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Grau, José Horacio, Almeida, Ana Laura, Sluys, Ronald, Carbayo, Fernando (2022): A new genus and two new species of land planarians (Platyhelminthes: Tricladida: Geoplanidae) from Southern Chile. Journal of Natural History 56 (13-16): 947-967, DOI: 10.1080/00222933.2022.2097137, URL: http://dx.doi.org/10.1080/00222933.2022.2097137

In this contribution, feeding behaviour assays with the three species Paucumara falcata, Dugesia sp. and Girardia sp. were used to investigate the function of the pharynx during feeding and whether absence of feeding behaviour until full regeneration is a widespread phenomenon among planarians from different taxonomic groups. Our results showed that feeding behaviour of decapitated flatworms was inhibited. Intact worms responded only to pork liver pieces, but isolated pharynges were highly responsive to both pork liver pieces and pork liver extracts. After transverse cutting, the oral part of the isolated pharynx was responsive, while the aboral part showed no response to food items, suggesting that the oral portion of pharynx plays a crucial role during feeding.

GIRARDIA CLANDESTINA SLUYS & BENÍTEZ- ÁLVAREZ SP. NOV. Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: zoobank. org:act: 6F75400B-1B3F-4B71-8351-5839C233019F Holotype: Naturalis Biodiversity Center, ZMA V.Pl. 976.4, Arroyo Sauce, near Sauce, Departamento Canelones, near Montevideo, Uruguay, 1–3 January 1987, sagittal sections on six slides. Etymology: The specific epithet is based on the Latin adjective clandestinus, secret, concealed, and alludes to the fact that it concerns a ‘hidden’ sibling species. Differential diagnosis: A species of Girardia with low triangular head with bluntly pointed tip and short, broad auricles. Dorsal body coloration variable, being of a reticulated type with darkish spots and also a pair of dark stripes, separated by a pale mid-dorsal streak or composed of a dark background interspersed with white splotches and with a pale mid-dorsal line, or variations on these two major patterns. Reproductive complex basically as in G. tigrina: the only consistent anatomical difference between the two species residing in the coat of muscles around the bursal canal. In North American G. tigrina, this coat of muscles is simple, consisting of a thin subepithelial layer of circular muscle, followed by an equally thin layer of longitudinal muscle fibres. In contrast, G. clandestina possesses a bursal canal musculature that consists of a well-developed coat of intermingled circular and longitudinal muscle fibres., Published as part of Benítez-Álvarez, Lisandra, Sluys, Ronald, Leal-Zanchet, Ana María, Leria, Laia & Riutort, Marta, 2023, First molecular phylogeny of the freshwater planarian genus Girardia (Platyhelminthes: Tricladida) unveils hidden taxonomic diversity and initiates resolution of its historical biogeography, pp. 1-19 in Zoological Journal of the Linnean Society 197 (1) on page 10, DOI: 10.1093/zoolinnean/zlac065, http://zenodo.org/record/7499040

Mapuplana guttulata sp. nov. Material examined Holotype. MNHNCL PLAT-15045 (Field code, F4906). Monumento Natural Contulmo, Purén, Región de La Araucanía, Chile, (38.000°S, 73.183°W), coll. F. Carbayo, 12 December 2010. Transverse sections of the cephalic and ovarian region on 31 slides; horizontal sections of a portion behind the cephalic region on 25 slides; transverse sections of the pre-pharyngeal region on 17 slides; sagittal sections of the pharynx and copulatory apparatus on 62 slides. Diagnosis Species of Mapuplana measuring about 50 mm in length; yellowish dorsum with a dark, minutely reticulated pattern. Ventral cutaneous musculature is thickest in parasagittal planes. Male atrium twice as long as the female atrium. Entire length of the female genital duct receives openings of shell glands. Gonoduct vertical. Female atrium ovoid. Type locality Monumento Natural Contulmo, Southern Chile. This small natural reservation (82 ha) is one of the few protected fragments of native forest in the region. The area is dominated by the Nothofagus temperate rainforest, receiving up to 1500 mm of rain per year. Etymology The specific epithet is derived from the Latin guttula, meaning