Geoplana chita, FROEHLICH, 1956

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 : 54-56

GEOPLANA CHITA FROEHLICH, 1956

FIG. 24

Geoplana chita – Froehlich, 1956b [in part].

Material examined

Original type material (from EMF collection): MZUSP PL 2092 (field number Specimen A): Curitiba / PR, Brazil. Froehlich, 21 November 1952. Copulatory apparatus: sagittal sections on two slides .

MZUSP PL 2093 (field number Specimen B): Curitiba/ PR, Brazil. E. M. Froehlich coll., 21 November 1952. Copulatory apparatus: sagittal sections on four slides. Specimen A or B: pre-pharyngeal region: transverse sections on two slides; pharynx: sagittal sections on one slide.

Other specimens: MZUSP PL 2084 (field number F6993): Morretes/PR, Brazil. E. M. Froehlich et al., coll., 17 June 1953. Pharynx and copulatory apparatus: sagittal sections on nine slides.

Additional material: MZUSP PL 2086 (field number F6995): Morretes/PR, Brazil. Magno C. Segalla, coll., 1 November 1987. Pharynx and copulatory apparatus: sagittal sections on 37 slides.

MZUSP PL 715 (field number F1710) (imature): Morretes/PR, Brazil (25°28′10.6″S, 048°48′49.5″W). F. Carbayo et al., coll., 13 January 2008. Pre-pharyngeal region: transverse sections on three slides; pharynx: sagittal sections on five slides; region behind pharynx: sagittal sections on four slides.

MZUSP PL 716 (field number F1730) (incompletely mature): Morretes/ PR, Brazil (2 5°2 8′ 1 0. 6″ S, 048°48′49.5″W). F. Carbayo et al., coll., 13 January 2008. Cephalic region: horizontal sections on four slides; pharynx and copulatory apparatus: sagittal sections on six slides.

Note

An unlabelled specimen from the original type material is not conspecific (see Discussion below and Supporting information, Table S1).

Distribution

Areas covered with Atlantic forest in the municipalities of Curitiba and Morretes, State of Paraná, South Brazil.

Diagnosis

Dorsal colour pattern constituted by a median mustard-coloured band, bounded on either side by a black band; entire dorsum sprinkled with conspicuous whitish specks. Penis bulb extending anteriorly 1.5 mm from penis papilla. Diameter of muscle muscular cylinder around ejaculatory duct equivalent to ten times the diameter of this duct. Female-to-male atrial length ratio, 2.

External aspect

Preserved adults 58 mm long and 4 mm wide. Body margins nearly parallel; anterior end rounded, posterior pointed. Dorsum strongly convex, ventral side flat. Dorsal body surface of live specimens constituted by a median mustard-coloured band (one-third of body width) that grades into the black of cephalic region (one-sixth of body length), bounded on either side by a black band (one-third); entire dorsum sprinkled with conspicuous whitish specks ( Fig. 24A, B ). Ventral surface whitish with blackish margins. The dorsal colours of preserved specimens collected in 2008 became slightly paler; the dorsal side of one specimen collected in 1952 consisted of a beige red median band bordered by greyish lateral bands. Two types of eyes: a conical type, in a single row around anterior tip; and a cupshaped type, spreading onto dorsum along lateral bands being one-third of body width. Relative position mouth-to-body length, 65%. Relative position gonopore-to-body length, 76%.

Internal morphology

Creeping sole 86% of body width. Glandular margin absent. Three typical geoplaninid cutaneous muscle layers present, being as thick as 6% of body height. Muscle fibres of the longitudinal, innermost layer (10– 20 µm thick) arranged into bundles with seven to 30 fibres each. Three parenchymal muscle layers present: dorsal layer of decussate diagonal fibres, supraintestinal layer of transverse fibres, and subintestinal layer with transverse fibres. Longitudinal fibres around intestine present, 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 30–45% of pharyngeal pocket length. Pharynx cylindrical; dorsal insertion posteriorly placed. Oesophagus-to-pharynx ratio, 14% ( Fig. 24C ). Outer pharyngeal musculature consisting of a thin subepithelial layer of longitudinal muscle, followed by a layer (35 µm) of intermingled circular and longitudinal muscle fibres. Inner pharynx musculature consisting of a thin subepithelial layer of longitudinal muscle, followed by a layer (38 µm) of circular fibres and an innermost layer (10 µm) of longitudinal fibres.

