Geoplana iporanga, 2019

Ana Laura Almeida, Fernando P. L. Marques & Fernando Carbayo, 2019, ‘ Endless forms most beautiful’: taxonomic revision of the planarian Geoplana vaginuloides (Darwin, 1844) and discovery of numerous congeners (Platyhelminthes: Tricladida), Zoological Journal of the Linnean Society 185, pp. 1-65 : 49-54

GEOPLANA IPORANGA ALMEIDA & CARBAYO SP. NOV.

Material examined

All specimens were collected in Parque Estadual de Intervales, Ribeirão Grande / SP, Brazil (24°16′0 9.8″S, 0 4 8° 2 4 ′ 1 9.7 ″W). F. Carbayo et al., coll., 1 3 December 2008.

Holotype MZUSP PL 2065 (field number F3166): Ovarian region: sagittal sections on 17 slides; prepharyngeal region: transverse sections on seven slides; pharynx: sagittal sections on 11 slides; male genital atrium: sagittal sections on 21 slides; female genital atrium: sagittal sections on nine slides.

Paratype MZUSP PL 2064 (field number F3132) (immature): Cephalic region: horizontal sections on three slides; pharynx and copulatory apparatus: sagittal sections on 12 slides.

Distribution

Areas covered with Atlantic forest in Parque Estadual de Intervales, Ribeirão Grande, state of São Paulo, Brazil.

Etymology

The specific epithet is the name of another locality within the conservation area from where the species was collected.

Diagnosis

Dorsal colour pattern constituted by a median melon yellow band, bounded on either side by a black band, externally to which is a white band divided longitudinally in half by a black line. Penis bulb extending anteriorly 2 mm from penis papilla. Sperm ducts join inside penis papilla. Diameter of muscular cylinder around ejaculatory duct equivalent to ten times the diameter of this duct.

External aspect

Live animals ~50 mm long and 4 mm wide. Body margins nearly parallel; anterior end rounded, posterior pointed. Dorsum and ventral side slightly convex. Dorsal body surface constituted by a median melon yellow band (one-fifth of body width) that grades into black of cephalic region (one-tenth of body length), bounded on either side by a black band (one-quarter), externally to which is a white band (one-fifth) that is longitudinally divided into half by a black line fading towards rear end ( Fig. 20A ). Ventral surface white, with blackish margins. The dorsal colours of preserved specimens became slightly paler. Two types of eyes: a conical type, in a single row around anterior tip; and a cup-shaped type, spreading onto dorsum and reaching the black bands from immediately behind anterior end to the rear end. Sensory pits simple invaginations, 45 μm deep, located ventromarginally in a single row, from the very anterior end up to at least first one-quarter of body length. Relative position mouth-to-body length, 52%. Relative position gonopore-to-body length, 67%.

Internal morphology

Creeping sole 81% of body width. Glandular margin absent. Three typical geoplaninid cutaneous muscle layers present, being as thick as 5% of body height. Muscle fibres of the longitudinal, innermost layer (25–30 µm thick) arranged into bundles with 20–40 fibres each. Three parenchymal muscle layers present: dorsal layer of decussate diagonal fibres, supraintestinal layer of transverse and longitudinal fibres, and subintestinal layer with transverse and longitudinal fibres. Longitudinal fibres around intestine constituting a loose tube whose fibres mix with transverse ones. Ventral nerve plate present.

Mouth situated at a distance from root of the pharynx equivalent to 37–39% of pharyngeal pocket length. Pharynx cylindrical, dorsal insertion slightly posterior. Oesophagus-to-pharynx ratio, 12% ( Fig. 20B ). Outer pharyngeal musculature consisting of a subepithelial layer (7 µm) of longitudinal muscle, followed by a layer (55 µm) of intermingled circular and longitudinal muscle fibres. Inner pharynx musculature consisting of a thin subepithelial layer of longitudinal muscle, followed by a layer (110 µm) of circular fibres and an innermost layer (40 µm) of longitudinal fibres.