droplet, and alludes to the dots and marks adorning the dorsum. Description External appearance. The live specimen measured approximately 50 mm in length and 5 mm in width, while preserved it was 30.5 mm long, 6 mm wide, and 2.8 mm thick. The body is lanceolate, with the dorsum convex and the ventral side being only slightly convex. From about halfway along its length, the body tapers towards the front end, giving rise to a narrow head with a rounded anterior margin. Posteriorly, the body first widens and then tapers, thus acquiring the shape of a broad arrowhead (Figure 2 (a)). In resting position, the dorsal surface is more or less corrugated, ie provided with wrinkles and folds. The ground colour of the dorsum is pastel yellow (RAL 1034), and it is adorned with scarce yellow-orange (RAL 2000) specks and numerous, small red-orange (RAL 2001) marks forming a minutely reticulated pattern (Figure 2 (a,b)). A broad mid-dorsal stripe (11% of body width) grades from yellow-orange at mid-body to red-orange at the extremities of the body. This median stripe is composed of two thinner lines in some regions of the body. The ventral surface bears the same colour pattern as the dorsal surface, albeit the median band is lighter (Figure 2 (c)). The eyes are monolobated, ranging between 45 and 82 µm in diameter. The eyecups are distributed in a single-to-double marginal row, contouring the very anterior body margin and extending on either side of the body to the posterior margin. Sensory pits are absent. Instead, spots of cilia, housed in slight depressions, are located at the ventro-lateral portion of the cephalic region (Figure 3 (a)). These sensory depressions are rare and inconspicuous, and were not observed in the anterior-most body region. The width of the creeping sole was difficult to measure in the pre-pharyngeal region because of the abundant erythrophil secretion adhering to the ventral surface, but it occupies 57% of the body width in the cephalic region. Relative position of the mouth: body length is 61% in relation to the anterior tip of the body; that of the gonopore:body length is 78%. Epidermis and its secretions. The epidermis is pierced by openings of three types of gland cells, producing erythrophil, cyanophil and xanthophil granules, respectively, with the erythrophil type being very abundant ventrally. In addition, rhabditogen cells pierce the dorsal and marginal portions of the epidermis. All types of glands are scarcer in the cephalic region. A glandular margin is absent (Figure 3 (b)). Cutaneous musculature. In the pre-pharyngeal region, the cutaneous musculature comprises three layers, namely a subepidermal circular layer (5–7.5 µm thick), followed by a double layer (12.5–20 µm) with decussate fibres, and a strong, innermost longitudinal muscle layer (Figure 3 (c)). The longitudinal musculature is 80 µm thick dorsally and 400 µm ventrally; dorsally, the fibres are gathered in large bundles (Figure 3 (c)). Ventrally the longitudinal musculature is divided into a subepidermal portion, which is about 65 µm thick and composed of small bundles, and a sunken dense portion, located beneath the cutaneous nerve plexus that measures 335 µm in thickness (Figure 3 (d,f)). In the pre-pharyngeal region of the body the cutaneous musculature thickness relative to the body height (abbreviated CMI) corresponds to 12.5% in the mid-sagittal plane. This value increases to 20% in parasagittal planes, due to an increase in the thickness of this musculature (Figure 3 (d,f)). Parenchymal musculature. There are four parenchymal muscle layers, viz. a dorsal layer of decussate fibres (30 µm thick, 1.0% of the body height), a supraintestinal layer (70– 80 µm) of transverse fibres, a subintestinal transverse muscle layer (65–83 µm), and a fourth, subneural layer with diagonal decussate fibres (90–120 µm); the subneural layer is embedded in the insunk ventral cutaneous muscle layer (Figure 3 (d)). Musculature in cephalic region. In the cephalic region, the musculature is relatively stronger than in the pre-pharyngeal region and it is also organised differently (Figure 4). At 1 mm from the anterior tip of the body, the ventral sunken longitudinal musculature is concentrated along the longitudinal body axis, so