Geoplana piratininga, Ana Laura Almeida & Fernando P. L. Marques & Fernando Carbayo, 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 : 32-35

GEOPLANA PIRATININGA ALMEIDA & CARBAYO SP. NOV.

Geoplana vaginuloides: Marcus, 1952 , p. 76–77.

Material examined

Holotype MZUSP PL 2071 (field number F5134): Parque Jardim Previdência , São Paulo / SP, Brazil (23°34′48.7″S, 046°43′39.3″W). F. Carbayo et al., coll., 5 February 2006. Cephalic region: horizontal sections on four slides; ovarian region: horizontal sections on two slides; region behind ovaries: horizontal sections on ten slides; pharynx: sagittal sections on six slides; copulatory apparatus: sagittal sections on eight slides.

Paratype MZUSP PL 2060 (field number F0509): Parque Ecológico do Tietê, São Paulo/SP, Brazil (23°29′27.1″S, 046°31′0 1.6″W). F. Carbayo, coll., 27 May 2005. Pharynx and post-pharynx region: sagittal sections on six slides (incompletely mature).

Paratype MZUSP PL 666 (field number F1163): Parque Jardim Previdência, São Paulo/SP, Brazil (23°34′46.8″S, 046°43′39.0″W). O. M. Junior, coll., 17 June 2007. Pharynx: sagittal sections on 13 slides; copulatory apparatus: sagittal sections on seven slides (incompletely mature).

Distribution

Areas covered with secondary Atlantic forest and garden in the municipalities of São Paulo and Mongaguá, state of São Paulo, Brazil.

Etymology

The specific epithet is a Tupi (indigenous Brazilian tribe) word formerly referring to the city of São Paulo, where the species was collected.

Diagnosis

Dorsal colour pattern constituted by a median traffic red band, bounded on either side by a black stripe, externally to which is a white stripe, and in turn this is externally bordered by a black band, externally to which is a thin marginal white line. Dorsal and ventral insertions of penis papilla at the same transverse plane. Wall of female atrium not folded. Femaleto-male atrial length ratio, 2.0.

External aspect

Live animals 25 mm long and 4 mm wide. Body relatively short, with margins nearly parallel; anterior end rounded, posterior pointed. Dorsum strongly convex, ventral side slightly convex. Dorsal body surface constituted by a median traffic red band (1/3.5th of body width), passing into black part of cephalic region (one-sixth of body length) and of posterior tip, bounded on either side by a black stripe, externally to which is a white stripe (one-seventh), and in turn this is bordered externally by a black band (one-seventh), externally to which is a thin marginal white line ( Fig. 10A ). Ventral side whitish. After fixation, dorsal black colour faded, red passed into yelloworange and white into cream. Two types of eyes: a conical type, contouring only anterior end; and a cup-shaped type, spreading dorsally onto the black bands. Sensory pits simple invaginations, 25 μm deep, located ventromarginally in a single row from the very anterior end up to at least first one-fifth of body length. Relative position mouth-to-body length, 42.5%. Relative position gonoporeto-body length, 64%.

Internal morphology

Creeping sole ~85% of body width, as measured on horizontal or sagittal sections. 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 µm thick) arranged into bundles. Three parenchymal muscle layers present, all weakly developed: dorsal layer of decussate diagonal fibres, supraintestinal layer of transverse and longitudinal fibres, and subintestinal layer with transverse fibres. Additionally, longitudinal fibres surround intestine as a loose tube, the ventral fibres of which are mixed up with those of the subintestinal layer. Ventral nerve plate present.

Mouth situated at a distance from root of the pharynx equivalent to 50–65% of pharyngeal pocket length. Pharynx cylindrical, with dorsal insertion slightly posterior to ventral one ( Fig. 10B ). Oesophagus-to-pharynx ratio, 12%. Outer pharyngeal musculature consisting of a subepithelial layer (5 µm) of longitudinal muscle, followed by a layer (45 µm) of circular fibres, the innermost of which are intermingled with longitudinal ones. Inner pharynx musculature consisting of a thin subepithelial layer of longitudinal muscle, followed by a layer (40 µm) of circular fibres and an innermost layer (10 µm) of longitudinal fibres ( Fig. 10C ).