Testes located dorsally between supraintestinal parenchymal muscle layer and intestine; anteriormost testes at a distance from anterior end equivalent to 22% of body length; posteriormost follicles slightly anterior to root of pharynx. Penis bulb elongated, extending from 2 mm anterior to penis papilla to the level of the gonopore region; very strongly developed, mainly dorsally to male atrium. Penis bulb consists of tightly packed muscle fibres; fibres variously orientated proximally, and diagonally orientated distally. Distal fibres on the right side run obliquely downwards to embrace ventrally the anterior portion of the female atrium; these fibres seem to join fibres of the subintestinal parenchymal muscle layer, thus forming bundles; their anchor points could not be discerned.

Sperm ducts run dorsally to the ovovitelline ducts. Shortly before attaining the level of penial insertion, sperm ducts bend medially and ventrolaterally penetrate the bulb. The ducts subsequently run posteriorly, penetrate penis papilla and join to form the ejaculatory duct; this traverses the central region of penis papilla to open, presumably, at its tip, but this tip is missing. Sperm present in distal portion of sperm ducts, along their course both outside and inside penis bulb and penis papilla. Sperm ducts lined with a cuboidal, ciliated epithelium and surrounded by a 10-µm-thick layer of circular muscles. Ejaculatory duct lined with cuboidal, ciliated epithelium containing fine cyanophil granules, and surrounded by layer of circular muscles, tending to decussate towards tip of penis; layer with a maximal thickness of 140 µm on mid papilla, and constituting a muscular cylinder with a diameter equivalent to ten times the diameter of this duct ( Fig. 20C ).

Penis papilla horizontal and cylindrical along most of its length, with dorsal and ventral insertions at the same transverse plane ( Fig. 21A, B ). Papilla occupies entire male atrium and most of female atrium. Total length of papilla equal to six times its greatest diameter. Penis papilla covered with a low epithelium pierced by two types of gland cells, producing erythrophil and cyanophil granules, respectively. A moderate space, 10 µm thick, immediately beneath mid-dorsal epithelium of papilla packed by necks of latter gland type ( Fig. 20C ). Subepithelial musculature consisting of dense layer of circular muscle, tending to decussate distally, 200 µm thick dorsally, 100 µm thick ventrally, followed by a 10-µm-thick layer of longitudinal muscle. Stroma rich in diagonal fibres, especially distally. Male atrium ample, not folded, lined with a cuboidal epithelium, underlain by a 12-µm-thick layer of circular muscles, followed by a thin layer of longitudinal fibres.

Ovaries oval shaped, ~200 µm in anteroposterior diameter, situated at a distance from anterior end equivalent to one-quarter of body length. Laterally to female atrium, the oviducts curve medially and join to form the common glandular ovovitelline duct. Common glandular ovovitelline duct as long as one-third of female atrium length, and communicating with posterior portion of female atrium, the latter being 200 µm long and curved towards dorsal body surface.

Female atrium without folds, as long as three times that of male atrium ( Fig. 21B ). The very short posterior portion (200 µm in length) of the female atrium is lined with a 25-µm-high stratified-like, non-ciliated epithelium, which is surrounded by a 40-µm-thick layer of very thin muscle fibres. Otherwise, the female atrium is lined with cuboidal epithelium and pierced by gland cells producing cyanophil granules. Epithelium of female atrium and that of female genital duct are surrounded by 5- to 20-µm-thick layer of circular-todecussate muscle fibres, followed by a 5- to 55-µmthick layer of longitudinal fibres.

GEOPLANA PULCHELLA SCHULTZE & MÜLLER, 1857

FIGS 22 AND 23

Geoplana pulchella Schultze & Müller, 1857 : p. 25; Froehlich, 1955b, p. 189–190; du Bois-Reymond Marcus, 1951, p. 234–235 (misidentification).

Material examined

MZUSP PL 1068 (field number F3249): Parque Estadual da Serra do Tabuleiro, Paulo Lopes/SC, Brazil (27°58′53.0″S, 048°44′53.0″W). F. Carbayo, et al., coll., 14 January 2009. Cephalic region: transverse sections on 11 slides; ovarian region: horizontal sections on six slides; region behind ovaries: sagittal section on nine slides; pre-pharyngeal region: sagittal sections on ten slides; pharynx: sagittal sections on 11 slides; copulatory apparatus: sagittal sections on 11 slides.