that it occupies about 67% of the body width, while the subepidermal portion represents 63% (Figure 4 (a)); in this region CMI is 35%. At 460 µm from the anterior tip of the body, the width of the subepidermal and sunken longitudinal muscle layers relative to body width and CMI decreases to 58% and 34%, respectively (Figure 4 (c,d)); in this region of the body the transverse muscle fibres are relatively more abundant than in the pre-pharyngeal region, while the subneural muscle fibres are restricted to mid-body. In this region, the sunken fibres are apparently oriented obliquely towards the dorsal body surface and to the body margins, but the precise path followed by these fibres was not discernible beyond the central nervous system (Figure 4 (c)). At 100 µm from the anterior tip, the sunken portion of the ventral longitudinal cutaneous musculature is lacking, while the subepidermal portion is still present. Pharynx. The cylindrical pharynx is located at a short distance behind the middle of the body and projects out of the mouth opening, the latter situated at the posterior end of the pharyngeal pouch (Figure 5 (a)). The oesophagus is 0.5 mm long. The pharyngeal pouch musculature is composed of subepithelial longitudinal muscle fibres, followed by circular fibres. The outer pharyngeal musculature consists of a subepithelial longitudinal muscle layer (8 µm thick), followed by a layer of circular muscles (20–25 µm thick). Underneath this coat of muscles, there is a 200 µm thick layer of intermingled longitudinal and circular muscle fibres. The inner pharyngeal musculature consists of a single, subepithelial layer of intermingled circular and longitudinal fibres (120–225 µm thick) (Figure 5 (b)). Radial muscle fibres are also present. Two types of glands, producing granular erythrophil and xanthophil secretions, respectively, run through the parenchyma of the pharynx and discharge their contents at the tip of the pharynx. Male reproductive system. The globular testes, measuring 210–320 µm in diameter, are distributed in two rows on either side of the body between the supra-intestinal transversal parenchymatic muscle layer and the intestinal diverticula (Figure 3 (b,c)). The anterior-most testes are located at a distance from the anterior tip of the body equivalent to 22% of the body length; the posterior-most testes are located at the equivalent of 50% of body length, as measured from the anterior margin, ie they are distributed anteriorly to the root of the pharynx. The sperm ducts run immediately above the sub-intestinal parenchymal musculature and slightly laterally to the oviducts. Posterior to the pharynx, these ducts are sinuous and dilated, thus forming spermiducal vesicles, which are packed with spermatozoa. The posterior portions of the spermiducal vesicles narrow considerably while curving postero-dorsad and, subsequently, communicate with a branch of one of the highly ramified glands of the tubular prostatic vesicle. This communication of the sperm ducts with the ducts of the prostatic glands takes place via a transitional canal lined with a low epithelium, which is surrounded by a 10 µm thick layer of circular muscle. These two glands consist of numerous ramified ducts, which measure 15–37 µm in diameter and are lined with a 37–40 µm high, ciliated epithelium. These ducts collect erythrophil and xanthophil granular secretions, produced by gland cells located all around the tubules (Figures 5 (c) and 6(c,d)). The tubular glands join before opening into the very proximal, posterior portion of the prostatic vesicle (Figure 5 (c)). The unpaired tubular prostatic vesicle follows a spiralling trajectory (Figures 5 (c) and 6 (b,c)) before it penetrates the ventral musculature of the common muscle coat and, subsequently, ascends to open into the ejaculatory duct. The proximal, anterior portion of the prostatic vesicle measures 35–50 µm in diameter, while its distal section measures 10–18 µm (Figures 5 (c) and 6(b,c)). The prostatic vesicle is lined with a cuboidal, ciliated epithelium and is surrounded by a 50–75 µm thick layer of circular muscle. On its way through the penis papilla, this duct doubles its diameter to 60 µm before narrowing again to open at the tip of the papilla