Testes dorsally located between supraintestinal parenchymal muscle layer and intestine; anteriormost testes very slightly anterior to ovarian region, posteriormost testes near root of pharynx. Penis bulb elongated, extending from 1.5 mm anterior to penis papilla to level of gonopore region; very strongly developed, consisting of tightly packed muscle fibres variously orientated proximally, whereas diagonally orientated distally. Distal fibres on the right side run obliquely downwards to embrace ventrally the anterior portion of the female atrium and subsequently anchor on ventral epidermis. Penis bulb more developed dorsally to male atrium than ventrally. Sperm ducts run dorsally, or slightly lateral to the ovovitelline ducts. Sperm ducts lined with a cuboidal, ciliated epithelium and surrounded by a 10- to 15-µm-thick layer of circular muscles. Ejaculatory duct lined with cuboidal, ciliated epithelium, pierced by gland cells apparently producing erythrophil granules; surrounded by a layer of circular muscles with maximal thickness of 140 µm on the posterior half, and constituting a muscular cylin- der with a diameter equivalent to ten times the diameter of this duct ( Fig. 24D–F ).

Penis papilla long, horizontal and cylindrical along most of its length, with dorsal and ventral insertions at the same transverse plane ( Fig. 24D, F ); posterior half of this papilla dilated, tapering to form a very narrow tip. Papilla occupies entire male and female atrium. Total length of papilla equal to seven times its greatest diameter. Papilla covered with a cuboidal, non-ciliated epithelium, pierced by gland cells producing erythrophil granules. A moderate space of 10 µm immediately beneath epithelium of mid-papilla fully packed by necks of gland cells producing cyanophil granules. Subepithelial musculature consisting of a dense layer of circular muscle, tending to decussate distally, 80 µm thick dorsally and 160 µm thick ventrally, followed by a 10-µm-thick layer of longitudinal muscle. Male atrium ample, not folded; lined with a low, non-ciliated epithelium, and underlain by a 10-µm-thick layer of circular muscles followed by a 10-µm-thick layer of longitudinal fibres.

Ovaries oval shaped, 500 µm in diameter in anteroposterior 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 the common glandular ovovitelline duct. Common glandular ovovitelline duct as long as approximately one-third of the female atrium length, and communicating with posterior portion of female atrium, the latter being 300 µm long, and bent posterodorsally.

Female atrium without folds, and being twice the length of the male atrium ( Fig. 24F ). Posterior section with 200 µm in length of female atrium lined with a 20-µm-high, stratified-like, non-ciliated epithelium, which is surrounded by a 30-µm-thick layer of very thin muscle fibres. Remaining epithelium of female atrium lined with cuboidal epithelium, pierced by gland cells producing erythrophil granules. This epithelium and that of female genital duct surrounded by 5- to 40-µm-thick layer of circular-to-decussate muscle fibres, followed by a 40- to 150-µm-thick layer of longitudinal fibres.

Figures

Figure 24. Geoplana chita Froehlich, 1956. A, dorsal view of the live specimen MZUSP PL 716, underdeveloped. B, drawings of dorsum of anterior end (left) and mid-region in dorsal view (top, right) and in three-dimensional section (bottom, right) of the body of a type specimen from Paraná; drawings by E. M. Froehlich; scale bar not available. C, photomicrograph of a sagittal section of the pharynx of specimen MZUSP PL 715. D, photomicrograph of a sagittal section of the copulatory apparatus of specimen MZUSP PL 2086. E, photomicrograph of part of the penis papilla of specimen MZUSP PL 2086 in sagittal section, showing the ejaculatory duct and its surrounding muscle. F, diagrammatic representation of the copulatory apparatus from sagittal sections of specimen MZUSP PL 2086.