MZUSP PL 2075 (field number F6528): RPPN Vale das Pedras, Alfredo Wagner/SC, Brazil (27°37′0 1.0″S,

049°20′52.0″W). A. L. Almeida et al., coll., 16 January 2015. Cephalic region: horizontal sections on four slides; ovarian region: horizontal sections on five slides; pre-pharyngeal region: transverse sections on four slides; pharynx: sagittal sections on four slides; copulatory apparatus: sagittal sections on nine slides.

MZUSP PL 2076 (field number F6544): RPPN Vale das Pedras, Alfredo Wagner/SC, Brazil (27°37′0 1.1″S, 049°20′53.3″W). A. L. Almeida et al., coll., 18 January 2015. Cephalic region: horizontal sections on five slides; region behind ovaries: horizontal sections on four slides; pre-pharyngeal region: transverse sections on seven slides; pharynx: sagittal sections on five slides; copulatory apparatus: sagittal sections on seven slides.

Note

We could not confirm identification of a specimen studied by Froehlich (1955b); see Supporting Information ( Table S1).

Distribution

Areas covered with Atlantic forest in municipalities of Blumenau, Paulo Lopes, Alfredo Wagner, Eastern part of Santa Catarina state, South Brazil.

Diagnosis

Anterior third of dorsal body pure orange; remaining dorsal side constituted by a median light grey band, bordered on either side by a black band; entire dorsum sprinkled with conspicuous whitish specks. Penis bulb extending anteriorly 1 mm from penis papilla. Papilla as long as seven to nine times its diameter and with a very thin tip. A conspicuous mass of very thin circular muscle fibres around posterior section of female atrium.

External aspect

Live animal 30 mm long and 3 mm wide when extended. Body elongated, margins nearly parallel; anterior end rounded, posterior pointed. Dorsum strongly convex, ventral side slightly convex. Anterior third of dorsal body surface pure orange; remaining two-thirds with a median light grey wide band (one-third), bordered on either side by a black band (one-third), with the exception of the very anterior end; entire dorsum sprinkled with conspicuous whitish specks ( Fig. 22A ). Anterior third of ventral body surface traffic white; rest of ventral surface squirrel grey. The dorsal colours of preserved specimens became slightly paler. Two types of eyes: a conical type, 80 µm high and 35 µm wide; and a cup-shaped type, 35 µm in diameter. The former contour the anterior third of the body. Cup-shaped type eyes in lateral bands, approximately one-third of body width. Sensory pits simple invaginations, 30 μm deep, located ventromarginally in a single row, from the very anterior end up to the pre-pharyngeal region. Relative position mouth-to-body length, 53%. Relative position gonopore-to-body length, 67%.

Internal morphology

Creeping sole 85% of body width. Glandular margin absent. Three typical geoplaninid cutaneous muscle layers present, being as thick as 5% of body height. Muscle fibres of the longitudinal, innermost layer (20 µm thick) arranged into bundles with 17–21 fibres each. Three parenchymal muscle layers present: dorsal layer of decussate diagonal fibres, supraintestinal layer of transverse and longitudinal fibres, and a subintestinal layer with transverse and longitudinal fibres. Ventral nerve plate present.

Mouth situated at a distance from root of the pharynx equivalent to 51% of pharyngeal pocket length. Pharynx cylindrical. Oesophagus-to-pharynx ratio, 22% ( Fig. 22B ). Outer pharyngeal musculature consisting of a subepithelial layer (5 µm) of longitudinal muscle, followed by a layer (50 µm) of intermingled circular and longitudinal muscle fibres. Inner pharynx musculature consisting of a thin subepithelial layer of longitudinal muscle, followed by a layer (65 µm) of circular fibres and an innermost layer (20 µm) of longitudinal fibres.