through an opening with a diameter of about 5 µm. The ejaculatory duct is lined with a ciliated epithelium and is surrounded by a 30 µm thick layer of circular musculature. The small penis papilla is conical, with its length corresponding to about 9% of the length of the male atrium (Figures 5 (c) and 6(e)). This papilla projects from the anterodorsal portion of the male atrium and points postero-ventrally; it is covered with an infranucleated epithelium, which is pierced by two types of gland cells, producing xanthophil and cyanophil granules, respectively. The epithelium of the penis papilla is underlain by a 17–20 µm thick, subepithelial layer of circular muscle, followed by a 15– 33 µm thick layer of longitudinal fibres. The male atrium is long, provided with distinct folds and lined with a low epithelium. (Figures 5 (c) and 6(a,b)).Two large,transverse flap-shaped folds occupy the anterior half of the male atrium. One flap is ventral to the penis papilla, the other posterior to it. The posterior half of the male atrium is occupied by two oblique folds, the anterior one being narrower than the posterior one. The basement membrane underlying the epithelium that is located between the flaps, as well as that between the oblique folds, is 4–8 times thicker than in any other region of the atrium. The entire epithelium of the male atrium is pierced by openings of gland cells producing erythrophil granules, while it is underlain by a 18–35 µm thick layer of circular muscle fibres. Transverse and longitudinal muscle fibres are abundant in the flaps and oblique folds. Additionally, the posterior oblique and narrow fold is reinforced with a 75–85 µm thick coat of intermingled circular and longitudinal muscle fibres. A strongly xanthophil clump, 250 × 350 µm in size, is attached to the wall of the atrium between the two oblique folds; the atrial surface where the clump is attached lacks epithelium (Figures 6 (b) and 7(a)). Female reproductive system. A single pair of ovaries is located at a distance from the anterior tip of the body corresponding to 23% of the body length, with the gonads being situated on top of the ventral nerve plate and underneath the transverse sub-intestinal parenchymal muscle layer. The ovaries are approximately globular, measuring about 250 µm in diameter. The ovovitelline ducts emerge from the dorsal wall of the ovaries and, thereafter, run above the nerve plate. Posteriorly to the gonopore, the ducts ascend to open into the female genital duct, which is about 120 µm wide and curves antero-dorsally to communicate with the female atrium (ie proflex with anterior approach; Figure 5 (c)). Approximately two-thirds of the length of the female genital duct receives the openings of shell glands; at the point of communication with the female atrium, this duct diminishes somewhat in diameter (Figures 5 (c) and 7(b,c)). The female genital duct is lined with a columnar epithelium, with the apical portion of its cells containing xanthophil granules. The gonoduct originates from the mid-ventral wall of the female atrium, the latter being spacious and more or less ovoid in shape, with its length being about half of that of the male atrium (Figures 5 (c) and 7(b,c)). The female atrium is lined with a 40–100 µm high, somewhat irregular, nucleated epithelium, which exhibits some recesses that are sunken into the underlying parenchyma (Figure 7 (d)). The cytoplasmic membrane of the epithelial cells could not be recognised. Most of the cytoplasm of these cells has low affinity for stain, while the apical portion of the cells is provided with a bright, xanthophil secretion. The female atrium is surrounded by a 25 µm thick, subepithelial, layer of circular musculature, followed by a loose coat of longitudinal fibres. A blind duct, measuring about 140 µm in width and 520 µm in length, opens into the antero-lateral region of the female atrium (Figures 5 (c) and 7(e,f)). This duct is lined with a cuboidal epithelium, which is pierced by the openings of two types of gland cells, producing erythrophil and cyanophil granules, respectively. The blind duct is surrounded by a 20 µm thick layer of circular muscle. The female atrium houses a spermatophore, with a shape between ovate and quadrate (Figures 