Testes dorsally located between supraintestinal parenchymal muscle layer and intestine; anteriormost testes at a distance from anterior end equivalent to 25.5% of body length; posteriormost follicles a little anterior to pharynx root. Penis bulb elongated, somewhat oval, extending from 0.3 mm anterior to penis papilla; from thereon the bulb extends ventrally, whereas dorsally it extends posteriorly for only short distance. The bulb consists of variously orientated packed muscle fibres. Diagonal fibres on the right side of the bulb run obliquely downwards to embrace ventrally the anterior portion of the female atrium. These fibres apparently mix with the subintestinal parenchymal musculature, but their anchor point could not be discerned. Sperm ducts run dorsally to the ovovitelline ducts. Sperm ducts bend medially behind insertions of penis papilla and penetrate penis bulb ventrolaterally. The ducts subsequently recurve to join and thus form the ejaculatory duct, which sinuously posteriad, then traverses the penis papilla to open at its tip. Distal portion of sperm ducts containing sperm, along their course both outside and inside penis bulb.

Sperm ducts lined with a cuboidal, ciliated epithelium and surrounded by a 6-µm-thick layer of circular muscles. Extrapapillar portion and anterior portion of intrapapillar section of ejaculatory duct lined with columnar ciliated epithelium, pierced by glands producing erythrophil fine granules. Remaining section of the ejaculatory duct also columnar and ciliated, pierced by numerous gland cells producing erythrophil granules. Entire ejaculatory duct surrounded by a layer of circular muscle, 35 µm thick around anterior portion, otherwise 10 µm thick ( Fig. 10D ). Diameter of muscular cylinder surrounding ejaculatory duct is equivalent of 3.5 times the diameter of this duct.

Penis papilla is long, horizontal and cylindrical along most of its length, with dorsal and ventral insertions at the same transverse plane ( Fig. 11A, B ). Total length of papilla equal to five times its greatest diameter, and completely filling both male and female atrium; papilla lined with a cuboidal epithelium, pierced by gland cells producing coarse erythrophil granules; glands producing cyanophil granules packed in space immediately beneath epithelium of the dorsal second third of penis papilla, so that subepithelial muscle fibres are separated from it ( Fig. 10D ). Penial subepithelial musculature consisting of dense 90-µm-thick layer of circular muscle, followed by a layer (25 µm thick) of longitudinal muscle.

Male atrium ample, not folded, lined with a low, non-ciliated epithelium, pierced by glands secreting erythrophil amorphous substance and underlain by a 15-µm-thick layer of circular muscles, followed by an inconspicuous layer of longitudinal fibres.

Ovaries incompletely developed, 500 µm in length along anteroposterior body axis, located above ventral nerve plate and situated at a distance from anterior end equivalent to ~20.5% of body length. Laterally to the female atrium, the oviducts curve medially and join to form a common glandular ovovitelline duct. This duct is as long as one-third of the female atrium length and communicates with the female genital duct, the latter being a funnel-shaped, anterodorsally orientated projection of the posterior region of the female atrium.

Female atrium funnel shaped and without folds, as long as two times the male atrium length ( Fig. 11B ); in its anterior portion it is lined with cuboidal epithelium, posteriorly with a 40-µm-high epithelium with stratified aspect; pierced by two types of glands producing cyanophil and xanthophil granules, respectively. Epithelium underlain by a 5- to 40-µm-thick layer of circular-to-decussate muscle fibres, followed by a 25-µm-thick layer of longitudinal fibres. Additionally, 4-µm-thick longitudinal fibres around these muscles constitute a kind of muscle coat.

Figures

Figure 10. Geoplana piratininga sp. nov. A, dorsal view of the live specimen MZUSP PL 2060; anterior to the left, ~32 mm in length. B, photomicrograph of a sagittal section of the pharynx of specimen MZUSP PL 2071. C, photomicrograph of the three muscle layers of the internal musculature of the pharynx in sagittal section of specimen MZUSP PL 2071. D, photomicrograph of dorsal epithelium of penis papilla and erythrophil glands located immediately beneath the epithelium of specimen MZUP PL 2071 in sagittal section.

Figure 11. Geoplana piratininga sp. nov. A, photomicrograph of a sagittal section of the copulatory apparatus of specimen MZUSP PL 2071. B, diagrammatic representation of the copulatory apparatus of specimen MZUSP PL 2071 from sagittal sections.