subcylindrical body. Cephalic region with two glandular cushions, ventrally separated by a longitudinal groove; kept rolled up and backwards in live worms. Eyes and sensory pits absent in the apex. Broad creeping sole, more than one-third of body width. Strong cutaneous longitudinal muscles partially sunken into the parenchyma, exclusively ventrally or, more rarely, ventrally and dorsally too. Anteriorly all sunken ventral longitudinal fibres concentrated medianly, constituting the retractor unroller of the cephalic extremity. Common glandular ovovitelline duct approaching vagina dorsally from anterior direction, more rarely approaching behind the female atrium from the ventral direction.