6 (a) and 7(c)), about 550 × 300 µm in size. It is composed of a strongly xanthophil substance – similar to that of the clump in the male atrium – and is amorphous in its central portion, whereas it is fibrous at its periphery. Small portions at the innermost region of the spermatophore contain sperm. The common muscular coat consists of longitudinal and oblique muscle fibres, and surrounds the distal region of the prostatic vesicle, the male and female atria, and the female genital duct., Published as part of Grau, José Horacio, Almeida, Ana Laura, Sluys, Ronald & Carbayo, Fernando, 2022, A new genus and two new species of land planarians (Platyhelminthes: Tricladida: Geoplanidae) from Southern Chile, pp. 947-967 in Journal of Natural History 56 (13 - 16) on pages 950-958, DOI: 10.1080/00222933.2022.2097137, http://zenodo.org/record/7012240

Mapuplana fjordica sp. nov. Material examined Holotype ZMB 11512. Puerto Gaviota, Magdalena Island, Chonos Archipelago, Southern Chile (44°40′0″S, 73°8′0″W), coll. J.H. Grau, 27 January 2007. Transverse sections of the cephalic and ovarian region on 14 slides; horizontal sections of a portion behind the cephalic region on seven slides; transverse sections of the pre-pharyngeal region on four slides; sagittal sections of the pharynx and copulatory apparatus on 34 slides. Type locality Puerto Gaviota, Magdalena Island, Chonos Archipelago, Southern Chile. The worm was collected from beneath fallen wood near Puerto Gaviota in Magdalena Island, Southern Chile (44°40′0″S, 73°8′0″W). This region is characterised by the Valdivian temperate rainforest and receives up to 4000 mm of rain per year. Etymology The specific epithet refers to the word fjord, alluding to the landscape of the Chonos Archipelago. Diagnosis Species of Mapuplana about 40 mm in length with yellowish dorsum with numerous short, longitudinal dark striae. Ventral cutaneous musculature thickest in the median region of the body. Male atrium 2.4 times longer than female atrium. Proximal portion of the female genital duct lacks openings of shell glands. Gonoduct obliquely oriented, with postero-dorsal inclination. Female atrium with irregular shape. Description External appearance. The live specimen measured about 40 mm in length and 3 mm in width; preserved it measured 25 × 6 mm, with a thickness of 1.4 mm. The body is lanceolate, dorsally convex and ventrally flat. The anterior tip is rounded and the posterior one obtusely pointed (Figure 8). At rest, the dorsum is corrugated (Figure 8 (a)). The ground colour of the dorsal body surface is yellow-orange (RAL 2000), while it is provided with a pair of thin, mid-dorsal, orange-brown (RAL 8023) longitudinal stripes. Furthermore, numerous short and anastomosing longitudinal stripes, with the same orange-brown colour, are spread all over the dorsum, except the paramedian region (Figure 8 (a)). The ventral side of the preserved specimen exhibited the same pattern of pigmentation as the dorsum, albeit paler, while the anterior extremity was greyish (Figure 8 (d)). The eyes are monolobated, and measure approximately 40 µm in diameter. The eyecups contour the anterior tip of the body and extend in a single row along the entire lateral body margin. Sensory pits are absent. The creeping sole is about 80% of the body width (Figure 9 (a)). The relative position of the mouth:body length is 77% in relation to the anterior tip of the body, while that of the gonopore:body length is 83%. Epidermis and its secretions. The dorsal and ventral epithelia are about 27 µm in height and are pierced by the openings of gland cells, producing an erythrophil, granular secretion. Rhabditogen cells open onto the latero-dorsal surface, as well as the lateral body margins. A glandular margin is absent. Cutaneous musculature. The cutaneous musculature consists of a subepidermal layer of circular muscle, followed by a double diagonal muscle layer and a layer of longitudinal fibres. The longitudinal muscle layer consists of large bundles and is about 85 µm thick dorsally, while it measures 240 µm ventrally (Figures 9 and 10 (a,b)). A 30 µm thick portion of the ventral longitudinal muscle is subepidermal and consists of fibres that are gathered into bundles of 10–15 fibres, while a 