Testes dorsally located between supraintestinal parenchymal muscle layer and intestine; anteriormost testes at a distance from anterior end equivalent to 27% of body length; posteriormost follicles a little anterior to the root of the pharynx. Penis bulb elongated, extending from 1 mm anterior to penis papilla to level of gonopore region ( Fig. 22C, D ); strongly developed, consisting of tightly packed muscle fibres variously orientated proximally, whereas diagonally orientated distally. Penis bulb more developed dorsally to male atrium than ventrally. Oblique muscular ring embraces dorsodistal portion of male atrium and anteroventral portion of female atrium; some fibres detach from the ring and continue downwards to ventral epidermis behind gonopore region ( Fig. 23A ). Sperm ducts run dorsolaterally to the ovovitelline ducts. Laterally to penis bulb, sperm ducts bend anteriorly and medially and then ventrolaterally penetrate the bulb. The ducts subsequently join to form an unpaired duct that continues as the ejaculatory duct near the root of the penis papilla, and traverses its central region to open at its tip. Sperm present in distal portion of sperm ducts, along their course both outside and inside penis bulb. Sperm ducts lined with a cuboidal, ciliated epithelium and surrounded by a 7- to 10-µm-thick layer of circular muscles. Ejaculatory duct lined with tall, ciliated epithelium, pierced by conspicuous and numerous gland cells producing erythrophil granules. It is surrounded by a layer of circular muscles, tending to decussate towards penis tip; the layer has maximal thickness of 75 µm in the posterior half of the papilla, constituting a muscular cylinder with a diameter equivalent to four times the diameter of this duct.

Penis papilla long, horizontal and cylindrical along most of its length, with dorsal and ventral insertions at the same transverse plane; the very tip of this papilla is thin and long. This papilla occupies the entire male atrium and most of the female atrium. Total length of papilla equal to seven to nine times its greatest diameter. The papilla is covered with a cuboidal, non-ciliated epithelium, pierced by gland cells producing erythrophil granules; glands progressively more densely distributed towards the distal portion of the penis papilla. Subepithelial musculature consisting of dense 90-µmthick layer of circular muscle, tending to decussate distally, followed by a single layer of longitudinal muscle. Stroma of papilla traversed by numerous diagonal muscle fibres, especially distally. Male atrium ample, not folded; lined with a low, non-ciliated epithelium, and underlain by a 5-µm-thick layer of circular muscles, followed by an inconspicuous layer of longitudinal fibres.

Ovaries oval shaped, 260 µm in diameter in anterior–posterior axis, and situated at a distance from anterior end equivalent to one-quarter of body length. Ovovitelline ducts emerge from dorsolateral wall of ovaries. Laterally to female atrium, the oviducts curve medially and join to form common glandular ovovitelline duct. Common glandular ovovitelline duct as long as half of female atrium length, and communicating with female genital duct; this duct is a projection of the dorsoposterior region of thefemale atrium and is lined with a 25-µm-tall stratified-like, ciliated epithelium, with an erythrophil-free surface. A cyanophil fibrillar mass 10–20 µm thick is present immediately underneath this epithelium, with very thin circular filaments (<1 µm); it might be of glandular nature, albeit their circular arrangement resembles that of muscle fibres ( Fig. 23B ).

Female atrium without folds ( Fig. 22C, D ), twice as long as the male atrium, and lined with a cuboidal epithelium. This epithelium and that of female genital duct surrounded by 5- to 20-µm-thick layer of circularto-decussate muscle fibres, followed by a 5- to 55-µmthick layer of longitudinal fibres.

Figures

Figure 20. Geoplana iporanga Almeida & Carbayo sp. nov. Specimen MZUSP PL 2065. A, dorsal view of the live specimen, ~53 mm in length. B, photomicrograph of a sagittal section of the pharynx. C, mid-portion of penis papilla, with the ejaculatory duct and its surrounding muscle.

Figure 21. Geoplana iporanga Almeida & Carbayo sp. nov. Sagittal views of copulatory apparatus of specimen MZUSP PL 2065. A, microphotograph. B, diagrammatic representation.

Figure 22. Geoplana pulchella Schultze & Müller, 1857. A, dorsal view of the living specimen MZUSP PL 1068, 38 mm in length. B, photomicrograph of a sagittal section of the pharynx of specimen MZUSP PL 1068. C, photomicrograph of a sagittal section of the copulatory apparatus of specimen MZUSP PL 2076. D, diagrammatic representation of the copulatory apparatus from sagittal sections of specimen MZUSP PL 2076.

Figure 23. Geoplana pulchella Schultze & Müller, 1857. Photomicrographs of sagittal sections of specimen MZUSP PL 1068. A, fibres seemingly derived from penis bulb running downwards to ventral epidermis behind gonopore region. B, female genital duct and surrounding layer of very thin muscle fibres.