210 µm thick portion of the ventral longitudinal muscle is composed of fibres joined into bundles of 8–25 fibres, and is sunken into the parenchyma. The cutaneous musculature thickness relative to the body height in the prepharyngeal region corresponds to 27%. Parenchymal musculature. There are four parenchymal muscle layers, namely a dorsal layer of decussate fibres (28 µm thick, 2.0% of the body height), a supraintestinal transverse muscle layer (40 µm), a subintestinal transverse muscle layer (30 µm), and a layer of subneural muscle with diagonal decussate fibres (170 µm); the decussate fibres and those of the insunk ventral cutaneous muscle layer are intermingled (Figures 9 (d) and 10(a,b)). Musculature in cephalic region. Towards the anterior tip of the body the muscle layers gradually strengthen, so that the CMI here reaches a value of 28% (Figure 10 (c,d)). Unfortunately, similar stain affinities of muscle fibres and gland cells hinder clear visualisation of the arrangement of the fibres. Pharynx. The mouth is located at a distance from the anterior region of the pharyngeal pouch equivalent to 64% of its length (Figure 11 (a)). The oesophagus is about 15% of the length of the pharynx, which is cylindrical and occupies most of the pharyngeal pouch. The epithelium of the pharyngeal pouch is underlain by a layer of circular muscle. The outer pharyngeal epithelium is underlain by a layer of subepidermal longitudinal muscle (6 µm thick), followed by a layer of circular muscle (12 µm thick). Immediately underneath this circular muscle layer is located a 100–110 µm thick layer of intermingled longitudinal and circular muscle fibres that projects from the pharynx anteriorly into the adjacent parenchyma. The inner pharyngeal epithelium is underlain by a layer of intermingled circular and longitudinal muscle fibres (130–145 µm thick) (Figure 11 (a,b)). Radial muscle fibres are also present. Erythrophil and cyanophil granular secretions run through the parenchyma of the pharynx and are discharged at its tip. Male reproductive apparatus. The testes are ovoid, measuring 150–170 µm in diameter; the follicles are located dorsally between the intestinal branches and the supra-intestinal transversal parenchymal muscle layer. They are arranged in multiple irregular rows on either side of the body. The testes are prepharyngeal, with the anterior-most ones being located at a distance of 2934 µm from the anterior tip of the body and the posterior-most follicles positioned just anterior to the root of the pharynx. The sperm ducts run immediately above the sub-intestinal parenchymal muscle layer and slightly laterally to the oviducts. Behind the pharyngeal region, the sperm ducts gradually expand to form spermiducal vesicles, which are packed with spermatozoa. Shortly behind the pharynx these ducts curve dorsally and open separately into one of the tubules of the prostatic vesicle glands (Figure 11 (c)). The latter communicate with the tubular prostatic vesicle by means of several connections, which are very difficult to discern and reconstruct. In point of fact, one of the sperm ducts communicates at a rather ventral position with a tubule of the prostatic vesicle gland and for this gland we were unable to find its connection with the prostatic vesicle. The latter consists of a winding, extra-bulbar duct with a diameter of about 25 µm, while it is considerably narrower at its anterior and posterior extremities. The prostatic vesicle penetrates the antero-ventral region of the penis bulb and, thereafter, ascends vertically in a coiled fashion to communicate with the ejaculatory duct (Figure 11 (e)). This prostatic vesicle is lined with a cuboidal, nucleated and ciliated epithelium and is surrounded by a coat of circular muscle between 40 and 100 µm in diameter. This layer of circular muscle is followed by a muscle web that surrounds the entire prostatic vesicle and attaches to the penis bulb. In some histological sections, this muscle web seems to be a continuation of the common muscle coat. There are two prostatic vesicle glands, one on either side of the body, consisting of highly branched tubules, lined with a cuboidal, nucleated and ciliated epithelium (Figure 11 (c,e)). The numerous branching tubules, which are surrounded by a thin layer of circular muscle, collect the erythrophil, granular secretion produced by the surrounding gland cells. The ejaculatory duct horizontally traverses the penis papilla to exit at its tip through a narrow opening (Figure 11 (e)); the duct is lined with a ciliated, cuboidal epithelium and is surrounded by a 25 µm thick layer of circular musculature. The small, conical penis papilla is horizontally oriented, projects from the antero-dorsal wall of the male atrium and measures about 10% of the length of the atrium. The musculature of the penis papilla consists of a subepithelial layer of circular muscle, followed by a layer of longitudinal fibres. The male atrium is ample and provided with 2–3 large transverse folds, and is about 2.4 times as long as the female atrium. The epithelium of the male atrium is cuboidal and is pierced by openings of scarce glands, producing an amorphous, cyanophil secretion. This epithelium is underlain by a 20–30 µm thick layer of circular muscle, which is continuous with a net of abundant muscle fibres without any definite orientation. Female reproductive system. A single pair of ovaries is located at the posterior end of the anterior third of the body, with the gonads being placed immediately above the ventral nerve plate and directly underneath the transversal sub-intestinal parenchymal muscle layer. The globular ovaries measure about 200 µm in diameter. The ovovitelline ducts arise from the dorsal surface of the ovaries and run posteriorly immediately above the ventral nerve plate. Posteriorly to the gonopore, the oviducts ascend to open into the female genital duct (Figure 11 (e)). The latter receives the openings of shell glands along approximately 60% of its anterior length, while it curves antero-dorsad to open into the female atrium. The gonoduct originates at the postero-ventral wall of the female atrium, the latter being rather small and having an irregular shape, while it is surrounded by a layer of circular muscle fibres. The female atrium is lined with columnar cells with basal nuclei in which an erythophil, granular secretion accumulates in the apical portions of the cells. A blind duct originates from the lateral wall of the female atrium on the left side of the animal, but quickly assumes a vertical orientation when it projects into the adjacent parenchyma, while being embedded in the musculature of the female atrium (Figure 11 (e,f)). This duct measures about 200–300 µm in length and about 50–100 µm in diameter. Basically, the histology of this blind duct is the same as that of the female atrium, including the erythrophil secretion accumulating in the apical portions of the cells. However, in contrast to the female atrium, the epithelium of the blind duct is pierced by abundant openings of gland cells lying around the duct, producing an amorphous cyanophil secretion. The common muscular coat surrounds the distal ascending portion of the prostatic vesicle, the male atrium, female atrium, and female genital duct and consists of longitudinal and obliquely running muscle fibres.

Genus Mapuplana gen. nov. Diagnosis Geoplaninae with a flattened, slightly lanceolate body, ranging between 40 and 50 mm in length. Monolobulated eyes surround the entire cephalic region. Sensory depressions present. Thickness of cutaneous muscle relative to body height: 12.5–27%. Ventral longitudinal cutaneous musculature partially sunken beneath the peripheral nervous plexus and below the main nerve plate. Musculature in the cephalic region thicker. Subneural parenchymal musculature consisting of diagonal decussate fibres, intermingled with the sunken portion of the ventral longitudinal cutaneous musculature. Prostatic vesicle receives the secretion of tubular, branched glands. Eversible penis type; penis papilla small and conical. A blind duct opens into the left side of the female atrium. Female genital duct projects postero-ventrally from the postero-dorsal region of the female atrium. Type species Mapuplana guttulata sp. nov. Distribution Purén (Región de La Araucanía) and Chonos Archipelago (Región de Aisén), Chile. Etymology The generic epithet refers to the native Mapuche nation of Southern South America, plus plana, meaning flat.